煤层气渗流规律与压力特征分析

Analysis on Flow through Porous Media and Pressure Characteristics of Coalbed Methane

本文采用非平衡态吸附模型,研究单相煤层气在煤体和割理中的流动规律。在拟稳态流和不稳态流的数学模型假设下,用气体拟压力代替Langmuir吸附公式中的压力,得到气层中拟压力所满足的方程,并对渗透率变异系数和双重介质参数变化时压力的变化规律进行了分析。这些结果为煤层气藏开发提供了理论依据和新的试井模型。

There are two processes of dispersion and seepage when extracting CBM and its seepage process is more compheatod than that in strata with regular natural gas. The study on the flow law of single- phase CBM in coal body and cleat has been made with the absorbing model in non- equivalent state. Under the assumption of mathematical model in the imitative stable flow and unstable flow, the pressure in the Langrnuir Absorbing Formula is replaced with imitative gas pressure that has led to the equation with satisfied imitative pressure in the CBM strata. Analysis is also made on variable coeglcients of permeabihty and the changing law of pressure with changes of parameters in double media. All these results have provided both the theory basis and new model for pilot wells to develop CBM resources.