气藏压裂水平井非稳态流动分析

Analysis of transient flowing model for fractured horizontal well in gas reservoir

应用Green函数和Newman积原理,建立了压裂水平井与气藏耦合的非稳态流动模型,并给出求解方法。所建立的模型可应用多种约束条件,考虑了井筒压降和加速度的影响,并适用于各向异性气藏。实例计算表明:水平井在早期非稳态阶段的流量比拟稳态阶段大得多。早期非稳态流动阶段,各条裂缝之间未发生干扰,流量的大小与裂缝条数成正比例关系。受摩阻和加速度压降的影响,跟端裂缝的产量明显大于其他位置裂缝的产量,越靠近指端,裂缝的流量越小。

Based on Green function and Neumann product principle,a flow model of fractured horizontal well coupled with gas reservoir under unsteady state is established and the method to solve this problem is also given.The established model is available for anisotropic gas reservoir in consideration of pressure drop along the wellbore caused by friction and acceleration,making use of various constraints.Calculation results show that,flow rate of horizontal well under early unsteady state is larger than that under pseudo-steady state.There is no interference among fractures in early unsteady state,and flow rate is in direct proportion to fracture numbers.Flow rate of end fractures is obviously larger than that of other fractures,affected by frictional and accelerational pressure drop.The closer fractures are to the toe,the smaller the flow rate of fractures is.