Barremian/Aptian Carbonate Systems of the Eastern Arabian Plate – A Global Sequence Stratigraphic Reference Model

Frans S. Van Buchem
Maersk Oil Qatar AS, Doha, Qatar

Geological studies covering a wide range of disciplines and analytical tools have been carried out over the last 40 years on the Barremian-Aptian deposits in the Middle East which contain some of the most prolific carbonate reservoirs in the world. With reservoirs becoming more mature, it has become more important to further improve the understanding of their detailed architecture. One way to improve that knowledge is to integrate the existing data in a comprehensive, time-controlled stratigraphic framework. This framework will allow establishing basin-wide correlations, and thus the comparison between reservoirs of fields in different phases of development.

The time framework which is now being elaborated for this interval combines biostratigraphic and chemostratigraphic dating techniques, together with geometrical information from high-resolution 3-D seismic surveys and seismic-scale outcrops. New data on ammonites and orbitolinids as well as on carbon- and strontium-isotopes from Iran, Oman, Saudi Arabia, the United Arab Emirates and Yemen, have greatly improved the time control and provide regionally consistent dating for the depositional sequences in the Barremian and Aptian.

Three second-order sequences have been defined, each composed of third-order sequences. A robust facies pattern has been identified within this sequence stratigraphic framework, providing a predictive tool for the characterization of this reservoir-seal-source system. Basin-wide variations in accommodation and climatically controlled variables, such as wind and current directions, have locally shaped the specific expression of the sedimentary facies and the stratigraphic architecture.

The quality of the time control and the density of the data points make this Barremian-Aptian dataset one of the most detailed and best constrained worldwide. The sequence stratigraphic model and the resulting (relative) sea level curve can consequently be considered as good candidates for a global reference model.

AAPG Search and Discovery Article #90101 © 2010 AAPG Foundation Distinguished Lecturer Series 2009-2010