A geochemical and environmental study was carried out for the sediments of the Southern Neo-Tethys Ocean, represented by the Yamama Formation (Berriasian-Valaganian) in southern Iraq. The formation has a particular reservoir importance. The typical WQ-220 and WQ-280 wells were selected from the West Qurna field. Data of Gamma-ray logs were used for 30 depths of the typical well. Ten core samples were analyzed by X-Ray Fluoresces and total organic matter from both wells. The results showed that shaliness was relatively low, with an average of 16.5%, leading to a decrease in the presence of clay minerals and trace elements because the environment of the Yamama Formation is relatively far away from the coast. Qualitative evaluation of clay minerals was carried out by thorium/potassium ratio, which showed the dominance of illite and smectite. This may be due to an increase in the salinity of the ocean at that time or because potassium bonds are strong enough to resist the diagenesis processes. The origin of shale in the Yamama Formation was studied using the relationship TiO2-MgO+Fe2O3; the sources were passive margin group, oceanic island arc and active continental margin. The redox potential of paleoenvironment was determined by the thorium/uranium ratio, which showed that the beginning of depositional environment was slightly oxidized, but with the increase of sedimentation, it turned into a reduced environment, which indicates a transgression phase of sea level. The results of euxinic affinity, based on the relationship between molybdenum and Total Organic Carbon (TOC), reflect dyoxic facies which is deposited in extremely low but non-zero oxygen content, while the upper was approaching anoxic facies zone. The paleoenvironment of the Yamama Formation was of restricted deep marine water (outer shelf - upper part of the benthic zone) which contained a marine transgression phase because of the opening of Southern Neo-Tethys Ocean in the Valanginian age.
The study of Shiranish Formation rocks in southern part of Iraq at Ansab area well (KH-6)
were carried out. The formation is tongued with tayarat formation, which bounded from top
and bottom, the upper tongue at thickness 49m. and tongued at depth (476-525m.) the lower
tongue at thickness 4m. tongued at (541-537m.).
The rocks of this formation were divided into three sedimentary microfacies:
1- Dolomitized formininferal Wackestone facies.
2- Dolomitized formininferal Mudstone facies.
3- Dolostone facies.
34 slides were investigated depending on mineralogical, compositional and biological
processes and compared diagenesis which reflect open marine shelf at lower part of formation
(F.Z.2) (S.M.F.8), but at the
A 3D geological model for Mishrif Reservoir in Nasiriyah oil field had been invented "designed" "built". Twenty Five wells namely have been selected lying in Nasiriyah Governorate in order to build Structural and petrophysical (porosity and water saturation) models represented by a 3D static geological model in three directions .Structural model showed that Nasiriyah oil field represents anticlinal fold its length about 30 km and the width about 10 km, its axis extends toward NW–SE with structural closure about 65 km . After making zones for Mishrif reservoir, which was divided into 5 zones i.e. (MA zone, UmB 1zone,MmB1 zone ,L.mB1 zone and mB2zone) .Layers were built for each zone depending on petrophysical propertie
... Show MoreIn southern Iraq, the Yamama Formation has been a primary carbonate resource since the Lower Cretaceous era. This study covers Siba Field, which is located in southeastern Iraq. This paper will be devoted to a YC unit of study. The most crucial step in reservoir management is petrophysical characterization. The primary goal of this research is to assess the reservoir features and lithology of the Yamama (YC) Formation in the Siba region. Accessible excellent logs include sonic, density, neutron, gamma-ray, SP, and resistivity readings. The Interactive Petrophysics (IP4.4) program examined and estimated petrophysical features such as clay volume, porosity, and water saturation. The optimum approach was the neutron density and clay vo
... Show MoreThe Mesopotamian marshlands faced a massive destruction from many years and this lead to effect to ecosystem. In this study a survey was made on the physical chemical and heavy metals characteristics and microbiological analysis of AL Chibaish marsh during the two months. Water analyses revealed unacceptable values for almost all physiochemical and biological properties, according to WHO standard limits for drinking water. Almost all major ions and heavy metal concentrations in water showed a distinct decreasing trend at the marsh outlet station compared to other stations. In general, major and minor ions, as well as heavy metals exhibit higher concentrations in location 1 than in location 3. The concentrations of heavy metals in water show
... Show MoreThe middle Cenomanian – early Turonian Mishrif Formation, a major carbonate reservoir unit in southern Iraq, was studied using cuttings and core samples and wireline logs (gamma‐ray, density and sonic) from 66 wells at 15 oilfields. Depositional facies ranging from deep marine to tidal flat were recorded. Microfacies interpretations together with wireline log interpretations show that the formation is composed of transgressive and regressive hemicycles. The regressive hemicycles are interpreted to indicate the progradation of rudist lithosomes (highstand systems tract deposits) towards distal basinal locations such as the Kumait, Luhais and Abu Amood oilfield areas. Transgressive hemicycles (transgressive systems tract deposits)
... Show MoreTwenty sand samples were collected from the sand dunes of Missan fields, Southeastern Iraq. Grain size distribution, mineralogical and chemical composition were studied for the total, medium, and fine-size sand fractions. The grain size analysis shows that the sand is the main component, followed by silt and trace of clay. The predominant grain size of sand is 0.250 to 0.500 mm, which forms more than 57.28 %, which indicates that these dunes were formed under the influence of relatively strong winds and the sedimentary material is close to the source. The light components are quartz, feldspar, and different rock fragments, while the heavy mineral assemblages are composed of opaque minerals, chlorite, mica, and amphiboles.
... Show MoreThe research aims to assess the claystone exposed in the Nfayil Formation (Middle Miocene) for Portland cement (P.C.) manufacturing based on mineralogy and geochemistry. The importance of the study is to avoid the miming of the agricultural soils that are mining now for the cement industry. Claystones of Nfayil Formation and the limestone of the Euphrates Formation were used to design the raw mixture as clay to limestone (1:3). The chemical composition (%) of the designed mixture was calculated using the Alligation Alternative Method (A.A.M.) as CaO (65.52), MgO (1.05), SiO2 (21.65), Al2O3 (7.43), Fe2O3 (2.62), Na2O3+K2O (1.52) and SO3 (0.26), which are suitable for P.C. The lime saturation factor (LSF = 92.8), silica saturation fac
... Show MoreThe aim of this study is to determine and evaluate the units and subunits of Mishrif Formation in Garraf oil field 85 km north of Nasiriyah city depending mainly on the geophysical well logging data and other amiable geological information. The sets of the geophysical well logs data acquired from GA-4, GA- AIP, GA- B8P, GA-3 and GA-5 wells of Garraf oil field are used to determine the petrophysical and lithological properties for each zone in Mishrif Formation to locate, define and evaluate hydrocarbon production from each zone in the reservoir which is also known as formation evaluation. The digitization was done by using Didger software and the interpretations were made using Interactive Petrophysics Program v 3.5 and Petrel software.
... Show MoreWellbore instability problems cause nonproductive time, especially during drilling operations in the shale formations. These problems include stuck pipe, caving, lost circulation, and the tight hole, requiring more time to treat and therefore additional costs. The extensive hole collapse problem is considered one of the main challenges experienced when drilling in the Zubair shale formation. In turn, it is caused by nonproductive time and increasing well drilling expenditure. In this study, geomechanical modeling was used to determine a suitable mud weight window to overpass these problems and improve drilling performance for well development. Three failure criteria, including Mohr–Coulomb, modifie