Sixty per cent of the oil in Statoilâs Statfjord field in the North Sea has now been recovered. This milestone was passed on 13 April.
Just under 3.8 billion barrels have been produced since the first platform came on stream in 1979, reports Atle Aadland, head of the Statfjord reservoir development department.
After reaching an output of more than 700,000 barrels of oil per day in the mid-1980s, the field is now down to about 188,000 barrels.
The water cut has steadily increased, however, and now accounts for 80 per cent of the liquids produced.
Gas and about 300,000 barrels of oil from other fields are also processed every day on the Statfjord installations.
Statfjordâs high recovery factor reflects the good job done by the operations organisation with a fantastic reservoir, reports Mr Aadland.
The quality of the Jurassic sandstones is good, with fine pressure communication across large parts of the reservoir and easy flow conditions for oil and gas.
But challenges lie ahead. Plans call for 15 additional wells and more than 100 downhole interventions during the year.
âGood reservoir understanding and a high level of activity are necessary to recover oil from ever-smaller pockets,â Mr Aadland explains.
In addition, the three platforms must be maintained and upgraded.
The goal is to recover up to 68 per cent of the stock tank oil originally in place (Stooip) in Statfjord. Opportunities for maintaining production beyond 2012 will also be assessed.