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Pore Scale Modeling and Upscaling of Non-Aqueous Phase Liquid Dissolution, Flow and Distribution in Heterogeneous Porous Media

Khasi, Saeed | 2018

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 51143 (06)
  4. University: Sharif University of Technology
  5. Department: Chemical and Petroleum Engineering
  6. Advisor(s): Ghazanfari, Mohammad Hossein
  7. Abstract:
  8. In this work, flow transport, distribution, and dissolution of non-aqueous phase liquids (NAPLs) in heterogeneous porous media were modeled by focusing on the dissolution process in pore-level and field scale. First, by adopting advection-diffusion and mass transfer equations, dissolution process and NAPL distribution were investigated in a heterogeneous porous media using pore network modeling. The 2-D developed model was based on observations of micromodel tests. The pore scale simulator which adopted by this work was improved in some aspects in comparison to previous models in the literatures. First, in the phase displacement, by considering more realistic geometries for pore structure and using capillary-desaturation curves (CDCs), the evaluation of the residual fluid distribution was improved which confirmed by experimental data validation. A physical-experimental model which called the gray-box approach was developed for the modeling of the mass transfer. By considering inherent heterogeneities in micromodels, the probability distribution function for pore sizes was determined. Using simulation results, the mass transfer rate coefficient was evaluated at different injection rates and fluid saturation. Comparison these results with those of mechanistic or empirical models revealed a much better matching with experimental data in the gray-box model. The relaxation of some simplifying assumptions in the mechanistic models such as considering non-uniform velocity profiles or changing boundary conditions could slightly improve the matching, especially at low flow rates. The mass transfer rate coefficients obtained from different mass transfer models were used in upscaling and large-scale simulation. The macroscopic simulations showed that the shrinkage of NAPL was greatly affected by adopting different approaches of mass transfer modeling. Based on these results, a methodology was proposed for modeling of flow, distribution, and dissolution of NAPLs in aquifers to design and predict the performance of remediation methods
  9. Keywords:
  10. Upscaling ; Mass Transfer ; Nonaqueous Phase Liquid (NAPL) ; Heterogeneous Porous Media ; Pore Network Model

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