Shiranish has been studied at Hijran section near Erbil city, NE Iraq. Fifty two thin-sections were prepared to study them under polarized microscope, to determine the petrographic component, organic content and digenetic processes. Rock units subdivided into four rock beds, as follows: dolostone, foraminiferal biomicrite, poorly washed biomicrite and micrite. Vertical succession of Shiranish Formation refers to off-shore quite marine environment.

In the region of the north of Iraq using the method of analyzing thin section microfacies to 38 of rockyslices which were gathered from a place near Aqra city. These slides are divided into seven microfacies depending on lithologcal component and fossils.

1) Dolostone facies.

2)Recrystallized bioclastic wackestone facies.

3) Bioclastic packstone microfacies

4)Sucrosic dolomite facies.

 5) Bioclastic grainstone in microfacies.

 According to water energy, these facies were divided to three zone:

1. a) Low energy environment.
2. b) Transitional zone.
3. c) High energy environment.

      The current research studies the depositional setting of the Jeribe Formation in the south Mosul area of northern Iraq, which is tectonically located in the Low Folded Zone characterized by the deposition of limestone and marly limestone of the Jeribe Formation during the Middle Miocene. Petrography has provided a diversity of fauna such as benthonic foraminifera (Miliolid, Peneroplis sp., Dendritina sp. and Borelis melo curdica) in addition to Red Algae and Mollusca. The Jeribe carbonates were affected by various diagenetic processes such as dolomitization, neomorphism, cementation, anhydritization, compaction and dissolution. Many microfacies have been identified, including lime mudestone, wackestone, packstone and Milioldal

Ten samples were collected from Injana and Mukdadiya Formations, representing 5 samples of fine grain sandstone (F) and 5 samples of very fine grain sandstone (VF). The heavy metals study showed that the opaque mineral recorded the highest percentage in comparison with other heavy metals. While, transparent minerals, including unstable minerals (Amphibole including Hornblend and Glaucophane) and (pyroxene including Orthopyroxene and Clinopyroxene), Metastable minerals including (Epidote, staurolite, Garnet, Kyanite) indicated metamorphic source, Ultrastable minerals (Zircon, Rutile, Tourmaline), Mica group (chlorite, biotite and muscovite). These accumulations indicate that the heavy minerals are derived from mafic igneous and metamorphi

Visualization of subsurface geology is mainly considered as the framework of the required structure to provide distribution of petrophysical properties. The geological model helps to understand the behavior of the fluid flow in the porous media that is affected by heterogeneity of the reservoir and helps in calculating the initial oil in place as well as selecting accurate new well location. In this study, a geological model is built for Qaiyarah field, tertiary reservoir, relying on well data from 48 wells, including the location of wells, formation tops and contour map. The structural model is constructed for the tertiary reservoir, which is an asymmetrical anticline consisting of two domes separated by a saddle. It is found that

     Yamama Formation is an important sequence in southern Iraq. Petrographic analysis was used to determine and analyze the microfacies and pore types. The diagenetic processes and the impacts on the petrophysical properties of the rocks were also identified. The petrographic identification was based on data of 250 thin sections of cutting and core samples from four wells that were supplied by the Iraqi Oil Exploration Company (O.E.C). The present study focuses on the depositional environment and the microfacies analysis of Yamama Formation. The results revealed several types of microfacies, including  peloidal wackestone-packstone, algal wackestone-packstone, bioclastic wackestone-packstone, fo

Thirty-four dolomite and dolomitic limestone samples were collected from Aqra – Bekhma (It is difficult to separate the two formations as they are intervening) Formation in Bekhma Gorge area near Shaqlawa in northern Iraq. Alizarin red - s was used to distinguish calcite from dolomite. The saddle dolomite was recognized as a virtually rough crystalline material with milky-white or rosy color when seen in outcrop. In addition, we observed a pearl luster and a characteristically marred crystal building that is, in principle, described as damaged crystal faces with cleavage planes, while microscopically it appeared as a widespread extinction. The crystal faces, although well advanced, are frequently pavement-like facets.

The outcrop sections of Ora Formation (late Devonian-Early Carboniferous) in the Nazdor and Ora localities at the Northern Thrust Zone of Iraq were selected for this study. Lithologically the Ora Formation composed of clastic and carbonate rocks. The lower part in the Nazdor section cosists of crossbedded quartz arenite sandstone interbedded with successive laminated siltstone and shale. The lithology of the upper part in the Nazdor section and the upper part in Ora section, are composed of mixed silicalcastic (shale, siltstone and sandstone) and carbonate interbedded lithology. The petrographic study shows that the carbonate rocks consist of micrite and sparite groundmass. The skeletal grains include shallow water brachiopods, bryozoans