Kuparuk Torok PA approved effective Oct. 22

Decision establishes Torok participating area within the Kuparuk River unit, but smaller than requested by ConocoPhillips Alaska

Kristen Nelson

Petroleum News

On Oct. 22 the state approved formation of the Torok participating area in the ConocoPhillips Alaska-operated Kuparuk River unit.

In its approval the Alaska Department of Natural Resources' Division of Oil and Gas said the area proposed by ConocoPhillips in its Aug. 31, 2023, PA application was some 19,178 acres, but the approved area is smaller, 16,102 acres, a 19.76% reduction. The reduction was based on "existing and future wells, their planned trajectories, and a 1,050 foot drainage radius around the outermost wells on the proposed well pattern," the division said, with quarter-quarter sections overlaid around the wells which determined a smaller area expected to be drained by the wells. The main difference between the company's proposal and what the division approved was the use by the division of quarter-quarter sections "whereas it appears the initial PA proposal was drawn on merely a quarter section outline approach where each quarter section was included if a well's drainage radius touched any part of a particular quarter section." The division said it also excluded the area in the southeastern corner where the 3S pad is located "since the location of surface equipment is not a factor considered when determining the size of a proposed PA, which is defined by reservoir and drainage extent."

STorok exploration

Sinclair Oil and Gas discovered Torok reservoir sands in the PA area in 1966 at Colville No. 1, the division said, and the area was further delineated by Texaco in the 1980s with Colville Delta 2 and 3.

The sands, "now called the Moraine reservoir" by ConocoPhillips were flow tested in Colville Delta 2 and 3, with Colville Delta 3 testing oil while Colville Delta 2 did not produce hydrocarbons to surface.

ARCO Alaska drilled further exploration and appraisal wells in the 1990s -- Kalubik 1, 2, 3 -- testing the extent of the reservoir.

"Although oil was tested and cores with excellent fluorescence were recovered from the Moraine reservoir interval, the high water cut of the vertical wells rendered the discovery uneconomic for development at the time," the division said.

There was a pause in activity from the mid-1990s to 2010, when "Pioneer successfully tested the concept of horizontal multi-stage frac (HMSF) wells in similarly deposited rocks within the same strata in the Oooguruk a few miles north of the planned Torok participation area," leading to further tests by Pioneer, Caelus and later ConocoPhillips. That work, the division said, resulted in additional core and log data being acquired and two additional test wells, 3S-19 and Nuna 1, within the proposed PA.

ConocoPhillips then drilled three producer/injector pairs, 3S Phase 1 (2015), Phase 2 (2018) and Phase 3 (2023).

The division said the three producer/injector pairs "continue to demonstrate favorable reservoir performance dating to first production in 2015 from HMSF injector/producer well pair."

In 2019 ConocoPhillips completed acquisition of the Nuna area from Caelus.

Moraine strata

The division said the phased approach allowed ConocoPhillips to apply learnings for proposed full field development and also took advantage of drilling technology advances, allowing for longer step outs an increased footage in the reservoir, enabling "full field development of this previously uneconomic resource."

In its 2024-25 Kuparuk plan of development, approved June 25 for Aug. 1 through July 31, 2025, ConocoPhillips committed to drilling eight wells in the proposed Torok PA area, the division said and a new drill site, 3T, will accommodate both Torok and Coyote (Nanushuk) development. Alaska Oil and Gas Conservation Commission production data show all Torok formation production to date is from 3S Pad.