Hilcorp Alaska’s plan for developing the Liberty oil field in the Beaufort Sea is spelled out in the draft environmental impact statement that the Bureau of Ocean Energy Management issued on Aug. 17. The Liberty field is on the federal outer continental shelf, in Foggy Island Bay, about 15 miles east of Prudhoe Bay. The development plan proposed in the EIS involves the construction of an artificial gravel production island about five miles offshore and the laying of a buried subsea pipe-in-pipe pipeline to carry crude oil to shore. The pipeline would connect with the existing Badami pipeline for transporting the Liberty oil to the trans-Alaska pipeline.
The draft EIS, which contains a detailed evaluation of the potential environmental impacts of the development, is now entering a public comment period. BOEM requires comments on the document by Nov. 18 - public meetings have been scheduled for early October in Utqiagvik, Nuiqsut, Kaktovik, Fairbanks and Anchorage.
Field operator Hilcorp welcomed the publication of the draft EIS. The company said that the field holds an estimated 80 million to 150 million barrels of recoverable oil.
“Not only have similar proposals of the Liberty project been vetted and approved before, but gravel-based energy facilities have a proven record of safe operations, with some in production for over a decade in the Beaufort Sea,” said David Wilkins, Hilcorp senior vice president for Alaska. “We are eager to work with the communities across the North Slope and our partners throughout the state to develop a project that will greatly benefit Alaska and bring greater domestic energy security to the country.”
Discovered in 1980s
Shell Oil Co. discovered oil in the area of the Liberty field between 1982 and 1987, through the drilling of four wells into the Kekiktuk formation from two artificial gravel islands. The Kekiktuk is the reservoir rock for the Endicott oil field to the northwest. In 1997 BP confirmed the existence of the field through the drilling of the Liberty No. 1 exploration well.
In 1998 BP proposed developing the field from an artificial gravel island. However, in 2001 the company re-evaluated that plan and, in 2005, came up instead with a plan to develop the field using ultra-extended reach drilling from the satellite drilling island at the Endicott field. The company moved ahead with that plan, expanded the Endicott satellite island and installed a purpose-built drilling rig for the project. However, following technical problems and some issues relating to the Deepwater Horizon disaster, the company cancelled the project in 2012.
In 2014 BP sold 50 percent ownership of the field to Hilcorp. Hilcorp became field operator and has since moved ahead with planning the development of the field. And the plan encapsulated in the proposed action in the draft EIS is very similar to BP’s original 1998 concept.
Alternative options
The EIS does consider other options, including a couple of alternative possible locations for the production island, and the possibility installing field processing facilities on the Endicott satellite drilling island, rather than on the Liberty island. The EIS dismisses as technically infeasible the ultra-extended reach drilling option that BP had proposed in 2005. A “no action” alternative would eliminate the economic benefit to be gained from developing the field, the draft EIS says.
The Boulder Patch, a seabed feature of considerable environmental significance, played a role in assessing the potential environmental impacts of some options. Although the proposed plan places the artificial island outside the Boulder Patch, alternative island locations could move the island farther from the environmentally sensitive area. But these options would raise other issues. One option would place the subsea oil export pipeline in an area susceptible to seafloor scouring associated with the nearby Kadleroshilik River delta. Another option would require substantially longer well bores and, hence, a larger drilling rig and longer drilling times.
The draft EIS indicates that while the proposed action would likely have little impact on subsistence seal, waterfowl, goose and caribou hunting, noise from the Liberty development could have significant impacts on subsistence whaling in the nearby Cross Island area.
Development plan
The proposed option would place the 9.3-acre Liberty drilling and production island in about 19 feet of water, about five miles north of the Kadleroshilik River and 7.3 miles southeast of the Endicott satellite drilling island.
The island would have slots for five to eight production wells, four to six injection wells and up to two disposal wells. Infrastructure and facilities on the island would support oil production rates of some 60,000 to 70,000 barrels per day. Gas produced from the field would be used as fuel, for artificial lift from the production wells or for re-injection into the reservoir. Seawater, at some point co-mingled with produced water, would be injected into the reservoir for pressure maintenance. The buried subsea oil export pipeline would consist of a 12-inch oil line inside a 16-inch outer pipe. The subsea section of the line would be about 5.6 miles in length, while the onshore section to the tie-in with the Badami pipeline would extend for about 1.5 miles, the draft EIS says.
A mine site west of the Kadleroshilik River would act as source of gravel for the project.
Although Hilcorp is not yet in a position to determine when the Liberty development would start, or when to sanction the project, the draft EIS includes a potential schedule. The schedule indicates that first oil could start to flow toward the end of the third year or in the first few months of the fourth year of the development. The field has an expected life of about 20 years from first production, the draft EIS says.
Major construction of the island and its facilities, and the laying of the export pipeline, would take place in years two and three of the project, with development drilling potentially starting in year two and continuing through year four.
Four ice roads would potentially be needed to support the construction operation: one direct from Endicott to the Liberty Island, one from Endicott to the offshore pipeline route, one along the pipeline route, and an onshore ice road from the Endicott road to the pipeline tie-in on the Badami pipeline. Three ice pads would potentially support island, facility and pipeline construction.
Oil and gas potential
“The federal submerged lands of the Beaufort Sea are known to have great oil and gas potential,” said BOEM Acting Director Walter Cruikshank when announcing the publication of the draft EIS. “They also contain sensitive marine and coastal resources that Alaska Native communities depend on for subsistence. During this comment period we look forward to discussing this draft EIS with the Beaufort Sea coastal communities and getting meaningful feedback on ways it can be refined and enhanced.”
BP and Arctic Slope Regional Corp. are partnering with Hilcorp on the project.
“BP believes the Liberty project is important to Alaska’s economic future, and we support it moving forward in a manner that is respectful of the environment and of the local communities and their subsistence way of life,” said Janet Weiss, president of BP Exploration Alaska Inc.
“The Liberty Project represents the kind of development that Arctic Slope Regional Corp. has determined is important to our region and through local participation we can ensure that the needs and issues of our communities and shareholders are addressed,” said Richard Glenn, ASRC executive vice president of lands and natural resources.
