HS8.1.2

EDI
Advances in coupled fluid dynamics, heat and solute transport, and (bio-)geochemical reactions in subsurface fractured and porous media: experiments, models and field observations

Dissolution, precipitation, and chemical reactions between infiltrating fluid and rock matrix alter the composition and structure of the rock, either creating or destroying flow paths. Strong, nonlinear couplings between the chemical reactions at mineral surfaces and fluid motion in the pores often leads to the formation of intricate patterns: networks of caves and sinkholes in karst area, wormholes induced by the acidization of petroleum wells, porous channels created during the ascent of magma through peridotite rocks. Dissolution and precipitation processes are also relevant in many industrial applications: dissolution of carbonate rocks by CO2-saturated water can reduce the efficiency of CO2 sequestration, mineral scaling reduces the effectiveness of heat extraction from thermal reservoirs, acid rain degrades carbonate-stone monuments and building materials.

With the advent of modern experimental techniques, these processes can now be studied at the microscale, with direct visualization of the evolving pore geometry. On the other hand, the increase of computational power and algorithmic improvements now make it possible to simulate laboratory-scale flows while still resolving the flow and transport processes at the pore-scale.

We invite contributions that seek a deeper understanding of reactive flow processes through interdisciplinary work combining experiments or field observations with theoretical or computational modeling. We seek submissions covering a wide range of spatial and temporal scales: from table-top experiments and pore-scale numerical models to the hydrological and geomorphological modelling at the field scale. We also invite contributions from related fields, including the processes involving coupling of the flow with phase transitions (evaporation, sublimation, melting and solidification).

Co-organized by ERE4/GM3/GMPV6
Convener: Linda Luquot | Co-conveners: Yves Meheust, Piotr Szymczak, Vittorio Di Federico, Sylvain Courrech du Pont, Oshri Borgman, Florian Doster
Presentations
| Thu, 26 May, 08:30–11:40 (CEST)
 
Room 2.31

Presentations: Thu, 26 May | Room 2.31

08:30–08:35
08:35–08:42
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EGU22-825
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Virtual presentation
Thermal convection in a three-layered air-heat-generating porous-air system with internal heat source depending on solid volume fraction
(withdrawn)
Ekaterina Kolchanova and Nikolay Kolchanov
08:42–08:49
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EGU22-983
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Virtual presentation
Experimental study on thermal dependence of the permeability of heat-generating porous medium
(withdrawn)
Aleksandr Sidorov
08:49–08:56
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EGU22-988
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Virtual presentation
Long-wave and short-wave instabilities in a two-layered air-porous system with vertical throughflow and internal heat source depending on solid volume fraction
(withdrawn)
Rafil Sagitov
08:56–09:03
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EGU22-2112
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ECS
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On-site presentation
Pejman Abolhosseini, Thomas Robert, Richard Martel, and Satinder Kaur Brar

Hydrocarbon contamination is among the most frequent sources of soil and water environmental impacts. Many remediation methods have been implemented to clean up the contaminated environment so far. In-Situ Chemical Oxidation has attracted attention as it has shown efficiency in contaminants removal and cost-effectivity. In addition, soil washing by surfactant foam has been recently proven as a promising method. The combination of these two methods can take the advantage of oxidation while eliminating the challenges regarding the poor distribution of treatment fluid in a heterogeneous porous media. The ultimate goal of this study is to use surfactant foam for delivering oxidant (persulfate) through diesel-contaminated soil in permafrost. However, the interaction between the surfactant and the oxidant needs to be studied first. A better understanding of the impact of surfactants and oxidants on each other can lead to an optimized process. At the first stage of this study, different concentrations of surfactant solutions (sodium dodecyl sulfate: cocamidopropyl betaine in a mass ratio of 1:1) were mixed with a constant persulfate concentration activated with alkali, in absence of hydrocarbon. The preliminary results showed that the initial concentration of the oxidant has no significant effect on its decomposition rate. Also, as the concentration of surfactant was increased above the Critical Micellar Concentration (CMC), the persulfate decomposition rate decreased, likely due to the formation of micelles. However, as the micelles started to be destroyed, the decomposition rate of the oxidant increased gradually and the highest rate was observed when the concentration of surfactant was close to the CMC. When no micelle was left in the solution, the decomposition rate of the oxidant waned to a low value. Thus, coupling the surfactant and the oxidant can be effective for the degradation of hydrocarbon contaminants. Micelles bring part of the hydrocarbon into the aqueous phase and then the micelles are destroyed by the oxidant that can also degrade the hydrocarbon effectively over time.

How to cite: Abolhosseini, P., Robert, T., Martel, R., and Kaur Brar, S.: Effect of surfactant concentration on the decomposition rate of alkaline activated persulfate, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-2112, https://doi.org/10.5194/egusphere-egu22-2112, 2022.

09:03–09:13
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EGU22-2970
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ECS
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solicited
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Virtual presentation
Atefeh Vafaie, Jordi Cama, and Josep M Soler

CO2 storage in deep geological formations (e.g., saline aquifers) is essential for global warming mitigation. Storage of large amounts of CO2 in the saline aquifers results in acidification of the resident brine, inducing chemical reactions that change the pore structure of the host rock. Hence, the hydromechanical properties of the host rock are likely to alter, which affects the long-term injectivity and mechanical integrity of the reservoir.

To improve our understanding of the alteration of carbonate rocks after the injection of CO2, we have conducted percolation experiments under supercritical CO2 conditions. CO2-saturated water was injected at a constant rate of 0.15 mL/min through cylindrical core samples of Pont Du Gard limestone (diameter of 2.5 cm and length of ~5 cm) at 100 bar PCO2 and 60°C for 14 and 28 days. Fluid chemistry analyses were combined with X-ray microtomography imaging (XCMT) and porosity, permeability, and ultrasonic waves velocity (i.e., compressional and shear) measurements to assess the induced changes in rock properties.

Measured chemical parameters of the effluent solutions revealed rapid calcite dissolution correlating with 4% and 9.6% porosity enhancements for the 14-day and 28-day injections, respectively. Porosity enhancement affected mostly the inlet of the cores. Permeability increased by three orders of magnitude in both cases (from 10-14 to 10-11 m2). XCMT images disclosed that the substantial increase in permeability coincides with the formation of large wormholes along the cores, likely controlled by their intrinsic heterogeneity. Ultrasonic waves velocity measurements under ambient conditions demonstrated that the observed alterations in the pore structures degrade the mechanical stiffness of the rock by up to 40%. Our findings provide insight into the key role of natural heterogeneity in the reactivity of the rock and in the resulting evolution of its hydromechanical properties during CO2 storage.

How to cite: Vafaie, A., Cama, J., and M Soler, J.: Effect of CO2-rich water injection on the hydromechanical properties of Pont Du Gard limestone , EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-2970, https://doi.org/10.5194/egusphere-egu22-2970, 2022.

09:13–09:20
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EGU22-3303
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ECS
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Virtual presentation
Liangwei Xu, Lei Chen, Keji Yang, and Hao Wei

         Shale is an unconventional and complex oil-bearing system with the trinity of source, reservoir and cap. The coupling evolution of thermal maturation hydrocarbon generation, diagenesis and nanoscale porosity is the key scientific problem affecting the accumulation and accumulation of shale gas. In this research, the low matured marine shale of Mesoproterozoic Xiamaling shale in Zhangjiakou, Hebei were selected to conduct the thermal simulation experiments, then the pyrolysis products at each temperature point were recovered and were subject to an ongoing multidisciplinary analytical program. The simulation experiment results show that, in the process of simulated temperature increasing, the maturity of the shale sample is risen generally. the role of hydrocarbon expulsion of the shale at the same time, also to form the inner groove and the shrinkage hole edge groove organic matter more, side by side out of a large number of organic acid, the acid fluid for inorganic pore formation and evolution of simulated sample plays an important role in promoting, It also affects the diagenetic evolution of mud shale. Along with the hydrocarbon generation and expulsion, shale also forms a large number of internal multi-pore and contractive margin pores, and expel a large number of organic acids. These acidic fluids play an important role in promoting the generation and evolution of inorganic pores in the simulated samples, and also affect the diagenetic evolution process of shale.

        The increased temperature accelerates the dissolution of unstable brittle minerals and produces dissolution pores, promotes the transformation of clay minerals, and accelerates the formation and development of clay mineral pores. The nanoscale pore diameter did not change significantly during the simulation process, while the pore volume decreased first and then increased, reaching the minimum and maximum values at 350°C and 650°C, respectively. The surface area of micropores and mesoporous pores firstly decreased and then increased, reaching the minimum value at 350°C, while the surface area of macropores firstly increased and then decreased, reaching the minimum value and maximum value at 350°C and 650°C, respectively(Figure 1).

Figure 1. The pore volume and surface area variation characteristics of micropore (a,a'), mesopore(b, b'), macropore(c, c') during the increase of the thermal temperature.

         The diagenetic evolution during simulated temperature rise can be divided into four stages, and the main diagenetic types are dissolution, clay mineral transformation, thermal maturation hydrocarbon generation, compaction and recrystallization. In our research, the diagenetic evolution process and pore evolution model of shale were roughly divided, and the coupling evolution model of thermal mature hydrocarbon generation, diagenesis and pore structure of shale was established based on thermal simulation experiment (Figure 2).

Figure 2. Comprehensive diagram of the diagenetic evolution sequence and pore evolution model based on the hydrous pyrolysis experiment

 

         The coupling evolution model  provides qualitative and quantitative characterization and evaluation methods for hydrocarbon generation, diagenesis and nanoscale pore structure evolution of organic-rich shale. 

 

How to cite: Xu, L., Chen, L., Yang, K., and Wei, H.: Evolution characteristics and model of nanosclae pores in organic-rich shale during thermal maturation, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-3303, https://doi.org/10.5194/egusphere-egu22-3303, 2022.

09:20–09:27
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EGU22-3823
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ECS
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On-site presentation
Mariana Vasconcelos Barroca and Gilboa Arye

A new generation of non-fumigant nematicides has recently been introduced and is essential to enable efficient and sustainable agricultural production. Fluopyram (FL) is a new compound with a novel mode of action and an improved safety profile. The aim of this study was to quantify the adsorption and transport of FL in 3 soils with different texture under increasing water flows. Initially, equilibrium adsorption isotherms were measured by batch method. Then, FL transport characteristics were analyzed by flowthrough experiments under saturated flow conditions in soil columns. A pulse input of FL was given together with Bromide (Br), used as a conservative tracer. The flowthrough experiments were performed with 3 different soil types, loamy sand, loam and clay under 3 water flow rates, 0.3, 1 and 4 ml min-1, then analyzed and simulated with the convection–dispersion equation (CDE). Equilibrium and kinetic reaction terms were employed to consider sorption of FL. The adsorption isotherms of FL exhibited linear behavior for all soils, with distribution coefficient (Kd) varying from 0.72 to 1.87 L Kg-1 for loam and clay respectively. The established breakthrough curves (BTCs) obtained for bromide exhibited a symmetrical pattern, regardless of soil texture and flow rates, with an average of 100% of Br recovered, suggesting that physical equilibrium is prevailing in all columns. The FL BTCs exhibited sharp increase in concentration after pulse input and long tailing during leaching phase, not fully completed after leaching for 17 pore volumes (PV). The experimental mass balance demonstrated a maximum of 90% recovery on sandy soil and a minimum of 79% in clayey texture. This might indicate that FL has fast adsorption on soil and slow desorption kinetics or even some irreversible adsorption. To understand better the processes affecting FL transport in soils, two models of solute transport were used, a Two-sites sorption model (TSM) and Two-kinetic sites model. When irreversibility was assumed, both models underestimated the tailing of BTCs, trending the curve to zero; showing that instead of irreversible desorption, the long-term leaching behavior is due to a very slow desorption rate. All the models could describe well the adsorption process and confirmed that part of FL has quick adsorption in soil which is in agreement with the low mobility observed. Further evaluation on FL transport characteristics and the adequacy of the different numerical model will be discussed. 

How to cite: Vasconcelos Barroca, M. and Arye, G.: Mobility of Fluopyram in soils under saturated flow conditions, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-3823, https://doi.org/10.5194/egusphere-egu22-3823, 2022.

09:27–09:34
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EGU22-3964
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ECS
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On-site presentation
Maximilian F. Stoll, Roman Stocker, and Joaquin Jimenez-Martinez

Natural porous systems, like soils and aquifers, are physically and chemically highly heterogeneous. Microorganisms inhabiting these environments are therefore exposed to heterogeneous fluid flow velocities and nutrient landscapes. Bacteria capable of biasing their motion to swim along chemical gradients – known as chemotaxis – profit from their ability to localize and navigate towards nutrient hot spots, such as soil aggregates or plant roots.
We propose a novel experimental microfluidic platform to study chemotaxis at the pore-scale, allowing full optical access to the pore space and simultaneously enabling control over the spatio-temporal availability of nutrients. The microfluidic device contains hydrogel features, acting as nutrient hotspots, embedded in a porous medium, made out of transparent polydimethylsiloxane (PDMS) pillars. Nutrients are transported by diffusion from the access channels through the hydrogel into the porous medium, where they are released. The generated nutrient gradients downstream of the hotspots under flow conditions drive the swimming of chemotactic bacteria.
This approach enables the study of subsurface processes at the pore-scale under more realistic conditions, and shed new light onto the influence of physical and chemical heterogeneity on bacterial dispersion and residence time in the subsurface.

Keywords: porous media, soil, chemotaxis, microfluidics, heterogeneity

How to cite: Stoll, M. F., Stocker, R., and Jimenez-Martinez, J.: A pore-scale study of bacterial chemotaxis with segregated and controlled nutrient sources, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-3964, https://doi.org/10.5194/egusphere-egu22-3964, 2022.

09:34–09:41
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EGU22-5191
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ECS
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On-site presentation
Guido Gonzalez-Subiabre, Daniel Fernàndez-Garcia, Michela Trabucchi, and Jesús Carrera

Chaotic advection can be created by engineered sequence of extraction and injection of groundwater in aquifers and by creating an engineered oscillatory flow. It has been used in a wide range of applications, including enhancement of degradation during aquifer remediation, in-situ leaching of metals to enhance mining recovery, and dissipation of energy in geothermal systems. Most of these works are based on numerical simulations and little experimental evidence are reported in the literature. In this work, we analyze how an engineered oscillatory flow can favor mixing-induced precipitation, increasing the total amount and the extension of precipitation zone, with the objective to provide new corrective measures based on permeability reduction. For instance, one can isolate a target aquifer region hydraulically by creating an impervious barrier in the mixing zone. Laboratory experiments were used to study the effect of chaotic advection on mixing-induced precipitation. The experiments were performed in a transparent horizontal two-dimensional tank made of plexiglass filled with glass beads. In the experimental investigation, two different chemical solutions containing CaCl and NaCO3 were injected in separate inlet ports with different concentration. oscillatory flow was created by tuning the inflow rate, we analyze the effect of different injection rates on precipitation. As a result, a calcite precipitate layer with different width was formed between the individual solutions. Color tracer tests were injected before and after the experiment to visualize the impact of precipitation.

How to cite: Gonzalez-Subiabre, G., Fernàndez-Garcia, D., Trabucchi, M., and Carrera, J.: Effect of chaotic advection generated by oscillatory flow on mixing-induced precipitation, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-5191, https://doi.org/10.5194/egusphere-egu22-5191, 2022.

Coffee break
10:20–10:30
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EGU22-5286
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solicited
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On-site presentation
Alessandro Comolli, Fabian Brau, and Anne De Wit

The understanding of the dynamics of reaction diffusion (RD) fronts is crucial for a wide variety of applications in chemistry, biology, physics and ecology, and it is especially important for hydrogeological problems involving chemical reactions. Reactive transport in geological media is generally controlled by the interplay of physical and chemical processes, which can give rise to complex dynamics of the reaction front. An important subset of RD fronts is represented by autocatalytic fronts, for which it is well known that the coupling of diffusion and chemical processes gives rise to self-organization phenomena and pattern forming instabilities [1]. When the initial interface between the reactant and the catalyst is a straight line, the autocatalytic front behaves as a solitary wave, which means that the shape of the front remains unchanged as it travels towards the nonreacted species [2]. The coupling with uniform advection does not change the picture, provided that the system is described in the proper comoving reference frame.

However, in this work we show that the geometrical properties of the injection source have a significant impact on the reaction front dynamics. Indeed, if the injection of one reactant into the other is performed radially at a constant flow rate, the pre-asymptotic dynamics of the front is strongly affected by the nonuniform velocity field. Moreover, although at long times the front still behaves as a solitary wave, the efficiency of the reaction is strongly increased in virtue of the increasing volume occupied by the radial front. We show how injecting a finite amount of reactant into the catalyst gives rise to collapsing fronts and we characterize their dynamics in terms of their position, width and the production rate. In contrast, when the reactant is injected into the catalyst at a constant flow rate, a stationary regime is reached where, unlike the case of solitary waves, the autocatalytic front does not move.      

 

References:

[1] I. R. Epstein and J. A. Pojman, An Introduction to Nonlinear Dynamics: Oscillations, Waves, Patterns, and Chaos (Oxford University Press, Oxford, 1998)

[2] P. Gray, K. Showalter, and S. K. Scott, J. Chim. Phys. 84, 1329 (1987)

How to cite: Comolli, A., Brau, F., and De Wit, A.: Effect of radial geometry on autocatalytic reaction-diffusion-advection fronts , EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-5286, https://doi.org/10.5194/egusphere-egu22-5286, 2022.

10:30–10:37
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EGU22-6000
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ECS
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On-site presentation
Ilan Ben-Noah, Shmulik P. Friedman, Brian Berkowitz, Juan J. Hidalgo, and Marco Dentz

Air saturation degree and flow pattern significantly affect physical, biological, and chemical processes in natural and industrial multiphase systems. However, despite long-standing and current research of multiphase flow, the predictive capabilities in conditions where unstable flow patterns prevail and their consequence on the phase distribution remain extremely limited.

We demonstrate the strong coupling between flow dynamics and phase saturation by analyzing experimental data of steady air injection into background (initially) saturated granular media. Next, we evaluate, using image analysis of recent multiphase experiments in microfluidic devices, the decoupled effect of the saturation degree on the micro-scale distribution of the phases.

We present a simple evaluation of the effects of the steady air flow velocity and of the media’s grain diameter on the macroscale air saturation degree. Using only two variables, one for the matrix (grain diameter) and one for the flow (air velocity), for estimating the air (and water) saturation degree seems to be an oversimplification, especially if one considers the complexity of the two-phase flow problem and the differences between flow patterns and geometries. Nevertheless, the suggested power-law model explains about 90% of the value of the phase saturation across a wide range of saturation degrees and different flow patterns and geometries. Moreover, analysis of this data set reveals a positive effect of both flow velocity and grain diameter on the air saturation degree. Using dimensional analysis, we conclude that viscous and buoyancy forces increase air saturation while capillary forces decrease the saturation degree. Our findings also suggest a significant effect of inertial forces on air saturation in coarse granular media (glass beads). The effect of phase saturation on the flow pattern is significant as deduced from the two extremum conditions of continuum air flow in dry media and predominant unstable flow in initially water-saturated media. However, the effects of the air saturation and flow dynamics cannot be easily evaluated as these are strongly correlated. Recent experimental studies of nearly simultaneous steady air and water injection into microfluidic devices allow a morphological analysis of the phase distribution (e.g., water-filled pore size distribution, coordination number distribution), decoupled from the flow dynamics, i.e., for different saturation degrees of the same capillary number and vice-versa.

Quantifying the impact of macroscale phase saturation and flow dynamics on microscale phase distribution will enable a better prediction of the flow patterns (at the different scales), the local flow velocity distribution, and the effective hydraulic characteristics of the media. In this context, this work, for example, can refine Buckingham’s “law” for different capillary equilibrium conditions.

How to cite: Ben-Noah, I., P. Friedman, S., Berkowitz, B., J. Hidalgo, J., and Dentz, M.: Forced air and water flow in porous media – Dynamics, Saturation degree, and phase distribution, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-6000, https://doi.org/10.5194/egusphere-egu22-6000, 2022.

10:37–10:44
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EGU22-6606
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ECS
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Virtual presentation
Huhao Gao, Alexandru Tatomir, Hiwa Abdullah, and Martin Sauter

The kinetic interface-sensitive (KIS) tracer, relying on a zero-order reaction on the fluid-fluid interface, is a newly developed method to measure the fluid-fluid interfacial area (FIFA) in drainage processes. The concentration of the reaction product, obtained by measuring the water samples after the breakthrough, is interpolated with numerical model to determine the FIFA. However, a major limitation of the previous method is that the volume of available water sample is highly dependent on the sand type and the system parameters, and the measurement is not applicable when the water sample is not sufficient. An alternative is to apply the KIS tracer in the “push-pull” test, meaning the drainage process is followed by an imbibition process with the flow direction reversed. This study applies the pore-scale numerical simulation and the column experiment to study the KIS tracer reactive transport during a push-pull test. The breakthrough curve of the product concentration is interpolated with both macro-scale numerical model and a modified analytical solution for the push-pull process. It is found the shapes of the concentration breakthrough curves from the pore-scale simulations and the column experiments are fit, showing a non-linear descending trend with respect to time. The KIS tracer reactive transport process in the push-pull test and the validation of the measured FIFA from the concentration breakthrough curve, are demonstrated based on the pore-scale simulation results. Finally, for the (n-octane/water) displacement process in the column packed with the glass beads with diameter of 240 μm (at the capillary number of 5×10-7), the FIFA is measured 210 m-1 at the water saturation of 0.33, which is consistent with some literature data.

 

How to cite: Gao, H., Tatomir, A., Abdullah, H., and Sauter, M.: A push-pull kinetic interface-sensitive tracer method to quantify the fluid-fluid interfacial area in dynamic two-phase flow in porous media, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-6606, https://doi.org/10.5194/egusphere-egu22-6606, 2022.

10:44–10:51
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EGU22-8398
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On-site presentation
Mohammad Masoudi, Mohammad Nooraiepour, and Helge Hellevang

The process of mineral precipitation and crystal growth begins with nucleation, which is usually overlooked in reactive transport simulators. Nucleation controls the location and timing of solid mineral formation in porous media. For an accurate prediction of the hydrodynamics of the porous medium after mineral precipitation, it is crucial to know the spatial distribution of stable secondary nuclei. We developed a novel probabilistic nucleation approach wherein induction time is treated as a random variable in order to better understand the nucleation process. The probabilistic induction time statistically spreads around the measured or reported induction time, either obtained from experiments or approximated by the exponential nucleation rate equation suggested by the classical nucleation theory (CNT). In this study, we used the classical nucleation theory. The location and time of nucleation are both probabilistic in our model, affecting transport properties at different time and length scales.

We developed a pore-scale Lattice Boltzmann reactive transport model incorporated with the new probabilistic nucleation model to investigate the effect of nucleation rate and reaction rate on the extent, distribution, and precipitation pattern of the solid phases. The simulation domain is a 2D substrate with an infinite source of the supersaturated solution. We use Shannon entropy to measure the disorder of the spatial mineral distributions. The results of the simulations show that all the reactions follow similar random behavior with different Gauss-Laplace distributions. The simulation scenarios start from a fully ordered system with no solid precipitation on the substrate (entropy of 0). Entropy starts to increase as the secondary phase precipitates and grows on the surface until it reaches its maximum value (entropy of 1). Afterward, the overall disorder declines as more surface areas are being covered, and eventually, entropy approaches a constant value. The results indicate that the slower reactions have longer windows of the probabilistic regime before entering the deterministic regime. The outcomes provide the basis for implementing mineral nucleation and growth for reactive transport modeling across time-scales and length-scales.

How to cite: Masoudi, M., Nooraiepour, M., and Hellevang, H.: On the effect of probabilistic nucleation on the distribution of mineral precipitates in porous media, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-8398, https://doi.org/10.5194/egusphere-egu22-8398, 2022.

10:51–10:58
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EGU22-9633
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Virtual presentation
Manman Hu, Qingpei Sun, Christoph Schrank, and Klaus Regenauer-Lieb

Patterns in nature are often interpreted as a product of reaction-diffusion processes which result in dissipative structures. Thermodynamic constraints allow prediction of the final state with the dynamic evolution of the micro-processes refrained. Here we introduce a new micro-physics based approach that allows us to discover a family of soliton-like excitation waves - coupling the micro-scale cross-constituent interactions to the large scale dynamic behaviour of the open system. These waves can appear in hydromechanically coupled porous media under external loads. They arise when mechanical forcing of the porous skeleton releases internal energy through a phase change, leading to tight coupling of the pressure in the solid matrix with the dissipation of the pore fluid pressure. In order to describe these complex multiscale interactions in a thermodynamic consistent framework, we consider a dual-continuum system, where the large-scale continuum properties of the matrix-fluid interaction are described by a reaction-self diffusion formulation, and the small-scale release of internal energy by a reaction-cross diffusion formulation that spells out the macroscale reaction and relaxes the adiabatic constraint on the local reaction term in the conventional reaction-diffusion formalism. Using this approach, we recover the familiar Turing bifurcations (e.g., rhythmic metamorphic banding), Hopf bifurcations (e.g., Episodic Tremor and Slip), and present the new excitation wave phenomenon. The parametric space is investigated numerically and compared to  serpentinite deformation in subduction zones.

How to cite: Hu, M., Sun, Q., Schrank, C., and Regenauer-Lieb, K.: Dynamic instabilities caused by reaction-cross-diffusion waves in compacting porous media, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-9633, https://doi.org/10.5194/egusphere-egu22-9633, 2022.

10:58–11:05
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EGU22-10079
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ECS
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On-site presentation
Darío Martín Escala and Alberto Pérez Muñuzuri

Interfacial fluid instabilities are ubiquitous in Nature and are responsible for many important phenomena. In some cases, they play a constructive role like in the redistribution of energy in a system but, in some other cases, the role is destructive and may pose a serious threat to technical or industrial applications. In most cases, these fluids involve reactants that are known to modify the instability itself.

Fingering instabilities are special cases of fluid instabilities that occur when a high mobility fluid displaces a low mobility one [1]. Processes like enhanced oil recovery or other fluid displacements in porous media, such as chromatography, are examples in which the existence of fingering instability is crucial for the overall extraction performance. At a laboratory scale, these instabilities are studied in experimental arrangements known as Hele-Shaw cells. A particularity of these cells is that the flow inside them is representative of the flow in porous media.

In this work, we propose a chemical system likely to produce instabilities. We endow it with the appropriate chemical reactions at the interface that make it possible to control the activation or deactivation of the fingering instability at will. In particular, we consider two different fluids with different viscosities and analyze the displacement of one fluid by the other injected into a radial Hele-Shaw cell. We studied two different scenarios depending on which fluid is used as displacing/displaced solution [2].

In the first case, where the most viscous fluid displaces the less viscous one (initially stable configuration), pattern formation is observed when the characteristic flow and reactive timescales are similar. The patterns show complex dynamics in which fingers not only grow but move forward/backward. In the second case (initially unstable configuration), the unfavorable mobility ratio produces complex wormhole structures similar to those observed in dissolving rock fractures [3,4]. The displacement stabilizes when flow, diffusive, and reactive timescales are comparable.

We extensively characterized and numerically modeled both scenarios. Our results establish the basis to control fluid instabilities that may arise in a broad variety of contexts.  

REFERENCES:

[1] Homsy, G. M. (1987). Viscous fingering in porous media. Annual review of fluid mechanics, 19(1), 271-311.

[2] Escala, D. M., & Muñuzuri, A. P. (2021). A bottom-up approach to construct or deconstruct a fluid instability. Scientific reports, 11(1), 1-16.

[3] Szymczak, P., & Ladd, A. J. C. (2009). Wormhole formation in dissolving fractures. Journal of Geophysical Research: Solid Earth, 114(B6).

[4] Kalia, N., & Balakotaiah, V. (2007). Modeling and analysis of wormhole formation in reactive dissolution of carbonate rocks. Chemical Engineering Science, 62(4), 919-928.

How to cite: Escala, D. M. and Pérez Muñuzuri, A.: Complex Pattern Formation and Viscous Fingering Stabilization in Radial Flow, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-10079, https://doi.org/10.5194/egusphere-egu22-10079, 2022.

11:05–11:12
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EGU22-11132
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ECS
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On-site presentation
Hiwa Abdullah, Alexandru Tatomir, and Martin Sauter

The kinetic interface sensitive (KIS) tracers have been the focus of research in the past decade, as a new, reactive tracer method to estimate the interfacial area between immiscible fluids in porous media. We present here a novel experimental approach to measure the capillary associated fluid-fluid interfacial area using the KIS tracers in simultaneous two-phase flow conditions. The new approach is applied in a sand column filled with glass-beads (d50 = 170µm). Four laboratory experiments are performed in a simultaneous two-phase injection scheme using different fractional flow ratios (Flow rate of wetting phase: total flow rate). The different fractional ratios create different saturations inside the column, which correlate to different fluid-fluid interfacial areas. The new method, introduces also a new analytical method to handle reacted by-product concentration data acquired, different from the KIS tracer method in dynamic conditions. By comparing the results to other established techniques reported in the literature (i.e., interfacial partitioning tracer test and computed micro-tomography) used to measure fluid-fluid interfacial area we observe a good agreement.  The capillary associated interfacial area increases with decreasing wetting saturation until a maximum value, which then drops near the residual saturation. The maximum capillary associated interfacial area occurs at wetting saturation ranges between 0.45 < Sw < 0.6, which is slightly shifted towards the higher wetting saturation when compared to the other techniques. Furthermore, the results are simulated using a Darcy-scale reactive transport multiphase flow in porous media numerical model.

How to cite: Abdullah, H., Tatomir, A., and Sauter, M.: Experimental approach to measure capillary associated interfacial area using kinetic interface sensitive tracers in a simultaneous two-phase flow, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-11132, https://doi.org/10.5194/egusphere-egu22-11132, 2022.

11:12–11:19
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EGU22-11813
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ECS
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Presentation form not yet defined
Shabina Ashraf, Jayabrata Dhar, François Nadal, Patrice Meunier, and Yves Méheust

More than 60% of greenhouse gas emissions are due to CO2 released from fossil fuels and industrial processes [1]. It is expected that by 2035, the expected increase in CO2 emissions will be 37.2 Gt/yr [2]. To reduce the resulting further adverse effects in climate changes, geological sequestration of CO2 provides an effective solution for carbon capture and storage (CCS) [2-4]. Dissolution trapping of CO2 in deep saline aquifers is a trapping mechanism that allows for long term storage. When CO2 is injected into the subsurface geological layers, the supercritical CO2 (sCO2) dissolves into the aquifer’s aqueous solution positioned below. The formation of a layer of CO2-enriched brine at the upper interface of the liquid domain results in unstable stratification which evolves into gravitational convection [2-5].

To evaluate the storage capacity and the efficiency of the trapping, it is necessary to understand the dynamics of the instabilities and convection, and the affect of granular media properties on them. To do so, we perform a 2D experimental study in a 3D granular medium and use Darcy scale simulations to complement our experimental findings [6]. Analog experiments are performed by using two miscible fluids with a density contrast between them. In doing so we decouple the gravitational instability process from the dissolution process; the latter is not modeled in our experiment. We match the refractive index of the fluids to that of the granular medium to allow for optical measurement of the concentration field. We observe that there is substantial difference in convection development time scales between the experimental results and the Darcy scale simulations performed with the experimental macroscopic parameters (porosity, permeability, dispersivity lengths, density contrast). We attribute this to the role played by pore scale heterogeneity of the velocity field, which cannot be predicted by Darcy scale models. This would suggest that Darcy scale simulations [2, 4,6] significantly overestimate the typical time scale of the convection.

[1] Contribution of Working Group III to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change, IPCC 2014.

[2] Emami-Meybodi, H., Hassanzadeh, H., Green, C. P., & Ennis-King, J. (2015). Convective dissolution of CO2 in saline aquifers: Progress in modeling and experiments. International Journal of Greenhouse Gas Control, 40, 238-266.

[3] Bachu, S. (2008). CO2 storage in geological media: Role, means, status and barriers to deployment. Progress in energy and combustion science, 34(2), 254-273.

[4] Pau, G. S., Bell, J. B., Pruess, K., Almgren, A. S., Lijewski, M. J., & Zhang, K. (2010). High-resolution simulation and characterization of density-driven flow in CO2 storage in saline aquifers. Advances in Water Resources, 33(4), 443-455.

[5] Nadal, F., Meunier, P., Pouligny, B., & Laurichesse, E. (2013). Stationary plume inducedby carbon dioxide dissolution. Journal of Fluid Mechanics, 719, 203-229.

[6] Dhar, J., Meunier, P., Nadal, F. & Méheust, Y. (2021). Convection dissolution of CO2 in  2D and 3D porous media: the impact of hydrodynamic dispersion. Submitted to Physics of Fluids.

How to cite: Ashraf, S., Dhar, J., Nadal, F., Meunier, P., and Méheust, Y.: Experimental study of miscible Rayleigh-Taylor convection in a granular porous medium, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-11813, https://doi.org/10.5194/egusphere-egu22-11813, 2022.

11:19–11:26
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EGU22-12516
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ECS
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Virtual presentation
Edward Andrews, Alistair Jones, Ann Muggeridge, and Samuel Krevor

Low salinity water flooding is a promising enhanced oil recovery technique that has been observed, in experiments over a range of scales, to increase oil production by up to 14% in some systems. However, there is still no way of reliably predicting which systems will respond favourably to the technique. This shortcoming is partly because of a relative lack of pore scale observations of low salinity water flooding. This has led to a poor understanding of how mechanisms on the scale of micrometres lead to changes in fluid distribution on the scale of centimetres to reservoir scales. In this work, we present the first systematic comparison of the pore scale response to low salinity flooding across multiple sandstone samples. We use X-ray micro-CT scanning to image unsteady state experiments of tertiary low salinity water flooding in Berea, Castlegate, and Bunter sandstone micro-cores. We observe fluid saturations and characterise the wetting state of samples using imagery of fluid-solid fractional wetting and pore occupancy analysis. In the Berea sample, we observed an additional oil recovery of 3 percentage points during low salinity water flooding, with large volumes of oil displaced from small pores but also re-trapping of mobilised oil in large pores. In the Bunter sandstone, we observed 4 percentage point additional recovery with significant displacement of oil from small pores and no significant retrapping of oil in large pores. However, in the Castlegate sample, we observed just 1 percentage point of additional recovery and relatively small volumes of oil mobilisation. We observe a significant wettability alteration towards more water-wet conditions in the Berea and Bunter sandstones, but no significant alteration in the Castlegate sample. We hypothesise that the pore structure, specifically the connectivity of the largest pores in each sample, significantly affected production. This work gives the first pore scale insights into the role of pore geometry and topology on the mobilisation and retrapping of oil during low salinity water flooding.   

How to cite: Andrews, E., Jones, A., Muggeridge, A., and Krevor, S.: Identification of the leading role of pore structure in determining recovery during low salinity water flooding , EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-12516, https://doi.org/10.5194/egusphere-egu22-12516, 2022.

11:26–11:33
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EGU22-13563
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Presentation form not yet defined
Yves Méheust, Jayabrata Dhar, Patrice Meunier, and François Nadal

Convective dissolution is the process by which CO2 injected in geological formations dissolves into the aqueous phase and thus remains stored perennially by gravity. It can be modeled by buoyancy-coupled Darcy flow and solute transport. The transport equation should include a diffusive term accounting for hydrodynamic dispersion, wherein the effective diffusion coefficient is proportional to the local interstitial velocity. We investigate the impact of the hydrodynamic dispersion tensor on convective dissolution in two-dimensional (2D) and three-dimensional (3D) homogeneous porous media. Using a novel numerical model we systematically analyze, among other observables, the time evolution of the fingers’ structure, dissolution flux in the quasi-constant flux regime, and mean concentration of the dissolved CO2; we also determine the onset time of convection, ton. For a given Rayleigh number Ra, the efficiency of convective dissolution over long times is controlled by ton. For porous media with a dispersion anisotropy commonly found in the subsurface, ton increases as a function of the longitudinal dispersion’s strength (S), in agreement with previous experimental findings and in contrast to previous numerical findings, a discrepancy which we explain. More generally, for a given strength of transverse dispersion, longitudinal dispersion always slows down convective dissolution, while for a given strength of longitudinal dispersion, transverse dispersion always accelerates it. Furthermore, systematic comparison between 2D and 3D results shows that they are consistent on all accounts, except for a slight difference in ton and a significant impact of Ra on the dependence of the finger number density on S in 3D.

How to cite: Méheust, Y., Dhar, J., Meunier, P., and Nadal, F.: Convective dissolution of Carbon Dioxide in two- and three-dimensional porous media: the impact of hydrodynamic dispersion, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-13563, https://doi.org/10.5194/egusphere-egu22-13563, 2022.

11:33–11:40
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EGU22-13570
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ECS
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On-site presentation
Pamela Knoll and Anne De Wit

The reduction of carbon dioxide concentration in the atmosphere has become an important objective to diminish the predicted exponential increase in global temperatures. A promising long-term solution is carbon capture, and sequestration (CCS), whereby CO2 is injected into saline aquifers containing high concentrations of divalent cations leading to the mineralization of carbonate salts. These precipitation reactions provide a potential long-term solution for storing and preventing reentry of this greenhouse gas into the atmosphere. Our study aims to understand the influence of the initial host solution composition on CCS. Using two glass plates separated by a thin gap (~1 mm), we steadily inject CO2 gas above an alkaline aqueous solution of either calcium chloride and/or magnesium chloride and monitor the convective uptake of CO2 and subsequent mineralization into calcium carbonate (e.g., calcite, aragonite, and vaterite), magnesium carbonate (e.g., hydromagnesite), or calcium magnesium carbonate (e.g., dolomite). The buoyancy-driven convective dynamics from the dissolution of CO2 is monitored using schlieren imaging techniques. In addition, a pH indicator in the initial metal salt solution shows its acidification from the continuous uptake of CO2. The mineral products are analyzed using X-ray diffraction, Raman spectroscopy and scanning electron microscopy to determine the composition, crystal structure, and crystal habit.

How to cite: Knoll, P. and De Wit, A.: The Effect of Calcium and Magnesium Ions on CO2 Convective Dissolution and Carbonate Precipitation, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-13570, https://doi.org/10.5194/egusphere-egu22-13570, 2022.