Abstract: Horizontal Drilling a Success in West Cement Medrano Unit, Caddo County, Oklahoma

Kenneth F. Bridges, William T. Siemers, Dennis R. Presbindowski

In May, 1993, Phillips Petroleum Company successfully completed the West Cement Medrano Unit ^sharp71 horizontal well for 1,806 barrels of oil per day. The horizontal leg is 4,070 feet long and was drilled at a true vertical depth of 6,047 feet in the Medrano Sandstone (Pennsylvanian), between the gas/oil and gas/water contacts. The well replaced nine vertical producers in the unit which were experiencing severe gas coning problems. An interactive,

multidisciplinary, teamwork approach involving geology, engineering, land, and research was directly responsible for the success of the project.

The West Cement Medrano Unit is located in Caddo County, south-central Oklahoma. The target reservoir dips approximately 23° toward the southwest. The Cement structure occurs in the axial portion of the Anadarko basin and developed during Early Pennsylvanian time in response to the regional compressional tectonic regime associated with the Wichita Orogeny. Pennsylvanian strata were pushed upward and thrust northward, folding the beds on the up-thrown block into an anticlimal structure that is fault-bounded on its northern limit.

A good understanding of the petrologic character of the Medrano reservoir, especially of the depositional framework, reservoir geometry, and lithologic character, was a significant factor in the success of the well. The thin- to thickly bedded, clean, well sorted, fine- to medium-grained, quartz arenite to sublitharenite reservoir sandstones were deposited as delta-front sands (primarily as distributary and distal mouth bar sands) along a NW-SE trending basin margin. Internally, the sandstones are massive or they exhibit fine ripple lamination, low-angle cross lamination, and parallel planar lamination. The good lateral and vertical uniformity of the sandstones produces a regional and stratigraphic homogeneity in reservoir character that makes the Medrano Sandstone an excellent candid te for horizontal drilling.

AAPG Search and Discovery Article #90986©1994 AAPG Annual Convention, Denver, Colorado, June 12-15, 1994