Analysis and application of pseudo-offset method in the converted-wave prestack time migration

Pseudo-offset migration (POM) is a new method for prestack time migration of converted waves that improves on equivalent-offset migration (EOM). The mapping of POM is different than EOM but the purpose of the two methods is to map the input samples to the common conversion scatter point (CCSP) gathers. This paper introduces the principles of the two migration methods and model parameter sensitivity tests for both POM and EOM. At large offset-to-depth ratios the hyperbolic approximation , the three-term approximation and the double square root (DSR) equation are used to NMO-correct the mapped POM gathers to obtain more accurate migration velocities. These equations were derived and calculated by small pseudo offset. POM is then used to image complex structure and prestack time migration.