scholarly journals Implementing the Variability of Crystal Surface Reactivity in Reactive Transport Modeling

2021 ◽  
Author(s):  
Torben Prill ◽  
Cornelius Fischer ◽  
Pavel Gavrilenko ◽  
Oleg Iliev
Keyword(s):  
Contaminated Soils ◽  
Reactive Transport ◽  
Transport Model ◽  
Crystal Surface ◽  
Reaction Rates ◽  
Surface Reactivity ◽  
Reservoir Rock ◽  
Intrinsic Variability ◽  
Multiple Systems ◽  
The Difference

AbstractCurrent reactive transport model (RTM) uses transport control as the sole arbiter of differences in reactivity. For the simulation of crystal dissolution, a constant reaction rate is assumed for the entire crystal surface as a function of chemical parameters. However, multiple dissolution experiments confirmed the existence of an intrinsic variability of reaction rates, spanning two to three orders of magnitude. Modeling this variance in the dissolution process is vital for predicting the dissolution of minerals in multiple systems. Novel approaches to solve this problem are currently under discussion. Critical applications include reactions in reservoir rocks, corrosion of materials, or contaminated soils. The goal of this study is to provide an algorithm for multi-rate dissolution of single crystals, to discuss its software implementation, and to present case studies illustrating the difference between the single rate and multi-rate dissolution models. This improved model approach is applied to a set of test cases in order to illustrate the difference between the new model and the standard approach. First, a Kossel crystal is utilized to illustrate the existence of critical rate modes of crystal faces, edges, and corners. A second system exemplifies the effect of multiple rate modes in a reservoir rock system during calcite cement dissolution in a sandstone. The results suggest that reported variations in average dissolution rates can be explained by the multi-rate model, depending on the geometric configurations of the crystal surfaces.

scholarly journals Pulsating dissolution of crystalline matter

2018 ◽  
Vol 115 (5) ◽  
pp. 897-902 ◽  
Author(s):  
Cornelius Fischer ◽  
Andreas Luttge
Keyword(s):  
Reactive Transport ◽  
Reaction Rate ◽  
Crystal Surface ◽  
Reaction Rates ◽  
Spatial And Temporal Variability ◽  
Pharmaceutical Sciences ◽  
Material Flux ◽  
Spatially Resolved ◽  
Site Density ◽  
Fluid Saturation

Fluid–solid reactions result in material flux from or to the solid surface. The prediction of the flux, its variations, and changes with time are of interest to a wide array of disciplines, ranging from the material and earth sciences to pharmaceutical sciences. Reaction rate maps that are derived from sequences of topography maps illustrate the spatial distribution of reaction rates across the crystal surface. Here, we present highly spatially resolved rate maps that reveal the existence of rhythmic pulses of the material flux from the crystal surface. This observation leads to a change in our understanding of the way crystalline matter dissolves. Rhythmic fluctuations of the reactive surface site density and potentially concomitant oscillations in the fluid saturation imply spatial and temporal variability in surface reaction rates. Knowledge of such variability could aid attempts to upscale microscopic rates and predict reactive transport through changing porous media.

Mineral surface reactivity: mechanisms and concepts

2021 ◽  
Author(s):  
Cornelius Fischer
Keyword(s):  
Reactive Transport ◽  
Large Scale ◽  
Fluid Transport ◽  
Crystal Surface ◽  
Solid Material ◽  
Surface Reactivity ◽  
Small Scale ◽  
Critical Surface ◽  
Mechanistic Understanding ◽  
Diagenetic Reactions

<p>Diagenetic reactions in sediments and sedimentary rocks are controlled by both fluid transport and surface reactivity. In this chapter, the major focus is on the effect of crystal surface reactivity and its variability. The “energetic landscape” of the solid material in contact with the fluid exerts control on reaction type, kinetics, and products. Critical surface processes include sorption, catalysis, dissolution, and precipitation. For diagenetic reactions, the sequence of processes and thus the potential inhibition of subsequent reactions due to surface modifications is of great interest. Consequently, the evolution of porosity and permeability is governed by the chronological sequence of surface reactions during the diagenetic history. This provides feedback to the fluid transport behaviour in the complex porous material. Because of this coupling, numerical approaches address the problem appropriately by the use of reactive transport codes. Pore scale treatment follows mechanisms at the scale of crystal surfaces that form the pore walls of the sedimentary rock. Such surface-chemical exercises require a parametrization that includes mechanistic understanding and connection to first-principles treatment. At larger scales, so-called continuum scale simulation treats fluid transport and fluid-solid reactions in a more generalized quantitative way. While such field-scale treatment is required and applied for multiple challenges, the small-scale mechanistic understanding is still a crucial part of geochemical research. The observed heterogeneity of surface reactivity requires specific upscaling strategies that are not yet reflected in large-scale analysis and predictions.</p>

scholarly journals Chemical Compositions in Salinity Waterflooding of Carbonate Reservoirs: Theory

2021 ◽  
Vol 136 (2) ◽  
pp. 411-429
Author(s):  
M. P. Yutkin ◽  
C. J. Radke ◽  
T. W. Patzek
Keyword(s):  
Ion Exchange ◽  
Reactive Transport ◽  
Carbonate Rock ◽  
Reaction Rates ◽  
Design Tool ◽  
Mineral Dissolution ◽  
Carbonate Reservoirs ◽  
Reservoir Rock ◽  
Chemical Compositions ◽  
Water Wettability

AbstractHigher oil recovery after waterflood in carbonate reservoirs is attributed to increasing water wettability of the rock that in turn relies on complicated surface chemistry. In addition, calcite mineral reacts with aqueous solutions and can alter substantially the composition of injected water by mineral dissolution. Carefully designed chemical and/or brine flood compositions in the laboratory may not remain intact while the injected solutions pass through the reactive reservoir rock. This is especially true for a low-salinity waterflood process, where some finely tuned brine compositions can improve flood performances, whereas others cannot. We present a 1D reactive transport numerical model that captures the changes in injected compositions during water flow through porous carbonate rock. We include highly coupled bulk aqueous and surface carbonate-reaction chemistry, detailed reaction and mass transfer kinetics, 2:1 calcium ion exchange, and axial dispersion. At typical calcite reaction rates, local equilibrium is established immediately upon injection. In SI, we validate the reactive transport model against analytic solutions for rock dissolution, ion exchange, and longitudinal dispersion, each considered separately. Accordingly, using an open-source algorithm (Charlton and Parkhurst in Comput Geosci 37(10):1653–1663, 2011. 10.1016/j.cageo.2011.02.005), we outline a design tool to specify chemical/brine flooding formulations that correct for composition alteration by the carbonate rock. Subsequent works compare proposed theory against experiments on core plugs of Indiana limestone and give examples of how injected salinity compositions deviate from those designed in the laboratory for water-wettability improvement.

Investigation of Smart Waterflooding in Sandstone Reservoirs: Experimental and Simulation Study Part 2

SPE Journal ◽  
2020 ◽  
Vol 25 (04) ◽  
pp. 1670-1680
Author(s):  
Hasan N. Al-Saedi ◽  
Ralph E. Flori ◽  
Mortadha Alsaba
Keyword(s):  
Oil Recovery ◽  
Heavy Oil ◽  
Reactive Transport ◽  
Transport Model ◽  
Divalent Cations ◽  
Surface Reactivity ◽  
Quartz Surface ◽  
Formation Water ◽  
Smart Water ◽  
Original Oil In Place

Summary In a previous work (Al-Saedi et al. 2018c), we studied the effect of mineral composition of cores (using synthetic columns with varying mineralogy) on low-salinity (LS) waterflooding, and we presented a reactive-transport model (RTM) for the water/rock interactions. The results showed that kaolinite has the strongest effect and then quartz because of the high kaolinite surface area, and the most effective complexes were >SiOH (hydroxylated Si), >AlO– (aluminum oxide complex on quartz surface), and >SiO– (silicon mono oxide complex on quartz surface). In this paper, we use the same Bartlesville Sandstone cores (constant mineralogy) for all cases to investigate the effect of water chemistry on water/rock interactions during seawater and smart waterflooding of reservoir sandstone cores containing heavy oil. Oil recovery, surface-reactivity tests, and multicomponent reactive-transport simulation using CrunchFlow (Steefel 2009) were conducted to better understand smart waterflooding. Bartlesville Sandstone cores were saturated with heavy oil and connate formation water. Secondary waterflooding of these cores with formation water (FW) at 25°C resulted in an ultimate oil recovery of approximately 50% original oil in place (OOIP) for all reservoir cores in this study. FW salinity was 104,550 ppm. FW was diluted twice to obtain Smart Water 1 (SMW1). SMW2 was similar to SMW1 but depleted in divalent cations (Ca2+ and Mg2+). SMW3 was also similar to SMW1 but depleted in Mg2+ and SO42−, whereas SMW4 was the same as SMW1 but Ca2+ was diluted 100 times. Seawater (SW) salinity was 48,300 ppm, which is close to the SMW salinity (52,275 ppm). No oil recovery was observed during SMW1 flooding, whereas softening SMW1 (SMW2) resulted in a significant additional oil recovery of OOIP. Depleting Mg2+ and SO42− resulted in additional oil recovery but less than in SMW2. Diluting Ca2+ 100 times was the second-best scenario, after depleted Ca2+ in SMW2. The results of this study showed that the more diluted Ca2+ is in the injected brine, the more additional oil recovery that can be obtained, although the other divalent/monovalent cations/anions were increased or decreased or even depleted. Additional reservoir cores were allocated for surface-reactivity tests. The absence of an oil phase allows us to isolate the important water/rock reactions. The Ca2+, Mg2+, and SO42− effluents for all cores were matched using CrunchFlow, and then further investigations of the water/rock interactions were conducted. The RTM showed that decreasing the Mg2+ concentration will decrease the number of the most effective kaolinite edges Si-O− and Al-O−, but was not as pronounced as that in the presence of Ca2+, which explains why lowering the Mg2+ concentration gives lower additional oil recovery and why lowering the Ca2+ concentration gives higher additional oil recovery.

scholarly journals Chemical Compositions in Salinity Waterflooding of Carbonate Reservoirs: Theory

2020 ◽  
Author(s):  
Maxim Yutkin ◽  
Clayton J. Radke ◽  
Tadeusz Patzek
Keyword(s):  
Mass Transfer ◽  
Ion Exchange ◽  
Reactive Transport ◽  
Carbonate Rock ◽  
Reaction Rates ◽  
Companion Paper ◽  
Contact Angles ◽  
Carbonate Reservoirs ◽  
Reservoir Rock ◽  
Chemical Compositions

Higher oil recovery after waterflood in carbonate reservoirs is attributed to increasing water wettability of the rock that in turn relies on complicated surface chemistry. However, calcite mineral reacts with<br>aqueous solutions, and can alter substantially the composition of injected water by mineral dissolution. Care-<br>fully designed chemical and/or brine flood compositions in the laboratory may not remain intact while the<br>injected solutions pass through the reactive reservoir rock. This is especially true for a low-salinity waterflood<br>process, where some finely-tuned brine compositions can improve flood performances, whereas others cannot.<br>We present a 1D reactive transport numerical model that captures the changes in injected compositions dur-<br>ing water flow through porous carbonate rock. We include highly coupled bulk aqueous and surface carbonate-<br>reaction chemistry, detailed reaction and mass transfer kinetics, 2:1 calcium ion exchange, and axial dispersion.<br>At typical calcite reaction rates, local equilibrium is established immediately upon injection. Using an open-<br>source algorithm (Charlton and Parkhurst 2011), we present a design tool to specify chemical/brine flooding<br>packages that correct for composition alteration by carbonate rock.<br>Here, we present a comprehensive 1D reactive transport model and validate it against analytic solutions<br>for rock dissolution, ion exchange, and longitudinal dispersion, each considered separately. A companion paper<br>compares the proposed theory against experiments on core plugs of Indiana limestone that serve as high velocity<br>probes for reaction-controlled and mass-transfer-controlled dissolution. Finally, in another companion paper,<br>we give examples of how injected salinity compositions deviate from those designed in the laboratory for water-<br>wettability improvement based on contact angles, zeta potentials, surface charge densities, and ion exchange.<br>How to correct the design chemical packages for exposure to reactive rock is also discussed in there.

scholarly journals Chemical Compositions in Salinity Waterflooding of Carbonate Reservoirs: Theory

2020 ◽  
Author(s):  
Maxim Yutkin ◽  
Clayton J. Radke ◽  
Tadeusz Patzek
Keyword(s):  
Mass Transfer ◽  
Ion Exchange ◽  
Reactive Transport ◽  
Carbonate Rock ◽  
Reaction Rates ◽  
Companion Paper ◽  
Contact Angles ◽  
Carbonate Reservoirs ◽  
Reservoir Rock ◽  
Chemical Compositions

Higher oil recovery after waterflood in carbonate reservoirs is attributed to increasing water wettability of the rock that in turn relies on complicated surface chemistry. However, calcite mineral reacts with<br>aqueous solutions, and can alter substantially the composition of injected water by mineral dissolution. Care-<br>fully designed chemical and/or brine flood compositions in the laboratory may not remain intact while the<br>injected solutions pass through the reactive reservoir rock. This is especially true for a low-salinity waterflood<br>process, where some finely-tuned brine compositions can improve flood performances, whereas others cannot.<br>We present a 1D reactive transport numerical model that captures the changes in injected compositions dur-<br>ing water flow through porous carbonate rock. We include highly coupled bulk aqueous and surface carbonate-<br>reaction chemistry, detailed reaction and mass transfer kinetics, 2:1 calcium ion exchange, and axial dispersion.<br>At typical calcite reaction rates, local equilibrium is established immediately upon injection. Using an open-<br>source algorithm (Charlton and Parkhurst 2011), we present a design tool to specify chemical/brine flooding<br>packages that correct for composition alteration by carbonate rock.<br>Here, we present a comprehensive 1D reactive transport model and validate it against analytic solutions<br>for rock dissolution, ion exchange, and longitudinal dispersion, each considered separately. A companion paper<br>compares the proposed theory against experiments on core plugs of Indiana limestone that serve as high velocity<br>probes for reaction-controlled and mass-transfer-controlled dissolution. Finally, in another companion paper,<br>we give examples of how injected salinity compositions deviate from those designed in the laboratory for water-<br>wettability improvement based on contact angles, zeta potentials, surface charge densities, and ion exchange.<br>How to correct the design chemical packages for exposure to reactive rock is also discussed in there.

Relating biomolecular data to denitrification rates in infiltrating river water – insights from enzyme-based reactive transport modelling

2021 ◽  
Author(s):  
Anna Störiko ◽  
Holger Pagel ◽  
Adrian Mellage ◽  
Olaf A. Cirpka
Keyword(s):  
Reactive Transport ◽  
Transport Model ◽  
Reaction Rates ◽  
Poor Correlation ◽  
Gene Transcript ◽  
Single Event ◽  
Reactive Transport Modelling ◽  
Transport Modelling ◽  
Temporal And Spatial ◽  
Denitrification Genes

&lt;p&gt;Biomolecular quantities like gene, transcript or enzyme concentrations related to a specific reaction promise to provide information about the turnover of nutrients or contaminants in the environment. Particularly transcript-to-gene ratios have been suggested to provide a measure for reaction rates but a relationship with rates currently lacks validation.&lt;br&gt;We applied an enzyme-based reactive transport model for denitrification and aerobic respiration at the river-groundwater interface to simulate the temporal and spatial patterns of transcripts, enzymes and biomass under diurnal dissolved oxygen fluctuations.&lt;br&gt;Our analysis showed that transcript concentrations of denitrification genes exhibit considerable diurnal fluctuations, whereas enzyme concentrations and biomass are stable over time. The daily fluctuations in denitrification rates yielded a poor correlation between rates and transcript and enzyme concentrations. Daily averaged reaction rates, however, show a close-to-linear relationship with enzyme concentrations and mean transcript concentrations.&lt;br&gt;Our findings suggest that, under dynamic environmental conditions, single-event sampling may result in the misinterpretation of biomelucular quantities as these relate to reaction rates. A better representation of rates can be achieved via sampling that captures the temporal variability of a particular system.&lt;/p&gt;

scholarly journals Chemical Compositions in Salinity Waterflooding of Carbonate Reservoirs: Theory

2020 ◽  
Author(s):  
Maxim Yutkin ◽  
Clayton J. Radke ◽  
Tadeusz Patzek
Keyword(s):  
Mass Transfer ◽  
Ion Exchange ◽  
Reactive Transport ◽  
Carbonate Rock ◽  
Reaction Rates ◽  
Companion Paper ◽  
Contact Angles ◽  
Carbonate Reservoirs ◽  
Reservoir Rock ◽  
Chemical Compositions

Higher oil recovery after waterflood in carbonate reservoirs is attributed to increasing water wettability of the rock that in turn relies on complicated surface chemistry. However, calcite mineral reacts with<br>aqueous solutions, and can alter substantially the composition of injected water by mineral dissolution. Care-<br>fully designed chemical and/or brine flood compositions in the laboratory may not remain intact while the<br>injected solutions pass through the reactive reservoir rock. This is especially true for a low-salinity waterflood<br>process, where some finely-tuned brine compositions can improve flood performances, whereas others cannot.<br>We present a 1D reactive transport numerical model that captures the changes in injected compositions dur-<br>ing water flow through porous carbonate rock. We include highly coupled bulk aqueous and surface carbonate-<br>reaction chemistry, detailed reaction and mass transfer kinetics, 2:1 calcium ion exchange, and axial dispersion.<br>At typical calcite reaction rates, local equilibrium is established immediately upon injection. Using an open-<br>source algorithm (Charlton and Parkhurst 2011), we present a design tool to specify chemical/brine flooding<br>packages that correct for composition alteration by carbonate rock.<br>Here, we present a comprehensive 1D reactive transport model and validate it against analytic solutions<br>for rock dissolution, ion exchange, and longitudinal dispersion, each considered separately. A companion paper<br>compares the proposed theory against experiments on core plugs of Indiana limestone that serve as high velocity<br>probes for reaction-controlled and mass-transfer-controlled dissolution. Finally, in another companion paper,<br>we give examples of how injected salinity compositions deviate from those designed in the laboratory for water-<br>wettability improvement based on contact angles, zeta potentials, surface charge densities, and ion exchange.<br>How to correct the design chemical packages for exposure to reactive rock is also discussed in there.

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