Grain-Size Analysis of Middle Cretaceous Sandstone Reservoirs, the Wasia Formation, Riyadh Province, Saudi Arabia

Grain-size analysis is a significant descriptive method to determine and evaluate depositional environments hydrodynamic conditions in addition classifying sedimentary rocks. In this study, grain-size was conducted using dry-sieving procedures on fourteen representative sandstone samples from the Wasia Formation, thick water aquifer hydrocarbon reservoir. Hydrodynamic were determined bivariate plots, linear discriminate function (LDF), log probability, Passega diagram. The results reveal that lower outcrop section consists of coarse- medium-grained with majority being poorly sorted, while upper made up medium- medium-well-sorted fine-grained units. sediments have unimodal distribution 2∅ (all section) 3∅ (most section), two beds bimodal 2 3∅. has wide range skewness mainly mesokurtic curves, near-symmetrical coarse-skewed but mostly leptokurtic. Additionally, probability plots diagram show indicative transported via one saltation levels, fine-grains suspension. LDF are predominantly aeolian, marine, fluvial environments.