Reservoir characteristics and genetic mechanisms of gas-bearing shales with different laminae and laminae combinations: A case study of Member 1 of the Lower Silurian Longmaxi shale in Sichuan Basin, SW China

SHI Zhensheng,DONG Dazhong,WANG Hongyan,SUN Shasha,WU Jin

Table 1 Statistics of porosity and permeability of various lamina combinations in gas-bearing shale in Long-1 Member, Shuanghe outcrop, Sichuan Basin.

Lamina combinations	Sample No.	Net porosity/%	Mean net porosity/%	Permeability/10^-3μm²		Ratio of horizontal to vertical permeability
Lamina combinations	Sample No.	Net porosity/%	Mean net porosity/%	Vertical	Horizontal	Ratio of horizontal to vertical permeability
Siltstone bearing laminae combination	8-10-1	9.04	6.49	0.025 925	0.223 540	8.62
	8-31-2	4.13		0.000 351	0.002 291	6.53
	9-11-1	6.31		0.000 620	0.004 737	7.64
Graded (siltstone to claystone) laminae combination	9-16-1	5.76	4.85	0.000 369	0.001 373	3.72
	9-19-1	6.17		0.000 834	0.003 803	4.56
	9-19-2	5.98		0.000 288	0.001 351	4.69
	9-21-1	2.17		0.000 279	0.000 879	3.15
	9-21-2	4.17		0.000 376	0.001 304	3.47
Siltstone and claystone interlaminated laminae combination	9-23-1	2.63	2.39	0.000 239	0.000 509	2.13
	10-7-2	2.73		0.000 216	0.000 318	1.47
	10-8-1	2.29		0.000 116	0.000 309	2.66
	11-2-1	2.48		0.000 101	0.000 201	1.98
	11-2-2	1.83		0.000 159	0.000 405	2.54