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Geochemical Simulation of Acidizing Sandstone Core Samples

Khojasteh Mehr, Mohammad | 2020

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 54166 (06)
  4. University: Sharif University of Technology
  5. Department: Chemical and Petroleum Engineering
  6. Advisor(s): Bazargan, Mohammad
  7. Abstract:
  8. Acidizing is one of the widely used practices of formation damage remediation. The success of this rather expensive job depends on the precise design and operation. Though, improper execution of an acid job, not only does not improve the formation damage but also can contribute to even more damage itself. For this purpose, it is critically important to thoroughly design an acidizing job conducting extensive lab experiments and utilizing numerical tools before operation in order for a successful acidizing. Unlike, carbonate acidizing, the chemistry of sandstone acidizing is very complex and challenging because of the wide variety of minerals and aqueous species present in the system. Hence, a precise geochemical evaluation is vital. In this work, a multi-purpose reactive transport simulator with a focus on sandstone acidizing is developed. In the first chapter, the basics of sandstone acidizing are discussed. In the second chapter, a thorough literature review of the previous models is carried out and the advantages and shortcomings of the previous numerical models and also two analytical solutions (Lund and Fogler, Schechter) are explained in detail. At the end of this chapter, the necessity of developing a new geochemical model which addressed the setbacks of previous models is explained. In Chapter three, based on the proposed theory, a new model and a multi-purpose reactive transport simulator with a focus on sandstone acidizing are developed coupling OpenFOAM and Reaktoro. Among the advantages of the ReaktoFOAM simulator are solving the momentum equation, rich databases and different chemical activity models, equilibrium and kinetic calculations at a custom pressure and temperature, various CFD options, and including anisotropy and heterogeneity. Using this simulator, the LEA and the PLEA (the proposed model) methods are compared and the validity range of the LEA is discussed. Then, a sensitivity analysis of acid solution composition is conducted. Afterward, the proposed models are compared to two analytical solutions and it is showed how wrong the results of the analytical solutions can be. Eventually, for a core using Marcellus shale mineral composition, a one-dimensional LEA simulation at high Damkohler numbers is carried out. In the fourth chapter, the results of the simulations are discussed in detail and some suggestions regarding future works are listed
  9. Keywords:
  10. OpenFOAM Software ; Geochemical Modeling ; Reservoirs Acidizing ; Acidizing Treatment ; Computational Fluid Dynamics (CFD) ; Formation Damage

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