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Unocal looking at pod style drilling for coalbed gas prospect Plan of exploration for Pioneer unit updated, but negotiations under way with experienced developer; company tells state plans may change Kristen Nelson PNA News Editor
Unocal Alaska Resources has submitted an annual update of the plan of exploration for its 72,000 acre coalbed gas Pioneer unit between Wasilla and Houston.
The company has also told the state that it is negotiating with a third party with extensive coalbed gas development experience and may alter the exploration plan and cluster wells into pods to accelerate de-watering and determination of commercial viability.
Unocal said it might be proposing amendments to the plan, such as temporarily deferring drilling in one of three areas in the unit and doing pod-style cluster wells in two areas.
A pre-pilot phase, described by Unocal in December 1997, included three exploration wells to minimum depths of 2,500 feet, one in each of three areas of the unit, with coal seams to be cored in at least two wells and measurements of gas yield, absorption, cleat density and permeabilities.
Fracture stimulations and production tests would be attempted in at least two wells, Unocal said. BLT No. 1 will be stimulated and tested Unocal also plans to reenter and stimulate selected intervals on the BLT No. 1 well drilled by ARCO Alaska Inc. in 1992 near Big Lake on the western edge of the unit.
The 1999 plan update indicates that drilling would begin by May 1 with one rig and up to a month of drilling planned for each well.
A disposal well will be drilled and then the exploration wells, which will target coalbed gas reservoirs that range from 1,000 feet to 4,500 feet deep. Cuttings from the drilling will be used at the Pioneer No. 1 well “to construct a cement pad for a staging area (via cementation or fixation of the cuttings),” Unocal said, following approval from approval from the land owner and from the Alaska Department of Environmental Conservation.
The wells presently planned will be drilled from privately held surface land.
While drilling should be completed in 120 days, Unocal said, testing of the coalbed gas wells will take up to 18 months. Water needs to be removed from coalbed gas wells so the gas can be produced.
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