Much of the major installation work for development of Norway's Troll field will take place this year.
Here is a guide to what will go where in the Norwegian North Sea giant.
The need for a guide arises because Troll is a complex field, being developed as two projects under different operators. Originally there were Troll gas and Troll oil projects, which then became East Troll and West Troll. All seemed relatively simple.
Then the projects became officially known as Troll Phase 1 and Troll Phase 2, and there is now talk of a Troll Phase 3. The platforms to be installed were designated Troll A and Troll B.
Confusion set in because different sources of information used different names for the fields and their platforms. But the reason for development has always been easy to grasp: Total Troll field reserves are estimated at 380 million bbl of oil and 46 tcf of gas.
EAST TROLL
East Troll lies on Blocks 31/3 and 31/6 and holds about two thirds of the field's gas. Troll's gas reserves in the large eastern reservoir will be developed as Troll Phase 1, with a fixed platform called Troll A.
Development operator is Norske Shell AS. Den norske stats oljeselskap AS will take over at start of production.
Troll A:s combined topsides and gravity base structure will be the world's tallest production platform at 430 m. Topsides and base have been towed to a deep fjord at Vats, where Norwegian Contractors AS will mate them.
Mating was slated for Jan. 15-20, but bad weather delayed the operation to Jan. 22 at the earliest.
Platform A is expected to be towed to the field in May. Gas production is scheduled to begin Apr. 1, 1996. Gas will be piped ashore to a new processing plant at Kollsnes prior to export to European markets.
WEST TROLL
Troll's oil reserves will be developed as Phase 2. The oil platform, designated B, will be sited in West Troll on Block 31/2. A thin oil layer covers most of Troll field, but only in West Troll is it worth developing.
West Troll has two distinct parts: an oil province, which contains the thickest oil pay; and a gas province, which has a thin oil layer to be depleted under Phase 2, as well as gas destined for development as Phase 3.
West Troll's platform B will be the world first concrete semisubmersible production platform. Its deck is being built in Stavanger for shipment in February to Hanoytangen near Bergen, where the concrete floater is being completed.
Phase 2 operator Norsk Hydro AS says B platform modules will be lifted onto the floater in April, at which time installation of subsea oil production manifolds, four in the oil province and one in the gas province, will begin.
Tow of the platform to the field is set for early July. Phase 2 production is likely to start ahead of Phase 1, with the target for first oil as Nov. 15, 1995. Oil will be piped to Mongstad terminal.
Operatorship of West Troll gas development, also know as Phase 3 development, has not been settled. Neither has the development method.
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