Basin Analysis of the Late Cretaceous Sediments in United Arab Emirates

The Late Cretaceous Simsima Formation has been proved to be one of the most prolific reservoirs in the Arabian Basin, but still needs more investigations to be ultimately exploited.This promising formation has been subjected to a comprehensive study by various geologic disciplines to build up an adequate basin model for such formation. The study revealed that the Late Cretaceous Simsima Formation could be classified into two facies. These are Planktonic Foraminiferal Biomicrite (open marine source rock facies outcropped at Jabal Qarn El-Barr); and Rudistids Algal Foraminiferal Biomicrite (shallow marine reservoir rock facies exposed at Jabal Buhays and Jabal Malaqet) facies. This facies distribution indicates that the Late Cretaceous sea deepened towards the NNW of UAE ( Jabal Qarn El-Barr section). X-Ray diffraction analysis ensured the occurrence of open marine minerals (kaolinite and montmorillonite) within the Late Cretaceous Simsima Formation that outcropped at Jabal Qarn El-Barr. So, the Late Cretaceous Simsima Formation could act as an effective source rock (newly approved) in the northern part of UAE and a prolific reservoir rock in the other parts of UAE. The geochemical analyses also supported the occurrence of source rock facies (high TOC varies from 0.4 to 1.3 wt% and low Pr/Ph ratio) within the Late Cretaceous Simsima Formation. The petrophysical and petrographical investigations proved intercrystalline, vuggy and fracture porosity (varies from 0 to 31%) and permeability ranges from 0 to 850 md for the reservoir facies of Late Cretaceous Simsima Formation. Moreover, the occurrence of anticlinal and thrusted structures (almost acting as sealing faults) within the fractured limestones of the Late Cretaceous Simsima Formation would enhance the probability for hydrocarbon entrapment within these rocks