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Relationship between Carbonate Platforms and Reservoir Characteristics of Mesozoic and Cenozoic Systems of the Middle East to Eustasy and Paleoclimatic Settings

Alsharhan, Abdulrahman S.*1; Kendall, Christopher G.2
(1) Middle East Geological Establishment, Al-Ain, United Arab Emirates.
(2) University of South Carolina, Columbia, SC.

Recent studies of subsurface data from Middle East carbonate reservoirs have established the strong relationship of the frequency and amplitude of relative sea-level change, paleoclimate, depositional setting to the geometries of the facies, their petro -fabrics and the diagenetic pathways the carbonate reservoirs experienced.

Gentle tectonic subsidence punctuated by variations in eustasy partly controlled the accommodation of these carbonate platforms, evaporites and their associated minor clastics and so their geometric shapes. The facies geometry and later diagenesis was further modulated by varying humid to arid tropic conditions that controlled the depositional settings of the producing carbonate formations, particularly during major and local subaerial exposure events. Many of the local reservoirs were developed under arid climatic conditions associated with platform-wide evaporite events. Superimposed on each reservoir are distinct diagenetic patterns and reservoir characteristics induced by carbonate cementation, dolomitization, leaching, karstification, fracturing, compaction and/or stylolitization. Halokinetic and deep seated faults or basement and platform-margin tectonism played fundamental roles in determining the carbonate platform types, sedimentation pattern, and depositional systems.

Three well-documented examples are presented to record and explain the above paradigms:

1-Humid carbonate related to major subaerial unconformities characterized by the Shuaiba, Mishrif, Simsima, Sarvak, Natih formations and Kirkuk Group.

2-Humid carbonate related to local subaerial exposure in upward shallowing cycles of Araej, Dharuma, Habshan, Minagish, Yamama, and Lekhwair-Kharaib formations.

3- Arid carbonate related to platform-wide evaporitic events are characterized by the Khuff, Dalan, Arab, Asmari, Euphrates-Jeribe, Triassic of Northern Arabian plate and Lower Fars formations.  

 

AAPG Search and Discovery Article #90142 © 2012 AAPG Annual Convention and Exhibition, April 22-25, 2012, Long Beach, California