Mohammad Hossein Golestan has submitted the following academic thesis as a part of the doctoral work at the Norwegian University of Science and Technology (NTNU), Department of Geosciences:
«Pore-scale investigations of fluid flow and interfacial mass transfer»
For electronic version of the thesis, please contact: anne.lise.brekken@ntnu.no
The Faculty has appointed the following Assessment Committee to assess the thesis:
· Professor Lesley Anne James, Memorial University of Newfoundland, Canada (1. Opponent)
· Senior Researcher Johan Olav Helland, NORCE(2. Opponent)
· Associate Professor Antje van der Net, NTNU
Associate Professor Antje van der Net, Department of Geosciences, NTNU, has been appointed Administrator of the Committee.
The Committee recommends that the thesis is worthy of being publicly defended for the PhD degree.
The doctoral work has been carried out at the Department of Geosciences.
The trial lecture will take place on 7th February at 10:15 in room 265, Sentralbygg 1, Gløshaugen on the following prescribed subject:
“Implications of thermodynamics on multicomponent, multiphase mass transfer in porous media”
The public defence of the thesis takes place on 7th February at 13:15 in room 265, Sentralbygg 1, Gløshaugen.
Professor Carl Fredrik Berg, Department of Geosciences has been the candidate’s main supervisor. Professor emeritus Ole Torsæter, Department of Geosciences, has been the candidate’s co-supervisor.
Abstract:
In this thesis, we investigated fluid flow in porous media from a pore-scale perspective and derived continuum-scale properties. This study conducts statistical analysis of single-phase flow and implements experimental and simulation methods to examine the effects of interfacial mass transfer on the pore scale. Interfacial mass transfer refers to the movement of mass between two phases that share a boundary or interface. This can occur between a liquid and a gas or two immiscible liquids. For example, understanding the dynamics of interfacial mass transfer is crucial in processes such as CO2 dissolution in brine during storage of CO2 in the subsurface, where it is essential for predicting the long-term storage capacity of subsurface porous structures. In one part of this study, we attempt to enhance our understanding of the dissolution-trapping mechanism of supercritical CO2 (scCO2) in saline aquifers during the process of CO2 sequestration by conducting interfacial mass transfer computational fluid dynamics simulations. Another part of this thesis considers oil remobilization during lowsalinity water flooding. Osmosis and emulsification are two potential reasons for explaining the remobilization. The contributions of these two phenomena are not well studied at the pore scale. This thesis, therefore, presents microfluidic experiments to investigate the movement of oil constrained between invading low-salinity brine and residual high-salinity brine. Overarching mass transfer on the pore scale is the pore structure itself. To investigate the connection between pore structure and continuum scale flow properties, we developed an alternative procedure for estimating micro-structural attributes via the Bayesian network theory.
Traditional investigation of fluid flow in porous media often relies on a continuum approach, which, however, has limitations as it overlooks microscale intricacies. In this thesis, we have conducted a detailed analysis of the dissolution trapping dynamics that occur during the injection of scCO2 into porous media saturated with brine. To model the combined behavior of two-phase fluid flow and interfacial mass transfer at the pore scale, we have utilized simulations based on the volume-of-fluid (VOF) method. The objective of these simulations is to accurately represent the dynamic dissolution of scCO2 in a brine aquifer.
Another example of interfacial mass transfer occurs during low salinity water injection for enhanced oil recovery, in which the salinity of the injected water differs from the water already present in the oil reservoir. This difference means that when an oil layer is present between the low-salinity water and the high-salinity water in the reservoir, the water passes through the oil layer and reaches the high-salinity water, causing it to expand. This water expansion can lead to oil remobilization during low-salinity water flooding. In this thesis, we have conducted a range of microfluidic experiments to investigate the mass transfer due to osmosis and emulsification. In these experiments, we observe the transfer of water from the low-salinity to the high-salinity brine, leading to an increase in the volume of the high-salinity brine. This volume change induces movement of the oil constrained between the two brines of different salinity, possibly leading to enhanced oil production. We have also modeled this mass transfer using the lattice-Boltzmann method.
Pore-scale modeling involves diverse methodologies and approaches for simulating fluid flow, transport, and reactions within microscopic porous media. While the current literature predominantly focuses on applying simulation techniques or comparing their effectiveness, in this thesis, we developed an intuition of providing an alternative procedure for estimating micro-structural attributes via the Bayesian network theory. This theory is applied to flow properties but could be extended to other transport mechanisms, including mass transfer.