3. a field is a combination-drive reservoir. the current reservoir pressure is estimated at 2500 psi. the reservoir production data and pvt information are given below:

initial reservoir condition

current reservoir condition

p, psi

3000

2500

bo, bbl/stb

1.35

1.33

rs, scf/stb

600

500

np, mmstb

0

5

gp, mmmscf

5.5

bw, bbl/stb

1.00

1.00

we, mmbbl

0

3

wp, mmbbl

0

0.2

bg, bbl/scf

0.0011

0.0015

cf, cw

0

0

the following additional information is available:

volume of bulk oil zone = 100,000 ac-ft

volume of bulk gas zone = 20,000 ac-ft

calculate the initial oil in place. (25 points)