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Determination of Diffusion Coefficients of the Multi-components Gas-crude Oil Systems Considering Oil Swelling Effects at High Pressure High Temperature Conditions

Rostami, Keyvan | 2022

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 55214 (06)
  4. University: Sharif University of Technology
  5. Department: Chemical and Petroleum Engineering
  6. Advisor(s): Ghazanfari, Mohammad Hossein
  7. Abstract:
  8. gas injection method is one of the common methods of EOR, which has a long history. In gas injection, molecular entry gas mixing is the controlling factor of oil play. Therefore, the exact value of this coefficient becomes an important requirement for the simulation and modeling of oil reservoirs, which can only be determined by laboratory consumption methods. In this research, the pressure decay method is used as a common laboratory method to determine the penetration coefficient of methane, nitrogen and gas enriched with intermediate compounds in crude oil of one of Iran's oil reservoirs. In most of the available records in the investigation of the mentioned gas diffusion coefficient in crude oil have been done in the form of a power penetration coefficient and with the assumption of a two-component system, which is problematic due to the presence of different compounds in crude oil. In order to solve this problem, in this research, the tests of gas pressure reduction in crude oil are modeled using multi-components and using Eclipse software coupled with MATLAB programming, so that finally the diffusion of components in oil and in the gas, phase can be averaged for each test. In this research, it has been paid to determine the diffusion coefficients for the system including hydrocarbon and carbon dioxide gas and crude oil in the form of a two-dimensional tensor through the modeling of the available laboratory results. Finite difference and finite volume methods have been performed. In this part, the swelling of oil and the dependence of the diffusion coefficient on it are also mentioned. One of the topics needed in connection with gas diffusion in crude oil is the investigation of the conditions and small amount of miscibility pressure of gas in crude oil. The results of these calculations provide the possibility of investigating the mechanism of the miscibility of gases in crude oil in that it is either the evaporation mechanism or the condensation mechanism or a combination of both, which can be very good. The results of this research by presenting the diffusion coefficient of components in the two phases of oil and gas show that the experimental Sigmund relation in predicting the diffusion coefficient of components in the oil and gas phase is associated with a significant error, so it will be necessary to use this coefficient to use be oil Also, the results of modeling experiments show that the molar percentage of a component in a system reduces its diffusion coefficient in a system. will be Nitrogen gas has the lowest swelling rate among the investigated gases. For a multicomponent system, reporting a value for the diffusion coefficient is accompanied by significant error
  9. Keywords:
  10. Molecular Diffusion ; Modeling ; Laboratory ; Multiple Mixing Cell Method ; Pressure Decay Method ; Miscibility ; Multicomponent Systems ; Concentration Dependent Diffusion Coefficient

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