Diagenetic controls on reservoir properties of carbonate successions within the Albian–Turonian of the Arabian Plate

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, deeppenetrating 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 CretaceousTertiary. 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.

Controls on depositional facies in Upper Cretaceous carbonate reservoirs in the Zagros area and the Persian Gulf, Iran

“…A regional uplift following the ophiolite obduction caused a deep erosion and/or non-deposition of the carbonate sequences (i.e., Sarvak and Ilam formations and their stratigraphic equivalents) in various parts of the Middle East (Fig. 3), particularly where the salt diapirism and basement fault reactivation have resulted in the formation of structural highs (Stoneley 1981;Jahani et al 2007;Hollis 2011).…”

Palaeo‐exposure Surfaces in Cenomanian – Santonian Carbonate Reservoirs in the Dezful Embayment, Sw Iran

“…The Cenomanian -Santonian sedimentary succession on the Arabian Plate, including the Dezful Embayment of SW Iran and the Mesopotamian Basin of Iraq (Fig. 2), comprises shallow-marine carbonates deposited on ramp-like platforms bordering intrashelf basins which developed towards the NE plate margin (Setudehnia, 1978;Alsharhan et al, 1986Alsharhan et al, , 1988Aqrawi et al, 1998;Hollis, 2011;Lapponi et al, 2011). Major volumes of hydrocarbons are hosted within these carbonates, for example in Oman (Natih Formation), the United Arab Emirates (Mishrif Formation), offshore Qatar (Khatiyah and Mishrif Formations), Kuwait (Rumaila and Mishrif Formations), Iraq (Rumaila and Mishrif Formations), Turkey (Derdere Formation) and Iran (Sarvak and Ilam Formations).…”

“…Subaerial exposure of mid-Cretaceous carbonates under a warm and humid climate on the Arabian Plate had different effects depending on several factors including tectonic regime and duration of exposure (Ehrenberg et al, 2008;Weidlich, 2010;Razin et al, 2010;van Buchem et al, 2011;Hollis, 2011). Shortterm emergence (generally less than one million years) caused reservoir quality improvement in underlying carbonate rocks by developing karst and microkarst networks.…”

“…Fluid migration paths are also controlled substantially by these unconformable boundaries (Jolley et al, 2010). Therefore, disconformity surfaces appear to have important controls on the reservoir quality of carbonate rocks (Immenhauser et al, 2000;Hollis, 2011).…”

Fundamental controls on fluid flow in carbonates: current workflows to emerging technologies

“…Related and complementary perspectives can be found in Geological Society Special Publications and related journals (e.g. van Buchem et al 2010;Hollis 2011;Garland et al 2012;Agar & Hampson 2014).…”