Petroleum reservoir

1. Applied Reservoir Engineering Course
‫النفطية‬ ‫المكامن‬ ‫هندسة‬ ‫تطبيقات‬
PE444

2. Lecture No. 6
‫المحاضرة‬
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6
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3. Material-Balance Equations for
Oil Reservoirs

4. Material-Balance Equations for Oil Reservoirs

5. Cases to be considered

6. Case 1
- Undersaturated Reservoirs
- Reservoir Pressure Always above the Bubble Point Pressure

7. MBE for Oil Reservoirs Producing above the Bubble Point

12. Example:
Given a reservoir above the bubble point pressure (Pb= 1276 psia) with negligible aquifer support. The
initial average reservoir pressure was 5519 psia. After 2.4 MMstb of oil and 0.24 MMbbl of water were
produced, the average reservoir pressure decreases to 2148 psia. PVT data as follows:

13. Solution:

14. (b): using eq. (III.5)

15. (c): if cw=0, cf=0
The water and rock compressibities should not be ignored

16. Example:
Repeat the previous example with the following modifications:
The cumulative oil production and water production were 5.5 MMstb and 0.4 Mmstb,
respectively, as the average reservoir pressure declined to 3571 psia.
Estimate the OOIP and the recovery factor?

17. Example:

18. Solution: