Top Chinese oil and gas firm PetroChina Co. Ltd. (NYSE: PTR) is adding new production wells at one of its main oil fields, in northeast China, aiming to build 1.06 million tonnes of new annual capacity this year, parent company CNPC said on June 1.

PetroChina plans to drill a total of 690 new wells this year at the Liaohe field in Liaoning province, part of the state oil major’s campaign to sustain production at mature fields, which also include top field Daqing in Heilongjiang province further north.

PetroChina wants to maintain Liaohe’s output at 10 million tonnes per year (or 200,000 barrels per day) after decades of development, CNPC said.

The major’s production stabilizing effort comes as benchmark Brent futures hover near multi-year high around $80 a barrel.