Experimental Testing of New Generation Chemicals and Conventional Surfactants as Additives to Steam Injection

  • Author / Creator
    Bruns, Fritjof
  • With the decrease in nonrenewable energy sources, heavy oil and bitumen recovery gains more attention due to their huge potential. The recovery of heavy oil or bitumen requires viscosity reduction where steam is commonly injected to mobilize and displace viscous oil. This application, however, has several disadvantages including high water demand, big energy consumption for steam generation, and carbon footprint. To minimize these drawbacks and improve process efficiency, chemicals can be added to the steam. Chemical additives, specifically surfactants and caustic, to steam applications was initially considered in the 80’s (Castanier and Brigham, 1991), but later lost attention due to high cost and difficulties in finding thermally stable agents. As steam applications become more fashionable and new techniques such as Steam Assisted Gravity Drainage (SAGD) has been developed, research on chemical additives has regained attention. This study dealt with an experimental investigation of different chemicals to high temperature processes and outlines advantages and disadvantages of the candidates (cost, increase in oil recovery, etc.). The chemical database created in this project can be categorized into solvents (hydrocarbon and water-soluble solvents), surfactants (anionic and non-ionic surfactants), caustic injection (high pH solution), ionic liquids, and nanofluids. Thermal stability of the additives is one of the major challenges. Commercially available chemicals were tested on thermal stability using Thermogravimetric Analysis (TGA) where the decomposition of the chemical is measured by mass over constant temperature increase (up to 400\degree C). Non-ionic surfactants exhibited good thermal stability compared to anionic surfactants. Selected chemicals were then assessed on steam-to-oil (SOR) ratio by developing steam injection experiments on sandpacks. The changes in the SOR were quantified by measuring the increase in oil recovery. The observed performance improvements were compared with the commercial prices and the equalized injected concentration of the chemicals to conclude the screening of the chemical dataset. It was shown that heptane and biodiesel were the most efficient chemicals in terms of SOR and price. Assumptions were made related to the flow parameters effected by the chemicals. To further investigate the mechanics of the recovery improvements process with chemicals, a visual Hele-Shaw model was developed. These experiments confirmed some key theories drawn by the sandpack experiments such as the emulsification and interfacial tension (IFT) reduction by surfactants, asphaltene precipitation and the viscosity decrease by hydrocarbon solvents, wettability alteration by ionic liquids etc. Lastly, further screening procedures were emphasized for future research to optimize the implementation factors (such as concentration or injection strategies) as well as for quantification of improved flow parameters (such as IFT reduction or emulsification).

  • Subjects / Keywords
  • Graduation date
    Spring 2019
  • Type of Item
  • Degree
    Master of Science
  • DOI
  • License
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