Effects of Varying Choke Size on Water/Gas Well
Effects of Varying Choke Size on Water/Gas Well
(OP)
Hello,
I'm in a training program for the oil and gas industry.
We've been provided with fictionalized flow rates for a hypothetical water/gas well:
Inches Gas Flow Water Flow
8/64 0.5 MSCF 1600 BBL/Day
16/64 0.3 MSCF 2200 BBL/Day
32/64 0.22 MSCF 3000 BBL/Day
Is it reasonable or possible that the flow rate of gas decreases as the choke size increases? If so, what phenomena causes this...it goes against most of what I know of fluid dynamics that I learned in chemical engineering coursework.
I'm in a training program for the oil and gas industry.
We've been provided with fictionalized flow rates for a hypothetical water/gas well:
Inches Gas Flow Water Flow
8/64 0.5 MSCF 1600 BBL/Day
16/64 0.3 MSCF 2200 BBL/Day
32/64 0.22 MSCF 3000 BBL/Day
Is it reasonable or possible that the flow rate of gas decreases as the choke size increases? If so, what phenomena causes this...it goes against most of what I know of fluid dynamics that I learned in chemical engineering coursework.





RE: Effects of Varying Choke Size on Water/Gas Well
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RE: Effects of Varying Choke Size on Water/Gas Well
We almost never have a really clear picture of all of the flow paths, so if you do an experiment like that and find that closing the choke increases production DO NOT call it a measurement error and open the choke back up like one of my colleagues did, close it a bit more and see what happens.
The change in WGR is probably not physical but an artifact of using SCF. As pressure increases, gas takes up less space so there is more room for largely incompressible water.
David Simpson, PE
MuleShoe Engineering
In questions of science, the authority of a thousand is not worth the humble reasoning of a single individual. Galileo Galilei, Italian Physicist
RE: Effects of Varying Choke Size on Water/Gas Well
In this case it all depends what you're trying to extract - is it gas or water? As the choke opens, and presuming tat pressure d/s of the choke stays more or less the same, then FTHP will decrease and decrease all the way along the well bore until it meets the reservoir rock. As it does that the gas will expand more and lso increase in velocity. As it increase in velocity ti takes more water with it so to speak. Volume of the water is not affected by pressure to any significant degree so more velocity = more flow. Gas on the other hand is greatly affected and hence although velocity might increase, the density reduces amd friction losses increase due to the higher velocity, hence less mass of gas actually makes it to the top.
It can seem counter intuitive, but until you get the whole picture and can convert some of these standard figures into actual velocities and densities, it is difficult to comprehend sometimes.
I have always been told that one thing you don't want to do is go below the reservoir bubble point in a liquid well otherwise gas starts to form in the rock and from what I've been told this is a bad thing. (I will stand to be corrected here though....) Therefore sometimes less (choke size) can be more...
My motto: Learn something new every day
Also: There's usually a good reason why everyone does it that way
RE: Effects of Varying Choke Size on Water/Gas Well
David Simpson, PE
MuleShoe Engineering
In questions of science, the authority of a thousand is not worth the humble reasoning of a single individual. Galileo Galilei, Italian Physicist