Abstract

Bassein Formation of Middle to Late Eocene is a prolific carbonate reservoir within the Heera– Panna–Bassein (HPB) sector of India's western offshore basin. In Mukta and Panna fields this Bassein formation exhibits considerable heterogeneity in porosity and reservoir quality. Despite sustained hydrocarbon production, development in these fields is challenged by the complex interplay of depositional architecture, structural configuration, and diagenetic overprints. These geological complexities hinder accurate prediction of reservoir facies, porosity distribution, and fluid flow behaviour, which are critical for efficient field development and hydrocarbon recovery. Conventional depositional models often fail to explain the heterogeneities of carbonates of Bassein Formation. To overcome these limitations, a more holistic and integrated approach is essential, one that incorporates high-resolution seismic inversion, detailed well log interpretation, sedimentological analysis and critically, the influence of diagenetic fluids in shaping reservoir architecture. This study bridges that gap through a comprehensive workflow leveraging 4C-3D OBN seismic data, advanced petrophysical analysis, PP-PS joint inversion, and GR-PIGN detrending techniques to construct a geologically robust and spatially refined reservoir model across the Mukta and Panna fields. The objective is to accurately predict reservoir sweet spots, understand porosity distribution and porosity evolution, and assess the impact of diagenetic processes on reservoir performance. The outcomes of this study aim to enhance reservoir characterization, guide development strategies, and reduce uncertainty in future exploration and development activities within the structurally and stratigraphically complex Panna and Mukta fields.