不同介质模型的双聚焦计算方法
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摘要
双聚焦计算方法模拟了两个三维波场响应过程:一是三维波场正演过程;二是三维波场叠前偏移过程,因此双聚焦算法的关键在于波场外推。不同介质模型采用不同的波场外推方法:直接外推法适用于最简单的均匀介质模型;大步长逐层递推法适用于层状均匀介质模型;小步长三维网格递推法适用于复杂介质模型。实际应用表明:针对复杂地质目标的双聚焦成像空间分辨率和照明强度预测,对于优化三维观测系统设计和提高地震成像质量具有重要作用。考虑到三维正、反向波场递推的计算量极大,建议在多节点的并行机上进行复杂介质双聚焦方法的软件开发。
Double-focus algorithm simulates two processes of 3-D wavefield response: one is forward process of 3-D wavefield, the other is the process of prestack migration of 3-D wavefield, so that the key of double-focus algorithm is extrapolation of wavefield. Different extrapolation methods are used for the models in different media: the direct extrapolation is suitable for the model in the simplest homogeneous model; the recursive method layer by layer in large step is suitable for the model in layered homogeneous medium; the 3-D grid recursive method in small step is suitable for the model in complex medium. The practical application showed that the prediction of double-focus imaging spatial resolution and illuminating power for complex geologic targets plays an important role in optimum design of 3-D geometry and in improvement of seismic imaging quality. Considering a great mount of computational efforts in forward and inversive recursive computation of 3-D wave-field, we suggest that software development of double-focus algorithm in complex media should be carried out in parallel computer with multiple nodes.
Double-focus algorithm simulates two processes of 3-D wavefield response: one is forward process of 3-D wavefield, the other is the process of prestack migration of 3-D wavefield, so that the key of double-focus algorithm is extrapolation of wavefield. Different extrapolation methods are used for the models in different media: the direct extrapolation is suitable for the model in the simplest homogeneous model; the recursive method layer by layer in large step is suitable for the model in layered homogeneous medium; the 3-D grid recursive method in small step is suitable for the model in complex medium. The practical application showed that the prediction of double-focus imaging spatial resolution and illuminating power for complex geologic targets plays an important role in optimum design of 3-D geometry and in improvement of seismic imaging quality. Considering a great mount of computational efforts in forward and inversive recursive computation of 3-D wave-field, we suggest that software development of double-focus algorithm in complex media should be carried out in parallel computer with multiple nodes.
引文
[1] Berkhout A J and Ongkiechong L. Analysis of seismic acquisition geometries by focal beams. SEG Expanded Abstracts,1998
[2] Volker A W E et al. Analysis and optimization of 3-D seismic acquisition geometries by focal beams. SEG Expanded Abstracts, 2000
[3] Berkhout A J et al. Comprehensive assessment of seismic acquisition geometries by focal beams-Part I: Theoretical consideration. Geophysics, 2001,66(3): 911-917
[4] Volker A W E et al. Comprehensive assessment of seismic acquisition geometries by focal beams-Part II: Practical aspects and examples. Geophysics, 2001,66 (3):918~931
[5]别尔克豪特A J著;马在田等译．地震偏移——波场 外推法声波成像．北京:石油工业出版社,1983
[6]狄帮让等．三维观测系统优化设计的双聚焦方法．石 油地球物理勘探,2003,38(5):463～469
[7] Cao Wei-ping et al. Migration spatial resolution esti mation algorithm for stratified medium with focal beams. SEG Expanded Abstracts .2003
[8]倪成洲等．层状介质双聚焦方法优化观测系统设计软 件的开发．石油地球物理勘探,2004,东部会议专刊:5 ～8
[9] Veldhuizen E J et al. Acquisition geometry analysis u-sing quantitative measures for image quality. SEG Expanded Abstracts ,2003
[10]狄帮让等．孔径角对三维波场外推精度的影响．石油 地球物理勘探,2005,40(1):25～30
[11] Margrave G and Daley P F. Recursive Kirchhoff wavefield extrapolation. CREWES research report, 2001, 13 : 617-629
[2] Volker A W E et al. Analysis and optimization of 3-D seismic acquisition geometries by focal beams. SEG Expanded Abstracts, 2000
[3] Berkhout A J et al. Comprehensive assessment of seismic acquisition geometries by focal beams-Part I: Theoretical consideration. Geophysics, 2001,66(3): 911-917
[4] Volker A W E et al. Comprehensive assessment of seismic acquisition geometries by focal beams-Part II: Practical aspects and examples. Geophysics, 2001,66 (3):918~931
[5]别尔克豪特A J著;马在田等译．地震偏移——波场 外推法声波成像．北京:石油工业出版社,1983
[6]狄帮让等．三维观测系统优化设计的双聚焦方法．石 油地球物理勘探,2003,38(5):463～469
[7] Cao Wei-ping et al. Migration spatial resolution esti mation algorithm for stratified medium with focal beams. SEG Expanded Abstracts .2003
[8]倪成洲等．层状介质双聚焦方法优化观测系统设计软 件的开发．石油地球物理勘探,2004,东部会议专刊:5 ～8
[9] Veldhuizen E J et al. Acquisition geometry analysis u-sing quantitative measures for image quality. SEG Expanded Abstracts ,2003
[10]狄帮让等．孔径角对三维波场外推精度的影响．石油 地球物理勘探,2005,40(1):25～30
[11] Margrave G and Daley P F. Recursive Kirchhoff wavefield extrapolation. CREWES research report, 2001, 13 : 617-629
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