页岩气开采中的压力变化与气液传质规律

PRESSURE CHANGE AND GAS-LIQUID MASS TRANSFER LAWS IN SHALE GAS EXTRACTION

  • 摘要: 根据页岩气的赋存及流动机理,建立考虑页岩渗吸与吸附、渗流与扩散的流动方程,采用线段源叠加解等效为压裂产生的压力分布作为方程的初始条件,使用非结构PEBI(perpendicular bisection)网格对水平井多段压裂井进行网格划分,有限体积法进行离散。利用高频压力监测的闷井压力数据验证了算法程序的可靠性。研究得出以下结果:(1)发现页岩气开发的压力双漏斗及气液双向传质流动规律;(2)依据这一规律给出页岩气压最佳闷井时间和最优排采制度。

     

    Abstract: Based on the occurrence and flow mechanism of shale gas, this article establishes a flow equation that considers shale infiltration and adsorption, as well as seepage and diffusion. The pressure distribution generated by fracturing is used as the initial condition of the equation using line source superposition solution. Unstructured perpendicular bisection (PEBI) grids are used to divide the multi-fractured horizontal wells, and the finite volume method is used for discretization. The reliability of the algorithm program was verified by using the shut-in pressure by high-frequency pressure monitoring. The study has drawn important conclusions: (1) discovering the double pressure funnel and gas-liquid two-way mass transfer laws in shale gas development; (2) Based on this theory, provide the optimal shut- in time and optimal drainage system for shale gas production.

     

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