"Assuming natural gas sales volume of around 10 billion cubic meters for the first six months of 2018-19 for ONGC and its joint venture partners, ONGC's natural gas revenue will increase 23 per cent to Rs 8,000 crore for the six months between April 1 and September 30, 2018, from a reported Rs 6,500 crore the year before," Moody's said in its credit outlook.

Natural gas contributed around 45 per cent to ONCG's crude oil and natural gas production volume in 2016-17.

"The gas price for H1 FY2019 (first half of 2018-19) though higher than H2 FY2018 continues to remain low at an absolute level. Accordingly, gas production remains either a break-even or a loss-making proposition for most fields for the upstream producers notwithstanding some decline in oil field services or equipment cost.

"Additionally, the appreciation of the Indian rupee against the dollar in 2017-18 also dampens the realisations of the gas producers," K. Ravichandran, senior vice-president at research and ratings agency Icra said.

ONGC's natural gas production increased 6.46 per cent to 21,416 million standard cubic meter (mmscm) in April-February 2017-2018 from 20,116 mmscm in the corresponding period of the previous fiscal.

The ministry also raised the gas price ceiling for output from deepwater, ultra deepwater and high pressure-high temperature areas to $6.78 per mBtu an increase of 7.6 per cent over $6.30 per mBtu during October-March 2017.