In fractured buried reservoirs, the fracturing network has a significant impact on fluid circulation and productivity. In this work, we present the results of the analysis of outcrop fracture networks in the Upper Middle Eocene limestone hydrocarbons reservoir, located in Central Tunisia. The study considered outcrops in two different structures and geometries in Jebel Cherahil, which is located in the North-South Chain of Central Tunisia. The aim of this study is to characterize the fracturing of the Cherahil Formation using statistical method from outcrops. This field data constitutes the important support from which statistical processing are made. Indeed, the statistical analysis of the length, spacing and aperture parameters shows a power law fit of the curves. Thereby, it indicates a degree of self-similarity in the organization of the fracture network which highlight the fractal nature of the fracture network. In fact, the fracture network is organized along four main directions: ESE-WNW, E-W, SE-NW and ENE-WSW on the western flank, and in three major directions: ESE-WNW, ENE-WSW and SE-NW in the vicinity of the major N160 fault.


Quantitative characterization of fracturing associated with different geological formations is an essential means of gaining a better understanding of fractured aquifers in the basement, for example. The determination of the geometrical parameters of the fracturing (orientation, length, spacing, opening, etc.) allows to better understand the organization of the fracture networks (Guerriero et al., 2010; Wilson et al., 2011; Hooker et al., 2013, 2014, Laubach et al., 2019; Guiffrida et al., 2019; Guiffrida et al., 2020; Pontes et al., 2021). These parameters play a significant role in the organization of the fracture network and its transport properties (Razack, 1982; La Pointe and Hudson, 1985; Lasm, 2000, Gillespie et al. 2011, Coli and Pinzani, 2014). We should also mention that statistical analysis methods remain inevitable in the study of these parameters by simplifying the description of the main geometric parameters of fracturing (La pointe and Hudson, 1985; Lasm, 2000). In Tunisia, the Cherahil reservoir represents a petroleum interest since it is produced in many wells (Sidi El Itayem and Kerkanah). The Cherahil B formation is a thick (200 -350 m) multilayer potential reservoir/seal which defined by Bramaud (1971) and Dufaure and Comte (1973) from Jebel Cherahil in west of Nasrallah.

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