State-run oil explorers ONGC and Oil India Ltd are planning to begin a Rs 3,200 crore stratigraphic drilling campaign in untapped offshore areas early next year, as part of efforts to discover new hydrocarbon reserves and cut reliance on imports, officials said.
In the first phase, four wells will be drilled in deepsea of Andaman, Mahanadi, Saurashtra and Bengal sedimentary basins.
Global energy giant BP will provide technical expertise in identifying the locations as well as drilling, officials said.
Stratigraphic drilling - also known as a stratigraphic test well - is a type of exploratory drilling aimed at studying underground geological formations rather than producing oil or gas. These wells are drilled to gather data on subsurface layers through continuous coring, petrophysical logging, and seismic data integration. The objective is to build a detailed geological profile to support future hydrocarbon exploration, without any immediate intent to extract resources.
This will help reach a decision if the area holds hydrocarbon resources that could be commercially produced.
"ONGC has stated that they have a rig and we hope to start drilling sometime in early 2026," an official involved in the process said.
The government has agreed to compensate Oil and Natural Gas Corporation (ONGC) and Oil India Ltd (OIL) for the cost of the stratigraphic drilling campaign. The Rs 3,200 crore estimated cost also includes a fee to be paid to BP for its services, officials said.
"The blocks (or areas) where the stratigraphic drilling is to take place is currently owned by the government and it alone will decide how any discovery has to be monetised - either through auctioning the area or giving it to a company or a consortium on a nomination basis," another official said.
It is unclear if BP would like to be part of the monetisation. "It is entirely possible that they demand a first right of refusal (ROFR) in any development - getting a predefined percentage of stake in any consortium that monetises a discovery. But nothing has been conveyed so far," the official said.
India imports almost 88 per cent of its oil needs and about half of its natural gas requirement. The government is keen to cut this USD 150 billion import bill by raising domestic production. One way of doing this is to find newer resources and the stratigraphic drilling is a step in that direction.
In a major step towards energy security, the government has reduced 'no-go' zones - areas previously restricted due to strategic interests like defence and space programmes - by 99 per cent, unlocking over 1 million square kilometres of India's Exclusive Economic Zone (EEZ) for oil and gas exploration.
To make deepsea exploration viable, the government has refined gas pricing formulas, allowing higher rates for resources produced from difficult areas.
In a bid to attract international exploration interest, India launched a Data Centre at the University of Houston in 2022 to showcase its sedimentary basin data. At the same time, the National Data Repository (NDR) was upgraded to a cloud-based platform, enabling seamless, self-service access to exploration data. Global energy giants like ExxonMobil and Chevron have since acquired Indian basin data, reflecting renewed confidence in the country's exploration and production (E&P) potential.
The Oilfields (Regulation and Development) Act was amended in March to introduce long-pending reforms and bring greater clarity to India's hydrocarbon sector. Key changes include a unified permit system covering both conventional and unconventional resources - such as shale oil/gas, coal bed methane, and gas hydrates - along with defined lease tenures and conditions. The amendments also protect investors from mid-term policy shifts, such as the introduction of new cesses or royalties.
Officials said a stratigraphic well may take as much as three months to drill and three to four quarters to interpret the results.
