Oil recovery in porous media using emulsion flooding

• Author / Creator

  Baldygin, Aleksey

• Aiming to pursue studying enhanced oil recovery processes with an ex-situ produced emulsion as flooding agent, an improved core flooding experimental system was designed, constructed and commissioned. The developed system allows the use of not only emulsion, but also other flooding agents, including surfactants and polymers. The components of the experimental apparatus, including a biaxial core holder, a two-dimensional core holder, and effluent analysis system were re-designed to improve flow distribution, the packing process and reduce post-experimental analysis. To secure the conditions for experiments, custom software for system control and monitoring, and logging of all system parameters was developed. The limits and ways to improve the developed system were identified. An unconsolidated silica sand pack was chosen to represent the porous media on all experimental tests. The initial experimental results with emulsion flooding explored the capability of the new apparatus and confirmed the efficiency of emulsion as a flooding agent during direct emulsion flooding or water flooding followed by emulsion flooding. Oil recovery was enhanced by 15% of original oil in place in case of emulsion flooding followed by water flooding. From experimental results, it was hypothesised that emulsion moves through the sand pack with a piston-like flood front and that an alternative technique to improve efficiency of emulsion flooding can be developed. This technique should also allow to reduce amount of emulsion used per percentage of oil recovery. A flooding technique was proposed and established to improve the efficiency of emulsion flooding in reservoirs and reduce costs of flooding. The technique was named water-alternate-emulsion (WAE). Three different flooding ratios have been tested using a biaxial core holder. The experimental analysis showed that for 5:1 WAE flooding, the ultimate oil recovery could be up to 82% at 0.3 PV of total emulsion injection. The analysis of physical properties of the effluent, such as viscosity, density and surface tension, revealed that alternate flooding does not affect on physical properties of liquids involved in flooding. Effluent analysis and examination of extracted sand packs after experiment completion reported that emulsion undergoes separation inside porous media during alternative flooding and moves with a post-like flood front during continuous injection. As a results, it blocks high-permeability zones and surfactant present in emulsion interacts with in-situ liquids. Pressure measurements identified that emulsion stimulates sand packs with internal pressure rise prior to water flooding. Experimental flow visualization and pressure mapping analysis of emulsion flooding with horizontal and vertical wells was performed to provide additional understanding of internal processes. It was shown experimentally, that efficiency of emulsion flooding strongly depends on well configuration. The horizontal injection - horizontal production (HI-HP) configuration for injection and production well, based on data from effluent and image analysis, was found to be the most efficient for emulsion flooding. The flood front movement during emulsion flooding process was estimated using code developed for image analysis. Experimental data presented in this research project suggests that stable emulsion flood front and stable pressure rise guarantees enhanced oil recovery during emulsion injection. In addition, oil drops present in an emulsion were observed with a microscope and it was hypothesised that emulsion has bimodal structure. Later it was confirmed with the membrane-base particle analysers. As a results of this research study, emulsion flooding process was investigated experimentally. It was shown that emulsions can be used effectively to recover oil using different flooding techniques. Oil-in-water emulsion blocked highly permeable zones and redirecting following water flooding. Experimental results from multi-dimensional studies suggested that it is important to consider well configuration and physical parameters, such as pressure data, in a field trials. Collected results for the drop size distribution now can be considered in a future fundamental works for emulsion flooding process.

• Subjects / Keywords

  • Porous media
  • 2D core holder
  • Core holder
  • OOIP
  • Core flooding
  • Oil recovery
  • Emulsions

• Graduation date

  Spring 2015

• Type of Item

  Thesis

• Degree

  Doctor of Philosophy

• DOI

  https://doi.org/10.7939/R3ZC7S16V

• 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.