Fracture Network Characterization in a geological complex considered for carbon dioxide (CO₂) injection in the offshore of the Lusitanian Basin

Abstract

This study investigates fracture network characterization in a geologically complex offshore sector of the Lusitanian Basin to evaluate its suitability for long-term carbon dioxide (CO₂) storage in deep saline aquifers (DSA). As Carbon Capture and Storage (CCS) becomes increasingly important for climate change mitigation, ensuring caprock integrity is essential to prevent CO₂ leakage and maintain storage security. Using the 3D Cabo Mondego seismic dataset as an analogue, the study performed fracture interpretation and statistical characterization of fracture systems within the sealing formation. Key fracture attributes—including length, height, orientation (strike and dip), aspect ratio, and fracture intensity—were analysed to assess fracture distribution and their potential influence on storage performance. The characterization framework enabled evaluation of possible leakage pathways and supported assessment of the feasibility and integrity of geological CO₂ storage under existing data constraints. Conducted within the scope of the PilotSTRATEGY project, this work contributes to improving understanding of fracture behaviour in deep saline aquifers and provides important input for modelling the long-term evolution and containment of injected CO₂ plumes in European storage sites.