The newer gas finds will help turn the tide for ONGC, which has seen oil and gas output stagnating in recent times.
"Natural gas production will rise from about 65 mmscmd currently to over 100 mmscmd in 2017-18," ONGC's new Director (Offshore) Tapas Kumar Sengupta said here.
The incremental output will come from fields off both east and west coast.
ONGC's western offshore C-Series gas fields of C-24 and C-26 as well as Daman will produce 10 mmscmd. Another 7 mmscmd will come from GK-28/42 fields. He said another 30 mmsmcd from eastern offshore KG-DWN-98/2 fields and the neighbouring G-4-6. The C-Series gas field has proved to be more prolific than previously predicted, he said.
The reserves of 30 billion cubic meters have been upgraded to 130 bcm because drilling in some of the eight structures in the C-Series field has yielded more gas.
The fields, which currently produce 3 mmscmd, will double output this year and another 7 mmscmd would be added when the Daman structure in the field starts output in 2016.
ONGC's showpiece KG-DWN-98/2 block off the east coast, which sits next to the KG-D6 gas discovery area of Reliance Industries, would start production by 2017-18, he said.
ONGC plans to use RIL's KG-D6 infrastructure to bring the discovery in the Krishna Godavari basin to production.
Economic and technical feasibility of laying a pipeline to carry gas from the field to RIL's offshore gas gathering station and then to its landfall facilities at Gadimoga near Kakinada is being studied.
ONGC in July last year had signed a memorandum of understanding with Mukesh Ambani-run RIL to explore the possibility of sharing the east coast infrastructural facility.
If successful, the same concept will be considered for the nine gas discoveries in ONGC's KG block KG-DWN-98/2, which sit next to Reliance's flagging KG-DWN-98/3 or KG-D6 block.
Instead of setting up separate gas processing and transportation facilities, ONGC is looking to hire RIL's under-utilised gas gathering station at KG-D6 along with pipelines to take the fuel to land as also its processing plant at Kakinada in Andhra Pradesh.
Reliance's pipelines and other facilities are capable of handling gas output of 80 mmscmd. Output at KG-D6 has dipped to below 14 mmscmd from 69 mmscmd in March 2010 and the company has indicated it may never touch 80 mmscmd due to unexpected geological complexities.