The sequence in the upper part of the Balambo Formation is composed mainly of limestone alternating with marly limestones and dark grey shale in the Bosheen section (eastern Sulaymaniyah, northeastern Iraq) and has been studied in terms of its rare earth element (REE) content. The REEs are very low compared to modern marine sediments. They are depletion in LREEs, and enrichment in HREEs and (La/Yb)_N in the studied rocks, indicating that these sediments retained the REEs pattern of marine waters. The negative Ce anomaly reflects direct sedimentation from marine waters under anoxic conditions with the contribution of terrigenous clays. The positive correlation of ∑REEs with Al, Ti, and Y, and the negative correlation of ∑REE

The current study summarized the construction of a three-dimensional geological model of the Aquitanian sediments age, which represented by the Euphrates and Serikagni formation in Ajeel Oil Field, where Ajeel Oil Field has structural closure towards northwest - southeast. Sedimentary of the current study consist of limestone, dolomitic limestone, dolomite (compose of skeletal grains, non-skeletal grains and cement) and the appearance of some anhydrite rocks.

     The petrographic study of the Euphrates Formation were prepared using a thin section of wells (Aj-1, Aj-4, Aj-5, Aj-6 and Aj-7), Previous studies and geological reports, as well as use well logs data  in the statistical analysis by Petrel softwa

The Zubair Formation is the most significant sandstone reservoir in Iraq which deposited during the Barremian. The study area is located in the central part of Iraq at the Kifl oil field, in the northern part of the Mesopotamian Zone.

The petrographic study showed that quartz mineral is the main component of the sandstone in Zubair Formation with very low percentage of feldspar and rare rock fragments to classified as quartz arenite sandtone. There are five lithologic changes (lithofacies) that have characterized the studied succession: - well sorted quartz arenite, poorly sorted quartz arenite, poorly sorted graywacke, sandy shale, and shale.  These lithofacieses were deposited in the deltaic environments as three associate

Upper Cretaceous Oceanic Red Beds (CORBs) are pelagic sediment
deposits that deposited in the Upper Cretaceous basin, with widespread in
part of the world as well as in Iraq. This research investigates the deposition
of cyclic marl and marly limestone CORBs of six selected sections at the
active southern margin of the Tethys during the Late Campanian -
Maastrichtian with petrography, microfacies, and depositional environment.
As this study was not a consideration in the past, so decided to visit and
identify all exposure areas of the Upper Cretaceous period rocks are visited.
This study involved two fields touring reconnaissance extended from
Darbandikhan city in the east south to Shiranish Village in the west

The present study deals with the biostratigraphy and depositional environment of
(Late Turonian – Early Campanian) represent dy Khasib, Tanuma and Saadi
Formations in well Agel -12- Northeastern Tikrite. Determination of three
microfacies in Khasib, one microfacies in Tanuma and three microfacies in Saadi
Formations. Depending on microfacies the paleoecologe of Khasib Middle shelf –
Upper Bathyal environment, Tanuma Shelf Margin environment and Saadi
Formations sediment in Middle shelf – Upper Bathyal. Twenty planktic foraminiferal species belonging to eight genera have been identified within the
studied well.
Depending on the stratigraphic distribution of planktic foraminiferal species, the
succession wa

Fifteen samples of limestone, marls and, clay from the Fat'ha Formation are obtained from the location of Bashiqa village, Bashiqa anticline, Northeastern Iraq. A detailed investigation is carried out, during which twenty-four species of calcareous nannofossils identified, twenty- one are descried from other regions while three are left under an open name because of lack of material or insufficient samples. Besides, seventeen species of Ostracoda fossils were picked and diagnosed, including two subspecies, belonging to ten genera, and four subgenera.

The recorded calcareous nannofossil assemblages include two biozones which are from the lower to the upper part of the section: (1)  Helicosphaera ampliaperta Interval  Bio

The Pila Spi formation composed of seven lithotypes; carbonates (dolomite and
dolomitic limestone), marl, shale/claystone, red argillaceous mudstone, sandstone,
carbonate breccias and debris flow, which are arranged in repeated cycles of mixed
siliciclastic-calciturbidites in a range of gravity-flow regime in the Koi Sanjaq area.
Sedimentologic and facies evidences suggest developed marine environment for the
Pila Spi Formation. Facies analysis and associated sedimentary structures including
graded beddings decide turbidity and gravity flow regime origin of the rocks.
Marine environment is supported by the identifying glauconite and fossils types,
which is reported here for the first time rather than lagoon enviro

Three formations were studied from seven outcrops extend from Surdash to
Shaqlawa (Cenomanian – Santonian), they comprise Dokan, Gulneri and Kometan
Formations. Four microfacies and eight submicrfacies are identified depending on
this microfacies, we determine the depositional environments. Dokan Formation is
deposited in open-marine deep shelf environment; it could be deposited at deeper
shelf to slope and basinal settings. While Gulneri Formation deposited in open sea
shelf, as well as at outer shelf settings, the sediments consist of organic–carbon rich
black shale and consider a record of the ocean anoxic event 2, Kometan Formation
represent pelagic sediments characterize the deep-marine basins in open mar

Records of two regionalized variables were processed for each of porosity and permeability of reservoir rocks in Zubair Formation (Zb-109) south Iraq as an indication of the most important reservoir property which is the homogeneity , considering their important results in criterion most needed for primary and enhanced oil reservoir .Z and F tests that were calculated for the two above mentioned properties of pair units of Zubair Formation have shown the difference in depositional energy and different diagenesis between units IL and AB , DJ and AB , and the similarity in grains size , sorting degree , depositional environment and pressure gradients between IL and AB units , LS and IL units ; also the difference in the properties above betw