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joe-2783
Experimental Evaluation of Stability and Rheological Properties of Foam Cement for Oil Wells
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Oilwell cementing operations are crucial for drilling and completion, preserving the well's productive life. However, weak and permeable formations pose a high risk of cement slurry loss, leading to failure. Lightweight cement, like foamed cement, is used to avoid these difficulties. This study is focused on creating a range of foamed slurry densities and examining the effect of gas concentration on their rheological properties. The foaming agent and foam stabilizer are tested, and the optimal concentration is determined to be 2% and 0.12%, respectively, by the weight of the cement.

Furthermore, the construction of samples of foam cement with different densities (0.8, 1.0, 1.2, 1.4, and 1.6) g/cc is performed to find the relation with different volumetric percentage gas in foamed cement slurry (57.5, 47, 36, 25.5, and 15%). The relationship between rheological properties and foam quality is discussed, as the presence of gas plays a significant role in enhancing rheological properties. The rheology of foam cement increases proportionally with increasing foam quality, especially the plastic viscosity, which is 26 cp at 0% foam quality and 50 and 65 cp at 15% and 57.5% foam quality, respectively. Also, yield points increase as foam quality improves. Therefore, it is feasible to exclude certain cement additives that increase viscosity.

 

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Publication Date
Fri Jul 08 2022
Journal Name
Innovation Of Businesses, And Digitalization During Covid-19 Pandemic
The Impact of Political Stability and Macroeconomic Variables on Foreign Direct Investment in Turkey
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Foreign direct investment (FDI) is one of the most practical types of foreign investment. FDI contributes to job creation, foreign exchange earnings and national income escalation, improving semi-skill and skilled labor. Based on our knowledge, this paper is the first study attempting to investigate the effect of political stability on the FDI in Turkey using an econometric approach. Achieving this objective, a co-integration analysis was conducted between the FDI and its determinants in the short-run and long-run including “macroeconomic indicators” and “Political Stability (PS)” in Turkey. Using annual data from 1974 to 2017 via Auto-Regressive Distributed Lag (ARDL) model. The results confirm the positive correlation betwe

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Publication Date
Mon Nov 01 2021
Journal Name
Proceedings Of First International Conference On Mathematical Modeling And Computational Science: Icmmcs 2020
Study the Stability for Ordinary Differential Equations Using New Techniques via Numerical Methods
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Nonlinear differential equation stability is a very important feature of applied mathematics, as it has a wide variety of applications in both practical and physical life problems. The major object of the manuscript is to discuss and apply several techniques using modify the Krasovskii's method and the modify variable gradient method which are used to check the stability for some kinds of linear or nonlinear differential equations. Lyapunov function is constructed using the variable gradient method and Krasovskii’s method to estimate the stability of nonlinear systems. If the function of Lyapunov is positive, it implies that the nonlinear system is asymptotically stable. For the nonlinear systems, stability is still difficult even though

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Publication Date
Fri Feb 26 2021
Journal Name
Iraqi Journal Of Science
Determination the Optimum Conditions of the Activity and Stability of Lipase Extracted from Sunflower Germinated Seeds
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The present study was conducted to determine the optimum conditions required for lipase enzyme activity extracted from germinated sunflower seeds, including temperature, pH, agitation, time of incubation, enzyme concentration, substrate type, and concentrations of mineral salts and EDTA. Optimum pH, temperature and time of incubation required for lipase stability were also determined. The results showede optimum lipase activity (3.251U/ml) wasund at 30 ÌŠC and pH 7 after 20 minutes of incubation when using 1 ml lipase enzyme with 0.02 ml of CaCl2 (10 mM) at 100 rpm of agitation and in the presence of olive oil as the substrate for enzyme reaction. EDTA appeared to have inhibitory effects, while Ca+2 and Mg+2 have stimulatory effec

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Publication Date
Mon Dec 31 2012
Journal Name
Al-khwarizmi Engineering Journal
Experimental Investigation of Using Evaporative Air Cooler for Winter Air-Conditioning in Baghdad
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This paper presents an efficient methodology to design modified evaporative air-cooler for winter air-conditioning in Baghdad city as well as using it for summer air-conditioning by adding a heating process after the humidification process. laboratory tests were performed on a direct evaporative cooler (DEC) followed by passing the air on hot water through heat exchanger placed in the coolers air duct exit. The tests were conducted on the 2nd of December /2011 when the ambient temperature was 8.1°C and the relative humidity was  (68%). The air flow rate is assumed to vary between 0.069 to 0.209 kg/s with constant water flow rate of 0.03 kg/s in the heat exchanger. The performance is reported in terms of effectiveness of DEC, satura

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Publication Date
Thu Oct 06 2022
Journal Name
Advances In Systems Science And Applications
Stability and Bifurcation of a Delay Cancer Model in the Polluted Environment
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It is well known that the spread of cancer or tumor growth increases in polluted environments. In this paper, the dynamic behavior of the cancer model in the polluted environment is studied taking into consideration the delay in clearance of the environment from their contamination. The set of differential equations that simulates this epidemic model is formulated. The existence, uniqueness, and the bound of the solution are discussed. The local and global stability conditions of disease-free and endemic equilibrium points are investigated. The occurrence of the Hopf bifurcation around the endemic equilibrium point is proved. The stability and direction of the periodic dynamics are studied. Finally, the paper is ended with a numerical simul

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Publication Date
Wed Sep 01 2021
Journal Name
Applications And Applied Mathematics: An International Journal (aam)
Stability and Bifurcation of a Cholera Epidemic Model with Saturated Recovery Rate
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In this paper, a Cholera epidemic model is proposed and studied analytically as well as numerically. It is assumed that the disease is transmitted by contact with Vibrio cholerae and infected person according to dose-response function. However, the saturated treatment function is used to describe the recovery process. Moreover, the vaccine against the disease is assumed to be utterly ineffective. The existence, uniqueness and boundedness of the solution of the proposed model are discussed. All possible equilibrium points and the basic reproduction number are determined. The local stability and persistence conditions are established. Lyapunov method and the second additive compound matrix are used to study the global stability of the system.

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Publication Date
Tue May 16 2023
Journal Name
Steel And Composite Structures
Thermal buckling and stability of laminated plates under non uniform temperature distribution
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Stability of laminated plate under thermal load varied linearly along thickness, is developed using a higher order displacement field which depend on a parameter “m”, whose value is optimized to get results closest to three-dimension elasticity results. Hamilton, s principle is used to derive equations of motion for laminated plates. These equations are solved using Navier-type for simply supported boundary conditions to obtain non uniform critical thermal buckling and fundamental frequency under a ratio of this load. Many design parameters of cross ply and angle ply laminates such as, number of layers, aspect ratios and E1/E2 ratios for thick and thin plates are investigated. It is observed that linear and uniform distribution of

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Scopus
Publication Date
Fri May 01 2020
Journal Name
Journal Of Engineering
Chemical and Thermal Investigation on Stability of Tanuma Formation Using Different Additives with Drilling Fluids
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Wellbore stability is considered as one of the most challenges during drilling wells due to the
reactivity of shale with drilling fluids. During drilling wells in North Rumaila, Tanuma shale is
represented as one of the most abnormal formations. Sloughing, caving, and cementing problems
as a result of the drilling fluid interaction with the formation are considered as the most important
problem during drilling wells. In this study, an attempt to solve this problem was done, by
improving the shale stability by adding additives to the drilling fluid. Water-based mud (WBM)
and polymer mud were used with different additives. Three concentrations 0.5, 1, 5 and 10 wt. %
for five types of additives (CaCl2, NaCl, Na2S

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Publication Date
Sat Aug 31 2024
Journal Name
Iraqi Geological Journal
Microfacies Analysis and Evolution of Porosity of the Albian-Early Cenomanian Mauddud Formation from Selected Wells in Ratawi Oilfield, Southern Iraq
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Mauddud Formation (Albian stage-the Early Cretaceous) is an important oil reservoir in Ratawi field of southern Iraq. Four wells, R T-2, R T-3, R T-6, and R T-7, located 70 km northwest of Basra, were selected to study microfacies properties and petrophysical associations with the probability of oil production. Seventy-seven core samples are collected, and thin sections for petrographic analysis. The self-potential, Gamma-ray, resistivity, and porosity logs are used to determine the top and bottom of the Mauddud Formation. Water saturation of the invaded and uninvaded zones, shale volume, and porosity were calculated. The study area results showed that the quantity of shale is less than 15% for most of the wells, and the dominant po

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Publication Date
Sun Oct 31 2021
Journal Name
Iraqi Geological Journal
Estimation of Mechanical Rock Properties from Laboratory and Wireline Measurements for Sandstone Reservoirs
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Mechanical rock properties are essential to minimize many well problems during drilling and production operations. While these properties are crucial in designing optimum mud weights during drilling operations, they are also necessary to reduce the sanding risk during production operations. This study has been conducted on the Zubair sandstone reservoir, located in the south of Iraq. The primary purpose of this study is to develop a set of empirical correlations that can be used to estimate the mechanical rock properties of sandstone reservoirs. The correlations are established using laboratory (static) measurements and well logging (dynamic) data. The results support the evidence that porosity and sonic travel time are consistent i

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