【摘要】 为提高地震成像结果的准确性并真实反映实际地震波场在介质中的传播特性,应该充分利用多分量地震数据的矢量特征进行弹性波成像,其中,最为棘手的问题是纵横波偏移速度场的确定,为此,本文提出了直接利用多分量地震数据进行弹性波角度域偏移速度分析的方法.基于空移成像条件的弹性波Kirchhoff偏移方程提取了弹性波局部偏移距域共成像点道集,通过Fourier域角度分解求得以纵波入射角为参数的弹性波角度域共成像点道集.利用提出的反射纵波和转换横波成像深度一致性准则,依据导出的弹性波角度域共成像点道集剩余时差方程分别对纵波、横波偏移速度进行了更新.在此基础上,实现了弹性波Kirchhoff叠前深度偏移速度分析.实例表明,本文提出的弹性波偏移速度分析方法具有可行性和可应用性.更多还原

【Abstract】 To improve the accuracy of seismic imaging and describe the propagation of seismic wavefield more exactly,we need to take full advantage of the vectorial multicomponent seismic data to conduct the elastic wave imaging.However,the great challenge of elastic wave imaging is the determination migration velocity of P-and S waves.Based on multicomponent seismic data angle-domain common-image gathers(ADCIGs),elastic wave migration velocity analysis is proposed in this paper.Firstly,according to the elastic Kirchhoff migration equation which is based on space shift imaging condition,P-and PS converted waves subsurface offset-domain common-image gathers(SODCIGs)are extracted and transformed into P-incidence angle-domain common-image gathers(P-ADCIGs)for P-and PS converted waves through the angle decomposition in the Fourier domain,respectively.Secondly,P-and PS converted wave residual movement equations were derived,and velocity analysis criteria of image depth consistency for Pand PS converted waves at the same reflector were proposed.We iteratively update the velocities based on residual movement equations for P-and PS converted wave angle-domain common-image gathers.On this basis,elastic wave migration velocity analysis is implemented.The example illustrates that elastic wave migration velocity analysis is successfully applied to the multicomponent seismic field data,suggesting that the method is feasible and applicable.更多还原