Abstract

The paper documents the evidence of syn-rift sedimentation within the Late Paleocene to Early Eocene Panna Formation in the North Tapti area, Western Offshore Basin. Most wells in this region target structural highs where syn-rift deposits are limited. Significant syn-rift sedimentation is predominantly preserved within structurally controlled depocenters and halfgrabens. In the study area, spatially discontinuous distribution of syn-rift deposits and absence of laterally persistent seismic horizons create substantial challenges in establishing stratigraphic correlations of syn-rift sediments within the Panna Formation. These complications are further compounded by the overprinting effects of erosion which often obscure the characteristic seismic signatures of syn-rift. To overcome these constraints, an integrated multidisciplinary approach combining 2D seismic data interpretation, well-log analysis, and sedimentological studies of conventional and sidewall cores was employed to provide the foundation for this study. The detailed analysis reveals that syn-rift facies comprise predominantly trap conglomerates and trap wacke deposited through high-energy, gravity-driven mass-flow processes along tectonically active margins. These facies transition into claystones and shales basinward, reflecting deposition under lower-energy settings. This lithological variation is welldocumented through progressive changes in seismic reflection patterns that reveal characteristic syn-rift signatures such as classic wedge-shaped geometry, onlap termination and chaotic reflector configuration. These seismic features also correlate closely with distinctive log responses observed in gamma-ray and resistivity curves.