"We want to intensify our exploration activities," said Sahshi Shanker, director of technology and field services at ONGC.

"We are securing more and more rigs," Shanker said at the annual Platts Top 250 Global Energy Company Rankings.

Rig rates are down by 30-40% on the year and other exploration services rates are down by 40-50%, he said.

Industry sources at the gala event said more and more rigs were being laid off while services companies seeking new contracts at discounted rates.

According to Shanker ONGC is increasing its 2016 capital expenditure to about Rs 36,000 crores, up by about 10% from the current Rs 33,000 crore.

He pointed out that value of any exploration and production company increases through exploration activities. ONGC's intensified exploration is for the long-term growth.

Meanwhile, 14 Indian energy companies were listed in the 2015 Platts Top 250 Global Energy Company Rankings, a financial performance roster of publicly traded companies with assets greater than $5 billion.

With the first-time showing of National Hydroelectric Power Corporation LTD (NHPC) in the Top 250 Rankings, India scored a personal best in representation, with 14 energy companies on 2015 list, versus 13 a year ago.

India's top three energy companies in the 2015 list were Reliance Industries at 14th position, ONGC at 17 and Coal India at 38. Last year, these three corporations were positioned at 22, 21 and 47 in global rankings which are based on assets, revenues, profits and return on invested capital for the prior fiscal year.

Coal India was rated as the largest pure coal mining company in the world.

Others in the list were Bharat Petroleum Corp Ltd, Indian Oil Corp Ltd, GAIL (India) Ltd, Power Grid Corp of India Ltd, Hindustan Petroleum Corp Ltd, Cairn India Ltd, Essar Oil Ltd, Reliance Infrastructure Ltd, NTPC Ltd and Oil India Ltd.