Operators are establishing oil and gas production in the large, less-explored area between Utah's giant Altamont-Bluebell and Monument Butte fields.
The initial work indicates substantial shallow oil and deeper gas potential in this part of the Uinta basin.
Harvest Natural Resources Inc., Houston, said it appears to have made a commercial oil discovery south of Altamont-Bluebell and added $13.5 million to drill five wells nearby in Duchesne County.
The Harvest Bar F 1-20-3-2 discovery well, in 20-3s-2w, stabilized at 900 b/d of 42° gravity yellow wax crude and 650 Mcfd of gas at 1,400 psi flowing surface pressure from six commingled intervals in Lower Green River and Upper Wasatch at 8,200-9,600 ft.
The company hydraulically fractured the six intervals, which yielded more than 4,000 bbl of oil in the first 5 days of production while still cleaning up. Tests are to continue for 1-2 weeks, and production will start as soon as tanks and a gas flowline can be built.
Deeper gas potential
Branta Exploration & Production LLC, The Woodlands, Tex., another participant, noted that the Bar F well went to a total depth of 17,566 ft and also appears to have established the presence of a multitrillion cubic feet, long-term gas resource that could be held by production from developing the shallower oil formations.
Bar F flowed at rates of 1.5 to 2 MMcfd from various individually tested intervals in basin centered, overpressured Mesaverde tight sands at 14,000-17,400 ft after an eight-stage hydraulic frac program. The tests didn't conclusively determine commercial potential in Mesaverde, Branta said.
"The Bar F established the fundamentals for long-term natural gas drilling including an interval of 3,000 gross ft of tight sands with natural gas, overpressure, evidence of natural fracturing, and confirmation of the utility of hydraulic fracing," Branta said. Branta has interests in more than 64,000 gross acres in the Antelope gas resource.
Branta said the Bar F well is 7 miles south of Altamont-Bluebell field and that another operator has recently completed two other southerly extension wells northeast of Bar F.
Altamont-Bluebell has produced more than 373 million boe from 792 wells.
Harvest said the well's results indicate that much of its 65,000 gross acres (39,000 net acres) in the basin is prospective for appraisal and potential development targeting the intervals tested in the Bar F well. Branta has interests in more than 90,000 gross acres in the southerly extension area and plans to drill four delineation wells this year.
Monument Butte extension
Branta also said it has participated since December 2009 in eight oil wells known as the Moon wells in the South Myton Bench extension area of Greater Monument Butte oil field, including some of the highest initial producing rate wells drilled to date in the field.
Six of the wells have combined output of more than 115,000 bbl of oil since December 2009, and two are shut in until processing facilities are expanded. The Moon 3A-29 well is making 350 b/d after an initial flow of more than 1,900 b/d.
Outside of South Myton Bench, several wells drilled by other operators to delineate the Monument Butte north extension area are capable of producing at rates in excess of 100 b/d. One well 14 miles northeast of the Moon wells produced at 100 b/d, and another well 11 miles to the west made 400 b/d.
Branta has interests in 24,000 gross acres in the Monument Butte northerly extension area and plans to drill 5 to 10 development and stepout wells in 2010.
Harvest also approved $2.6 million to drill five more appraisal and development wells targeting Green River oil on the southern part of its Antelope land position in Duchesne County near Monument Butte field. The drilling will occur on land adjacent to a successful eight-well drilling program carried out in late 2009 and early 2010.
Greater Monument Butte field, discovered in 1964, and has produced about 68 million boe from more than 1,600 wells.
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