BP has announced it is introducing new technology which will significantly boost the amount of oil it can extract.
It will be used for the first time offshore in the £4.5bn Clair Ridge development west of Shetland.
If left to its own devices an oil well will deliver only about 10% of the crude it contains. By then its pressure is exhausted.
However, the new technique means the energy firm will bring in an extra 42 million barrels from Clair Ridge alone.
The established industry technique of waterflooding brings more oil to the surface. Sea water is pumped into the oil-bearing rocks deep below the seabed.
But even then almost two thirds of the crude will remain beneath the waves.
BP's new technique - called LoSal EOR and announced here at the British Science Festival in Aberdeen - promises to increase both the life and yield of oilfields worldwide.
Instead of sea water, it will inject water from which most of the salt has been removed. It'll still be too salty to drink, but enough to force the crude to separate itself from the rock and come to the wellhead.
BP will be spending $120m on desalination equipment for Clair Ridge. It will produce up to 25,000 tonnes of water every day and the reward will be an extra 42m barrels of oil from that oilfield alone.
The science underpinning the technique is that water which is low in salt helps loosen the bonds between crude oil and the rock which surrounds it. Too salty, and the oil binds to the rock more tightly.
BP say there are likely to be benefits for oilfields worldwide.
The field trials to prove the science worked were held in Alaska and the field expected to use the technique after Clair Ridge is in the Gulf of Mexico.
Aberdeen University economist, Professor Alex Kemp, described it as a "landmark announcement of great significance".
He said the technique was being studied by several major oil companies and there was scope for it to be replicated elsewhere.
He says the method could extend the lives of oilfields, sustaining more jobs for longer. It could boost industry profits and increase tax revenues.