Saudi Arabia's first carbon capture and storage pilot project, located at its Ghawar oilfield, may boost oil recovery rates by 20 percentage points, oil minister Ali al-Naimi said.

Carbon storage schemes are being promoted around the world as a way to slow global warming by preventing the release of carbon dioxide into the atmosphere. But big oil producers such as Saudi Arabia are also keen to develop the schemes as a way to extend the life of oilfields.

By injecting carbon dioxide into depleted oil fields rather than more precious resources such as water, they can increase pressure in the fields and maximise yields, although the technology is still expensive.

Ghawar, which has been pumping since 1951, produces over 5 million barrels per day, almost half Saudi Arabia's oil output.

The carbon project, developed by national oil firm Saudi Aramco, started operating this year - 40 million cubic feet per day of carbon dioxide will be captured at the Hawiyah gas recovery plant and then piped 85 km (53 miles) to the Uthmaniyah area.

At Uthmaniyah, it will be injected into flooded oil reservoirs under high pressure to enhance oil recovery, storing an estimated 800,000 tonnes of carbon dioxide every year. Aramco has previously used water injection at the field.

"This pilot will show us whether we can take the Ghawar field from 50 per cent (oil) recovery to 70 per cent recovery plus or minus," Al-Naimi told a news conference in Riyadh on Wednesday.

The field has estimated remaining proven oil reserves of 75 billion barrels, according to the US Department of Energy. Currently, Saudi oilfields have recovery rates of about 50 per cent of their contents, but some fields have reached almost 70 per cent through water injection, Naimi added.

"It is hoped that this pilot project can demonstrate that it is possible to increase oil recovery at commercially sustainable costs," said Sadad al-Husseini, a former top executive at Saudi Aramco.

There are currently 15 carbon capture and storage projects in operation worldwide, according to a report by Global CCS Institute released on Thursday. - Reuters