Abstract: Lithologic Color-Coded Sections by AVO Crossplots

Richard W. Verm, Fred J. Hilterman

AVO processing and interpretation can yield a "lithologic section" through a two-step process. First, the well-log curves are analyzed to establish the normal-incidence reflectivity (NI) and Poisson reflectivity (PR). These (NI,PR) pairs are then crossplotted for visual analysis of the grouping of the lithologic boundaries, such as shale over a water-saturated sand or a shale over a gas-saturated sand. The second step uses NI and PR reflectivity sections extracted from seismic data through AVO inversion. The two reflectivity sections are combined into a single color section by assigning each time sample, t, a color based on the separation of the expected lithologic boundaries in the NI vs PR crossplot conducted in the first step. The color on the resulting section then co relates to the lithologic boundaries established in the petrophysical calibration. The entire procedure is performed interactively on a workstation.

AAPG Search and Discovery Article #90960©1995 AAPG Southwest Section Meeting, Dallas, Texas