基于裂缝等效模型的波动方程正演模拟

Wave Equation Forward Modeling Based on Fracture Equivalent Model

为了解决裂缝介质波动方程正演模拟时,裂缝介质的建模问题,针对高角度的裂缝介质(可视为HTI介质),通过Thomsen等效模型建立裂缝介质模型,采用交错网格有限差分法对三维HTI介质弹性波动方程进行求解,模拟地震波在裂缝介质中的传播过程。用AVAZ(Amplitude versus Azimuth)对正演模拟合成的地震记录进行裂缝属性参数反演,反演结果与模型真实值基本一致,表明了Thomsen等效模型结合裂缝密度建模的正确性和有效性。通过结合Thomsen裂缝等效模型以及各向异性参数δ,ε,γ与裂缝密度的关系,使得在HTI介质波动方程正演时,裂缝模型的建立更加简单、方便简洁。

In order to solve the modeling problem of fracture medium in forward simulation of wave equation of fracture medium,this paper adopts the Thomsen equivalent model to build the fracture medium model and the staggered-grid finite differential method(SFDM)to solve the elastic wave equation of three-dimensional HTI media,and simulates the propagation process of the seismic wave.The AVAZ(Amplitude versus Azimuth)is used to invert the fracture parameters for synthetic seismic data.The inversion results are basically consistent with the true fracture parameters of the model,which shows the correctness and effectiveness of the Thomsen equivalent model and fracture density model.By combining the Thomsen fracture equivalent model and the relationship between the anisotropic parametersδ,ε,γand the fracture density,the establishment of the fracture model is simpler,more convenient in the forward modeling of the HTI medium wave equation.