Experimental Study on the Effect of Long-Term Water Injection on Micropore Structure of Ultralow Permeability Sandstone Reservoir

Table 4

Permeability and porosity information.

Cores	Water flooding stage (PV)	Injection pressure (MPa)	Permeability (mD)	Total signal amplitude	Porosity (%)
C9-2	0	0.12805	0.365	1407.48	10.42
	200	0.12951	0.347	1410.18	10.44
	400	0.12994	0.342	1422.34	10.53
	600	0.13003	0.341	1426.39	10.56
C11-2	0	0.12736	0.378	1528.85	10.84
	200	0.13115	0.332	1531.67	10.86
	400	0.13325	0.311	1537.31	10.90
	600	0.13347	0.309	1540.13	10.92