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Several parameters are needed to describe the converted-wave (C-wave) moveout in processing multi-component seismic data, because of asymmetric raypaths and anisotropy. As the number of parameters increases, the converted wave data processing and analysis becomes more complex. This paper develops a new moveout equation with two parameters for C-waves in vertical transverse isotropy (VTI) media. The two parameters are the C-wave stacking velocity (V C2) and the squared velocity ratio (γ vti ) between the horizontal P-wave velocity and C-wave stacking velocity. The new equation has fewer parameters, but retains the same applicability as previous ones. The applicability of the new equation and the accuracy of the parameter estimation are checked using model and real data. The form of the new equation is the same as that for layered isotropic media. The new equation can simplify the procedure for C-wave processing and parameter estimation in VTI media, and can be applied to real C-wave processing and interpretation. Accurate V C2 and γ vti can be deduced from C-wave data alone using the double-scanning method, and the velocity ratio model is suitable for event matching between P- and C-wave data.

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.