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Sedimentary Facies and Fracturing in the Upper Cretaceous Apulian Platform Carbonates of the Murge Foreland and Maiella Mountain, Southern Italy: Excellent Analogues to Better Understand Subsurface Reservoir Characteristics


Di Cuia, Raffaele1, Claude Gout2, Massimo Sarti3, Loic Balzagette4 (1) G.E.Plan Consulting, Italy, Ferrara, Italy (2) Total E&P Syrie, Damascus, Syria (3) Polytech. University of Marche, Ancona, Italy (4) Université Montpellier II, Montpellier, France


The Upper Cretaceous Apulian Carbonates of the Murge foreland and of the Maiella Mountain represent good reservoir analogues for some of the Italian oil fields deeply buried underneath the Southern Apennines Thrust Belt.

The selected outcrop analogues present same age interval, similar depositional system, and were deposited in the same paleo-climatic conditions than the subsurface reservoirs. The architecture of the platform is provided by the stacking of multiple-order stratigraphic cycles of tidal origin. At the lithozone scale, the variability in thickness and facies is in the range of tens of kilometres. At the facies scale, variability is much more pronounced, with variations in the range 100-300 meters. Individual depositional elements may significantly change their geometric and facial characters in 10-100 meters.

Fracturing is less pervasive in the foreland Murge outcrops than in the Maiella mountain. Fine-grained sedimentary facies have by higher fracture densities, fracture sets are often sub-parallel and bed-confined and represent bed-parallel conduits. Laterally discontinuous coarse rudist associations and coarse-grained sedimentary facies are characterised by scarce fracturing. All sedimentary facies are connected by fractures that cross and connect several intervals. In this way, a dense network of fractures and matrix porosity can be con­nected.

The relationships between facies and fracturing show similar characteristics in the two outcrop analogues even if they lie in two different tectonic settings (foreland and thrust belt). This observation is fundamental for extrapolation to subsurface reservoirs: it implies that fracture distribution in carbonate reservoirs like the Apulian platform is relatively independ­ent of the tectonic regime but is strongly influenced by facies.