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CFD Simulation of Rotating Disk Apparatus for Obtaining Reaction Rate of HCl and Carbonate Minerals

Rabiee, Amir Hossein | 2019

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 51653 (06)
  4. University: Sharif University of Technology
  5. Department: Chemical and Petroleum Engineering
  6. Advisor(s): Shad, Saeed; Bazargan, Mohammad
  7. Abstract:
  8. Today, acidizing is one of the most important methods for stimulation and increasing the productivity of oil and gas wells. In Iran and other oil-rich countries, a large amount of money is invested every year in acidizing operations. Due to complex nature of acidizing of an oil formation, it’s very difficult to design an optimized and successful operation. Therefore, many research projects have been performed for understanding the physics of the dissolution of reservoir rock by acid and the behavior of wormholes and secondary reactions. The most important prerequisite of these researches is the perfect knowledge of acid and mineral reaction kinetics. One of the most common experiments to study the kinetics of heterogeneous reactions in the oil and gas industry, is the rotating disk experiment. In order to analyze the results of this experiment, it is necessary to have a model for it. The Levich model has been used before to analyze the results of experiments with this apparatus. This model has major weaknesses such as inability to model non-Newtonian acids, neglecting interactions between species, energy transfer and gas phase, and huge error on modeling diffusion-limited reactions. In this project, computational fluid dynamics (CFD) is used to model the rotating disk experiment. In this model hydrodynamics of flow around the disk, transfer of hydrogen ion to the disk and heterogeneous reaction of mineral and hydrogen ion is considered. The results of this model and Levich theory (in the range of validity of its assumptions) has been compared and reliability of CFD model has been verified. Moreover, the error of the Levich model for describing the properties of the diffusion boundary layer and anticipating the edge effect has been discussed. One of the major advantages of CFD simulation is its capability to upgrade in order to model some conditions and physics which Levich theory was unable to model. OpenFOAM is used to implement the CFD simulation. In order to use the CFD model to find reaction constants from rotating disk experiment, an optimization algorithm has been proposed. This algorithm is designed by observing the behavior of ”reaction rate” function and using gradient-based optimization techniques. Convergence rate of this algorithm is considerably more than other optimization algorithms in both reaction-limited and diffusion-limited regimes. Due to various challenges of carbonate acidizing, high rate of reaction of hydrochloric acid with its minerals, and the fact that most of oil and gas formations in Iran are carbonate-type formations, this thesis is concentrated on the reaction of hydrochloric acid and carbonate minerals like calcite and dolomite. Furthermore, this thesis covers the mechanical design of the rotating disk apparatus
  9. Keywords:
  10. Acidizing Treatment ; Rotating Disks ; Computational Fluid Dynamics (CFD) ; Levich Model ; Optimization ; OpenFOAM Software ; Mechanical Design ; Carbonate Minerals ; Hydrochloric Acid

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