Salt Plugs and Diapirism and Its Tectonic Implications to the Oil Fields in the United Arab Emirates

A. S. Alsharhan

In the United Arab Emirates (UAE) the distinctive structural style, together with the tripartite development of source-reservoir-seal has produced in the country one of the world's richest Jurassic-Cretaceous oil habitats. Oil and gas mainly occur in structural traps associated subtle stratigraphic and diagenetic traps.

Salt domes and plugs are distributed irregularly throughout the southern Arabian Gulf and much of the existing structural relief in U.A.E. oil fields are directly related to salt diaprism. There are large number of emergent diapiric salt plugs of a few km across reaching the surface after penetrating through the Mesozoic and Tertiary successions. They commonly form salt-cored islands framed by sedimentary layers in the offshore and low relief mountains in the onshore region.

Diapiric structures of the large, shallow dome-type are common, resulting from salt pillows at depth, as at Zakum, Umm Shaif and Fateh; these fields were formed by the diapiric movement of Infracambrian salt which began early in the Cretaceous. Periodic mobilization of salt has created unconformities across the top of some structures. There is however, fairly conclusive evidence that nearly all the producing fields in the southern Arabian Gulf are influenced to different degrees by tectonics of the mobile Infracambrian salt. The influence of salt is deep-seated, because no structural complexity or serious stratigraphical anomalies have been found. The characteristic circular and subcircular domal geometry of the structures implies the presence of a localized epicentre of upwarping.

AAPG Search and Discovery Article #91020©1995 AAPG Annual Convention, Houston, Texas, May 5-8, 1995