Using Horizontal Well Technology for Enhanced Recovery in Very Mature, Depletion Drive Gas Reservoirs - Pirkle #2 Well, A Case History, Carthage (Lower Pettit) Field, Panola County, Texas

Horizontal well technology has been successfully applied to exploit reservoirs involving thin beds, low permeability zones, naturally fractured reservoirs, high-cost areas, and zones of water coning. The Pirkle No. 2 well represents the first use of horizontal technology to enhance ultimate gas recovery in a very mature, low pressure zone in the Lower Pettit horizon at Carthage Field, Panola County, Texas. The Pirkle No. 2 well was drilled to test the concept that a horizontal well could enhance ultimate recovery by lowering the final abandonment pressure in a very mature, depletion drive gas reservoir. However, numerous technical obstacles existed to the successful drilling and completion of an economic well in a 0.0308 psi/ft pressure gradient environment. This paper outlines the steps taken by OXY team members in planning and executing the project, as well as the results achieved from the Pirkle No. 2 well. Information gained from this project will help others to define appropriate screening criteria and provide dance for planning/application of horizontal technology to guide other mature gas reservoirs worldwide.