Basin Analysis of the Late Cretaceous Sediments in UAE

Esam Ahmed Abd El-Gawad¹, Osman Abdelghany Osman², Mostafa Amin Lotfy¹, Wahid Hashim¹, and Mahmoud Mostafa Abu Saima^1
1UAE University, Al-Ain, United Arab Emirates
²UAE University, Al-Ain, United Arab Emirates

The Late Cretaceous is one of the most significant periods in the geological history of the Arabian Peninsula, in view of the major structural, tectonic and stratigraphic events of this age which have affected and controlled the oil potentialities in the region. Such industry–oriented field study is essentially aimed at finding new hydrocarbon prospective horizons and /or areas to be added to the petroleum map of UAE. 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). XRD analysis ensured the occurrence of open marine minerals (illite and montomorlionite) 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 proved) 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.

AAPG Search and Discovery Article #90072 © 2007 AAPG and AAPG European Region Conference, Athens, Greece