Etude sédimentologique du Trias argilo-gréseux du champ Sif Fatima « bassin de Berkine » : Analyse pétrographique, minéralogique et diagénétique

Abstract

The present work consists of the sedimentological, petrographic and diagenetic phenomena of the sandstone clay Triassic of three wells (well 1, wells 2 and 3) in the region of Sif Fatima which is part of the Berkine basin. The descriptive analysis of 405.00m of cores makes it possible to identify two units: The lower unit corresponding to TAGI, the upper unit is the carbonated trias. The diagenetic transformations of TAGI sandstones are manifested by the phenomena of dissolution, silica precipitation, the transformation of illitic clay into kaolinitic clay, but the most important is the dominance of syntactic quartz. The TAGI sandstones are generally distinguished by an estimated value of porosity which are often rather low because of clay enrichment, this richness is represented by different granulometry, partly explains the reduction of intergranular porosity but also by the establishment of a diagenetic cementation sometimes intensive and multiphasic (dolomite, anhydrite, silicification).