CO2 Pilot Design in the Naturally Fractured Spraberry Trend: Project update and Upper Spraberry Rock Model

Thomas D. Sheffield, Paul McDonald, David S. Schechter, Richard Baker, and Lawrence Teufel

The Spraberry Trend area within the providence known as the Permian Basin, encompasses a productive area greater than 2,500 sq mi. The Spraberry was once deemed, "The largest uneconomic field in the world." The marginal economics and low recovery rates with the Spraberry are well documented and have helped to prevent any comprehensive reservoir characterization and yet the field continues to produce nearly 60 MBOPD. The Spraberry Trend reserves are estimated to contain 10 Bbls OOIP of which less than 10% has been recovered. CO2 injection has never been attempted in the Spraberry due to the naturally occurring fracture network, which has been known to dominate both initial production and subsequent waterflood performance. Before a CO2 pilot design can be implemented, detai ed geologic characterization of the Upper Spraberry must be done. This paper will describe the rock model developed from the initial core well within the pilot area as well as the minimum and maximum stress states that occur in situ.

Results:

From a detailed rock model within the Upper Spraberry as to the porosity and permeability relationships that exist in situ, along with fracture characterization, flow characteristics can be determined which will be used in the pilot design.

AAPG Search and Discover Article #91019©1996 AAPG Convention and Exhibition 19-22 May 1996, San Diego, California