摘要
以波动理论为基础的表层波场校正与叠前深度偏移技术是提高山前带复杂构造成像精度的有效手段。本文介绍了基于广角隐式有限差分单程波传播算子的起伏地表叠前深度偏移方法,并对SEG山前带推覆构造模型进行了检验。结果表明:起伏地表波动方程叠前深度偏移照明加权成像结果与理论模型构造形态非常吻合。在此基础上,将此法用于玉门油田窟窿山模型合成数据体,分别进行了静校正与波动方程基准面延拓、叠后深度偏移与叠前深度偏移、Kirchhoff偏移与波动方程偏移的处理结果对比,得出了如下结论:①在地表起伏剧烈、表层速度横向变化大、高速地层直接出露地区,常规时移静校正误差远远大于波动方程基准面校正的误差;②在波动方程基准面校正的基础上,波动方程叠前深度偏移的精度明显高于Kirchhoff偏移法的精度;③起伏地表波动方程叠前深度一步法偏移还能合理地描述地表附近反射面的形态。
Surface layer wave field correction taking wave theory as basis and prestack depth migration are effective means for improving imaging precision of piedmont complex structures. The paper introduced the prestack depth migration from relief surface based on implicit wide-angle finite-difference one-way propagation operator and used SEG piedmont nappe structure model for test. The result showed that the illuminated weighting imaging results by wave equation prestack depth migration from relief surface very coincide with the structural configuration of model. On that basis, using this method for synthetic data volume of Kulongshan model in Yumen Oilfield and carrying out the correlation among the following processed results: static correction and wave equation datuming continuation, poststack depth migration and prestack depth migration, Kirchhoff migration and wave equation migration, which concluded as follows: in the area of strong relief surface, large lateral variation of surface velocities and directly emerging high-velocity beds, the error of common time-shift static correction is far greater than that of wave equation datuming correction; ②on the basis of wave equation datuming correction, the precision of wave equation prestack depth migration is distinctively higher than that of Kirchhoff migration; ③one-step method of wave equation prestack depth migration from relief surface can also reasonably describe the configuration of reflectors near surface.
出处
《石油地球物理勘探》
EI
CSCD
北大核心
2006年第5期525-529,共5页
Oil Geophysical Prospecting
关键词
山前带
起伏地表
静校正
波动方程基准面延拓
叠前深度偏移
piedmont zone, relief surface, static correction, wave equation datuming continuation, prestack depth migration
