Automated time-domain transform of converted waves by prestack double-parameter scanning

Abstract

As the velocity ratio of P- to S-wave is the major parameter for the time matching of a converted wave (C-wave) transformed from the C-wave time domain into the P-wave time domain, the event registration of the P-wave and C-wave in multicomponent seismic exploration data processing and interpretation is generally based on the poststack sections to obtain the velocity ratio model. In this paper, we represent the two-parameter (VC2 and γiso) normal moveout equation of the C-wave and propose the double-parameter scanning (DPS) method for matching the processing workflow based on C-wave prestack gathers. And we derive a calculation method to obtain the velocity ratio model, which can be used to transform the C-wave section into the P-wave time domain. The proposed DPS method and matching workflow are used to evaluate the precision of the normal moveout equation and the event registration of the P-wave and C-wave seismic sections. Finally, we use synthetic data to analyze the precision of the two-parameter equation, and the real field data is verified for the C-wave section time-domain transform. It turns out that the DPS method can be used to time the transform directly and automatically from the velocity analysis of the C-wave. The time-domain migrated section from the C-wave to P-wave should further be processed by other matching techniques to improve the event registration of the C-wave and P-wave. © 2013 Sinopec Geophysical Research Institute.