页岩气渗流机制数学表征及Knudsen扩散影响分析

Mathematical Characterization of Seepage Flow Mechanisms and Influence of Knudsen Diffusion in Shale Gas Reservoir

基于双重介质,建立基质和裂缝的运动方程。考虑基质和裂缝的黏性流及Knudsen扩散作用,采用Langmuir等温吸附方程表征气体分子在基质孔隙的吸附与解吸附作用。同时,通过Knudsen扩散的质量流量公式,分析孔隙半径、压力和温度变化对质量流量的影响。

Based on dual porosity medium,the kinematic equations of matrix and fracture are built.Viscosity flow,Knudsen diffusion and gas adsorption-diffusion in pore have been considered in matrix.Langmuir isothermal adsorption equation is also used to characterize adsorption and desorption of gas molecules in matrix pores.Meanwhile,the influence of pore radius,pressure and temperature on mass flow is studied through mass flow rate formula of Knudsen diffusion.