News: STO UPDATE 1-Australia's Origin Energy quarterly output revenue more than doubles

(Adds CEO comment; adds background on company's acquisition of Lattice Energy and export curbs)

Oct 31 (Reuters) - Australia's Origin Energy Ltd (ORG) said on Tuesday its quarterly gas production revenue rose 58 percent from a year ago, with increased output from the Australia Pacific liquefied natural gas (APLNG) project and higher gas prices.

APLNG shipped 32 cargoes in the quarter ended Sept. 30 and boosted production by 1.8 petajoules equivalent (Pje).

But the country's top power and gas retailer said total production and revenue were little changed from the prior quarter due to lower seasonal demand and a field decline at the Otway Gas Project joint venture with Toyota Tsusho Corp. Natural gas production was 89.1 PJe, compared with 89.2 Pje in the June quarter.

APLNG and its two rival LNG exporters on Australia's east coast, Queensland Curtis LNG, run by Royal Dutch Shell , and Gladstone LNG, run by Santos (STO), have come under pressure this year to step up gas supply to the domestic market from concerns about a shortfall and soaring prices.

The government had threatened to curb exports for east coast producers, but decided not to after the companies promised in September to sell more gas to that region.

To help meet that commitment, Origin last week agreed to buy 41 PJe of gas from APLNG over the next 14 months, raising the project's domestic sales to 186 PJe in 2018.

"APLNG is expected to provide almost 30 percent of total east coast gas market demand in 2018, as well as meet its export contract commitments," Chief Executive Frank Calabria said in a statement.

Revenue rose to A$678.6 million ($521.50 million) from A$429.7 million in the year-ago quarter, beating UBS' forecast of A$655 million.

During the quarter the company sold its natural gas unit, Lattice Energy, to Beach Energy (BPT) for A$1.5 billion ($1.2 billion) to reduce debt. As part of the deal it secured access to a portion of Lattice Energy's future production to support its domestic gas business.

Origin had taken on additional debt to build APLNG, which it said it would be trimmed to below A$7 billion by the end of its fiscal 2018, which ends in June. ($1 = 1.3012 Australian dollars)