Petroleum Reservoir Potential of Cretaceous Siliciclastic Rocks of Tando Allahyar Field, Lower Indus Basin, Pakistan: Inferences from Petrophysics, Sequence Stratigraphy and Paleogeography

In this study, an investigation is conducted in Pakistan’s Lower Indus Basin, focusing on oil and gas exploration, reservoir characterization, and properties linked to the Tando Allah Yar (TAY) gas field. This study aimed to assess the petroleum potential of TAY field reservoir rocks using wireline logs. In this study, the Lower Cretaceous Goru Formation (LGFCT) was used to calculate the petrophysical properties of shale volume, effective porosity, water saturation, oil and gas saturation, permeability, water volume and oil and gas pore volume using logging data. The research also examined the sequence stratigraphic framework, using the GR log response to identify para-sequences and depositional environments amid changing sea levels. Results showed the LGFCT, with clean sandstone having 15% average porosity and permeability of 7–14 mD. Deep resistivity analysis indicated 30–45% water saturation and 55–70% oil and gas saturation across the three wells. Neutron porosity hydrogen index (NPHI) and density (RHOB) cross plots revealed the sandstone reservoir’s lithology, primarily 60–90% clean sand reservoir. The sequence stratigraphic analysis highlighted fluctuating sea levels, diverse lithology, and distinct para-sequences, including progradational, retrogradational, aggradational, and aggrading sequences, with a maximum flooding surface (MFS). Overall, findings suggest ample exploration potential, warranting a comprehensive evaluation of this promising prospect.