基于底板构造曲率的煤层高渗区预测

Prediction of higher-permeability region of coalbed methane based on tectonic curvature of coal-seam floor

为预测古交区块8号煤层渗透率,基于最大构造曲率预测煤层裂缝渗透率原理,采用差分法计算煤层底板最大构造曲率,通过分析最大构造曲率、煤层厚度和裂缝间距之间的关系,构建预测煤层渗透率的数值模型。预测结果表明:古交区块煤层渗透率介于0.002~0.650 mD,北部煤层渗透率最高,东部最低;采用该模型预测的煤层渗透率明显高于试验测试的孔隙渗透率,而与试井、试验测试裂缝渗透的结果较为吻合,表明采用此模型预测煤层裂缝渗透率是可行的。

To predict the permeability of No.8 coal seam in Gujiao block,the principle of calculation of coal seam fracture permeability by maximum tectonic curvature was elobrated.The maximum tectonic curvature of coal-seam floor was calculated by the difference method,and a numerical model for predicting coal-seam permeability was established by analyzing the relationship among the maximum tectonic curvature,coal seam thickness and fracture spacing.The prediction results showed that the coal seam permeability in the Gujiao block was between 0.002~0.650 mD,with the highest in the north and the lowest in the East.The permeability of the coal seam predicted by this model was significantly higher than that of the pore permeability tested by the experiment,which was consistent with the result of well test and fracture permeability.It showed that it was feasible to use this model to predict the coal seam fracture permeability.