考虑微裂缝的页岩气藏三重介质不稳定产量递减研究

The Research about Transient Production Decline of Triple Porosity Model Considering Micro Fractures in Shale Gas Reservoir

据观测,用传统模型得到的页岩气生产数据要远低于现场数据;而为了达到拟合的目的,要人为修改缺乏物理依据支撑的储层参数。为了达到提高裂缝性页岩气藏产能模拟能力的目的,需要对页岩气的流动规律及产能进行研究。通过结合页岩气藏特征扩展双重介质模型的非稳态方程,在双重介质模型的基础上加入微裂缝作为沟通基质与人工裂缝网络的通道;并利用Langmuir等温吸附方程描述页岩气的吸附现象,建立了一个新的三重介质模型。分析了窜流系数、Langmuir体积和Langmuir压力对页岩气井不稳定产量的影响,对比了新模型与传统双重介质模型所预测的产量。

It was observed that the actually field data of shale gas production is much higher than that modeled with conventional models,so that the reservoir parameter （without much physical support） needed be changed for well matching.For the objective of improving the productivity simulating capability of shale gas reservoir,it is essential to research on seepage mechanism and productivity of shale gas.Unlike conventional gas reservoir,the shale gas reservoir has the adsorption and desorption characteristics.Combined with Langmuir isotherm equation,the reservoir properties and micro fractures,the transient equations of dual porosity model are extended to a new triple porosity model.Additionally,the effect of interporosity flow coefficient,Langmuir volume and Langmuir pressure on shale gas wells production is analyzed and the predicted production of new model with that of conventional model is compared.