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Petroleum Technology Digest: Lightweight proppants in slick water fracs boost flush output, cut post-frac decline

Over time, various hydraulic fracturing treatments have been favored in the Southwest Westbrook Unit’s Clearfork reservoir in Mitchell County, Texas, depending on various operators and stimulation technology evolution. There is a natural tendency to stay with the “tried and true,” as regards both the technology and the service provider. While results with this philosophy may be acceptable, they are not necessarily optimum. Beginning in 2004, experimentation with slick water treatments using lightweight proppants began. Results showed that flush production following treatment was increased, and post-frac production decline was less severe. This applied to both new infill wells and recompletions. Success in 2004 led to continued development in 2005 and 2006, and plans for 2007. Exploitation through 2007 should boost unit recovery by 6.6 million bbl of oil. Individual well incremental reserves, ranging from 35,000 to 50,000 bbl, are quite attractive, even with very conservative economics.