Seismic and Magnetotellurics Combined, A Case History of the South Clay Basin Prospect

Abstract The exploration of the South Clay Basin, Utah, prospect is presented as an example of an integrated geophysical program where magnetotelluric and seismic data have been used together to successfully define a subsurface structure. The prospect, just south of the prolific Clay Basin gas field, is marked by Precambrian rocks on the surface and rugged topography. The object of the geophysical program was to determine if the visible Precambrian was present in an overthrust situation, and if so, to identify the structural configuration of the subthrust sedimentary rocks. The integration of magnetotelluric and seismic data for the South Clay Basin prospect has yielded a cost-effective, credible interpretation under difficult surface conditions in an area of limited seismic and subsurface control. The MT has provided valuable stratigraphic control to the seismic interpretation. Use of the MT with the seismic has produced a structure map for a small fraction of the cost of obtaining similar coverage through seismic alone.