Apache, which has headquarters in Houston, said it started production at the Tonto oil field offshore.
"Tonto-1, the first producing well, came on stream at an initial rate of 10,346 barrels of oil per day," the company said.
Apache said the field is its third in the region to come online in the last three years. Apache said all three were developed under the terms of a measure from the British government that gives operatives economic incentives for their work.
BP in March announced that it joined Chevron, ConocoPhillips and Shell in a decision to move forward with plans for a third phase of operations at the Clair oil field in the North Sea.
The British government said reserves in the region may be as much as 17 percent of the country's total oil and natural gas potential.