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 ?
" 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. "

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.

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, 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...

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

I would be interested to know about the transducers they used on the stack, purely out of dense-headed curiosity.

A little bonus paper :

It's all about the groovy ...Here's another paper that illustrates what I am talking about.


 ....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 ?

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