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Boost Pressure in Line

Boost Pressure in Line

Boost Pressure in Line

(OP)
Hello!

I have a random mixture of oil, natural gas, and brine being pumped out of pump jacks. We have to run the pump jacks very inefficiently because this mixture has to be pumped 10km to our processing facility at a pressure of 20psi. We would like to put some kind of booster mid way through the line to push the oil, gas and brine mixture along, thus allowing us to run the pump jacks at lower power. Can anyone think of a pump or system that can push the mixture through this line. I have looked into 3 phase flow pumps and see their prices (around $200,000) and am looking for something a little more economical. The mixture runs through a 6" steel pipe.
Let me know what you think!

Thanks

RE: Boost Pressure in Line

The absolute least expensive option is to apply some backpressure (about 100 psig, 150 psig is better) at the tail end of the pipe.  At 20 psig, the gas is taking up too much volume and you are experiencing very large drag effects.  Raising the pressure at the tail end of the process will squash the gas back down to where it flows at closer to the speed of the liquids and doesn't waste power trying to drag it along.  I know this sounds wrong, but every time I've done it the pumping power required has gone down significantly.  

The next least expensive option is to install my (patented) GasBuster (animation at bottom of right column) to pull the gas out of the stream prior to entering the 6-inch, but you need to have a place to put it then too (although, you can just stuff it back down the annulas).  I'd still keep 150 psig on the pump discharge to get it back up to where it is supposed to be.

A transfer pump is really a bad idea unless there is some place you can dump the gas.

David Simpson, PE
MuleShoe Engineering

"Belief" is the acceptance of an hypotheses in the absence of data.
"Prejudice" is having an opinion not supported by the preponderance of the data.
"Knowledge" is only found through the accumulation and analysis of data.
The plural of anecdote is not "data"

RE: Boost Pressure in Line

Kind of depends on what your mixture actually is, do you have gor or cgr figures or flow rates?

Why put it half way?. You could build something at your existing facility much easier.

Typically this would be a two phase separator with pump and compressor feeding both fluids into a single line. At that sort of pressure and flow I'm sure it will be a lot cheaper than a true multiphase pump.

If you have lots of gas you can get a boot type system which collects the liquid, compresses the gas in a compressor and every now and then via some valving purges the boot into the d/s line. I'll draw it up later.

This won't be an uncommon issue so there may be ready made skids available new or second hand to do exactly this duty.

My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way

RE: Boost Pressure in Line

Isn't it great working without numbers such as reservoir pressure, bubble point, gor, flow rates etc. I agree with zdas that when it comes to three phase flow the most obvious answer - lower the pressure- has strange effects. You want to get your downhole pump pumping liquid, not gas and a bit of liquid.

What often isn't factored in is the amount of low c number components which come out of the crude when the pressure comes down. Providing you've got a reasonable amount of liquid, I always aim for an actual gas velocity of 3 to 5 m/sec. Less and you get too much liquid holdup, too fast and you loose to much due to friction losses.

You can do some fancy number crunching and analysis, but you can do some of your own tests much more easily and work out what is right for your well. Zdas has the history and experience. Take good note of it.

My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way

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