Hi there. I don't believe I'll be posting any more, seeing how this whole fiasco is wrapping up, at least the visible portions. I have been, and will continue to follow, the studies concerning microbial breakdowns of the various hydrocarbon fractions in the G.o.M., for I feel the effects will be seen more noticeably after we experience another cycle of the seasons. Take in mind when you read the articles on this blog, that there are many inaccuracies, and misunderstandings of data I read and accumulated, especially geo-data & chemistry.
In 5 months.I learned a great deal, in fact, enough to convince myself to go back to school in the spring,... a daunting task for a 38 year old high-school dropout, but one I am looking forward to, all the same.. I'm sure you have, and hopefully will to continue to seek education and clarity surrounding this event. Any questions or insults can be sent to me via email isaacnd200@gmail.com
As a parting thought, because we should really all be reminding each other to seek rational explanations for the things we see.~ Data and logic sometimes appear to be at odds with each other, but by examining causalities in public forum, we will always find the rational.
" Remember not to let yourself become jaded when all the misapplications of the science are weighed in. It is the application of the science when inappropriate or the lack of application of the science when it is appropriate that causes distress in the reasonable man."
Wednesday, September 22, 2010
Wednesday, September 8, 2010
Sodium bis(2-ethylhexyl)sulfosuccinate, the anionic surfactant in COREXIT 9500
*DISCLAIMER* I AM NOT A CHEMIST, I AM ONLY COMPILING INFORMATION FOR THE READER.
---------------------------------------------------------------
Sodium bis(2-ethylhexyl) sulfosuccinate (C20H37NaO7S), often referred to as docusate sodium, Aerosol OT or AOT, is an anionic surfactant and a common ingredient in consumer products, especially laxatives of the stool softener type. AOT is the most widely used surfactant in reverse micelle encapsulation studies It is also a component of the oil dispersant Corexit.
【RTECS Class】
【Appearance】
Odorless colorless to white waxy solid.
【Odor threshold】
Odorless
【Decomposition】
Carbon monoxide, oxides of sulfur, carbon dioxide.
OXIDES OF SULFUR :
Sulfur dioxide (SO2) and sulfur trioxide (SO3)
http://www.windows2universe.org/physical_science/chemistry/sulfur_oxides.html
http://en.wikipedia.org/wiki/Dioctyl_sodium_sulfonsuccinate
---------------------------------------------------------------
Sodium bis(2-ethylhexyl) sulfosuccinate (C20H37NaO7S), often referred to as docusate sodium, Aerosol OT or AOT, is an anionic surfactant and a common ingredient in consumer products, especially laxatives of the stool softener type. AOT is the most widely used surfactant in reverse micelle encapsulation studies It is also a component of the oil dispersant Corexit.
Bis(2-ethylhexyl) sulfosuccinate sodium salt(577-11-7)
【RTECS Class】
Reproductive Effector; Primary Irritant
【Appearance】Odorless colorless to white waxy solid.
【Odor threshold】
Odorless
【Decomposition】
Carbon monoxide, oxides of sulfur, carbon dioxide.
OXIDES OF SULFUR :
Sulfur dioxide (SO2) and sulfur trioxide (SO3)
http://www.windows2universe.org/physical_science/chemistry/sulfur_oxides.html
General
- Synonyms: bis(2-ethylhexyl)sulfosuccinate sodium salt, bis(2-ethylhexyl)sodium sulfosuccinate, dioctyl sulfosuccinate sodium salt, dioctyl sodium succinate, a very wide range of further synonyms and trade names, including aerosol OT, cloace, doxol, doxinate, colace, molatoc, norval, obston, rapisol, docusate sodium, duosol, dulsivac, konlax, kosate
Use: wetting, solubilising and dispersal agent
Molecular formula: C20H37NaO7S
CAS No: 577-11-7
EINECS No: 209-406-4
Physical data
- Appearance: white solid, often supplied as an aqueous solution
Melting point: 173 - 179 C
Boiling point:
Vapour density:
Vapour pressure:
Density (g cm-3):
Flash point:
Explosion limits:
Autoignition temperature:
Water solubility: appreciable
Stability
- Stable. Combustible. Incompatible with strong oxidizing agents.
Toxicology
- Harmful if swallowed. May be harmful if inhaled or absorbed through skin. Skin and respiratory irritant. Severe eye irritant. Toxicity data
(The meaning of any toxicological abbreviations which appear in this section is given here.)
ORL-RAT LD50 1900 mg kg-1
IPR-RAT LD50 590 mg kg-1
ORL-MUS LD50 2643 mg kg-1
IVN-MUS LD50 60 mg kg-1
Risk phrases
(The meaning of any risk phrases which appear in this section is given here.)
R22 R38 R41.
Transport information
- Non-hazardous for air, sea and road freight.
Personal protection
- Safety glasses. Safety phrases
(The meaning of any safety phrases which appear in this section is given here.)
S26 S36.
http://msds.chem.ox.ac.uk/DI/dioctyl_sulfosuccinate_sodium.html
http://en.wikipedia.org/wiki/Dioctyl_sodium_sulfonsuccinate
Monday, September 6, 2010
Emulsified at the wellhead , revisited
So I continued to read up on emulsions, out of curiosity over what possibly was happening at the wellhead, originally, because there have been no previous studies confirming/disproving the effectiveness of surfactants applied to crude oil at high pressures and high temperatures. After checking into things a little more, I am doubtful of ultrasound or ultrasonic transducers being used to emulsify the oil, the equipment is not powerful enough to have any effect, but I could very well be wrong about it.
(In retrospect, I do still consider possible effects from entrained methane/H2S on the dispersed oil if there was any notable effect on the acidity of the local water during the time the oil was still flowing.)
I thought this was very odd, given the decision to apply COREXIT at the wellhead, given there is no precedence in the situation.
Here's my theory/thoughts:
I think that any chemist or engineer in the petrochemical industry ( which I am definitely not ) is well aware of cavitation and emulsions. " Hydrodynamic Cavitation Emulsion " is the term. When you emusify hydrocarbons for any reason, you add surfactants to aid in the emulsion. I honestly think that somebody realized that there was a massive opportunity to possibly to aid in emulsifying the oil at the wellhead since it was already being cavitated by the turbidity induced in the flowpath from the obstructions of the stuck drillpipe sections.
The concept is simple really, a denser fluid passes at high pressure & high temperature through an obstructed( read constricted/reduced ) flowpath, which causes the cavitation as it passes through the area back into an area of lower pressure, where it cavitates in the other fluid ( seawater ) and surfactants are added to stabilize the emulsion. The effect is greatly sped up due to the temperature difference and the ability of the ocean to act like a heatsink. The oil coming out of the wellhead is IIRC around 212-F, which drops almost immediately to the ambient temperature-37-F If you have ever seen what happens to emulsified salad dressing when you refrigerated it, you understand what I am talking about. The temperature is one of the things that actually helps keep the emulsion from breaking. You could make the same salad dressing and leave it out on the counter, it will eventually break, especially since you have not used surfactants in it......Sodium bis(2-ethylhexyl)sulfosuccinate is also a laxative, so you'd have to have one twisted sense of humor to do that to somebody,...anyway.....( that's the primary surfactant in COREXIT ). This post is put together with some fairly technical babble, just a warning. I have cited some diverse sources, so hold on to your hat.
There are typically 3 sizes of emulsions considered , with microemulsions and nanoemulsions being the smaller of the 3, they actually tend to appear clear due to the small size of the disperse phase, which also makes them very hard to see.
There are three types of emulsion instability: flocculation, creaming, and coalescence. Flocculation describes the process by which the dispersed phase comes out of suspension in flakes. Coalescence is another form of instability, which describes when small droplets combine to form progressively larger ones. Emulsions can also undergo creaming, the migration of one of the substances to the top (or the bottom, depending on the relative densities of the two phases) of the emulsion under the influence of buoyancy or centripetal force when a centrifuge is used.
Here is a great, easy to read PDF , with visuals to show what emulsion stability is and how what happens,... happens.
http://wefcol.vub.ac.be/wefcol/lectures/Hanoi/h6.pdf
Surface active substances (surfactants) can increase the kinetic stability of emulsions greatly so that, once formed, the emulsion does not change significantly over years of storage.
The Bancroft Rule applies:
The Bancroft rule states: "The phase in which an emulsifier is more soluble constitutes the continuous phase."
It was named after Wilder Dwight Bancroft, an American physical chemist.
In all of the typical emulsions, there are tiny particles (discrete phase) suspended in a liquid (continuous phase). In an oil-in-water emulsion, oil is the discrete phase, while water is the continuous phase.
What the Bancroft rule states is that contrary to common sense, what makes an emulsion oil-in-water or water-in-oil is not the relative percentages of oil or water, but which phase the emulsifier is more soluble in. So even though there may be a formula that's 60% oil and 40% water, if the emulsifier chosen is more soluble in water, it will create an oil-in-water system.
There are some exceptions to Bancroft's rule, but it's a very useful rule of thumb for most systems.
The Hydrophilic-lipophilic balance (or HLB) of a surfactant can be used in order to determine whether it's a good choice for the desired emulsion or not.
Surfactants have 4 classifications :anionic, cationic, non-ionic, and zwitterionic.( BTW, I was wrong about it being a Zwitt. bond.)
Sodium bis(2-ethylhexyl)sulfosuccinate ( Primary in C9500a) is anionic, from what I have learned, it's a hydrogen bond.
The length of hydrogen bonds depends on bond strength, temperature, and pressure. The bond strength itself is dependent on temperature, pressure, bond angle, and environment.They can vary in strength from very weak to extremely strong.
..Then, if you read the post I put up the other day, you see there are 3 phases of oil released underwater.
Jet Phase: The speed of the oil and natural gas being expelled from the pressurized, confined space of the well into the water makes the oil form droplets and the gas form bubbles.
Plume Phase: The momentum of these tiny droplets and bubbles drags significant volumes of sea water upward into the water column, forming a plume. In deeper water, so much water is incorporated into the plume that eventually, the oil–natural gas–water mix is no longer buoyant, and the plume will become suspended at what is called the terminal layer. If heavier components sink out of the suspension, the plume may reform and begin to rise again.
Post-terminal Phase: Once the plume reaches the final terminal layer, the rise of the oil and gas to the surface is driven purely by the buoyancy of the individual droplets and bubbles.
So that gives us: 3 sizes of emulsions, 3 types of emulsion stabilities, and 3 phases for aqueous oil dispersion.
An emulsion created by cavitation is perhaps the most effective, in terms of small particles size..
From the Arisdyne website , I would recommend watching the video:
Hydrodynamic Cavitation can occur in any turbulent fluid. The turbulence produces an area of greatly reduced fluid pressure. The fluid vaporizes due to the low pressure, forming a cavity. At the edges of the cavity, small amounts of vapor break off. These form smaller cavities 100 nm to 3 mm in diameter. The smaller cavities implode under the high pressure surrounding them. This process of formation and collapse is called cavitation.
Cavitation is an enormously powerful process. Conditions in the collapsing cavity can reach 5000°C and 1000 atmospheres. The implosion takes place during the cavitation process in milliseconds, releasing tremendous energy in the form of shockwaves. The power of these waves generated by the cavitation process disrupts anything in their path.
...so that's my little bit on cavitation. On to fluid flows at high velocities.
" In some prior art Blowout Preventer (BOP) operating systems, high velocity fluid flows and low differential pressures induced vibration in the system. This vibration may result in collapse and failure of hydraulic hoses in the system. A quick dump valve has been added at or near the open port on the BOP assembly to reduce vibration and other problems. The dump valve has a vent position and an open position. Several alternative embodiments add a ball check valve assembly to the shuttle in the quick dump valve."
http://www.patents.com/F-Harold-Hollister/Richmond/TX/3128164/inventors/
I included that one so's you know it's an actual problem, and not a figment of my imagination.Thank you Mr Hollister.
In a two-dimensional supersonic flow around a blunt body (see illustration), a normal shock is formed directly in front of the body, and extends around the body as a curved oblique shock. At a sufficient distance away, the flow field is unaffected by the presence of the body, and no discontinuity in velocity occurs. The shock then reduces to a Mach wave.
Supersonic fluid separation enhanced by spray injection
The separation of liquid and/or solid components from a multiphase fluid stream passing through a supersonic fluid separator is enhanced by injecting a surface active agent ( READ: SURFACTANT )into the fluid stream passing through the separator. Preferably the spray is injected via an injection tube that has a positive or negative electrical potential, whereas one of the walls of the separator housing has an opposite electrical potential, so that the injected spray and any liquid droplets and/or particles formed around the injected nuclei are induced to flow towards said electrically loaded wall.
http://www.freepatentsonline.com/7261766.html
Shocks waves form because information about conditions downstream of a point of sonic or supersonic flow can not propagate back upstream past the sonic point.
The behavior of a fluid changes radically as it starts to move above the speed of sound (in that fluid). For example, in subsonic flow, a stream tube in an accelerating flow contracts. But in a supersonic flow, a stream tube in an accelerating flow expands. To interpret this in another way, consider steady flow in a tube that has a sudden expansion: the tube's cross section suddenly widens, so the cross-sectional area increases.
In subsonic flow, the fluid speed drops after the expansion (as expected). In supersonic flow, the fluid speed increases. This sounds like a contradiction, but it isn't: the mass flux is conserved but because supersonic flow allows the density to change, the volume flux is not constant.
So the fluid passing through the wellhead would have been restricted by the partially closed blind ram, and the trapped drillpipe sections. You could call that "choking back the flow ". The following from OnePetro:
" Wellhead chokes are installed on wells to control flow rates and to protect the reservoir and surface equipment from pressure fluctuations. Flow through the choke can be described as either critical or subcritical. In the critical-flow region, the mass flow rate reaches a maximum value that is independent of the pressure drop applied across the choke. Therefore, once critical flow is reached, any dis-turbance introduced downstream of the choke will have no effect on upstream conditions. Therefore, chokes are commonly operated under critical-flow conditions to isolate the reservoir from pressure fluctuations introduced by surface processing equipment.
A second use of wellhead chokes is to monitor production rates by operating in the subcritical-flow region, especially when oil and gas are produced from offshore or hostile environments. For these applications, it is advantageous to use MOV chokes that allow the size of the choke opening to be changed while the choke is under pressure without interruption of production. With this feature, the pressure drop across the choke, and thereby manipulation of the flow rate, can be remotely controlled. Surbey et al. I discussed in detail the application of MOV chokes in the subcritical-flow region.
This investigation presents the application of MOV chokes in the critical-flow region. The limitations of conventional correlations in predicting critical-flow behavior for MOV chokes is also discussed. A new correlation is presented to predict the transition between critical and subcritical flow that is applicable to conventional chokes as well."
To end this post :
I hope since they have finally managed to bring the BOP to the surface, that there will be some closure in this matter. We could say without a doubt, that there were certainly some effects on the phases of the oil in the water that may have had something to do with what was happening at the wellhead, ie: the COREXIT products being applied, and the restrictions in the flow.
http://www.freepatentsonline.com/4011661.html
http://www.economicexpert.com/a/Compressible:flow.htm
http://encyclopedia2.thefreedictionary.com/Supersonic+flowhttp://conhira.com/english/goods/safety.html
http://cavitronix.com/how-it-works/
http://en.wikipedia.org/wiki/Emulsify
http://en.wikipedia.org/wiki/Bancroft_rule
(In retrospect, I do still consider possible effects from entrained methane/H2S on the dispersed oil if there was any notable effect on the acidity of the local water during the time the oil was still flowing.)
I thought this was very odd, given the decision to apply COREXIT at the wellhead, given there is no precedence in the situation.
Here's my theory/thoughts:
I think that any chemist or engineer in the petrochemical industry ( which I am definitely not ) is well aware of cavitation and emulsions. " Hydrodynamic Cavitation Emulsion " is the term. When you emusify hydrocarbons for any reason, you add surfactants to aid in the emulsion. I honestly think that somebody realized that there was a massive opportunity to possibly to aid in emulsifying the oil at the wellhead since it was already being cavitated by the turbidity induced in the flowpath from the obstructions of the stuck drillpipe sections.
The concept is simple really, a denser fluid passes at high pressure & high temperature through an obstructed( read constricted/reduced ) flowpath, which causes the cavitation as it passes through the area back into an area of lower pressure, where it cavitates in the other fluid ( seawater ) and surfactants are added to stabilize the emulsion. The effect is greatly sped up due to the temperature difference and the ability of the ocean to act like a heatsink. The oil coming out of the wellhead is IIRC around 212-F, which drops almost immediately to the ambient temperature-37-F If you have ever seen what happens to emulsified salad dressing when you refrigerated it, you understand what I am talking about. The temperature is one of the things that actually helps keep the emulsion from breaking. You could make the same salad dressing and leave it out on the counter, it will eventually break, especially since you have not used surfactants in it......Sodium bis(2-ethylhexyl)sulfosuccinate is also a laxative, so you'd have to have one twisted sense of humor to do that to somebody,...anyway.....( that's the primary surfactant in COREXIT ). This post is put together with some fairly technical babble, just a warning. I have cited some diverse sources, so hold on to your hat.
There are typically 3 sizes of emulsions considered , with microemulsions and nanoemulsions being the smaller of the 3, they actually tend to appear clear due to the small size of the disperse phase, which also makes them very hard to see.
There are three types of emulsion instability: flocculation, creaming, and coalescence. Flocculation describes the process by which the dispersed phase comes out of suspension in flakes. Coalescence is another form of instability, which describes when small droplets combine to form progressively larger ones. Emulsions can also undergo creaming, the migration of one of the substances to the top (or the bottom, depending on the relative densities of the two phases) of the emulsion under the influence of buoyancy or centripetal force when a centrifuge is used.
Here is a great, easy to read PDF , with visuals to show what emulsion stability is and how what happens,... happens.
http://wefcol.vub.ac.be/wefcol/lectures/Hanoi/h6.pdf
Surface active substances (surfactants) can increase the kinetic stability of emulsions greatly so that, once formed, the emulsion does not change significantly over years of storage.
The Bancroft Rule applies:
The Bancroft rule states: "The phase in which an emulsifier is more soluble constitutes the continuous phase."
It was named after Wilder Dwight Bancroft, an American physical chemist.
In all of the typical emulsions, there are tiny particles (discrete phase) suspended in a liquid (continuous phase). In an oil-in-water emulsion, oil is the discrete phase, while water is the continuous phase.
What the Bancroft rule states is that contrary to common sense, what makes an emulsion oil-in-water or water-in-oil is not the relative percentages of oil or water, but which phase the emulsifier is more soluble in. So even though there may be a formula that's 60% oil and 40% water, if the emulsifier chosen is more soluble in water, it will create an oil-in-water system.
There are some exceptions to Bancroft's rule, but it's a very useful rule of thumb for most systems.
The Hydrophilic-lipophilic balance (or HLB) of a surfactant can be used in order to determine whether it's a good choice for the desired emulsion or not.
- In Oil in Water emulsions – use emulsifying agents that are more soluble in water than in oil (High HLB surfactants).
- In Water in Oil emulsions – use emulsifying agents that are more soluble in oil than in water (Low HLB surfactants).
Surfactants have 4 classifications :anionic, cationic, non-ionic, and zwitterionic.( BTW, I was wrong about it being a Zwitt. bond.)
Sodium bis(2-ethylhexyl)sulfosuccinate ( Primary in C9500a) is anionic, from what I have learned, it's a hydrogen bond.
The length of hydrogen bonds depends on bond strength, temperature, and pressure. The bond strength itself is dependent on temperature, pressure, bond angle, and environment.They can vary in strength from very weak to extremely strong.
..Then, if you read the post I put up the other day, you see there are 3 phases of oil released underwater.
Jet Phase: The speed of the oil and natural gas being expelled from the pressurized, confined space of the well into the water makes the oil form droplets and the gas form bubbles.
Plume Phase: The momentum of these tiny droplets and bubbles drags significant volumes of sea water upward into the water column, forming a plume. In deeper water, so much water is incorporated into the plume that eventually, the oil–natural gas–water mix is no longer buoyant, and the plume will become suspended at what is called the terminal layer. If heavier components sink out of the suspension, the plume may reform and begin to rise again.
Post-terminal Phase: Once the plume reaches the final terminal layer, the rise of the oil and gas to the surface is driven purely by the buoyancy of the individual droplets and bubbles.
So that gives us: 3 sizes of emulsions, 3 types of emulsion stabilities, and 3 phases for aqueous oil dispersion.
An emulsion created by cavitation is perhaps the most effective, in terms of small particles size..
From the Arisdyne website , I would recommend watching the video:
Hydrodynamic Cavitation can occur in any turbulent fluid. The turbulence produces an area of greatly reduced fluid pressure. The fluid vaporizes due to the low pressure, forming a cavity. At the edges of the cavity, small amounts of vapor break off. These form smaller cavities 100 nm to 3 mm in diameter. The smaller cavities implode under the high pressure surrounding them. This process of formation and collapse is called cavitation.
Cavitation is an enormously powerful process. Conditions in the collapsing cavity can reach 5000°C and 1000 atmospheres. The implosion takes place during the cavitation process in milliseconds, releasing tremendous energy in the form of shockwaves. The power of these waves generated by the cavitation process disrupts anything in their path.
...so that's my little bit on cavitation. On to fluid flows at high velocities.
" In some prior art Blowout Preventer (BOP) operating systems, high velocity fluid flows and low differential pressures induced vibration in the system. This vibration may result in collapse and failure of hydraulic hoses in the system. A quick dump valve has been added at or near the open port on the BOP assembly to reduce vibration and other problems. The dump valve has a vent position and an open position. Several alternative embodiments add a ball check valve assembly to the shuttle in the quick dump valve."
http://www.patents.com/F-Harold-Hollister/Richmond/TX/3128164/inventors/
I included that one so's you know it's an actual problem, and not a figment of my imagination.Thank you Mr Hollister.
(fluid mechanics) Flow of a fluid over a body at speeds greater than the speed of sound in the fluid, and in which the shock waves start at the surface of the body. Also known as supercritical flow.
Mach waves
A particle moving in a compressible medium, such as air, emits acoustic disturbances in the form of spherical waves. These waves propagate at the speed of sound (M = 1). If the particle moves at a supersonic speed, the generated waves cannot propagate upstream of the particle. The spherical waves are enveloped in a circular cone called the Mach cone. The generators of the Mach cone are called Mach lines or Mach waves.Shock waves
When a fluid at a supersonic speed approaches an airfoil (or a high-pressure region), no information is communicated ahead of the airfoil, and the flow adjusts to the downstream conditions through a shock wave. Shock waves propagate faster than Mach waves, and the flow speed changes abruptly from supersonic to less supersonic or subsonic across the wave. Similarly, other properties change discontinuously across the wave. A Mach wave is a shock wave of minimum strength. A normal shock is a plane shock normal to the direction of flow, and an oblique shock is inclined at an angle to the direction of flow. The velocity upstream of a shock wave is always supersonic. Downstream of an oblique shock, the velocity may be subsonic resulting in a strong shock, or supersonic resulting in a weak shock. The downstream velocity component normal to any shock wave is always subsonic. There is no change in the tangential velocity component across the shock.In a two-dimensional supersonic flow around a blunt body (see illustration), a normal shock is formed directly in front of the body, and extends around the body as a curved oblique shock. At a sufficient distance away, the flow field is unaffected by the presence of the body, and no discontinuity in velocity occurs. The shock then reduces to a Mach wave.
Then I found this patent from Shell.....
The separation of liquid and/or solid components from a multiphase fluid stream passing through a supersonic fluid separator is enhanced by injecting a surface active agent ( READ: SURFACTANT )into the fluid stream passing through the separator. Preferably the spray is injected via an injection tube that has a positive or negative electrical potential, whereas one of the walls of the separator housing has an opposite electrical potential, so that the injected spray and any liquid droplets and/or particles formed around the injected nuclei are induced to flow towards said electrically loaded wall.
http://www.freepatentsonline.com/7261766.html
Shocks waves form because information about conditions downstream of a point of sonic or supersonic flow can not propagate back upstream past the sonic point.
The behavior of a fluid changes radically as it starts to move above the speed of sound (in that fluid). For example, in subsonic flow, a stream tube in an accelerating flow contracts. But in a supersonic flow, a stream tube in an accelerating flow expands. To interpret this in another way, consider steady flow in a tube that has a sudden expansion: the tube's cross section suddenly widens, so the cross-sectional area increases.
In subsonic flow, the fluid speed drops after the expansion (as expected). In supersonic flow, the fluid speed increases. This sounds like a contradiction, but it isn't: the mass flux is conserved but because supersonic flow allows the density to change, the volume flux is not constant.
So the fluid passing through the wellhead would have been restricted by the partially closed blind ram, and the trapped drillpipe sections. You could call that "choking back the flow ". The following from OnePetro:
" Wellhead chokes are installed on wells to control flow rates and to protect the reservoir and surface equipment from pressure fluctuations. Flow through the choke can be described as either critical or subcritical. In the critical-flow region, the mass flow rate reaches a maximum value that is independent of the pressure drop applied across the choke. Therefore, once critical flow is reached, any dis-turbance introduced downstream of the choke will have no effect on upstream conditions. Therefore, chokes are commonly operated under critical-flow conditions to isolate the reservoir from pressure fluctuations introduced by surface processing equipment.
A second use of wellhead chokes is to monitor production rates by operating in the subcritical-flow region, especially when oil and gas are produced from offshore or hostile environments. For these applications, it is advantageous to use MOV chokes that allow the size of the choke opening to be changed while the choke is under pressure without interruption of production. With this feature, the pressure drop across the choke, and thereby manipulation of the flow rate, can be remotely controlled. Surbey et al. I discussed in detail the application of MOV chokes in the subcritical-flow region.
This investigation presents the application of MOV chokes in the critical-flow region. The limitations of conventional correlations in predicting critical-flow behavior for MOV chokes is also discussed. A new correlation is presented to predict the transition between critical and subcritical flow that is applicable to conventional chokes as well."
To end this post :
I hope since they have finally managed to bring the BOP to the surface, that there will be some closure in this matter. We could say without a doubt, that there were certainly some effects on the phases of the oil in the water that may have had something to do with what was happening at the wellhead, ie: the COREXIT products being applied, and the restrictions in the flow.
http://www.freepatentsonline.com/4011661.html
http://www.economicexpert.com/a/Compressible:flow.htm
http://encyclopedia2.thefreedictionary.com/Supersonic+flow
http://cavitronix.com/how-it-works/
http://en.wikipedia.org/wiki/Emulsify
http://en.wikipedia.org/wiki/Bancroft_rule
Thursday, September 2, 2010
" Benthic " is so ambiguous
Why it's still a mystery how dispersants work, or where the oil is, is just plain silly. I'm still waiting for the EPA to release it's test results of the secret proprietary salts in COREXIT products, I read at the Oil Drum they have begun testing.
From the National Academy of Sciences :
" The objective of dispersant use is to enhance the amount of oil that physically mixes into the water column, reducing the potential that a surface slick will contaminate shoreline habitats or come into contact with birds, marine mammals, or other organisms that exist on the water surface or shoreline. Conversely, by promoting dispersion of oil into the water column, dispersants increase the potential exposure of water-column and benthic biota to spilled oil. "
http://en.wikipedia.org/wiki/Benthic_zone
" The benthic zone is the ecological region at the lowest level of a body of water such as an ocean or a lake, including the sediment surface and some sub-surface layers. Organisms living in this zone are called benthos. They generally live in close relationship with the substrate bottom; many such organisms are permanently attached to the bottom. "
-------------------------------------------------------
Dr. Jim Clark Head of Oil Spill Research Program ... (Exxon Mobil Corporation; Head of ExxonMobil's Oil; Exxon Biomedical Sciences , Inc.) has the following to say about COREXIT products in one of his presentations, titled :
DISPERSANT BASICS : Mechanism, Chemistry, and Physics of Dispersants in Oil Spill Response.
http://www.uni-regensburg.de/Fakultaeten/nat_Fak_IV/Physikalische_Chemie/Kunz/student/Uebung_Formulierung/Clark_presentation.pdf
The following was a water tank test done in Alaska, concerning various COREXIT products, but strangely done in water with a very low salinity content, where sea application dispersants are almost singularly reliant on salt to maintain the H/B balance, this test was flawed, IMHO. Jim Clark specifically states that dispersants in low salt environments lose their effectiveness( stated in the above pdf )
Report on visit to OHMSETT to observe Exxon/MMS Cold-Water Dispersant Tests
March 5-6, 2002
http://www.pwsrcac.org/docs/d0001500.pdf
From the National Academy of Sciences :
http://en.wikipedia.org/wiki/Benthic_zone
" The benthic zone is the ecological region at the lowest level of a body of water such as an ocean or a lake, including the sediment surface and some sub-surface layers. Organisms living in this zone are called benthos. They generally live in close relationship with the substrate bottom; many such organisms are permanently attached to the bottom. "
Here's the whole article from the National academy of the Sciences.
---------------------------------------------------------------------
Approximately 3 million gallons (10,000 metric tons [tonnes]) of oil or refined petroleum product are spilled into the waters of the United States every year (NRC, 2003). This amount represents the total input from hundreds of spills, many of which necessitate timely and effective response. When these oil spills occur in the United States, the primary response methods consist of the deployment of mechanical on-water containment and recovery systems, such as booms and skimmers.
Under the Oil Pollution Act of 1990 (OPA 90), the U.S. Coast Guard (USCG) passed rules for vessel and facility response plans that specified the minimum equipment and personnel capabilities for oil containment and recovery. This requirement has significantly expanded mechanical response capability above that which existed in 1989 at the time of Tanker Vessel (T/V) Exxon Valdez spill (the event that led to passage of OPA 90). Mechanical recovery, however, is not always sufficient because conditions at the spill are often outside of the effective operating conditions of the equipment. OPA 90 also called for national and regional response teams to develop guidelines to address the use of other on-water response strategies, specifically the use of chemical dispersants and in-situ burning.
Throughout the Unites States, many regional response teams have identified zones where dispersants and in-situ burning are “pre-approved” for use. This pre-approval means that the response and re-
source agencies have determined that the Federal On-Scene Coordinator has the authority, as outlined under the pre-approval definitions, to decide to use dispersants without additional consultation. In general, these pre-approval zones are in waters beyond 3 nautical miles (nm; roughly 5 kilometers [km]) of the shoreline and in water depths greater than 30 feet (10 meters). Even with establishment of these pre-approval zones, dispersant use has been infrequent, in part reflecting the difficulty of mobilizing available equipment and dispersants within a narrow window of opportunity in which they can be effective. In areas where dispersants are not often considered, it takes more time to identify, contract, and mobilize the specialized resources needed for dispersant application.
To address the concerns regarding requisite equipment and personnel capabilities, the U.S. Coast Guard in 2002 proposed changes to the oil spill contingency planning regulations measuring the minimum capabilities for dispersant application in all pre-approved zones within acceptable time frames. With implementation of the regulations, dispersant application resources will become more readily available. The potential, therefore, for using dispersants in nearshore and shallow waters, when appropriate, will increase as well.
Oil spill dispersants do not actually reduce the total amount of oil entering the environment. Rather, they change the inherent chemical and physical properties of oil, thereby changing the oil’s transport, fate, and potential effects. Small amounts of spilled oil naturally disperse into the water column, through the action of waves and other environmental processes. The objective of dispersant use is to enhance the amount of oil that physically mixes into the water column, reducing the potential that a surface slick will contaminate shoreline habitats or come into contact with birds, marine mammals, or other organisms that exist on the water surface or shoreline. Conversely, by promoting dispersion of oil into the water column, dispersants increase the potential exposure of water-column and benthic biota to spilled oil. Dispersant application thus represents a conscious decision to increase the hydrocarbon load (resulting from a spill) on one component of the ecosystem (e.g., the water column) while reducing the load on another (e.g., coastal wetland). Decisions to use dispersants, therefore, involve trade-offs between decreasing the risk to water surface and shoreline habitats while increasing the potential risk to organisms in the water column and on the seafloor. This trade-off reflects the complex interplay of many variables, including the type of oil spilled, the volume of the spill, sea state and weather, water depth, degree of turbulence (thus mixing and dilution of the oil), and relative abundance and life stages of resident organisms.
Each spill is a unique event that unfolds over a variety of time scales. Properties of petroleum hydrocarbons immediately start to change when spilled onto water. This natural “weathering” makes the oil more difficult to disperse through time; consequently, the window of opportunity for effective dispersant application is early, usually within hours to 1–2 days after a release under most conditions, though there are exceptions. The decision to apply dispersants is thus time sensitive and complex. Given the potential impacts that dispersed oil may have on water-column and seafloor biota and habitats, thoughtful analysis is required prior to the spill event so that decisionmakers understand the potential impacts with and without dispersant application. Thus, decisionmaking regarding the use of dispersants falls into two broad temporal categories: (1) before the event during spill contingency planning; and (2) shortly after the initial event, generally within the first 12 to 48 hours.
In recognition of the increased potential to use dispersants in a variety of settings, the Minerals Management Service (MMS), the National Oceanic and Atmospheric Administration (NOAA), the USCG, and the American Petroleum Institute (API) asked the National Academies to form a committee of experts to review the adequacy of existing information and ongoing research regarding the efficacy and effects of dispersants as an oil spill response technique in the United States.2 Emphasis was placed on understanding the limitations imposed by the various methods used in these studies and on recommending steps that should be taken to better understand the efficacy of dispersant use and the effect of dispersed oil on freshwater, estuarine, and marine environments. Specifically, the committee’s task was to:
- review and evaluate ongoing research and existing literature on dispersant use (including international studies) with emphasis on (a) factors controlling dispersant effectiveness (e.g., environmental conditions, dispersant application vehicles and strategies, and oil properties, particularly as the spilled oil weathers), (b) the short- and long-term fate of chemically or naturally dispersed oil, and (c) the toxicological effects of chemically and naturally dispersed oil;
- evaluate the adequacy of the existing information about dispersants to support risk-based decisionmaking on response options for a variety of spatially and temporally defined oil spills;
- recommend steps that should be taken to fill existing knowledge gaps, with emphasis to be placed on how laboratory and mesoscale ex-periments could inform potential controlled field trials and what experimental methods are most appropriate for such tests.
| 2 | A similar request was put to the National Academies in the mid 1980s, leading to the publication of the 1989 NRC report Using Oil Spill Dispersants on the Sea. The current report is not truly an update of the 1989 report, as it selectively revisits some topics while including discussions on issues that have emerged since that time. Many readers may, therefore, find the assessments and summaries in Using Oil Spill Dispersants on the Sea of value. |
OVERARCHING CHALLENGE TO EFFECTIVE DECISION MAKING
In general, the information base used by decision makers dealing with spills in areas where the consequences of dispersant use are fairly straightforward has been adequate (for example, situations where rapid dilution has the potential to reduce the possible risk to sensitive habitat enough to allow the establishment of pre-approval zones). Many of the technical issues raised in this report, however, deal with settings where greater confidence is needed to make effective decisions regarding potential benefits or adverse impacts associated with dispersant use. In many instances where a dispersed plume may come into contact with sensitive water-column or benthic organisms and populations, the current understanding of key processes and mechanisms is inadequate to confidently support a decision to apply dispersants. Thus, such decisions regarding the potential use of dispersants in nearshore settings are creating a demand for additional information.
Research funds in the United States to support oil spill response options in general are extremely limited and declining (the total amount is less than $10 million annually). Consequently, despite the complex and numerous variables involved in risk-based decisionmaking regarding the potential use of dispersants, efforts to fill knowledge gaps must be thoroughly grounded in the recognition that no amount of research or environmental monitoring will eliminate uncertainty entirely. Failure to make a timely decision regarding dispersant application is in actuality a decision not to use dispersants, and in some instances may place some natural resources at an increased and unnecessary risk. Given the limited funding available to carry out needed research in this area, it is particularly important that research be carried out as efficiently as possible and that the research process focuses on efforts that result in sound, reproducible results that support decisionmaking. In many instances, efforts to reduce experimental complexity to ensure reproducibility or to secure cost savings have led to results that have very limited utility for making decisions in natural settings. NOAA, the Environmental Protection Agency (EPA), the Department of the Interior (including MMS and U.S. Geological Survey), USCG, relevant state agencies, industry, and appropriate international partners should work together to establish an integrated research plan which focuses on collecting and disseminating peer-reviewed information about key aspects of dispersant use in a scientifically robust, but environmentally meaningful context.
-------------------------------------------------------
Dr. Jim Clark Head of Oil Spill Research Program ... (Exxon Mobil Corporation; Head of ExxonMobil's Oil; Exxon Biomedical Sciences , Inc.) has the following to say about COREXIT products in one of his presentations, titled :
DISPERSANT BASICS : Mechanism, Chemistry, and Physics of Dispersants in Oil Spill Response.
http://www.uni-regensburg.de/Fakultaeten/nat_Fak_IV/Physikalische_Chemie/Kunz/student/Uebung_Formulierung/Clark_presentation.pdf
The following was a water tank test done in Alaska, concerning various COREXIT products, but strangely done in water with a very low salinity content, where sea application dispersants are almost singularly reliant on salt to maintain the H/B balance, this test was flawed, IMHO. Jim Clark specifically states that dispersants in low salt environments lose their effectiveness( stated in the above pdf )
Report on visit to OHMSETT to observe Exxon/MMS Cold-Water Dispersant Tests
March 5-6, 2002
http://www.pwsrcac.org/docs/d0001500.pdf
Wednesday, August 25, 2010
Emulsifying oil at the wellhead ?
Something I have been thinking about, in light of all the effort to find the oil.
First, a little bit about how deepwater spills normally behave.There are 3 phases known.
Jet Phase: The speed of the oil and natural gas being expelled from the pressurized, confined space of the well into the water makes the oil form droplets and the gas form bubbles.
Plume Phase: The momentum of these tiny droplets and bubbles drags significant volumes of sea water upward into the water column, forming a plume. In deeper water, so much water is incorporated into the plume that eventually, the oil–natural gas–water mix is no longer buoyant, and the plume will become suspended at what is called the terminal layer. If heavier components sink out of the suspension, the plume may reform and begin to rise again.
Post-terminal Phase: Once the plume reaches the final terminal layer, the rise of the oil and gas to the surface is driven purely by the buoyancy of the individual droplets and bubbles.
---------------
Some thing I was curious about after reading a little bit on multiphase fluids. Would the effects of turbidity introduced into the fluid at the area it was being released in have any effect on how gas was released from the fluid ? I was wondering if it were possible that a slight emulsion was happening as the fluids were being forced past the obstructions in the BOP at HT/HP.
The other thing I was curious about is if it's possible that the gas that went into solute ( methane ) could have effectively slightly lowered the overall density of the water in the area ?
...these were two questions posed at the Oil Drum to someone who works in the oil business, his answer ?
http://www.theoildrum.com/node/6883
The following is a study done on water density and bouyancy factors when gas releases from the ocean floor happen. This study was done specifically for the deepwater drilling industry.
http://etd.lib.ttu.edu/theses/available/etd-09152009-31295005266308/unrestricted/31295005266308.pdf
Something I have been reading a great deal about is ultrasonic emulsifications and how they are formed, reasons being, sonar usage in the area , but also how cavitation can be produced in different ways, such as Venturi nozzles, high pressure nozzles, high velocity rotation, or ultrasonic transducers ( Which were used to measure flow rates through the BOP stack, no ? Why they would have to be placed all the way around the flex joint to measure flow is beyond me, for it seems it does not take more than one or two to measure flow rates, and I know I saw way more than that ). I realize the aperture would ot be so much considered a traditional Venturi tube , but the principle in my mind is the same, flow travels in large area, constricted to a smaller area, and back out again to a larger area.
Also, the process with ultrasound is done with surfactants that are added into the fluid.
Anyway, I ask those of you willing, to venture into the twilight zone,...no wait,.. 'slaps forehead'....what I meant to say, is " will you read this webpage ?"
Very important you read the entire page and understand what it says...
http://www.hielscher.com/ultrasonics/emulsify_01.htm
Then another thought/brain-stretcher
Cathodic protection of the BOP stack, and the possibility of electrical emulsification/slight emulsification aided by ""( I know , I reaching here, I'm bored. )
Sonication is used to disrupt biological membranes of bacteria by exposing them to high frequency sound waves.
From what I can find so far, most ROV sonar seems to be around 650-700Khz, but then there are different types of sonar, ie, things like dual beam and dual frequency sonars.
High Frequency: typically less than five nautical miles.
Mid Frequency: typical ranges of 1-10 nautical miles.
Low Frequency: ranges up to 100 nautical miles
Sealion 3000 Deepwater Work Class ROV
http://www.rovtech.co.uk/downloads/ROV_Sealion3000_Jan07.pdf
I would be interested to know about the transducers they used on the stack, purely out of dense-headed curiosity.
A little bonus paper :
http://www.netl.doe.gov/technologies/oil-gas/publications/Storage/Sonica...
It's all about the groovy vibes........man. ...Here's another paper that illustrates what I am talking about.
ULTRASONIC PRODUCTION OF NANO-SIZE DISPERSIONS AND EMULSIONS
http://hal.archives-ouvertes.fr/docs/00/16/69/96/PDF/1048.pdf
....hhhmm....I am going to continue to research this, I have a feeling that , like usual, there is more than what's meets the eye.
Another grand conspiracy theory.
Was BP emulsifying oil at the wellhead on purpose to hide it ?
First, a little bit about how deepwater spills normally behave.There are 3 phases known.
Jet Phase: The speed of the oil and natural gas being expelled from the pressurized, confined space of the well into the water makes the oil form droplets and the gas form bubbles.
Plume Phase: The momentum of these tiny droplets and bubbles drags significant volumes of sea water upward into the water column, forming a plume. In deeper water, so much water is incorporated into the plume that eventually, the oil–natural gas–water mix is no longer buoyant, and the plume will become suspended at what is called the terminal layer. If heavier components sink out of the suspension, the plume may reform and begin to rise again.
Post-terminal Phase: Once the plume reaches the final terminal layer, the rise of the oil and gas to the surface is driven purely by the buoyancy of the individual droplets and bubbles.
---------------
Some thing I was curious about after reading a little bit on multiphase fluids. Would the effects of turbidity introduced into the fluid at the area it was being released in have any effect on how gas was released from the fluid ? I was wondering if it were possible that a slight emulsion was happening as the fluids were being forced past the obstructions in the BOP at HT/HP.
The other thing I was curious about is if it's possible that the gas that went into solute ( methane ) could have effectively slightly lowered the overall density of the water in the area ?
...these were two questions posed at the Oil Drum to someone who works in the oil business, his answer ?
http://www.theoildrum.com/node/6883
" isaac,
2 good questions and I'm afraid I don't know the answer to either!
I'd guess for the second one that the impact on the bulk density of the water would be minimal. I've taken lots of water samples before from the water legs that underlie gas reservoirs. They are often saturated with methane (and other HCs) and we flash the gas out of the samples at atmospheric conditions and check on compositions. The gas liquid ratios are usually tiny, and the density change not measurable. "
2 good questions and I'm afraid I don't know the answer to either!
I'd guess for the second one that the impact on the bulk density of the water would be minimal. I've taken lots of water samples before from the water legs that underlie gas reservoirs. They are often saturated with methane (and other HCs) and we flash the gas out of the samples at atmospheric conditions and check on compositions. The gas liquid ratios are usually tiny, and the density change not measurable. "
The following is a study done on water density and bouyancy factors when gas releases from the ocean floor happen. This study was done specifically for the deepwater drilling industry.
http://etd.lib.ttu.edu/theses/available/etd-09152009-31295005266308/unrestricted/31295005266308.pdf
Something I have been reading a great deal about is ultrasonic emulsifications and how they are formed, reasons being, sonar usage in the area , but also how cavitation can be produced in different ways, such as Venturi nozzles, high pressure nozzles, high velocity rotation, or ultrasonic transducers ( Which were used to measure flow rates through the BOP stack, no ? Why they would have to be placed all the way around the flex joint to measure flow is beyond me, for it seems it does not take more than one or two to measure flow rates, and I know I saw way more than that ). I realize the aperture would ot be so much considered a traditional Venturi tube , but the principle in my mind is the same, flow travels in large area, constricted to a smaller area, and back out again to a larger area.
Also, the process with ultrasound is done with surfactants that are added into the fluid.
Anyway, I ask those of you willing, to venture into the twilight zone,...no wait,.. 'slaps forehead'....what I meant to say, is " will you read this webpage ?"
Very important you read the entire page and understand what it says...
http://www.hielscher.com/ultrasonics/emulsify_01.htm
Then another thought/brain-stretcher
Cathodic protection of the BOP stack, and the possibility of electrical emulsification/slight emulsification aided by ""( I know , I reaching here, I'm bored. )
Sonication is used to disrupt biological membranes of bacteria by exposing them to high frequency sound waves.
From what I can find so far, most ROV sonar seems to be around 650-700Khz, but then there are different types of sonar, ie, things like dual beam and dual frequency sonars.
High Frequency: typically less than five nautical miles.
Mid Frequency: typical ranges of 1-10 nautical miles.
Low Frequency: ranges up to 100 nautical miles
Sealion 3000 Deepwater Work Class ROV
http://www.rovtech.co.uk/downloads/ROV_Sealion3000_Jan07.pdf
I would be interested to know about the transducers they used on the stack, purely out of dense-headed curiosity.
A little bonus paper :
http://www.netl.doe.gov/technologies/oil-gas/publications/Storage/Sonica...
It's all about the groovy vibes........man. ...Here's another paper that illustrates what I am talking about.
ULTRASONIC PRODUCTION OF NANO-SIZE DISPERSIONS AND EMULSIONS
http://hal.archives-ouvertes.fr/docs/00/16/69/96/PDF/1048.pdf
....hhhmm....I am going to continue to research this, I have a feeling that , like usual, there is more than what's meets the eye.
Another grand conspiracy theory.
Was BP emulsifying oil at the wellhead on purpose to hide it ?
Raman would be proud...I think.
How awesome, a perfect timely example of what I wrote about a few days ago.
Thank you " Official Science Team " .I'm sure the engineers, ROV operators and science team members are having a good laugh right now over the hysteria this video will produce...I know I am.
Thank you " Official Science Team " .I'm sure the engineers, ROV operators and science team members are having a good laugh right now over the hysteria this video will produce...I know I am.
Monday, August 23, 2010
Missing Mass, ...no...not that kind of Mass.
....Seems I might have stirred up the pot with my questions at the Oil Drum website about the physicality of removing the drill pipe from the well....and the displacement of mass.... I'm going to include a few questions and answers from the site,....
http://www.theoildrum.com/node/6879
Isaac,
The well is open to the sea at the moment - it is not balanced with mud but sealed with 5000 feet of cement.
They slowly dropped the pressure during the negative test. When they initially had the well balanced that was with the column of mud up to sea-level and BOP was at about 4200psi but they are now right down to ambient at 2188 psi with the well open to seawater. If there was an open flow path then we would know fairly quickly :)
![[-]](https://lh3.googleusercontent.com/blogger_img_proxy/AEn0k_sgtivZOCjhHvRULHlXCCtB_CmC4OnN0xDd4KTytgD1yg8z-7Gprgbla0D02x9a9Ay9Ep78j5GdM_XrUQ_hd1PBFGe1YkLiFu6GStQPorkStanDlmxA308=s0-d)
That's not what I am asking about, but thank you anyway.
Isaac:
Yes, the mud level in the well will go down as the pipe is pulled, and that volume will be replaced by seawater, since the well is currently open to the sea at the top.
The key is, it doesn't matter. You could replace the entire 8000' down to the cement with seawater, and even then no oil would flow because the 5000' of cement would hold it in, as it has been for several days now ever since they started that near-ambient testing stuff.
Gas drifting "up through the strata, and back into the wellbore"? Anything's possible, I guess. Well, up to when they started the near-ambient testing, anyway. But the pressure DECREASE observed (due to leakage out of the stack) pretty well put that scenario out of the picture. Then when they went to exactly ambient and closed all the valves, they had no pressure change for 48 hours.
Frank
Thanks Geek, jes' what I was thimking. I would pump mud INTO the top of the DP to provide the replaced mass at the bottom, but I am looking at this with the eyes of an industry outsider, so it's probably not even possible. I still don't understand how you pump mud into the BOP stack through the choke line(?)with the valves in the top of the cap open ( to remove the DP at the same time ) don't they have to have the system closed in order to pump the mud...? Usually in this event the path of least resistance for the mud would be down the bore, as it has no other place to flow.
...................at that point in the thread, there were no more responses....but it seems I got some people thinking about some things........so....further down the thread, somebody poses the same question I had asked earlier .....
..............actually...." We "...didn't conclude anything, white man.
..........at this point, one of the Oil Drum posters , David E. Brown, was nice enough to have typed up a nice little synopsis....and included this little gem :
" While drawing our the old drill string, which is hollow, and therefore will be less likely to create any significant suction effect, at the speeds at which they will extract it, they can replace its weight with mud via the choke and/or kill lines which are attached below the rams. "
...........at this point, I began to start to question reality, let's check out some of the responses.
David, very good synopsis. There is one technical blooper, however.
"While drawing our the old drill string, which is hollow, and therefore will be less likely to create any significant suction effect, at the speeds at which they will extract it, they can replace its weight with mud via the choke and/or kill lines which are attached below the rams."
Actually, as the drill pipe is removed, it will be an equivalent volume of the pipe that is replaced rather than the weight of the pipe. Normally, the density of the replaced fluid is equivalent to that which is already in the well and which has demonstrated to be sufficient to hold back the pressure from below.
Good summary though.
If the pipe is well crimped it may lift mud up inside it as well.
EDM, if the drill pipe is hanging, it isn't contributing any weight to the mud column, so nothing needs to be replaced, right?
...........so then the thread closed..........but then, today's thread.....
.....well....interesting,.....I like the fact that the "Rockman" is willing to think a little...I'd like to examine the statement from his last post, not to drag him through the mud either.
" I think the DP wouldn't add anything to the effective mud weight. Just like hanging a lead weight in a glass of water: doesn't make the glass any heavier. The weight of the DP is being transferred to the BOP and not the bottom of the hole IMHO. "
.........actually, just for a simple experiment, because I doubt the truth of that statement , I took a digital scale, and a small plastic container filled with water, weighed the total, and displaced some fluid by immersing the end of an X-acto knife.
What I observe.....actually, once the mass is added, it becomes part of the total weight in the fluid.
........so again that leaves me with the question I originally asked.
" How do you remove the drill pipe and replace the missing mass with mud at the same time ? "
.....In my little brain, I see an easy way to remove the drillpipe, simply by pumping the mud down through the top of the pipe so the mud mass will be deposited at the bottom and will replace the mass removed (drillpipe) at exactly the same time.
.......that's if they can actually get the new cap to function correctly....>facepalm<
....that's all for now, I'm off to do some math-n-sh*t.
http://www.theoildrum.com/node/6879
How do you remove the drill pipe and replace the missing mass with mud at the same time ?
If the the pressure in the wellbore is currently at an equalibrium, nothings leaking, when they pull the pipe out, wouldn't seawater start to go down the wellbore ?
How do you pump mud and guarantee it will go down and not up ?
...also...is it possible for gas to drift from the reservoir, up through the strata, and back into the wellbore at a higher point ? I understand that if it's at an equilibrium, nothing can move either way...but if the bore does not have 100% structural integrity of the outer cement and casings, and the inside of the bore were to become underpressured against the surrounding formation by removing said mass (DP)...'looks at floor'....
...I'm gonna go tighten my neck-bolts for a spell.
If the the pressure in the wellbore is currently at an equalibrium, nothings leaking, when they pull the pipe out, wouldn't seawater start to go down the wellbore ?
How do you pump mud and guarantee it will go down and not up ?
...also...is it possible for gas to drift from the reservoir, up through the strata, and back into the wellbore at a higher point ? I understand that if it's at an equilibrium, nothing can move either way...but if the bore does not have 100% structural integrity of the outer cement and casings, and the inside of the bore were to become underpressured against the surrounding formation by removing said mass (DP)...'looks at floor'....
...I'm gonna go tighten my neck-bolts for a spell.
Isaac,
The well is open to the sea at the moment - it is not balanced with mud but sealed with 5000 feet of cement.
"it is not balanced with mud but sealed with 5000 feet of cement."
Yes, I understand that( I was under the impression that there is a leg of mud on top of that as well 5k' of seawater :), what I don't understand is how you remove mass from an area and add it at the same time without causing a differential in pressure. Are they going to remove the stuck pipe at the same time they are pumping mud..? I know it's a completely different scenario, but pulling a pipe stuck in mud creates suction/vacuum energy, the Casimir effect, which creates a negative pressure . Then there is the question of the mud and if its gelled inside the DP, wouldn't pulling that up also create negative pressure downhole( unless the force exerted by the water column above was sufficient to break the mud free when they started to pull up ) ? This is all very interesting in terms of fluid dynamics. Thanks again TOD, for taking the time to answer my " whacko" questions.
Yes, I understand that( I was under the impression that there is a leg of mud on top of that as well 5k' of seawater :), what I don't understand is how you remove mass from an area and add it at the same time without causing a differential in pressure. Are they going to remove the stuck pipe at the same time they are pumping mud..? I know it's a completely different scenario, but pulling a pipe stuck in mud creates suction/vacuum energy, the Casimir effect, which creates a negative pressure . Then there is the question of the mud and if its gelled inside the DP, wouldn't pulling that up also create negative pressure downhole( unless the force exerted by the water column above was sufficient to break the mud free when they started to pull up ) ? This is all very interesting in terms of fluid dynamics. Thanks again TOD, for taking the time to answer my " whacko" questions.
They slowly dropped the pressure during the negative test. When they initially had the well balanced that was with the column of mud up to sea-level and BOP was at about 4200psi but they are now right down to ambient at 2188 psi with the well open to seawater. If there was an open flow path then we would know fairly quickly :)
That's not what I am asking about, but thank you anyway.
Isaac:
Yes, the mud level in the well will go down as the pipe is pulled, and that volume will be replaced by seawater, since the well is currently open to the sea at the top.
The key is, it doesn't matter. You could replace the entire 8000' down to the cement with seawater, and even then no oil would flow because the 5000' of cement would hold it in, as it has been for several days now ever since they started that near-ambient testing stuff.
Gas drifting "up through the strata, and back into the wellbore"? Anything's possible, I guess. Well, up to when they started the near-ambient testing, anyway. But the pressure DECREASE observed (due to leakage out of the stack) pretty well put that scenario out of the picture. Then when they went to exactly ambient and closed all the valves, they had no pressure change for 48 hours.
Frank
I'm not a expert, but I think I have an explanation:
The fishing tool is put down into the top of the second, new BOP that was kludged onto the top of the BOP that is wanted for evidence. To do this 'put down into ...' the tool is attached to the bottom end of a new string of drill pipe. This attachment is sturdy enough that the 'bad, broken' drill pipe can be lifted out of the well once the fishing tool is firmly connected to it. The strength of this attachment can be tested by pulling on the top end of new string of drill pipe from up on the drill ship. There, they can measure force of lifting of the crane that is holding the new drill pipe. If they can't develop enough force to lift an extra 3000' of drill pipe, they huddle and come up with a planB, otherwise they are ready to try to open the shear rams in the BOP (that they think are what is holding the bad, broken drill pipe and keeping it from falling deep into the well). If the get the shear ram open, which they should do --slowly-- so that
the weight of the bad broken drill pipe shifts from the shear ram over to the new string gradually, THEN they can start drawing the bad, broken drill pipe out of the well --SLOWLY--. This is the first time in the process when they have to start replacing the volume of the bad, broken drill pipe with something that is heavier than seawater.
This replacement material is, I think, what concerns you:
What to use as replacement material? Solid, liquid, or gas? I guess a liquid. A solid would get in the way of pulling the bad, broken pipe up and out. A gas is an option that a physicist, like me, would even mention. So their only option is a liquid, like mud. It is heavy and it can be made to flow downward by suitable application of gravity.
The fishing tool is mechanically connected to both the good new pipe string and the bad, broken pipe, BUT it is not a pipe fitting. Mud can be pumped down from the drill ship inside the the good new pipe string. Enough new mud can be pumped to flood the region around the fish tool so that it is immersed in mud. (Now they can't any longer see what they are doing, because mud is opaque. But they are probably doing this without downhole cameras, anyway.) They an determine the depth of mud in this flooding by measuring the pressure differential between the inside of the BOP and the surrounding seawater. They pull the string of bad, broken pipe and good, new pipe up. As they do this, the level of the top of the mud should go down to replace the volume of pipe that is coming up out of the mud. This should be done during the first few inches of upward motion of the combined pipe string. If there is numerical agreement of pipe string upward motion with mud level downward motion, they can continue --- add mud to keep the mud level above the top of the BOP, but not spilling out of the top and the top the top of that that other, now structure that they stacked on top of the BOP. AND keep track of mud volume pumped. And plot the data as they gather it. Make sure mud level and volume track the upward motion of drill string, psi by psi and cuft by cuft against pipe travel inch by inch.
My major problem with this is that I am convinced that BP managers are intellectually incapable of handling this level of sophistication in process. Or if they are capable, they perceive that it is to their advantage to pretend otherwise.
Not covered are issues relating to the possibility that bad, broken pipe is stuck in the cement that is being used to kill the well. Pulling it out of the cement would introduce cracks. Mud would have had no problems with cracking. Also, I have ignored all complications having to do with elastic nature of pipe, steel cable, etc.
The fishing tool is put down into the top of the second, new BOP that was kludged onto the top of the BOP that is wanted for evidence. To do this 'put down into ...' the tool is attached to the bottom end of a new string of drill pipe. This attachment is sturdy enough that the 'bad, broken' drill pipe can be lifted out of the well once the fishing tool is firmly connected to it. The strength of this attachment can be tested by pulling on the top end of new string of drill pipe from up on the drill ship. There, they can measure force of lifting of the crane that is holding the new drill pipe. If they can't develop enough force to lift an extra 3000' of drill pipe, they huddle and come up with a planB, otherwise they are ready to try to open the shear rams in the BOP (that they think are what is holding the bad, broken drill pipe and keeping it from falling deep into the well). If the get the shear ram open, which they should do --slowly-- so that
the weight of the bad broken drill pipe shifts from the shear ram over to the new string gradually, THEN they can start drawing the bad, broken drill pipe out of the well --SLOWLY--. This is the first time in the process when they have to start replacing the volume of the bad, broken drill pipe with something that is heavier than seawater.
This replacement material is, I think, what concerns you:
What to use as replacement material? Solid, liquid, or gas? I guess a liquid. A solid would get in the way of pulling the bad, broken pipe up and out. A gas is an option that a physicist, like me, would even mention. So their only option is a liquid, like mud. It is heavy and it can be made to flow downward by suitable application of gravity.
The fishing tool is mechanically connected to both the good new pipe string and the bad, broken pipe, BUT it is not a pipe fitting. Mud can be pumped down from the drill ship inside the the good new pipe string. Enough new mud can be pumped to flood the region around the fish tool so that it is immersed in mud. (Now they can't any longer see what they are doing, because mud is opaque. But they are probably doing this without downhole cameras, anyway.) They an determine the depth of mud in this flooding by measuring the pressure differential between the inside of the BOP and the surrounding seawater. They pull the string of bad, broken pipe and good, new pipe up. As they do this, the level of the top of the mud should go down to replace the volume of pipe that is coming up out of the mud. This should be done during the first few inches of upward motion of the combined pipe string. If there is numerical agreement of pipe string upward motion with mud level downward motion, they can continue --- add mud to keep the mud level above the top of the BOP, but not spilling out of the top and the top the top of that that other, now structure that they stacked on top of the BOP. AND keep track of mud volume pumped. And plot the data as they gather it. Make sure mud level and volume track the upward motion of drill string, psi by psi and cuft by cuft against pipe travel inch by inch.
My major problem with this is that I am convinced that BP managers are intellectually incapable of handling this level of sophistication in process. Or if they are capable, they perceive that it is to their advantage to pretend otherwise.
Not covered are issues relating to the possibility that bad, broken pipe is stuck in the cement that is being used to kill the well. Pulling it out of the cement would introduce cracks. Mud would have had no problems with cracking. Also, I have ignored all complications having to do with elastic nature of pipe, steel cable, etc.
Thanks Geek, jes' what I was thimking. I would pump mud INTO the top of the DP to provide the replaced mass at the bottom, but I am looking at this with the eyes of an industry outsider, so it's probably not even possible. I still don't understand how you pump mud into the BOP stack through the choke line(?)with the valves in the top of the cap open ( to remove the DP at the same time ) don't they have to have the system closed in order to pump the mud...? Usually in this event the path of least resistance for the mud would be down the bore, as it has no other place to flow.
...................at that point in the thread, there were no more responses....but it seems I got some people thinking about some things........so....further down the thread, somebody poses the same question I had asked earlier .....
ROCKMAN, wondering if you could field a couple questions before this thread closes? Already posted upthread, but no responses yet:
1) Following up on the thread you started about the suspect positive pressure test: would it have been possible for a bad cement job (and lax mud return monitoring) to result in the original bottom hole cement plugs getting slowly pushed up the 7 inch casing during the seawater displacement until they hit the 9 7/8 transition at which point all h*ll started breaking loose?
2) regarding the question about the effect of pulling the old drill pipe out of the WW, if the drill pipe is hanging, it isn't contributing any weight to the mud column, so nothing needs to be replaced as it is removed, right?
Thanks, I'll eat some BB for you this week, butter pecan maybe.
1) Following up on the thread you started about the suspect positive pressure test: would it have been possible for a bad cement job (and lax mud return monitoring) to result in the original bottom hole cement plugs getting slowly pushed up the 7 inch casing during the seawater displacement until they hit the 9 7/8 transition at which point all h*ll started breaking loose?
2) regarding the question about the effect of pulling the old drill pipe out of the WW, if the drill pipe is hanging, it isn't contributing any weight to the mud column, so nothing needs to be replaced as it is removed, right?
Thanks, I'll eat some BB for you this week, butter pecan maybe.
2) The DP is displacing mud. AS the DP is raised the mud level will fall so the pressure created by the mud will fall. If they want to keep the well balanced they need to add mud.
Mixed up some Gatorade the other day. I do it with weighed powder then stir it in. I had the jug of water on the scale and I got curious as to what effect raising or lowering the spoon, in the liquid, would have (you can try this at home). Lower the spoon without touching the bottom or sides the weight increased, lift the spoon and the weight decreased. Now anyone tell me why? ;) I guess the DP will act the same as well as the change in mud level.
NAOM, thanks. For no good reason I forgot about displacement and the difference between mud weight and mud pressure.
What I didn't think of at all was the buoyancy of the drill pipe in the mud, or of a spoon in Gatorade. The weight of the pipe hanging from the BOP is reduced by the buoyancy of the steel in liquid mud. So if you put a scale in the bottom of your Gatorade jug and set the spoon on it, it would read less than it would in air. Nice riddle, thanks again.
Mixed up some Gatorade the other day. I do it with weighed powder then stir it in. I had the jug of water on the scale and I got curious as to what effect raising or lowering the spoon, in the liquid, would have (you can try this at home). Lower the spoon without touching the bottom or sides the weight increased, lift the spoon and the weight decreased. Now anyone tell me why? ;) I guess the DP will act the same as well as the change in mud level.
NAOM, thanks. For no good reason I forgot about displacement and the difference between mud weight and mud pressure.
What I didn't think of at all was the buoyancy of the drill pipe in the mud, or of a spoon in Gatorade. The weight of the pipe hanging from the BOP is reduced by the buoyancy of the steel in liquid mud. So if you put a scale in the bottom of your Gatorade jug and set the spoon on it, it would read less than it would in air. Nice riddle, thanks again.
Didn't we conclude that for the well to be balanced, the mud column had to continue some distance up the choke/kill line above the BOP?
Why are people still talking about balance when there's a 5000' cement plug in place? It's not the mud, it's the PLUG that is controlling the well now, isn't it?
Frank
Why are people still talking about balance when there's a 5000' cement plug in place? It's not the mud, it's the PLUG that is controlling the well now, isn't it?
Frank
..............actually...." We "...didn't conclude anything, white man.
..........at this point, one of the Oil Drum posters , David E. Brown, was nice enough to have typed up a nice little synopsis....and included this little gem :
" While drawing our the old drill string, which is hollow, and therefore will be less likely to create any significant suction effect, at the speeds at which they will extract it, they can replace its weight with mud via the choke and/or kill lines which are attached below the rams. "
...........at this point, I began to start to question reality, let's check out some of the responses.
David, very good synopsis. There is one technical blooper, however.
"While drawing our the old drill string, which is hollow, and therefore will be less likely to create any significant suction effect, at the speeds at which they will extract it, they can replace its weight with mud via the choke and/or kill lines which are attached below the rams."
Actually, as the drill pipe is removed, it will be an equivalent volume of the pipe that is replaced rather than the weight of the pipe. Normally, the density of the replaced fluid is equivalent to that which is already in the well and which has demonstrated to be sufficient to hold back the pressure from below.
Good summary though.
Thanks.
That's an oops, big time - physics .00001- Archimedes, if I remember correctly.
Unfortunately I've forgotten more of my two years of engineering than I ever knew.
Now why did I switch to liberal studies (whatever that is - I've never been too sure)?
Thanks again.
That's an oops, big time - physics .00001- Archimedes, if I remember correctly.
Unfortunately I've forgotten more of my two years of engineering than I ever knew.
Now why did I switch to liberal studies (whatever that is - I've never been too sure)?
Thanks again.
If the pipe is well crimped it may lift mud up inside it as well.
EDM, if the drill pipe is hanging, it isn't contributing any weight to the mud column, so nothing needs to be replaced, right?
OB, you still have to replace the volume of the steel in the drill pipe as you pull it out of the hole. Otherwise the level of mud in the hole would decrease and the hydrostatic head would be reduced.
If you can remember back in the day when you went to the rigs with your dad, every few stands tripping out of the hole the driller would kick the pump in to fill the hole though what is called the fillup line. Before starting out of the hole they would close the standpipe valve and open the fillup line valve..
If you can remember back in the day when you went to the rigs with your dad, every few stands tripping out of the hole the driller would kick the pump in to fill the hole though what is called the fillup line. Before starting out of the hole they would close the standpipe valve and open the fillup line valve..
...........so then the thread closed..........but then, today's thread.....
brat - Just my guess but with an 11,900 psi pressure on the bottom side of the plug/shoe and a bad cmt job between it and the reservoir it would seem very possible to blow the plug/shoe out once they displaced and lost the head. I believe they tested the plug/shoe to 8,500 psi but that was pushing down from the top so I don't think that tells us anything about the stability of the system being pushed from the bottom.
I think the DP wouldn't add anything to the effective mud weight. Just like hanging a lead weight in a glass of water: doesn't make the glass any heavier. The weight of the DP is being transferred to the BOP and not the bottom of the hole IMHO.
As naom says the DP removal will require that volume to be replaced. If they pull the DP the cap will have to be open so I suspect it will be done with sea water.
As far as being balanced others have noted that with the cmt in place a balanced mud colume is required to keep the well from flowing. OTOH that's also what BP thought when they displaced the mud with sea water.
And they were wrong.
I think the DP wouldn't add anything to the effective mud weight. Just like hanging a lead weight in a glass of water: doesn't make the glass any heavier. The weight of the DP is being transferred to the BOP and not the bottom of the hole IMHO.
As naom says the DP removal will require that volume to be replaced. If they pull the DP the cap will have to be open so I suspect it will be done with sea water.
As far as being balanced others have noted that with the cmt in place a balanced mud colume is required to keep the well from flowing. OTOH that's also what BP thought when they displaced the mud with sea water.
And they were wrong.
.....well....interesting,.....I like the fact that the "Rockman" is willing to think a little...I'd like to examine the statement from his last post, not to drag him through the mud either.
" I think the DP wouldn't add anything to the effective mud weight. Just like hanging a lead weight in a glass of water: doesn't make the glass any heavier. The weight of the DP is being transferred to the BOP and not the bottom of the hole IMHO. "
.........actually, just for a simple experiment, because I doubt the truth of that statement , I took a digital scale, and a small plastic container filled with water, weighed the total, and displaced some fluid by immersing the end of an X-acto knife.
What I observe.....actually, once the mass is added, it becomes part of the total weight in the fluid.
........so again that leaves me with the question I originally asked.
" How do you remove the drill pipe and replace the missing mass with mud at the same time ? "
.....In my little brain, I see an easy way to remove the drillpipe, simply by pumping the mud down through the top of the pipe so the mud mass will be deposited at the bottom and will replace the mass removed (drillpipe) at exactly the same time.
.......that's if they can actually get the new cap to function correctly....>facepalm<
....that's all for now, I'm off to do some math-n-sh*t.
Sunday, August 22, 2010
Casimir ?
HHmmm...I'm a little confused about this as well, excuse my crude diagrams, I just thought I'd throw this out there for consideration, although ,like much of my speculating, I am only guessing with what I know, which is not too much.
Thursday, August 19, 2010
Sniff testing the pressure test.......
Pressure testing...? Seriously, how can shutting the well in determine where any leaks are ?
Why blur the lines with changing definitions..? .pressure testing, integrity testing, same difference.
One of my main curiosities over the past 3 months was how produced sand would figure into this scenario.
Now we get reports of possible collapses downhole....duh.....didn't see that coming, how could you possibly think that over 3 months, that some sort of subsidence would not happen ?
Bore collapses when drilling original well, bore starts to slough after drilling was halted for storm evacuation...
....brittle shale over sand/sandstone........
...so here we sit, waiting to hear the next news ....I would put money on more delays and pressure testing.
Why blur the lines with changing definitions..? .pressure testing, integrity testing, same difference.
One of my main curiosities over the past 3 months was how produced sand would figure into this scenario.
Now we get reports of possible collapses downhole....duh.....didn't see that coming, how could you possibly think that over 3 months, that some sort of subsidence would not happen ?
Bore collapses when drilling original well, bore starts to slough after drilling was halted for storm evacuation...
....brittle shale over sand/sandstone........
...so here we sit, waiting to hear the next news ....I would put money on more delays and pressure testing.
A virtual rainbow
Many time I have been watching the feeds of the ROV cams, only to see so many different lighting types, but also different colors, I'm sure you have too....
I have my theory about the different colors, I thinks it's basically caused by sonar. I'll explain with a few simple excerpts from Wikipedia.
Raman scattering or the Raman effect
In 1922, Indian physicist C. V. Raman published his work on the "Molecular Diffraction of Light," the first of a series of investigations with his collaborators which ultimately led to his discovery (on 28 February 1928) of the radiation effect which bears his name. The Raman effect was first reported by C. V. Raman and K. S. Krishnan, and independently by Grigory Landsberg and Leonid Mandelstam, in 1928. Raman received the Nobel Prize in 1930 for his work on the scattering of light.
When light is scattered from an atom or molecule, most photons are elastically scattered (Rayleigh scattering), such that the scattered photons have the same energy (frequency) and wavelength as the incident photons. However, a small fraction of the scattered light (approximately 1 in 10 million photons) is scattered by an excitation, with the scattered photons having a frequency different from, and usually lower than, the frequency of the incident photons. In a gas, Raman scattering can occur with a change in vibrational, rotational or electronic energy of a molecule . Chemists are concerned primarily with the vibrational Raman effect.
The Raman effect differs from the process of fluorescence. For the latter, the incident light is completely absorbed and the system is transferred to an excited state from which it can go to various lower states only after a certain resonance lifetime. The result of both processes is essentially the same: A photon with the frequency different from that of the incident photon is produced and the molecule is brought to a higher or lower energy level.
But the major difference is that the Raman effect can take place for any frequency of the incident light.
Here's some various minerals under the effect, beautiful...
http://en.wikipedia.org/wiki/Raman_scattering
So lets say that a certain wavelength of sonar was being used in front of an ROV,. The ROV is using the sonar, and at the same time, lighting the area and filming simultaneously. There are many things suspended in the water around the well, everything from heavy ppms of various minerals, to COREXIT ( there is an autonomous dispersant system in use on the seafloor, it's in the official BP press release documents. ) to dispersed oil, etc etc, I'll skip a long-winded list, I'm sure you get the idea. . So....sonar.....suspended particulates, ultrasonically attenuated light and fluorescing minerals and compounds....seems fairly simple to me.
http://en.wikipedia.org/wiki/Attenuation#Ultrasound
The frequency of light scattered from a molecule may be changed based on the structural characteristics of the molecular bonds. Attenuation of light is important in physical oceanography. Here, attenuation is the decrease in light intensity with depth due to absorption by water molecules and scattering by suspended particulates. This same effect is an important consideration in weather radar as rain drops absorb a part of the emitted beam that is more or less significant depending on the wavelength used.
......ultrasound can also effect transmission in fiber optic lines, which is what ROV's use to send all data to the surface., but I'm sure you read those Wikipedia pages, right ?
I have my theory about the different colors, I thinks it's basically caused by sonar. I'll explain with a few simple excerpts from Wikipedia.
Raman scattering or the Raman effect
In 1922, Indian physicist C. V. Raman published his work on the "Molecular Diffraction of Light," the first of a series of investigations with his collaborators which ultimately led to his discovery (on 28 February 1928) of the radiation effect which bears his name. The Raman effect was first reported by C. V. Raman and K. S. Krishnan, and independently by Grigory Landsberg and Leonid Mandelstam, in 1928. Raman received the Nobel Prize in 1930 for his work on the scattering of light.
When light is scattered from an atom or molecule, most photons are elastically scattered (Rayleigh scattering), such that the scattered photons have the same energy (frequency) and wavelength as the incident photons. However, a small fraction of the scattered light (approximately 1 in 10 million photons) is scattered by an excitation, with the scattered photons having a frequency different from, and usually lower than, the frequency of the incident photons. In a gas, Raman scattering can occur with a change in vibrational, rotational or electronic energy of a molecule . Chemists are concerned primarily with the vibrational Raman effect.
The Raman effect differs from the process of fluorescence. For the latter, the incident light is completely absorbed and the system is transferred to an excited state from which it can go to various lower states only after a certain resonance lifetime. The result of both processes is essentially the same: A photon with the frequency different from that of the incident photon is produced and the molecule is brought to a higher or lower energy level.
But the major difference is that the Raman effect can take place for any frequency of the incident light.
Here's some various minerals under the effect, beautiful...
http://en.wikipedia.org/wiki/Raman_scattering
So lets say that a certain wavelength of sonar was being used in front of an ROV,. The ROV is using the sonar, and at the same time, lighting the area and filming simultaneously. There are many things suspended in the water around the well, everything from heavy ppms of various minerals, to COREXIT ( there is an autonomous dispersant system in use on the seafloor, it's in the official BP press release documents. ) to dispersed oil, etc etc, I'll skip a long-winded list, I'm sure you get the idea. . So....sonar.....suspended particulates, ultrasonically attenuated light and fluorescing minerals and compounds....seems fairly simple to me.
http://en.wikipedia.org/wiki/Attenuation#Ultrasound
The frequency of light scattered from a molecule may be changed based on the structural characteristics of the molecular bonds. Attenuation of light is important in physical oceanography. Here, attenuation is the decrease in light intensity with depth due to absorption by water molecules and scattering by suspended particulates. This same effect is an important consideration in weather radar as rain drops absorb a part of the emitted beam that is more or less significant depending on the wavelength used.
......ultrasound can also effect transmission in fiber optic lines, which is what ROV's use to send all data to the surface., but I'm sure you read those Wikipedia pages, right ?
Removing the BOP stack..?
Hhhmm.........ok.....I'd like to know how this is going to be accomplished.
After Deepwater Horizon sinking, with the riser still attached.....I have my doubts that the shallow cement shoes are sturdy , I have a real hard time believing that there is oil & gas not leaking up the annulus, from the reservoir or higher areas around the wellbore ( They are called" lenticulars " or lenses of sand and are found laterally to the side of the bore in surrounding formations of shale ) and finding un-seated joints in the wellbore and migrating laterally out through the mudline, I have an even harder time believing that there was no damage to the outer layer of cement lining the wellbore when DWH sank.
We all know that they had to use cables and winches to straighten out the flex joint on top of the BOP stack, before they added the 3-ram capping stack.
Why...?
Because it was bent,..... and if it was bent, than that means that the force applied when the sinking platform torqued not just the flex-joint , but the other parts of the system below it, all of which are joined with technical precision in a series of hubs, locks and seals which allow various parts of the system to fit together, and fit together well enough to contain high volume flows of crude oil and gas.
Looking at the following diagram, I still have my doubts these connections are 100% structurally integral.
....here is a rare picture....the base of the BOP at the ocean floor...look undamaged to you...?
............ So how do you remove the BOP stack and attach a new one to a damaged connection ?
.......then there's that ugly fact they cemented (read "trapped" ) fluid into a supposedly sealed space, ie" the annulus ", so there's a fluid of unknown compressability in a space whose integrity is unknown also....great.
.....for weeks now, I have wondered where this trapped fluid was supposed to go...?
. ....if the cement at the bottom was completely blocking flow ( communication ) with the reservoir and thereby blocking any fluids from coming up the annulus, why are they looking for seeps ?
...and... BTW, try to find any info on high volume/large biogenic seeps like Ken Wells says was the source of the gas around the wellhead....you won't find biogenic methane being produced in large enough quantities to vent from the seafloor,....it gets frozen into hydrates long before it leaks out of the mud and rock.
..Then it can get warmed and will dissociate in large enough amounts to be noticeable as a seep, if fluids erode their way into the area they have formed in.
......if what Mr.Wells were saying was true, those particular " miracle " microbes would be put to use already in the petroleum industry making natural gas....
....Only thermogenic gas can migrate fast enough to establish pathways in the strata, only thermogenic is produced in those high quantities. Yes, there are biological traces of microbial gas ( methogenic, biogenic ) in most thermogenic gas, but are they are a small fraction considering the main source they are found with.
...if the wellbore isn't damaged, the annulus shouldn't be leaking into the surrounding geology and finding it's way up though the mud.
...if it is damaged....how do you guarantee that any fluids/cement you pump into it won't just get pushed right up and out... ?
......if the cement job is allowing fluids to leak up the annulus from the reservoir, then how will it provide enough resistance for the incoming mud to push the heavier fluid up through the annulus, instead of blowing the plug out backwards into the reservoir ?
......at least this sudden conundrum should quell myths about " switched-out wellheads" and blowout preventers secretly already replaced in secretive underwater operations.
......But,... enough with off-the-cuff engineering, seriously,.. what's next ...?..the flux capacitor and the inverted-vortex 9 ram gate-valve-piston shear capping-riser ?
....Can I get a shake & some fries with that ?
..
After Deepwater Horizon sinking, with the riser still attached.....I have my doubts that the shallow cement shoes are sturdy , I have a real hard time believing that there is oil & gas not leaking up the annulus, from the reservoir or higher areas around the wellbore ( They are called" lenticulars " or lenses of sand and are found laterally to the side of the bore in surrounding formations of shale ) and finding un-seated joints in the wellbore and migrating laterally out through the mudline, I have an even harder time believing that there was no damage to the outer layer of cement lining the wellbore when DWH sank.
We all know that they had to use cables and winches to straighten out the flex joint on top of the BOP stack, before they added the 3-ram capping stack.
Why...?
Because it was bent,..... and if it was bent, than that means that the force applied when the sinking platform torqued not just the flex-joint , but the other parts of the system below it, all of which are joined with technical precision in a series of hubs, locks and seals which allow various parts of the system to fit together, and fit together well enough to contain high volume flows of crude oil and gas.
Looking at the following diagram, I still have my doubts these connections are 100% structurally integral.
....here is a rare picture....the base of the BOP at the ocean floor...look undamaged to you...?
............ So how do you remove the BOP stack and attach a new one to a damaged connection ?
.......then there's that ugly fact they cemented (read "trapped" ) fluid into a supposedly sealed space, ie" the annulus ", so there's a fluid of unknown compressability in a space whose integrity is unknown also....great.
.....for weeks now, I have wondered where this trapped fluid was supposed to go...?
. ....if the cement at the bottom was completely blocking flow ( communication ) with the reservoir and thereby blocking any fluids from coming up the annulus, why are they looking for seeps ?
...and... BTW, try to find any info on high volume/large biogenic seeps like Ken Wells says was the source of the gas around the wellhead....you won't find biogenic methane being produced in large enough quantities to vent from the seafloor,....it gets frozen into hydrates long before it leaks out of the mud and rock.
..Then it can get warmed and will dissociate in large enough amounts to be noticeable as a seep, if fluids erode their way into the area they have formed in.
......if what Mr.Wells were saying was true, those particular " miracle " microbes would be put to use already in the petroleum industry making natural gas....
....Only thermogenic gas can migrate fast enough to establish pathways in the strata, only thermogenic is produced in those high quantities. Yes, there are biological traces of microbial gas ( methogenic, biogenic ) in most thermogenic gas, but are they are a small fraction considering the main source they are found with.
...if the wellbore isn't damaged, the annulus shouldn't be leaking into the surrounding geology and finding it's way up though the mud.
...if it is damaged....how do you guarantee that any fluids/cement you pump into it won't just get pushed right up and out... ?
......if the cement job is allowing fluids to leak up the annulus from the reservoir, then how will it provide enough resistance for the incoming mud to push the heavier fluid up through the annulus, instead of blowing the plug out backwards into the reservoir ?
......at least this sudden conundrum should quell myths about " switched-out wellheads" and blowout preventers secretly already replaced in secretive underwater operations.
......But,... enough with off-the-cuff engineering, seriously,.. what's next ...?..the flux capacitor and the inverted-vortex 9 ram gate-valve-piston shear capping-riser ?
....Can I get a shake & some fries with that ?
..
Wednesday, August 18, 2010
Sniff testing...?
I can tell you that from my training as a chef, that sniff testing is complete and utter bullshit.
Any chef or cook knows that seafood, especially processed seafood, can smell...questionable.....at any given time. Unfortunately the majority of seafood sold to restaurants has been treated, frozen, sometimes thawed and frozen by accident several times.
As a few examples:
Ahi Tuna steaks served by most restaurants....nice and pink..
.....It's gassed on the boat at sea with carbon monoxide to keep the flesh from oxidizing and turning brown, then flash-frozen. Yum.
Scallops, nice and juicy tender ...
....wet-packed with tri-sodium phosphate for moisture retention ( read=adding weight to the product in the form of water )
Black Tiger shrimps from Thailand, sweet and meaty
...Thai fishermen are fond of pouring a little bit of diesel fuel into their catch holds to prevent seafood from rotting when there is no refrigeration available on the vessel, common.
........So the truth of the matter is that if you are used to cooking with things that already have a "funny smell", then sniff testing is pointless.
Now, let's ask some crucial questions :
Has the testing taken into account that there are various types of fish ?
Has the testing examined the various parts of the fish ?
How has testing declared seafood safe to eat, when there are no previous studies to go by ?
Why is only "sniff-testing" being suggested ?
Has NALCO been asked for the proprietary information about COREXIT's constituents ?
Fatty fish don't get around too much, lean fish are travelers. It's like the difference between farm-raised salmon and wild-caught salmon. Farm raised salmon are much fattier, they don't have too many chances to get exercise, hence the fat.
There has been no testing of various parts of the fish....when I get a whole fish, I break it down, and usually make a nice fumet out of the body and head ( stock )...although not always the heads, depends on the fish I am using.
Large processing operations and small processors alike, sell their scraps. If you are on the coast, most likely, you can get fish bodies for stock from your local purveyor.
Larger plants will sell their scraps for pet food, fertilizer, and ........cooking into commercial soup bases, which many restaurant sadly use these days to make soups, stews and sauces.
Pollutants tend to bio-accumulate in different areas of an organism, fatty tissues are a favorite location, but organs like the liver are prime targets too.
Until I see some shrimp, scallops, and whole fish, split head to tail and examined under UV light for presence of hydrocarbons, I will be suspicious. ...and I'm sure, given modern technology, that we can come up with a better testing method....
..... like I tell people, " if you don't mind, than it doesn't matter ".
Any chef or cook knows that seafood, especially processed seafood, can smell...questionable.....at any given time. Unfortunately the majority of seafood sold to restaurants has been treated, frozen, sometimes thawed and frozen by accident several times.
As a few examples:
Ahi Tuna steaks served by most restaurants....nice and pink..
.....It's gassed on the boat at sea with carbon monoxide to keep the flesh from oxidizing and turning brown, then flash-frozen. Yum.
Scallops, nice and juicy tender ...
....wet-packed with tri-sodium phosphate for moisture retention ( read=adding weight to the product in the form of water )
Black Tiger shrimps from Thailand, sweet and meaty
...Thai fishermen are fond of pouring a little bit of diesel fuel into their catch holds to prevent seafood from rotting when there is no refrigeration available on the vessel, common.
........So the truth of the matter is that if you are used to cooking with things that already have a "funny smell", then sniff testing is pointless.
Now, let's ask some crucial questions :
Has the testing taken into account that there are various types of fish ?
Has the testing examined the various parts of the fish ?
How has testing declared seafood safe to eat, when there are no previous studies to go by ?
Why is only "sniff-testing" being suggested ?
Has NALCO been asked for the proprietary information about COREXIT's constituents ?
Fatty fish don't get around too much, lean fish are travelers. It's like the difference between farm-raised salmon and wild-caught salmon. Farm raised salmon are much fattier, they don't have too many chances to get exercise, hence the fat.
There has been no testing of various parts of the fish....when I get a whole fish, I break it down, and usually make a nice fumet out of the body and head ( stock )...although not always the heads, depends on the fish I am using.
Large processing operations and small processors alike, sell their scraps. If you are on the coast, most likely, you can get fish bodies for stock from your local purveyor.
Larger plants will sell their scraps for pet food, fertilizer, and ........cooking into commercial soup bases, which many restaurant sadly use these days to make soups, stews and sauces.
Pollutants tend to bio-accumulate in different areas of an organism, fatty tissues are a favorite location, but organs like the liver are prime targets too.
Until I see some shrimp, scallops, and whole fish, split head to tail and examined under UV light for presence of hydrocarbons, I will be suspicious. ...and I'm sure, given modern technology, that we can come up with a better testing method....
..... like I tell people, " if you don't mind, than it doesn't matter ".
New system in development..seems familiar in concept to something...oh yeah, I remember..
........My idea for containing the wellhead.
...Although different in design, exactly the same in concept.....large heavy box with the ability to capture oil.
You can bet I will keep track of this "new" developing technology, just out of curiosity of course.
The following is from the Oil Drum
" If the integrity of the end of the well is compromised (i.e. the rock fragmented, the liners broken or the wellhead destroyed in some way), then a different approach will be required.
Here a caisson assembly will be constructed around the remnant BOP, large enough to surround the well at a point where the rock has enough strength and quality to allow a seal under the wall. This will then allow a cap to be placed on top of the caisson, with the containment system from the last slide, mounted on top of the cap, as a way of capturing the hydrocarbons that are bled off from the well, without their coming into contact with the seawater, and forming hydrates. "
(ExxonMobil )
----------------------------------------------------------------------------
Lol, Isaac wants royalties....or some help getting student loans to study engineering...hint hint
...Although different in design, exactly the same in concept.....large heavy box with the ability to capture oil.
You can bet I will keep track of this "new" developing technology, just out of curiosity of course.
The following is from the Oil Drum
" If the integrity of the end of the well is compromised (i.e. the rock fragmented, the liners broken or the wellhead destroyed in some way), then a different approach will be required.
Here a caisson assembly will be constructed around the remnant BOP, large enough to surround the well at a point where the rock has enough strength and quality to allow a seal under the wall. This will then allow a cap to be placed on top of the caisson, with the containment system from the last slide, mounted on top of the cap, as a way of capturing the hydrocarbons that are bled off from the well, without their coming into contact with the seawater, and forming hydrates. "
----------------------------------------------------------------------------
Lol, Isaac wants royalties....or some help getting student loans to study engineering...hint hint
Tuesday, August 17, 2010
Oil starting to seep
Not good. Just flat-out not good. If there were any leaks coming up through the mudline, gas would have been first, followed later by oil, which appears to happening more often now.
.. Time's a' wastin'
.. Time's a' wastin'
Sunday, August 15, 2010
A different perspective
I really think you will enjoy these videos a friend suggested. It's about some things from a different perspective, from a brilliant man , Volker Pispers
1
2
3
4
5
1
2
3
4
5
Hydrates : Dissociation or dissolution...?
Hydrates have been on the table for discussion for quite some time, there have been many conjectures about methane, venting of the seafloor, giant methane bubbles, etc, etc. I would like to take a stab at describing some possibilities that might explain some of the things we have all been seeing on the ROV feeds.
Especially the " white things " everyone sees " swimming " around on the live feeds and can't decide whether they are hydrate chunks, gas bubbles ,crustaceans , marine snow, silt, floating bacterial mats, oil ,...or alien fire bugs,lol.
I'll give you a hint....
It's 7 out of 8 things I just mentioned.
And most interesting,...free floating hydrate chunks exhibit what is called " wiggling "
There is a big difference between the acts of dissolution and dissociation in hydrates.
" Dissociation is due to inherent instability (similar to melting of ice) with or without water (although presence of warm water may increase the dissociation rate). Dissociation of methane hydrate into gas and water is similar to ice melting and is controlled by heat transfer. Hence dissolution is relatively slow and dissociation is rapid. "
" Dissolution is due to instability in the presence of seawater (similar to dissolution of NaCl in water) and is controlled by mass transfer. "
Hydrates form where they can and when they can. If rock or mud is already saturated than hydrates will not form, the gas will vent upwards through the seafloor because it has to, although there are such things as gas traps, they are not know to be the size of Rhode Island..it would be almost physically impossible unless there were a massive upturned cup structure ( a fold ) in the bedrock consisting of very non-porous rock, and it would have to be massive, and it would have had to have had a massive "washout " to excavate the cavity for the gas to collect in , in the first place....highly unlikely.
Originally, I had become curious about hydrates and the characteristics of the gas I was seeing on the live feeds.
In particular, I noticed bubbles of gas that were leaking from a certain pressure-fit connection between the original BOP stack and the additional " 3-ram capping stack ". The feeds were showing the buildup of hydrates on the structure, but was most puzzling to me was the way the bubbles were rising up hitting the hydrates....and then careening straight off at a 90 degree angle....this didn't make much sense to me....you would think that a bubble would rise up, hit the hydrates, bounce off and continue upward, right ?
You would expect to see it go from a vertical trajectory to the bounce and a gradual arc as it resumed a vertical trajectory. I made the above crude diagram to demonstrate what I am talking about, where A: would be what I would expect to see, and B: what I did see. I really wish I could have gotten video captures, it was when the feeds were of higher quality.....I searched for some vids to show what I saw, but I have not found any.
Odd behavior for a bubble,I thought , so I asked a friend, this is what he said.
"Presumably the hydrate formers pickup water quickly and become more hydrophilic, they would bounce off of presumed hydrophobic oil. It may be worth looking at the surfaces of some of these things and see how they can segregate under various forces. Hydrophilic/phobic drives many things- for example protein folding that makes enzymes works can be driven by this. Pressure gradients through various size pores of course select on size, and I wouldn't ignore electrochemical issues too. A field will orient polar molecules, induce dipoles and get net-neutrals to migrate. Electrophoretic separation if you will. Interesting, but a couple of lidar hits on the different blobs would be a lot more informative. "
..lol...so basically this is a small but violent transfer of mass that sends the bubble on a horizontal trajectory.
The warmer gas escapes from a higher pressure to a lower pressure, rises up, hits the much colder hydrates where it instantly becomes much lower in temperature, in turn lowering the temperature of the water it contacts, resulting in the rapid growth of the typical crystalline structure of a hydrate ( there are 7 I believe ) and trapping a small amount of gas When the temperature differentials of the gas bubble and the hydrate and the ambient temperature converge, the reaction can longer take place, but is also halted in a very fast and (micro) violent way,ie: a sudden stop, which provides the opposite force to send the bubble careening off.
( The following is quoted from a linked paper below )
" If the bonds in the crystal are weak and hence easy to break, then interface reaction rate would be high, and dissolution would be controlled by mass transfer. If the bonds are strong and hence difficult to break, then interface reaction rate would be low and dissolution would be controlled by the interface reaction rate. "
Then there is Snell's law, which I may be applying incorrectly to prove a point, although I have read it can also be used to describe what I am talking about, ipse dixit.
Wavefronts from a point source in the context of Snell's law.
...so that's my attempt to explain that , it is slightly ipse dixit .
..... Let's look at some things.
First , a video a good friend sent me of a venting of gas from the seafloor.
The only things that makes me question the origin of the gas in that video above are: the characteristics of what I observed in that release, compared to all of the other videos on natural methane seeps, those of which are from footage pre-Horizon. Normal natural releases of methane are released as bubbles in a fairly steady stream.
I specifically remember before they put on the " 3 ram capping-stack, that they expected to see some gas venting in the surrounding area. I also remember Ken Wells saying this gas was from a biogenic source. That video is not biogenic gas production. That is a rather large bubble of gas rising up through the mudline, breaking the surface, and being forced into a vortice by ambient pressure. I observed the same event several times when the cap was initially applied.
When the cap was installed, I saw several of these gas vortices, sans sediment, that lasted for around 45 seconds each, from the POV( point of view ) which was at least 10' off the seafloor, probably more like 20+', they were inches from the camera . The ROV operator noticed them too, he panned the camera to look at it. An undulating silver snake dancing in the depths, it was beautiful really, and I was too stunned to capture the vid...dang.
If these vortices were propwash, they would not be monitoring them , let alone from the same spot. I don't think a vortice created from an ROV thruster could generate enough power to suck gases out of the mudline against ambient water pressure,jmnsho. Gas vents from the seafloor either when the mud and rock cannot absorb anymore gas, or there is a clear/semi-clear path that has already been established, ie: a vent or chimney.
I do believe that it's possible different gases would travel differently due to their characteristics, some gas would be less prone to creep through rock pores, some would be more prone.
.......The hydrate stability zone only extends to around 1000' down.
.......Hydrates normally form in the mudline/stability zone because of contact with liquid (seawater)and temperature/pressure ( P/T )but also dependent on inhibitors to formation like salt and methanol.
....So back to the difference between dissolution and dissociation.
One is happening because hydrates are subjected to heat outside the gradients to keep them stable. Here is a video of hydrates being dissociated from heat, the gas comes up providing lift to the fluids by way of what's known as " gas lift ", basically, the gas expands as it rises, almost dragging the fluids with it, although it is not the prime mover. But observe how the CO2 behaves when clinging to this ROV....
Next is a vid of somebody parking an ROV on a bed of methane hydrates on the seafloor.
** Note : When the video text commentary says that sediment can get stuck to the Plexiglas bubble and the camera will auto focus on it....this could explain many many " sightings " of weird things people have seen.....something I suspected, but it's comical really if you think about it. It's like getting scared while looking through a telescope when a fly lands on the outer lens...lollol.
Also note around 2:20 in the video , the exposed chunks of hydrate. Notice how it's not doing anything basically because its nice and cold., but also because on a molecular level, the rate of slow release of methane from hydrates is partially dictated by the amount of methane already found in the surrounding water saturated by slow rates of dissolution.
...so what i really find curious is tha fact that hydrate chunks we see on the live feeds are appearing to wiggle and swim...this means they are not decaying by dissolution, but by dissociation, which provides thrust force in the form of lost mass. I am wondering if this is from preventative methanol applications remaining in the surrounding are( seawater) or from....raising of the ambient temperature of the seawater , because it would only take a raise of a few degrees to produce rapid dissociation.
Originally for me , the confusion was because the terms of biogenic, methogenic, & chemosynthetic have been used rather loosely in a fair amount of the literature I have come across.( That's about 8-10 hours a day , 7 days a week reading and studying many of these topics ) Than there was petrogenic and thermogenic gas as well. Phew..
" Preliminary Evaluation of In-Place Gas Hydrate Resources: Gulf of Mexico Outer Continental Shelf "
" The rationale is that, if there is sufficient methane flux to vent methane to the seafloor surface (in gas and/or solid phases), the available pore volume must be fully saturated, and, if biogenic gas is not available to completely saturate the section, thermogenic gas is available to do so. "
" Kinetics of convective crystal dissolution and melting, with applications to methane hydrate dissolution and dissociation in seawater "
" Large quantities of methane hydrate are present in marine sediment. When methane hydrate is exposed or released to seawater, it dissolves in seawater or dissociates into methane gas and water. There was some confusion in the literature about the kinetics of these processes. It is critical to realize that dissolution and dissociation are two different processes. Dissolution is due to instability in the presence of seawater (similar to dissolution of NaCl in water) and is controlled by mass transfer. Dissociation is due to inherent instability (similar to melting of ice) with or without water (although presence of warm water may increase the dissociation rate). Dissociation of methane hydrate into gas and water is similar to ice melting and is controlled by heat transfer.
Hence dissolution is relatively slow and dissociation is rapid. "
Now, when I originally posted what my friend had told me, in terms of what was possibly causing the bubbles I was seeing to travel vertically, somebody at the Oil drum ( great site Btw ) asked me this .
" Isaac - perhaps you could venture into this new topic of magnetics and how such a factor would influence the stability of the formations with forced introduction of reactive polar opposites. Very, very interesting - even if only in a speculative manner. Thanx. "
http://www.theoildrum.com/node/6849#comments_top
I remembered a paper I read....
Perhaps you already read it in my " capture and tame " proposal I sent to BP, I'm sure they got a laugh.
From the Japanese Journal of Applied Physics
...hhhmmmm...'thinks'...
Het is tijd om enkele beste knoeiboel te roken die ik ooit heb gezien.
Es ist Zeit, etwas von dem besten Durcheinander zu rauchen, das ich überhaupt gesehen habe.
Lol....so that got me starting thinking about sonar, because they are using sonar to image the seafloor,.... and doing it constantly.
そして心からの感謝への Hikaru Miura、Makoto Takata、Daisuke但馬およびKenichirou Tsuyuki
あなたの研究をするために私がたばこを吸われた挽肉料理疑うが。
Sonar operation is affected by variations in sound speed, particularly in the vertical plane. Sound travels more slowly in fresh water than in sea water, though the difference is small. The speed is determined by the water's bulk modulus and mass density. The bulk modulus is affected by temperature, dissolved impurities (usually salinity), and pressure. The density effect is small. The speed of sound (in feet per second) is approximately:
Different types of active sonars operate at different frequencies, according to their purpose.
High Frequency: High frequency sonar (>10 kHz) is primarily used for determining water depth (fathometers), hunting mines, and guiding torpedoes. At higher frequencies, the sound energy is greatly attenuated (weakened due to scattering and absorption) as it travels through the water. This results in shorter ranges, typically less than five nautical miles.
Mid Frequency: Mid frequency sonar, which includes the AN/SQS-53 system, has been in use since World War II, and is the primary tool for identifying and prosecuting submarines. Mid frequency sonar (1 kHz - 10 kHz) suffers moderate attenuation and has typical ranges of 1-10 nautical miles.
Low Frequency: Low frequency sonar (< 1 kHz) produces sound that suffers less attenuation as it travels through the water, providing greater range than other sonars. Achieving ranges up to 100 nautical miles, low frequency sonars are primarily used for long-range search and surveillance of submarines. Surveillance Towed Array Sensor System Low Frequency Active (SURTASS LFA) is the U.S. Navy's low-frequency sonar system.
Sonar works as follows:
....so's I ask myself/s,...what kind of equipment would they be using to look for hydrates....and would they be looking for hydrates, ...which they wouldn't if the surrounding seafloor/mudline was slowly heating up, if it were, the methane released would be diffused in bubble form so small you wouldn't see them anyway.....you only see large bubbles when methane is either from a thermogenic release ...ie...with heat.
so anyway...Ultrasound attenuation spectroscopy is what is used. Here's a handy project from the D.O.E.
" Characterization of Natural Hydrate Bearing Sediments and Hydrate Dissociation Kinetics "
" The successive shock wave pressure pulses result in direct shearing forces, as well as cavitation bubbles surrounding the stone "
So then with ultrasonic sonar and suspended gas being present there is what's known as " inertial cavitation "
" Inertial cavitation can also occur in the presence of an acoustic field. Microscopic gas bubbles that are generally present in a liquid will be forced to oscillate due to an applied acoustic field. If the acoustic intensity is sufficiently high, the bubbles will first grow in size and then rapidly collapse.
Controlled cavitation can be used to enhance chemical reactions or propagate certain unexpected reactions because free radicals are generated in the process due to disassociation of vapors trapped in the cavitating bubbles. "
http://en.wikipedia.org/wiki/Cavitation
...so in conclusion to this particularly flatulent post,: :
I think that many of the things we see on the ROV cams can easily be explained with modern scientific knowledge. Hydrate chunks will " swim " as they lose gas, etc.
But one thing I know after all this conjecture for sure....and that's that normal established gas and oil seeps always have other established marine life where they are found.
Always.
If you have any questions just leave a comment if you can't get ahold of me in the chatbox
Thanks for reading my blog, Isaac
Especially the " white things " everyone sees " swimming " around on the live feeds and can't decide whether they are hydrate chunks, gas bubbles ,crustaceans , marine snow, silt, floating bacterial mats, oil ,...or alien fire bugs,lol.
I'll give you a hint....
It's 7 out of 8 things I just mentioned.
And most interesting,...free floating hydrate chunks exhibit what is called " wiggling "
There is a big difference between the acts of dissolution and dissociation in hydrates.
" Dissociation is due to inherent instability (similar to melting of ice) with or without water (although presence of warm water may increase the dissociation rate). Dissociation of methane hydrate into gas and water is similar to ice melting and is controlled by heat transfer. Hence dissolution is relatively slow and dissociation is rapid. "
" Dissolution is due to instability in the presence of seawater (similar to dissolution of NaCl in water) and is controlled by mass transfer. "
Hydrates form where they can and when they can. If rock or mud is already saturated than hydrates will not form, the gas will vent upwards through the seafloor because it has to, although there are such things as gas traps, they are not know to be the size of Rhode Island..it would be almost physically impossible unless there were a massive upturned cup structure ( a fold ) in the bedrock consisting of very non-porous rock, and it would have to be massive, and it would have had to have had a massive "washout " to excavate the cavity for the gas to collect in , in the first place....highly unlikely.
Originally, I had become curious about hydrates and the characteristics of the gas I was seeing on the live feeds.
In particular, I noticed bubbles of gas that were leaking from a certain pressure-fit connection between the original BOP stack and the additional " 3-ram capping stack ". The feeds were showing the buildup of hydrates on the structure, but was most puzzling to me was the way the bubbles were rising up hitting the hydrates....and then careening straight off at a 90 degree angle....this didn't make much sense to me....you would think that a bubble would rise up, hit the hydrates, bounce off and continue upward, right ?
You would expect to see it go from a vertical trajectory to the bounce and a gradual arc as it resumed a vertical trajectory. I made the above crude diagram to demonstrate what I am talking about, where A: would be what I would expect to see, and B: what I did see. I really wish I could have gotten video captures, it was when the feeds were of higher quality.....I searched for some vids to show what I saw, but I have not found any.
Odd behavior for a bubble,I thought , so I asked a friend, this is what he said.
"Presumably the hydrate formers pickup water quickly and become more hydrophilic, they would bounce off of presumed hydrophobic oil. It may be worth looking at the surfaces of some of these things and see how they can segregate under various forces. Hydrophilic/phobic drives many things- for example protein folding that makes enzymes works can be driven by this. Pressure gradients through various size pores of course select on size, and I wouldn't ignore electrochemical issues too. A field will orient polar molecules, induce dipoles and get net-neutrals to migrate. Electrophoretic separation if you will. Interesting, but a couple of lidar hits on the different blobs would be a lot more informative. "
..lol...so basically this is a small but violent transfer of mass that sends the bubble on a horizontal trajectory.
The warmer gas escapes from a higher pressure to a lower pressure, rises up, hits the much colder hydrates where it instantly becomes much lower in temperature, in turn lowering the temperature of the water it contacts, resulting in the rapid growth of the typical crystalline structure of a hydrate ( there are 7 I believe ) and trapping a small amount of gas When the temperature differentials of the gas bubble and the hydrate and the ambient temperature converge, the reaction can longer take place, but is also halted in a very fast and (micro) violent way,ie: a sudden stop, which provides the opposite force to send the bubble careening off.
( The following is quoted from a linked paper below )
" If the bonds in the crystal are weak and hence easy to break, then interface reaction rate would be high, and dissolution would be controlled by mass transfer. If the bonds are strong and hence difficult to break, then interface reaction rate would be low and dissolution would be controlled by the interface reaction rate. "
Then there is Snell's law, which I may be applying incorrectly to prove a point, although I have read it can also be used to describe what I am talking about, ipse dixit.
Wavefronts from a point source in the context of Snell's law.
...so that's my attempt to explain that , it is slightly ipse dixit .
..... Let's look at some things.
First , a video a good friend sent me of a venting of gas from the seafloor.
The only things that makes me question the origin of the gas in that video above are: the characteristics of what I observed in that release, compared to all of the other videos on natural methane seeps, those of which are from footage pre-Horizon. Normal natural releases of methane are released as bubbles in a fairly steady stream.
I specifically remember before they put on the " 3 ram capping-stack, that they expected to see some gas venting in the surrounding area. I also remember Ken Wells saying this gas was from a biogenic source. That video is not biogenic gas production. That is a rather large bubble of gas rising up through the mudline, breaking the surface, and being forced into a vortice by ambient pressure. I observed the same event several times when the cap was initially applied.
When the cap was installed, I saw several of these gas vortices, sans sediment, that lasted for around 45 seconds each, from the POV( point of view ) which was at least 10' off the seafloor, probably more like 20+', they were inches from the camera . The ROV operator noticed them too, he panned the camera to look at it. An undulating silver snake dancing in the depths, it was beautiful really, and I was too stunned to capture the vid...dang.
If these vortices were propwash, they would not be monitoring them , let alone from the same spot. I don't think a vortice created from an ROV thruster could generate enough power to suck gases out of the mudline against ambient water pressure,jmnsho. Gas vents from the seafloor either when the mud and rock cannot absorb anymore gas, or there is a clear/semi-clear path that has already been established, ie: a vent or chimney.
I do believe that it's possible different gases would travel differently due to their characteristics, some gas would be less prone to creep through rock pores, some would be more prone.
.......The hydrate stability zone only extends to around 1000' down.
.......Hydrates normally form in the mudline/stability zone because of contact with liquid (seawater)and temperature/pressure ( P/T )but also dependent on inhibitors to formation like salt and methanol.
....So back to the difference between dissolution and dissociation.
One is happening because hydrates are subjected to heat outside the gradients to keep them stable. Here is a video of hydrates being dissociated from heat, the gas comes up providing lift to the fluids by way of what's known as " gas lift ", basically, the gas expands as it rises, almost dragging the fluids with it, although it is not the prime mover. But observe how the CO2 behaves when clinging to this ROV....
Next is a vid of somebody parking an ROV on a bed of methane hydrates on the seafloor.
** Note : When the video text commentary says that sediment can get stuck to the Plexiglas bubble and the camera will auto focus on it....this could explain many many " sightings " of weird things people have seen.....something I suspected, but it's comical really if you think about it. It's like getting scared while looking through a telescope when a fly lands on the outer lens...lollol.
Also note around 2:20 in the video , the exposed chunks of hydrate. Notice how it's not doing anything basically because its nice and cold., but also because on a molecular level, the rate of slow release of methane from hydrates is partially dictated by the amount of methane already found in the surrounding water saturated by slow rates of dissolution.
...so what i really find curious is tha fact that hydrate chunks we see on the live feeds are appearing to wiggle and swim...this means they are not decaying by dissolution, but by dissociation, which provides thrust force in the form of lost mass. I am wondering if this is from preventative methanol applications remaining in the surrounding are( seawater) or from....raising of the ambient temperature of the seawater , because it would only take a raise of a few degrees to produce rapid dissociation.
Originally for me , the confusion was because the terms of biogenic, methogenic, & chemosynthetic have been used rather loosely in a fair amount of the literature I have come across.( That's about 8-10 hours a day , 7 days a week reading and studying many of these topics ) Than there was petrogenic and thermogenic gas as well. Phew..
" Preliminary Evaluation of In-Place Gas Hydrate Resources: Gulf of Mexico Outer Continental Shelf "
" The rationale is that, if there is sufficient methane flux to vent methane to the seafloor surface (in gas and/or solid phases), the available pore volume must be fully saturated, and, if biogenic gas is not available to completely saturate the section, thermogenic gas is available to do so. "
" Hydrocarbon Systems Analysis of the Northern Gulf of Mexico: Delineation of Hydrocarbon Migration Pathways Using Seeps and Seismic Imaging. "
....so after all that reading, here's some more.
" Large quantities of methane hydrate are present in marine sediment. When methane hydrate is exposed or released to seawater, it dissolves in seawater or dissociates into methane gas and water. There was some confusion in the literature about the kinetics of these processes. It is critical to realize that dissolution and dissociation are two different processes. Dissolution is due to instability in the presence of seawater (similar to dissolution of NaCl in water) and is controlled by mass transfer. Dissociation is due to inherent instability (similar to melting of ice) with or without water (although presence of warm water may increase the dissociation rate). Dissociation of methane hydrate into gas and water is similar to ice melting and is controlled by heat transfer.
Hence dissolution is relatively slow and dissociation is rapid. "
Now, when I originally posted what my friend had told me, in terms of what was possibly causing the bubbles I was seeing to travel vertically, somebody at the Oil drum ( great site Btw ) asked me this .
" Isaac - perhaps you could venture into this new topic of magnetics and how such a factor would influence the stability of the formations with forced introduction of reactive polar opposites. Very, very interesting - even if only in a speculative manner. Thanx. "
http://www.theoildrum.com/node/6849#comments_top
I remembered a paper I read....
Perhaps you already read it in my " capture and tame " proposal I sent to BP, I'm sure they got a laugh.
From the Japanese Journal of Applied Physics
" Promotion of Methane Hydrate Dissociation by Underwater Ultrasonic Wave "
" The methane hydrate that exists in the abyssal floor is receiving attention as a nonconventional type of natural gas resource. An efficient dissociation technology is necessary and indispensable to achieve a steady supply of methane from methane hydrate because it does not easily dissociate in a stable environment of high pressure and low temperature. We consider that underwater ultrasonic wave irradiation may be a method of promoting the dissociation of methane hydrate on the basis of the facilitator effect. We carried out a preliminary examination using dry ice at various pressures, water temperatures, and input electric power. Methane hydrate was similarly examined. As a result, it was clarified that the dissociation time was shorted by the ultrasonic wave, and the wave was effective when the water temperature was low at the time of dissociation. "...hhhmmmm...'thinks'...
Het is tijd om enkele beste knoeiboel te roken die ik ooit heb gezien.
Es ist Zeit, etwas von dem besten Durcheinander zu rauchen, das ich überhaupt gesehen habe.
Lol....so that got me starting thinking about sonar, because they are using sonar to image the seafloor,.... and doing it constantly.
そして心からの感謝への Hikaru Miura、Makoto Takata、Daisuke但馬およびKenichirou Tsuyuki
あなたの研究をするために私がたばこを吸われた挽肉料理疑うが。
Sonar operation is affected by variations in sound speed, particularly in the vertical plane. Sound travels more slowly in fresh water than in sea water, though the difference is small. The speed is determined by the water's bulk modulus and mass density. The bulk modulus is affected by temperature, dissolved impurities (usually salinity), and pressure. The density effect is small. The speed of sound (in feet per second) is approximately:
- 4388 + (11.25 × temperature (in °F)) + (0.0182 × depth (in feet)) + salinity (in parts-per-thousand ).
- ...ok...I'll take a stab at that for fun....sadly I took a test the other day and my math abilities are around 7th grade according to modern educational standards....lol...but then I read this from a writeup by the physicist Richard Feynman of his experiences on a school textbook review board.
- http://www.textbookleague.org/103feyn.htm
- 4388 +
- (11.25*3ºC) = 33.75
- (0.0182*5k') = 0.03014284
- (salinity in ppt) = 34.9 ( average at that depth )
- = 4456.08014284...that's feet-per-second, or the speed that sound would travel at this depth, pressure and salinity.
Types of Active Sonar
High Frequency: High frequency sonar (>10 kHz) is primarily used for determining water depth (fathometers), hunting mines, and guiding torpedoes. At higher frequencies, the sound energy is greatly attenuated (weakened due to scattering and absorption) as it travels through the water. This results in shorter ranges, typically less than five nautical miles.
Mid Frequency: Mid frequency sonar, which includes the AN/SQS-53 system, has been in use since World War II, and is the primary tool for identifying and prosecuting submarines. Mid frequency sonar (1 kHz - 10 kHz) suffers moderate attenuation and has typical ranges of 1-10 nautical miles.
Low Frequency: Low frequency sonar (< 1 kHz) produces sound that suffers less attenuation as it travels through the water, providing greater range than other sonars. Achieving ranges up to 100 nautical miles, low frequency sonars are primarily used for long-range search and surveillance of submarines. Surveillance Towed Array Sensor System Low Frequency Active (SURTASS LFA) is the U.S. Navy's low-frequency sonar system.
http://www.solcomhouse.com/SONAR.htm
....so I am going to assume, safely, that for close-range sonar operations, they are using active sonar, high-frequency to look for gas seeps after shutting in the well., it would pointless to use anything else, although infrared has been in the back of my mind for quite some time now, because it would work quite well to look for seeps of any kind......unless the ambient temperature of the seawater has been raised....then the higher temp fluids would not show up as easily, granted they would not be very hot at all, they would loose most of their heat migrating up though the mud and surrounding seafloor, unless they were being propelled at a great velocity and high volume, which would indicate a rather large leak, I think we can rule that out, it would be visible from space.
...>10khz ....
- A machine sends out sound waves ("ultrasound," or ultrasonic sound)
- The sound bounces off the seafloor; the reflected sound waves are detected by the machine
- The distance between the machine and the reflecting surface can be calculated from the time the sound takes to travel to the seafloor and back
- By making measurements in different places, the contours of the seafloor can be plotted. As a general rule, the closer you can get the instrument to the seafloor, the greater the resolution of the contour map.
....so's I ask myself/s,...what kind of equipment would they be using to look for hydrates....and would they be looking for hydrates, ...which they wouldn't if the surrounding seafloor/mudline was slowly heating up, if it were, the methane released would be diffused in bubble form so small you wouldn't see them anyway.....you only see large bubbles when methane is either from a thermogenic release ...ie...with heat.
so anyway...Ultrasound attenuation spectroscopy is what is used. Here's a handy project from the D.O.E.
" Characterization of Natural Hydrate Bearing Sediments and Hydrate Dissociation Kinetics "
...remember, processes like extra-corporeal shock wave lithotripsy.?..the process used for kidney stones...
From Wikipedia :
So then with ultrasonic sonar and suspended gas being present there is what's known as " inertial cavitation "
From Wikipedia :
http://en.wikipedia.org/wiki/Cavitation
...so in conclusion to this particularly flatulent post,: :
I think that many of the things we see on the ROV cams can easily be explained with modern scientific knowledge. Hydrate chunks will " swim " as they lose gas, etc.
But one thing I know after all this conjecture for sure....and that's that normal established gas and oil seeps always have other established marine life where they are found.
Always.
If you have any questions just leave a comment if you can't get ahold of me in the chatbox
Thanks for reading my blog, Isaac
Subscribe to:
Posts (Atom)