应力敏感页岩气藏压力动态分析

Pressure Dynamic Analysis of Stress-Sensitive Shale Gas Reservoir

摘要: 本文在Langmuir等温吸附理论的基础上，建立了考虑应力敏感作用的裂缝性页岩气藏在不同边界条件下的双重介质渗流数学模型。考虑到模型存在很强的非线性，在求解过程中将解吸作用考虑成基质等温压缩系数的增加，降低了模型的非线性程度。通过Laplace变换、摄动变换最终得到了数学模型在Laplace空间的解析解，最后通过编程绘制了压力动态曲线，分析了压力动态曲线的特征，并对影响压力动态曲线的因素进行了参数敏感性分析，研究结果可为页岩气藏的试井分析提供科学依据。

Abstract: Based on the theory of Langmuir isothermal adsorption, the mathematical model of double media seepage in fractured shale gas reservoirs which considers stress sensitivity under different boundary conditions is established in this paper. Taking the strong nonlinearity of the model into account, desorption effect can be considered as the increase of isothermal compressibility of matrix during the resolution to decrease the degree of nonlinearity of the model. The analytical solution of the mathematical model in Laplace space is obtained by means of Laplace transformation and perturbation transformation. Finally, pressure transient curves are drawn with the aid of computer programs, and its characteristics have been analyzed, and parameter sensitivity analysis for the contributing factors affecting the dynamic curve of pressure also has been done. The results can provide scientific basis for well test analysis of shale gas reservoirs.