A Study On The Key Techniques Of Converted-Wave Seismic Data Processing And The Application

Converted-wave seismic data processing is the most important part of multicomponent seismic exploration research. CCP is the key technique of converted-wave seismic data processing. Because of the asymmetry of downgoing and upgoing travel path segments, gathering converted-wave data using a conventional sorting scheme based on common source-receiver midpoint smears the reflection points over the subsurface widely, which will compromise both signal-to-noise ratio and structure resolution. Another effect of this scheme is the lateral translation for structural events of converted-wave reflection; moreover, the time-distance curve of converted-wave is non-hyperbolic, so the conventional formulas based on hyperbolic is not acceptable for converted-wave velocity analysis and moveout correction.Common conversion point (CCP) binning , non-hyperbolic normal moveout (NMO) and converted-wave velocity analysis based on non-hyperbolic NMO are the key points to CCP stacking for converted-wave. All the conventional CCP gathering programs are exact and can provide a focused image at a given subsurface, however, reflectors above or below the selected subsurface will appear obscure.The subject aims the converted-wave seismic data processing by applying the technique more efficiently based on the achievements gotten already and the technique exists. By comparison with P-wave, the partial key points, CCP binning and converted-wave velocity analysis, are discussed emphatically which are different from those of the P-wave seismic data processing; according to the ratio of V_p to V_s changed with time and distance, we present formulas for CCP points and non-hyperbolic time-distance relation which are changed with layers and source-receiver distance and fit for arbitrary reflecting boundaries, and as well, make a study on the CCP binning based on time windows and introduce some kinds of methods to acquire the ratio of V_p to V_s; by constructing some modules we find a way of solving practical problems and also solve some problems in converted-wave seismic data processing; with the direction of this theory we have a try on the western area seismic data and make a favorable result.This paper mainly includes all those contents: the theoretical basis of converted-wave fluctuating equation, the partial general key techniques of converted-wave seismic data processing, a study on the partial key techniques of converted-wave seismic data processing (CCP binning, converted-wave velocity analysis and acquire the ratio of V_p to V_s) and applied examples in practice.