Reliance Industries' gigantic gas field in the Bay of Bengal holds reserves much lesser than previously estimated.

Global independent reservoir certifying agency DeGolyer and MacNaughton has admitted to making an arithmetical error in the March 31, 2003 reserve report for RIL's D6 Block in Krishna Goadavari Basin that put the in-place gas reserves at 10 trillion cubic feet. It now estimates the gross in-place gas reserves in the block at 8.6 tcf, sources said in New Delhi.

"A revised report effective March 31, 2003 was issued on November 12, 2003 by D&M, correcting the error. The revised report assigns gross in-place gas reserves of 8.6 trillion cubic feet, including 2.5 tcf proved, 3.4 tcf probable and 2.7 tcf possible," they said.

The D&M report does not include the results of A2 well -- the last of the eight wells drilled by RIL in the first phase of exploration -- whose evaluation was in progress at the time of the report. The A2 well had encountered 190 meters of net gas pay and the well flowed 33.8 million cubic feet per day of dry, sweet gas.

Reliance, the operator of D6, had previously stated its KG-DWN/98/3 (Block D6), 26-km off the east coast, holds 14.5 tcf of reserves.

While Reliance spokesperson was not available for comments, senior company officials maintained the third party engineered numbers (reserves) would increase to 14 tcf over time through ongoing analysis, drilling and testing.

In its previous report, D&M had put proved gas reserves at 3.4 tcf, probable reserves at 3 tcf and possible reserves at 3.6 tcf. Like the latest report, these too were based on results of seven wells and did not include the results of A2 well, sources said.

Reliance Industries had earlier stated that its 8-well drilling programme had resulted in 14.5 tcf of gas reserves, equivalent to about 300 million tonnes of crude oil and capable of producing in excess of 60 million standard cubic meters of gas per day.

The company will do additional seismic surveys in December and plans new drilling in early 2004. The field development programme, which may cost $1.5 to $2 billion, is being prepared and first production is scheduled for July 2006, they said.

RIL holds 90 per cent stake in the 1.9 million acre deep-sea block, while the remaining is with Canadian Niko Resources.

Of the eight wells drilled so far in the block, four discoveries -- Dhirubhai-1, Dhirubhai-2, Dhirubhai-3 and Dhirubhai-4 have been announced.

The firm has declared gas find Dhirubhai-1 as commercial. It plans to recover at least 70 per cent of the estimated 4.1 tcf in-place gas reserves from the well. Dhirubhai-1 can produce 40 million standard cubic meters per day of gas in two years time.

Dhirubhai-2 is assessed to contain 0.16 tcf of reserves, Dhirubhai-3 3.5 tcf, while Dhirubhai-4, on a different structure 10-km away from the previous three finds, is estimated to have 1.7 tcf reserves.