Lloyds List: Challenges are overcome as Kristin comes on stream: “In the Norwegian Sea, Norsk Hydro and Shell have started drilling the first of eight development wells on the large Ormen Lange gas field using Smedvig's drillship West Navigator.”: Tuesday November 08, 2005
Statoil had to deal with high-temperature, high-pressure reservoir and environmental challenges, writes Martyn Wingrove
STATOIL has started pumping gas and light oil from the Kristin production semi-submersible in the Norwegian Sea.
Technology advances and Nkr21.6bn ($3.3bn) of investments were required to bring this demanding project on stream and beat the various environmental and reservoir challenges.
The partially privatised oil company has developed the field using 12 subsea wells clubbed together in four subsea templates, tied into the floating production platform.
The field lies in blocks 6406'2 and 6506'11 in licences awarded in 1993 and 2000 and was discovered in 1997.
Gas from the platform will be piped to the Karsto processing plant north of Stavanger by the Asgard Transport pipeline and light oil in the form of gas condensates exported via the Asgard C storage and offloading ship on to shuttle tankers.
Statoil plans to recover at least 43bn cu m of gas and 240m barrels of condensate and will eventually look to increase these reserves through further wells and technology advances.
Challenges with this project involved the high pressures and high temperatures of the reservoir and complex well structures required.
Located 4,500 m below the seabed, the Kristin reservoir has a record pressure of 911 bar and temperatures as high as 170 degrees centigrade.
'These represent the most demanding conditions ever faced by a development on the Norwegian continental shelf,' said operations vice-president Eileen Buen.
Of the 12 wells completed with subsea trees eight are highly deviated into this deep reservoir, representing an industry first for a HPHT field.
The project has been hindered by the reservoir challenges as well as lifeboat problems but has still come on line only one month late.
Output is through two wells and will build up more slowly than previously anticipated to a peak level of around 18m cu m of gas and 126,000 barrels of condensate a day by the third quarter of next year.
Statoil's partners in the project include state entity Petoro, Oslo-listed Norsk Hydro and oil majors ExxonMobil, Eni and Total.
The Kristin platform represents a new piece of infrastructure in the Norwegian Sea which Statoil hopes to utilise to develop other fields in the area.
It has already lined up the first satellite in the Tyrihans field, which Statoil hopes will be brought on stream in 2009 once there is spare capacity at Kristin.
According to the ministry of petroleum this field holds reserves of around 25m cu m of oil, 33bn cu m of gas and 5.8m tonnes of natural gas liquids.
There are a number of other discoveries in the area surrounding Kristin including Lavrans, Erland and Ragnfrid, so Statoil has an inventory of other satellites to use.
Meanwhile, Statoil has started drilling on the Gudrun discovery in the Sleipner area of the North Sea using the Transocean Leader semi-submersible rig.
The appraisal well in block 15'3 is also high temperature and high pressure, targeting a deep reservoir discovered in 1975 and last drilled in 2001.
'If Gudrun contains large volumes of oil one development alternative could be to tie the find back to the Sleipner fields,' said Lars Jan Jaarvik, Statoil's exploration manager for the Troll-Sleipner area.
But it lies 50 km north of the fields, so a stand alone development could be another option.
Statoil's partners in the well are Marathon, BP and Gaz de France.
Also in Norway, Italian oil major Eni has started an appraisal well on the Goliat oil field in the Barents Sea using Ocean Rig's semi-submersible Eirik Raude in block 7122'7.
In 2000, Eni discovered oil at Goliat and the next year it drilled the first appraisal well.
Both were tested at rates of more than 4,000 barrels a day and Eni hopes that another appraisal well will find more reserves to the south.
In the Norwegian Sea, Norsk Hydro and Shell have started drilling the first of eight development wells on the large Ormen Lange gas field using Smedvig's drillship West Navigator.
The vessel, which is working on a Nkr1.17bn contract to Smedvig, will drill the wells through two subsea templates installed back in September in 850 m of water.
Hydro expects that the ship will take two years to drill and complete all of the eight wells.
It is the operator of the field during the development phase and manages all construction operations, while Shell is responsible for the planning and execution of the drilling programme and for reservoir management.
Gas production is expected to begin on Norway's largest gas field in October, 2007.
- Stavanger independent Revus Energy has acquired 30% of North Sea block 1'3 from Dong Norge to appraise and develop small oil fields.
The block, which lies west of the Ula and Gyda platforms, includes the Oselvar oil discovery and other exploration prospects.
Revus and Dong plan to drill an appraisal well on Oselvar next year in order to firm up reserves ahead of a development using existing infrastructure in the area.
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