The LNG would be shipped directly from the North Slope via ice breaking LNG tankers.

Initially, the project will take natural gas at "sufficient volume to export at least 4 million tons per year of LNG," Qilak President David Clarke told Petroleum News.

"The agreement at the moment is exclusively with ExxonMobil; once we're able to talk to Hilcorp, once they take over the BP interests, then we hope to have enough gas to increase that to at least 6 million tons," Clarke said.

Hilcorp is slated to purchase the 32% share of Point Thomson currently owned by BP, under a $5.6 billion sale of BP's North Slope assets and operations announced in September.

If all goes well, first gas would ship in 2025 or 2026, Clarke said. A feasibility study will begin in 2020.

The LNG tankers, designed in Finland, are double acting ships with an efficient bow for open water and thin ice cover, and a heavy ice breaking stern. The ship is run in reverse in heavy ice. The design has better open water performance than traditional ice breaking ships.

Similar vessels have been successfully employed to carry LNG from the Yamal LNG plant located in Sabetta on the Yamal Peninsula, in Arctic Russia.

"The company that designed them has come up with a Mark II version that we would use, very similar but improved performance and LNG capacity," Clarke said.

The LNG plant will be a gravity based structure, which will be floated into place and ballasted down on the seabed.

"Basically, its weight is what keeps it in position," Clarke said, adding that the structure has LNG storage in its base, the liquefaction plant on the top deck, and offloading arms to load the ships.

It is yet to be determined if the LNG plant will be in state or federal waters. It must be far enough offshore to have sufficient depth for year round operations of the LNG tankers.

The gas pipeline from Point Thomson will be trenched and buried to avoid ice scour, Clarke said.

A gas treatment plant would be located onshore at Point Thomson.

"It's more efficient to do that from a process perspective; then ExxonMobil is responsible for disposing of the CO2 and H2S," Clarke said. "It would be what is called pipeline quality gas; it would have the contaminants removed, it would be dry, and we would be able to liquefy 100% of that gas."

"We're looking to use a similar type design for Prudhoe Bay in the next phase, and a similar design might work in the Mackenzie Delta in Canada," Clarke said. "The concept is to design one and build many. It just makes the whole project more manageable; it's easier to finance; it's easier to match the supply of LNG to the demand in Asia."

- STEVE SUTHERLIN

See story in Oct. 27 issue, available Friday, Oct. 25 at www.PetroleumNews.com.