The Evolution of Diagenetic Fluids and Accumulation Characteristics of Tight Sandstone Reservoir in Upper Paleozoic, Southwestern Ordos Basin

Table 1

Whole-rock X-ray diffraction analysis of sandstone and clay in the Upper Paleozoic of the study area.

Well number	Depth (m)	Stratum	Sample number	Whole-rock X-ray diffraction analysis of mineral relative content (%)							Clay mineral relative content (%)
				Amount of clay	Quartz	Ankerite	Graphite	Siderite	Anatase	Not detected	Illite	Kaolinite
Xiang 1 well	2554.77	Zhifang Formation	1	31	52	11		5	1	0	61.06	38.94
Qingtan 2 well	4731.5	Shan 1	2	26	65	5		2	1	1	67.00	33.00
He 3 well	4146.62	Shan 2	3	15	61	18	1	2	2	1	87.89	12.11
Zitan 1 well	3742.50	He 8	4	21	49	23		5	1	1	58.41	41.59
Ling 1 well	3697.14	Shan 1	5	37	44	14		2	1	2	66.55	33.45
Lian 1 well	3470.03	Shan 1	6	39	54	2		2	2	1	56.08	43.92
Average				28.3	54.2	12.2		3.0	1.3	1.0	66.17	33.83