Abstract

The Early Oligocene Mahuva Formation (TaptiDaman, Mumbai Offshore Basin) is a critical yet complex petroleum reservoir, where traditional seismic imaging struggles to resolve intricate tidal depositional architecture and its impact on reservoir quality. This study integrates highresolution sedimentological and biostratigraphic analysis of 30 conventional and 34 sidewall cores from 17 wells to overcome these limitations and define the reservoir's genetic framework. We uniquely delineate nine lithofacies within a tidedominated delta system, reconstructing the evolution from transgressive (TST - Lower Mahuva) to highstand (HST - Upper Mahuva) systems tracts. Crucially, our analysis identifies and characterizes distinct tidal bar complexes (Facies Associations F2-F4) as the primary reservoir units. While diagenesis (cementation, authigenic clays) locally degrades quality, these bar sands exhibit excellent reservoir potential due to favorable geometry, moderate-good sorting, and enhanced porosity (8-18% based on core-log integration), particularly in proximal northern areas (e.g., Wells L, M, Q). This study explicitly maps and correlates these high-quality bar complexes across the field, demonstrating their control on reservoir distribution and performance. These findings provide a robust depositional model essential for targeting undrilled bar crests, optimizing well placement, and improving volumetric estimates, directly reducing exploration risk and enhancing development efficiency in the Mahuva play.