TY - BOOK
T1 - Improved Insight into Transport Phenomena in Porous Materials at Submicrometer Resolution
AU - Gooya, Reza
PY - 2016
Y1 - 2016
N2 - Traditionally it has been challenging to investigate ƒflow properties of porous media becauseof their complex and oft‰en heterogeneous pore geometry. However, these materialsare important for oil and gas, catalysts, fuel cells, groundwater quality, CO2 storageand in medical applications. In this thesis, transport phenomena- including single phaseƒow, two phase ƒow and reactive transport, were investigated at the pore scale. Œe motivationwas to €nd cheaper, easier and faster alternatives to macroscale investigations.In the fi€rst part, single phase ƒuid flƒow models were tested on experimentally obtainedX-ray tomography 3D images of porous rocks. Œe porosity-permeability relationshipfor two dolomite rock samples showed good agreement with macroscale values.I investigated 1) the accuracy of the numerical method using both Stokes and Navier-Stokes formulations over a range of pressure gradients, 2) the heterogeneity of the sampleby applying the method on di‚fferent subvolumes and sizes of subvolumes and 3) theeff‚ect of resolution of the X-ray tomography images. Stokes and Navier-Stokes equationsprovided the same results for Re<10-2. ŒThe permeabilities of the subvolumes arevarying within an order of magnitude dependent on porosity and microstructure. ŒThechange in resolution clearly inƒfluences the calculated properties and the changes dependon the overall rock morphology and pore size distribution.In the next part, two phase flƒow was investigated at the pore scale to beŠer understanddisplacement in porous media. Surface properties of the pores are important toinclude in simulation of two phase flƒow. ThŒese properties can be parameterized in termsof contact angles between the two liquid and the solid phases. O‰en the contact angle istreated as a constant, i.e. static and not dependent on the flƒuid velocity. In fact it is notconstant. Simulations using di‚fferent formulations of the contact angle were performedas a function of ƒflow velocity and the results were compared with experimental resultsobtained by flƒow of two phases in a micrometer sized channel. ŒThe best correspondencewith the experiments was achieved using a nonlinear relationship between the contactline velocity and the ƒflow velocity. ŒThe two phase model was also directly applied on3D images of chalk, extracted from X-ray tomography data, to investigate displacementin a water-CO2 system at conditions close to supercritical CO2 injection into aquifers.A range of parameters, namely, viscosity, density and interfacial tension, at di‚fferent temperatures for water and CO2 were calculated and applied to extract the two phaseƒflow parameters for the system. Pressure of both phases, saturation rate and dynamicproperties were investigated and the results show capillary €ngering as the dominantmechanism during displacement of water by CO2.In the last part, a code was developed that couples the PHREEQC geochemical programwith the laŠice Boltzmann method to account for both flƒuid ƒflow and reactionproperties in modeling of porous materials at the pore scale. ThŒe coupled program wastested for two cases of chloride transport in a 2D channel and for a 2D ion exchanger.In this thesis, pore scale modeling was presented for several transport phenomenain porous media. ThŒeir agreement with the macroscale properties and the ability todescribe the domain in detail, prove that they can be a powerful alternative for the conventional macroscopic methods. More powerful computational resources will increasethe application of pore scale modeling.
AB - Traditionally it has been challenging to investigate ƒflow properties of porous media becauseof their complex and oft‰en heterogeneous pore geometry. However, these materialsare important for oil and gas, catalysts, fuel cells, groundwater quality, CO2 storageand in medical applications. In this thesis, transport phenomena- including single phaseƒow, two phase ƒow and reactive transport, were investigated at the pore scale. Œe motivationwas to €nd cheaper, easier and faster alternatives to macroscale investigations.In the fi€rst part, single phase ƒuid flƒow models were tested on experimentally obtainedX-ray tomography 3D images of porous rocks. Œe porosity-permeability relationshipfor two dolomite rock samples showed good agreement with macroscale values.I investigated 1) the accuracy of the numerical method using both Stokes and Navier-Stokes formulations over a range of pressure gradients, 2) the heterogeneity of the sampleby applying the method on di‚fferent subvolumes and sizes of subvolumes and 3) theeff‚ect of resolution of the X-ray tomography images. Stokes and Navier-Stokes equationsprovided the same results for Re<10-2. ŒThe permeabilities of the subvolumes arevarying within an order of magnitude dependent on porosity and microstructure. ŒThechange in resolution clearly inƒfluences the calculated properties and the changes dependon the overall rock morphology and pore size distribution.In the next part, two phase flƒow was investigated at the pore scale to beŠer understanddisplacement in porous media. Surface properties of the pores are important toinclude in simulation of two phase flƒow. ThŒese properties can be parameterized in termsof contact angles between the two liquid and the solid phases. O‰en the contact angle istreated as a constant, i.e. static and not dependent on the flƒuid velocity. In fact it is notconstant. Simulations using di‚fferent formulations of the contact angle were performedas a function of ƒflow velocity and the results were compared with experimental resultsobtained by flƒow of two phases in a micrometer sized channel. ŒThe best correspondencewith the experiments was achieved using a nonlinear relationship between the contactline velocity and the ƒflow velocity. ŒThe two phase model was also directly applied on3D images of chalk, extracted from X-ray tomography data, to investigate displacementin a water-CO2 system at conditions close to supercritical CO2 injection into aquifers.A range of parameters, namely, viscosity, density and interfacial tension, at di‚fferent temperatures for water and CO2 were calculated and applied to extract the two phaseƒflow parameters for the system. Pressure of both phases, saturation rate and dynamicproperties were investigated and the results show capillary €ngering as the dominantmechanism during displacement of water by CO2.In the last part, a code was developed that couples the PHREEQC geochemical programwith the laŠice Boltzmann method to account for both flƒuid ƒflow and reactionproperties in modeling of porous materials at the pore scale. ThŒe coupled program wastested for two cases of chloride transport in a 2D channel and for a 2D ion exchanger.In this thesis, pore scale modeling was presented for several transport phenomenain porous media. ThŒeir agreement with the macroscale properties and the ability todescribe the domain in detail, prove that they can be a powerful alternative for the conventional macroscopic methods. More powerful computational resources will increasethe application of pore scale modeling.
UR - https://rex.kb.dk/primo-explore/fulldisplay?docid=KGL01010157865&context=L&vid=NUI&search_scope=KGL&tab=default_tab&lang=da_DK
M3 - Ph.D. thesis
BT - Improved Insight into Transport Phenomena in Porous Materials at Submicrometer Resolution
PB - Department of Chemistry, Faculty of Science, University of Copenhagen
ER -