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Pore-Scale Investigation of the Roles of Oil Types and Pore Structure in Low Salinity Waterfloogin Using Glass Micromodel

Mohammadi, Saheb | 2019

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 52226 (06)
  4. University: Sharif University of Technology
  5. Department: Chemical and Petroleum Engineering
  6. Advisor(s): Ayatollahi, Shahabodin; Mahani, Hassan
  7. Abstract:
  8. Oil composition plays an undeniable role on the low salinity water flooding (LSWF) efficiency. This property directly affects the kinetics of wettability alteration through electrostatic interactions and interfacial tension (IFT). For instance, mixing in stagnant zones through a thin water film is considered as one of the most important diffusion controlled phenomenon which is goverened by Non-Fickian solute transport model. The major two potentials controlling the solute transport in thin film are salinity gradient and electrostatic potentials, which can be affected by oil composition and surface charges. This study aims to investigate the effect of oil composition on low salinity efficiency and mixing phenomenon.Therefore, in this study we conducted a systematic series of glass micromodel experiments using different oil types with different composition which is split into two groups including model oils (non-polar oils, synthetic oil) and crude oil. The dynamic contact angle under salinity alteration (DCA-SA) was performed to confirm the micromodel results. In addition, CFD simulation using COMSOL were performed to simulate the salt transport mechanism in water film and get insights into the time-scales observed in the micromodel experiments.The results show that the presence of polar component in oil is an essential factor to achieve the low salinity effects (LSE) and increase oil recovery. The oil containing polar components (synthetic/ crude oil) would change the surface charges and expand the electrical double layer, which results in more repulsion between the solid surface and the oil phase, consequently more water wetness surface is attained. DCA-SA results clearly confirm the outcomes of micromodel tests, lowering salinity brine changes wettability towards more water wetness condition for only the oil samples that contain polar components. These results confirm that lowering the brine salinity is not sufficient for the LSE / wettability alteration to be observed and the oil polarity is an essential parameter. Increasing the polar components concentration reduces IFT and, consequently, increases the oil recovery. It should be noted that, the effect of oil polarity on in oil recovery does not obey a linear relation. Furthermore, low salinity waterflooding in the secondary injection mode has a higher potential to improve oil recovery than the tertiary mode
  9. Keywords:
  10. Enhanced Oil Recovery ; Micromodel ; Mixing Process ; Low Salinity Water Flooding ; Pore-Scale Model

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