Analysis and optimization of 3‐D seismic acquisition geometries by focal beams

Abstract

Summary The acquisition geometry of a 3-D seismic survey should be designed in such a way that it fulfils the imaging requirements while satisfying the economical constraints. Focal source and focal detector beams are defined which describe the focusing properties of the source and detector geometry. These beams can be computed and evaluated separately. The computation of these beams can be done very efficiently using a Fourier transform of the source and receiver sampling function. In the case of a stationary spread the potential resolution and accuracy of AVP information can be obtained from these beams. Using the combination rules (per template) for the focal beams a relation between the basic template layout and the roll along distance can be derived in order to optimize the quality of the focal functions. This property can be used to design cost effective acquisition geometries. Conventional marine acquisition geometries yield strong side lobes of the resolution function in the cross-line direction due to the large distance between the sail-lines. By changing the source configuration the side lobe level can be reduced by at least 10 dB.