Saudi Arabia's Khurais oilfield is pumping at around a million barrels per day, state oil company Aramco said on Monday.

Khurais project is the biggest in Saudi history and the largest ever single addition to global oil supplies.

'The facilities are designed for 1.2 million (bpd) now but we can produce up to 1.4 million because this field is considered to be virgin field,' Yousef al-Furaidan, manager of the production department, told reporters at the field.

'What we produce on a daily basis is different from one day to another because we are responding to the demand and responding to inventory in the downstream but today we are producing about 1 million (bpd), 1.050, yesterday we were producing 700,000 so it depends,' he said.

'We produced 1.2 mln bpd from the first day then we responded to demand might be reduced by 300,000-400,000 (bpd) depending on the demand,' he added.

Khurais took the main share when the kingdom added more than 2 million bpd to its output capacity in 2009. Saudi Arabia is the only country in the world that has significant spare oil output capacity that can be brought into production swiftly if needed.

Khurais' plateau of production is a minimum of 30 years of sustainable output at the current rate.'We intend to maximize the recovery of the field as always the case of any Saudi Aramco field development,' Furaidan said.

'Employing horizontal technologies in drilling wells reduced well numbers by 63 percent from 618 to 230 to produce the same amount of crude.'

The field holds 27 billion barrels of oil and was the largest of 3 oilfield projects that boosted Saudi Arabia's output capacity to 12.5 million bpd. Opec's leading member pumped 8.33 million bpd in January, according to a Reuters survey.

Khurais contains prized Arab Light crude easily suited to refining high value transport fuels. Aramco's giant Ghawar was producing at 6 million bpd, Furaidan said.-Reuters