Abstract: Abstract: Application of Vertical Seismic Profile to Stratigraphic Exploration Problems, Powder River Basin, Wyoming

A. H. Balch, M. W. Lee, R. T. Ryder

Vertical seismic profiling (VSP) is a combined well-logging and surface-exploration seismic technique that measures the evolution of the entire wave field both vertically and horizontally. The VSP technique has been known for many years; however, recent advances in seismic-data recording and processing have greatly increased its potential applications.

Our current objective is to investigate the applications of the VSP to stratigraphic-trap detection and other stratigraphic-exploration problems. Our approach is twofold. First, the VSP is used to measure accurately in boreholes the in-situ acoustic parameters of specified stratigraphic end members (such as reservoir and nonreservoir conditions) under field conditions. Second, if measurable differences exist between end members, the VSP is employed in designing an experiment to optimize the detection of these acoustic variations using conventional surface-seismic measurements.

VSP data have been obtained with true-amplitude digital-recording equipment in three water wells along the east flank of the Powder River basin, Wyoming: (1) Bechtel E.T.S.I. O-1, Sec. 28, T36N, R62W, Niobrara County; (2) Coronado Collins W-1, Sec. 33, T45N, R61W, Weston County; (3) U.S.G.S. Madison HTH 1, Sec. 15, T57N, R65W, Crook County. Processing techniques applied to the data include true-amplitude processing, wavelet derivation, velocity filtering, and spectral analysis. Field data, processing results, and tentative conclusions have shown stratigraphic variations in the Minnelusa and Sundance Formations, and in the Madison Limestone and equivalent units.

AAPG Search and Discovery Article #90969©1977 AAPG-SEPM Rocky Mountain Sections Meeting, Denver, Colorado