Decoupling-Equation-Based Elastic Reverse Time Migration Using S-Wave Source

Imaging using S-wave seismic data based on elastic media holds the potential to address certain critical issues that conventional P-wave imaging cannot resolve, thereby offering new opportunities for oil and gas exploration. In this article, we have developed a feasible S-wave reverse time migration (RTM) imaging technique. Based on nonconversion elastic wave theory, we introduce auxiliary variables to construct a first-order pure S-wave equation, which is used to simulate the extrapolation of source wavefields in S-wave RTM. In addition, we employ the first-order velocity-stress equation for backward propagation and use decoupled elastic operators for decoupling of receiver wavefields, and utilize vector cross-correlation imaging conditions to obtain scalar imaging results. Compared with traditional P-wave RTM, the proposed S-wave RTM in this article addresses the limitations of traditional P-wave RTM in processing S-wave seismic data, demonstrating its advantages in reacting to reservoir fluid in the field of oil and gas exploration.