Sedimentology and Sequence Stratigraphy of the Mishrif Formation and it's Impact on Reservoir Heterogeniety, Rumaila Field, Southern Iraq

Abstract

The Upper Cretaceous Mishrif Formation of Southern Iraq deposited as part of a large carbonate platform system spanning across the Arabian Plate from Iraq to Oman. The carbonates are the host of some of the most prolific hydrocarbon accumulations and form one of the major reservoir units of the Rumaila Field. The Mishrif Formation is part of the second-order systems tract spanning from the upper-most Albian to the Turonian. The Ahmadi Formation is part of the Transgressive Systems Tract (TST), and the Rumaila and the Mishrif Formations are part of the Highstand Systems Tract (HST). The Mishrif is bound at the top by an Arabian plate-wide unconformity. The Mishrif Formation was further divided into five 3rd-order sequences. The lower three of these sequences comprise the Mishrif B (mB) while the upper two sequences make up the Mishrif A (mA). Extensive core studies helped to understand the depositional environment and the impact of the sequences on reservoir quality of the Mishrif reservoir.