地应力、地温场中煤层气相对高渗区定量预测方法

为定量化预测煤层气高渗区，以应力、温度影响下的煤层气压力、孔隙率和渗透率的预测方程为基础，提出了地应力场、地温场中煤层气渗透率预测的定量化方法，建立了考虑煤体内部裂隙结构和应力、温度影响的渗透率计算方法，给出了实验室渗透率与现场实测渗透率的校正方法.通过Kaiser声发射原岩应力测试实验、不同温度不同围压条件下煤体甲烷渗流实验、孔隙率测定实验、比表面积测定实验、煤体压缩及热膨胀实验，研究了应力、温度影响下的煤体甲烷渗透规律.研究发现，煤体甲烷渗透率随温度变化并非单调递增或单调递减，渗透率与温度的关系，取决于外围有效应力条件或围压条件，即高有效应力时，煤体具内膨胀效应，渗透率随温度升高而降低；低有效应力时，煤体外膨胀，渗透率随温度升高而升高.依据理论方程和实验，以等值线形式定量预测了重庆沥鼻峡矿区煤层渗透率分布，并划定了相对高渗透区，解决了当前煤层气高渗透区预测难以定量化的问题，并提高了预测精度.

Quantitative predicting method of coalbed methane relative high permeability region in geo stress and geothermal field

In order to predict high permeability zone of coalbed methane quantitatively and accurately, based on prediction equation of gas pressure, coal porosity and permeability influenced by stress and temperature, quantitative prediction method of gas permeability was provided in geo stress and geothermal field. Calculation method of permeability was established considering pore structure, stress and temperature. Corrector method of permeability was given between experiment and actual measurement. Experiments of Kaiser AE stress testing, seepage flow at different temperature and stress, BET surface testing, coal compress testing and heat expansion testing were carried out. The results show that the relationship between permeability and temperature depends on effective stress conditions. Methane permeability in coal decreases with temperature increasing at high effective stress, contrarily, increases with temperature increasing at low. Based on the theory equations and experiments, permeability distribution of Chongqing Libixia mining area in China was predicted quantitatively. Relative high permeability zone was delimited. The quantification problem of high permeability zone prediction was solved; the permeability prediction precision of coalbed methane was improved.