Structural Control on Permo-Triassic Deposition in the Central Arabian Plate: A Multi-scale Approach

摘要

A multi-scale analysis integrating structural concepts, local seismic data and well correlations across the Central Arabian Plate demonstrates that the thickness and facies distributions of one of the most important hydrocarbon reservoirs in the Middle East, the Khuff carbonate, are strongly controlled not only by the structural relief at time of deposition but also by the reactivation of the basement structural fabric related to Permo-Triassic tectonic events. Stratigraphic and sedimentological data indicate that on a regional scale, the Khuff carbonate shows a wide variety of depositional environments (with facies ranging from coastal plain anhydritic claystone, tidal flat/low-to-high energy lagoonal deposits to open-marine dolostones alternating with grainy limestones and high-energy shoal-dominated dolostone/thick grainy limestones) and thicknesses (from near zero at the pinch-out of siliciclastic facies in central Saudi Arabia, to more than 400 m (1300 ft) in the Ghawar field in northern Saudi Arabia, expanding to 800 m (2600 ft) in the North field, Qatar and to nearly 1000 m (3300 ft) in the eastern United Arab Emirates). Pre-Khuff basement-related anisotropies on the Arabian Peninsula are interpreted to have formed as early as Late Neo-Proterozoic to Ediacarian time and to follow three main trends: (i) N-S (Nabitah), (ii) NW-SE to WNW-ESE (Najd), (iii) NNW-SSE to NW-SE (Mesopotamian).