【摘要】 近年来,我国部分老油区勘探开发难度日益增大,勘探目标逐渐转向裂缝油气藏和岩性油气藏等,研究弹性多波理论下的叠前深度偏移算法至关重要。根据高斯束偏移的高效性和逆时偏移的高精度,将弹性多波逆时偏移的实现思想应用于高斯束叠前深度偏移中,研究了一种弹性多波高斯束逆时偏移方法。在射线中心坐标系下,以二维弹性波KirchhoffHelmholtz积分为基础,根据多分量地震数据的矢量地震波场传播特征,利用弹性动力学高斯束表征的格林张量推导了弹性波波场正、反向延拓公式和相应的成像公式,并针对转换波的极性反转问题,提出了一种根据入射波入射角的正、负引入符号函数的校正方法。模型和实际资料试算结果验证了该方法的正确性和适用性。更多还原

【Abstract】 In recent years,the exploration and development of some old oilfields became more and more difficult,exploration target is gradually turning to fractured reservoirs and lithologic reservoirs,so it is important to study prestack depth migration under the theory of elastic wave.Considering the high-efficiency of Gauss beam migration and high-precision of reverse time migration,a Gauss beam reverse time migration for elastic multiple wave has been proposed by applying the idea of reverse time migration to Gaussian beam prestack depth migration.In ray centered coordinates,according to the propagation characteristics of vector wavefield in multi-component seismic data,we derive the forward and backward extrapolation formula and their corresponding imaging formula of vector wavefield by using Green tensor characterized by elastic dynamics Gauss beam on the basis of 2DKirchhoff-Helmholtz integral for elastic wave,and propose a correction method through adding the sign function related to the positive and negative of incident angle to solve the polarity reversion of PS-wave.Examples of model and real data verify the correction and applicability of this method.更多还原