"The discovery is significant as this play fairway is expected to open more oil pool areas, leading to better hydrocarbon potential within the block," it said.

The 635-sq km CB-ONN-2003/1 block is located at a distance of about 130 km from Ahmedabad, in Gujarat. "This discovery, named Dhirubhai-47, the fourth oil discovery in the block so far, has been notified to the government and Director-General, Directorate General of Hydrocarbons," the statement said.

"The potential commercial interest of the discovery is being ascertained through more data gathering and analysis," it said. The block covers an area of 635 sq km in two parts - Part-A and Part-B. RIL, as operator, holds 100 per cent participating interest in the block. The discovery well, CB1-A-F1, was drilled to a total depth of 1,605 metres in Part-A of the block.

While the entire block area has been covered with 2D seismic, about 80 per cent of the block area has 3D seismic coverage. Of the 14 exploratory wells drilled in the block by RIL so far, 10 of them are located in Part-A and the remaining four are in Part-B of the block.

"RIL is continuing further exploratory drilling efforts in the blocks," the statement said. "This discovery supplements RIL's understanding of the petroleum system in the Cambay Basin in general and this block in particular," it added. Based on interpretation of the acquired 3D seismic data, several more prospects with upside potential have been identified at different stratigraphic levels, RIL said.