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在地震资料处理中,为提高地下地质体成像精度,各向异性叠前偏移已逐渐成为常规处理流程.然而,如何可靠地估算和建立各向异性深度偏移的各向异性参数模型是其成功的关键.针对K油田浅层气和边界大断层对地震成像的不利影响,采用了沿层速度分析和网格层析相接合的速度建模方法、利用已知井的信息求取初始各向异性参数、并通过多次迭代更新各向异性参数和速度模型等方法和处理流程,对K油田三维地震资料进行了各向异性叠前深度偏移处理.与只依靠单一速度参数的各向同性叠前深度偏移相比,各向异性叠前深度偏移利用了地震波垂直传播的相速度和根据井控从地震数据中估算出来的两个各向异性参数.从偏移结果中可以看到,各向异性叠前偏移的成像精度和质量得到明显改善,目的层地震偏移深度与井上分层深度吻合更好,地层信息与测井结果一致性好,边界断层的归位更加准确.
In seismic data processing, anisotropic prestack migration has gradually become a routine process in order to improve the imaging accuracy of underground geological bodies.However, how to reliably estimate and establish an anisotropic anisotropic parameter model of anisotropy is its The key to success.Aiming at the unfavorable effects of shallow gas and boundary faults on seismic imaging in K oilfield, a velocity modeling method based on layer velocity analysis and mesh-phase tomography is used to calculate the initial Anisotropic parameters and anisotropic prestack depth migration of anisotropic prestack seismic data in K oilfield are carried out by iteratively updating anisotropic parameters and velocity models, The anisotropy of prestack depth migration utilizes the phase velocity of vertical seismic wave propagation and the two anisotropy parameters estimated from seismic data based on well control as compared to the same-sex prestack depth migration. As can be seen from the offset results The imaging accuracy and quality of anisotropic prestack migration have been significantly improved. The depth of seismic migration in target layer agrees well with the depth of uphole stratification. The formation information is consistent with the logging data Well, homing boundary faults more accurately.