综合运用渗流力学、数学物理方法、计算数学基础理论,基于严格的数学推导,建立裂缝性气藏分支水平井不稳定试井模型,并求得模型的 Laplace 空间解,利用 Stehfest 数值反演结合计算机编程,绘制出裂缝性气藏鱼骨型分支水平井的典型曲线。结果表明:裂缝性气藏鱼骨型分支水平井不稳定渗流过程可能出现早期纯井储段、井储后过渡段、裂缝系统第一径向流段、裂缝系统线性流阶段、裂缝系统第二拟径向流段、分支干扰过渡段、裂缝系统第三拟径向流阶段、窜流段和总系统拟径向流段9个流动阶段;水平井分支长度越短或分支间距越长,第二拟径向流段越明显。
A well testing model for multilateral horizontal wells in naturally fractured gas reservoirs was established based on the theory of fluid flow in porous media, and its analytical solution in Laplace domains was obtained. The characteristic curves for flows in commonly applied fishbone-type wells were plotted using a Stehfest numerical inversion algorithm. Nine different flow re-gimes can be identified and classified from the characteristic curves, including an early pure wellbore flow, a transitional flow, the first radial flow of the natural fracture system, a linear flow of the natural fracture system, the second pseudo-radial flow of the nat-ural fracture system, an interference flow between the multiple well branches, the third pseudo-radial flow of the natural fracture system, an inter-porosity flow and a compound pseudo-radial flow. A parametric analysis shows that the shorter the fishbone-type branches or the longer the interspacing, the longer the duration of the second pseudo-radial flow.