起伏地表采集数据的三维直接叠前时间偏移方法
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摘要
提出一种可对起伏地表采集的三维地震资料直接进行偏移成像的叠前时间偏移方法和流程.它用两个等效速度描述近地表和上覆层对地震波传播的影响,可对炮、检点不在同一水平面的三维地震资料直接进行叠前时间偏移处理.该方法不对近地表地震波传播做垂直出、入射假定,因此可适应高速层出露等不存在明显低、降速带情况.描述近地表和上覆层的两个等效速度参数可依据偏移道集的同相轴是否平直来确定,避免了确定近地表速度的困难;而对已知近地表速度的情况,则可进一步修正近地表速度,获得更好的成像效果.用三维起伏地表的理论数据和中国东部某工区实际数据验证了所发展方法和处理流程的有效性和实用性.
We present a 3D prestack time migration scheme and workflow that can image land seismic data without datum static corrections.The scheme mimics the influences of the near-surface and overlay on wave propagation using two equivalent velocities.As a result,it is not necessary for wave path to be vertical incidence in the near-surface,as in conventional static corrections.This leads to the proposed scheme which can handle the more complex surface cases,such as the exposure of high velocity in the near-surface.The proposed scheme can update the two equivalent velocities with respect to the flats and consistency of the events.A synthetic 3D dataset and a field 3D dataset without datum static corrections are used to demonstrate the scheme and the workflow.
We present a 3D prestack time migration scheme and workflow that can image land seismic data without datum static corrections.The scheme mimics the influences of the near-surface and overlay on wave propagation using two equivalent velocities.As a result,it is not necessary for wave path to be vertical incidence in the near-surface,as in conventional static corrections.This leads to the proposed scheme which can handle the more complex surface cases,such as the exposure of high velocity in the near-surface.The proposed scheme can update the two equivalent velocities with respect to the flats and consistency of the events.A synthetic 3D dataset and a field 3D dataset without datum static corrections are used to demonstrate the scheme and the workflow.
引文
[1]Sun C W,Jing P G,Pu Y.Seismic imaging in themountainous area of Southern China:Statics correctioncompared with migration from topography.SEG expandedabstract,2009.
[2]刘国峰,刘洪,李博等.山地地震资料叠前时间偏移方法及其GPU实现.地球物理学报,2009,52(12):3101-3108.Liu G F,Liu H,Li B,et al.Method of prestack timemigration of seismic data of mountainous regions and its GPUimplementation.Chinese J Geophys.(in Chinese),2009,52(12):3101-3108.
[3]Cox M.Static Corrections for Seismic Reflection Surveys.Tulsa:Society of Exploration Geophysics,1999.
[4]Bevc D.Flooding the topography:Wave-equation datumingof land data with rugged acquisition topography.Geophysics,1997,62(5):1558-1569.
[5]Kelamis P G,Erickson K E,Verschuur D J,Berkhout A J.Velocity-independent redatuming:A new approach to thenear-surface problem in land seismic data processing.TheLeading Edge,2002,21(8):730-735.
[6]Black J L,Brzostowski M A.Systematics of time-migrationerrors.Geophysics,1994,59(9):1419-1434.
[7]Reshef M.Depth migration from irregular surfaces withdepth extrapolation methods.Geophysics,1991,56(1):119-122.
[8]Rajasekaran S,McMechan G A.Prestack processing of landdata with complex topography.Geophysics,1995,60(6):1875-1886.
[9]Wiggins J W.Kirchhoff integral extrapolation and migrationof nonplanar data.Geophysics,1984,49(8):1239-1248.
[10]董春晖,张剑锋.起伏地表下的直接叠前时间偏移.地球物理学报,2009,52(1):239-244.Dong C H,Zhang J F.Prestack time migration includingsurface topography.Chinese J.Geophys.(in Chinese),2009,52(1):239-244.
[11]李世雄.波动方程的高频近似与辛几何.北京:石油工业出版社,2001.Li S X.Wave Equation with High Frequency Approximationand Symplectic Geometry(in Chinese).Beijing:PetroleumIndustry Press,2001.
[12]Zhang J F,Verschuur D J,Wapenaar C P A.Depthmigration of shot records in heterogeneous,transverselyisotropic media using optimum explicit operators.Geophysical Prospecting,2001,49(3):287-299.
[13]张廉萍,刘洪,李幼铭.单程波李代数深度积分的精度分析和算法改进.地球物理学报,2010,53(11):2739-2746.Zhang L P,Liu H,Li Y M.The precision analysis andalgorithm improvement in Lie algebra depth integral of one-way seismic wave.Chinese J.Geophys.(in Chinese),2010,53(11):2739-2746.
[14]张宇.振幅保真的单程波方程偏移理论.地球物理学报,2006,49(5):1410-1430.Zhang Y.The theory of true amplitude oneway wave equationmigration.Chinese J.Geophys.(in Chinese),2006,49(5):1410-1430.
[2]刘国峰,刘洪,李博等.山地地震资料叠前时间偏移方法及其GPU实现.地球物理学报,2009,52(12):3101-3108.Liu G F,Liu H,Li B,et al.Method of prestack timemigration of seismic data of mountainous regions and its GPUimplementation.Chinese J Geophys.(in Chinese),2009,52(12):3101-3108.
[3]Cox M.Static Corrections for Seismic Reflection Surveys.Tulsa:Society of Exploration Geophysics,1999.
[4]Bevc D.Flooding the topography:Wave-equation datumingof land data with rugged acquisition topography.Geophysics,1997,62(5):1558-1569.
[5]Kelamis P G,Erickson K E,Verschuur D J,Berkhout A J.Velocity-independent redatuming:A new approach to thenear-surface problem in land seismic data processing.TheLeading Edge,2002,21(8):730-735.
[6]Black J L,Brzostowski M A.Systematics of time-migrationerrors.Geophysics,1994,59(9):1419-1434.
[7]Reshef M.Depth migration from irregular surfaces withdepth extrapolation methods.Geophysics,1991,56(1):119-122.
[8]Rajasekaran S,McMechan G A.Prestack processing of landdata with complex topography.Geophysics,1995,60(6):1875-1886.
[9]Wiggins J W.Kirchhoff integral extrapolation and migrationof nonplanar data.Geophysics,1984,49(8):1239-1248.
[10]董春晖,张剑锋.起伏地表下的直接叠前时间偏移.地球物理学报,2009,52(1):239-244.Dong C H,Zhang J F.Prestack time migration includingsurface topography.Chinese J.Geophys.(in Chinese),2009,52(1):239-244.
[11]李世雄.波动方程的高频近似与辛几何.北京:石油工业出版社,2001.Li S X.Wave Equation with High Frequency Approximationand Symplectic Geometry(in Chinese).Beijing:PetroleumIndustry Press,2001.
[12]Zhang J F,Verschuur D J,Wapenaar C P A.Depthmigration of shot records in heterogeneous,transverselyisotropic media using optimum explicit operators.Geophysical Prospecting,2001,49(3):287-299.
[13]张廉萍,刘洪,李幼铭.单程波李代数深度积分的精度分析和算法改进.地球物理学报,2010,53(11):2739-2746.Zhang L P,Liu H,Li Y M.The precision analysis andalgorithm improvement in Lie algebra depth integral of one-way seismic wave.Chinese J.Geophys.(in Chinese),2010,53(11):2739-2746.
[14]张宇.振幅保真的单程波方程偏移理论.地球物理学报,2006,49(5):1410-1430.Zhang Y.The theory of true amplitude oneway wave equationmigration.Chinese J.Geophys.(in Chinese),2006,49(5):1410-1430.
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