煤样尺度的二氧化碳驱替煤层气数值模拟  

Numerical simulation of CO_2-ECBM based on coal sample scale

作　　者：王伟[1,2] 方志明 李小春[1,2] WANG Wei;FANG Zhiming;LI Xiaochun(State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics,Chinese Academy of Sciences,Wuhan 430071,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院武汉岩土力学研究所岩土力学与工程国家重点实验室,湖北武汉430071 [2]中国科学院大学,北京100049

出　　处：《中国矿业》2019年第2期121-125,共5页China Mining Magazine

摘　　要：为了实现ECBM实验研究和数值模拟结合分析,基于实验室应力条件的渗透率模型,建立了煤孔隙裂隙介质系统的CO2驱替煤层CH4的数值模型。开展了不同CO2注入压力下煤样尺度的二氧化碳驱替煤层气的数值模拟。结果表明:CO2的注入压力越大,注入后CO2从煤样末端流出所需时间越小;CO2的注入会引起煤的渗透率减小,注入压力较小时渗透率变化分为三个阶段,包括有效应力影响的阶段、CH4压力不变的阶段和CO2吸附影响阶段,但是当注入压力较大时则不存在CH4压力不变的阶段;注入压力增大,CH4产出量在注入CO2后的一定时间内有很大提高,然后在注气后期,CH4产出量反而较小。上述结果对指导室内开展ECBM实验和分析ECBM室内实验的结果具有指导意义。In order to achieve the ECBM experimental research and numerical simulation combined analysis,based on the permeability model under the laboratory stress conditions,a numerical model of CO 2-ECBM,including the pore and fracture medium system of coal,was established.Numerical simulation of CO 2-ECBM at different CO 2 injection pressures was carried out.The results show that the greater the injection pressure of CO 2,the less time it takes for CO 2 to flow out from the end of the coal after injection.The injection of CO 2 will cause the permeability of coal to decrease,and when the injection pressure is small,the change of permeability will be divided into three stages,including the stage of effective stress,the stage of constant CH 4 pressure,and the stage of CO 2 adsorption.When the injection pressure is large,there is no stage of the stage of constant CH 4 pressure.As the injection pressure increases,the CH 4 output increases greatly after a certain period of time after the injection of CO 2,and then the CH 4 output is smaller at the later stage of gas injection.The above results are instructive for the CO 2-ECBM experiments and the analysis of its experimental results.

关 键 词：ECBM数值模型 渗透率模型 注入压力 煤层气产量 

分 类 号：TD712[矿业工程—矿井通风与安全]