Structural Style and Growth History in Saudi Arabia
Hong-Bin Xiao1, Abdulla A. Bokhari1, Randall G. Demaree2
(1) Saudi Aramco, Dhahran, Saudi Arabia (2) Saudi Aramco, Saudi Arabia
Most of the hydrocarbon fields in Saudi Arabia are basement-cored uplifts. These structures are compressional, typically low relief, bounded by steep frontal fault, and backthrust in some cases. The most common trap type is four-way closure, although subcrop-trap, fault-trap, and stratigraphic trap are becoming increasingly important.
We quantitatively assessed growth history of each structure by adapting the concept of growth index, which is a numerical ratio of strata thickness in trough over crest. Every structure was given a set of four numbers (starting from 1 indicating no growth), each indicating the severity of one of four orogenic deformation: Carboniferous (Hercynian Orogeny), Early Triassic (Zagros Rifting), Late Cretaceous (First Alpine Orogeny), and Tertiary (Second Alpine Orogeny) time, respectively. Maps of structural growth indicate that most of the structures have persisted from Carboniferous to Holocene. The maximum principal horizontal stress in Late Cretaceous seems to be oriented NW-SE direction and was responsible for maximum growth of some of NE-SW oriented structures such as Abqaiq, Harmaliyah, Shaybah, and Tukhman. The Central Arabian Arch has long been a strain compartment boundary where the strongest deformation occurs and persists, and where most E-vergent structures are located to the north and most W-vergent structures are to the south.