Abstract
Barnhart Field was discovered in 1941 on the Ozona Uplift, southeastern Reagan County, Texas. The field produces from the Ellenburger Group on approximately 10,000 acres that can be divided into a southern part on University Lands and a northern part on private land. Two pilot waterfloods were attempted; neither was successful. The field was essentially abandoned in 1976 after producing more that 16 million BO. The structure of the field is an asymmetrical anticline trending northeast – southwest with the crest on the northern part of the field. Structure alone does not appear to control production because the southern part produced slightly more oil than the northern part. Insoluble residue analyses and lateral-log correlations indicate the Ellenburger in the northern part of the field was more deeply eroded than in the southern part. The Ellenburger Group, in this field, can be divided into three pay zones, the Upper Honeycut, the Lower Honeycut and the Gorman. The Upper Honeycut produces only in the southern part of the field and may have the best developed porosity in coarse crystalline dolomite. An isopach of the Honeycut pay zones shows fair agreement between thickness and production. The Gorman pay zone does not correlate well indicating that production cannot be explained by gross isopachs alone.
