Karst Systems Controlled Reservoir Heterogeneity

Abstract Karst systems are key contributors to reservoir heterogeneity in carbonate formations across Abu Dhabi, often exerting significant influence on permeability, porosity, and overall reservoir performance. These karst features, ranging from millimetre-scale vugs to kilometre-wide sinkholes and collapse structures, are frequently encountered during drilling and production operations in formations such as the Mishrif, Laffan, Fiqa and other intervals on the reservoir scale. Despite their prevalence, karst features are not well-integrated into many subsurface models due to limitations in resolution, classification, and predictive understanding. This paper presents a new classification framework for karst systems, based on their structural and stratigraphic context, using integrated seismic, well log, and core datasets. Karst features are categorized into three dominant types: (1) Principal Deformation Zone (PDZ)-related karst formed along fault segments and pull-apart basins; (2) Slippage-related karst developed along bedding planes due to shear movement; and (3) Fracture corridor karst aligned with vertical or dilatational fracture systems. These systems are further characterized by their seismic signatures, diagenetic history, and impacts on hydrocarbon trapping and production. This study highlights the evolution of karst under both epigenic and hypogenic processes and proposes methods for early detection and risk mitigation. The evidence supporting the karst process are related to structural features associated. The resulting framework provides critical insights into karst-induced heterogeneity and supports improved field development planning, well placement, and production forecasting in complex carbonate reservoirs.