Online Journal for E&P Geoscientists

Abdullatif, Osman M.^*1; Siddiqi, Saad ²; Mahgoub, Mohammed ³; Abdulkadir, Ibrahim ⁴
(1) Earth Sciences, KFUPM, Dhahran, Saudi Arabia. (2) CoreLab, Dubai, United Arab Emirates. (3) Schlumberger, Doha, Qatar. (4) ETS, Dammam, Saudi Arabia.

The Paleozoic Wajid sandstone Formation occupies most part of south western Saudi Arabia and in Rub al Khali basin. The Wajid Formation consists of four member, namely Dibsiyah, Sanamah, Khussyan and Juwayl members which deposited within fluvial, glacial, peri-glacial and shallow marine environments. The Wajid represents important aquifer and potential reservoir for both conventional and unconventional hydrocarbon resources in several basinal areas. Understanding and predicting reservoir properties and quality of Wajid members in the subsurface has been an exploration challenge. This is partly due to scarcity of subsurface data and mainly because of the complexity of the paleogeographic setting, environments and facies through space and time. This study utilized outcrop data from rocks stratigraphically-equivalent to Wajid members in south western Saudi Arabia. The study utilized sedimentary facies, thin section petrography and geochemistry of major, trace and rare earth elements to investigate the sandstone composition, provenance, tectonic setting and weathering history. The results indicate rather some variability, similarity and differences among Wajid members in terms of sandstone composition, grain framework, nature and types detrital sources. The Wajid sediment evolutionary history might be attributed climatic as well as depositional and post-depositional controls on Wajid members. Modeling facies properties from Wajid outcrop and their integration with subsurface data may to identify and reveal some aspects of exploration complexity and challenges and help reservoir quality prediction.