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 5

Statistics of dynamic core flow tests for acid 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)	Acid fluid			after acidification (×10^-3 μm^2)	(%)		Rank
								Name	Concentration (%)	Content (PV)
S2	692.59	Chang 4+5	3.99	2.49	0.0470	10.18	0.00683	HCL	15	1.0	0.00603	11.7	0.117	Weak
S5	702.39		4.00	2.50	0.637	9.04	0.00359	HCL	15	1.0	0.00291	18.9	0.189	Weak
S31	767.00	Chang 6	3.81	2.49	0.0354	4.91	0.00286	HCL	15	1.0	0.00234	18.2	0.182	Weak
S38	778.92		3.90	2.49	0.194	8.20	0.00549	HCL	15	1.0	0.00469	14.6	0.146	Weak
S40	791.77		3.83	2.49	0.275	8.65	0.0631	HCL	15	1.0	0.0451	28.5	0.285	Weak
S41	760.99		3.79	2.49	0.311	10.19	0.0386	HCL	15	1.0	0.0299	22.5	0.225	Weak