用热采模型模拟煤层气开采过程

COAL-BED GAS PRODUCTION PROCESS SIMU-LATION BY USE OF THERMAL MODEL

流体在煤层中的传输机理包括：气体在煤内表面解吸，并通过基岩和微孔隙扩散进入裂缝网络中。若岩块表百甲烷气体的释放速度比气、水相在煤层割理中的流动速度快得多，那么在模拟煤层气开采过程时，解吸动能是可以不考虑的。这个假设允许吸附在煤层表面上的甲烷气可以作为溶解在非流动油中的气体来模拟；煤层中的朗格缪尔等温曲线可视为常规油藏中的溶解气油比曲线。可用常规油藏模型描述煤层气，而不需要对模型源码做任何修改。基于上述思路，用热采模型模拟煤层气开采过程，并与用煤层气模拟软件（ＣＯＭＥＴＰＣ）的计算结果进行了比较，趋势非常接近。

The transportation of gas through a coal seam includes the desorption of gas from the coal matrix followed by flow through the fractures. If the release of gas from the matrix to the cleats is very rapid compared to the flow of gas and water in the cleats, the desorption kinetics are relatively unimportant in modelling coal-bed methane production. This assumption allows the adsorption of gas on the surface of the coal to be modeled as gas dissolved in an immobile oil. The solution gas-oil ratio of this immobile oil is calculated from the Langmuir adsorption isotherm curve. A conventional reservoir simulator can be used to describe coal-bed methane. No source code modification is required. Based on the thoughts above, this paper simulates coal-bed methane production using conventional thermal model, and the trend is very close compared with the results calculated by coal-bed methane simulation software(COMETPC).