Norsk Hydro AS has let a 1.6 billion kroner ($240 million) contract to Aker AS, Oslo, for construction of gas processing platform topsides for installation in Oseberg field on Norwegian Blocks 30/6 and 30/9.
Texaco North Sea Co. Ltd. plans to deploy a production semisubmersible unit, formerly used to deplete U.K. North Sea Emerald field, in its development of Galley field on U.K. Block 15/23a.
Meanwhile, Saga Petroleum AS, Oslo, is to study feasibility of building a joint pipeline to export light oil from two discoveries in the Norwegian Sea off central Norway.
Oseberg gas
Hydro's new gas processing platform will be used to help deplete Oseberg gas reserves, estimated at 115 billion cu m, beginning in October 1999.
Total development cost for Oseberg gas is expected to be more than 4 billion kroner ($600 million), including pipelines and modifications to existing facilities.
Three oil production platforms are in Oseberg field. The new gas platform will be designated Oseberg D and bridge-linked to Oseberg A, which in turn is bridge-linked to Oseberg B.
Gas production will involve use of wells drilled during oil depletion, controlled and maintained from Oseberg B platform with existing drilling facilities.
As Oseberg field comes off its oil production plateau around 2000, more associated gas will be produced. This gas has been reinjected so far, but Hydro reckons it can now recover 75% of reinjected gas.
Oseberg D platform will be installed 100 m from Oseberg A in 109 m of water. It will have capacity to process 32 million cu m/day of gas and reinject some gas.
Oseberg D topsides will weigh 7,500 metric tons and be completed in spring 1999 for installation that May. Topsides will be built at Aker's Verdal yard. The jacket construction contract will be awarded this autumn.
Oseberg field interest holders are: operator Hydro 13.68%, Statoil 64.78%, Saga 8.55%, Elf Petroleum Norge AS 5.78%, Mobil Development Norway AS 4.33%, and Total Norge AS 2.88%.
Galley
For Texaco's Galley development, the Emerald Producer semi will be upgraded and have its name changed to Northern Producer. Field development cost is estimated at £140 million ($224 million).
Texaco will lease the vessel from shipping firm Seatankers, which in turn is to award a 10-year management contract to Atlantic Power & Gas Ltd., Aberdeen, to operate the unit during production.
Two development wells will be drilled ahead of first production from Galley, anticipated in first quarter 1998. These are expected to yield a combined 35,000 b/d of oil and 50 MMcfd of gas at peak. A third production well is planned when the field is on stream.
From the subsea wellheads, oil and gas will arrive at the Northern Producer for processing. Oil and gas will be exported in separate pipelines to Texaco's Tartan on nearby Block 15/16a.
Galley's oil will join the output from Tartan in a pipeline to Flotta terminal in the Orkney Islands, while gas will be added to Tartan's flow to St. Fergus terminal, north of Aberdeen.
Galley reserves are estimated at 28 million bbl of oil and 40 bcf of gas. Field license partners are operator Texaco 67.4%, Enterprise Oil Production Ltd. 17.4%, and Lasmo (TNS) Ltd. 15.2%.
Early Galley production will be from the field's northern and southern accumulations. Texaco is planning to deplete eastern and western accumulations in a second phase of development.
Pipeline study
Saga discoveries have recently been named Kristin and Lavrans.
The pipeline under consideration would take liquids from these, from Aasgard field under development, and Tyrihans, which is being considered for development.
The pipeline would be the first oil export pipeline from this recently opened area and could help make other discoveries in the Haltenbanken offshore region viable for development.
