Britain could reap a $240 billion North Sea oil bonanza using carbon dioxide to extract oil, but only if the current infrastructure is enhanced, a study says.

Research at Durham University shows that using CO2 to enhance recovery could yield an extra 3 billion barrels of oil during the next 20 years, a university release said. That amount of oil could power, heat and fuel transport in Britain for two years with every other form of energy switched off, researchers say.

The process is almost carbon neutral, with almost as much carbon being put back in the ground as would be taken out, they say.

"Time is running out to make best use of our precious remaining oil reserves because we're losing vital infrastructure as the oil fields decline and are abandoned," Jon Gluyas, a professor in Durham's department of earth sciences, say. "Once the infrastructure is removed, we will never go back and the opportunity will be wasted.

"We need to act now to develop the capture and transportation infrastructure to take the CO2 to where it is needed," Gluyas said.

Oil is usually recovered by flushing oil wells through with water pressure. Since the 1970s oil fields in Texas have been successfully exploited by pumping CO2 as a liquid into parts of the reservoirs water injection doesn't reach, resulting in a 4 percent to 12 percent increase in oil production.