页岩多重介质模型与页岩气井压力动态分析

Multi-Porosity Medium Model for Gas Shale and Pressure Performance Analysis of Shale Gas Well

有机孔和无机孔中气体赋存方式的差异性决定二者中赋存气体释放方式不同,即考虑吸附气的常规双重介质拟稳态或不稳态窜流模型难以有效体现页岩基质中气体的传质过程。结合页岩气的赋存方式和有机孔与无机孔含量的差异性,将页岩基质中气体传质模型分为双重介质模型、双渗介质模型和三重介质模型,以双渗介质模型为例,建立相应的物理模型和数学模型,绘制典型曲线,分析参数敏感性,为认识页岩中气体传质过程对页岩气井压力动态的影响提供帮助。

The difference of gas storage mode between organic-pores and inorganic-pores can be observed in selecting the description method of gas migration in shale matrix,namely,the conventional dual-porosity pseudo-steady inter-porosity flow model or unsteady inter-porosity flow model is difficult to describe the gas migration process in shale matrix. Combining different gas storage mode in shale,gas migration in shale,gas reservoir can be divided into dual-porosity medium model,dual-permeable medium model and triple-porosity medium model. Then taking the dual-permeable medium model as an example,the corresponding physical model and mathematical model are established,type curves of pressure responses are plotted,and the sensitivity analysis of relative parameters are carried out. And this work is helpful to understand the influence of gas migration in gas shale on the pressure dynamics of shale gas well.