The Occurrence of Adsorbed Tight Oil and Its Effect on Porosity and Permeability Reduction of Triassic Lacustrine Sandstone Reservoir

Table 1

Sample information and rock mineral composition of Chang 8 reservoir.

Sample	Depths (m)	Mineral composition (%)
		Quartz	Feldspar	Clay	Others	Illite	Chlorite	I/S mixed layer
B455-2-46	2147.87	50.7	39.6	8.6	1.1	28	53	19
B455-2-60	2149.47	50.2	38.0	10.3	1.5	25	58	17
B436-7-33	2192.60	50.3	33.1	12.7	3.9	19	66	25
B436-7-38	2193.20	50.2	34.2	11.8	3.8	14	64	22
B456-6-6	2134.20	50.0	36.3	12.2	1.5	11	75	14
B280-13-3	2213.35	49.8	32.0	13.8	4.4	5	83	12

Others: calcite+dolomite+pyrite; I/S mixed layer: illite and smectite mixed layer.