National Seismic Programme mapped 46,960 line km, supported 11 awards

National Seismic Programme (NSP) completed about 46,960 line km of two-dimensional, or 2D, seismic data acquisition, processing and interpretation after beginning in September 2016. The government reports that 11 exploration blocks were awarded from areas appraised by NSP: seven in Rajasthan, two in Mahanadi and two in Assam Shelf.

What did NSP complete across India’s sedimentary basins?

NSP completed approximately 46,960 line km of 2D seismic acquisition, processing and interpretation across Category-I, Category-II and Category-III basins. The Central Sector Scheme was launched by the Ministry of Petroleum and Natural Gas to appraise onland sedimentary-basin areas where geological and geophysical data were absent or limited, creating a base for future exploration and production, or E&P, activity.

India has 26 sedimentary basins spanning 3.36 million square kilometres across onland, shallow-water and deep-water areas. NSP specifically addresses the onland appraisal need, while appraisal of unappraised offshore areas up to the Exclusive Economic Zone, or EEZ, and drilling of parametric wells are being taken up separately. The EEZ is the maritime area in which India has designated rights for economic activity.

The 46,960 line-km total is a data-generation measure rather than a discovery or production measure. Under NSP, the survey information is intended to identify prospective areas and support the carving out of blocks under the Open Acreage Licensing Policy, or OALP. That linkage matters because a prospective geological lead must still move through block definition, bidding and contract award before an operator can undertake exploration.

How was NSP’s 46,960 line-km mapping distributed?

Category-III basins accounted for 24,280 line km in the listed NSP programme, or 51.7% of the 46,961 line km obtained by adding the basin entries. Category-I entries total 10,448 line km and Category-II entries total 12,233 line km; the one-line-km difference from the reported approximate total reflects the source’s use of “about 46,960” line km.

Deccan Synclise received 10,436 line km, the largest amount among all named basins, while Vindhyan received 5,373 line km and Assam Shelf & Assam Arakan received 5,246 line km. At the smaller end of the listed programme, Kaladgi received 257 line km and Andaman 264 line km. These differences show that survey coverage was not evenly allocated across the 21 named basin entries.

Coverage included Cambay at 1,469 line km, Krishna-Godavari at 981 line km and Rajasthan at 2,752 line km in Category-I. Category-II coverage included Kutch at 1,809 line km, Mahanadi at 2,481 line km and Saurashtra at 2,306 line km, while Category-III coverage included Ganga-Punjab at 3,858 line km, Narmada at 1,618 line km and Chhattisgarh at 1,778 line km.

How did NSP mapping support exploration-block awards?

NSP mapping supported 11 awards because the programme’s appraised areas supplied information that could be used to identify prospective acreage and carve out OALP blocks. Rajasthan accounted for seven of the 11 awarded blocks, or 63.6%, while Mahanadi and Assam Shelf accounted for two blocks each. The disclosed awards are a measure of conversion from NSP-appraised areas into contracted exploration acreage, not proof of hydrocarbon discoveries.

The conversion mechanism is the OALP process. An investor studies geological and geophysical data held in the National Data Repository, submits an expression of interest for an area, and the resulting block is finalised and invited for bids before a contract is awarded. NSP data are available for E&P stakeholders to view from anywhere in the world through the National Data Repository, allowing an assessment of a block’s prospectivity before bidding.

This use of centralised data fits within a wider national appraisal effort. India’s sedimentary basins have 12.0 billion tonnes of oil equivalent of discovered petroleum and 12.9 billion tonnes of oil equivalent of undiscovered risked potential, according to the basin overview. The 12.9-billion-tonne estimate exceeds the discovered volume by 0.9 billion tonnes of oil equivalent, but it is described as risked potential rather than a discovered resource.

What technical and national coverage changes does NSP reveal?

NSP’s long-spread surveys, using spreads of 12 to 18 km, improved understanding of tectonic framework and identified sub-trappean Mesozoic sediments in some areas. Sub-trappean refers to sediments beneath volcanic trap formations, while Mesozoic identifies a geological era. The disclosed result is that the data provided leads concerning possible extensions of existing producing basins.

NSP sits alongside a broader effort that has brought 79.5% of India’s basin area under appraisal sufficient for meaningful subsurface analysis. The national basin overview says four stratigraphic wells are planned to improve understanding of hydrocarbon play systems, and all forms of hydrocarbon resources are being drawn up for reassessment through expert consultancy. A stratigraphic well is a well drilled to obtain geological information rather than necessarily to develop a known field.

The scope also distinguishes conventional from unconventional resources. The basin overview identifies unconventional forms including coal seam gas, shale plays, tight plays, basement fractures and gas hydrate, while its 12.0-billion-tonne discovered and 12.9-billion-tonne undiscovered estimates refer to conventional petroleum occurrence. This distinction means NSP seismic coverage can improve subsurface understanding without itself establishing the commercial viability of any resource type.

Conclusion

NSP’s reported achievement is the completion of about 46,960 line km of 2D seismic work since its September 2016 start, with the listed Category-III allocation of 24,280 line km exceeding the other two basin categories. Its practical policy outcome so far is narrower but concrete: 11 exploration blocks have been awarded from appraised areas, concentrated in Rajasthan with seven awards.

The next evidence to watch is the disclosed plan for four stratigraphic wells and the continuing reassessment of hydrocarbon resources through expert consultancy. Whether the mapping continues to translate into exploration activity depends on investors using National Data Repository data, submitting expressions of interest under OALP and winning blocks through the bid process.