基于改进BISQ机制的双相HTI介质波传播伪谱法模拟与特征分析  

Pseudo-spectral modeling and feature analysis of wave propagation in two-phase HTI medium based on reformulated BISQ mechanism

作　　者：刘财[1] 兰慧田[1] 郭智奇[1] 冯晅[1] 鹿琪[1] 

机构地区：[1]吉林大学地球探测科学与技术学院,长春130026

出　　处：《地球物理学报》2013年第10期3461-3473,共13页Chinese Journal of Geophysics

基　　金：国家自然科学基金项目(40974054);国家重点基础研究发展计划(973)项目(2009CB219301);油页岩勘探开发利用产学研用合作创新研究项目(OSP-02;OSR-02)联合资助

摘　　要：改进BISQ(Biot-Squirt)机制在不引入特征喷流长度的情况下,将含流体孔隙介质中Biot流动和喷射流动两种重要的力学机制有机地结合起来,且各相关参数具有明确物理意义和可实现性.本文将改进BISQ机制一维孔隙流体压力公式推广到三维具有水平对称轴横向各向同性介质(HTI介质)情况,结合裂缝各向异性理论,给出了基于改进BISQ机制的双相HTI介质模型及其二维三分量波传播方程,采用伪谱法求解该方程,进行了不同相界、不同频率以及双层地质结构情况下该类介质中波场的数值模拟与特征分析.数值模拟结果表明:伪谱法模拟精度高,压制网格频散效果好,可以得到高精度的波场快照和合成记录;基于改进BISQ机制的双相HTI介质模型兼具裂缝各向异性特征和孔隙弹性特征,其为从双相各向异性理论角度深入研究裂缝性储层的地震响应奠定了理论基础.In the case without introducing characteristic squirt flow length, the reformulated BISQ mechanism combines the Biot and squirt-flow mechanism which are two important fluid flow styles in the porous media with fluid, and the relative parameters have a clear physical meaning and can be obtained or estimated from independent measurements. In this paper, the expressions of pore fluid pressure is extended to three-dimensional transversely isotropic medium with a horizontal symmetry axis （HTI medium） from one-dimensional case, combining fractured anisotropic theory, the two-phase HTI medium model based on reformulated BISQ mechanism and two-dimensional, three-component wave equations are presented. Following the equations, elastic wavefield in this medium model is simulated by the pseudo-spectral method for different frequency and phase boundary and two-layer medium cases, and then the wavefield features are analyzed. The results of numerical modeling indicate that the pseudo-spectral algorithm have highprecision and can suppress effectively grid numerical dispersion, and high-precision wavefield snapshots and synthetic seismograms can be obtained. The two-phase HTI medium model based on reformulated BISQ mechanism has the characteristics of fractured anisotropic and poroelastic medium, which will lay a foundation of further studies on seismic responses of fractured reservoir from the standpoint of two-phase anisotropic theory.

关 键 词：改进BISQ机制 双相介质 裂缝各向异性 伪谱法 波场特征 

分 类 号：P631[天文地球—地质矿产勘探]