Abstract

Over 450 horizontal oil and gas wells have been drilled and completed since 2002 in the Granite Wash trend in a five-county area (Wheeler County, Texas; Roger Mills, Beckham, Washita and Custer Counties, Oklahoma) of the deep Anadarko Basin of Texas and Oklahoma. Over 90% of the horizontal wells drilled to date have targeted Granite Wash strata in the Desmoinesian Series of Pennsylvanian age and have been drilled since January 2008. As of June 30^th, 2011, 699 horizontal drilling permits have been issued for wells targeting the various Granite Wash horizons in the area.

Before 2007, the Granite Wash reservoirs had been exploited by over 2000 vertical wells across the report area. These vertical wells are generally characterized by poor recovery efficiency and economic performance due to the extremely low permeability of the various arkosic sandstone and conglomerate reservoirs. Horizontal drilling and completion technology now provide the oil and gas industry with much better tools for efficiently producing gas, oil and condensate from these reservoirs.

Daily production from horizontal Granite Wash completions in the five-county area as of June 30, 2011 is estimated to include 41,000 barrels of oil and condensate, 73,500 barrels of natural gas liquids and 580 million cubic feet of gas. Total cumulative production from 374 horizontal wells with available production data has reached 15.3 million barrels of oil (MMBO) and 351 billion cubic feet of gas (BCFG). It is estimated that 33.4 MM barrels of natural gas liquids (NGL’s) have been processed from the natural gas stream, providing a net of 263 billion cubic feet of produced gas at a 25% shrinkage factor.

This report will include geologic descriptions of the Granite Wash play, a look at four key oil and gas “sub-play” areas that have been horizontally drilled as well as a discussion of the location, participants and results of the drilling activity through mid-2011.