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为观察含CH_4煤岩注入CO_2后力学和渗透性能的变化,用自制三轴吸附解吸渗流试验装置开展试验,研究型煤试件内气体种类和注气压力对注CO_2煤岩强度、渗透性和应变等参数变化的影响。试验结果表明:含CH_4煤岩注入CO_2后,单轴压缩应力-应变曲线与未注入CO_2的总体变化趋势相同,但煤岩强度等参数随注气压力的变化而变化。注入等孔隙压CO_2后,含CH_4煤岩的强度和弹性模量均明显上升,但煤岩中CH_4渗透率呈现下降趋势;随着CO_2注入压力的增加,煤样的强度和弹性模量逐渐下降,而CH_4渗透率逐渐增强,注气压力每增加1 MPa,煤岩强度平均下降0.095MPa,CH_4气体渗透率平均增加1 m D。
In order to observe the change of mechanical and permeability properties of CH_4-bearing coal after CO_2 injection, a self-made three-axis adsorption-desorption seepage test device was used to test the effect of gas type and gas injection pressure on the strength, Strain and other parameters change. The experimental results show that the uniaxial compressive stress-strain curve shows the same trend as that of uncooled CO_2 after the injection of CO_2 into CH_4-bearing coal, but the parameters such as the strength of coal and rock vary with the injection pressure. After injecting equal pore pressure CO_2, the strength and elastic modulus of CH_4-containing coal rock obviously increase, but the permeability of CH_4 in coal rock shows a downward trend. With the increase of CO_2 injection pressure, the strength and elastic modulus of coal sample gradually decrease , While the permeability of CH_4 gradually increased. For each additional 1 MPa gas injection pressure, the average strength of coal and rock decreased by 0.095 MPa and the average permeability of CH_4 gas increased by 1 mD.