煤层气排采储层压降传播规律研究

Study on Pressure Drop Transmission Law of Coal Bed Methane Drainage Reservoir Stratum

根据煤层中的渗流机理建立了煤层压力分布数学模型,计算出煤层气排采时煤层中的压力分布情况,揭示煤层中压降传播的规律。利用Matlab7.11软件模拟晋城某区块煤层气储层压降传播情况,分析了影响压降速度、压降大小以及压降传播距离的因素。研究表明:煤层的渗透率、孔隙度、压缩系数及排采时间对煤层中各点的压降速度影响较大;煤层压降与产水量、煤层有效厚度、煤层的渗透率、孔隙度、排采时间和煤层含水量呈正相关;煤层的渗透率、孔隙度、排采时间与压降在煤层中传播的距离呈正相关。

Based on the seepage mechanism in seam, a mathematical model of the seam pressure distribution was established, the pres- sure distribution conditions of the seam during the gas drainage process were calculated and the pressure drop transmission law of the seam was revealed. The Matlah7.11 was applied to simulate the coal bed methane reservoir stratum pressure drop transmission conditions of a mining block in Jincheng Mining Area and analyze the factors affected to the pressure drop speed, the pressure drop size and the pressure drop transmission distance. The study showed the seam permeability, porosity and compression coefficient as well as the water drainage time would have high influences to the pressure drop speed at each point in the seam. The pressure drop would he positively related to the water drainage value, effective thickness of the seam, permeable rate of the seam, porosity, gas drainage time and water content of seam. The seam permeable rate, porosity and gas drainage time would be positively related to the pressure drop transmission distance in seam.