Investigating Offshore Godavari Basin Morphotectonics using high-resolution seismic data

The Offshore Godavari Basin, located along the Eastern Continental Margin of India (ECMI)), is a major pericratonic rift basin and an important location for hydrocarbon industries. In this study, we analyse a 50-km-long 2D seismic profile, acquired by Oil and Natural Gas Corporation Limited (ONGC), from the KG-DWN-98/2 block within Godavari Basin. The profile traverses the continental shelf-slope transition, where seafloor water depth increases from ~100 m on the shelf to ~1.3 km in the slope region. The dataset comprises 861 air-gun shots, with each shot gather containing 955 traces. The shot spacing is 50 m, while the hydrophone group interval is 6.25 m, resulting in a CDP spacing of 3.125 m. We have processed the seismic data using a conventional workflow that included geometry merging, band-pass filtering, WEMA, CDP sorting, velocity analysis, NMO correction, Radon filtering, stacking, and post-stack time migration. Preliminary interpretation of the processed seismic section reveals a seafloor characterized by southward dipping uneven topography. A thick pile of sedimentary deposits overlie the southward dipping continental basement in which landward verging growth faults in the shelf region between CDPs 7000-15000 and large scale seaward verging thrusts in the slope region are developed from southern end of the profile to CDP-5000. A folded deposit composed of clay observed at TWT 5-6s of the slope region. The migrated section further illustrates shale diapirism wherein over-pressured shale rises through denser sedimentary deposits and uplifts the overlying formations, creating unique styled fault-bounded highs and anticlines. The process might have involved reactivation of the extensional faults at the basement, causing uplift of previously subsiding area. The study will finally sheds light upon the sea-level fluctuation and its relation with the sediment dynamics of the Godavari river and associated neotectonism.