摘要
针对TTI介质交错网格高阶有限差分正演模拟精度低及矢量波型分离不彻底的问题,发展了一种TTI介质Lebedev网格高阶有限差分正演模拟方法及矢量波型分离一体化处理流程。首先从一阶偏导数弹性波速度—应力方程出发,构建了TTI介质Lebedev网格高阶差分波场递推格式;然后借助Low-rank分解策略处理由极化矢量构成的空间—波数域分离算子,进而对速度分量实施纵、横波型分离;最终实现了Lebedev网格高阶差分方案与纵、横波分离模拟思路的有机结合,形成了复杂TTI介质高精度正演模拟与波型分离一体化处理流程。在实现方法的基础上,对均匀介质、层状介质以及复杂BP2007模型进行了正演及分离测试。计算结果表明:选取Lebedev网格高阶有限差分能够减小交错网格剖分方式带来的插值误差,从而获得高精度矢量波场;其次,通过应用Low-rank分解波型分离方法能够实现矢量波彻底分离,得到完全解耦的纵、横波场;文中方法对非均匀复杂模型具有良好的适应能力。
Since conventional staggered grid high-order finite-difference shows low accuracy for forward modeling in TTI media,and elastic wave-mode separation in heterogeneous TTI media is incomplete,we develop an integrated processing workflow of modeling with Lebedev grid high-order finitedifference scheme and elastic wave-mode separation.First,based on the first-order partial derivative elastic wave velocity-stress equations,the TTImedium Lebedev grid high-order finite-difference recurrence formula is constructed.Then low-rank decomposition algorithm is employed to solve space-wavenumber domain separation operator composed of polarized vectors.Finally the operator is used to separate compressional wave or shear wave from velocity components.Thus we achieve the perfect combination of Lebedev grid high-order finite-difference scheme with compressional and shear wave separation,and build an integrated processing workflow of modeling with Lebedev grid high-order finite-difference scheme and elastic wave-mode separation for TTI media.Numerical tests on homogeneous model,layered model and complex BP2007 model demonstrate three advantages of our proposed approach:(1)Our proposed approach produces high-precision vector wave fields because the interpolation error related to staggered grid strategy can be significantly eliminated by selecting Lebedev grid finite-difference scheme;(2)Our proposed approach completely separates elastic wave fields and obtain decoupled qP-and qSVwaves using low-rank decomposition algorithm;(3)the proposed approach shows strong adaptability to complex heterogeneous medium.
出处
《石油地球物理勘探》
EI
CSCD
北大核心
2017年第5期915-927,共13页
Oil Geophysical Prospecting
基金
国家重点基础研究发展计划项目(2014CB239006)
国家自然基金项目(41274124)
中央高校科研业务费专项基金项目(R1401005A)
中国石油大学(华东)研究生创新工程资助项目(YCXJ2016005)联合资助
