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Wellbore instability management using geomechanical modeling and wellbore stability analysis for Zubair shale formation in Southern Iraq
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Abstract<p>Wellbore 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, modified Lade, and Mogi–Coulomb, were used to predict a safe mud weight window. The geomechanical model was constructed using offset well log data, including formation micro-imager (FMI) logs, acoustic compressional wave, shear wave, gamma ray, bulk density, sonic porosity, and drilling events. The model was calibrated using image data interpretation, modular formation dynamics tester (MDT), leak-off test (LOT), and formation integrity test (FIT). Furthermore, a comparison between the predicted wellbore instability and the actual wellbore failure was performed to examine the model's accuracy. The results showed that the Mogi–Coulomb failure and modified Lade criterion were the most suitable for the Zubair formation. These criteria were given a good match with field observations. In contrast, the Mohr–Coulomb criterion was improper because it does not match shear failure from the caliper log. In addition, the obtained results showed that the inappropriate mud weight (10.6 ppg) was the main cause behind wellbore instability problems in this formation. The optimum mud weight window should apply in Zubair shale formation ranges from 11.5 to 14 ppg. Moreover, the inclination angle should be less than 25 degrees, and azimuth ranges from 115 to 120 degrees northwest-southeast (NE–SW) can be presented a less risk. The well azimuth of NE–SW direction, parallel to minimum horizontal stress (Shmin), will provide the best stability for drilling the Zubair shale formation. This study's findings can help understand the root causes of wellbore instability in the Zubair shale formation. Thus, the results of this research can be applied as expenditure effectiveness tools when designing for future neighboring directional wells to get high drilling performance by reducing the nonproductive time and well expenses.</p>
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Publication Date
Mon Aug 05 2024
Journal Name
Pharmacia
A validated spectrophotometric analysis for simultaneous estimation of vincristine sulfate and bovine serum albumin in pure preparations using Vierordt’s method
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The novel Vierordt’s approach, or simultaneous equation method, was created and validated for the concurrent determination of vincristine sulfate (VCS) and bovine serum albumin (BSA) in pure solutions utilizing UV spectrophotometry. It is simple, precise, economical, rapid, reliable, and accurate. This method depends on measuring absorbance at two wavelengths, 296 nm and 278 nm, which correspond to the λmax of VCS and BSA in deionized water, respectively. The calibration curves of VCS and BSA are linear at concentration ranges of 10–60 μg/mL and 200–1600 μg/mL, with correlation coefficient values (R2) of 1 and 0.999, respectively. The limits of detection (LOD) and quantification (LO

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Publication Date
Tue Sep 01 2020
Journal Name
Al Kut Journal Of Economics And Administrative Sciences
Economic Analysis of The Most Important Factors Affecting Sustainable Agricultural Development in Iraq for The Period 2000-2017
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Publication Date
Sun Jan 30 2022
Journal Name
Iraqi Journal Of Science
Convergence and Stability of Iterative Scheme for a Monotone Total Asymptotically Non-expansive Mapping
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    In this work, we introduce Fibonacci– Halpern iterative scheme ( FH scheme) in partial ordered Banach space (POB space) for monotone total asymptotically non-expansive mapping (, MTAN mapping) that defined on weakly compact convex subset.  We also  discuss the results of weak and strong convergence for this scheme.

 Throughout  this work, compactness condition of m-th iterate  of the mapping for some natural m is necessary to ensure strong convergence, while Opial's condition has been employed to show weak convergence. Stability of FH scheme is also  studied. A numerical comparison is provided by an example to show that FH scheme is faster than Mann and Halpern iterative

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Publication Date
Sat Jun 27 2020
Journal Name
Iraqi Journal Of Science
Stability And Data Dependence Results For The Mann Iteration Schemes on n-Banach Space
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Let  be an n-Banach space, M be a nonempty closed convex subset of , and S:M→M be a mapping that belongs to the class  mapping. The purpose of this paper is to study the stability and data dependence results of a Mann iteration scheme on n-Banach space

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Publication Date
Tue Jun 01 2021
Journal Name
Iop Conference Series: Materials Science And Engineering
An Experimental Research on Design and Development Diversified Controllers for Tri-copter Stability Comparison
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Abstract<p>The drones have become the focus of researchers’ attention because they enter into many details of life. The Tri-copter was chosen because it combines the advantages of the quadcopter in stability and manoeuvrability quickly. In this paper, the nonlinear Tri-copter model is entirely derived and applied three controllers; Proportional-Integral-Derivative (PID), Fractional Order PID (FOPID), and Nonlinear PID (NLPID). The tuning process for the controllers’ parameters had been tuned by using the Grey Wolf Optimization (GWO) algorithm. Then the results obtained had been compared. Where the improvement rate for the Tri-copter model of the nonlinear controller (NLPID) if compared with </p> ... Show More
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Publication Date
Thu Jan 20 2022
Journal Name
Iraqi Journal Of Science
Enhance the delineation of masked structures in southern Iraq by applying the Biharmonic operator to their gravity field.
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The gravity field of southern Iraq shows steep gradient of regional trend. The gravity contours over the anticline structures in this area do not show the closure characteristic of these structures. The effect of lateral density variation for Hormuz Salt complicates the case in the area. Higher derivatives are one of the means that have been used to remove the effect of such regional gravity variations, which can easily mask significant structures. Biharmonic Operator is used to delineate these distort structures, follow their extent and at the same time distinguish new features. The Biharmonic operator manipulation has ability to suppress the effect of regional and enhance the local anomalies. The problem with higher derivatives operati

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Publication Date
Thu Mar 17 2016
Journal Name
International Journal Of Computer Applications
Analysis of Wind Speed Data and Annual Energy Potential at Three locations in Iraq
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Publication Date
Fri Nov 01 2019
Journal Name
Advances In Intelligent Systems And Computing
Analysis of the Relationship Between Traffic Accidents with Human and Physical Factors in Iraq
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Publication Date
Fri Jun 30 2023
Journal Name
Iraqi Journal Of Science
Phylogenetic Analysis of Klebsiella pneumoniae Isolated from Nosocomial and Community Infection in Diyala, Iraq
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     The biological diversity of Klebsiella pneumoniae (K. pneumoniae) has widely been reported to be associated with pathological progress in severe nosocomial and community-acquired infections. 250 clinical specimens included sputum, urine and swabs from wound and burns samples were collected from Al-Batool Teaching Hospital (38.4%), Baqubah Teaching Hospital (61.6%) and private laboratories in Baqubah and Diyala, Iraq. Positive rates of nosocomial acquired infection were sputum 98%, urine 96%, and swabs from wound and burns 94%, while positive rates of community acquired infection were sputum 60%, urine 60%, and swabs wound and burns 30%. Positive rates of nosocomial and community acquired infections were 96% and 48%, res

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Publication Date
Thu Oct 01 2015
Journal Name
Journal Of Economics And Administrative Sciences
Analysis of the causal relationship between agricultural imports and some economic variables in Iraq
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Foreign trade receives a good deal of economists' attention for its active contribution to economic growth, and imports of goods and services that could not be produced locally constitute an important share of the local economy.  Agricultural imports constitute an important share of the total imports due to their role in fulfilling the needs of local markets; however, the agricultural sector in Iraq contributes no more than a limited share of the country's need, which has encouraged the import of a variety of fruits, vegetables and strategic crops and different types of red and white meat. For the sake of identifying the factors affecting the demand on agricultural imports in Iraq, the following factors has been analyzed: th

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