By OGJ editors
HOUSTON, Aug. 17 -- The Wyoming Oil & Gas Conservation Commission has approved 10-acre density for drilling in the Lance and Mesaverde formations in parts of giant Pinedale Anticline gas field in the Green River basin.
Subsidiaries of Questar Corp., Salt Lake City, operate the affected acreage.
The newly approved 10-acre density locations join 10-acre pilot locations in other Pinedale field areas included in a pilot program that WOGCC approved on July 19, Ultra Petroleum Corp., Houston, said. Ultra operates the pilot.
Operators have estimated that Pinedale Anticline field has more than 40 tcf of original gas in place (OGIP), according to WOGCC.
With the benefit of additional 10-acre pilot well results and data on older wells, Questar estimated that gross recoverable reserves for 10-acre density wells will be 2-7 bcfe/well.
In testimony before the WOGCC, Questar presented data indicating 20-acre density wells will recover about one quarter of OGIP, and that 10-acre-density wells will recover a little less than half of OGIP.
When developed on 10-acre density Questar expects to have an average 67% working interest in 932 Lance Pool wells. The WOGCC 10-acre approval covers 12,700 acres, which Questar currently believes to include the productive limits of its core acreage in Pinedale field.
Ultra has an average 28% working interest in Questar's Stewart Point and Mesa areas of Pinedale Anticline in Sublette County, Wyo.
Since 2003, the WOGCC has approved 11 applications by six operators for increased density in the Pinedale Anticline. Seven applications included the drilling of 232 wells on 20-acre density and four contained 381 wells on 10-acre density.
Beside Questar and Ultra, the companies involved are Shell Oil Co., Lance Petroleum (a subsidiary of Western Gas Resources), Petrogulf Corp., Denver, and Yates Petroleum Corp., Artesia, NM.
WOGCC Oil and Gas Supervisor Don Likwartz said, "Since there's some overlap in a few of the dockets, the total area covered is 19,900 acres out of a total proven field area of 51,000 acres. Pinedale Anticline is on statewide 40-acre spacing, except for the referenced areas covered by the 11 dockets."