On Nov. 1 the Alaska Department of Natural Resources' Division of Oil and Gas approved the formation of the Narwhal unit by joint venture partners Narwhal LLC and EE Partners Corp., which each hold a block of leases in the unit.
(See map in the online issue PDF)
In state of Alaska submerged lands of West Harrison Bay offshore the National Petroleum Reserve-Alaska, the Narwhal unit encompasses approximately 77,848.60 acres and encircles Shell Offshore's recently relinquished 88,000-acre West Harrison Bay unit.
The Narwhal unit area is on trend with published maps of Nanushuk topset trends that connect to existing discoveries.
Exploration plans
EE Partners submitted a unit plan of exploration, or POE, as part of the application, and met with the division for a technical presentation in August.
In the POE, EE Partners outlines a comprehensive five-year plan.
For the years 2024 and 2025, Narwhal commits to several non-drilling initiatives, including completing and filing critical path permits, evaluating drilling rig options, continuing the comprehensive geological and geophysical technical assessment for selecting a drilling location, conducting marine and shallow hazard surveys, reprocessing 3D seismic data for higher resolution imaging of shallow sediments, contract for field equipment and services, and commence mobilization of equipment and personnel related to winter 2025-26 drilling.
In 2026, EE Partners commits to drilling two exploration wells to evaluate the Nanushuk formation. Pending ongoing analysis of geophysical data, one of the exploration wells may be drilled deeper to evaluate the Torok.
Based on the results of these initial wells, EE Partners plans to complete two additional exploration wells in 2027, continuing the evaluation of the Nanushuk and possibly the Torok formation, acquiring additional 3D seismic as needed.
In 2028, EE Partners will analyze the results of the two additional wells and submit the initial plan of development, or POD, for the Narwhal unit.
As part of the division's approval of the Narwhal unit formation, the division is requiring EE Partners to post a performance bond to DNR in the amount of $750,000 if an exploration well is not completed by July 1, 2026. This bond must be posted no later than July 31, 2026.
If EE Partners does not complete an exploration well by Dec. 31, 2028, the bond amount will increase to $1.5 million which must be posted no later than Jan. 31, 2029. Moreover, the Narwhal unit will automatically terminate five years from its effective date.
However, the bond will be returned upon EE Partners' completion of an exploration well.
The division approved the proposed POE, which is effective Nov. 4, 2024, through Nov. 4, 2029.
A second POE is due 90 days before the expiration of the first POE on Aug. 6, 2029.
Lease acquisitions
In the 2016 Beaufort Sea Areawide Lease Sale, Narwhal acquired six leases comprising 31,214.80 acres. Narwhal then acquired seven additional West Harrison Bay leases totaling 28,899.36 acres in the 2019 Beaufort Sea Areawide Lease Sale.
Narwhal's combined current leasehold is 57,950.34 acres.
EE Partners was the high bidder on seven Beaufort Sea leases in the 2023 Beaufort Sea Areawide Lease Sale. These leases comprise 23,370 acres.
The EE Partners leases in West Harrison Bay area are adjacent on one end to the Narwhal LLC leases and on-trend with the Narwhal leases' potential hydrocarbon accumulation, Narwhal/EE Partners said in their unit application.
EE Partners was the largest participant in the 2023 Beaufort Sea Areawide Lease Sale, and the only company to acquire leases in Harrison Bay.
The applicants have invested more than $6.8 million in the Narwhal unit leases.
All or part of reservoirs
"A unit must encompass the minimum area required to include all or part of one or more oil or gas reservoirs, or all or part of one or more potential hydrocarbon accumulations," the division said in its approval.
The agency noted that EE Partners had submitted confidential geological, geophysical and engineering data that demonstrated the area approved for the Narwhal unit includes all or part of an oil reservoir and potential hydrocarbon accumulations.
Available seismic
Two 3D seismic datasets cover portions of the unit area, both of which are available publicly for a cost through the state of Alaska Geologic Material Center. The "Harrison Bay 3D (Conoco)" seismic dataset was acquired in 2004 and covers most of the southern portion of the unit area.
The "Harrison Bay 3D (FEX)" seismic dataset was acquired in 2006 and covers an area south and west of the northern portion of the unit area. Although this particular 3D dataset covers little of the unit area, it is helpful for mapping clinoform trends into the area, the division said.
Multiple 2D seismic lines also are available in the West Harrison Bay area. The 2D seismic lines, collected during the initial exploration of the National Petroleum Reserve in Alaska, or NPRA, allow for mapping the stratigraphic architecture of the area.
As part of the Narwhal unit application, Narwhal submitted mapped surfaces over the available 2D and 3D seismic, as well as the seismic to well tie from the Atigaru Pt. No. 1 well.
Nearby wells
To date, no wells have been drilled within the Narwhal unit, although several legacy exploration wells have been drilled nearby, the most recent having been drilled in 1986.
None of these wells claimed discoveries in either the Nanushuk or Torok formations. The division said "this is possibly because the reservoirs in these formations often consist of thin bedded pay that can require specialized petrophysical techniques to accurately describe pay from log data, as well as fracture stimulation in order to flow. As a result, they were often overlooked in the early exploration wells."
The outer continental shelf Mars No. 1 well, approximately 7 miles north of the Narwhal unit, was drilled by Amoco Production Co. in 1986. It targeted the Ivishak and Lisburne formations. Sidewall cores were taken over the Ivishak and Lisburne and a drill stem test in the Ivishak produced only a trace of oil with water.
The well was determined to be non-producible. The well report indicated that sandstones in the Nanushuk/Torok were thin and high in silt and clay content. While there were no oil shows recorded on the mud log, several intervals in the Nanushuk/Torok displayed increased gas on the chromatograph and the lithology column indicated oil was observed in returns over the shakers.
The N. Kalikpik Test Well, approximately 30 miles west of the Narwhal unit, was drilled in 1982 by Husky Oil, targeting a seismic amplitude anomaly that had been interpreted as possible Kuparuk River sandstone. There were no Kuparuk sands present in the test well. Very minor gas shows were observed across the Nanushuk and Torok formations, and several very poor oil shows were observed in the same formations but were interpreted to be dead oil or organic matter.
The Cape Halkett No. 1 well, about 9 miles northwest of the Narwhal unit, was drilled in 1975 by the U.S. Navy. Sidewall cores were gathered over most intervals. Poor gas shows were observed in the Torok formation, but no other indication of hydrocarbon was seen in the Nanushuk or Torok formations.
The Atigaru Pt. No. 1 well, which lies less than a mile outside the Narwhal unit, was drilled in 1977 by Husky Oil. It targeted the Lisburne Group carbonates and the Sadlerochit Group sandstones with secondary targets in the Kuparuk formation and the Sag River sandstone. Both the Lisburne and Sadlerochit formations showed no porosity development, the Kuparuk formation was not developed at this location and the Sag River sandstone was found to be wet. At the time, the well was deemed unworthy of further evaluation. However, oil shows were encountered in "thin, shaly, and very tight" sandstones of the Nanushuk and Torok formations.
2,000 feet thick
The S. Harrison Bay No. 1 well, less than 2 miles south of the Narwhal unit, was drilled in 1968 by Husky. It primarily targeted the Sadlerochit and Lisburne groups with secondary targets in the Torok formation, the Kingak formation and the Sag River sandstone. The Nanushuk Group, which was expected to be very thin, was found to be 2,000 feet thick. Hydrocarbon shows were observed in sandstones of both the Nanushuk and Torok.
Two drill stem tests were attempted over sandstones in the Torok that exhibited good fluorescence and yet these tests were negative.
The W. T. Foran No. 1 well, 7 miles northwest of the unit, was drilled in 1977 by Husky. It targeted the Sadlerochit Group sandstones and Lisburne Group carbonates, with the Kuparuk sandstone as a secondary target. All the targets had good reservoir characteristics and oil staining or shows but drill stem tests revealed that all three were water wet and that hydrocarbons had been flushed away from the area.
The Nanushuk in this well was described as tight and there were no hydrocarbon shows. Minor gas shows were recorded over fine grained sandstones in the Torok formation.
The Livehorse 1 well, drilled in 1982 by Chevron, has a surface location on the same pad as the W. T. Foran No. 1 well. The data from this well is held confidential indefinitely.
Nanushuk fairways
Development of multiple Nanushuk fairways is occurring across the North Slope and the Nanushuk continues to be an exploration target for multiple operators.
Production is ongoing from the Nanushuk formation by ConocoPhillips at the Qannik Participating Area of the Colville River unit and the Narwhal PA of the Colville River unit.
ConocoPhillips recently applied to the Alaska Oil and Gas Conservation Commission for pool rules and a pilot enhanced oil recovery project for the Minke oil pool, another Nanushuk reservoir within the Colville River unit.
Additionally, ConocoPhillips is producing from the Nanushuk in the Kuparuk River unit and applied for the formation of the Coyote PA in 2024.
ConocoPhillips is also advancing the Willow project in NPRA, which also targets the Nanushuk formation.
Santos subsidiary Oil Search is actively developing the Nanushuk reservoir in the Pikka unit and has plans to develop it in the Quokka and Horseshoe units. Oil Search recently reported that Pikka Phase 1 is 60% complete with first oil expected in the first half of 2026.
Oil Search has stated that the Quokka and Horseshoe units will be developed sometime after Pikka Phase 1 starts up.
Conclusion
In Its conclusion on unit application approval, the division said, "sufficient evidence has been provided for a possible reservoir and hydrocarbon presence in the area to merit designation as a potential hydrocarbon accumulation, and thus unit formation."
Exploration drilling and fracture stimulated well tests, however, are required in the Narwhal unit "before it will be clear that this is a viable development," the division said in its approval.
The approval was signed by division Director Derek Nottingham.
