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在实际地球介质中传播的地震波会产生衰减和频散现象,因此其更接近于黏弹性介质,在地震处理中补偿这些黏性影响是十分必要的。基于波动方程的叠前深度偏移中进行吸收衰减补偿更准确,也更有物理意义,直接求解双程波动方程的逆时偏移(RTM)能够成像大倾角复杂构造,具有诸多优势。然而当考虑吸收衰减补偿时通常会产生不稳定现象,大部分研究都是在逆时偏移的波场延拓中进行波数域的低通滤波来解决这个问题。本文采用广义标准线性固体的黏声波动方程进行吸收衰减补偿的Q-RTM方法,通过添加正则化项的方式来稳定延拓过程。添加正则化项本质上是低通滤波,滤波窗口是指数形式,在时空域有明确的形式,可以阻止发生高频不稳定。与直接滤波相比,正则化参数可以是空变的,因此比较适合剧烈变化的区域,我们还发现震源归一化互相关成像条件更适合Q-RTM方法。
Seismic waves propagating in the real earth medium will produce attenuation and dispersion phenomena. Therefore, they are closer to the viscoelastic medium and it is necessary to compensate these viscous effects in seismic processing. Absorption and attenuation compensation in prestack depth migration based on the wave equation is more accurate and more physical. Direct solution of the RTM of the two-way wave equation can image large-dip complex structures with many advantages. However, when considering the absorption and attenuation compensation, the instability usually occurs. Most of the research addresses this issue by performing low-pass filtering in the wave number domain in inverse time migration wavefield extension. In this paper, the Q-RTM method of absorbing attenuation compensation using the visco-acoustic wave equation of generalized standard linear solid is adopted to stabilize the continuation process by adding regularization term. The addition of the regularization term is essentially low-pass filtering, the filtering window is exponential and has a definite form in the space-time domain to prevent the occurrence of high-frequency instability. Compared with direct filtering, the regularization parameter can be space-dependent, so it is more suitable for the area that changes drastically. We also find that the normalized cross-correlation imaging conditions are more suitable for the Q-RTM method.