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Evergreen to drill new pilots Independent applies for four new Mat-Su coalbed methane wells this year Kristen Nelson Petroleum News Editor-in-Chief
Evergreen Resources Alaska plans to drill a four-well shallow coalbed methane pilot in the Matanuska Valley 30 miles north of Anchorage this year. This is in the same area where the company drilled two pilots last year, and it will also production test last year's and this year's pilots.
The company requested state approval for two new pilots, “to provide permitting, land management and operational flexibility,” but said it currently plans to drill only one of the pilots this year. Both are near Houston in the Matanuska-Susitna Borough and each includes four wells to be drilled no deeper than 3,750 feet. Work is expected to begin Aug. 1.
After the wells are drilled and completed, Evergreen told the Alaska Division of Oil and Gas in an operating plan, the wells may be production tested for as long as 10 months, with resulting gas vented or flared and the water trucked to an approved water disposal well.
Evergreen drilled two pilots in 2002, both in the Matanuska-Susitna Borough Pioneer unit which Evergreen purchased from Ocean Energy and Unocal in May 2001. The company said it received farmed-in shallow natural gas leases this May for areas adjacent to the Pioneer unit from the Houston area to near Moose Creek north of Palmer — generally north and east of the unit — and has applied for additional shallow natural gas leases adjacent to the farmed-in leases. The pilots proposed for drilling this year are on shallow gas leases north of the existing unit.
The 72,000-acre Pioneer unit was created by Unocal in 1997, and Evergreen said it has proposed expansion of the unit to include approximately 62,000 acres of shallow natural gas leases for a total of 134,000 acres of oil and gas leases and shallow natural gas leases.
Evergreen drilled pilot 1 and pilot 2 in 2002. The current operating plan is for pilot 4 and pilot 5.
Early this year Evergreen fracture stimulated a water disposal well, Pioneer 1702 15DA, drilled in 1999 by Ocean Energy, the unit's former operator. Evergreen also hooked up surface facilities for the water disposal well. The company is evaluating existing wells in the unit — the BLT No. 1 re-entry, the Pioneer 1702 15DD and the Pioneer 1702 14CC — for possible conversion to Class II water disposal wells and said it has cleared those well sites of accumulated trash and secured them with gates and fences. New work to begin in August Evergreen said its 2003-04 exploration program will include one production pilot, either pilot 4 or pilot 5, with four wells. Site preparation and construction of the 200-foot by 175-foot pad and access road are planned to begin in August. Drilling would occur in September, well completion in October and production testing November through August 2004.
Pilot 4 is in section 24 of township 18 north, range 3 west, Seward Meridian, 2.5 miles east of the main business district of the City of Houston. Access is from Armstrong Road off the Parks Highway, and an unimproved extension of road to the east. Evergreen said it would construct a new road off the unimproved road to provide access to the pilot location which is on state of Alaska and Matanuska-Susitna Borough surface estate and state subsurface.
Pilot 5 is approximately two miles northwest of pilot 4 in section 15-T18N-R3W, SM. It is also off Armstrong Road and Evergreen said a new road would be constructed along a section 22 center section unimproved road and trail. Surface and subsurface at pilot 5 are both owned by the state and Evergreen said it is in the process of initiating use agreements with owners of private lands whose property is skirted by or crossed by the proposed access road. One well would be cored In the pilot 4 area Evergreen said it would core one of the four wells “to ascertain reservoir properties of the producing coals and their adjacent formations.” Drilling for non-cored wells is estimated to take three and a half days; drilling time for the cored well is estimated at four and a half days. Evergreen said the estimates include mobilization and demobilization, well logging, running casing and cementing both surface and production casings. The company expects drilling operations, which will run 24 hours a day, to take a total of 30 days.
Completing the wells, including running cement bond logs, remedial cementing if required, perforating, hydraulic fracturing and cleaning up the wells after fracturing treatment is estimated at two to four days per well, and wells may need one to two weeks for the cement to cure.
Production testing, estimated to begin in mid-November, includes installation of all production equipment — tanks, down-hole pumps and measuring equipment — and placing wells on production. Water, gas rates and pressure will be measured. Installation of equipment averages four days, the company said.
Evergreen said it will most likely core the center well. The company drills pilots with a central well and three wells offset some 1,000 feet to the north, southeast and southwest of the central well.
The company told the state that the pilots are an exploration program “designed to test the coal's ability to produce natural gas.” The exploration pilot wells are drilled closer together than production wells would be.
“The pilot drilling and testing program is designed to provide information that will be used in the economic evaluation of developing this natural gas resource,” the company said. De-watering Coalbed methane wells require substantial de-watering before gas begins to flow from the coalbeds, Evergreen said. At Pioneer, and in adjacent proposed development areas, de-watering has not occurred. Wells in these areas, the company said, will behave “more like water wells and produce little or no gas.” To manage any gas that may be produced, the company said, it will use a diverter, check valves in the drill string and have a cement truck parked on location in case well-control issues occur.
At completion, after perforation of the casing, coal intervals will be hydraulically fracture stimulated. Evergreen said several hundred thousand pounds of sand will be pumped into each well and resulting fractures may extend from a hundred to several hundred feet laterally.
Production testing is scheduled to run for 10 months with a progressive cavity pump producing water from the coal seams. The pump will be propane-powered until natural gas is available from the well to provide fuel. A six-foot by eight-foot shed will be placed over the motor.
“Gas produced during this test will be vented/flared or used at the well site,” Evergreen said. Use at the well site would be to power equipment; the remaining gas would be vented or flared.
Water, then gas Evergreen said it may take up to several months before any natural gas is produced.
“Initially, only water and no gas will be produced,” the company said. Methane production will increase during initial stages of production, and then decline. Water production will decrease over time.
Evergreen told the state that this is an exploration program and it does not know what the magnitude of water or natural gas production will be.
“Indeed, the goal of this production test is to characterize the producibility of the Tyonek Coals,” the company said.
Occasional work-over operations may be required during the 10-month test period, Evergreen said. It may also have to re-fracture.
The company said it plans to “continue production testing and monitoring of the existing two pilots and the new pilot” until August of next year when it will submit a new plan of operations. Company using own equipment Evergreen said it would use its own drilling, cementing, hydraulic fracturing and work-over equipment, “built specifically for coalbed methane operations.”
The company said it uses primarily air to drill the wells in its exploration program. “Air is preferred because of its lower impact on the environment and because air is less damaging to the coals,” Evergreen said.
The company said none of the specialized drilling, cementing or completion equipment for coalbed methane development exists in Alaska, so “Evergreen will continue to utilize its own equipment and, for the most part, its own personnel” in the drilling operations.
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