Evaluating the Potential of CO2 Foam and CO2 Polymer Enhanced Foam for Heavy Oil Recovery in Fractured Reservoirs: Pore-Scale and Core-Scale Studies

• Author / Creator

  Telmadarreie, Ali

• Besides oil-sand reserves that should be recovered by thermal recovery methods, there are significant reserves of conventional light to heavy crude oil in the Western Canadian Sedimentary Basin (WCSB) that can be also recovered by non-thermal processes. Several carbonate reservoirs have undergone tertiary solvent/gas recovery and some of them finished with low recovery and converted to second or even third EOR process. This is almost the same for the sandstone reservoirs where the chemical flooding is the main non-thermal EOR method. Polymer loss, injectivity reduction, and inadequate sweep efficiency are the main concerns during chemical flooding. Foam and especially Polymer Enhanced Foam (PEF) can control the mobility ratio and improve the sweep efficiency in heavy oil reservoirs over chemical and gas flooding. CO2 foam (especially in reservoirs with lighter oil) and CO2 PEF (for those heavier oils) can be a good environmentally friendly choice for improving Canadian heavy oil recovery much further. The challenge is to understand how the combination of surfactant, gas, and polymer allows us to better access the untouched parts of the reservoir and increase the sweep efficiency. As of yet, there is no complete and rigorous understanding of the mechanisms during heavy oil recovery by foam, especially PEF performance in fractured porous media; therefore, this study aims to investigate direct visual observations of foam/PEF transport and heavy oil displacement phenomena in porous media. The focus of this thesis is conducting experiments to study the behavior and performance of CO2 foam/PEF for heavy oil recovery. Pore-scale analysis with the help of micromodel study and core-scale analysis by sand-pack and rock sample were performed throughout this thesis to achieve the goals. In the pore-scale analysis, a new application of CO2 foam/PEF in combination with current heavy oil recovery methods was introduced and studied. CO2 foam/PEF was used after surfactant injection in oil-wet fractured porous media and their performance was visualized with the help of a fractured micromodel. In addition, for those reservoirs where the hydrocarbon solvent injection is used as a heavy oil recovery method, this study showed that how foam/PEF could improve the solvent injection performance by increasing the heavy oil recovery and decreasing the asphaltene deposition and formation damage. Moreover, the dynamic behavior of asphaltene deposition was discussed and visualized in this thesis to show that how foam/PEF can decrease the formation damage. The core-scale performance of CO2 foam/PEF for heavy oil recovery was studied in a one-dimensional sand-pack after water flooding. Moreover, CO2 foam/PEF performance was analyzed in actual rock samples (sandstone and carbonate rocks) and effect of heterogeneity was also considered by applying artificial fracture in the rock samples. In these experiments, the injection pressure profile, oil recovery, and CO2 gas production were monitored and recorded to analyze and compare the performance of CO2 foam and CO2 PEF for both heavy oil recovery and CO2 sequestration. The results of this thesis improve our understanding of the heavy oil recovery process with the help of CO2 foam/PEF injection. Besides enhancing oil production, application of CO2 foam/PEF may reduce the amount of injected chemical into the reservoir, providing economic and environmental advantages.

• Subjects / Keywords

  • CO2 Foam EOR
  • Fractured reservoirs
  • Heavy oil

• Graduation date

  Spring 2017

• Type of Item

  Thesis

• Degree

  Doctor of Philosophy

• DOI

  https://doi.org/10.7939/R3NS0M943

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.