投影解析速度建模
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摘要
当今地球动力学的研究已逐步引起重视 ,尤其是高新探测技术的发展 ,将会大大加快其研究步伐。地球物理勘探作为重要的探测技术之一 ,已在该领域做出了重要贡献 ,比如能源探测、环境保护、防灾减灾工作中都需要物探技术。文中就地震勘探领域中地震波成像前沿技术———深度偏移的核心问题———速度模型的建立展开深入的研究。在分析现有方法缺陷的基础上 ,提出投影解析速度建模方法。该方法建立在两个重要事实依据之上 :(1)地震波旅行时误差是由描述地下反射界面的深度误差和描述地层的速度误差共同引起的 ;(2 )在反演中要保证零炮检距旅行时不变。在局部平面波前假设和拉东投影原理下 ,导出由旅行时误差计算界面深度误差和速度误差的解析公式。该方法可保证界面深度和层速度同步快速收敛。与现有方法相比 ,该解析法可以明显提高计算效率 ,且应用效果相当明显。
The research on dynamic of the earth is progressively attached importance to at present. With the development of high\|accuracy and new survey technology,the research will be speeded up. As one of the important survey technologies, geophysical prospection has contributed a lot to the energy survey,environmental protection and natural disasters prevention and reduction.Depth migration is one of the frontier technologies for seismic wave imaging in seismic exploration. This paper makes a detail study for subsurface velocity model\|building which is the core of depth migration. Based on the drawback analysis of the ready\|made methods, the projecting analytical method is put forward. The method is established on two important factual evidences. First, the seismic wave traveltime error is caused jointly by the depth error of reflection horizon and the interval velocity error for describing the subsurface formation. Second, the seismic wave traveltime at zero offset section does not change in seismic inversion. According to the assumption of local plane wavefront and Radon projecting principle, the analytical formulae of interface depth error and interval velocity error are derived from the seismic wave traveltime error.The method can ensure the convergence of depth to the interface and interval velocity to go on synchronously and speedily.By comparison with those ready\|made methods, the analytical method can promote distinctly the calculation efficiency and its application effect is good enough also.
The research on dynamic of the earth is progressively attached importance to at present. With the development of high\|accuracy and new survey technology,the research will be speeded up. As one of the important survey technologies, geophysical prospection has contributed a lot to the energy survey,environmental protection and natural disasters prevention and reduction.Depth migration is one of the frontier technologies for seismic wave imaging in seismic exploration. This paper makes a detail study for subsurface velocity model\|building which is the core of depth migration. Based on the drawback analysis of the ready\|made methods, the projecting analytical method is put forward. The method is established on two important factual evidences. First, the seismic wave traveltime error is caused jointly by the depth error of reflection horizon and the interval velocity error for describing the subsurface formation. Second, the seismic wave traveltime at zero offset section does not change in seismic inversion. According to the assumption of local plane wavefront and Radon projecting principle, the analytical formulae of interface depth error and interval velocity error are derived from the seismic wave traveltime error.The method can ensure the convergence of depth to the interface and interval velocity to go on synchronously and speedily.By comparison with those ready\|made methods, the analytical method can promote distinctly the calculation efficiency and its application effect is good enough also.
引文
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[2 ] StorkC ,ClaytonRW .Linearaspectsoftomographicvelocityanalysis[J].Geophysics,1991,5 6 (4) :483～ 495 .
[3] StorkC .Reflectiontomographyinthepostmigrateddomain[J].Geophysics ,1992 ,5 7(5 ) :6 80～ 6 92 .
[4 ] BishopTN ,BubeKP ,CutlerRT ,etal.Tomographicdeterminationofvelocityanddepthinlaterallyvaryingmedia[J].Geophysics,1985 ,5 0 :90 3～ 92 3.
[5 ] BordingRP ,GersztenkornA ,LinesLR ,etal.Applicationofseismictraveltimetomography[J].GeophysJRAstrSoc 1987,90 :2 85～ 30 3.
[6 ] KosloffD ,ZackhemUI ,KorenI .Subsurfacevelocitydeterminationbygridtomographyofdepthmigratedgathers[A].6 7thAnnInternatMtg ,SocExplGeophys ,ExpandedAbstracts[C],1997.1815～ 1818.
[7] CarrionP .Dualtomographyforimagingcomplexstructures[J].Geophysics,1991,5 6 :136 5～ 1376 .
[ 8 ] HoleJA .Nonlinearhighresolutionthree dimensionalseismictraveltimetomography[J].JournalofGeophysicalResearch ,1992 ,97(B5 ) :6 5 5 3～ 6 5 6 2 .
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