多波深度域建模与成像一体化技术

在复杂油气藏勘探中,常规方法在处理多波数据时通常将纵波和转换横波分别做类纵波处理,忽略了地震波的弹性矢量波特征,并且成像精度严重依赖于波场分离的精度。针对这些问题,本文给出了解耦的高斯束弹性波波场反向延拓公式及多波成像公式以实现叠前深度偏移;然后建立了针对弹性多波建模的最小二乘反演方程,以实现基于高斯束角道集的反射层析建模。将深度偏移和反射层析联合在同一处理流程中,前者为后者提供建模角道集和成像质量监控,后者为前者提供成像速度场,两者交替迭代形成深度域建模与成像一体化技术。模型试算和实际资料处理结果验证了一体化技术的正确性和有效性。

Integration of multi-wave depth model building and imaging

S-wave is separately processed with P-wave approaches in the conventional multi-wave data processing, which ignore elastic vector characteristics of seismic wave, and its imaging is critically dependent on the accuracy of the wavefield separation. In this paper, we propose an integrated approach for multi-wave depth model building and imaging. First we provide the back propagating formula of elastic wavefield decoupling of P- and S- waves for prestack depth migration, then construct the least square inversion equation of elastic wave to realize the reflection tomography based on Gaussian beam ADCIGs (angle domain common imaging gathers). In this way, depth migration and reflection tomography are integrated in the same processing flow. The former can provide ADCIGs and imaging quality control; and the latter can provide the final velocity model. Iterations between them form the integration approach of depth model building and imaging. Examples of model and real dataset validate the correctness and practicability of the proposed approach.