oa Prediction of Reservoir Heterogeneity and Quality: Examples and Lessons from Outcrop Analogs from Wajid Sandstone, Saudi Arabia

This study tends to characterize the reservoir rock heterogeneity and quality using sedimentological,<br>statistical and geostatistical approaches. Paleozoic fluvial and shallow marine outcrop reservoir analogs<br>from the Wajid Sandstone in south west Saudi Arabia are the target for this study. The impact of<br>depositional and post depositional parameters on porosity and permeability distribution were<br>investigated on macro- to micro-scale. The study revealed wide range of facies, environments, textural<br>and compositional variations at outcrop scale. The porosity and permeability distribution show<br>variability and complex patterns most probably reflecting different scale of depositional and diagenetic<br>influences. The complex relations among parameters may be attributed to variable interrelationships.<br>At the macro to meso-scale these include the meter-scale statigraphic hierarchy, depositional cyclcity<br>and lateral and vertical facies changes. While at micro-scale petrographic features such as grain size,<br>sorting, matrix and cement content and type all seem to be influential. The geostatistical porosity and<br>permeability models show some agreement and differences which can also be attributed to the<br>aforementioned controlling factors.