"The increase in profit is due to higher crude throughput, better refinery margin, higher domestic market sales and inventory gains against inventory loss compared with the corresponding period of last year," HPCL chairman and managing director Mukesh K. Surana said.

Net profit in July-September at Rs 1,735 crore was 147 per cent higher than Rs 701 crore in the same period a year ago, Surana said.

The company earned $7.61 on turning every barrel of crude oil into fuel in the quarter compared with $3.23 per barrel gross refining margin in the same period a year ago. "Throughput at both our refineries totalled 4.64 million tonnes compared with 4.04 million tonnes last year."

Also, the company reported an inventory gain of Rs 792 crore in the quarter compared with an inventory loss of Rs 550 crore. Inventory gain accrues when a refinery buys crude oil at a particular price but by the time it is able to process it and turn it into fuel, the rates have gone up, helping it to get a higher price.

Gross sales increased to Rs 54,153 crore during July-September from Rs 47,750 crore in the same period last year. Domestic sales of petroleum products increased 4.6 per cent to 8.37 million tonnes with petrol sales rising 7.1 per cent and diesel, 4.4 per cent.