Abstract

Barnhart Field was discovered in 1941 on the Ozona Uplift, southeast 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 than 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 control production because the southern part produced slightly more oil than the northern part. Insoluble residue analyses and lateral-log correlations indicate that the northern part of the field has been more deeply eroded than 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 porosity in its coarse crystalline dolomite. Secondary recovery operations have begun in a unit located on the University Lands in the southern part of the field.