UK oil giant BP has increased crude production at its Prudhoe Bay field in Alaska - the biggest in the US - after overcoming a technical problem.
BP is now replacing 16 miles of Alaskan pipeline
Last week BP cut oil output by 90,000 barrels per day (bpd), lowering production to 110,000 bpd, or about a quarter of its normal level of pumping.
It has now fixed the problem, caused by the failure of a gas compressor and would take several days to fix.
Earlier this month BP closed half the field because of pipeline corrosion.
It is to replace 16 miles of corroded pipeline at a cost of about $170m (£89m).
BP has been accused of misleading regulators over the condition of its pipelines, although it has denied all the allegations.
It had previously considered a full closure of the field.
The problems are now being investigated by both Alaska's Attorney General, David Marquez, and the US Environmental Protection Agency.
The company's partners in the Prudhoe Bay field are ConocoPhillips and Exxon Mobil.