College of Geosciences and Surveying Engineering, China University of Mining and Technology (Beiing) School of
Energy Science and Engineering, Henan Polytechnic University

基于煤层渗透率变化对提高煤层气采收率的重要性,研究了煤中矿物质与CO2反应引起的煤层渗透率随时间变化以及渗透率的改善效果。结果表明:煤体渗透率随CO2注入时间的增加呈现出先增大后减小的趋势,渗透率变化量最大值出现在注入CO2后的1.75个月左右;煤储层中注入CO2对原始渗透率较低或较高的煤层改善效果都不理想,而对中等原始渗透率(0.303 6~3.099 0)×10-3μm2的煤层改善效果较好。最后通过分析渗透率与孔隙度随时间的关系,建立了R-R型、I-R型、I-I型3种孔隙度-渗透率关系模型,其中,I-I型对煤层气开发最为有利。

According to the importance of permeability change in enhancing coalbed methane ( ECBM) recovery, the paper studied the permeability change laws al ong with time and its improved effects induced by the reaction CO 2 injection and minerals in coal. The results showed that the permeability increased at first and then t urned up to decrease along with CO 2 injection, the maximum value of permeability change appear after 1. 75 months. The improvement of permeability was not obviou S to too small or too big initial seam permeability, while the medium seam permeability( 0.3036~ 3.099 0) x 10- 3μm2improvement was the best. Finally, the paper bu ilt three kinds relationship model ( R- R type、|- R type、|- I type) between permeability and porosity of seam by analyzing the change relationship between permeabilit y and porosity with time to different coal samples. Accroding to analysis results, |- | type was the best to coalbed methane development.

国家科技重大专项资助项目(2011ZX05042-03；2011ZX05034-05)；