粘声介质动态聚焦束逆时偏移

Reverse time migration with dynamic focused beams in viscoacoustic media

高斯束逆时偏移是一种兼具高斯束偏移灵活、高效和逆时偏移高精度特性的深度域成像算法,能够面向目标成像。粘滞性在地下介质中广泛存在,在成像过程中忽略其影响会导致成像位置-不准确和振幅欠估计等问题。基于高斯束逆时偏移,首先通过构建动态聚焦束算子,将地震波能量约束在一定范围内,解决了高斯束射线束宽度随传播距离增加而快速发散的问题;随后引入复值旅行时对震源点和检波点波场的吸收衰减效应进行补偿,实现了粘声介质动态聚焦束逆时偏移算法;最后通过数值测试验证了算法的可行性和适用性。

Reverse time migration with Gaussian beams is a depth-domain imaging algorithm that combines the flexibility and high efficiency of Gaussian beam migration and the high precision characteristics of reverse time migration which can be used for target imaging.The viscosity widely exists in the subsurface media,with ignoring its influence during the imaging process will lead to problems such as inaccurate imaging position and underestimation of amplitude.In this paper,based on the reverse time migration with Gaussian beams,the dynamic focused beam operator is constructed to constrain the energy of the seismic wave within the certain range,and the problem of rapid divergence of the Gaussian beam with the propagation distance is solved.Subsequently,the complex travel time is used to compensate the absorption and attenuation effect of the source and receiver wave field,and then the reverse time migration with dynamic focused beams for viscoacoustic media is realized.Finally,the feasibility and applicability of the algorithm are verified by numerical tests.