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 4

Statistics of dynamic core flow tests for salt sensitivity of samples from Chang 4+5 and Chang 6 reservoirs of N 212 well block.

Sample number	Depth (m)	Stratum	Lc (cm)	Dc (cm)	Kg (×10^-3 μm^2)	Φ (%)	(×10^-3 μm^2)	after dilution (×10^-3 μm^2)		(×10^-3 μm)	Critical salinity (mg/L)	Rank
								50%	25%
S2	692.59	Chang 4+5	3.80	2.50	0.0456	9.61	0.00410	0.00287	0.00240	0.00213	18939	Moderate-strong
S5	702.39		3.82	2.50	0.617	9.52	0.0284	0.0214	0.0196	0.0171	18939	Moderate-strong
S31	767.00	Chang 6	3.80	2.49	0.0309	5.95	0.00130	0.000922	0.000819	0.000677	18507	Moderate-strong
S38	778.92		3.99	2.49	0.199	8.25	0.00760	0.00552	0.00483	0.00434	18507	Moderate-strong
S40	791.77		3.89	2.50	0.214	9.44	0.0817	0.0621	0.0520	0.0461	18507	Moderate-strong
S41	760.99		3.82	2.49	0.281	9.48	0.0440	0.0311	0.0268	0.0238	18507	Moderate-strong