(1) Colorado School of Mines, Golden, CO
ABSTRACT: Lithology and Fluids: Seismic Models of the Brushy Canyon Formation, West Texas
Lithology and fluid information can be extracted from seismic data of deepwater clastics if their relative contribution to the signal is understood. Many factors combine to produce a seismic signature including stratal architecture, lithology, pore fluids, age, compaction, pore pressure, and near surface heterogeneities. Outcrop seismic models are constructed of the Brushy Canyon Formation along the Western Escarpment of the Guadalupe Mountains using rock and fluid properties from outcrop, normal and overpressured Gulf of Mexico and North Sea Basins to test seismic sensitivity to lithology, fluid, and pressure. Resolution is best in large, clean, gas-saturated, and over-pressured sandstones. Strong lithology contrasts improves resolution of km-scale sand bodies. Hydrocarbon saturation does not necessarily enhance seismic response. Lithology and fluid affects can reduce impedance contrast resulting in low amplitudes (dim spots). In contrast, elevated geopressures preserve porosity and produce low-velocities and high amplitudes (bright spots). Even in low impedance contrast sandstone and shale intervals, offset dependent amplitudes increase resolution and indicate hydrocarbons.
AAPG Search and Discovery Article #90906©2001 AAPG Annual Convention, Denver, Colorado