Optimization studies are an important task in reservoir engineering practices such as production optimization and EOR (Enhanced Oil Recovery) assessments. However, they are extensive studies with ...many simulations that require huge computational effort and resources. In terms of EOR, COsub.2 injection is one of the most common methods employed due to a high recovery potential and environmental benefits. To assess the feasibility of COsub.2-EOR projects, a reservoir design study must be conducted before optimization is performed. Some studies have demonstrated the advantages of employing proxy models to perform this task in terms of saving huge amounts of computer memory space and time. In this study, proxy models were developed to solve a multi-objective optimization problem using NSGA-II (Non-dominated Sorting Genetic Algorithm II) in two selected reservoir models. The study was performed for a COsub.2-WAG (Water Alternating Gas) application, where gas and water injection rates and half-cycle lengths were assessed to maximize the oil recovery and COsub.2 stored in the reservoir. One model represents a simple geological model (the Egg Model), while the other represents a complex model (the Gullfaks Model). In this study, the good performance of the proxy models generated accurate results that could be improved by increasing the amount of sampling and segmenting the behavior of the reservoir model (depending on the complexity of the reservoir model). The developed proxies have an average error of less than 2% (compared with simulation results) and are concluded to be robust based on the blind test results. It has also been found that to reach the maximum oil recovery using COsub.2-WAG, the maximum gas injection rate with the minimum water injection rate is required. However, this configuration may result in a reduction in the total COsub.2 stored in the reservoir.
In this study, a solar single/double-effect switching LiBr-Hsub.2O absorption refrigeration system was investigated to make full use of solar energy and give full play to the advantages of solar ...refrigeration systems. A corresponding thermodynamic dynamic mathematical model was developed. The operation characteristics of the system operating continuously for one week were analyzed. In order to highlight the advantages of the solar single/double-effect switching absorption refrigeration system, it was compared with other forms of solar refrigeration systems and compression refrigeration systems. The practical application potential of the single/double-effect switching LiBr-Hsub.2O absorption refrigeration system was evaluated from the perspective of economy and environmental effect. The results showed that the system could achieve the switching operation between single-effect mode and double-effect mode under weather conditions of high solar radiation intensity, and the daily cooling efficiency on such days was relatively high. After an auxiliary heater was added, the primary energy savings of the solar single/double-effect switching LiBr-Hsub.2O absorption refrigeration system were 25-52%, depending on the area of the collector and the volume of the storage tank. The solar fraction of the system was about 71.99% for continuous operation during the whole refrigeration season. However, the initial investment cost of the system equipment accounted for 89.66% of the total cost. Compared with the traditional compression refrigeration system, the initial investment cost of the solar single/double-effect switching LiBr-Hsub.2O absorption refrigeration system was higher, but it had a better environmental protection effect.
The monograph is the first study on the Polish market devoted to the functioning of safe assets in the international financial system. The concept of safe assets is more and more commonly used in ...relation to phenomena occurring in financial markets, including debt markets. However, no attempt has been made so far to comprehensively explain its complex, multi-layered nature.The authors of the monograph make a pioneering effort to explain the concept of the safe asset by indicating the attributes and functions of these financial instruments/ this category of financial instruments. In particular, two scientific perspectives are taken: demand and supply analysis. The supply analysis, which constitutes a larger part of the monograph, emphasizes the dominant role of publicly issued safe assets in relation to privately issued ones. The demand side analysis depicts the main holders of safe assets and significant changes in their motives and trends.The global public safe assets shortage and the growing demand for this category of assets pose one of the greatest challenges to the stability of the global economy, raising the question of alternative sources of meeting investors’ demand for safety. In this context, the monograph draws particular attention to the capabilities of the Economic and Monetary Union and China as potential safe assets suppliers.The book aims at graduate and PhD students of Economics who have little previous knowledge of the subject and financial market professional analysts who are wishing to move into this cutting-edge topic.
This essay explores the burdens of nightwork through the eyes of call center employees in India. India’s call centers are revealing of the ways in which work lives are reorganized to fit global ...processes. When the nights of agents are hitched directly to the days of other places, we witness not only a triumph of the global economy; we also notice certain dysfunctions of a functionally integrated world.
The development of the global economy has led to the fact that humanity has repeatedly faced complex problems that have a significant impact on the mechanism of the world economy. These problems ...fully manifested themselves in the 60-70s of the XX century and were called global. The development of the modern global economy makes adjustments to the priority of global problems. At the same time, the set of global problems is constantly changing. Old global problems acquire new content and understanding, along with the emergence of completely new global problems. The limited financial capacity of mankind to solve global problems requires political solutions and the establishment of effective international cooperation.
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