MUMBAI: A joint venture led by Reliance Industries and BG Group has agreed to hand drilling infrastructure from an abandoned gas field to ONGC Ltd, their junior partner, helping the state-run group develop a large gas reserve nearby, two company sources said. Executives from Reliance, BG and ONGC signed an agreement in New Delhi on Tuesday night — providing respite in a months-long battle between the partners over the cost of closing the Tapti field off India’s west coast. The sources, with direct knowledge of the matter, declined to be named as they are not authorised to talk to the press. ONGC plans to invest around INR 100 billion to develop its key Daman field, which is next to Tapti. This deal will help the group keep a lid on costs.