Microfacies study of the Neogene sequences and determination of sedimentary environments in the Jambour oil field / Kirkuk

Abstract

The current research deals with microfacies study of the four wells drilled in the area south-east of Kirkuk within Jambour oil field and these are wells Jambour Ja-42 ,Ja-55,Ja-62 and Ja-66. The study included the bed of a Basal anhydrite cycle (Aquitanian) and configurations Serikagni, Euphrates and  Dhiban Formation  from early Miocene  second secondary cycle (Burdigalian) and Jeribe Formation from secondary middle Miocene cycle (Langhian).

The petrographic study showed that the most important components of limestone is skeletal grains, non-skeletal grains , cement and matrix.  The current study described sedimentary facies, which are divided into: - mudstone facies , wackestone facies , packstone  facies  and grainstone facies and these microfacies have been divided into submicrofacies. The facies changes within the studied formations have been identified on the depositional environment and put their environmental models. Overall, the Burdigalian cycle characterized by swallowing upward , which began transgression making several and different sedimentary environment , which lasted from pelagic environment formation(Serikagni Formation) and to shallower environment(Euphrates Formation), which ended with marine regression (evaporites of Dhiban  Formation) in the basin was originally inherited from the basin of  Euphrates and Serikagni Formations. The lower part of Langhian cycle represented by the Jeribe Formation also affected by another transgression.