Abstract

ABSTRACT

The carbonate-dominated Albian to Turonian succession is one of the key petroleum systems of the Arabian Plate. It is dominated by shallow water platform carbonates that were deposited in a shallow epeiric sea on the margins of Neotethys. In general, the reservoirs in this succession have high porosities but exhibit heterogeneous permeabilities. This study reviews published data for the region and attempts to unravel the key diagenetic controls on the porosity and permeability of the reservoirs. The results demonstrate that a spectrum of diagenetic processes created highly heterogeneous multimodal pore networks. Intense boring and micritization of skeletal allochems, differential cementation of a pervasive burrow network and preferential dissolution of aragonitic skeletal allochems are ubiquitous. Locally, particularly on the northern and eastern Arabian Plate, deep-penetrating epikarst can be tied to a differential response to global sea level fluctuation and local tectonism. The development of a peripheral bulge in late Cenomanian–Turonian times, halokinesis, localized influx of channelized clastic material and sub-regional climatic variability contributed to a heterogeneous pattern of meteoric diagenesis across the Arabian Plate. The succession was then buried to up to 10 km during the Late Cretaceous–Tertiary. Where deep-penetrating fault systems were reactivated by Alpine tectonism, flushing by hydrothermal brines resulted in highly localized patterns of hydrothermal dolomitization and leaching, associated with hydrocarbon emplacement.

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