A pressure build-up test was conducted in an oil well which is centred in a squared reservoir. The following formation and fluid properties are known:
q = 55 STB/D Area= 160 Acres
; tp = 1440 hrs; re = 1320 ft; ɸ = 28%
rw =0.29ft; B=1.136RB/STB; ct =9.68×10-6 psi-1; μ=8.7cp h = 50 ft
;
The test data is shown as under:
Shut-in time (hours) Pressure (psi)
Shut-in time (hours)
Pressure (psi)
0 2162.11 7.74 2326.31
0.050 2202.30 9.33 2327.72
0.110 2234.27 11.25 2329.10
0.182 2258.66 13.55 2330.45
0.268 2276.35
16.31
2331.79
0.372 2288.59
19.62
2333.09
0.496 2296.80 23.60 2334.37
0.646 2302.29
28.4
2335.62
0.825 2306.12 34.1 2336.84
1.040 2309.01 41.0 2338.02
1.298 2311.38 49.2 2339.17
1.608 2313.45 59.1 2340.26
1.979 2315.34
71.0
2341.29
2.42 2317.10 85.2 2342.25
2.96 2318.77 102.3 2343.13
3.60 2320.37 122.8 2343.92
4.37 2321.91 147.4 2344.59
5.30 2323.41 177.0 2345.15
6.41 2324.88 196.0 2345.41
Tasks:
- Use Horner analysis to estimate formation permeability and skin factor
- Use MBH, MDH and modified Muskat Method to estimate average drainage
area pressure. - Estimate initial reservoir pressure using MDH method
- Compare the results obtain in part 2) and comment on the accuracy of each
method.
Question # 02: Estimation of formation permeability, skin factor and reservoir pore volume
A new well was drilled in a closed reservoir and a 7-day flow test was run.
q = 435 STB/D; pi = 1701.09 psia; ɸ = 27%
rw =0.31ft; B=1.138RB/STB; ct =9.8×10-6 psi-1; μ=2.305cp h = 50 ft.
Time (hours) Pressure (psi) Time (hours) Pressure (psi)
0.01 1656.73
3.56
1517.88
0.0222 1625.93 4.36 1515.23
0.0371 1604.46 5.33 1512.58
0.0552 1589.60 6.51 1509.92
0.0774 1579.19 7.95 1507.23
0.1044 1571.60 9.71 1504.46
0.1374 1565.75 11.86 1501.57
0.1776 1560.94 14.48 1498.50
0.227 1556.76 17.67 1495.19
0.287 1553.00
21.6
1491.58
0.360 1549.52
26.3
1487.58
0.449 1546.24 32.1 1483.10
0.557 1543.11 39.2 1478.00
0.690 1540.09 47.8 1472.08
0.852 1537.15 58.4 1465.10
1.049 1534.29 71.2 1456.77
1.290 1531.47 86.9 1446.70
1.584 1528.70 106 1434.49
1.943 1525.96 129.4 1419.60
2.38 1523.25 157.8 1401.45
2.91 1520.56 168.0 1394.97
Tasks:
- Estimate the formation permeability and skin factor
- Estimate the reservoir pore volume