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New Colville River pool
Minke, a Nanushuk oil reservoir, will be developed from existing CD5 drill site
Kristen Nelson Petroleum News
ConocoPhillips Alaska applied to the Alaska Oil and Gas Conservation Commission Sept. 25 for pool rules and a pilot enhanced oil recovery project for the Minke oil pool at the Colville River unit.
The company requested that the Minke oil pool be defined as the interval between measured depths of 5,222 feet and 6,433 feet in the CD5-22 well, with the base of the pool the top of the Torok formation and the top of the Minke pool as the top of the Minke formation. Minke, on the western edge of the Colville River unit, is part of the Brookian Nanushuk formation, ConocoPhillips said.
Minke has been penetrated since the late 1990s by wells drilling to deeper targets, but "was historically overlooked due to its subtle petrophysical response (driven by thin-bed suppression) along with variable fluid signatures" and first flow tested just this year in the CD5-32X, the company said. Following positive results from the CD5-32X, plans were developed for the first horizontal producer/injector well pair, to be drilled in 2024-25, with the goal of demonstrating "production from, and injection into, the Minke reservoir."
The reservoir ConocoPhillips said the Minke reservoir is at the eastern section of the Nanushuk formation and the western edge of the Colville River unit. The reservoir is a combination structural-stratigraphic trap. The primary target is the upper 100 feet of the interval.
"Unlike more typical multi-zone or multi-layer fields on the North Slope, the Minke Oil Pool represents a single hydrocarbon accumulation based on current data," the company said.
The original oil in place estimate for Minke is from 80 million to 150 million stock tank barrels for the area planned for development from CD5.
Development will be phased, with an estimated nine "horizontal multi-stage fracture stimulated producers" and eight "multi-staged fracture stimulated injectors," with plans to be refined based on long-term production and injection data from the first producer and injector.
The wells will have from 4,000 to 10,000 feet within the reservoir.
Recovery ConocoPhillips said the fluid quality of the oil pool requires secondary recovery for economic production, with water injection, the main recovery process at Colville River, planned for Minke.
Primary recovery is estimated at 5-10% of original oil in place, with an additional 15-25% from waterflood, for a total of 20-30%. Gas injection is being evaluated.
"The largest remaining uncertainty for the Minke development is the question of interconnectivity of the reservoir at the proposed development scale" which is 1,000 to 1,500 foot well spacing, the company said.
Facilities Initial development will be from the existing CD5 drill site, which delivers fluids to the Alpine Central Facility some 7 miles away.
Full production of Minke, while continuing production from existing CD5 pools, is expected to require infrastructure upgrades, with one of the earliest "likely to include a header expansion for additional surface well locations" along with an additional remote electrical and instrumentation module to accommodate additional surface well slots.
Injection water will be seawater, with the potential of produced water use in the future.
"The Minke trend extends outside the proposed Minke Oil Pool to both the southwest and the northeast," with the proposed pool "an area notionally developable from CD5. Future Minke Oil Pool expansion options are being evaluated," the company said.
Injection The initial injection order is for 3 years, which, the company said, allows time for drilling the first injector, test injection performance and analyzing results. The pilot project involves two offset injectors and one producer.
The request is for a pilot project as feasibility of water injection into Minke has not been established.
The first injector is planned to be drilled this December followed by injection in January, with timing for drilling of a second injector contingent on results from the first.
While CD5 is currently on sea water service, this could change, the company said, but over the past 10 years compatibility of both produced water and sea water with the Brookian age reservoirs has been demonstrated at the Alpine Central Facility.
Injection rates of between 2,000 and 8,000 barrels per day are planned for the pilot project.
The company said Minke extends for some 29 miles and has been penetrated by approximately 41 wells in the Colville River unit and three wells in the vicinity of the CRU and the Greater Mooses Tooth unit.
Ownership, regulatory issues Royalty owners are the Arctic Slope Regional Corp. and the U.S. Bureau of Land Management.
ConocoPhillips said a separate participating area is planned for Minke. (Participating areas are established by the Alaska Department of Natural Resources' Division of Oil and Gas.)
In a public notice posted Oct. 8, the commission said it would hold a public hearing on the matter Nov. 19 at 10 a.m. in its Anchorage offices, with audio call-in available at 907-202-7104 conference ID 349 722 430#.
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