Türkiye Jeoloji Bülteni

Stratigraphic Evolution of the Midyan Basin and its Hydrocarbon Potential (NW Saudi Arabia)

Abstract: The hydrocarbon-producing Midyan Basin  is located in northwestern Saudi Arabia and is surroundedby the Proterozoic igneous basement of the Arabian Shield. It includes thick hydrocarbon-producing sedimentarysequences deposited in half-grabens that formed during rifting of the Red Sea and the gulfs of Suez and Aqabain the Early Miocene  (23.3 Ma). The early syn-rift succession consists of arid alluvial fan sediments and playa evaporates followed by shallow marine carbonates. The late syn-rift sequences consist of  progradational deep seaturbidites and Alpine-type glacial deposits indicating strong vertical uplift during the climax of the rifting (19 Ma). The post-rift succession overlies the late syn-rift successions and consist of shallow marine marls and evaporites. The aim of this study is to examine the hydrocarbon potential of the turbidite sandstones and the formation of varioustypes of glacial deposits in the Burqan Formation. This study also encompasses the importance of various geologicprocesses in order to understand their significant influence on the geometry continuity and reservoir quality of oiland gas producing genetically different sandstones in the subsurface of the Burqan Formation in the Midyan Basin. The Alpine-type glacial deposits provide an excellent opportunity to study the presence of continuous vertical and lateral facies variations between true glacial glacio-fluvial and glacio-marine deposits in the direction of sediment transportation.  Unsorted moraines deposited in the deep and U-shaped glacial valleys occupy the northwestern partof the basin. They pass gardually in glacio-fluvial sandstones. that contain large polished and striated boulders.  Inthe southeastern part of the deep basin , the glacio-marine deposits are associated with deep sea turbidites and pelagicshales. Many stratigraphic and sedimentologic sections were measured from well-exposed outcrops in every partof the basin to establish various depositional environments. A large number of sandstone samples was collected toexamine their reservoir quality.