Fluid Identification Based on NMR Apparent Free Water Porosity Inversion: A Case Study of Paleozoic Tight Sandstone Gas Reservoirs in Western Ordos

Table 1

Statistical table of the interpretation coincidence rate of the fluid discrimination model in the study area.

Well	Layer	Free water porosity (φffw)	Interpretation conclusion of crossplot method (%)	Interpretation conclusion of apparent free water porosity method	Test results		Interpretation coincidence of crossplot method	Interpretation coincidence of apparent free water porosity method
					Gas (m^3/d)	Water (m^3/d)
E82	P2x8	0.41	Gas layer	Gas layer	22338	0	√	√
E51	Upper part of P2x8	0.22	Gas layer	Gas layer	43374	0	√	√
E40	P2x8	0.66	Gas-water layer	Gas layer	101195	7.5	√	√
E60	Upper part of P2x8	0.74	Gas layer	Gas layer	50591	1.8	√	√
E46	P2x8	0.18	Gas layer	Gas layer	57630	0	√	√
E80	P2x8	0.57	Water layer	Gas layer	24921	48	×	√
E47	P2x8	0.65	Gas layer	Gas layer	22955	30	√	√
E70	Lower part of P2x8	1.24	Gas layer	Gas-water layer	2020	14.4	×	√
E52	Upper part of P2x8	2.38	Water layer	Water layer	902	4.8	√	√
E84	Upper part of P2x8	1.76	Water layer	Water layer	534	23.5	×	×
E78	P2x8	3.49	Water layer	Water layer	109	35	√	√
S175	Upper part of P2x8	0.86	Gas layer	Gas layer	113083	0	√	√
E58	Lower part of P2x8	0.67	Gas layer	Gas layer	25831	0	√	√
E71	Lower part of P2x8	0.75	Gas layer	Gas layer	41330	15	√	√
E67	P2x8	1.34	Gas layer	Gas-water layer	25473	24	×	√
E83	P2x8	1.62	Gas-water layer	Gas-water layer	12412	21.6	√	√
E75	Lower part of P2x8	0.96	Gas-water layer	Gas layer	550	7.3	√	×