Castberg downsizing pays off

Oct. 14, 2016
Aker Solutions and Statoil are working to bring down costs of the Johan Castberg project in the Barents Sea by NOK40-50 billion ($4.8-6 billion).
Jeremy Beckman • London

Aker Solutions and Statoil are working to bring down costs of the Johan Castberg project in the Barents Sea by NOK40-50 billion ($4.8-6 billion). Statoil decided to take action two years ago when projections for its original development plan forecast a breakeven price of $90/bbl, based on a scenario of a floating production platform with an export to a new storage terminal in northern Norway.

The company and its partners agreed to scale back the scope, focusing instead on an FPSO with subsea completions. At ONS 2016 in Stavanger, Aker Solutions’ regional manager Nils Olav Solheim outlined some of the solutions his company had devised with Statoil over the past two years to make costs more manageable.

Johan Castberg comprises the Skrugard, Havis and Drivis discoveries, 240 km (149 mi) northwest of Hammerfest in a water depth of around 370 m (1,214 ft). The location is north of Alaska: in some ways conditions are less harsh than in the Norwegian Sea to the south, Solheim said, although the design temperature is 5°C (23°F) lower than in the Haltenbanken region, so a greater degree of winterization measures are needed. The lifeboats are being designed to protect against atmospheric icing, and infra-red heating is an option to protect the release mechanism. The helideck too will be supplied with water-borne heat if icing prevents landings.

The scaled-back FPSO is now 295 m (968 ft) long and comprises a 57,000-metric ton (62,832-ton) hull and living quarters supporting an 18,000-metric ton (19,841-ton) topsides. All aspects of the structure and the processes used onboard have been reviewed, with certain items of equipment removed if deemed not entirely necessary. For instance, Statoil’s initial plan had been for three-stage separation, but the review process determined that one stage could be taken out. “We also decided to remove the originally planned multiphase meters,” Solheim said, “realizing that we could manage with a test separator.” The living quarters and cabins have been re-sized to reflect the fact that peak manning – around 40 people – will only be needed for a two-three week maintenance period every three or four years.

The 7,000-metric ton (7,716-ton) turret is located more forward than on other FPSOs to ensure weathervaning in the event of a power loss onboard, Solheim explained, so that the vessel is always lined up in the same direction as the wind. This also ensures that any gas leak is vented in a safe direction. Statoil has re-designed the wells and subsea facilities, he added, with fewer templates and flowlines and a lower number of risers connecting to the turret – part of the turret has also been slimmed down to achieve a more cost-effective solution for the basic needs of receiving incoming hydrocarbons and injecting gas and water to drive out oil from the reservoirs. All produced water and a certain amount of seawater will be needed to sustain production levels. One benefit of keeping equipment needs to an absolute minimum is that the deck will have ample free space, Solheim added, allowing for installation of extra modules for any future field tie-ins.

Pre-front-end engineering and design (FEED) is due to be completed this month. Aker Solutions has options under its contract to also bid for the subsequent full FEED and detailed design studies. If all goes to plan, Castberg could come onstream during 2022.

Statoil widens hunt in Barents Sea

Statoil will target different frontier plays away from the Castberg area in its next wave of Barents Sea wells, said head of exploration Jez Averty during another ONS briefing. The company plans to drill 17 exploratory wells offshore Norway between now and the end of next year, he said, including seven in the far north. Of these five will likely be on prospects in previously undrilled frontier plays. Even if one of the wells provides a major discovery, the company will stick to its schedule, returning to appraise at a later date. Higher-risk targets include the Koigen Central structure on the Stappen High, and Korpfjell on the recently awarded P1859 license, which will be Norway’s most northerly well to date and a “true wildcat,” Averty claimed. The main drilling issue will likely be the shallow depths of the reservoirs, he added.

Geologists tackle Faroese volcanics

Jarðfeingi, the Faroese Geological Survey, has been re-examining large volumes of data from previous exploration activity offshore the islands ahead of the launch of the 4th Faroese licensing round next May. Only nine wells have been drilled to date, including Eni’s Anne Marie gas discovery. One of the main deterrents has been the complex volcanics that extend across the Faroese shelf, which have hindered imaging of potential underlying reservoirs. These were formed when the Faroe area was a conjugate part of east Greenland. Other petroleum provinces such as Angola and Brazil also have volcanics, but the layers are far less thick, making it difficult to draw meaningful analogies.

However, modern processing techniques applied to the extensive Faroese offshore 2D and 3D datasets are gradually improving the picture, said Jarðfeingi geologist Jana Olavsdóttir during ONS, and results will be announced in the run-up to next year’s round. “Now we see the base of the volcanics and the pre-rift, although there are no tie points,” she added. “But we can’t establish these until more wells are drilled through the volcanic sequence.”

Overhaul for Njord A platform

Statoil has awarded Kvaerner a $42.4-million contract to upgrade the Njord A semisubmersible platform, which had earlier been towed from the Norwegian Sea to Stord, western Norway, after being disconnected from the Njord field facilities. Kvaerner’s duties will include removing the derrick, flare and lifeboat system, and pre-fabricating new pontoons to increase the buoyancy of the hull.

Global Maritime completes the Njord A platform disconnection and tow to shore. (Photo courtesy Global Maritime).">Global Maritime completes the Njord A platform disconnection and tow to shore. (Photo courtesy Global Maritime)

The platform had been in operation since the start of production in the late 1990s. Statoil plans to modernize the facility to continue serving the Njord and Hyme fields beyond 2030, also tying in production from the 66-MMbbl Snilehorn and other undeveloped prospects in the area.

Snilehorn and Castberg are among 11 future Norwegian projects likely to go forward as a result of cost reductions, according to the Norwegian Petroleum Directorate. NPD said the various operators now anticipate combined investments of $18 billion, down by more than $14 billion from their previous estimates in 2014. Main factors have been modified development solutions, lower rig rates, and better planning to ensure that wells are drilled more quickly and therefore at lower cost. Choosing different subsea export routes has also brought down pipeline prices, NPD added.