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173-13 The role of paleoenvironmental factors in assessing unconventional hydrocarbon potential of Early Cretaceous shales in the Lower Indus Basin, Pakistan

Session: Geologic Energy Resources and Storage for Now and the Future

Presenting Author:

Adeeb Ahmed

Authors:

Ahmed, Adeeb¹, Khan, Tahseenullah², Mustapha, Khairul Azlan³, Jahandad, Samina⁴, Khan, Muhammad Asif⁵

(1) Department of Earth and Environmental Sciences, Bahria School of Engineering and Applied Sciences, Bahria University, Islamabad 44000, Pakistan, (2) Department of Earth and Environmental Sciences, Bahria School of Engineering and Applied Sciences, Bahria University, Islamabad 44000, Pakistan, (3) Department of Geology, Faculty of Science, Universiti Malaya, 50603, Kuala Lumpur, Malaysia, (4) Hydrocarbon Development Institute of Pakistan (HDIP), Islamabad 44000, Pakistan, (5) Department of Earth and Environmental Sciences, Bahria School of Engineering and Applied Sciences, Bahria University, Islamabad 44000, Pakistan,

Abstract:

The Early Cretaceous Sembar Formation in the Lower Indus Basin, Pakistan, is recognized for its source rock potential and offers a unique opportunity to study the role of paleoenvironmental factors in assessing unconventional hydrocarbon potential. This study employs a multi-analytical approach that integrates organic geochemistry (including screening and detailed hydrocarbon analysis), inorganic geochemistry (XRF and XRD), physical core examinations, and mineralogical characterization (thin-section and SEM analysis). The objective of this integrated approach is to reconstruct the paleo-depositional environment, evaluate organic carbon accumulation mechanisms, and examine unconventional hydrocarbon potential. The results reveal that the Sembar Formation has fair to excellent source rock potential. The dominant type III kerogen, along with a minor presence of type II and higher maturity, suggests potential for both shale gas and shale oil production. The Sembar shales are classified as siliceous mudrocks, reflecting a rift tectonic setting, with sediments primarily derived from intermediate igneous rocks. Favorable organic matter accumulation occurred under warm humid climates, moderate terrigenous influx, higher paleobathymetry, and increased hydrothermal activity. These shales were preserved under suboxic to intermittently anoxic marine conditions. The Sembar Formation is composed of siliceous shales, exhibiting optimal brittleness and porosity, which supports its suitability for hydraulic fracturing. In conclusion, the Sembar Formation provides favorable conditions for organic carbon accumulation, with significant sweet spots for shale gas and oil production. These findings enhance our understanding of the interplay between paleoenvironmental factors and organic carbon preservation, highlighting the unconventional hydrocarbon potential of the Lower Indus Basin and offering insights for global exploration, especially in rift tectonic settings and organic-rich shale formations.

Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-8662

The role of paleoenvironmental factors in assessing unconventional hydrocarbon potential of Early Cretaceous shales in the Lower Indus Basin, Pakistan

Description

Session Format: Oral

Presentation Date: 10/21/2025

Presentation Start Time: 11:15 AM

Presentation Room: HBGCC, 302C

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