Troll hull arrives amid North Sea start-ups

Dockwise's Mighty Servant 3 is shown carrying the Troll C platform hull through the Straits of Gibraltar on its journey from South Korea to Norway. The hull is 90.88 m long, 84.48 m wide, and 39.5 m high. It will support topsides with capacity to produce 125,000 b/d of oil and 320 MMcfd of gas. Photo courtesy of Dockwise.

Norsk Hydro AS has marked progress in the construction of a third platform for installation in Troll oil and gas field in the Norwegian North Sea.

The 14,000 metric ton lower hull structure recently arrived from its construction yard in South Korea to the Umoe Oil & Gas AS fabrication yard at Haugesund, Norway, where topsides construction is nearing completion.

Meanwhile, Norwegian state firm Statoil AS is preparing for sail-out of the Åsgard floating production ship (FPS) to the field in the Norwegian Sea.

Off the U.K., Enterprise Oil plc reported first oil from Pierce field, Kerr-McGee Oil plc began production at Janice oil field, and Conoco (U.K.) Ltd. disclosed first oil from Banff field. Meanwhile, Texaco North Sea U.K. Co. announced the approval of plans to expand Captain field.

Troll

The Troll C production semisubmersible hull was transported on the Mighty Servant 3 ship, operated by Dockwise NV, Meer, Belgium (see photo, p. 33). The ship left the yard in Ulsan on Nov. 30, 1998, and traveled via the Suez Canal and the Straits of Gibraltar to reach Norway 6 weeks later. The hull was skidded onto the ship, having been built on the quayside rather than in a dry dock. A Norsk Hydro official told OGJ the construction of the platform is going according to plan. It is 80% complete and is expected to be sailed out to the field in August. The official said mating of the topsides to the hull is scheduled for May, and first oil production is expected by yearend. The platform will produce oil from the thin oil layer in the northeastern part of Troll's gas province (OGJ, Sept. 2, 1996, p. 32).

Åsgard

Statoil's Åsgard oil FPS was set to sail for sea trials at the end of January, but its delivery to the field was delayed by vibration problems. The problem was traced to the ship's controllable pitch thrusters. The supports for the three electric motors that drive the thrusters were reinforced to curb vibration in the stern section, and tests were carried out to identify which running patterns should be avoided. The ship, Âsgard A, completed trials in Kloster Fjord before sailing out to the Haltenbanken area in early February. Âsgard oil production is expected to begin in early April, with output expected to reach 200,000 b/d (OGJ, Aug. 17, 1998, p. 66).

The 7.3 billion kroner ($975 million) FPS is part of the most complex subsea oil and gas producing system yet devised (OGJ, Aug. 17, 1998, p. 68). The ship also is part of the costliest overrun yet in Norwegian waters.

Instead of the 28.5 billion kroner investment estimated for the Halten- banken development, the outlay will now run to 37 billion kroner. As a result, some Norwegian sources describe the project as an "offshore Mongstad," referring to huge cost overruns in that refining project of the late 1980s.

Aker Stord, which finished the ship in an all-out effort in Norway, says it arrived from the Japanese builder without major systems, causing the delay. Another delay came Feb. 5, when storms prevented Statoil from sailing out the vessel to the field. At presstime, the FPS was expected to arrive in the Haltenbanken area sometime in February. The gas production platform, Âsgard B, and condensate storage tanker, Âsgard C, are still under construction.

Pierce

Enterprise began oil production from Pierce field on U.K. North Sea Block 23/22a and 23/27 last month, with initial production of 20,000 b/d of oil expected to reach a plateau of 45,000 b/d early this year.

Pierce was developed with the Berge Hugin production, storage, and offloading ship, leased under an initial 5-year contract from Norwegian owners led by Navion AS, Stavanger, Statoil's production ship/tanker leasing arm. Export of oil from the field will be by shuttle tanker.

At project sanction in August 1997, Enterprise estimated Pierce's reserves at 84 million bbl of oil and 202 bcf of gas. A well drilled in nearby North Pierce prospect added another 20 million bbl of oil to the reserves estimate.

Janice

Kerr-McGee announced first oil from Janice field on Block 30-17a in the central North Sea. The announcement comes just 17 months after U.K. Department of Trade and Industry approval of the project.

Janice, 175 miles east-southeast of Aberdeen in 240 ft of water, is being developed by recompleting two appraisal wells and drilling five more production wells and four water-injection wells.

Reserves are estimated at more than 70 million bbl of 37? gravity oil. Kerr-McGee expects production to peak at 55,000 b/d in first half 1999.

"Extra processing capacity is available to allow the Janice floating production unit to serve as a hub for future developments," said Kerr-McGee.

Janice oil will be transported via a new 16-km, 14-in. pipeline to the southern Y of the J-Block spur, then through Norpipe from Ekofisk field to Teesside, U.K. Associated gas will be shipped through a new 36-km, 12-in. pipeline to nearby Judy platform. The line has a capacity of more than 100 MMcfd, which is more than needed to transport Janice gas, thus encouraging further developments in the area.

Interests in Janice are: operator Kerr-McGee 50.9%, Phillips Petroleum Co. U.K. Ltd. 24.4%, Agip (U.K.) Ltd. 18.2%, and Svenska Petroleum Exploration U.K. Ltd. 6.5%.

Banff

Conoco reported first oil from Banff field, on Blocks 29/2a and 22/27a in the U.K. North Sea, about 125 km east of Aberdeen.

The field has an initial production rate of 6,000-34,000 b/d of oil. Peak production from the field is expected to be 60,000 b/d of oil and 40 MMcfd of gas. Partners in the field include operator Conoco 31.7%, Enterprise Oil Exploration Ltd. 27.9%, Ranger Oil (U.K.) Ltd. 26.2%, British-Broneo Oil & Gas plc 12.4%, and Petrobras North Sea Ltd. 1.8%.

Captain

Texaco plans to raise U.K. Block 13/22a Captain field output to 85,000 b/d from 60,000 b/d by developing a reservoir in the eastern sector of the field. Captain was brought on stream in March 1997 with a wellhead platform linked to a production, storage, and offloading ship.

Beginning in summer 2000, Texaco is to start development drilling ahead of installation of subsea production facilities tied back to a new process and utilities platform, which will be bridge-linked to the existing wellhead platform.