NEW YORK (CNNMoney.com) -- Oil production at BP's Prudhoe Bay oilfield in Alaska, already running at half capacity due to pipeline corrosion, is being cut by another 90,000 barrels per day for several days due to a technical fault.

A company spokesman said Wednesday output at the biggest oilfield in the United States had been reduced to 110,000 barrels per day after a natural gas compressor in Gathering Center 2 failed.

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"We anticipate that fixing the compressor will require several days," said BP (Charts) spokesman Daren Beaudo told wire services.

The spokesman said no one was hurt and no oil was spilled in the latest incident, which has added to worries over an oil market strained by reduced Nigerian supply and fearful of potential disruptions in the Middle East.

Oil prices initially jumped on the news in premarket trade, but later settled back as the initial shock wore off.

BP had originally planned for 400,000 barrels of oil a day to be off line for several months, and as a result had place orders to supply its West Coast refineries, where most of Prudhoe's crude is shipped, with supplies from Asia and other places.

Traders were closely watching inventory reports for signs of a supply problem, but have so far seen few signs of a major disruption.

"(They) are remaining quite healthy despite the problems in Prudhoe Bay," said Bob Yawger, an oil broker at Man Financial in New York. "And it doesn't seem like (the recent shutdown) will be too long lasting."

Prudhoe Bay had previously been pumping about 200,000 bpd, around half its normal output, after serious corrosion in a pipeline led BP to shut down the eastern half of the field earlier this month.

After discovering the corrosion in early August, BP said it would have to close the entire field, which accounts for about 8 percent of total U.S. output. U.S. regulators later cleared it to keep operating the western section.

But the corrosion problems and shut down have raised question over BP's maintenance program, when it knew of problems with the pipeline, and why it waited so long to fix them.

Federal officials are investigating two year old documents from an engineering firm that warned BP of severe corrosion in its pipes two years ago, the Wall Street Journal reported Thursday.

The state of Alaska is also probing the incident, trying to determine if it will sue BP for lost revenue from the closure, which is estimated to be costing the state roughly $6 million a day.

And there have also been reports that BP's partners in the field, ConocoPhillips (Charts) and Exxon Mobil (Charts), are not happy with the shut down and are exploring possible litigation as well.

BP is scrambling to find alternative routes for the oil that would normally have been produced by the eastern half of Prudhoe Bay, where it is replacing major transit lines,. Officials have cautioned against expectations that output would be quickly brought back to normal.

Engineers are working on three different bypass lines that could eventually fully restore production.

-from staff and wire reports

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