Tectonic Controls on Development of the Zagros: Implications for Hydrocarbon Systems

The main tectonic controls on the development of structural traps and fractured reservoirs include: the oblique (transpressional) collision between Arabia and Eurasia; the mechanical stratigraphy of the Palaeozoic cover sequence; and the effects of structural inheritance. Partitioning of transpressional deformation has caused localisation of strike-slip (or oblique-slip) into complex fault zones oriented oblique to the Zagros trend. The alternating sequence of mechanically strong carbonates and weak evaporites and shales has a major effect on trap geometry and complexity. Structural inheritance is interpreted to have played a critical role during the right-lateral reactivation of basement faults to form many of the giant fields in southern Iraq.