The Bureau of Economic Geology's Reservoir Characterization Research Laboratory project, "Characterization of San Andres and Grayburg Reservoirs," was initiated in September 1988 and has completed the first year of a proposed 2-year program. Substantial progress has been made toward the goals of this program, which are focused on development of advanced approaches to reservoir characterization for improving recovery efficiency of substantial remaining mobile oil resources in these prolific reservoirs. Key research results are in the areas of (1) quantitative description and geostatistical modeling of interwell and reservoir-scale heterogeneity from San Andres outcrops, and (2) preliminary studies on integration of the quantitative outcrop models with a geologic/engineering characterization of the Seminole San Andres Unit.
Outcrop geologic studies were carried out at play, reservoir, and interwell scales along the Algerita Escarpment, Guadalupe Mountains, New Mexico. This 17-mile play-scale study area provides a dip-section framework for detailed investigations and serves as an analogous reservoir framework for comparison with producing San Andres fields. Reservoir-scale mapping of a 4-mile dip section of the upper San Andres with measured sections spaced 1,000 to 2,000 ft apart demonstrates the compartmentalization of individual grainstone shoal complexes on the scale of several thousand feet laterally and 50 to 100 ft vertically.Bureau of Economic Geolog
