DUBAI: Saudi Arabia and US oil major Chevron Corp have successfully extracted previously unreachable Saudi crude by injecting steam into oil fields to loosen sludge-like deposits, Chevron said.Steam injection tests began on six wells this year in the Wafra oil field, located in a neutral zone shared by Kuwait and Saudi Arabia, Chevron spokesman Michael Barrett said on Wednesday.
Saudi Oil Minister Ali Naimi said steam injection could be used to add "tens of billions" of barrels to the kingdom's proven reserves of 260billion barrels - the world's largest, the Wall Street Journal reported this week.
The dense sludge-like oil had previously been considered unrecoverable, since it is so thick it cannot be pumped to the surface like lighter crudes. But injecting steam into the reservoir heats the viscous, heavy oil to a syrupy consistency that allows it to be pumped out, Barrett said.
Rising prices have pushed oil companies and governments to try to capitalise on languishing deposits of oil that were previously thought too difficult to exploit. In Canada, too, steam is being used to coax oil from the enormous tar sand deposits in northern Alberta.
Chevron, based in San Ramon, California, will incorporate its test results into a large-scale effort to extract oil from the Wafra field, Barrett said.
Currently, Chevron operates just one steam injection well, four production wells and one observation well in Wafra.
That will grow to 16 steam-injection wells and 25 producing wells, Barrett said. The US oil company declined to say when commercial production would begin.
Chevron and Saudi oil officials want to see if the technique will work in the trickier Middle Eastern oil geology dominated by porous rock formations.
Besides Wafra, the Saudis are considering using steam injection at the gigantic Manifa field, also thought to cradle a large reservoir of heavy oil, the Journal reported.
Barrett said Chevron uses steam to heat and recover 650,000 barrels of heavy oil per day, mainly from fields in Bakersfield, California; Indonesia and Venezuela.
