EGU21-9127, updated on 04 Mar 2021
https://doi.org/10.5194/egusphere-egu21-9127
EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Compositional modelling of impure gas injection into saline aquifers with the MUFITS simulator

Andrey Afanasyev and Elena Vedeneeva
Andrey Afanasyev and Elena Vedeneeva
  • Moscow State University, Institute of Mechanics, Moscow, Russian Federation (afanasyev@imec.msu.ru)

We present a recent extension of the MUFITS reservoir simulator for numerical modelling of multicomponent gas injection into saline aquifers. The extension is based on the compositional module of the simulator that implements a conventional cubic equation of state (EoS) for predicting phase equilibria of reservoir fluids [1]. Now, the module is supplemented with a new library of EoS coefficients for accurate modelling of CO2, N2, CH4, H2, O2, H2S, and other hydrocarbon components solubility in NaCl brine. In general, we follow the approach proposed by Søreide and Whitson [2] for modelling aqueous solutions, which involves a different and dependent on brine salinity binary interaction coefficients for aqueous and non-aqueous phases. However, we also use several published modifications to the EoS coefficients that were originally proposed in [2] to improve prediction of the mutual solubilities.

The extension is validated against 3-D benchmark studies of pure supercritical CO2 injection into saline aquifers. Also, we consider two more complicated injection scenarios to demonstrate potential applications of the new development. First, we simulate impure CO2 injection into a saline aquifer. We show that even a small amount of air (N2 and O2) in the injected gas results in a significantly more rapid spreading of the gas plume. Second, we consider a 3-D study of CO2 injection into subsurface natural gas storage aiming at the cushion gas substitution with supercritical CO2. The mechanical dispersion in the porous medium is accounted for an accurate modelling of CO2 and CH4 mixing. We simulate the propagation of CO2 in the storage by modelling several seasons of natural gas (CH4) injection and extraction.

The authors acknowledge funding from the Russian Science Foundation under grant # 19-71-10051.

References

1. Afanasyev A.A., Vedeneeva E.A. (2020) Investigation of the efficiency of gas and water Injection in an oil reservoir. Fluid Dyn. 55(5), 621-630.

2. Søreide I., Whitson C.H. (1992) Peng-Robinson predictions for hydrocarbons, CO2, N2, and H2S with pure water and NaCl brine. Fluid Phase Equil. 77, 217-240.

How to cite: Afanasyev, A. and Vedeneeva, E.: Compositional modelling of impure gas injection into saline aquifers with the MUFITS simulator, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-9127, https://doi.org/10.5194/egusphere-egu21-9127, 2021.

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