Multicomponent Data Processing
Multicomponent seismic data processing is a complex subject that would require a separate book to cover all aspects o the topic in a thorough manner. This chapter summarizes only basic principles and is not intended to be a complete treatise on multicomponent data-processing concepts and strategies.
When nine-component (9C) data are acquired, processing S-wave data propagating in isotropic media is in concept no different than processing conventional single-component P-wave data because SH-SH and SV-SV modes satisfy the constraints of common-midpoint (CMP) data processing just as P data do. The fundamental requirement for CMP processing is that the velocity of the downgoing mode must be the same as the velocity of the upgoing mode. That assumption is valid for SH-SH and SV-SV data just as it is for P-P data. Because CMP data-processing software and expertise are widespread, processing 9C data to make SH-SH and SV-SV images is not a great challenge to a data processor skilled in processing conventional P-P data.
Processing three-component (3C) and four-component (4C) data is a different matter. For those data, the velocity of the downgoing wavefield (P-wave) is not the same as the velocity of the upgoing wavefield (SV-wave), and CMP principles no longer apply. A different data-processing strategy based on common-conversion-point (CCP) principles has to be implemented. Some of the better CCP processing software is proprietary to seismic contractors and to a few research groups and service providers. The use of CCP software is beginning to be reasonably widespread, and CCP data-processing skills are expanding annually.