A Geologically Consistent Permeability Model of Fractured Folded Carbonate Reservoirs: Lessons from Outcropping Analogue

Abstract

SUMMARYPresently adopted fracture-related permeability models of large folded reservoirs are simplistic and often unrelated to the geological setting and evolution of the considered structure. In order to improve predictions of fluid flow in more complex subsurface fractured reservoirs, we build a 3D fracture network model of an outcropping fold in Tunisia, and populate different structural domains with fracture data, collected from outcrops. Within the studied fold, we find large variations in deformation mechanisms between different formations, with the main mechanisms being Layer Parallel Shortening (LPS), resulting in regional deformation, and the more localized impact of fiber stresses and flexural slip. Within the steep flank of the anticline, we find that in one formation fracturing is mostly controlled by fiber stresses, whereas in the underlying formation flexural slip is the main deformation mechanism. These two formations are separated by a detachment surface. Using stress and strain fields, we aim at reconstructing the conditions at which these fractures have been formed. This can provide a better understanding of the relation between fracture patterns in different structural domains of a fold and the stress evolution that formed these fractures, and the subsequent impact of different fracture patterns on fluid flow in fractured folds.

Fracturing and fluid‐flow during post‐rift subsidence in carbonates of the Jandaíra Formation, Potiguar Basin, NE Brazil

“…Conjugate sets of hybrid fractures have been documented, for instance, from the Berda and Kef Eddour carbonate formation of Tunisia (Bisdom et al ., ). Here, sedimentary surfaces (pavements) steepened in association with the Alima anticline (e.g.…”

“…A few sub‐vertical stylolites perpendicular to the trend of the conjugate faults could also be documented despite being sometimes overprinted by other structures developed during anticline folding (e.g. Bisdom et al ., ).…”

A Novel Connectivity Metric of Identified Multi‐Cluster Fracture Networks in Permeable Formations

“…The new metric is implemented to analyze natural fracture networks automatically interpreted from various outcrop maps from different published works (80 in total) with a novel fracture detection algorithm, which are spread across different parts of the world and vary in scale from millimeters to kilometers (C. C. Barton, 1995; Bertrand et al., 2015; Becker et al., 2018; Bisdom, n.d.; Duffy et al., 2017; Gillespie et al., 1993; Healy et al., 2017; Holland et al., 2009; Jafari, 2011; N. E. Odling, 1997; N. Odling et al., 1999; Prabhakaran et al., 2021; Segall & Pollard, 1983; Thiele et al., 2017; Watkins et al., 2015; Wyller, 2019).…”