Sharara can contribute an additional 300,000 barrels a day, the officials said. Its initial output was 27,000 barrels a day as of Sunday. Output at the field has been shut almost continuously since early January—except for a short resumption in June. The slow return of Libya’s shutdown production has already put downward pressure on oil prices, and is a consideration in a debate in Saudi Arabia over whether to boost production from next year . Libya, one of the worlds biggest producers, pumped some 1.3 million barrels a day before the standoff forced officials to shut down production. Write to Benoit Faucon at benoit.faucon@wsj.com