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AOGCC approves changes to gas pool limits
Vertical extent of Tertiary System Gas Pool at North Cook Inlet Unit expanded; gas well spacing requirements within unit eliminated Kristen Nelson Petroleum News
The Alaska Oil and Gas Conservation Commission has approved a request by Hilcorp Alaska to expand the vertical extent of the North Cook Inlet Unit Tertiary System Gas Pool and to change well spacing requirements for wells within the gas pool.
Hilcorp requested the changes in late January and the commission held a hearing on the request March 17
Hilcorp acquired the NCIU from ConocoPhillips in 2016.
In an April 20 order, the commission approved the request to expand vertical extent of the Tertiary System Gas Pool and change well spacing requirements for gas pool wells.
The vertical limits of the Tertiary Systems Gas Pool had been defined as the interval correlated to the Pan American Petroleum Corp. North Cook Inlet State 17589 well No. 1 from 3,500 feet to 6,200 feet measured depth.
The new vertical pool definition requested by Hilcorp is from 3,943 feet to 8,608 feet measured depth in the North Cook Inlet A-15 well.
The North Cook Inlet unit lies offshore within Cook Inlet; all leases in the unit are held 100% by Hilcorp, the commission said in an April 20 decision.
Spacing change Hilcorp also requested a change in well spacing, which had been defined as a “cluster” spacing pattern. The company asked that the well spacing rule be changed to remove gas well spacing restrictions within the Tertiary Systems Gas Pool, except that no gas well would be completed less than 1,500 feet from an exterior unit property line where the owners and landowners are not the same on both sides of the line.
The commission said amending the pool rules was appropriate.
“Extending vertically the Tertiary System Gas Pool and revising well spacing requirements will facilitate further development drilling and ensure greater ultimate resource recovery, but will not promote waste, jeopardize correlative rights, or result in an increased risk of fluid movement into freshwater aquifers.”
Additional drilling In materials prepared for the commission hearing on the request Hilcorp said the initial field development plan assumptions included laterally continuous sands and depletion drive reservoir. It said remaining potential will come from completions to-date designed to deliver high rates of natural gas production to meet liquefied natural gas contracts (North Cook Inlet production went to the LNG plant at Nikiski until regular shipments ended in 2012, although there were spot cargoes in 2014 and 2015), variable water drive strength, by-passed pay and penetrations which missed the top of the structure.
The company included a list of planned drilling at the unit, including sidetracks from four existing gas wells, three currently in production and one suspended, and a new well described as a deep oil appraisal well.
An initial development plan for a known oil pool below the North Cook Inlet gas field was included in Hilcorp’s 2019 plan of development, filed with the Division of Oil and Gas last year (see story, “Another CI oil field?” in April 14, 2019, issue of Petroleum News). The company told the division it expected to drill the well in 2020 and said because it would penetrate the top of the structure of the Sterling and Beluga gas sands, the well would enable an evaluation of remaining dry gas.
There has been no oil production from the NCIU to data, although there has been an interest in oil in the area since ARCO Alaska drilled its Sunfish wells nearby in the early 1990s.
In its online description of the North Cook Inlet unit, the commission says all gas production is from the Sterling and Beluga formations. The four proposed gas sidetrack wells will all target the Sterling and Beluga sands, the company said.
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