The United Arab Emirates is to shut down the Lower Zakum West field, which produces 280,000 barrels a day of crude oil, in late October for between 17 and 25 days, officials said Monday.

"There will be a total shutdown of Upper Zakum West from Oct. 26 for tie-ins of a new gas (reinjection) facility," a planning official at Abu Dhabi Marine Operating Co., or ADMA-OPCO, responsible for developing Abu Dhabi's offshore oil and gas reserves, told Dow Jones Newswires by telephone. "It is a debottlenecking project to increase production of oil," he said.

The facility will be used to inject gas into oil wells, exerting pressure in the reservoir to enable more oil to be pumped out.

Abu Dhabi , the capital of the U.A.E., holds some 90% of the country's oil and gas reserves, and plans to raise oil output to 4 million barrels a day from around 2.6 million barrels a day now.

Lower Zakum Field is one of the largest oil fields in the world, producing some 340,000 barrels of oil a day. During the shutdown, output of 60,000 barrels a day will continue from Upper Zakum Central, the ADMA-OPCO official said.

An official from Technip SA (TKP), one of the contractors building the facility along with the U.A.E.'s National Petroleum Construction Co., said that oil output would be stopped for up to 25 days.

"Production will be stopped for between 17 and 25 days for some tie-ins to be done to bring on a gas processing facility for the compression of gas for reinjection into the well," the official said.

The U.A.E. is the third largest oil exporter in the Organization of Petroleum Exporting Countries, producing 2.58 million barrels a day of crude last month, according to a Dow Jones Newswires survey.

Lower Zakum West will also be shut down for three days from Wednesday or Thursday, the official at ADMA-OPCO.