Hi,

I have currently moved to a Production Engineer role and have been doing some self study to brush up on my skills. A question I have been working on has been giving me some problems and I was hoping that someone could assist me. The problem is below:

The following production data pertains to a reservoir where the current average reservoir pressure is unknown. The well is equipped with a 7000 ft of 2 7/8 in (ID=2.441 in) tubing and the required wellhead pressure is 160 psi. The well is producing at a rate of 1000 stb/d when the flowing bottom hole pressure is 2184 psi. The current producing gas/liquid ratio is also recorded as 400 scf/stbl and no water produced. A recent isochronal test results revealed the following reservoir performance parameters.

C=0.005 stbl/day-psi
n=0.8

Other relevant information are as follows:

Gas Gravity: 0.65, Oil API Gravity: 35, Water Specific Gravity: 1.07, Average Flowing Temperature: 150 F

Determine the oil production capacity of the well (STBO/D) when the reservoir pressure drops down to 2000 psi and with 50% water production and a producing GLR of 600 scf/stb is anticipated.

I know that that the questions involves using VLP curve and believe that the back pressure equation q=c(Pr^2 - Pwf^2)^n. Any input/direction or if possible a solution would be greatly appreciated.

Thanks for all help.

Regards,