A volumetric gas field has an initial pressure of 4200 psia, a porosity of 17.2% and a

connate water saturation of 23%. The gas volume factor at 4200 psia is 0.003425 and

ft³

SCF

ft³

SCF

at 750 psia is 0.01852

a) Calculate the initial gas in place (GIP) in standard cubic feet (SCF) on a unit basis.

b)

Calculate the initial gas reserve in SCF on a unit basis, assuming an abandonment

pressure of 750 psia.

Explain why the calculated initial reservoir depends on the abandonment pressure.

Calculate the initial reserve of a 640-acre unit whose average net productive formation

thickness is 34 ft, assuming an abandonment pressure of 750 psia.

e) Calculate the recovery factor based on an abandonment pressure of 750 psia.

c)

d)

4.1