Reservoir heterogeneity and quality of the lower to Middle Paleozoic formations; outcrop analogue, Saudi Arabia

From Early Cambrian to Late Ordovician, Saudi Arabia characterized by the deposition of Siq, Quweira, Saq, Qasim and Sarah Formations respectively. The depositional environments of these formations range from alluvial to fluvial system to marine setting and end up with a glaciation period led to the deposition of Sarah Formation. The aim of this study is to carry out a comparative outcrop analogue study among four Paleozoic Formations in term of their stratigraphic and sedimentologic heterogeneity and reservoir quality and architecture. Field and laboratory analyses were conducted including lithofacies analysis, sampling, XRD, XRF, SEM and petrophysical measurements. The results revealed variation in terms of occurrence, field relationships, lithofacies, depositional environments and stratigraphic architecture. On micro-scale sandstones were affected by intrabsinal depositional controls and the influence of the diagenesis, compaction and cementation by quartz overgrowth, the clay minerals kaolinite and the iron oxides all together play a role in affecting the reservoir quality.