Z-99 P-WAVE AND CONVERTED WAVE EVENT CORRELATION BY CONVERTED WAVE MOVEOUT ANALYSIS

A reliable correlation between the P-wave and converted-wave (C-wave) events is critical for multicomponent data processing and interpretation. Recent studies show that the C-wave moveout in layered isotropic media can be determined by two parameters: the C-wave stacking velocity Vc2 and velocity ratio γiso. Based on this theory, it is possible to obtain an independent estimate of the P-wave stacking velocity Vp2 as a function of C-wave vertical travel time Tc0 from C-wave reflection moveout. These estimates of Vp2 in Tc0 can then be compared to the Vp2 obtained from P-wave reflection moveout in order to establish the corresponding relationship between P-wave vertical travel time Tp0 and C-wave time Tc0. Velocity ratio γiso is a key parameter that determinates the reliability of Vp2 in Tc0. Semblance analysis is performed to resolve C-wave stacking velocity Vc2 and γiso. An analysis of a layered model shows that a reliable correlation can be achieved for layered media. Field 4C data from Ordos Basin, China, are used to illustrate the application