A vertical well of 8000 ft is producing below bubble point pressure

Q. A vertical well of 8000 ft is producing below bubble point pressure. Oil and water each is produced at the rate of 500 bbl/day. The indicated bottom hole pressure is 3000 psi. If the same gas to liquid ratio (GLR) is maintained, using the given figure, the new bottom hole pressure at 5000 ft is ______psi.

Ans: 1600-1900

Sol:

As per the pressure gradient curve determine GLR for depth 8000 ft with BHP as 3000 psi. Now after finding the GLR curve use the same GLR curve move upward along the curve to a depth of 5000 ft and draw a vertical line from that point on the GLR curve at 5000 ft to reach 1750 psi as BHP.