Depending on results of exploratory drilling in 1996, the Colville Delta about 20 miles west of Kuparuk River oil field could be the site of the next large oil development on Alaska's North Slope.
Although additional success in the coming winter drilling season is deemed necessary to justify commercial development, Arco Alaska Inc. and its partners, Union Texas Petroleum Alaska and Anadarko Petroleum Corp., have begun work to reduce drilling and field development costs. Arco owns 56% working interest in the Colville project, with Union Texas and Anadarko each owning 22%.
Arco has initiated advance work on engineering design and permitting so the partnership can get an early start on development if the 1996 exploratory program is successful. Groundwork is being laid in an attempt to shorten the 5-7 years that can be required between discovery and commercial production in Alaska's remote locations.
The approach is a new one, designed to speed up commercial development if the go-ahead comes after next year's drilling season. In the past, prospects would be proved before permitting began. Arco, Union Texas, and Anadarko agreed early discussions would allow them to better address state agency issues and concerns and comply with state and federal environmental regulations.
Concept outlined
In briefings conducted by Arco for the Alaska Department of Natural Resources and other government regulators, the various agencies have been given a view of the potential development that could occur if the 1996 exploratory program is successful.
During meetings, the partners shared the initial concept for project development, including a possible base camp location, pipeline routes, and drillsites. A conceptual engineering study is being made which, if the field is declared commercial, will be used in the permitting process.
At least six wildcats scattered over a large area in the Colville River delta have been tested at high rates. Three drilled by Texaco and one by Amerada Hess prior to Arco taking over operational reins in 1991 flowed at rates up to 1,000 b/d, but none was regarded as sufficient for a stand-alone development.
Arco in 1992 drilled the 1 Fiord, in 2-12n-5e, and the 1 Kalubik, in 11-13n-7e. The Fiord well flowed oil from one interval at a rate of 1,065 b/d and from another, after hydraulic fracturing, at a rate of 180 b/d. The Kalubik well flowed at a rate of 1,200 b/d from one interval and from another, after hydraulic fracturing, at a rate of 410 b/d.
Arco drilled three more wells in winter 1993, two in winter 1994, and two, each with sidetracks, this winter. Results have not been released.
After this year's program, reserves found to date were estimated at 100 million bbl.
"We believe reserves exceeding this level could be found by future drilling," a Union Texas spokesman said.
The wildcats drilled this winter were 1 Alpine, in 1-11n-4e, about 7 miles southwest of the 1 Fiord 1992 discovery; and the 3 Fiord, in 25-12n-5e, about 4 miles southeast of the 1 Fiord.
The 1 Alpine was a vertical hole that went to TD 7,500 ft. The first sidetrack, 1A Alpine, went to TD 9,940 ft, at which point true vertical depth was 7,343 ft. The sidetrack hole bottomed about 5,600 ft northwest of the surface location. The second sidetrack, 1B Alpine, went to an undisclosed depth. The permit called for the sidetrack hole to bottom about 3,900 ft southeast of the surface location.
The 3 Fiord was a vertical hole the first time down, bottoming at 7,030 ft. The sidetrack, 3A Fiord, went to TD 9,147 ft (7,038 ft TVD). The well bottomed about 4,900 ft south and slightly west of the surface location.
Depending on weather, the 1996 winter drilling season will start about February and run through early April. Ice roads will be required to allow movement of equipment to drill sites. It will be necessary to move out equipment before ice begins to thaw in May.