TI介质中qP波方程逆时偏移技术的研究现状与展望

理论上说,TI介质逆时偏移技术更有利于解决各向异性介质的地震波成像问题,工业实践也证明了此项技术在解决复杂地层地震波成像问题方面的巨大潜力。总结了TI介质中qP波逆时偏移技术的研究现状,重点分析了qP波方程的建立、qP波方程的延拓算法和qP波成像方法这3个逆时偏移关键技术的实现思路和存在的主要问题,并在此基础上探讨了今后该领域的研究重点。分析认为,现有技术主要存在以下问题:①已有的TI介质qP波方程具有较高的运动学精度,但对方程的动力学精度缺乏深入研究;②qP波方程炮点波场重构中的随机边界技术存在不稳定隐患,业界在提升稳定性方面缺乏有效的解决方案;③二阶或高阶qP波方程难以准确求取qP波的坡印廷矢量,且现有的坡印廷矢量技术无法解决多组波场问题;④子波拉伸校正缺乏针对性技术等。因此,今后TI介质中qP波方程逆时偏移领域的研究重点应该包括qP波方程的动力学精度分析多参数随机边界设置技术和qP波传播方向的准确求取等方面。

Research status and prospect of qP wave reverse time migration in TI media

Reverse time migration for anisotropic media is more conducive to seismic imaging of anisotropic strata.The application practice in industry also proves the great potential of this technique in the seismic imaging of complex strata.The research status of qP wave reverse time migration technology in TI media was summarized.Three key technologies including the establishment of qP wave equations,the propagation algorithm of qP wave equations,and a qP wave imaging method were discussed in detail.Subsequently,the focus of future research was discussed.According to the analysis,the main limitations of the existing technology are as follows:in-depth research on the dynamic accuracy of existing qP wave equations was lacking;the random boundary in the reconstruction of the shot wavefields of the qP wave equations is unstable,although there is no effective way to improve the stability of this algorithm;it is difficult to obtain the qP wave Poynting vector from the second-order or higher-order qP wave equations,and the existing Poynting vector technology cannot solve the problem of multiple wave fields;finally,there is no effective solution to the problem of wavelet stretching in qP wave reverse time migration.Future research of qP wave equation reverse time migration in TI media should include the kinematic accuracy analysis of qP wave equation,the setting of a random boundary,and the accurate calculation of the qP wave propagation direction.