注二氧化碳提高煤层气采收率实验系统设计

Experimental system design for CO2 enhanced coalbed methane recovery

针对我国煤层气开发中存在的产气率低、回采周期长的问题以及CO2排放量大、污染环境严重等现象,研制了一套可以进行煤层气吸附/解吸性能评价及注CO2开采煤层气模拟的实验系统。利用该系统开展了不同气体在煤岩中的吸附/解吸性能评价研究和注CO2开采煤层气效果实验研究。实验结果表明,CO2在煤岩中的吸附量明显高于CH4的吸附量;与自然降压开采相比,注CO2可以提高煤层气的采收率,提高幅度在10%以上。而且随CO2注入量的增加,煤层气采收率增大。

The production rates of coalbed methane wells are lower for the special properties of coalbed and coal,compared with those of other countries.CO2 emission will result in a serious enviromental problem.A new experimental system was designed to evaluate the adsorption and desorption properties of different gases in coalbed samples and to simulate the method of enhanced coalbed methane recovery by CO2 injection.The adsorption and desorption properties of different gases were measured by using this equipment.Experiments of displacment of methane by CO2 injection were conducted and compared with pressure decreasing method.Experiments show that CO2 can be easily adsorbed to the coalbed samples,compared with methane.The gas recovery rate of CO2 displacement increases more than 10%,compared with that of pressure decreasing method.The gas recovery rate increases with the increasing of the injected volume of CO2.The different adsorption properties of CO2 and methane can be one of the mechanisms foe gas recovery rate increasing.