Fracture Properties in Naturally Fractured Carbonate Reservoir (Gourigueur Eocene Syncline, North-Eastern Algeria)

The Gourigueur fractured Eocene carbonate rocks constitute one of the groundwater aquifers in the Tebessa region (north-eastern Algeria). The present work aims to characterize the fractures of this aquifer from a multiscale analysis. The Gourigueur syncline oriented NE-SW, extends over twenty kilometres from SW to NE and about five kilometres from NW to SE. The fracture orientations measured from the outcrops have allowed us to identify two of the most dominant fracture sets (d1 and d2) which are respectively a longitudinal set, which is normal to the fold axis, and a transverse set, much less abundant, which is oblique to the trend of the structure. Their mean orientations are respectively NNE-SSW and NNW-SSE (Hireche in Analyse multi-scalaire de la fracturation du reservoir carbonate eocene du synclinal de Gourigueur (Region de Tebessa, Algerie Nord orientale), [1]). The microfaciologic analysis allowed us to show that the porosity of these Eocene fractured carbonate rocks is mainly controlled by the fracture porosity; the matrix porosity is very low or even null for some facies (Hireche in Analyse multi-scalaire de la fracturation du reservoir carbonate eocene du synclinal de Gourigueur (Region de Tebessa, Algerie Nord orientale), [1]).