New Delhi, Dec. 17 (PTI): The Oil and Natural Gas Corporation (ONGC) has made a huge gas find in the Krishna Godavari basin with initial estimates suggesting reserves of about 21 trillion cubic feet (tcf), and also struck a big gas field in the Mahanadi basin off Orissa coast.

ONGC, which had previously discovered 2-3 tcf of gas reserves in about half-a-dozen wells in the Krishna-Godavari basin block KG-DWN-98/2, struck a 28 metre net gas pay zone when deep sea drillship Belford Dolphin reached 5,300 meters depth at well UD-1, 55 km from the coast.

Separately, ONGC has struck an estimated 3-4 tcf of gas in block MN-OSN-2000/2 in water depths of about 1,200 metres, sources said.

They said ONGC has also found 15-20 million barrels of oil reserves in an Assam block.

The ultra-deepwater well UD-1 is yet to reach its target depth of 6,500 metres.