Integration of Sedimentology, Sequence Stratigraphy, and Seismic Stratigraphy of the Lower Cretaceous Shu’aiba Formation in an Oil Field of Northwest Abu Dhabi, United Arab Emirates

Ahmed Ghani¹*, David G. Barwick¹, Christian J. Strohmenger¹, Suhaila H.A. Al-Mazrooei¹**, Naema O. Al-Zaabi¹, and Thomas Steuber^2
1ADCO
²The Petroleum Institute, UAE
*[email protected]
**[email protected]

The Lower Cretaceous (Aptian) Shu’aiba Formation is an important carbonate reservoir of the subsurface of Abu Dhabi. At an oil field located in northwest Abu Dhabi, the reservoir is comprised of interior platform, platform margin, clinoform belt (prograding wedges) and intra-shelf basin deposits. Sedimentologic and petrographic core description identified 12 lithofacies types, ranging from shallow-marine, rudist-rudstone to deep-marine, planktonic foraminifera wackestone and shale. Caprinids (Offneria sp.) dominate the Shu’aiba platform margin and the proximal clinoform belt. Algal-stromatoporoid facies and caprotinid debris are indicative of the distal clinoform belt. Planktonic foraminifera wackestone and shales dominate the intra-shelf basin deposits (Bab Member). The Shu’aiba deposits at an oil field located in northwest Abu Dhabi fit well into the sequence stratigraphic framework established for a giant oil field of central Abu Dhabi. Shu’aiba transgressive and early highstand sequence sets are built by the Ap2 and Ap3 sequences, Shu’aiba late highstand sequence set comprises the Ap4 and Ap5 sequences, and the Bab lowstand sequence set is represented by the Ap6 sequence. However, the platform margin appears to be steeper in northwest Abu Dhabi, as the area of the Upper Aptian (Ap4 and Ap5 sequences) distal clinoform belt is narrower than the one encountered at central Abu Dhabi. Three-dimensional seismic analyses allow mapping of the platform to basin geometries. The areal extent of the interior platform, the platform margin, the clinoform belt, and the Bab Basin can be outlined by seismic cross-sections and seismic amplitude maps. All available data were successfully incorporated in a new 3-D static model, addressing uncertainties in terms of structure, stratigraphy, and reservoir quality.

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