The influence of wettability and carbon dioxide injection on hydrocarbon recovery

This study can be divided into two sections. First, a detailed study of petrophysical properties and the impact of wettability is performed on cores from a producing heterogeneous carbonate reservoir from the Middle East. Second, a comparison between different injection schemes (waterflooding, gas injection, WAG and CO2 injection) for enhanced oil recovery is made for another giant carbonate reservoir in the Middle East. Knowledge of the wettability of a reservoir rock and its influence on petrophysical properties is a key factor for determining oil recovery mechanisms and making estimates of recovery efficiency. A full suite of experiments on well-characterised systems, including sandpacks, sandstones and carbonate cores, was performed to measure capillary pressure, relative permeability, NMR response and resistivity index. Cores aged in crude oil, with different wettability were studied. As a preliminary step to investigate the effect of wettability on heterogeneous carbonates from the Middle East, sandpack and sandstone samples were first tested because: 1) these samples are known to be quite homogeneous and of a wettability that can be controlled; 2) To test our experimental methods; and 3) to serve as a dataset for modelling studies. First, the static (porosity and permeability) and dynamic (initial water saturation and residual oil saturation) properties of Leavenseat (LV60) and Ottawa (F-42) sandpacks were measured. The formation factor and NMR response for these sandpacks were also determined. These experimental measurements have served as a benchmark for pore-modelling studies that have reproduced the experimental data. Fontainebleau sandstones have also been used as a benchmark in the industry because of its relatively simple pore structure. Mercury injection capillary pressure (MICP) measurements were performed on this sandstone. The MICP experimental measurements showed very low pore volume values, indicating very tight (consolidated) samples. These samples had a diameter of less than 0.02 m which made the experiments quite difficult. Once we had confidence in the experimental methodology, five carbonate samples from a typical Middle East reservoir were imaged and cleaned in order to render them more water wet. Conventional and special core analyses were performed on all the samples. The pore throat distribution from capillary pressure was successfully compared with the pore size distribution inferred from the NMR T2 relaxation curve. Formation resistivity factor and the formation resistivity index were also measured. Capillary pressure and relative permeability curves were measured using refined oil and synthetic formation brine. Then the samples were aged in crude oil from the same field at elevated temperature (120oC) and underwent the same experiments to evaluate the influence of wettability changes on these properties. The experimental data show that there is a significant difference in the relative permeability and capillary pressure of the cleaned and aged samples; the results are explained in terms of the pore-scale configurations of fluids. In contrast, electrical resistivity did not encounter significant changes for different wettability, suggesting that electrical properties in these carbonates are mainly affected by the porosity that remains water-wet, or is only neutrally-wet. This conclusion is supported by the significant displacement that is observed in the aged sample at capillary pressures close to zero. We show that wettability, imbibition capillary pressure and relative permeability have major impact on the waterflood sweep efficiency and hence on the distribution of remaining oil saturation. An incorrect understanding of the distribution of remaining oil saturation may lead to ineffective reservoir management and IOR/EOR decisions. The second part of this thesis is to assess the efficacy of CO2 injection into carbonate oil fields. The reservoir under study is a layered system. The reservoir consists of two main units, i.e. a lower zone of generally low permeability layers and an upper zone of high permeability layers inter-bedded with low permeability layers; the average permeability of the upper zone is some 10-100 times higher than that of the Lower zone. Under waterflooding, the injected water tends to flow through the upper zone along the high permeability layers and no or very slow cross flow of water into the lower zone occurs, resulting in very poor sweep of the lower zone. There is significant scope for improving oil recovery from such type of heterogeneous mixedwet carbonate reservoirs. The apparent impediment to water invading the bottom strata prompts suggests that a miscible fluid could be Injected into the lower zone. We conducted a series of core-flood experiments to compare the performance of different displacement process: waterflooding, hydrocarbon gas flooding and wateralternate gas (WAG) and compared them with CO2 injection. We show that the local displacement efficiency for CO2 flooding is approximately 97% - much higher than that obtained from waterflooding or hydrocarbon gas injection, due to the development of miscibility between CO2 and the oil. We use the results to discuss the potential of CO2 injection for storage and enhanced oil recovery in the Middle East carbonate reservoir discussed above, and proposes further research to develop a fuller understanding of the subsurface behavior of CO2

Social Studies Teaching In Oman : Teachers' Concerns And Levels Of Use In The Adoption Of Student-Centered Teaching Approach [LB1584.A2 A266 2007 f rb].

Kajian ini adalah untuk menyelidik keperihatinan dan tahap Penggunaan guru-guru Pengajian Sosial dalam pengambilan dan pengamalan pendekatan pengajaran berpusatkan pelajar (S-CTA) dalam pengajaran dan pembelajaran Pengajian Sosial di sekolah sistem Pendidikan Asas di Oman. The purpose of this study was to investigate Social Studies teachers' concerns and their Levels of Use in the adoption of student-centered teaching approach in Social Studies teaching and learning at the Basic Education schools in Oman

Solving Mixed Volterra - Fredholm Integral Equation (MVFIE) by Designing Neural Network

الهدف الاساسي في هذا البحث هو تقديم طريقه عدديه جديده لحل هذا النوع من المعادلات باستخدام الشبكات العصبية ANN)). حيث تم تصميم شبة عصبيه ذات تغذية اماميه(FFNN ) سريعة, هذا التصميم ذو الطبقات المتعددة والذي يحوي على طبقه واحده خفيه تحتوي على خمسة وحدات خفيه وتستخدم الدالة التحويل (log_sigmoid  ) وطبقة واحدة للإخراج, وتم تدريب الشبة باستخدام خوارزمية ليفن برك (Levenberg – Marquardt) . ولبيان دقة و كفاءة الطريقة المقدمة تم مقارنة نتائج الامثلة التوضيحية مع الحلول المضبوطة لهذه الأمثلة, و من خلال المقارنة تبين بان الطريقة ذات كفاءة و دقة عالية وذات خطاء قليل جدا.       In this paper, we focus on designing feed forward neural network (FFNN) for solving Mixed Volterra – Fredholm Integral Equations (MVFIEs) of second kind in 2–dimensions. in our method, we present a multi – layers model consisting of a hidden layer which has five hidden units (neurons) and one linear output unit. Transfer function (Log – sigmoid) and training algorithm (Levenberg – Marquardt) are used as a sigmoid activation of each unit. A comparison between the results of numerical experiment and the analytic solution of some examples has been carried out in order to justify the efficiency and the accuracy of our method.                                 &nbsp

Engineering Nanocomposite Membranes; Fabrication, Modification and Application

The engineering of novel membranes through fabrication and modification using engineered nanoscale materials (ENMs) presents tremendous opportunity within desalination and water treatment. This work presents an endeavour dedicated to investigate the design and fabrication of polymeric membranes and nanoscale materials. Also, to probe the role of nanoscale materials integration on the function of separating membranes aiming to diminish the propensity of the surface to foul.In the first part of the work, an attempt was made to research and compare the potential of versatile UF membranes structures in terms of morphology, surface characteristics and performance. The potential performance of the hand-made fabricated (UF) membranes was systematically evaluated against three organic model foulants with dissimilar origins; humic acid (HA), sodium alginate (NaAlg), and bovine serum albumin (BSA), under different initial feed concentration and pH chemistry. A diverse range of surface characteristics and morphologies have been produced as a result of varying the dope casting solution concentration, which corresponds to the wide range of commercially available UF membranes (6, 10, 35 and 100kDa). Also, a disparate fouling behaviour was observed depending on the membrane characteristics and the organic model foulant used. A one or more pore blocking mechanism were distinctly observed depending on the UF membrane cut-off used.Subsequently, the research presented the development of a novel nanocomposite membrane incorporating antimicrobial nanoparticles which have the potential to lower membrane biofouling. Antibacterial hybrid nanostructures (HNS) comprising of Ag decorated MWCNTs were successfully synthesised with the assistance of microwave irradiation. The HNS were then employed to fabricated antibacterial nanocomposite membranes via the classical phase inversion technique in order to assess their antimicrobial properties against two bacterial species; E. coli and S. aureus. The nanocomposite membranes remarkably displayed antibacterial activity (4.24 and 2.9 log kill) against the two species respectively. A higher stability under crossflow conditions was also demonstrated.Finally, for desalination applications, novel HNS comprising of a mussel-inspired PDA coated M/MO–MWCNTs, were successfully synthesised and used to fabricate TFN membranes. For comparison, four different M/MO (Al2O3, Fe2O3, TiO2 and Ag) nanoparticles (NPs) were in situ synthesised/loaded on the surface of CNTs, and the resultant HNS were further coated with a thin polymeric film of PDA. An intermediate layer of the HNS was then deposited on a PES substrate membrane, and an interfacial polymerisation (IP) process was carried out to render a polyamide (PA) thin layer above the intermediate layer. Both HNS and TFN were characterised using different characterisation tools, and the performance of nanofiltration (NF) membranes was evaluated against monovalent, divalent salts and heavy metal solutions. The fabricated TFN-NF membranes had higher performance in terms of their permeation characteristics compared to the thin film composite TFC membrane (⁓9.6-11.6 LMH), while maintaining their selectivity (≥91%) against both monovalent and divalent salts solutions, and (> 92%) against the multi-component heavy metal solution. The experimental results disclosed a high retention capability for TFC and TFN membranes along with greater potential stability/compatibility within the polymeric PA matrix. This implies that the NF membranes fabricated in this work can be employed for water reclamation purposes

Q-Series with Applications to Binomial Coefficients, Integer Partitions and Sums of Squares

In this report we shall introduce q-series and we shall discuss some of their applications to the integer partitions, the sums of squares, and the binomial coefficients. We will present the basic theory of q-series including the most famous theorems and rules governing these objects such as the q-binomial theorem and the Jacobi’s triple identity. We shall present the q-binomial coefficients which roughly speaking connect the binomial coefficients to q-series, we will give the most important results on q-binomial coefficients, and we shall provide some of our new results on the divisibility of binomial coefficients. Moreover, we shall give some well-known applications of q-series to sums of two squares and to integer partitions such as Ramanujan’s modulo 5 congruence

Education for Developing a Global Omani Citizen: Current Practices and Challenges

Oman is a developing country which reformed its educational system in 1998 in order to meet the challenges of the 21st century, especially economic challenges. Strength of national identity and developing a sense of global citizenship were among the priorities of the new educational reform. This paper is based on a review of current practices regarding global citizenship education in educational system. The purpose of this theoretical study was to explore the current provision of the aspects of global citizenship education in Omani schools. Specifically, the study attempts to identify the current practices that are implemented by Omani schools to help Omani students to develop a sense of effective global citizenship. The study indicates that Omani education is not nationally centered as it aims to develop students who have global awareness. The study shows employing different approaches to develop a sense of global citizenship, namely, a separate school subject; integrated theme in social studies education, participation in some international initiatives in global citizenship education, and celebrating the international days and decades

Preventing Childhood Obesity : Evidence, Policy and Practice

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Incorporating Citizenship Education Framework in Social Studies Teachers’ Education Programme in Sultanate of Oman

Educational system in Oman is attempting to educate Omani students to be "good" citizens in an increasingly globalized society. However, a few studies that have been conducted until now in Oman revealed a gap between the intentions of the educational policy of teaching citizenship education in the schools and the actual practices of teacher education preparation programs. Therefore, any endeavor to develop citizenship in Oman schools will not achieve its goals without taking teacher education into account both pre-service and in-service. Accordingly, the present study aims to propose a framework for developing citizenship education in the initial teacher education in Oman. This descriptive study highlighted the gap between the policy and practice in social studies teacher education. The international literature reveals that student teachers feel insufficiently prepared to develop citizenship and Omani student teachers are not exceptional. Thus, the present study proposed a framework to incorporate citizenship education in the current teachers' preparation programs. Furthermore, the study reveals the inadequate presence of the topic of citizenship in teacher education. Therefore, teachers' understanding of citizenship becomes shallow, which undoubtedly leads to superficial learning on the part of the students. Therefore, a framework was proposed to develop citizenship in teacher education. This framework consists of the rationale behind the change, the Layout of the ground for change in teacher education, the mechanisms of the change, and the areas of the change