Oil and Natural Gas Corporation (ONGC)on Thursday posted a 64.8 per cent jump in third-quarter profit, handily beating analysts estimates, boosted by higher revenue from offshore operations.ONGC's profit stood at Rs 8,263 crore($1.16 billion) in the quarter ended December31, compared with Rs 5,015 crorerupees a year earlier, the oil and gas explorer said in a stock exchange filing.Analysts on average had expected a profit of Rs 7,371 crore, according to Refinitiv data.Revenue from operations climbed over 20 per cent to Rs 27,694 crore, while revenue from offshore operations rose 19.1 per cent, ONGC said.