"Our market position as the largest producer of CBM in Australia is now significantly enhanced," said Origin Energy executive general manager of exploration and production, John Piper.

According to OCA's parent company Origin Energy, this acquisition provides further initial interests of 17.1% in the Fairview Project, 18.25% in the Durham Project and 0.91% in the Durham Transfield Project.

"In combination with OCA's current interests, the company's final equity interests will be 25.5% in the Fairview Project, 54.2% in the Durham Project and 77.1% in the Durham Transfield Project," said Origin.

"As a result of this transaction, OCA will book a further 170 petajoules of 2P reserves across these areas of interest."

OCA first acquired CBM interests in Queensland in 1996 and has since developed the Moura and Peat fields (OCA - 100%) that produce approximately 25 terajoules per day. OCA acquired its initial interest in the Fairview field last year.

In February, OCA acquired major interests in the Fairview and Durham CBM projects and in exploration permits over the Walloon Coal Measures areas of the Surat Basin in central Queensland for $49.2 million.

Origin said that the sale and purchase agreement is now subject to due diligence and requisite approvals under the Queensland Petroleum Act.