Peculiar Structural Geometry of Abu Dhabi Fields

Abstract A reasonable model for folding evolution in Abu Dhabi is presented answering the questions of the many interpretations for the folding patterns. If these folds related to the compressional forces, then why they did not represent series of anticlines and synclines? Why they dissected? Why showing different amplitudes from the deflection to the hinges zones? And finally, why the main geometry is open folding style and did not showing step dipping limbs towards the direction of the compression more than the other limb? The giant Fields of Abu Dhabi, UAE possess different geometries and structural patterns. These patterns can be subdivided into two main categories, salt related, and tectonic related. The tectonic related patterns are mainly folding related faults. Most of the fields are double plunging anticlines for the fault related tectonic and four-way domal anticlines in salt related, with few out of both possess unusual structural geometry. This paper addresses these structural patterns in order to shed lights on the trapping mechanism, in a multi-disciplinary approach of well data, seismic, potential data and outcrop analogues. The initial fold axes were determined; the axial plane and direction of heterogeneous shear displacement responding to the first folding and refolding phases were addressed. Unique shaped folds can be grouped in 6 major patterns that can be differentiated into: The first pattern evolved as dip-closed triple plunging anticline with a northeastern plunge and the southern plunge is bifurcated into two trends; SE and SW. Refold structures showing physical orientation of the first and the second fold generation in a closed pattern. Cone shaped pattern, which possess extended northern hinge zone, while the southern closure is tapering in nature. Snail and Tongue shaped patterns, which are deep rooted by salt diapir. Zigzag shaped pattern, which is mainly evolved in response of connecting pop-up structures related to wrench faults. Chevron High amplitude closed anticline, which is the only and unique pattern, as all others are open folds. A close relationship of the kinematics and timing between high-angle strike-slip faulting and upright folding is established for the Cretaceous systems. Folding accompanied tectonic denudation developing elongated plunging anticlines with fold axes both parallel and perpendicular to the direction of transpression. The strike-slip systems trending NW-SE of transpressional forces led to evolution of most of the anticlinal fields of tectonic nature in Abu Dhabi. The structural patterns of the fields and their kinematic evolution leads to understand their genetic and dynamic evolution and hence understanding the trapping mechanisms effectively.