Commission issues Oooguruk pool rules

Production will be from shallower Oooguruk-Kuparuk, Oooguruk-Nuiqsut pools; 49-110 million barrels of combined recovery expected

Kristen Nelson

Petroleum News

Pioneer Natural Resources Alaska received pool rules approval for its Oooguruk development off Alaska’s North Slope from the Alaska Oil and Gas Conservation Commission March 25. Pioneer, with a 70 percent interest, is the Oooguruk operator; Eni Petroleum US LLC holds the remaining 30 percent interest.

There are two pools, the shallower Oooguruk-Kuparuk and the Oooguruk-Nuiqsut.

The commission said Oooguruk-Kuparuk original oil in place is estimated at from 15 million to 25 million barrels, with primary recovery in the 6 to 10 percent range (1-2.5 million barrels) and recovery with waterflood expected to be between 26 and 34 percent of original oil in place, some 4 million to 8.5 million barrels.

In the Oooguruk-Nuiqsut, original oil in place is estimated at 250 million to 300 million barrels, with a 4-10 percent primary recovery rate expected, rising to 16-30 percent for primary plus waterflood and to 18-34 percent with primary, waterflood and under-saturated water-alternating-gas recovery, for an expected recovery of 45 million to 102 million barrels.

Oooguruk-Kuparuk production is expected to peak at between 2,000 and 8,000 barrels of oil per day, with annualized waterflood injection rates peaking at between 3,000 and 12,000 barrels of water per day.

Production from the larger Oooguruk-Nuiqsut is expected to peak at between 9,000 and 20,000 bpd, with annualized waterflood injection rates peaking at between 15,000 and 30,000 bpd. The miscible hydrocarbon gas injection rates are expected to peak at between 3 million and 20 million standard cubic feet per day.

Development drilling has begun

Facilities have been put in place and development drilling began at Oooguruk last year. The company said in December that 15 wells would be drilled in 2008, including disposal, injection and production wells.

First oil sales from Oooguruk are expected by mid-year.

Pioneer told the commission it plans to develop the pools separately without subsurface commingling.

The Oooguruk-Kuparuk pool will be developed with five to eight horizontal wells, about half producers and half injectors, each with 3,000 to 5,000 feet within the pool.

Pioneer asked for and received an exemption to well spacing restrictions for the Oooguruk-Kuparuk. Correlative rights are protected by a 500-foot setback from external property lines where the owners and landowners are not the same on both sides of the line, the commission said.

There will be 30 to 39 horizontal wells in the Oooguruk-Nuiqsut pool, also about half producers and half injectors, but in the Oooguruk-Nuiqsut up to 9,000 feet of the wells, undulating horizontals, will be within the pool.

Water injection will begin within a few months after production startup at the Oooguruk-Kuparuk.

The Oooguruk-Nuiqsut will ultimately be developed as an under-saturated water-alternating-gas enhanced oil recovery project, with cyclic injection of immiscible gas and water used to enhance recovery.

“Laboratory results suggest that when gas contacts the under-saturated Nuiqsut oil, the oil swells, its in-situ viscosity lowers, and waterflood recovery should improve,” the commission said.

Waterflood at the Oooguruk-Nuiqsut is planned to begin this June.