- Copyright © 2004 Society of Exploration Geophysicists
The goal of this multicomponent (C-wave) design methodology is to transfer the well-known principles of the P-wave design process to the design of the acquisition of a C-wave survey. The optimum result is a C-wave seismic survey with bin-to-bin attributes of uniform fold, azimuth, and offset.
It is assumed that most C-wave surveys will be recorded in conjunction with a P-wave survey. Therefore, in this article, an example C-wave “fitted” survey will be presented within the framework of the P-wave design parameters. Alterations to the P-wave survey are normal and usually require more field effort along with increased cost. The fundamentals demonstrated within this article apply to both land and ocean-bottom cable C-wave acquisition. The concepts are developed from examples with first-order or asymptotic travel path assumptions. With some modifications, the methodology will handle more exact travel path equations such as described by Thomsen (1999).
A “teepee” (Thomas et al., 2004) is the subsurface earth volume containing the common reflection point locations of the time versus source-receiver offset (SR) volume for a 3D seismic trace gather. Trace gathers are commonly constructed using common source, common receiver, or hybrid (source and receiver) criteria. Once the P-wave surface coverage of maximum source-receiver offset, or aperture, is linked to the teepee, the P-wave design process simplifies into four issues. Determine: (1) the source and/or receiver station density to determine the desired bin dimension, (2) the amount of overlap of the teepees for the required survey fold, (3) the total number of teepees required to ensure an adequate full-fold image area, and (4) the balance of the source and receiver effort to achieve an economic survey. The attributes of the linked P-wave teepees are considered equal for all geologic layers of the earth model, because the VP/VS ratio (VPS …