页岩气藏三重介质模型压力动态分析及其应用

Pressure dynamic analysis and application of triple medium model for shale gas reservoir

封钦亚 许艺博 张欣 刘静华 杜春雨 田玉明

 中国石油大学（北京）国家重点实验室，北京 102249

 State Key Laboratory of Petroleum Engineering, China University of Petroleum, Beijing 102249, China

 不同于常规气藏，页岩气藏储层及页岩气的储存、运移都具有十分复杂的特性，其气体渗流过程描述也相当困难。为了解页岩气储层气体的流动规律、井底压力动态及影响因素，进而有效地开发页岩气，文中对页岩气藏渗流规律进行了研究，并基于双重介质模型，建立了新的三重介质模型。新模型考虑了页岩气吸附机理，假设基质为双重孔隙介质，且带有微裂缝，微基质和裂缝之间有气体流动；对方程进行了离散化差分，通过Matlab编程进行求解，讨论了3个系统的窜流系数、弹性储容比，以及裂缝与基质渗透率比对井底压力的影响；最后通过对比现场实际数据，使建立的模型得到有效验证。

 Unlike conventional gas reservoir, shale gas reservoir, migration and storage process are very complicated and particular, which lead to the complexity of seepage process description. In order to obtain a better understanding of shale gas flow rule, the dynamic of bottom pressure of shale gas well and influencing factors to develop shale gas efficiently, the seepage law is researched and a triple medium model is built. The new model is based on shale gas adsorption mechanism, assuming the matrix blocks a dual porosity media with micro fractures, and gas flow between sub-matrix and fractures. Using discretization difference, the equation is solved by the matlab programming, the cross flow coefficient of three systems, storativity-ratio and the effect of permeability ratio of fracture to matrix on pressure are discussed, finally the model is validated by in situ data.

10.6056/dkyqt201505012