During the last five years Statoil and its partners have invested as much as NOK 46 billion on the Troll field, which came on stream in 1995. The investment level will remain high for many years to come.
Troll is the story of achieving the impossible. The oil proven in connection with the largest gas discovery ever made in the North Sea was considered non-recoverable. Field production so far totals 1.5 billion barrels of oil.
“The work we have done on Troll illustrates how Statoil operates to manage the offshore resources properly and safely to ensure value creation for the owners and the Norwegian society at large,” says Kjetil Hove, senior vice president for operations North Sea east in Development and Production Norway.
At this year’s Offshore Technology Conference in Houston he used Troll as an example of how Statoil’s activities on the Norwegian continental shelf, including technology development and expertise build-up, has turned Statoil into the world’s largest offshore operator.
“An innovative approach to challenges has helped develop new technology, high expertise, concepts and solutions that extend the field life and enhance value creation, which in turn have led to spinoffs far beyond our area of activity,” says Hove.
In addition to producing oil from the Troll B and C platforms, the field is today the cornerstone of Norwegian gas production, and one of the most central fields delivering gas to the European market.
The field contains around 40% of total gas reserves on the NCS.
Largest oil producer on the NCS
Corresponding to half the size of Mexico City, Troll is today among the largest NCS oil fields.
When the discovery was made, however, it was considered impossible to commercialise the oil due to tilted layers and a very thin oil zone in the reservoir.
To be able to recover oil from the thin layers Statoil has, in collaboration with the suppliers, developed advanced technology that enables drilling of horizontal multilateral wells.
The Troll wells are drilled down to a reservoir located around 1,320 metres below the seabed, where they are split into two to four branches.
Each branch extends around 3,000-4,000 metres horizontally into the reservoir. A total of more than one million metres have been drilled in the reservoir from 180 production wells.
Technology to optimise production from the horizontal branches has also been developed to achieve higher total production per well.
“In May we will reach the milestone of 1.5 billion barrels of oil produced since the startup in 1995. We are very pleased as we are able to realise both oil and gas values of this vital field,” says Hove. He praises the active partners who challenge and provide knowledge and expertise.
“Our ambition is to produce 2,1 billion barrels. In 2013 the field produced 124,000 barrels of oil per day. Even after almost 19 years of operation there are currently four drilling rigs in operation on the field, and this activity will continue until 2020,” says Hove.
Up to 250 horizontal production wells will be drilled in this period. The field is operated by Statoil, with Petoro, Shell, Total and ConocoPhillips as licence partners.