Wildcat to target Central Texas thrust front

April 17, 2000
A group of independents is to drill a wildcat west of the Ouachita thrust belt in central Texas east of an area where several high-flowing wells were gauged in past years.
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A group of independents is to drill a wildcat west of the Ouachita thrust belt in central Texas east of an area where several high-flowing wells were gauged in past years.

Rodessa Operating Co., Tyler, Tex., is to operate the 9,000-ft test 3 miles south of Tolar in lightly-drilled Hood County. This area is about 35 miles southwest of Fort Worth and just south of shallow Lipan gas field.

The 5,000-acre prospect is supported by several thousand acres of 3D seismic data, said consulting geophysicist Michael Hanratty.

The well is to spud in late April or May. The 9,000-ft mark is thought deep enough to intersect two main objectives: an upper reef zone and a deeper fracture zone. A third target would require a well to perhaps 18,000 ft.

Dennis S. McMurdie, a Salt Lake City geologist, has contributed geologic work to the prospect. McMurdie has published the theory of thick, subthrust Paleozoic sediments in central Texas (OGJ, Jan. 30, 1989, p. 86).

Following the Ouachitas

The well site is about 40 miles east of geologically-interesting wells drilled in the 1980s and early 1990s in Eastland County.

Most prominent among them is the Ray Richey & Co. 3B Ora Jones, which blew out at 3,378 ft in November 1985. It produced 700,000 bbl of oil and 1 bcf of gas in 90 days from what was believed to be a reef of Mississippian Chappel age.

About 1.5 miles southwest of that well, the Petroil 1 Fox-Inland went to TD 8,500 ft in 1989. It flared gas but was later abandoned.

Fina Oil & Chemical Co. had a program on acreage formerly held by a predecessor of Magnum Hunter Exploration Inc., Dallas. Two wells were drilled in 1992-93. The 1 Hightower Deep went to TD 5,800 ft, and 1 Lake Leon Deep went to 9,845 ft. Both were abandoned.

Several other high-rate producing wells have been completed along the western edge of the thrust belt from Eastland and Jack counties to as far north as Carter County, Okla. These wells are aligned along the frontal edge of the projected thrust fracture zone, with associated transcurrent offsetting faults, said newly-formed International Oil & Gas Inc., Dallas, which is spearheading the project.

The participants hope the new Hood County well will reach rocks of Cambro-Ordovician (Ellenburger) age so it can test a postulated extensive, fracture-fed Chappel reef. Future wells on the prospect could test the deeper suspected Mississippian-aged subthrust.

Costs to 9,000 ft are estimated at $335,000 turnkey for a dry hole and a further $247,000 for completion.