ONGC said it discovered "very high quality" oil at the Vanaduru South No. 1 exploration block in Andhra Pradesh state.
A "high potential discovery" was made in the KG shallow offshore basin, which the company said was "a significant boost to ONGC's efforts towards attaining critical hydrocarbon volumes for viability of a possible 'cluster based development' for the block."
A third discovery was made in eastern Tripura state.
ONGC didn't give a reserve estimate of any of its discoveries.
India relies heavily on imports to meet crude oil demand. It's the fourth-largest energy consumer behind the United States, China and Russia.
The U.S. Energy Department's Energy Information Administration estimates India's proven oil reserves at the end of 2012 at 5.5 billion barrels.
The country is one of the world leaders in terms of liquefied natural gas imports. It lacks the infrastructure needed to take advantage of any reserve potential.