Christina Karapataki

The emergence of large-scale hydrocarbon production from shale reservoirs has revolutionized the oil and gas sector, and hydraulic fracturing has been the key enabler of this advancement. As a result, the need for water treatment has increased significantly and became a major cost driver for producers. What to do with the flowback water in light of scarce disposal facilities and substantial handling costs is a major impediment to the development of the natural gas resource, particularly in the… Show more

The emergence of large-scale hydrocarbon production from shale reservoirs has revolutionized the oil and gas sector, and hydraulic fracturing has been the key enabler of this advancement. As a result, the need for water treatment has increased significantly and became a major cost driver for producers. What to do with the flowback water in light of scarce disposal facilities and substantial handling costs is a major impediment to the development of the natural gas resource, particularly in the Marcellus shale. This thesis explores the technical, economic and regulatory issues associated with water treatment in the shale plays and identifies best practice water management pathways based upon the Marcellus shale characteristics. The key factors that affect the choice of water treatment options and infrastructure investments are identified and investigated in detail. These include, among others, proximity to disposal facilities, transportation costs, potential for wastewater reuse and make-up water requirements. The study is supplemented by an analysis of the flowback water geochemistry and an examination of the chemical components, like barium and strontium hardness ions, that can restrict the potential of flowback water reuse. Important insights that will help inform the policy debate on how to best address both the environmental and operational water issues associated with hydraulic fracturing in the Marcellus region are derived through this study. Better reporting and monitoring of wastewater volumes is one of the main recommendations of this thesis. A wastewater management and reporting system that focuses on the optimization of water reuse among producers and facilitates information sharing could offer significant efficiencies in terms of reducing costs and minimizing negative environmental impacts. Show less

For the past several years, Cyprus has been facing an unprecedented water crisis. Four options that have been considered to help resolve the problem of drought in Cyprus include imposing effective water use restrictions, implementing water-demand reduction programs, optimizing water supply systems, and developing sustainable alternative water source strategies. An important aspect of these initiatives is the accurate forecasting of short-term water demands, and in particular, peak water… Show more

For the past several years, Cyprus has been facing an unprecedented water crisis. Four options that have been considered to help resolve the problem of drought in Cyprus include imposing effective water use restrictions, implementing water-demand reduction programs, optimizing water supply systems, and developing sustainable alternative water source strategies. An important aspect of these initiatives is the accurate forecasting of short-term water demands, and in particular, peak water demands. This study compared multiple linear regression and three types of multilayer perceptron artificial neural networks (each of which used a different type of learning algorithm) as methods for peak weekly water-demand forecast modeling. The analysis was performed on 6 years of peak weekly water-demand data and meteorological variables (maximum weekly temperature and total weekly rainfall) for two different regions (Athalassa and Public Garden) in the city of Nicosia, Cyprus. 20 multiple linear regression models, 20 Levenberg-Marquardt artificial neural network (ANN) models, 20 resilient back-propagation ANN models, and 20 conjugate gradient Powell-Beale ANN models were developed, and their relative performance was compared. For both the Athalassa and Public Garden regions in Nicosia, the Levenberg-Marquardt ANN method was found to provide a more accurate prediction of peak weekly water demand than the other two types of ANNs and multiple linear regression. It was also found that the peak weekly water demand in Nicosia is better correlated with the rainfall occurrence rather than the amount of rainfall itself.
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