流体饱和正交裂缝孔隙型介质数值模拟及波场特征分析  

Numerical simulation and wavefield characteristics analysis of fluid-saturated porous medium with orthogonal fractures

作　　者：王钰鹏 李小斌 阎建国[1] WANG Yupeng;LI Xiaobin;YAN Jianguo(College of Geophysics, Chengdu University of Technology,Chengdu 610059, China)

机构地区：[1]成都理工大学地球物理学院,成都610059

出　　处：《物探化探计算技术》2021年第6期697-704,共8页Computing Techniques For Geophysical and Geochemical Exploration

基　　金：国家油气重大专项(2016ZX05046-006)。

摘　　要：裂缝型油气藏作为非常规油气藏,勘探开发都极具挑战,研究裂缝作用下的地震波传播特征有着重要的意义。这里通过线性滑动理论来表征两套相互垂直的裂缝系统,然后引入孔隙,结合各向异性Gassmann方程,使得孔隙和裂隙液压连通,构建流体饱和裂缝孔隙性介质。通过Biot理论建立了饱和正交裂缝孔隙型介质的一阶速度应力方程,使用高阶有限差分方法对介质进行数值模拟,分析其裂缝参数对波场特征的影响。结果表明,慢qP波形态不随裂缝参数变化,法向弱度变化对快qP波影响大,切向弱度的变化对qSV波影响大,对于快qP波而言,主要是影响除裂缝切向和法向以外的速度。As a type of unconventional hydrocarbon reservoir,fractured reservoirs are extremely challenging for us to explore,so it is of great significance to research the propagation characteristics of seismic waves in the fractured medium.The linear sliding theory can be used to characterize two sets of fracture systems that are perpendicular to each other.Combined with anisotropic Gassmann equation,we introduce pores and establish the fluid-saturated porous medium with orthogonal fractures.The study uses the first-order velocity stress equation of Biot theory and the finite-difference method to simulate seismic waves'propagation in the medium we build.The results show that the shape of the slow qP wave does not change with the fracture parameters.The change of normal weakness has a great influence on fast qP waves,and the change of sheer weakness has a great influence on qSV waves.For fast qP waves,it mainly affects the velocity between fractures tangential direction and normal direction.

关 键 词：BIOT理论 线性滑动理论 GASSMANN方程 正交裂缝 数值模拟 

分 类 号：P631.4[天文地球—地质矿产勘探]