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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Simulation study of polymer microgel conformance treatments

Abdulbaki, Mazen Ramzi 06 November 2012 (has links)
Significant quantities of hydrocarbon are bypassed during conventional waterfloods. This is the direct result of fluid channeling through high permeability zones within the reservoir. Conformance control offers a mean of increasing vertical and areal sweep efficiency, thus decreasing the amount of hydrocarbon bypassed. This, in turn, results in increased hydrocarbon production, decreased water cut, and field life extension. This thesis focuses on the use of polymer microgels as a relatively novel conformance control agent. Polymer-microgel-enhanced waterflooding tackles fluid channeling by “plugging” high permeability channels, or thief zones, and diverting trailing flooding fluid to adjacent poorly swept areas of the reservoir. The first major objective of this thesis was to provide an extensive literature survey on polymer microgel technology, which can serve as the go-to reference on this topic. Colloidal Dispersion Gels (CDGs), Preformed Particle Gels (PPGs), temperature-sensitive polymer microgels (Bright Water), and pH-sensitive polymer microgels are all discussed in detail, and an attempt is made to highlight the potential mechanisms by which they plug thief zones and improve oil recovery. This thesis then outlines the results of simulating numerous polymer microgel floods, ranging from experimental cases to field cases. Specifically, Colloidal Dispersion Gels (CDGs) were chosen for the simulations undergone. All simulations were run using UTGEL, a newly developed in-house simulator designed exclusively for the simulation of polymer, gel, and microgel floods. The simulations performed provide insight on the polymer microgel flooding process, and also served as a means of validating UTGEL’s polymer microgel (CDG) models. The development of the UTGEL simulator was important as it enables the optimization of polymer microgel floods for maximized hydrocarbon recovery efficiency. The results of a simulation study, using a synthetic field case, are also outlined. This sensitivity study provides additional insight on optimal operational conditions for polymer microgel technology. More specifically, this study aimed to investigate the effectiveness of microgel flooding treatments in layered reservoirs of varying permeability contrasts, vertical-to-horizontal permeability ratios, and under a variety of different injection concentrations. / text
2

Marine biogenic polysaccharides as a potential source of aerosol in the high Arctic : Towards a link between marine biology and cloud formation

Gao, Qiuju January 2012 (has links)
Primary marine aerosol particles containing biogenic polymer microgels play a potential role for cloud formation in the pristine high Arctic summer. One of the major sources of the polymer gels in Arctic aerosol was suggested to be the surface water and more specifically, the surface microlayer (SML) of the open leads within the perennial sea ice as a result of bubble bursting at the air-sea interface.  Phytoplankton and/or ice algae are believed to be the main origins of the polymer gels. In this thesis, we examine the chemical composition of biogenic polymers, with focus on polysaccharides, in seawater and airborne aerosol particles collected during the Arctic Summer Cloud Ocean Study (ASCOS) in the summer of 2008. The main results and findings include: A novel method using liquid chromatography coupling with tandem mass spectrometry was developed and applied for identification and quantification of polysaccharides. The enrichment of polysaccharides in the SML was shown to be a common feature of the Arctic open leads. Rising bubbles and surface coagulation of polymers are the likely mechanism for the accumulation of polysaccharides at the SML. The size dependencies of airborne polysaccharides on the travel-time since the last contact with the open sea are indicative of a submicron microgel source within the pack ice.  The similarity of polysaccharides composition observed between the ambient aerosol particles and those generated by in situ bubbling experiments confines the microgel source to the open leads. The demonstrated occurrence of polysaccharides in surface sea waters and in air, with surface-active and hygroscopic properties, has shown their potential to serve as cloud condensation nuclei and subsequently promote cloud-drop activation in the pristine high Arctic. Presumably this possibility may renew interest in the complex but fascinating interactions between marine biology, aerosol, clouds and climate. / At the time of doctoral defence, the following paper was unpublished and had a status as follows: Paper 4: Manuscript

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