Exploratory activities carried out by oil companies in the latter half of the past
century proved the existence of voluminous reserve of oil and gas in the
southwestern area of Iraq. In view of this, it seemed more than prudent to add a new
knowledge to that currently existing about the subsurface lithostratigraphy of this
area. As a first step in fulfilling this mission, this paper will attempt to do so by
covering the time interval from the Upper Cretaceous to the Neogene. In turn, this
effort had entailed both the description of about 4707 metres of fully recovered
cores, plus the subjection of more than 4000 samples to existing petrologic analyses.
Findings worth mentioning does include the observation that wi

This study deals with seismic structural and stratigraphic interpretation that applied on the East Razzaza (central of Iraq) area, by using 2D seismic data from Oil Exploration Company. Three main seismic reflectors are picked. These reflectors are Zubair, Yamama and Gotnia Formations, which were defined by using petrophysical well logs and synthetic traces that calculated from sonic- logs of the wells East Baghdad-1(Eb-1) and West kifl-1(Wk-1) using Geoframe program, to suggest a stratigraphic model for them. Structural maps of formations are prepared to obtain the location and direction of the sedimentary basin and shoreline. Seismic interpretation of the area approves the presence of some stratigraphic features in the studied formatio

During the Maastrichtian, the rudists and benthic foraminifera of Aqra Formation underwent two major radiations, the first beginning in early Early Maastrichtian and peaking in the late Early Maastrichtian, and sconed extending from the early Late Maastrichtian to a late Late Maastrichtian peak.The radiations were punctuated and separated by prominent extinction episodes, fit with global Maastrichtian mass extinction.The high level of rudist, endemism [90%] allows definition of true regional origination and extinction pattern; these may represent global pattern for rudists. Radiation and extinction patterns in the northern Iraq [Kurdistan Region] can be variously related to relative sea level fluctuation and the rate of food and clastic

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

     This research focused up on the Seismic reflection study of a 268.7 km² area located in the central of Iraq within the Karbala province (Kifl area). The seismic data were reprocessed by Anadarko Petroleum Corporation and its partners Dome International and Vitol with OEC in 2005, the result of processing works has improved the quality of seismic sections in most of the study area.  The study area was interpreted by using 3-D seismic data from the Oil Exploration Company. By studying the seismic sections and applying seismic attributes (instantaneous phase) Faults were picked across 3D seismic volume of the studied reflectors. The study area affected by a major fault and minor normal faults, Two fa

Seismic data interpretation study has been done for Mishrif Formation in Nasiriyah oil field at the southern part of Iraq in order to update the structural image of Mishrif reservoir which is currently the main unit bearing the oil in subsurface area covered about (447) km2. This study is achieved by using Petrel, IP, and other approval software. Seismic to well tie method in conventional qualitative interpretation used to re-identify the top and bottom of the Mishrif reservoir which converted into structural depth maps and then followed by constructing and developing 3-D structural model helped to understand the vertical and lateral thickness extensions heterogeneity of Mishrif Formation in the field. The cap rock (CRI) has thickness ra

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

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

The Late Cretaceous-Early Paleocene Shiranish and Aliji formations have been studied in three selected wells in Jambur Oil Field (Ja-50, Ja-53, and Ja-67) in Kirkuk, Northeastern Iraq. This study included lithostratigraphy and biostratigraphy. The Late Campanian-Maastrichtian Shiranish Formation consist mainly of thin marly and chalky limestone beds overlain by thin marl beds, with some beds of marly limestone representing an outer shelf basinal environment, the unconformable contact with the above Middle Paleocene-Early Eocene Aliji Formation contain layers of limestone with marly limestone and chalky limestone which represents an outer shelf basinal environment. Five Biozones in the Shiranish Formation were determined which are: 1

In the Rumaila oilfields in southern Iraq, the Zubair Formation was deposited in a shallow environment as three main facies, delta plain, backshore, and delta front depositional conditions indicating a transition from delta front and delta plain to a highstand level due to the finning upward mode. The facies of the Zubair clasts show well-sorted quartz arenite sandstone, poorly sorted quartz arenite sandstone, clayey sandstone that has not been properly sorted, sandy shale, and shale lithofacies. The minor lithofacies were identified using well-logging methods (gamma ray, spontaneous potential and sonic logs) and petrography. The Zubair clasts are of transition environment that appears to be transported from freshwater and deposited