Carbonate Deposition and Diagenesis of the Thamama Group

The Lower Cretaceous Thamama Group represents an extensive, carbonate ramp system that hosts many complex, stacked reservoirs both onshore and offshore throughout the Arabian Gulf. Various techniques have been applied using bounding sequence stratigraphic surfaces to correlate the Thamama throughout the whole of the southeastern Arabian Gulf oil province, but many have proved inadequate in the prediction of reservoir flow behavior and oil recovery. As in many carbonate fields, the main challenges in building a reservoir model are establishing valid criteria for field-wide correlation, an adequate understanding of lateral heterogeneity, and the relative roles of depositional and diagenetic processes in determining reservoir quality.

In collaboration with Dr. Tony Dickson (University of Cambridge), we are re-appraising the sequence stratigraphy and diagenesis of a major offshore field in U.A.E. using both wireline log and core data. We have established a revised paragenetic sequence based on separated component stable isotopic analysis, and are evaluating the preferential role of diagenesis in the evolution of porosity and permeability.

Peter Cox (Ph.D) student is extending this work in the Lekhwair Formation to onshore U.A.E. and outcrop Oman.