The third well, CLPL-Dorado North 1- 82K/1 was plugged and abandoned as a dry hole on 14 December, 2011.
Rahul Dhir, chief executive of Cairn India, said the firm had acquired additional 3D seismic in a 600 square kilometer area and entered a "second phase of exploration".
A "potential commercial interest notification" has been submitted to Sri Lankan authorities under its agreement with the country, Dhir said in a quarterly review.
Typically, an oil firm will dig exploration wells and following further seismic tests will drill an 'appraisal well" to find flow rate of hydrocarbon and extent of the deposit and determine the commercial viability of a discovery.After a find has been declared to be commercially viable, actual production wells will follow.
An official at Sri Lanka's Petroleum Development Secretariat said the firm had indicated that there was commercial potential in their discoveries but an appraisal report has not yet been given.
Dhir said seismic data "will firm up several promising leads and prepare the operator for further exploration drilling in mid-2013."
The firm had tendered for a drill ship to conduct further exploratory drilling involving one firm well and three optional ones.