一种三维正交方位各向异性介质岩石物理建模及弹性波正演模拟方法

Rock physics modeling and elastic wave forward modeling methods in a three-dimensional azimuthally anisotropic medium of orthorhombic symmetry

通过线性滑动理论和岩石物理等效理论,将两组正交直立裂隙介质等效为一种正交方位各向异性介质进行三维岩石物理建模,通过高阶交错网格有限差分求解弹性波动方程模拟地震波在该种介质中的传播过程.在建模过程中改变物性参数,分析不同裂隙密度条件下的炮集和波场特征,以及正交各向异性的方位特征.研究结果表明,各向异性强度随裂隙密度等物性增大而增强,而且这些特征在共炮点道集和波场中均有所体现.

In this paper,by rock physical equivalent theory and linear slip theo-ry,two sets of orthorhombic fractures are equivalent to a new three-dimensional azimuthally anisotropic medium of orthorhombic symmetry for rock physical modeling.And then elastic wave equations are solved to simulate the propaga-tion process in this medium by high-order staggered-grid finite-difference method.During the process of modeling,with the variation of physical parame-ters,we analyze CSP （common shot points）sets and the wave field characteris-tics on the conditions of different fracture densities,as well as azimuthal charac-teristics of orthorhombic anisotropy.The research results show that the aniso-tropic strengths enhance with fracture density increasing,which is reflected in the CSP sets and forwarding wavefield.