注气提高煤层甲烷采收率机理及实验研究

该文讨论了采用注气方法提高煤层甲烷采收率的机理,认为注入的气体在增加储层能量的同时,还可以与煤层甲烷产生竞争吸附或置换驱替效应,从而提高煤层甲烷的采收率。通过煤对纯甲烷气体和甲烷-氮气、甲烷-二氧化碳二元气体的等温吸附和解吸实验,分别获得了它们的Langmuir方程,并对它们的理论最大采收率进行了对比分析。结果表明,在含气量相同的情况下,煤层中二元气体的理论最大采收率比纯煤层甲烷的理论最大采收率要高得多。

STUDY ON THE EXPERIMENT AND MECHANISM OF RAISING THE RECOVERY RATIO OF COALBED METHANE BY GAS INJECTION

In this paper,the mechanism of raising the recovery ratio of coalbed methane by gas injection was discussed.It was considered that injected gases not only enhanced reservoir energy.but also completed with coalbed methane for adsorption or replaced and expelled coalbed methane.As a result,the recovery ratio of coalbed methane was raised.By the isothermal adsorption and desorption experiments of coal samples to pure CH₄ gas as well as CH₄-N₂ and CH₄-CO₂ two binary gases,their Langmuir equations were obtained respectively,and their maximum theoretical recovery ratio was compared and analysed.The results revealed that the maximum theoretical recovery ratio of binary gases in coal beds was much higher than that of pure coalbed methane under the condition of the same gas content.