The government has from time to time advised ONGC NSE -0.37 % to have partnerships in its major fields including Mumbai High and Bassein & Satellite assets off the west coast with a view to raising output and technology infusion, Parliament was informed on Thursday. In a written reply to a question in the Lok Sabha, Minister of State for Petroleum and Natural Gas Rameswar Teli said national oil companies are free to choose field-specific models including farm out (giving stake) and joint venture/technical service model for enhancing production from their matured and aging fields.