Print this pageAAPG GEO 2010 Middle East
Geoscience Conference & Exhibition
Innovative Geoscience Solutions – Meeting Hydrocarbon Demand in Changing Times
March 7-10, 2010 – Manama, Bahrain
Tectonic Effects from the Hydrodynamics of the Arab-D Reservoir in Eastern Arabia
(1) Exploration, Saudi Aramco, Dhahran, Saudi Arabia.
(2) Geology Department, Ain Shams University, Cairo, Egypt.
The Arab-D reservoir is exposed in central Arabia and dips eastward into the Arabian Gulf. Late Jurassic extensional deformation, associated with opening of the NeoTethys and Late Cretaceous - Recent compressional deformation, related to convergence between the Arabian and Eurasian Plates, affected the hydrodynamics of the Arab-D reservoir. The Late Jurassic extensional phase created the East Arabian basin which controlled the deposition of the Arab-D carbonates and anhydrites. The anhydrite at the top of the Arab-D is a seal for the underlying carbonates forming the regional flow unit of the Arab-D reservoir. The deeper parts of the East Arabian basin continued to exist in Eastern Saudi Arabia since it was created. This caused the groundwater to flow by gravity from central to Eastern Arabia. The Late Cretaceous - Recent compressional deformation led to uplifting of the Zagros and Oman mountains, eastward tilting of the Arabian Plate, reactivation of pre-existing north-south faults, and formation of the Central Arabian graben system. The uplifting of Zagros and Oman mountains and eastward tilting of the Arabian Plate caused the groundwater to flow from structurally high areas in central Arabia, the Zagros and Oman mountains to low areas in Eastern Arabia. The reactivation of pre-existing north-south faults created faults in the Arab-D, which include fault breccia or calcite-filled zones acting as barriers to fluid flow surrounded by damage zones that act as fluid flow conduits. This fault zone architecture caused deflections in groundwater flow and connectivity between reservoirs at regional and local scales. The Central Arabian graben system formed an east-west corridor of intensively fractured rocks which acts as a fast track for groundwater flow from the outcrops in Central Arabia to deep areas in the east.