The discovery, in the deepwater block CY-DWN-2001/2 (CYD5), is situated 62 kilometers from the coast in the Cauvery Basin and is the second gas discovery in the block, the companies said in a statement.
RIL is the operator of the block with 70 percent interest and BP has a 30 percent share.
"Well CYIII-D5-S1 was drilled in a water depth of 1,743 meters, to a total depth of 5,731 meters, with the primary objective of exploring Mesozoic-aged reservoirs,” it said.
"Preliminary evaluation of well data and fluid samples indicated presence of gas condensate in the reservoir interval with a gross column of 143 meters," it added.
The well reached its total depth in early August and RIL has conducted drill stem test (DST) to evaluate the potential of the discovery.
"The well which had the initial reservoir pressure of 8,000 psi flowed gas at the rate of 35.2 million standard cubic feet per day with condensate," the statement said.
The government and Directorate General of Hydrocarbons have been notified of the discovery, which has been named D-56.