Characterization of fracture patterns in Lower Cretaceous platform carbonates: Examples from the Galve sub-basin (Iberian Chain)

Abstract

Summary The estimation of porosity and permeability in limestone successions is essential for reservoir characterization, both in terms of hydrocarbon production and also for Geo-Energy applications. Most carbonate reservoirs are highly fractured, and thus permeability is typically controlled by fracture networks. Outcrop analogues are widely used to understand, the characteristics of subsurface fracture networks and their evolution in time. This contribution presents a study of the orientation, intensity and distribution of fracture networks in the Barremian-Aptian succession, from the western Maestrat Basin in eastern Iberian Chain. The succession was studied through a combination of methods, including fieldwork analysis, rock sampling and quantification of fracture patterns from orthophotos and virtual models acquired with an unmanned aerial vehicle. This technique allowed the generation of photogrammetric models for the collection of a large number of fracture datasets. The results reveal that fractures are mainly arranged into orthogonal systems, dominant NW-SE and NE-SW orientations, respectively. Preliminary findings link the genesis of the fracture sets to the Early Cretaceous extension period affecting the Iberian Plate owing to the opening of the Bay of Biscay domain. This information can be used to characterize the fracture permeability, and the mechanical behavior of carbonate units from coeval subsurface hydrocarbon reservoirs.