【摘要】 研究井间地震波场的形成过程以及波场的传播机理、规律,对于指导实际井间地震勘探有着重要的意义。基于具有垂直对称轴的横向各向同性(VTI)介质中的一阶准P波方程,应用具有无条件稳定性质的紧致交错网格隐式差分格式求解该方程。重点研究了紧致交错网格求解该方程的完全匹配层(PML)吸收边界条件,在此基础上实现了VTI介质中一阶准P波方程的井间地震波场的正演模拟。数值算例表明:紧致交错网格能精准模拟VTI介质中准P波的传播过程,得到高精度的正演结果。一阶准P波方程能以足够的精度描述VTI介质中准P波特征。完全匹配层吸收边界能有效地解决人工边界问题,是一种高效的边界吸收算法。更多还原

【Abstract】 Study on the build-up process and the spreading mechanism of cross-hole seismic wave field is very important for guiding actual cross well seismic exploration.Based on the first-order quasi-P wave equation in transversely isotropic media with a vertical symmetry axis(VTI),the finite difference scheme of the equation which was solved in the compact staggered grid was constructed.The compact staggered grid is implicit difference scheme which has the characteristic of unconditional stability.The perfectly matched layer(PML) absorbing boundary condition which fit the equation were thoroughly studied.Based on the studies above the forward modeling was realized for the first-order quasi-P wave equation in VTI medium.In summary,compact staggered-grid finite difference scheme could have a high degree of accuracy to simulate the spreading process of quasi-P wave in VTI medium.The first-order quasi-P wave equation could describe the characteristic of quasi-P wave in VTI medium with a high accuracy.PML is one of the best absorption boundary conditions which can effectively deal with the problem of article boundary.更多还原