Unveiling the Geological Mysteries: Tectonics, Evolution, and Hydrocarbon Play Types of the Andaman–Nicobar Basin from Seismic Data

Abstract

The Andaman–Nicobar Basin, located at the convergent margin between the Indian and Eurasian plates, is one of the most tectonically dynamic and geologically complex frontier basins in the northeastern Indian Ocean. Utilizing over 23,500-line kilometers of newly acquired 2D seismic data (2021–2023) integrated with legacy datasets and well information, this study redefines the basin’s tectonic framework, stratigraphic evolution, and hydrocarbon potential. Seismic interpretation delineates a classic arc–trench–backarc system comprising the Andaman Trench, accretionary prism, volcanic arc, and backarc spreading centers, reflecting ongoing subduction and extensional tectonics. Paleo-flattening and facies analyses reveal a multi-phase evolution involving initial rifting in the Late Eocene–Oligocene, post-rift marine transgression with carbonate platform development, and Miocene to Recent inversion related to India–Eurasia collision. Four key hydrocarbon play types are identified: syn-rift clastic, early post-rift carbonate, early post-rift clastic, and late post-rift clastic systems, with reservoir porosity ranging from 12% to 25% and thickness up to 2.5 km. This work refines earlier tectono-stratigraphic models by delineating new structural highs, spreading centers, and untested plays in forearc and western backarc sectors. The results highlight promising exploration potential, particularly within early post-rift carbonate and late post-rift clastic plays, offering a robust framework for future hydrocarbon exploration in this frontier basin.