Public sector oil refiners have signed an agreement for setting up a joint venture refinery-cum-petrochemical complex on Wednesday. The refinery will be set up in Ratnagiri with a capacity of 60 million tonnes. Indian Oil Chairman Sanjiv Singh said that the company will hold 50 per cent stake in the joint venture project. Hindustan Petroleum and Bharat Petroleum will hold 25 per cent stake each. An official privy to the discussions said that the joint venture is in the process of acquiring 15,000 acres for the project. The project is expected to see $35-40 billion investment.