--> Abstract: Stratigraphic Framework of the Natih Formation in Oman, by Henk J. Droste; #90077 (2008)

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Stratigraphic Framework of the Natih Formation in Oman

Henk J. Droste
Shell, Oman
[email protected]

Carbonates of the Albian to Turonian Natih Formation are important hydrocarbon reservoirs in Oman. A regional sequence stratigraphic study integrating seismic and well data of interior Oman led to a better understanding of the reservoir and seal distribution as well as the stratigraphic trapping potential. Deposition took place on an epeiric shelf with carbonate platform development at the ocean-ward margin, located in northern and eastern Oman, whereas clastics predominated along the exposed Arabian Shield in the southwest. Lateral shifts in clastic and carbonate facies belts, driven by changes in relative sea level and climate, resulted in a hierarchical stacking of depositional cycles of several 10s up to some 150 m thick. Two major flooding events, with widespread deposition of pelagic carbonates, occurred in the Late Albian and Late Cenomanian. Both are associated with the creation of significant depositional topography (up to 100 m) as a result of aggradational carbonate growth along the margin. This was followed by a strong platform progradation over more than 100 km towards the interior of the epeiric shelf. Variations in the type and amount of sediment input, both in time and space, caused major variations in reservoir geometry and properties within these prograding complexes. A major fall in sea level in the Mid-Cenomanian led to exposure and channel incision of the platforms and a major influx of clastics. Fine-grained clastics also covered most of the Lower Cenomanian platform during the initial stage of the following relative sea-level rise. Quartz sands trapped between the exposed carbonate platforms may provide opportunities for stratigraphic traps.

 

AAPG Search and Discovery Article #90077©2008 GEO 2008 Middle East Conference and Exhibition, Manama, Bahrain