Integrated stratigraphic study of the Cretaceous petroleum-potential succession, Sulaimani area, Kurdistan, Iraq

Volume 1 , Issue 1 , January 2016 , Pages 391-418

Authors

¹ Department of geology, University of Sulaimani, Kurdistan , Iraq

² Geological survey & Mineral Exploration Directorate, Sulaimani, Kurdistan, Iraq

The Cretaceous sequence of Kurdistan Region of northeast Iraq form an important

petroleum system in housing potential source rocks such as the Balambo, Sarmord and

Shiranish Formations. It also includes an important reservoir rocks supplied with good

secondary porosity such as the Qamchuqa and Kometan Formations. This study

examined surface and subsurface sections of these units from Sulaimani area of

Kurdistan region of northeast Iraq using stratigraphic analysis, microfacies

investigations, lithostratigraphic correlation in an attempt to characterize these units at

this area and to give an insight regarding the stratigraphic architectural impact on the

development of their petroleum system. Microfacies analyses show the occurrences of

deep to shallow marine facies. It ranges between basinal foraminiferal- Oligostiginal

grainstone to wakestone (Balambo, Sarmord, Kometan, Shiranish, and parts of the

Tanjero Formations) to bioclastic -foraminiferal packstone to wackestone of the

Qamchuqa Formation. The Dolostone part of the Qamchuqa Formation is characterized

by medium to coarse crystalline planar-e to planar-s type mosaic.

The Late Cretaceous units of the Kometan, Shiranish, and Tanjero Formations in both

outcrop and neighboring subsurface sections, show little stratigraphic differences within

the study area from elsewhere in Kurdistan Region. The Early Cretaceous units of the

Balambo, Sarmord and Qamchuqa Formations (which are the focus of this study),

however, show lateral and vertical stratigraphic variations in lithology and thicknesses in

both northward and westward directions. The basic difference is the change of the deep

marine Oligostiginal marly limestone of the Balambo Formation into the dolomitized

platform carbonates of the Qamchuqa Formation in both directions. This lateral changes

passes through a transitional zone of interfingering relation, which is up to 15Km in

width. This zone plays an important role in developing the Cretaceous petroleum system

of the area.

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