Maini, B. B.Husein, Maen M.Corredor Rojas, Laura Milena2019-08-142019-08-142019-08-13Corredor Rojas, L. M. (2019). The Impact of Surface Modified Nanoparticles on the Performance of Polymer Solutions for Heavy Oil Recovery (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.http://hdl.handle.net/1880/110721The use of polymer flooding as an enhanced oil recovery (EOR) method to achieve a more uniform volumetric sweep of the reservoir has increased over the past ten years. However, chemical, thermal and mechanical degradation of the polymers reduce their viscosity, which affects their performance. Nanoparticles (NPs) have been proposed as additives to make polymer flooding economical in challenging reservoirs or harsh conditions. NPs in polymer solutions (nanopolymer sols) are, nevertheless, an emerging class of materials. A more structured approach is needed to properly understand the physical and chemical interactions between the NPs and the polymer solutions. In the first stage of this study, nanopolymer sols were prepared by adding silicon oxide (SiO2), aluminium oxide (Al2O3), and titanium oxide (TiO2) NPs, and in-situ prepared iron hydroxide (Fe(OH)3) NPs to polymer solutions of partially hydrolyzed polyacrylamide (HPAM) and xanthan gum (XG). In the second stage, the surface of the NPs were modified by chemical grafting with carboxylic acids, silanes, and polyacrylamide. The modified NPs were characterized using transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and energy-dispersive X-ray spectroscopy (EDX). All prepared nanopolymer sols were evaluated to determine their effectiveness in improving heavy oil recovery by studying their rheological properties at different shear rates and NP concentrations, colloidal stability, interfacial tension (IFT), and contact angle. Finally, a selected set of nanopolymer sols were evaluated by conducting oil recovery tests in a Hele-Shaw cell and linear sand-packs. According to the observations in Hele-Shaw cell, the fingering patterns of XG and XG/1.0-2.0wt% of NPs were characterized by the formation of branched structures (at earlier growth stage) which by merging and coalescing formed stable interfaces. However, HPAM and HPAM/1.0-2.0wt% of NPs exhibited different fingering patterns with tip-splitting or suppressed tip-splitting and side-branching. Only XG polymer solutions, modified with 1.0 and 2.0 wt.% of unmodified NPs improved areal sweep efficiency between 5 - 7%. For the displacements in the linear sand-pack, the NP concentration was reduced from 1.0 wt.% to 0.2 wt.% to improve the transport of the NPs into the porous media. The incorporation of 0.2 wt.% of unmodified and modified SiO2 NPs increased the viscosity of the XG solution at all salinities, whereas the high XG adsorption onto the surface of the Fe(OH)3, Al2O3, and TiO2 NPs reduced the viscosity. Adsorption of the NPs, SDS molecules, NP-SDS complexes and NP-polymer-SDS complexes onto the oil-nanofluid interface reduced the IFT of the XG solutions. Also, the NPs changed the wettability of the glass from oil-wet to intermediate-wet. The NPs increased the cumulative oil recovery of the salt-free XG solution between 3 and 9%. At 1.0 wt% NaCl, the NPs reduced oil recovery by XG solution between 5-12%, except for Fe(OH)3 and TiO2 NPs. These NPs increased the oil recovery between 2-3% by virtue of reduced polymer adsorption caused by the alkalinity of these nanopolymer sols. Additionally, the surface properties of SiO2, TiO2 and Al2O3 NPs were improved by polymer grafting. The HPAM nanopolymer sols exhibited lower IFT and ability to alter the wettability of the glass substrate from oil-wet to intermediate-wet. The thickening behavior of the HPAM solution was improved by the addition of 0.2 and 0.4 wt % TiO2-PAM NPs at all salinities. The displacement experiments demonstrated that the addition of TiO2-PAM NPs increased the cumulative oil recovery by 2% while the addition of SiO2-PAM and Al2O3-PAM NPs reduced it between 3 and 7% at 1.0 wt.% NaCl. At higher concentration, TiO2-PAM NPs can enhance oil recovery between 5 and 7%, independent of the salinity. It was also observed that the surface modified SiO2 NPs with silanes and carboxylic acids cannot improve the performance of the HPAM solutions. To conclude, the HPAM/TiO2-PAM, the XG/Fe(OH)3 and XG/TiO2 nanopolymer sols exhibited the best performance in displacing viscous oil in the linear sand-pack tests. The original contributions to knowledge from this research are 1) development of new polymer nanohybrids which enhanced heavy oil recovery, 2) formulation of new synthesis routes for polymer nanohybrids which improved the dispersivity of the NPs into the polymer solutions and the resistance of the polymer solutions to salinity and temperature, and 3) better understanding of the mechanisms contributing to the success of nanohybrids in chemical flooding.engUniversity of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission.NanoparticlesHPAMxanthan gumpolymer floodingheavy oil recoverynanocompositesEngineering--Petroleumdoctoral thesis10.11575/PRISM/36812