MORE OIL AND GAS FLOWING IN NORWEGIAN NORTH SEA

Gas from East Sleipner field in the Norwegian North Sea began flowing to European customers Oct. 1 as scheduled.

lt's the first stage of a contract that operator Den norske stats oljeselskap AS said is among the world's biggest ever commercial deals.

Meantime, Brage field partners have started oil production from two of six predrilled wells at a platform in 450 ft of water on Block 31/4 in the Norwegian North Sea.

Brage operator Norsk Hydro AS said Brage production has stabilized at about 30,000 b/d plus an unreported volume of associated gas since start up.

EAST SLEIPNER

East Sleipner is the first field on stream under the Troll gas sales contract, signed in 1986. Companies in Germany, Netherlands, Belgium, France, Spain, and Austria have bought Troll gas.

Under the Troll contract, Norwegian gas producers will deliver about 35 tcf to Europe during almost 30 years. The contract, which covers one third of Norway's known gas reserves, is worth about 700 billion kroner ($100 billion) at current gas prices.

Troll is the only other field so far earmarked to deliver gas under this contract. It will go on stream in October 1996.

Gas sales under the Troll agreement are expected to plateau at about 1.6 tcf/year in 2005, with German companies Ruhrgas AG of Essen, BEB Erdgas and Erdol GmbH of Hanover, and Thyssengas GmbH of Duisburg taking a combined 780 bcf/year.

Other customers are Gasunie and electrical power generator SEP of Netherlands, Distrigaz SA and power generator Electrabel of Belgium, Austria Ferngas GmbH and OMV Aktiengesellschaft of Austria, Gaz de France, and Enagas of Spain.

Dutch companies will take a total 200 bcf/year at plateau production, while Belgium will receive 195 bcf/year, France 280 bcf/year, Austria 60 bcf/year, and Spain 75 bcf/year.

Ruhrgas recently chose to take an extra 55 bcf/year of gas when the Troll gas project goes on stream in 1996 (OGJ, July 26, p. 45).

EAST SLEIPNER

Development of East Sleipner field in Block 15/9 hit a crisis in summer 1991, when the concrete gravity base structure that was scheduled to carry the platform topsides sank in a fjord outside Stavanger during ballasting trials.

Statoil built a new base very much like the first. Meeting the Oct. 1 deadline on such a big contract was seen by Statoil as crucial to its credibility as a gas supplier (OGJ, Aug. 30, p. 34).

On Sept. 29 the last of four wells due to deliver Sleipner's first gas was given a final test to determine production rate. On deadline day, the target rate of 370 MMcfd was achieved without the need to call on gas from other Norwegian fields.

During the runup to Oct. 1, Statoil had a workforce of 610 on East Sleipner platform. Manning on Sleipner A platform is to fall to 60 people in 1996, when West Sleipner field is placed on stream.

Meantime, more wells are to be drilled in East Sleipner field, and equipment to handle gas from West Sleipner will be installed on Sleipner A platform.

West Sleipner is to be developed using two conventional unmanned steel platforms: a gas processing platform bridge-linked to Sleipner A and a wellhead platform 7 miles away (OGJ, May 10, p. 34).

PIPELINES

Start of East Sleipner production gave the Zeepipe gas trunk tine its first commercial use in moving most of the gas from East Sleipner about 830 km to Zeebrugge, Belgium, where it entered Europe's gas grid.

Some of the gas traveled through the existing Statpipe line to Emden, Germany. Austrian deliveries are handled by Ruhrgas, with handover at Oberkappel on the Austrian border.

Gas destined for Spain travels from Zeebrugge to Blaregnies near the French/Belgian border through a dedicated pipeline built by Distrigaz. It then enters the Gaz de France network en route to Port de Larrau for transfer to Enagas.

A third Norwegian trunk line, the 40 in. diameter Europipe, is due on stream in 1995 to link a new riser platform on Block 16/11 with Emden terminal.

East Sleipner deliveries will continue at 370 MMcfd until Oct. 1, 1994, when the contract requires supplies of 720 MMcfd. This rate is required until Oct. 1, 1996, when Troll gas field is due on stream.

BRAGE FIELD

Brage oil flows about 75 miles from the better of the field's two reservoirs through Oseberg field's offshore pipeline system to Sture oil terminal on the Norwegian coast north of Bergen.

Production is to increase gradually as each of the remaining four predrilled wells goes on stream, reaching Brage facility's design capacity of 85,000 b/d before yearend.

Brage development was accomplished in 40 months and went on stream about 3 months ahead of schedule. Installation, hookup, and commissioning of offshore facilities was completed in 3 months.

Brage gas production facilities are designed to handle about 60 MMcfd. Brage gas flows through Statpipe offshore pipeline to shore at Karste, Norway, where liquid fractions are separated.

Gaseous hydrocarbons, mostly methane, are reinjected into Statpipe for transport through a compression platform on Norwegian North Sea Block 16/11S and through the Ekofisk complex on Norwegian North Sea Block 2/4 for final delivery through Norpipe to Emden, Germany. Separated Brage gas liquids are to be shipped to market by tankers.

Norsk Hydro installed Brage production platform and laid related oil and gas pipelines at a cost of about $1 billion. Cost of the six predrilled wells and as many as 26 more development wells is expected to amount to about $400 million.

Brage field recoverable reserves are estimated at 250 million bbl of oil and 100 bcf of gas. Total oil production of about 242 million bbl is expected during Brage's planned 13 year life.

Brage field extends into two neighboring Blocks 31/7 and 30/6.

Partners on Blocks 31/4 and 31/7 are operator Norsk Hydro 23.2%, Den norske stats oljeselskap AS 46%, Exxon Corp. unit Esso Norge AS 17.6%, and Neste Corp. unit Neste Petroleum AS 13.2%.

Interest owners on Block 30/6 are Norsk Hydro 22.4%, Statoil 47%, Esso 16.3%, Neste Petroleum 12.3%, Ste. Nationale Elf Aquitaine 0.7%, Saga Petroleum AS 0.5%, Mobil Exploration Norway Inc. 0.5%, and Total Cie. Francaise des Petroles 0.3%.

Copyright 1993 Oil & Gas Journal. All Rights Reserved.