Reliance Industries Ltd has reported a new commercial natural gas find in the shallow waters of the Mahanadi basin off the Orissa coast.

The find is estimated to be about four times bigger than the Hazira field of Oil and Natural Gas Corporation in Gujarat, which had reserves of 0.7 trillion cubic feet of gas before it started production.

Officials confirmed that the RIL had submitted a preliminary report that it had struck commercial gas in NEC-OSN-97/2 exploration block. RIL operates this block, with Niko Resources holding 10 per cent participatory stake in it.

Refusing to divulge any details, officials in the petroleum ministry said the company was asked to validate its claims. But RIL sources said about 2.5 trillion cubic feet of commercial gas had been reported in the block.

When contacted, a company spokesperson declined to comment but said RIL's partner Niko had made statutory announcements to this effect for its shareholders abroad. The announcement did not give details of estimates stating that they were premature.

Commercial natural gas or crude oil, against in-place reserves, is the quantity that can be commercially produced from a field.

Industry experts said normally about 70-80 per cent of in-place reserves translated into commercial production. The figure varied depending on difficulties encountered in production or the quality of gas or oil, said an expert.

"The company has been asked to submit a 'commerciality' report which can be prepared by its own consultants or independent consultants," said a senior functionary of the directorate-general of hydrocarbons, the regulator for the oil and gas exploration sector. The functionary refused to speculate on the potential of the find.

An authentic estimate could be made only after the DGH vetted the report on commercial viability, he added.

RIL had had earlier struck natural gas in a deepwater block in the Krishna Godavari basin off the Kakinada coast in Andhra Pradesh. Commercial production from this block is estimated at 7 trillion cubic feet, likely to be available from mid-2007.

The Reliance-led consortium had drilled six wells in the block, according to the requirements of a production-sharing agreement with the government. The company is required to submit reports to the DGH at every stage of development.