The Late Maastrichtian–Danian phosphatic succession prevails as a deposit to the west of Rutbah region, Western Iraq. This is manifested through the lithostratigraphic sections of boreholes (K.H5\6 and K.H 5\8) drilled previously in the area. The succession is mainly composed of phosphate, shale, porcelanite, oyster and foraminiferal carbonate lithofacies belonging to Digma and Akashat formations. Three facies associations are distinguished during the study: the phosclast planktonic (FA1) that dominates the outer ramp, the phosclast foraminiferal (FA2) that dominates the mid ramp, and the quartz dolomitic phosclast (FA3) present in the inner ramp. These facies’ associations are differentiated into se

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 Early Jurassic (Liassic) sequence crops out in numerous anticlines of the high folded zone of north and north-east Iraq and in the Rutba subzone (including Ubaid Formation) in west Iraq. The present study deals with siliciclastic / carbonate rocks of the 58 m-thick Ubaid Formation at Zor Hauran valley in south western Iraq. The formation consists of two parts; the lower part is composed of pebbly coarse sandstone and greenish to yellowish soft marl alternated with marly dolostone, while the upper part is characterized by light brown, well bedded dolostone, with stromatolite structure in some locations. Oval, light to dark brown nodules of chert are also present.

     A detailed field lithological desc

     This study aims to overcome the unexpected hydrocarbon non-potentiality detected in the upper Alam El-Bueib (I to IIIE) and justify the hydrocarbon accumulation within Alam El-Bueib (IIIG) at the Emry oil field, also, it is important to highlight the importance of fault seal analysis and the impact of Matruh canyon as a seal. Seismic interpretation and 3D structural framework are carried out using the fault-seal analysis technique for fault no.1 (F1). To assess the fault zone's capacity to be defined as either seal or leakage. Litho-facies juxtaposition diagram (Allan diagram) and Shale Gouge Ratio (SGR) were generated. It is concluded that the possible reason for the dry reservoir of the upper part of Alam El Bueib (Alam El Bue

The Hartha Formation is one of the important formations deposited during Late Campanian age.

The present study deals with four boreholes (EB-53, 54, 55 and 56) within the East Baghdad oil field to diagnoses the microfacies and interpret the depositional environments.

Six major microfacies were recognized in the succession of the Hartha Formation. Their characteristic grain types and depositional texture enabled the recognition of paleoenvironment. There are Orbitoides  wackestone-packstone , Orbitoides - miliolid wackestone, Peloidal and Pellets - echinoderm wackestone to packstone, Peloidal wackestone to packstone, Pelletal wackestone to packstone, and Planktonic foraminifera wackestone-packstone.

Four assoc

     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

Six main microfacies are identified which are Lime Mudstone, Bioclastic Wackeston, Bioclastic Packstone-Wackestone, Bioclastic Wackestone- Mudestone, Pelagic Mudstone–Wackestone, Bioclastic Packstone -Grainston Microfacies in addition to their associated depositional environment. The diagenesis process have affected the Mishrif rocks and played a role in deteriorating reservoir porosity in well Ga-2 and enhancing it in well Ga1,3.These processes include: cementation, micritization, recrystallization,dissolution,compaction pressure solution and dolomitization.

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

This paper includes studying the microfacies evalution of Mauddud Formaion in
four wells(Rt-2, Rt-5, Rt17 and Rt-19). Seventy-seven(77) sampels were collected
of above mentioned wells. Based on fossil content of the samples under study, four
main microfacies were identified: packstone , wakestone , grainstone and lime
mudstone microfacies ,which deposited in shallow open marine and restricted
marine environments. Petrographic examination of thin section indicated that
diagenesis vary in intensity from one site to another, such as dissolution,
cementation, compaction, dolomitization and micritization, which led to the
improvement and deterioration of porosity. The dominant pore types are vuggy,
interparticle and