A numerical simulation method for CO2 mineralization and sequestration in saline aquifers at the pore scale, achieving dynamic coupling of dissolution and precipitation.
By combining the DBS equation and ADE equation with the ion product-solubility product judgment statement, a numerical simulation method for CO2 mineralization and storage in saline aquifers with dynamic coupling of dissolution and precipitation is constructed. This method solves the problem of decoupling of spatiotemporal scale and multi-field coupling in the CO2 mineralization and storage process in saline aquifers, achieves high-precision pore-scale simulation, dynamically tracks the dissolution and precipitation process, and simplifies the solution process.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CHENGDU UNIVERSITY OF TECHNOLOGY
- Filing Date
- 2026-03-27
- Publication Date
- 2026-06-23
AI Technical Summary
Existing technologies for simulating CO2 saline aquifer mineralization and storage suffer from problems such as spatiotemporal scale mismatch, difficulty in decoupling multi-field coupling, large computational load, and insufficient accuracy in characterizing microscopic mechanisms in traditional numerical simulations.
A pore-scale numerical simulation method for CO2 mineralization and sequestration in saline aquifers is constructed by coupling the Darcy-Brinkman-Stokes (DBS) equation with the advection-diffusion equation (ADE) and incorporating the ion product-solubility product judgment statement. This method involves solving the mass and momentum conservation equations to establish a reaction transport model, dynamically tracking the evolution of flow velocity and pressure fields, and introducing a reaction source term to simulate the mineral dissolution and precipitation process.
It achieves accurate simulation of CO2 saline aquifer mineralization and sequestration process at the pore scale, dynamically tracks dissolution and precipitation processes, simplifies the solution process, reduces research costs, and improves the accuracy of the simulation in terms of spatiotemporal scale and multi-field coupling.
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Abstract
Description
Technical Field
[0001] This invention belongs to the technical field of numerical simulation of CO2 mineralization and storage in saline aquifers, specifically relating to a pore-scale numerical simulation method for CO2 mineralization and storage in saline aquifers that achieves dynamic coupling of dissolution and precipitation. Background Technology
[0002] Global climate change has become one of the core challenges threatening human survival, and excessive emissions of carbon dioxide (CO2), a major greenhouse gas, are a key contributing factor. Against this backdrop, effectively controlling CO2 emissions and promoting the low-carbon transformation of the energy system have become a global research focus and consensus. CO2 capture, utilization, and storage (CCUS) technology, as one of the most effective emission reduction methods currently recognized, can achieve the low-carbon utilization of fossil fuels.
[0003] CO2 geological sequestration is the core component of the CCUS (Chemical Containment System) technology. Its principle involves injecting captured CO2 into deep geological reservoirs using engineering techniques, achieving long-term isolation of CO2 from the atmosphere. Among various geological reservoirs, deep saline aquifers are the most promising CO2 sequestration sites due to their widespread distribution and enormous sequestration capacity (accounting for approximately 98%). The stability and long-term safety of CO2 sequestration in deep saline aquifers are the core prerequisites for the feasibility of sequestration projects, fundamentally depending on the complex physicochemical interactions of the CO2-water-rock multiphase multicomponent system. Among these, mineralization sequestration (also known as chemical sequestration) is the key mechanism for achieving permanent CO2 sequestration—the injected supercritical CO2 reacts with formation water to form an acidic fluid. This acidic fluid then chemically interacts with carbonate and silicate minerals in the reservoir rocks, ultimately transforming CO2 into thermodynamically stable carbonate minerals (such as calcite, dolomite, and ferrodolithite). This process fundamentally avoids the leakage risks that may exist in traditional physical sequestration (structural-stratum sequestration, residual gas sequestration), and the sequestration stability can reach the million-year level, which is the core support for ensuring the long-term safety of sequestration projects. Therefore, thoroughly clarifying the microscopic reaction mechanism, material transport law and multi-field coupling effect in the CO2 saline aquifer mineralization sequestration process is the core prerequisite and key scientific issue for ensuring the safe, efficient and large-scale implementation of sequestration projects.
[0004] However, the CO2 saline aquifer mineralization and storage process involves the coupling of multiple fields, including temperature, seepage, mechanical, and chemical fields (THMC), making the physicochemical process extremely complex. Among them, the dissolution-precipitation of CO2-induced acid and rock minerals directly determines the CO2 storage efficiency. Dissolution increases reservoir porosity and permeability, while precipitation and the migration of its products lead to pore blockage and reduced permeability. The spatiotemporal evolution of the dynamic competition between these two factors is the core contradiction in regulating storage efficiency and long-term reservoir stability.
[0005] Experimental research is a traditional method for revealing the laws governing CO2-water-rock interactions. By constructing a CO2-water-rock reaction system that approximates real reservoir conditions, the mineral dissolution-precipitation process, pore structure evolution characteristics, and changes in fluid geochemical indicators can be directly observed. However, this method has significant limitations: First, the spatiotemporal scales are mismatched. Experimental cycles typically range from tens of days to several years, making it difficult to simulate mineralization and storage processes at the stratigraphic scale (millions to millions of years). Furthermore, the limited size of experimental samples fails to reflect the macroscopic heterogeneity of the reservoir. Second, the cost is high. Simulating high-temperature and high-pressure reservoir conditions requires specialized supercritical CO2 reactors, resulting in extremely high equipment investment and maintenance costs. Third, multi-field coupling is difficult to decouple. In the real reservoir environment, the various fields of THMC are interconnected and mutually influential (for example, increased temperature not only reduces fluid viscosity and increases seepage rate but also accelerates mineral reaction kinetics and alters the rock's elastic modulus and compressive strength). Under experimental conditions, it is difficult to achieve independent control of individual field variables and accurately quantify the contribution weight of each field to the storage process.
[0006] Numerical simulation methods, with their unique advantages in spatiotemporal scale expansion and multi-parameter control, effectively compensate for the shortcomings of experimental research. On the one hand, they can simulate long-term geological evolution processes through scale-up techniques; on the other hand, they can achieve independent control and coupled analysis of various fields in the THMC (Thunderstorm Mechanism) through numerical modeling, enabling rapid multi-parameter sensitivity analysis and significantly shortening the research cycle and reducing research costs. Among them, pore-scale numerical simulation can accurately characterize fluid flow, solute transport, and mineral reaction processes at the microscale based on the real reservoir pore structure. While preserving the heterogeneity of pores, it can conduct systematic sensitivity analysis on microscopic parameters such as pore shape, fluid viscosity, and reaction rate constant, providing direct theoretical support and technical guidance for revealing the microscopic mechanism of CO2 saline aquifer mineralization and storage and optimizing storage engineering design. Summary of the Invention
[0007] The purpose of this invention is to address the aforementioned shortcomings in the prior art by providing a pore-scale numerical simulation method for CO2 mineralization and storage in saline aquifers through dynamic coupling of dissolution and precipitation. This method aims to solve the problems of spatiotemporal scale limitations in experimental research, difficulties in decoupling multi-field coupling, and the large computational load and insufficient accuracy in characterizing microscopic mechanisms in traditional numerical simulation methods.
[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A numerical simulation method for CO2 mineralization and sequestration in saline aquifers at the pore scale, achieving dynamic coupling of dissolution and precipitation, includes the following steps: S1. Drill cores, scan and reconstruct them to obtain real digital cores, and at the same time, sample and analyze the saline water to determine the ionic composition of the saline water. S2. Construct a geometric model at the pore scale based on the real digital core, determine the boundary of the geometric model, and mesh the geometric model. S3. Solve the mass and momentum conservation equations during the CO2 saline aquifer mineralization and storage process to obtain the velocity and pressure distributions of the geometric model in time and space. S4. Based on the velocity and pressure distribution in time and space of the geometric model and the composition of saline water ions, determine the chemical reaction process of CO2 saline water mineralization and storage, and construct a reaction transport model for CO2 saline water mineralization and storage by combining the DBS equation and the ADE equation. S5. Based on the real digital core and saline water ion composition, determine the distribution of soluble minerals, the ion aggregation region in the solution, and the diffusion coefficient in the reaction transport model, and establish the kinetic reaction rate equations for the mineral dissolution process and the mineral precipitation process, as well as the porosity dynamic evolution equation. S6. Introduce the ion product-solubility product judgment statement to solve the reaction transport model, obtain the variation trend of mineral content and distribution and solution ion concentration in the CO2 deep saline aquifer mineralization and storage system, and complete the numerical simulation of reaction transport in CO2 deep saline aquifer mineralization and storage.
[0009] Furthermore, in S3, the mass conservation is as follows:
[0010] The momentum conservation equation is the DBS equation, which is expressed as:
[0011] In the formula, For time, Porosity For fluid density, For flow rate, For pressure, For fluid viscosity, For penetration rate, For Hamiltonian operators.
[0012] Furthermore, in S4, the chemical reaction process includes: The dissolution process involves the reaction of dissolved CO2-induced acid with soluble minerals.
[0013] The process by which ions produced by the dissolution of soluble minerals combine with ions in the saline aquifer to form mineral precipitation:
[0014] In the formula, , These are represented respectively as soluble minerals and precipitated minerals. and These represent the cations and anions produced during the dissolution process, respectively. This refers to the anions that participate in the formation of precipitates in the saline aquifer.
[0015] Furthermore, in S4, the reaction transport model for CO2 mineralization and sequestration in the saline aquifer is an ADE equation with a reaction source term added, which is expressed as:
[0016] In the formula, This represents the molar concentration of solute i in the solution. Indicates the reaction source term. This represents the effective diffusion coefficient of solute i.
[0017] Furthermore, in S5, the kinetic reaction rate equations for the mineral dissolution and precipitation processes are established, and are expressed as follows:
[0018] In the formula, Indicates the reaction rate; Represents the reaction rate constant; This represents the concentration of the substance; c is a constant.
[0019] Furthermore, in S5, the equation set corresponding to the mineral dissolution process is as follows:
[0020]
[0021]
[0022]
[0023] In the formula, Soluble minerals concentration, For the reaction source term of the dissolution process, The concentration of hydrogen ions. is the diffusion coefficient of hydrogen ions. Produced during dissolution The concentration of ions, for The diffusion coefficient of ions, Produced during dissolution The concentration of ions, for The diffusion coefficient of ions.
[0024] Furthermore, in S5, the equation set corresponding to the mineral precipitation process is as follows:
[0025]
[0026]
[0027] In the formula, For the precipitated minerals formed concentration, For the reaction source term of the precipitation process, In solution The concentration of ions, for The diffusion coefficient of ions.
[0028] Furthermore, in S5, the dynamic evolution equation of porosity is expressed as:
[0029] In the formula, and Mineral A and The molar mass.
[0030] Furthermore, in S6, the logic of the ion product-solubility product judgment statement is as follows: when in solution and When the ion product of the precipitate is greater than the solubility product of the precipitated mineral S, a precipitation process is triggered. Solving the equations corresponding to the mineral precipitation process reveals that porosity changes according to the evolution rules of the precipitation process. When the solution contains... and When the ion product is not greater than the solubility product of the precipitated mineral S, the dissolution process is triggered. Solve the equations corresponding to the mineral dissolution process, and the porosity changes according to the evolution rules of the dissolution process.
[0031] Furthermore, in S6, the logic for solving the reaction transport model is as follows: the equations corresponding to the mineral dissolution process, the equations corresponding to the mineral precipitation process, and the porosity dynamic evolution equation are compiled into corresponding solvers. After setting the solution step size and the total solution time, the flow velocity distribution and pressure distribution results in time and space of the geometric model obtained in S3 are combined for iterative solution.
[0032] The numerical simulation method for CO2 mineralization and sequestration at the pore scale in saline aquifers provided by this invention, which achieves dynamic coupling of dissolution and precipitation, has the following beneficial effects: 1. Flow and solute transport system: This invention is based on the Darcy-Brinkman-Stokes (DBS) equation coupled with the advection-diffusion equation (ADE) equation. It considers the solute transport situation while solving the fluid flow. This method dynamically tracks the evolution of the velocity field and pressure field by setting the initial constant flow velocity or pressure difference as the boundary condition.
[0033] 2. Mineral Reaction System: This invention proposes that minerals migrate via an ADE equation with added source terms. The added source terms vary depending on the specific reaction equation, and this method can capture basic reaction kinetics. Multiple source terms can be introduced simultaneously depending on the added reaction.
[0034] 3. Dissolution-Precipitation Coupled System: This invention proposes a method for coupling dissolution and precipitation processes. Since the dissolution and precipitation processes are controlled by different equations, a set of conditional statements is added. When the ion product in the solution is greater than the solubility product of the mineral precipitate, a precipitation reaction occurs, and the equation for the precipitation reaction is solved. Otherwise, a dissolution reaction occurs, and the equation for the dissolution reaction is solved. This method couples the dissolution and precipitation processes, controlled by different equations, into a single process, achieving coupling between the dissolution and precipitation processes.
[0035] 4. This invention achieves numerical simulation of reaction transport at the pore scale by coupling the DBS equation with the ADE equation, simplifying the complex numerical simulation process of reaction transport. In the process of solving reaction transport, the dissolution and precipitation processes are coupled simultaneously, which is closer to the real situation. Moreover, this invention can be run under various working conditions, extracting the solute transport and dissolution-precipitation laws under different conditions, providing support for experimental research. Attached Figure Description
[0036] Figure 1 This is a flowchart of the numerical simulation method for CO2 mineralization and sequestration at the pore scale in saline aquifers, which is based on the dynamic coupling of dissolution and precipitation in the present embodiment.
[0037] Figure 2 This is a schematic diagram of the physical model of the pore scale in the embodiment.
[0038] Figure 3 This is a distribution diagram of soluble minerals in the pore space at 0s in the example.
[0039] Figure 4 This is a distribution diagram of soluble minerals in the pore space at 4s in the example.
[0040] Figure 5 For example, SO4 at 0s 2- Distribution diagram in the pore space.
[0041] Figure 6This is a distribution diagram of CaSO4 in the pore space at 4s in the example.
[0042] Figure 7 The graph shows the change in soluble mineral concentration over time after normalization in the examples.
[0043] Figure 8 The graph shows the change in the concentration of precipitated minerals over time after normalization treatment in the examples.
[0044] Figure 9 This is a comparison chart of the permeability changes over time in the dissolution process and the dissolution-coupled precipitation process in the examples. Detailed Implementation
[0045] The specific embodiments of the present invention are described below to enable those skilled in the art to understand the present invention. However, it should be understood that the present invention is not limited to the scope of the specific embodiments. For those skilled in the art, various changes are obvious as long as they are within the spirit and scope of the present invention as defined and determined by the appended claims. All inventions utilizing the concept of the present invention are protected.
[0046] This embodiment presents a numerical simulation method for the pore-scale CO2 mineralization and sequestration of saline aquifers through dynamic coupling of dissolution and precipitation, referencing... Figure 1 Specifically, it includes the following: S1. Core samples were drilled, scanned, and reconstructed to obtain a true digital core. Simultaneously, saline water samples were taken and analyzed to determine the saline water ionic composition (Na). + Cl - H + SO4 2- HCO3 - ); S2. Based on real digital cores, construct a geometric model at the pore scale, determine the left boundary of the model as the velocity inlet, inject acid at a constant velocity, and the right boundary as the pressure outlet, and determine the boundary of the geometric model, while meshing the geometric model. In one specific embodiment, such as Figure 2 As shown, to ensure the accuracy of the numerical simulation, the mesh in the pore region should have sufficient resolution. The left boundary of the model is set as the velocity inlet, and the inlet injection rate is set to a constant 1e-1. -4 m / s, set the right boundary of the model as the pressure outlet, and set the outlet pressure to 0pa.
[0047] S3. Solve the mass and momentum conservation equations during the CO2 saline aquifer mineralization and storage process to obtain the velocity and pressure distributions of the geometric model in time and space. The law of conservation of mass is:
[0048] The momentum conservation equation is the DBS equation, which is expressed as:
[0049] In the formula, For time, Porosity For fluid density, For flow rate, For pressure, For fluid viscosity, For penetration rate, For Hamiltonian operators.
[0050] S4. Based on the velocity and pressure distribution in time and space of the geometric model and the composition of saline water ions, determine the chemical reaction process of CO2 saline water mineralization and storage, and construct a reaction transport model for CO2 saline water mineralization and storage by combining the DBS equation and the ADE equation. Among them, the chemical reactions involved in the mineralization and sequestration of CO2 saline aquifers are determined as follows: the chemical reaction processes involved in the mineralization and sequestration of CO2 saline aquifers are the dissolution process in which the acid induced by dissolved CO2 reacts with soluble minerals, and the precipitation process in which the ions generated by the dissolution of soluble minerals combine with ions in the saline aquifer to form minerals. The chemical equation expressions are as follows: The dissolution process involves the reaction of dissolved CO2-induced acid with soluble minerals.
[0051] In one specific embodiment, the specific chemical reaction equation for the dissolution process is as follows:
[0052] The process by which ions produced by the dissolution of soluble minerals combine with ions in the saline aquifer to form mineral precipitation:
[0053] In the formula, , These are represented respectively as soluble minerals and precipitated minerals. and These represent the cations and anions produced during the dissolution process, respectively. This refers to the anions that participate in the formation of precipitates in the saline aquifer.
[0054] In one specific embodiment, the specific chemical reaction equation for the c precipitation process is as follows:
[0055] The reaction transport model for CO2 mineralization and sequestration in saline aquifers is the ADE equation with a reaction source term added, which is expressed as:
[0056] In the formula, This represents the molar concentration of solute i in the solution. Indicates the reaction source term. This represents the effective diffusion coefficient of solute i. When it is a consumable, the equation is reduced by the reaction source term. When it is a product, the equation adds a reaction source term. .
[0057] S5. Based on real digital core samples and saline water ion composition, determine the distribution of soluble minerals, the ion aggregation region in the solution, and the diffusion coefficient in the reaction transport model, and establish the kinetic reaction rate equations for mineral dissolution and mineral precipitation processes, as well as the dynamic evolution equation for porosity. Establish kinetic reaction rate equations for mineral dissolution and precipitation processes: determine the reactants and products in the reaction system and their corresponding equilibrium constants; construct a chemical reaction database for the mineralization and sequestration reaction and migration processes of CO2 saline aquifers; and use this database to calculate numerical simulations of the reaction and migration of various species. The expression for the reaction rate is:
[0058] In the formula, Represents reaction rate (mol / m 3 s); Represents the reaction rate constant (s) -1 ), which only changes with temperature; Indicates the concentration of a substance (mol / m³) 3 c is a constant.
[0059] In one specific embodiment, the set of equations corresponding to the mineral dissolution process is as follows:
[0060]
[0061]
[0062]
[0063] In the formula, for concentration, For the reaction source term of the dissolution process, The concentration of hydrogen ions. is the diffusion coefficient of hydrogen ions. for concentration, for diffusion coefficient, for concentration, for The diffusion coefficient; in = ; The specific surface area of a mineral is expressed as follows: , It is a constant; The specific chemical reaction equation for the precipitation process is as follows:
[0064] The equations corresponding to the mineral precipitation process are:
[0065]
[0066]
[0067] In the formula, for The concentration; For the reaction source term of the precipitation process, for The concentration.
[0068] in The expression is:
[0069] In the formula, It follows a normal distribution.
[0070] Porosity dynamic evolution equation; during the dissolution process, The value increases as the amount of soluble minerals decreases; however, during precipitation... The value decreases with the increase of precipitated minerals; therefore, during the dissolution and precipitation process, They are governed by two different equations, specifically:
[0071] In the formula, and These are the molar masses of CaCO3 and CaSO4, respectively.
[0072] S6. Introduce the ion product-solubility product judgment statement, solve the reaction transport model, obtain the variation trend of mineral content and distribution and solution ion concentration in the CO2 deep saline water mineralization and storage system, and complete the numerical simulation of CO2 deep saline water mineralization and storage reaction transport. The logic of the ion product-solubility product judgment statement is as follows: when in solution and When the ion product of the precipitate is greater than the solubility product of the precipitated mineral S, a precipitation process is triggered. Solving the equations corresponding to the mineral precipitation process reveals that porosity changes according to the evolution rules of the precipitation process. When the solution contains... and When the ion product is not greater than the solubility product of the precipitated mineral S, the dissolution process is triggered. Solve the equations corresponding to the mineral dissolution process, and the porosity changes according to the evolution rules of the dissolution process. In other words, to simultaneously couple the dissolution and precipitation processes, this embodiment introduces a set of conditional statements: when the ion product of calcium ions and sulfate ions in the solution is greater than the solubility product of calcium sulfate precipitate, ;otherwise, .
[0073] In some embodiments, the minerals used in the dissolution process can be replaced by other types of minerals such as magnesium olivine (Mg2SiO4), iron olivine (Fe2SiO4), potassium feldspar (KAlSi3O8), and sodium feldspar (NaAlSi3O8); the minerals used in the precipitation process can be replaced by dolomite (CaMg(CO3)2).
[0074] The logic for solving the reaction transport model is as follows: the equations corresponding to the mineral dissolution process, the equations corresponding to the mineral precipitation process, and the porosity dynamic evolution equation are compiled into corresponding solvers. After setting the solution step size and the total solution time, the flow velocity distribution and pressure distribution results in time and space of the geometric model obtained in S3 are combined for iterative solution.
[0075] In one specific embodiment, mineral distribution and grid location are determined based on the digital core data obtained from scanning. Na is set. + Cl - H + SO4 2- HCO3 - The diffusion coefficient is 1e -9 m 2 / s, based on the determined grid position of the mineral, are defined as soluble minerals CaCO3 and SO4, respectively. 2- The initial concentration of ions, soluble mineral CaCO3 was set at 1 mol / L, and SO42- 2-The initial ion concentration was set to 0.5 mol / L, and the injected acid concentration was 0.1 mol / L. During precipitation, when the CaSO4 concentration was greater than 0.3 mol / L, the CaSO4 concentration was kept constant at 0.3 mol / L. =1e -4 At this point, 0.3 mol / L is defined as the precipitation threshold, and CaSO4 is defined as a non-flowing solid.
[0076] In one specific embodiment, the mass conservation equation and the DBS equation are first compiled. Then, the equations corresponding to the mineral dissolution process are compiled to solve the dissolution process, and the equations corresponding to the mineral precipitation process are compiled to solve the precipitation process. Finally, the porosity dynamic evolution equation is compiled. The output step size is set to deltaT=0.00001s and endTime=5s for iterative solution. After the solver finishes running, the flow rate distribution, pressure distribution, and concentration distribution of each component at each time step are exported. The results are analyzed using visualization software to obtain the distribution maps of soluble minerals in the pore space at 0s and 4s, as shown below. Figure 3 and Figure 4 As shown; and SO4 at 0s 2- Distribution diagrams of CaSO4 in the pore space and at 4s, as shown below. Figure 5 and Figure 6 As shown in the figure, the changes in the concentrations of soluble minerals and precipitable minerals over time after normalization are statistically analyzed. Figure 7 and Figure 8 As shown. The permeability change over time considering the dynamic coupling process of dissolution and precipitation is as follows: Figure 9 As shown.
[0077] Although specific embodiments of the invention have been described in detail with reference to the accompanying drawings, this should not be construed as limiting the scope of protection of this patent. Various modifications and variations that can be made by a person skilled in the art without inventive effort within the scope described in the claims still fall within the scope of protection of this patent.
Claims
1. A numerical simulation method for CO2 mineralization and sequestration at the pore scale in saline aquifers, achieving dynamic coupling of dissolution and precipitation, characterized in that, Includes the following steps: S1. Drill cores, scan and reconstruct them to obtain real digital cores, and at the same time, sample and analyze the saline water to determine the ionic composition of the saline water. S2. Construct a geometric model at the pore scale based on the real digital core, determine the boundary of the geometric model, and mesh the geometric model. S3. Solve the mass and momentum conservation equations during the CO2 saline aquifer mineralization and storage process to obtain the velocity and pressure distributions of the geometric model in time and space. S4. Based on the velocity and pressure distribution in time and space of the geometric model and the composition of saline water ions, determine the chemical reaction process of CO2 saline water mineralization and storage, and construct a reaction transport model for CO2 saline water mineralization and storage by combining the DBS equation and the ADE equation. S5. Based on the real digital core and saline water ion composition, determine the distribution of soluble minerals, the ion aggregation region in the solution, and the diffusion coefficient in the reaction transport model, and establish the kinetic reaction rate equations for the mineral dissolution process and the mineral precipitation process, as well as the porosity dynamic evolution equation. S6. Introduce the ion product-solubility product judgment statement to solve the reaction transport model, obtain the variation trend of mineral content and distribution and solution ion concentration in the CO2 deep saline aquifer mineralization and storage system, and complete the numerical simulation of reaction transport in CO2 deep saline aquifer mineralization and storage.
2. The numerical simulation method for CO2 mineralization and sequestration at the pore scale in saline aquifers based on dynamic coupling of dissolution and precipitation, as described in claim 1, is characterized in that... In S3, the mass conservation law is as follows: The momentum conservation equation is the DBS equation, which is expressed as: In the formula, For time, Porosity For fluid density, For flow rate, For pressure, For fluid viscosity, For penetration rate, For Hamiltonian operators.
3. The numerical simulation method for CO2 mineralization and sequestration at the pore scale in saline aquifers based on dynamic coupling of dissolution and precipitation, as described in claim 1, is characterized in that... In S4, the chemical reaction process includes: The dissolution process involves the reaction of dissolved CO2-induced acid with soluble minerals. The process by which ions produced by the dissolution of soluble minerals combine with ions in the saline aquifer to form mineral precipitation: In the formula, , These are represented respectively as soluble minerals and precipitated minerals. and These represent the cations and anions produced during the dissolution process, respectively. This represents hydrogen ions in the solution. This refers to the anions that participate in the formation of precipitates in the saline aquifer.
4. The numerical simulation method for CO2 mineralization and sequestration at the pore scale in saline aquifers based on dynamic coupling of dissolution and precipitation, as described in claim 2, is characterized in that... In S4, the reaction transport model for CO2 mineralization and sequestration in the saline aquifer is an ADE equation with a reaction source term added, which is expressed as: In the formula, This represents the molar concentration of solute i in the solution. Indicates the reaction source term. This represents the effective diffusion coefficient of solute i.
5. The numerical simulation method for CO2 mineralization and sequestration at the pore scale in saline aquifers based on dynamic coupling of dissolution and precipitation, as described in claim 4, is characterized in that... In S5, the kinetic reaction rate equations for the mineral dissolution and precipitation processes are established, and are expressed as follows: In the formula, Indicates the reaction rate; Represents the reaction rate constant; This represents the concentration of the substance; c is a constant.
6. The numerical simulation method for CO2 mineralization and sequestration at the pore scale in saline aquifers based on dynamic coupling of dissolution and precipitation, as described in claim 5, is characterized in that... In S5, the equation set corresponding to the mineral dissolution process is as follows: In the formula, Soluble minerals concentration, For the reaction source term of the dissolution process, The concentration of hydrogen ions. is the diffusion coefficient of hydrogen ions. Produced during dissolution The concentration of ions, for The diffusion coefficient of ions, Produced during dissolution The concentration of ions, for The diffusion coefficient of ions.
7. The numerical simulation method for CO2 mineralization and sequestration at the pore scale in saline aquifers based on dynamic coupling of dissolution and precipitation, as described in claim 6, is characterized in that... In S5, the equation set corresponding to the mineral precipitation process is as follows: In the formula, For the precipitated minerals formed concentration, For the reaction source term of the precipitation process, In solution The concentration of ions, for The diffusion coefficient of ions.
8. The numerical simulation method for CO2 mineralization and sequestration at the pore scale in saline aquifers based on dynamic coupling of dissolution and precipitation, as described in claim 7, is characterized in that... In S5, the dynamic evolution equation of porosity is expressed as follows: In the formula, and Mineral A and The molar mass.
9. The numerical simulation method for CO2 mineralization and sequestration at the pore scale in saline aquifers based on dynamic coupling of dissolution and precipitation, as described in claim 3, is characterized in that... In S6, the logic of the ion product-solubility product judgment statement is as follows: when in solution and When the ion product of the precipitate is greater than the solubility product of the precipitated mineral S, a precipitation process is triggered. Solving the equations corresponding to the mineral precipitation process reveals that porosity changes according to the evolution rules of the precipitation process. When the solution contains... and When the ion product is not greater than the solubility product of the precipitated mineral S, the dissolution process is triggered. Solve the equations corresponding to the mineral dissolution process, and the porosity changes according to the evolution rules of the dissolution process.
10. The numerical simulation method for CO2 mineralization and sequestration at the pore scale in saline aquifers based on dynamic coupling of dissolution and precipitation as described in claim 1, characterized in that, In S6, the logic for solving the reaction transport model is as follows: the equations corresponding to the mineral dissolution process, the equations corresponding to the mineral precipitation process, and the porosity dynamic evolution equation are compiled into corresponding solvers. After setting the solution step size and the total solution time, the flow velocity distribution and pressure distribution results in time and space of the geometric model obtained in S3 are combined to perform iterative solution.