Oil and Natural Gas Corporation has struck a large gas field in the Krishna-Godavari basin in Bay of Bengal, home for the gigantic gas find of Reliance Industries Ltd.

ONGC's in-house deep sea drill-rig Sagar Vijay encountered large gas bearing structures while drilling its maiden well in the G4-AB location, adjacent to RIL's gas bearing KG-DWN-98/3 block.

"The well is to be drilled to a depth of 2500 meters and gas indications have already been observed at a number of places in the interval of 1580-1720 meters," highly placed company sources said in New Delhi.
 
While the reserves have not yet been tested as the well is yet to reach its target depth, preliminary indications point to a potential of little less than a trillion cubic feet of gas.

Reliance had in 2002 struck 14 tcf of gas reserves in KG-DWN-98/3 block, off the Andhra Pradesh coast. Prior to that Cairn Energy of the United Kingdom had established one tcf of reserves in KG-DWN-98/2, south of RIL block.

Sources said Sagar Vijay spudded the well, north-west of RIL's 14 tcf find in KG-DWN-98/3, in November and is expected to reach the target depth next month.

ONGC, which has about a dozen exploration blocks in the highly prospective KG basin, will be deploying another deep sea drillship chartered from Transocean Inc of the United States in the basin next month.

Another charter deep sea drillship Belford Dolphin is drilling in the Gulf of Kutch in the Arabian Sea at location GKDW-CA-1.

Reserves in G4-AB, a block awarded to ONGC on nomination basis, would be ascertained by April, sources said.

Meanwhile, the drillship of Transocean will drill first well in KG-DWN-98/4 in late February.

"The KG-DWN-98/4 block, which was awarded to ONGC in the first round of bidding in new exploration licensing policy, too has good potential for gas reserve," they said.

KG-DWN-98/4 lies north-east of RIL's KG-DWN-98/3 block.