Study on a New Rock Fracability Evaluation Model of Shale Gas Reservoir

Table 1

Shale mineral composition characteristics of Wufeng-Longmaxi formation.

Sample	Formation	Depth (m)	TOC (%)	Quartz (%)	K-feldspar (%)	Plagioclase (%)	Calcite (%)	Dolomite (%)	Pyrite (%)	Ankerite (%)	Clay mineral (%)
1	Longmaxi	1399.47	0.94	32.9	2.6	6.6	10.3	9.8	0.9	4.4	32.5
2	Longmaxi	1875.68	0.48	13.9	0	4.3	40.8	7.6	0.9	9.1	23.4
3	Longmaxi	1934.25	0.52	24.6	1.3	4.2	21.8	8.6	0.8	6.6	32.2
4	Longmaxi	2054.63	5.45	47	0	3.4	13	11.2	1.8	5.6	18
5	Longmaxi	2062.88	2.40	30.2	1	2.4	27.8	6	0	6.1	26.6
6	Longmaxi	2164.24	1.92	35.9	1	6.3	6.9	3.2	1.9	3.1	41.7
7	Longmaxi	2174.36	2.71	34	1.2	2.8	13.1	3.3	1.4	0	44.1
8	Longmaxi	2177.01	2.50	41.5	0	1.9	14.3	0	1.9	0	40.5
9	Wufeng	2200.92	7.79	47.1	0	6.6	7.6	5.8	1.8	4.5	26.6
10	Wufeng	2205.24	3.28	54.2	0	1.6	12.5	2.9	0	2.8	26
11	Wufeng	2285.55	2.81	25.3	1.1	2	28.3	19.3	2.6	13.3	8.2
12	Wufeng	2287.34	1.74	25.7	0.8	1.7	30.7	12.3	2.6	10.2	16
13	Baota	2293.97	0.90	20.1	1.7	5.8	26.6	1.9	0.9	4.2	38.7
14	Longmaxi	2507.35	—	—	—	—	—	—	—	—	—
15	Longmaxi	2508.57	—	—	—	—	—	—	—	—	—
16	Wufeng	2512.11	4.85	27.3	1	4.8	24.2	14.4	2.3	12.1	14