基于树状分形网络的裂缝性气藏试井模型

A Model of Wells Testing in Fractured Gas Reservoirs Based on Tree Fractal Network

张本健 曹建 邓清源 李旭成 王宇峰

ZHANGBenjian CAOJian DENGQingyuan LIXucheng WANGYufeng

西南石油大学地球科学与技术学院, 四川 成都 610500 中国石油西南油气田分公司川西北气矿, 四川 江油 621700

School of Geoscience and Technology, Southwest Petroleum University, Chengdu, Sichuan 610500, China Sichuan Northwest Gas Mine of Southwest Oil and Gas Field Branch, PetroChina, Jiangyou, Sichuan 621700, China

针对裂缝性气藏试井渗流问题，基于树状分形网络对径向流动模拟的优越性，使用树状分形网络模拟气藏裂缝系统，并将树状分形网络嵌入到气藏中，提出了基于树状分形网络的裂缝性气藏试井模型，计算出试井模型的流动动态特征典型曲线，分析了长度比、直径比、分叉角度、总分叉级数和分叉级数对拟压力动态特征的影响，长度比、分叉角度和分叉级数主要影响动态特征典型曲线中基质系统向裂缝系统窜流阶段，总分叉级数主要影响总系统径向流阶段，直径比影响除井筒储集阶段外的所有阶段。结果表明，树状分形网络能够很好地模拟裂缝性气藏的渗流特征。

To resolve the seepage issue in testing wells in fractured gas reservoirs, we simulated the fractured gas reservoir system using the tree fractal system, considering the superiority of this method in simulating radial flow. The tree fractal network is embedded in the gas reservoir and a model of a testing well in a fractured gas reservoir is proposed based on the tree fractal network. Furthermore, we calculated the characteristic curves of flow dynamics in the testing well model and analyzed the effect of length ratio, diameter ratio, bifurcation angle, total number of bifurcations, and number of bifurcations on the dynamic characteristics of pseudo-pressure. The length ratio, bifurcation angle, and number of bifurcations have a major influence on the particular part of dynamic characteristic curve where the fluid from the matrix system flows to the fracture system; the total number of bifurcations primarily affects the radial flow in the entire system; and the diameter ratio has a major impact on all stages, except for the storage stage in the wellbore. The results demonstrate that the tree fractal network can provide satisfactory simulation of the seepage characteristics of fractured gas reservoirs.

10.11885/j.issn.1674-5086.2018.03.22.01