双相各向异性介质地震波传播特征

实际裂隙性油气储层表现出双相各向异性特征。本文基于岩石物理理论求取裂隙介质各向异性等效弹性参数，结合各向异性BISQ理论，建立了裂隙诱导双相各向异性介质理论模型。从双相各向异性介质的弹性波方程出发，推导出平面波的Christoffel方程，求解该方程获得了三维双相完全各向异性介质中qP1、qP2、qSV和qSH波的波数方程，据此波数方程计算四类波的相速度和衰减因子。最后针对碎屑岩水平裂隙诱导双相各向异性介质，分析了泥质含量、裂隙密度和形状、孔隙度、含水饱和度、流体黏滞系数、渗透率等参数对弹性波沿不同方向传播时相速度和能量衰减特征的影响，可为储层的孔隙、裂隙结构及含油气性等分析提供理论依据。

Characteristics of wave propagation in anisotropic two-phase media

Fractured hydrocarbon reservoirs show anisotropic and two-phase characteristics. To reasonably describe the propagation of seismic waves in this kind of media, the equivalent anisotropic parameters are calculated based on rock physics theory; and then the anisotropic two-phase theoretical model is established combined with anisotropic BISQ theory. From the elastic wave propagation equations, the Christoffel equation of plane wave is derived. The wave-number equation for qP₁, qP₂, qSV and qSH waves in 3D totally anisotropic two-phase elastic media are obtained by solving this equation. Then the phase velocity and attenuation factors of these kinds of waves can be calculated. Finally, for the two-phase media of clastic reservoir with anisotropy induced by horizontal fractures, the changes of wave phase velocities and attenuation factors with clay content, crack density and shape, porosity, water saturation, viscosity, permeability and different propagation azimuth are analyzed, which can provide theoretical support for the pore and fracture structure analysis and for the prediction of oil or gas-bearing reservoirs.