Coupling Flow and Geochemistry for Numerical Simulation of Low Salinity/Smart Waterflooding in Carbonates

Alipour, Sina | 2019

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  1. Type of Document: M.Sc. Thesis
  2. Language: English
  3. Document No: 52299 (66)
  4. University: Sharif University of Technology, International Campus, Kish Island
  5. Department: Science and Engineering
  6. Advisor(s): Ayatollahi, Shahab; Mahani, Hassan
  7. Abstract:
  8. Due to the decrease in oil reserves in the world, increasing population and the growing demands for oil consumption in the world, increasing the oil recovery from oil reservoirs has become more important. Increasing the amount of oil production efficiency by using low salinity water/modified salinity water has been highly appreciated during the last two decades. Low-salt water is a new method, due to its advantages such as low cost, simplicity of operation and low environmental hazards. It is believed that low salinity water can alter the rock wettability from a more oil-wetting state to a more water-wetting state. In order to be able to predict the performance of low salinity water injection in core scale and reservoir scale, it is necessary to use relative permeability diagrams. In this research, a coupled flow and geo-chemistry software package was developed to numerically simulate the wettability alteration and its effect on oil production in a carbonate core. Two models were taken for changing the wettability based on SO_4 ions sticking to the surface as well as Mg,Ca and SO_4 sticking to the surface. The PHREEQC software was used in order to solve equilibrium chemical reactions at the surface of the rock and bulk. The mass transfer equations were also solved in MATLAB with finite difference method and these two software were coupled together to examine the effect of low salinity water injection. The sensitivity analysis was performed on the ion diffusion/dispersion coefficient in single-phase and two-phase flow. The results showed increase of oil recovery after injecting low salinity water – where the amount and speed of oil recovery depends on the degree of wettability alteration and dispersion coefficient. The effect of flow regime based on gravity to viscous force balance was also investigated. It was concluded that low salinity water injection had a weaker effect in reservoirs where the gravitational force was dominant
  9. Keywords:
  10. Carbonated Rock ; Wettability Alteration ; Low Salinity Water Flooding ; Numerical Simulation ; Coupling Flow and Geochemistry ; Gravity Model ; Peclet Number

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