PETROLEUM GEOLOGY OF THE UNITED ARAB EMIRATES

The Permain to Holocene sediments of the United Arab Emirates consist mainly of epeiric shelf carbonates, associated with minor clastics and evaporites, reflecting major cycles of transgression and regression. These were deposited on the eastern margin of the Arabian Sheild, which lay along the southern margin of the Tethys Ocean during the Mesozoic‐Cenozoic eras. Sedimentation patterns were controlled by prominent regional structural features, epeirogenic movements and/or sea‐level fluctuations.The tectonic history of the UAE in the Mesozoic‐Cenozoic is connected with the opening (Triassic) and closure (Upper Cretaceous‐Paleogene) of the southern Neo‐Tethys Ocean.The distinctive structural style, together with the tripartite development of source‐reservoir‐seal, has produced in the UAE one of the world's richest Jurassic ‐ Cretaceous oil habitats. Significant oil discoveries have also been made in the Permian; Middle and Upper Jurassic; Lower‐Middle‐Upper Cretaceous and Oligo‐Miocene carbonates.Two main source rocks have been identified. One is the Upper Jurassic Diyab/Dukhan Formation, which supplies the most prolific reservoirs in the Upper Jurassic (Arab Formation) and Lower Cretaceous (Thamama Group). The other is the Middle Cretaceous Shilaif/Khatiyah Formation, which feeds both Mishrif and Simsima reservoirs. Other minor potential source rocks have also been identified in the study area.There are two principal sealing formations ‐ the Hith Anhydrite and the Nahr Umr shale; these are the main seals for the oil and gas accumulations in the underlying Arab Formation and Thamama Group, respectively. Secondary seals and barriers also exist in the stratigraphic sequence.