注二氧化碳提高煤层甲烷采收率的实验模拟

A Modeling Experiment of Enhancing Coalbed Methane Recovery by Carbon Dioxide Injection

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,开展了注二氧化碳驱替煤层甲烷的实验模拟研究.根据实验数据,利用扩展Langmuir方程计算了驱替过程中CH4组分的产出特征,并与纯CH4的解吸过程进行了比较.结果表明,在CO2驱替实验中,CH4在单位压降下的解吸率,明显高于纯CH4解吸时单位压降下的解吸率.其中晋城煤层CH4单位压降下的解吸率提高了150%,潞安煤层CH4单位压降下的解吸率提高了270%.由此可见,采用二氧化碳注入技术,可以显著提高煤层甲烷的采收率.

In accordance with the problem of lower productivity and longer recovering period in coalbed methane exploitation of China, a modeling experiment of carbon dioxide displacing coalbed methane was accomplished. On the basis of experimental results, the production characteristics of CH4 in displacing process was calculated using the extended-Langmuir equation. The compare research between displacing process and pure CH4 desorption process was carried out. The results indicate that the desorption rate of CH4 at unit pressure drop in the process of carbon dioxide displacement is obviously bigger than that in the process of pure CH4 desorption. The coalbed methane desorption rate at unit pressure drop of Jincheng coal was increased by 150%, and that of Lu＇an coal was increased by 270%. Hence, the recovery of coalbed methane can be efficiently enhanced by carbon dioxide injection.