Recent advances in optimized geophysical survey design

Abstract

Survey design ultimately dictates the quality of subsurface information provided by practical implementations of geophysical methods. It is therefore critical to design experimental procedures that cost effectively produce those data that maximize the desired information. This review cites recent advances in statistical experimental design techniques applied in the earth sciences. Examples from geoelectrical, crosswell and surface seismic, and microseismic monitoring methods are included. Using overdetermined 1D and 2D geoelectrical examples, a minor subset of judiciously chosen measurements provides a large percentage of the information content theoretically offered by the geoelectrical method. In contrast, an underdetermined 2D seismic traveltime tomography design study indicates that the information content increases almost linearly with the amount of traveltime data (source-receiver pairs) considered until the underdeterminancy is reduced substantially. An experimental design study of frequency-domain seismic-waveform inversion experiments reveals that a few optimally chosen frequencies offer as much subsurface information as the full bandwidth. A nonlinear experimental design for a seismic amplitude-versus-angle survey identifies those incidence angles most important for characterizing a reservoir. A nonlinear design example shows that designing microseismic monitoring surveys based on array aperture is a poor strategy that almost certainly leads to suboptimal designs.