Characteristics of wave propagation in anisotropic two-phase media
Liu Xinxin1, Yin Xingyao1, Zhang Feng2, Zhang Xiuqi3
1. School of Geosciences, China University of Petroleum (East China), Qingdao, Shandong 266580, China;
2. College of Geophysics and Information Engineering, China University of Petroleum (Beijing), Beijing 102249, China;
3. BGP Inc., CNPC, Zhuozhou, Hebei 072751, China
Abstract：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.
