摘要
在研究煤层气单井抽采模型时,首先根据有效应力和渗透率建立相关联系的方法,确立了煤层气固耦合理论方程,然后根据理论分析、数值模拟与常规理论实践规律相结合的方法,考虑了地应力对煤层气解吸、煤层渗透率和孔隙度的相互影响,建立了煤层气运移的数值模型,并观测抽采产量的变化.另外通过理论公式及数值模拟讨论吸附-解吸效应和Langmuir常量对气体压力、渗透率和抽采产量的影响,从而提高抽采产量和生产效率.研究结果表明:(1)煤层气开采过程中,有效应力和吸附-解吸效应都影响着孔隙通道直径的变化,两者存在竞争关系,导致煤层基质产生膨胀或收缩,进而影响渗透率的变化;(2)吸附-解吸效应能够显著提高抽采效率和产量.
Coal bed methane has been received gradually attention because of its small combustion pollution,low cost of development,and huge reserves in the world.Studying the single well extraction model of Coal bed methane,the theoretical formula was fristly deduced separately from the solid field and the seepage field.Then the method of the correlation between effective stress and permeability was established,and the theoretical equation of gas-solid coupling was established.Finally,based on the method of theoretical analysis,numerical simulation and conventional theoretical practice,the interaction between ground stress on coal seam gas desorption,coal seam permeability and porosity was considered,and the numerical model of coalbed methane migration was established,and observing changes in extraction production.In addition,The effects of adsorption-desorption effect and Langmuir constant on gas pressure,permeability and extraction yield were discussed by theoretical formula and numerical simulation,and determining the contribution of desorption effect and Langmuir constant to improve extraction yield and production efficiency.Numerical study and test results both show that:(1)In the process of coal bed methane mining,the effective strain and desorption effect affect the change of the diameter of the pore channel.There is a competitive relationship between the two,which leads to the expansion or contraction of the coal bed matrix,and then affects the change of permeability.(2)The desorption effect can significantly improve the extraction efficiency and yield.
作者
耿玉林
亓宪寅
贾善坡
Geng Yulin;Qi Xianyin;Jia Shanpo(School of Urban Construction,Yangtze University,Jingzhou 434100,China)
出处
《湖南科技大学学报（自然科学版）》
CAS
北大核心
2020年第1期40-48,共9页
Journal of Hunan University of Science And Technology：Natural Science Edition
