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BEGIN:VEVENT
SUMMARY:Improving the Monte Carlo algorithm for pore-network simulations o
f immiscible two-phase flow in porous media
DTSTART;VALUE=DATE-TIME:20180515T215500Z
DTEND;VALUE=DATE-TIME:20180515T215700Z
DTSTAMP;VALUE=DATE-TIME:20210918T163733Z
UID:indico-contribution-151-898@events.interpore.org
DESCRIPTION:Speakers: Santanu Sinha (Beijing Computational Science Researc
h Center)\nPore-network modeling provides a platform to study the upscalin
g problems in two-phase flow in porous media by representing the pore stru
cture with a network of links and linking the pore-scale physics to the la
rger network. However\, the bottleneck in this approach is the necessity t
o solve the pore-pressure field at each time step which makes it more and
more computationally expensive with the increase of the network size. More
over\, when interested only on the steady-state properties\, the advancing
of interfaces using the time integration provides too much information ab
out the transients. In order to improve the computational limitations inhe
rent to the network models\, we proposed a Markov Chain Monte Carlo algori
thm [1] based on the Metropolis algorithm for the pore-network simulation
of two-phase flow under macroscopic steady-state conditions. The algorithm
generates steady-state configurations of fluids based on configuration pr
obability\, and improves the computational time significantly compared to
the time stepping. The results obtained with Monte Carlo are found in agre
ement with the time stepping\, however\, it uses a rectangular sub-system
to generate trial the configurations which breaks the long range correlati
on at high saturation. A rectangular sub-system also limits the usability
of the algorithm for a irregular networks\, for example in case of the thr
ee dimensional networks reconstructed from real core samples. We will addr
ess this problem here\, by replacing the rectangular sub-system with an ir
regular sub-network of flow highways\, which can preserve the long range c
orrelations of the flow and can improve the quality of the algorithm.\n\nh
ttps://events.interpore.org/event/2/contributions/898/
LOCATION:New Orleans
URL:https://events.interpore.org/event/2/contributions/898/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Multiscale Calculation of Two-phase Flow in Digital Core Analysis
DTSTART;VALUE=DATE-TIME:20180515T201300Z
DTEND;VALUE=DATE-TIME:20180515T202800Z
DTSTAMP;VALUE=DATE-TIME:20210918T163733Z
UID:indico-contribution-151-170@events.interpore.org
DESCRIPTION:Speakers: Xiaobo Nie (Ingrain\, A Halliburton Service)\nDigita
l core analysis has become an additional tool to physical experimental ana
lysis for multiphase flow experiments. Digital core analysis is fast and c
an give more insight into the details inside a rock. In digital core analy
sis different imaging technologies with different resolutions are employed
to identify pores and textures scaled from millimeters to nanometers in a
heterogeneous rock\, such as a carbonate rock. In each resolution the fie
ld of view of 3D image volume is up to a few thousand pixel in one directi
on. Utilizing a highly efficient pore scale simulator and a powerful compu
ter\, the size of 3D rock volume that can be practically handled in a mult
iphase flow simulation is about one thousand pixels in each direction. To
compute the multiphase flow properties in a heterogeneous rock with pores
scaled from millimeters to nanometers several image resolutions have to be
combined. One approach is to compute multiphase flow properties in differ
ent scales independently and then upscale them to the whole rock sample. T
he dynamic flow exchanges in different scales are ignored. Especially the
flow path and the wettability changes provided by under-resolved finer sca
les are ignored. It is also hard to handle the effects of overlapped pores
in two images of neighboring scales in the same region in the upscaling.\
nWe developed a scale-coupled multiscale model to calculate two-phase flow
distributions for certain capillary pressure (Pc) in the porous plate exp
eriment. The two-phase distributions then can be used to calculate the rel
ative permeability (Kr) and the saturation factor (n) for capillary domina
ted flow. In the multiscale model\, a rock sample in a certain scale is ge
ometrically represented by pores\, solids and Darcy regions that have unde
r-resolved pores. Two phase flow in the resolved pore space is directly si
mulated using a lattice-Boltzmann model (LBM). The two phase flow properti
es in a Darcy region are given by a prescribed map function. The map funct
ion can be obtained in a finer scale simulation or theoretically modeling.
The map function gives the two-phase flow properties in a Darcy region ba
sed on the flow phases and pressure distributions surrounding the Darcy re
gion. In the meantime the boundary conditions on surface of a Darcy region
of LBM simulation in resolved pores depend on two phase properties in the
Darcy region. The flow distributions in pore and Darcy regions\, and the
boundary conditions for different scales dynamically change with applied c
apillary pressure. The scale coupled calculation starts from the finest sc
ale. The calculated two phase flow properties\, such as Pc\, Kr and n\, in
a finer scale serves as map functions of Darcy regions in the coarser sca
le calculation. The calculation ends in the coarsest scale\, usually the p
lug or core scale. The scale coupled multiscale model of two-phase flow ha
s been tested in different heterogeneous rock samples and two-phase flow p
roperties in different scale levels will be reported.\n\nhttps://events.in
terpore.org/event/2/contributions/170/
LOCATION:New Orleans
URL:https://events.interpore.org/event/2/contributions/170/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Studying the impact of electrode pore structure on redox flow batt
ery performance with multiphysics pore network modeling
DTSTART;VALUE=DATE-TIME:20180515T204000Z
DTEND;VALUE=DATE-TIME:20180515T205500Z
DTSTAMP;VALUE=DATE-TIME:20210918T163733Z
UID:indico-contribution-151-169@events.interpore.org
DESCRIPTION:Speakers: Jeff Thomas Gostick (University of Waterloo)\nThe re
dox flow battery is a promising energy storage technology for mitigating t
he uncertainty of renewable energy sources and bringing us a step closer t
o integrating them with the current energy grid systems. However\, they ar
e a relatively new technology that are unproven and currently too expensiv
e. Optimizing flow batteries is an active area of research since it can po
tentially reduce their cost by maximizing their performance. The optimizat
ion can be performed on multiple fronts namely new redox pairs with better
kinetics\, operating conditions such as temperature\, the macroscopic geo
metry of the flow battery\, flow configuration\, and electrode microstruct
ure. Optimizing the microstructure of flow battery electrodes is equally i
mportant but less studied compared to the other options. We provide a gene
ral modeling framework based on pore networks to study the multiphysics in
volved in a hydrogen-bromine flow battery. A numerical algorithm was devel
oped to solve the coupled systems of equations\, making this a multiphysic
s model. Because we used pore network modeling\, the simulations are relat
ively cheap in computation cost compared to direct numerical simulations a
nd therefore can be used for parametric sweeps of structural parameters in
a reasonable time. As a case study\, we use the proposed framework to inv
estigate the effects of electrode microstructural features such as porosit
y\, pore size distribution\, and fiber alignment on the overall performanc
e of the flow battery.\n\nhttps://events.interpore.org/event/2/contributio
ns/169/
LOCATION:New Orleans
URL:https://events.interpore.org/event/2/contributions/169/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Precipitation and dissolution of cement minerals in sandstone: Opp
ortunities and limitations of pore and plug scale flow analysis for reacti
ve transport modelling approaches
DTSTART;VALUE=DATE-TIME:20180515T195500Z
DTEND;VALUE=DATE-TIME:20180515T201000Z
DTSTAMP;VALUE=DATE-TIME:20210918T163733Z
UID:indico-contribution-151-168@events.interpore.org
DESCRIPTION:Speakers: Cornelius Fischer (HZDR)\nReservoir properties of sa
ndstones are controlled by precipitation and dissolution reactions at the
pore walls. Both\, the formation and dissolution of cement minerals are re
sponsible for the complex pattern formation of porosity and permeability i
n reservoir rocks. \nAt the scale of drilled core sections (plugs)\, exper
imental and analytical approaches utilize positron emission tomography (PE
T) with radiotracers (Kulenkampff et al. 2016). Resulting spatiotemporal c
oncentration distributions provide quantitative insight into fluid flow an
d diffusion parameters. The sensitivity is in the picomolar range of the u
tilized radiotracers and the spatial resolution is about 1 mm. Thus\, mech
anistically-important surface features such as etch pits or growth hillock
s and their evolution during reaction are not yet part of the direct analy
sis of the flow field.\nHere\, we present an approach based on existing in
formation about the complex crystal surface morphology and rate evolution
(Fischer& Luttge 2017). We utilize artificial materials that are produced
by 3D printing capabilities. Such an approach using PET analysis of sequen
ces of machined surfaces in flow-through experiments provides quantitative
insight into the local stability vs. temporal heterogeneity of fluid flow
close to reacting surfaces. The measured flow velocity data from PET are
implemented into reactive transport models and compared to calculations fo
cusing on small-scale surface reactivity. We discuss the resulting size an
d complexity of surface rate patterns.\n\nhttps://events.interpore.org/eve
nt/2/contributions/168/
LOCATION:New Orleans
URL:https://events.interpore.org/event/2/contributions/168/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Fluid-solid reaction in single and multiphase flows by geo-materia
l microfluidics
DTSTART;VALUE=DATE-TIME:20180515T193700Z
DTEND;VALUE=DATE-TIME:20180515T195200Z
DTSTAMP;VALUE=DATE-TIME:20210918T163733Z
UID:indico-contribution-151-172@events.interpore.org
DESCRIPTION:Speakers: Joaquin Jimenez-Martinez (EAWAG-ETHZ)\nWe are missin
g a deep understanding of the coupling of multiphase flows and fluid-solid
reactions\, including rock dissolution and mineral precipitation. To achi
eve this objective\, we designed a geo-material microfluidic cell using li
mestone from SACROC unit (Texas\, US) as substrate. For the single flow ex
periment\, supercritical (sc) CO$_2$ dissolved in brine was flowed through
a controlled etched geometry. In the same geometry\, CO$_2$-saturated bri
ne and scCO$_2$ were simultaneously injected for the multiphase flow exper
iment. Dissolution and precipitation rates for single and multiphase flows
were deduced from high-precision 3D measurements\, and changes in permeab
ility from pressure measurements. We also simulated the flow through the p
ore space to quantify changes in flow dynamics due changes in geometry. We
showed the coupling of single and multiphase flow and fluid-solid reactio
ns\, demonstrating the impact of multiphase flows on the latter.\n\nhttps:
//events.interpore.org/event/2/contributions/172/
LOCATION:New Orleans
URL:https://events.interpore.org/event/2/contributions/172/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Multi-scale modeling of coupled diffusion-electrochemical reaction
for porous micro-electrodes incorporating enzymatic catalysis
DTSTART;VALUE=DATE-TIME:20180515T211600Z
DTEND;VALUE=DATE-TIME:20180515T213100Z
DTSTAMP;VALUE=DATE-TIME:20210918T163733Z
UID:indico-contribution-151-174@events.interpore.org
DESCRIPTION:Speakers: Didier Lasseux (I2M Bordeaux)\nPorous electrodes wit
h high specific surface area have been efficiently applied to design minia
turized electro-devices such as bio-batteries\, bio-captors\, etc. Such el
ectrodes may provide much higher electrical current than classical flat el
ectrodes of the same macroscopic size [1]. In a previous work [4]\, a mult
i-scale model of diffusion and electrochemical reaction in porous electrod
es has been developed for a simple oxygen reduction reaction so that oxyge
n is reduced to hydrogen peroxide by directly consuming electrons at the c
athode. In order to improve the efficiency of such devices\, redox reactio
ns may be catalyzed by enzymes which are immobilized within a polymer laye
r in the vicinity of the solid surface [2]. In the present work\, we devel
op a multi-scale model of coupled transport and electrochemical reaction i
n porous electrodes operating in the enzymatic Direct Electron Transfer re
gime where complex reactions induced by the enzymes together with their ma
ss balance are taken into account. \n\nAt the microscopic pore-scale\, an
electrochemical model for complex redox enzymatic reactions at the solid-f
luid interface is developed\, considering the oxygen reduction reaction wh
ich is catalyzed by the bilirubin oxidase enzyme (BOD) at the cathode. In
this scenario\, the Butler-Volmer equation is used to relate the potential
and reaction rates with the current. This electrochemical model is furthe
r coupled with the mass transfer of oxygen governed by Fick's law and the
mass balance of enzymes to form the microscopic coupled model in transient
regime. By making use of the volume averaging method [3]\, the above ment
ioned microscopic problem is upscaled to obtain a macroscopic model. This
model is characterized by a macroscopic coupled diffusion-reaction equatio
n in the porous electrode involving an effective diffusion coefficient tha
t can be computed from the solution of an intrinsic closure problem. Using
a model pore geometry\, 3D direct numerical simulations of the microscopi
c model are carried out and compared to 1D numerical simulations of the ma
cro-model. Excellent agreement between the oxygen concentration profiles w
ithin the electrodes obtained from the two models is observed while a spee
d-up of about 21600 is achieved with the 1D macro-model illustrating the c
apability of the multi-scale approach. Such a model is capable of providin
g an accurate estimation of the electrical current density with respect to
the pore-space architecture providing a useful tool for electrode microst
ructural optimization. A successful comparison between the model and exper
iments is also reported. \n\nKeywords: Porous electrode\, Diffusion\, Reac
tion\, Volume averaging\, Enzyme.\n\nhttps://events.interpore.org/event/2/
contributions/174/
LOCATION:New Orleans
URL:https://events.interpore.org/event/2/contributions/174/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Tracer Transport Characterization of Interactions Between Resident
and Infiltrating Water During Drainage-Imbibition Cycles
DTSTART;VALUE=DATE-TIME:20180515T220100Z
DTEND;VALUE=DATE-TIME:20180515T220300Z
DTSTAMP;VALUE=DATE-TIME:20210918T163733Z
UID:indico-contribution-151-730@events.interpore.org
DESCRIPTION:Speakers: Pei Li ()\nWe quantify interactions between resident
and infiltrating water coupled with tracer transport during water-air\, d
rainage-imbibition cycles. Using a 2D Lattice Boltzmann method (LBM)\, we
investigate immiscible-miscible and tracer transport processes in an heter
ogeneous pore structure with various boundary conditions. The simulations
clearly show three types of interactions between resident and infiltrating
water: (1) flushing of resident water\; (2) mixing between resident and i
nfiltrating water\; and (3) bypassing of resident water. Some of the (init
ial) resident water\, containing tracer\, remains in the pore space\, espe
cially larger pores\, even after two drainage-imbibition cycles. We analyz
ed the sensitivity of these three types of interactions to flux on the bou
ndary\, contact angle\, body force and porosity. The results on ‘old’
and ‘new’ water saturation\, pockets number and the tracer concentrati
on in the outflow demonstrate that the boundary flux and the porosity are
critical factors affecting these interactions. Thus\, the initial saturat
ion and distribution of resident water are not the only factors affecting
interactions between resident and infiltrating water. Although it is diffi
cult to directly link such pore-scale simulations to macroscales\, the res
ults show a certain correlation to field-scale phenomena: similar to field
measurements\, we find that infiltrating water represents the majority of
water reaching the domain outlet at short times with higher input flux\,
while a mixture of resident and infiltrating water then elutes over longer
times with lower input flux. Our simulations also show intrinsically how
resident water can remain in the domain over long times (months and even y
ears)\, as found at the field scale\, and demonstrate that LBM is capable
of simulating transport phenomena in partially saturated porous media.\n\n
https://events.interpore.org/event/2/contributions/730/
LOCATION:New Orleans
URL:https://events.interpore.org/event/2/contributions/730/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Direct pore-scale modeling of thermal dispersion in granular porou
s media: the effect of medium heterogeneity
DTSTART;VALUE=DATE-TIME:20180515T205800Z
DTEND;VALUE=DATE-TIME:20180515T211300Z
DTSTAMP;VALUE=DATE-TIME:20210918T163733Z
UID:indico-contribution-151-171@events.interpore.org
DESCRIPTION:Speakers: Saied Afshari (University of Calgary)\nThe thermal i
nteractions of fluid-solid regions occurring at pore-level during non-isot
hermal flow in porous media is usually characterized by the thermal disper
sion coefficient at the macroscale. Thermal dispersion coefficient represe
nts the combined effect of thermal diffusion and mechanical convection on
the dynamics of heat transport in a porous medium. Thermal diffusion is th
e transport of energy due to the temperature gradient whereas mechanical c
onvection arises from the variations of the velocity field inside the medi
um. These variations in the velocity magnitude and direction are the direc
t result of the heterogeneous nature of pore space as well as the interact
ion of fluid and solid regions. In this study\, direct pore-level numerica
l simulations are employed to model flow and heat transport in digital gra
nular porous media with different levels of heterogeneity. The granular po
rous media are generated based on the swelling sphere reconstruction algor
ithm with variable grain diameters taken from a particle size distribution
. The heterogeneity of these media is characterized by the standard deviat
ion of the distribution. We solve the Navier-Stokes and heat convection-di
ffusion equations through a fully implicit scheme to obtain the spatiotemp
oral profiles of velocity and temperature at pore scale\, respectively. Th
e pore-scale temperature profiles are then used to compute the macroscopic
thermal dispersion coefficient at different values of flow velocity\, sol
id-fluid thermal conductivity ratio\, and medium heterogeneity. Finally\,
the calculated dispersion coefficients are correlated against the relevant
dimensionless numbers that describe the characteristics of the fluid-poro
us media system. The analysis and interpretation of these results provide
several new insights on the role of medium heterogeneity in thermal disper
sion during flow in granular porous media.\n\nhttps://events.interpore.org
/event/2/contributions/171/
LOCATION:New Orleans
URL:https://events.interpore.org/event/2/contributions/171/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Stable and efficient time integration at low capillary numbers of
a dynamic pore network model for immiscible two-phase flow in porous media
DTSTART;VALUE=DATE-TIME:20180515T215200Z
DTEND;VALUE=DATE-TIME:20180515T215400Z
DTSTAMP;VALUE=DATE-TIME:20210918T163733Z
UID:indico-contribution-151-897@events.interpore.org
DESCRIPTION:Speakers: Magnus Aa. Gjennestad (Norwegian University of Scien
ce and Technology)\nNumerical instabilities at low capillary numbers is a
problem that has been reported for different types of pore network models
[2]\, and first to address the issue was Koplik and Lasseter [4]. As most
practical applications are in this regime\, such as water flow in fuel cel
l gas diffusion layers and flow of carbon dioxide some distance away from
the injection well in carbon dioxide sequestration\, it is important to ad
dress such stability issues in a rigorous manner.\n\nThe pore network mode
l we consider is of the type first presented by Aker et al. [1]. Since fir
st introduced\, it has been improved upon several times. With Aker-type po
re network models\, the numerical instabilities manifest themselves as non
physical oscillations of the fluid interface positions. Some attempts to
prevent these oscillations by introducing changes to the model have been m
ade. For invasion of water in a fuel cell gas diffusion layer\, Medici and
Allen [5] used a scheme that allowed forward flow of water only. The pric
e that is paid when using this approach is that interface movement is seve
rely restricted and some dynamic effects\, such as the retraction of the i
nvasion front after a Haines jump\, can no longer be resolved. Another lim
itation is that this scheme can only be used in transient invasion cases a
nd studies of steady-state flow [6] cannot be performed.\n\nAs the instabi
lities are numerical\, rigorous attempts deal with them should focus on th
e numerical methods\, rather than introduce changes to the model. Such an
approach was pursued by Joekar-Niasar et al. [3]\, however\, for a differe
nt type of network model that the one considered here. They used a lineari
zed semi-implicit method to achieve stabilization.\n\nWe present numerical
procedures that can be used to simulate two-phase flow in porous media at
low capillary numbers in a stable manner using the Aker-type pore network
models. Thus\, we solve the previously observed stability problems withou
t resorting to changes in the model that restrict interface movement or pr
event the study of steady-state flow. We will consider three methods\, two
explicit methods and a new semi-implicit method. The explicit methods are
stabilized by a new time step criterion. Further\, we present a thorough
verification of the all three methods\, confirming that they solve the mod
el equations and exhibit correct convergence behavior\, and we compare the
ir performance.\n\nhttps://events.interpore.org/event/2/contributions/897/
LOCATION:New Orleans
URL:https://events.interpore.org/event/2/contributions/897/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Investigation of mineralogical heterogeneity in chemical dissoluti
on of sandstones
DTSTART;VALUE=DATE-TIME:20180515T215800Z
DTEND;VALUE=DATE-TIME:20180515T220000Z
DTSTAMP;VALUE=DATE-TIME:20210918T163733Z
UID:indico-contribution-151-731@events.interpore.org
DESCRIPTION:Speakers: Min Liu ()\nReactive transport in sandstones is of i
mportance for applications including acid stimulation methods\, contaminan
t remediation and carbon dioxide sequestration. Natural sandstones consist
of various minerals. These different minerals can lead to large discrepan
cy in predicting petrophysical properties. Simulation results of multi-min
eral and single mineral reactions are compared to illustrate the impact of
mineralogical heterogeneity on reactive transport behaviors in sandstones
.A reactive transport model based on lattice Boltzmann and finite volume m
ethod is applied to simulate dissolution in sandstones. The model includes
the solute transport\, chemical dissolutions and solid update. It is vali
dated by comparing against reaction simulations in fracture geometry and d
ynamic imaging experimental observations. The imaging technique QEMSCAN SE
M-EDS is used to acquire 3D mineral mapping of sandstones. 3D X-ray micro-
CT tomogram is then segmented based on the correlation between X-ray atten
uation of tomogram. Multi-mineral reaction simulations are performed on im
ages containing various minerals. The results are then compared with the p
rediction of single mineral dissolution.Simulation results of multi-minera
l and single mineral reactions are compared in different flow regimes. Per
meability variations are studied in different flow regimes. Average reacti
on rates\, surface area and pore size distributions are also presented. It
is found that the existence of various minerals results in more heterogen
eous dissolution in sandstones due to the different reaction rates. Minera
logical heterogeneity leads to significant errors of permeability predicti
on when single mineral is assumed in sandstones. This error is related wit
h flow regimes. In low Péclet regimes\, the predicted permeability is ove
restimated. However\, in regimes with high Péclet\, it is lower than the
results in multi-mineral reaction. Compared with high Péclet regimes\, th
e errors are more significant in low Péclet regimes. The average dissolut
ion rates in multi-mineral simulation are higher than the prediction in si
ngle-mineral reaction. This is due to the uneven dissolution in multi-mine
ral reaction. Large discrepancy is also observed in pore size distribution
s. The pore sizes are more uniform in multi-mineral dissolution during the
dissolution. This study improves the understanding of reactive flow and i
llustrates the strong dependence of mineralogical heterogeneity on reactio
n rates in reactive transport.\n\nhttps://events.interpore.org/event/2/con
tributions/731/
LOCATION:New Orleans
URL:https://events.interpore.org/event/2/contributions/731/
END:VEVENT
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