Norway's Statoil is trying to extend the life of its giant Statfjord field in the North Sea by depressurising the reservoir to recover an extra 300-400 million barrels of oil equivalent, the equity partners say.
Equity partner ExxonMobil says the proposed Statfjord Late Life project would start up towards the end of 2006, and would augment daily production by 70,000 barrels of liquids and 370 million cubic feet of gas.
Current production averages 240,000 barrels per day (bpd) of oil, and 210 million cubic feet of gas, according to operator Statoil, which says it expects an investment decision on the Late Life project later in 2004 or in early 2005.
Statoil says the field has already exceeded most expectations since its discovery in 1974: recovery ratios have been upgraded several times, and the Norwegian firm now hopes to extract close to 70 percent of the oil originally in place.
The Late Life project would lower the pressure of the reservoir, liberating dissolved gas from the remaining oil in place, a method used successfully in developing the maturing North Sea Brent field.
Statoil said on Thursday this strategy would yield an extra 15 million cubic metres of oil (about 100 million barrels) and 30-40 billion cubic metres of gas (equivalent to about 200-260 million barrels of oil), and extend the production period on Statfjord by 8 to 10 years until around 2018.
"Submission of a plan of development and operation for the Statfjord Late Life Project to the government is expected late December this year," said a Statoil spokeswoman.
If Statfjord Late Life goes ahead, gas from the project will flow to the UK through the Flags pipeline from October 2007.
Both Britain Norway are keen to extend the oil production lifespan of the North Sea. Britain says as little as half of its North Sea reserves have been extracted to date, while Norway estimates it is only 40 percent of the way through its reserves.
However, the scarcity of big new finds, and the availability of more efficient opportunities in new exploration hotspots such as West Africa and the Caspian Sea region, have drawn away the attention of global majors.
North Sea output has been falling for the last five years, and the pace of decline is set to accelerate without significant new investment, a recent study by venture capital group 3i said.
That study placed the onus for future developments on smaller independent exploration and production companies, taking over the impetus for new investments from the majors.
Other Statfjord partners include Shell, ChevronTexaco and divisions of ConocoPhillips.