A review of silurian shale gas potential in North Africa’s paleozoic basins: geological framework, resource assessment, sustainability outlook

Abstract

North Africa hosts some great, prolific Paleozoic basins with significant shale gas potential, particularly within the Silurian “Hot Shale” formations. In this review, we assess the unconventional resource prospectivity of key North African basins by evaluating their organic richness, thermal maturity, and mineralogical composition, framing their development potential within a global context. By synthesizing published literature, industry reports, and geochemical datasets, this study identifies the key parameters controlling shale gas potential. The Rhuddanian, Ludlow Pridoli, and Frasnian Hot Shale intervals record total organic carbon (TOC) contents typically ranging from 2-14 wt%, with localized peaks exceeding 20 wt%. Kerogen is dominated by Type II/III mixtures, while vitrinite reflectance values indicate maturity levels spanning early oil to dry gas windows. Mineralogical analyses reveal substantial quartz and carbonate fractions, enhancing brittleness and hydraulic fracturing potential. Marked variability is observed across the basins, reflecting differences in depositional settings, structural evolution, and post-depositional thermal histories. The Ghadames and Berkine basins host the richest and most mature intervals, whereas the Jaffara and Chotts basins have less uniform successions. Beyond resource quality, environmental risks, including groundwater contamination, methane emissions, and induced seismicity, remain a key challenge. These challenges require basin-specific evaluation approaches that integrate standardized geochemical datasets, basin-scale petrophysical modeling, and real-time environmental monitoring to constrain resource quality and associated risks. Future development strategies may also incorporate carbon capture and utilization (CCU) within depleted reservoirs to reduce CO₂ emissions associated with shale gas exploitation. Future development should evaluate the effects of supercritical CO₂ (ScCO₂) solvent interactions on pore structure and mineralogy in shale, sandstone, and coal reservoirs to assess the spatiotemporal heterogeneity and suitability of carbon storage systems. Integrating these insights with reservoir-scale mapping and petrophysical modeling provides a basis for optimizing hydrocarbon recovery and long-term CO₂ storage in North African basins.