Gas Interference in horizontal oil wells 1

[hajoges]

I have high fluid levels in a pumping horizontal oil well. (1300' from surface). I am set to pump 200 bfpd with a 1.5" RWAC pump, but the pump efficiency is low, between 50- 60%. We think we may have gas interference in the pump because of the nature of our fluid (light foamy oil (45 Deg API)). Somebody has recommended installing a backpressure regulator to maintain constant pressure on the oil column within the tubing, let’s see. Any other ideas or thoughts.
Regards

 

[bcs5274]

i am currently workin on a couple gas lift projects in the bakken with good success, using the gas produced by the well with a 200 hp 3 stage compressor

 

[zdas04]

Every kind of pump will work best with a predictable, constant discharge pressure. What I've found is that at 3,000 ft if I'm pumping water, the discharge pressure should be around 1,300 psig. If I have near zero psig on the tubing, it is 1,300 psig as long as there is no free gas in the discharge stream. Add as little as 1 MCF/d and (with zero psig surface pressure) the pump discharge drops to under 50 psig because of the space required for 1 MCF/d. If I add 200 psig back pressure then the pump discharge goes to some value above 1,200 psig.

Pumping light oil is even worse because of the certainty of phase change at low pressures.

With a sucker-rod pump, if it ever gas locks then leakage past the plunger is required to break the gas lock. With 1,200 psig pump discharge you'll break the gas lock in something like 6 hours. With 50 psig it will take closer to 6 days.

With your drop in effeciency, I'd say that the standing valve is only opening 1/2 to 2/3 of the strokes. Yeah, I'd recommend a back-pressure valve.

David

 

[hajoges]

Guys,
Thanks for your answers. We've installed tubing regulators on our wells and set those to hold 200 psi on the tubing. As of today, the line pressure is 128 psi and wellhead pressures are tbg 200 psi and Csg 130 psi. So far I havent seen any production changes in the last 3 days.

David, do you think we should hold more than 200 psi? is there a good way to calculate this number?

bcs5274, are you re-circulating the well, could u please elaborate some more.

Thank you guys!!!

 

[bcs5274]

we are taking the gas that comes up with the fluids and pushing into the casing of the well to increase reservoir pressure, the suction of the compressor is pulling on the tubing, working as a velocity string to aid in production and get away from epa issues with continuous flaring of gas in an area with no gas pipelines

 

[zdas04]

The calculation at each pressure is quite tedious and doesn't change much with small changes in pressure. The data is a bit sparse, but I think that there is a sweet spot around 100 psig over casing pressure--not sure I have an explaination for that number but, a value somewhere around there seems to maximize production.

If you saw a change in a couple of days, I'd say that you are applying way too much wishful thinking to your analysis. Look at it in a couple of months.

David