Not just Andaman: After fresh gas finds, India expands oil and gas hunt along east coast

With Oil India striking natural gas in the Andaman Sea for the second time in recent months, India is intensifying efforts to discover new oil and gas reserves along its eastern offshore frontier, reported CNN-News18

As part of this push, the government is launching a major programme to reprocess decades-old seismic data and conduct fresh deep-water surveys across some of the country’s most promising sedimentary basins, CNN-News18 reported.

The initiative covers the Mahanadi, Bengal-Purnea, Cauvery and Krishna-Godavari (KG) basins. The government has invited bids from global geophysical firms to reprocess legacy 2D and 3D marine seismic datasets using advanced imaging technologies, followed by new broadband 3D seismic surveys under the Multi-Client model. The programme is expected to be completed over 36 months.

Reducing Import Dependence

The move forms part of India’s broader strategy to reduce dependence on imported crude oil and natural gas by unlocking untapped hydrocarbon resources beneath the seabed.

By applying modern imaging techniques to older seismic datasets, authorities hope to generate clearer subsurface images, identify previously overlooked geological structures and refine prospective drilling targets ahead of future licensing rounds.

Officials said the exercise aims to create integrated seismic volumes for each basin, improve geological models and identify new play fairways and hydrocarbon leads. Newly acquired seismic data will also be incorporated into the interpretation process to continuously enhance understanding of subsurface geology.

Why the East Coast Matters

The focus on the east coast is significant, as several of these basins have either yielded major discoveries in the past or are believed to hold substantial undiscovered resources.

Mahanadi Basin

The Mahanadi Basin, classified as a Category-II basin with discovered hydrocarbons but limited commercial production, is regarded as one of India’s key frontier deep-water regions.

Situated off the Odisha coast, it is considered geologically analogous to the prolific Bengal Offshore Basin and hosts multiple hydrocarbon plays ranging from the Pliocene to the Cretaceous period. Thick sedimentary sections extending beyond 8 km in depth and deep-water reservoirs are viewed as offering significant exploration potential.

Bengal-Purnea Basin

The Bengal Offshore Basin contains sedimentary sequences exceeding 10 km in thickness, largely deposited by the Ganga-Brahmaputra river system.

Geological studies indicate the basin may host significant Miocene-age hydrocarbon accumulations, while biogenic gas indications have already been reported. The adjoining Purnea sub-basin is considered prospective for hydrocarbons trapped within Gondwana-age formations.

Cauvery Basin

The Cauvery Basin, which extends offshore from Tamil Nadu into the Bay of Bengal and the Gulf of Mannar, is already a proven petroleum-producing region.

However, officials believe sizeable resources may still remain undiscovered, particularly in deeper Jurassic syn-rift plays, fractured basement reservoirs and offshore carbonate systems. Sedimentary thicknesses in parts of the basin reach nearly 8 km, with the deepest exploration targets located between 7,000 and 8,000 metres below the surface.

Krishna-Godavari Basin

The Krishna-Godavari Basin, India’s most prolific east-coast gas province, remains central to the country’s energy ambitions.

The basin hosts multiple producing gas fields and features a complex petroleum system comprising deep-water turbidites, basin-floor fans, fault-controlled Mesozoic reservoirs and gas hydrate occurrences.

Multi-Client Model to Speed Up Exploration

The Multi-Client model is expected to accelerate exploration activity by allowing geophysical companies to invest in data acquisition and later market the datasets to multiple energy firms.

This reduces the government’s upfront costs while making high-quality geological information available to potential investors.

A Major Bet on Future Discoveries

Taken together, the surveys represent one of India’s most ambitious recent efforts to upgrade subsurface intelligence across its eastern offshore basins.

With energy demand continuing to rise and import dependence remaining high, New Delhi is betting that improved seismic imaging today could pave the way for the next generation of domestic oil and gas discoveries.