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State approves Northeast West Sak PA
Kristen Nelson Petroleum News
The Alaska Division of Oil and Gas has approved a new participating area at Kuparuk, the Northeast West Sak PA.
In a May 29 decision the division said the new participating area includes portions of three state oil and gas leases within the Kuparuk River unit, some 2,688 acres. The NEWS PA includes acreage overlying the West Sak and Ugnu formations six miles northwest of the existing West Sak participating area.
The state approved formation of the West Sak PA in 1997 and expansions of that PA in 2004 and 2007.
The NEWS PA, however, is separate from the existing West Sak PA.
“Lack of communication between the NEWS PA and the WSPA warrants a separate participating area,” the division said.
Three wells completed ConocoPhillips Alaska, the Kuparuk River operator, has completed three wells in the proposed NEWS PA as unit tract operations and the division said confidential information submitted by ConocoPhillips indicates the West Sak reservoir within the NEWS PA is capable of producing or contributing to production in paying quantities.
Drilling is from drill site 3K and production will be processed through existing Kuparuk River unit facilities.
The NEWS PA is in the northeastern portion of the Kuparuk River unit and targets the West Sak sands, part of the West Sak-Schrader Bluff sands that occur throughout the Kuparuk, Milne Point, Prudhoe Bay and Nikaitchuq units.
“Individual sand bodies, separated by interbedded non-reservoir siltstones and mudstones, range from a few feet to about 40 feet in thickness,” the division said.
Alaska Oil and Gas Conservation Commission order 406 defines pool rules for West Sak, and the proposed NEWS PA lies within the West Sak oil pool boundary, the division said, with the stratigraphic limit of the pool defined as the equivalent of the interval between 3,742 feet and 4,156 feet measured depth in the 1971 ARCO West Sak No. 1.
Structural dip in east Kuparuk River unit West Sak sands have reservoir depths ranging from 2,700 feet true vertical depth in the southwestern portion of the unit to some 3,800 feet in the northeast.
The division said the eastward structural dip of the West Sak causes increasing reservoir temperatures in the east and an associated decrease in the viscosity of the oil. Reservoir temperatures range from 60 degrees Fahrenheit in the shallower western area to 80 degrees F in the deeper eastern area, while the API gravity of the oil varies between 10 degrees and 22 degrees and viscosity varies from about 30 centipoises to more than 300 centipoises.
ConocoPhillips has drilled one horizontal multilateral producer and two supporting multilateral injection wells since February 2008 targeting West Sak sands within the proposed NEWS PA. The production well, 3K-102, has averaged more than 1,200 barrels of oil per day. The division said ConocoPhillips plans to complete additional NEWS wells in 2010.
AOGCC data shows some 40.6 million barrels of oil have been produced from the West Sak formation at Kuparuk through March.
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