热力耦合条件下超临界CO2驱替煤层CH4实验

为提高煤层CH₄抽采效率，利用自主研发的实验系统，模拟超临界CO₂在深部煤层中驱替CH₄的过程，开展了不同温度和注入压力条件下原煤试样中超临界CO₂渗流、吸附及驱替CH₄实验。结果表明:在恒定温度条件下，随着超临界CO₂注入压力逐渐增大，煤体渗透率提高，CO₂吸附量增加。超临界CO₂注入压力和温度对驱替效果影响显著。不同温度条件下，当超临界CO₂注入压力从8 MPa增至12 MPa，CH₄驱替量平均增长了0.076 cm3/g，CH₄驱替效率增加了17%~23%，超临界CO₂置换体积比呈线性递减趋势；相同注入压力条件下，温度每升高10℃，驱替效率平均增加8%，置换体积比平均下降0.5。研究结果为高效抽采煤层CH₄和实现CO₂封存提供理论依据。 

Experiment on methane displacement in coalbed by supercritical carbon dioxide

Using self-made experimental system, experiments were performed on coal samples to study supercritical CO₂ seepage, adsorption and CH₄ displacement by supercritical CO₂. Experimental results show that permeability and adsorption of supercritical CO₂ in coal increase with CO₂ pressures. Pressures and temperatures of CO₂ influence the values of displaced CH₄. Values of displaced CH₄ increase by average 0.076 cm3/g and sweep efficiency rises by 17%-23% with the CO₂ pressure increasing from 8 MPa to 12 MPa, while displacement volume decreases linearly. With the temperature rising by 10℃, sweep efficiency increases by 8% while displacement volume declines by 0.5 on average.