Seismic Facies Analysis, 3D Horizon Mapping, Source and Reservoir Rock Characteristics of the Paleocene Sequence in Potwar Basin, Pakistan: with Emphasis on Petroleum Potential Prospect

Abstract

Abstract —This study presents a comprehensive analysis of the Balkassar oilfield in the Potwar Basin, Pakistan. It integrates seismic reflection data, a 3D subsurface horizon model, and geochemical and petrophysical data. Evaluating the Lockhart Formation’s geochemical properties using well cuttings reveals consistent patterns of relatively low to fair total organic carbon (TOC). S2 values suggest a fair generation potential with a mixed Type II–III kerogen composition. Seismic facies analysis identifies five distinct categories with parallel attributes. Horizons from lower Permian to Eocene show varying amplitudes and prevalent parallel to wavy internal configurations. Geometries, mainly sheet-to-wedge, enhance stratigraphic understanding. The 3D seismic interpretation reveals the Lockhart Formation’s structural traits, with pronounced northwest dip and gentler southeast inclination. Faults flanking the formation truncate its limbs. A significant contour closure in the northwest, confined by fault boundaries, signifies attractive hydrocarbon potential. Petrophysical analysis indicates an average 9.17% porosity. Dominated by limestone, the formation shows average water saturation of around 25.29% and hydrocarbon saturation of roughly 74.71%, indicating favorable reservoir properties. The Lockhart Formation holds promise as a reservoir rock within the Potwar Basin, though its source rock suitability is limited. This study enhances understanding of Balkassar’s geological complexities and contributes to knowledge of hydrocarbon exploration in the Potwar Basin.