Reservoir Sensitivity Analysis of Tight Sandstone and Its Controlling Factors: A Case Study from Chang 4+5 to Chang 6 Reservoirs in N 212 Well Block of Nanniwan Oilfield, Ordos Basin
Table 3
Statistics of dynamic core flow tests for water sensitivity of samples from Chang 4+5 and Chang 6 oil reservoir of N 212 well block.
Sample number
Depth (m)
Stratum
Lc (cm)
Dc (cm)
Kg (×10-3μm2)
Φ (%)
(×10-3μm2)
after 50% dilution (×10-3μm2)
(×10-3μm)
Dw (%)
Rank
S2
692.59
Chang 4+5
4.10
2.49
0.0478
9.43
0.00830
0.00602
0.00465
44.0
Moderate-weak
S5
702.39
3.83
2.49
2.595
12
1.0595
0.8103
0.9886
40.9
Moderate-weak
S31
767.00
Chang 6
3.93
2.49
7.748
14.06
3.3916
2.7028
2.0256
42.0
Moderate-weak
S38
778.92
3.93
2.49
0.188
8.30
0.0130
0.00973
0.00674
48.2
Moderate-weak
S40
791.77
3.81
2.49
0.278
9.50
0.0484
0.0346
0.0259
46.5
Moderate-weak
S41
760.99
3.81
2.49
0.326
10.04
0.0495
0.0359
0.0286
42.2
Moderate-weak
Lc = core length; Dc = core diameter; Kg = gas permeability; Φ = porosity; = formation water permeability; = deionized water permeability; = damage ratio of water sensitivity.
