论文部分内容阅读
在煤层气井生产后期，随着地层能量的衰竭，井底压力下降，套压逐渐接近集气管网压力，使得井口煤层气不能进入管网。为提高煤层气采收率，对注CO2提高煤层气采收率的机理和CO2注入时机进行了分析，并采用数值模拟方法模拟了煤层气五点井网生产后期将中间的生产井改为CO2注入井后的生产动态。模拟结果显示，注入CO2936．83×104 m3后，能够增产CH4414．50×104 m3，可以提高采收率14．24％，实现煤层中埋存CO2920．51×104 m3。“,”Bottom hole pressure drops as the stratum energy depletes in the late production ,and the casing pressure asymptotically approach-es gas collecting pipe pressure ,which enables the gas not to flow into the pipe .In order to enhance CBM recovery of the later stage ,CO2 injection method in the coal bed is studied .Firstly ,mechanisms of enhancing CBM recovery by CO2 injection are studied ,then injection timing of CO2 injection is analyzed .Finally ,after CO2 is injected into the central well of five spot wells network ,the production performance is simulated by numerical simulation method .The simulation result shows that injection of 936 .83 × 104 m3 CO2 enables the production to increase by 414 .50 × 104 m3 CH4 ,a 14 .24% recovery increase ,realizing the storage of 920 .51 × 104 m3 CO2 .