Parameters controlling the quality of the Hamra Quartzite reservoir, southern Hassi Messaoud, Algeria: insights from a petrographic, geochemical, and provenance study

摘要

Petrographic and geochemical analysis of theHamra Quartzite reservoir in the southern periphery of the Hassi Messaoud field has been undertaken. The aim is to identify the quality of these sandstones as well as their tectonic setting and possible provenance. Petrographic analysis reveals that the studied reservoir is constituted of fine- to coarse-grained sandstones in which quartz forms the principal framework mineral. The main cement phases identified in this reservoir are quartz, illite, and carbonate, precipitated in that order. The principal diagenetic factors controlling the reservoir quality are quartz overgrowths, formation of authigenic clays, and the precipitation of carbonate cement. The Hamra Quartzite reservoir is considered mature from a compositional point of view as it consists predominantly of quartz arenites. Geochemically, these sandstones have a high SiO_2 content (93.28-98.79 wt%). The Hamra Quartzite deposits appear to be derived from deeply weathered (under warm-humid climate conditions) granitic- gneissic terrains or recycled sedimentary source areas. A passive margin origin is the most likely tectonic setting for the depositional environment of these arenites. The reservoirqualityis stronglyinfluencedbythe relationshipbetween the clay content andmineralogy. The combined effect of quartz overgrowth and the plugging of pores by illite have reduced both porosityandpermeability.Asa result, economically viable oil production in this area will depend most strongly on the combination ofmatrix and fracture porosity.