This is the second such sale in recent months by Tata Petrodyne. The first sales was in another Cambay basin field CB-OS/1 to US company Enron Oil and Gas. The stake of the Tata firm in CB-OS/2 will come down from 45 per cent to 15 per cent once the deal is through. Cairn Energy already has a 45 per cent holding which will increase to 75 per cent. The remaining 10 per cent is with Oil and Natural Gas Corporation (ONGC).

``We are in the process of increasing our presence in the CB-OS/2 block to 75 per cent, by acquiring 30 per cent equity from Tata Petrodyne,'' Cairn Energy Pte Ltd (CEPL) executive director Bruce McCarthy said.

A Tata spokesperson confirmed this adding, however, that the sale proposal was still being negotiated and the deal needed to procure all the necessaryofficial approvals. The spokesperson said the deal would involve the transfer of all exploratory rights in CB-OS/2 to CEPL.

McCarthy declined to divulge the financial aspects of the deal, saying it was premature to do so as several vital aspects were still being worked out. Asked how long it would take for the deal to be settled, McCarthy said it was difficult to predict as the country was going through an election process. ``Everything depends on the new government and its decisions,'' he said. CEPL has been in the country for several years now, its main project till date being the Ravva fields in Andhra Pradesh.