Experimental Study on the Effect of Supercritical CO₂ on Mechanical Properties and Fracture Characteristics of Longmaxi Shale

Table 4

Mineralogical analysis results of the three experiments (XRD).

Test name	Mineral contents (%)
	Quartz	Feldspar	Plagioclase	Calcite	Dolomite	Clay and other minerals
scCO2 test	33.5	0.4	0.6	16.1	27.1	22.3
	38.2	0.4	0.4	14.5	25.8	20.7
	28.4	0.3	0.9	16.8	29.3	24.3
	34	0.4	0.4	15.2	27.7	22.3
	31.3	0.6	0.6	16.4	26.4	24.7
	32.9	0.6	0.4	16.9	27.9	21.3
	32.2	0.4	0.6	16.1	28.4	22.3
N2 test	22.1	0.5	0.8	22.1	33.1	21.4
	21.6	0.5	0.7	23.5	34.7	19
	23.4	0.6	0.4	22.4	32.7	20.5
	22.5	0.4	0.6	22.7	33	20.8
	23.2	0.6	0.4	23.8	32.7	19.3
	23.4	0.5	0.6	23.4	33.5	18.6
	22.9	0.7	0.6	23.6	32.9	19.3
Helium test	24.5	0.6	0.6	23.2	35.7	15.4
	23.7	0.5	0.8	22.6	33.2	19.2
	22.3	0.7	0.7	22.5	33.8	20
	23.2	0.5	0.6	23.8	34.3	17.6
	22.9	0.6	0.9	23.1	35.1	17.4
	23.1	0.5	0.5	23.3	34.9	17.7
	22.8	0.7	0.5	23.6	33.5	18.9