Scale upgrading method of carbon dioxide salt water layer storage model

Abstract

The invention relates to a scale upgrading method for a carbon dioxide salt water layer storage model, which comprises the following steps: carrying out coarse scale characterization on a fine scale model control equation to obtain a coarse scale control equation; performing scale upgrading calculation on the scale parameter to obtain an upscaling parameter; and substituting the upscaling parameter into the coarse scale control equation to carry out numerical simulation. According to the precise scale upgrading method for the CO2 salt water layer storage model, the coarse scale model obtained through scale upgrading can obviously improve the numerical reservoir simulation efficiency on the premise that the accuracy is kept.

Description

Technical Field

[0001] The present invention relates to the technical field of underground reservoir modeling and numerical simulation, and in particular to a scale-up method for a carbon dioxide saline aquifer storage model. Background Art

[0002] Carbon capture and storage (CCS) technology is an important way to reduce CO2 emissions. Among them, saline aquifers have become one of the preferred locations for CO2 geological storage due to their wide distribution, suitable burial depth and great storage potential. In order to accurately reflect the heterogeneity of the strata, it is crucial to construct a fine geological model for reservoir description. However, a large and fine geological model may contain hundreds of millions of grids, and its numerical simulation requires extremely high computing resources and time costs. Therefore, it is of great significance to study effective upscaling methods. Upscaling is to convert a fine-scale geological model with a large number of grids into a coarse-scale numerical simulation model with a small number of grids while retaining the key information of the fine-scale model as much as possible, thereby significantly improving the efficiency of numerical simulation and reducing the demand for computing resources.

[0003] Currently, there are relatively limited studies on the upscaling of carbon storage models. Most existing studies are based on the idea of ​​"average" and use analytical methods for upscaling. Although this method is simple to calculate, it is insufficient in terms of accuracy. In addition, existing studies usually only consider the upscaling of single-phase flow (such as parameters such as permeability and porosity), or use simplified black oil models, which do not fully reflect the complex interaction between CO2 and water (such as the dissolution effect of CO2 in water).

[0004] Therefore, there is an urgent need in this field for a numerical scaling method suitable for carbon dioxide saline aquifer storage. Summary of the invention

[0005] The present invention provides a scale-up method for a carbon dioxide saline layer storage model, so as to solve the defects of the prior art.

[0006] The present invention provides a method for scaling up a carbon dioxide saline aquifer storage model, comprising:

[0007] S1: Perform coarse-scale characterization on the fine-scale model control equation to obtain the coarse-scale control equation;

[0008] S2: perform upscaling calculation on the scale parameter to obtain the upscaling parameter;

[0009] S3: Substituting the upscaling parameters into the coarse-scale control equations to perform numerical simulation.

[0010] According to a method for scaling up a carbon dioxide saline layer storage model provided by the present invention, step S1 further comprises:

[0011] S111: Establish fine-scale model control equations;

[0012] S112: Perform a coarse-scale characterization on the control equation of the fine-scale model to obtain a coarse-scale control equation.

[0013] According to a scale-up method of a carbon dioxide saline aquifer storage model provided by the present invention, the fine-scale model control equation in step S111 specifically includes:

[0014] A fine-scale well model, wherein the fine-scale well model expression is:

[0015]

[0016] in, is the flow rate of the well, WI is the well index, p i is the grid pressure of grid i in the fine-scale well model, is the bottom hole pressure of grid i in the fine-scale well model;

[0017] The fine-scale two-phase flow control equation is expressed as follows:

[0018]

[0019] Among them, α is the component index value, M α is the mass accumulation of component α in all phases, F α is the mass flux, q α is the flow rate of component α, and t is the time.

[0020] According to a scale-up method for a carbon dioxide saline aquifer storage model provided by the present invention, the coarse-scale control equation in step S1 includes a coarse-scale single-phase flow control equation and a coarse-scale two-phase flow control equation.

[0021] According to a scale-up method of a carbon dioxide saline aquifer storage model provided by the present invention, in step S1, the step of obtaining a coarse-scale single-phase flow control equation specifically includes:

[0022] S121: Define Darcy's law for single-phase flow;

[0023] S122: establishing a fine-scale single-phase flow control equation according to the single-phase flow Darcy's law and the mass conservation equation;

[0024] S123: Replace the fine-scale parameters in the fine-scale single-phase flow control equation with coarse-scale parameters to obtain the coarse-scale single-phase flow control equation.

[0025] According to a scaling method for a carbon dioxide saline layer storage model provided by the present invention, the expression of the single-phase flow Darcy's law in step S121 is:

[0026]

[0027] Among them, u is Darcy velocity, K is permeability tensor, p is pressure, μ is viscosity, ρ is density, and g is gravitational acceleration vector;

[0028] The expression of the mass conservation equation in step S122 is:

[0029]

[0030] Where t is time, φ is porosity, is the source-sink term;

[0031] The expression of the fine-scale single-phase flow control equation in step S122 is:

[0032]

[0033] in, is the volume flow rate;

[0034] The expression of the coarse-scale single-phase flow control equation in step S123 is:

[0035]

[0036] Among them, K * is the permeability tensor under the coarse-scale model, μ c is the viscosity under the coarse-scale model, p c is the pressure in the coarse-scale model, ρ c is the density under the coarse-scale model.

[0037] According to a scaling method for a carbon dioxide saline layer storage model provided by the present invention, the scaling parameters in step S2 include:

[0038] One-way flow scale-up parameters, wherein the one-way flow scale-up parameters include scale-up well index and scale-up conductivity;

[0039] Two-phase flow scale-up parameters, wherein the two-phase flow scale-up parameters include a scaled capillary force curve and a scaled relative permeability curve.

[0040] According to a scaling method for a carbon dioxide saline layer storage model provided by the present invention, the step of obtaining the scaling well index further comprises:

[0041] S211: Solve the fine-scale single-phase flow control equations at the global scale to obtain fine-scale grid pressure and fine-scale grid flow solutions;

[0042] S212: Obtaining an upscaled well index by calculating the fine-scale grid pressure and the fine-scale grid flow solution;

[0043] The step of obtaining the upscaled conductivity further comprises:

[0044] S221: Obtaining upscaled conductivity by calculating the fine-scale grid pressure and the fine-scale grid flow solution;

[0045] The step of obtaining the upscaled capillary force curve further comprises:

[0046] S231: performing coarse grid division on the fine-scale model, and extracting the capillary force curve data of all fine grids inside each coarse grid;

[0047] S232: Preset a plurality of capillary force values ​​in the selected target coarse grid, and calculate the coarse grid gas saturation of the target coarse grid according to the preset capillary force values ​​and the fine grid gas saturation of each fine grid in the target coarse grid;

[0048] S233: calculating and obtaining an upscaled capillary force curve of a target coarse grid according to different coarse grid gas saturations corresponding to different preset capillary force values;

[0049] The step of obtaining the upscaled relative permeability further comprises:

[0050] S241: Perform two-phase flow numerical simulation on a global scale to obtain numerical simulation results;

[0051] S242: Calculate the upscaled relative permeability through the numerical simulation results.

[0052] According to a scaling method for a carbon dioxide saline layer storage model provided by the present invention, the expression of the scaling well index in step S212 is:

[0053]

[0054] Among them, i is the coarse-scale well grid index value, l is the fine-scale well grid index value, is the upscaled well index of the coarse-scale well grid i, is the well flow rate in the fine-scale well grid l, <p f > i is the volume average of all fine grid pressures in the coarse-scale well grid i, represents the volume average of all fine-scale well pressures in the coarse-scale well grid i;

[0055] The expression of the upscaled conductivity in step S221 is:

[0056]

[0057] in, represents the coarse-scale interface between coarse grids i and i+1, T * To calculate the upscaling conductivity, is the sum of the fine grid flow at the coarse-scale interface, <p f > i is the volume average of the fine grid pressure in the coarse grid i, is the volume average of the fine grid pressure in the coarse grid i+1, ρ is the density, g is the gravitational acceleration, ΔD c is the depth difference between coarse grids i and i+1;

[0058] The expression of the upscaled relative permeability in step S242 is:

[0059]

[0060] in, is the upscale gas relative permeability, is the upscaled water relative permeability, is the coarse-scale viscosity of the gas phase, is the coarse-scale viscosity of the water phase, is the sum of the gas phase flow rates of the fine grid at the coarse-scale interface, is the sum of the water phase flow rates of the fine grids at the coarse-scale interface, is the upscaled capillary force of the coarse grid i, is the upscaled capillary force of the coarse grid i+1, is the coarse-scale gas density, is the coarse-scale water phase density.

[0061] According to a scaling method for a carbon dioxide saline aquifer storage model provided by the present invention, in step S2, when any parameter in the scaling parameters has an abnormal value, the abnormal value is replaced by a corresponding replacement value.

[0062] The present invention also provides a numerical simulation method for a scale-upgraded carbon dioxide saline aquifer storage model, comprising: performing a carbon cycle simulation on a coarse-scale model after scale-up based on any of the scale-upgrading methods for a carbon dioxide saline aquifer storage model described above to obtain a simulation result.

[0063] The present invention provides a scale-up method for a carbon dioxide saline aquifer storage model. Firstly, by upgrading from a fine-scale model to a coarse-scale model, the number and complexity of grids required for calculation are greatly reduced, thereby significantly improving the calculation efficiency, which is crucial for large-scale carbon storage simulation and prediction, and helps to obtain results faster and support the decision-making process; secondly, the present invention uses a systematic scale-up method, including constructing fine-scale control equations, constructing coarse-scale control equations based on fine-scale control equations, and performing scale-up calculations on key parameters to obtain scale-up parameters, to ensure that the coarse-scale model is as consistent as possible with the fine-scale model in terms of major physical processes, thereby significantly improving the accuracy of the coarse-scale model. , providing a reliable basis for the evaluation of carbon sequestration effects; secondly, by providing a complete scale-up method and steps, including the calculation of the scale-up well index, scale-up conductivity, scale-up capillary force curve and scale-up relative permeability curve, the present invention improves the flexibility of carbon sequestration models in simulation at different scales, enhances the practicality and applicability of the model, and provides strong support for promoting the widespread application of carbon sequestration technology; in addition, in the scale-up process, the present invention also considers the processing of outliers. When any parameter in the scale-up parameters has an outlier, replacing the outlier with the corresponding fine-scale parameter helps to ensure the stability and reliability of the model and avoid distortion of simulation results caused by abnormal parameters. In general, the present invention provides an efficient, accurate, practical and robust global scale-up method for carbon sequestration models, which provides strong support for the simulation, prediction and optimization of carbon sequestration technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0065] Figure 1 A schematic flow chart of a method for scaling up a carbon dioxide saline layer storage model provided in an embodiment of the present invention;

[0066] Figure 2 A schematic diagram of the permeability field of a fine-scale oblique river channel model provided in an embodiment of the present invention;

[0067] Figure 3 A schematic diagram comparing fine-scale numerical simulation results and coarse-scale numerical simulation results provided by an embodiment of the present invention;

[0068] Figure 4 A schematic diagram for comparing the gas saturation field of a fine scale and a gas saturation field of a coarse scale model when PVI=0.25 provided in an embodiment of the present invention;

[0069] Figure 5 A schematic diagram for comparing the fine-scale gas saturation field and the coarse-scale model gas saturation field when PVI=0.7 provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0070] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings in the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments, and they should not be understood as limitations on the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. In the description of the present invention, it should be understood that the terms used are only for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0071] like Figure 1 As shown, the present invention provides a scale-up method for a carbon dioxide saline aquifer storage model, comprising:

[0072] S1: Perform coarse-scale characterization on the fine-scale model control equation to obtain the coarse-scale control equation.

[0073] Furthermore, the present invention takes well drive conditions into consideration and needs to study a scale upgrade method for the well model. In step S1, the Peaceman well model is first used to describe the fine-scale well model, and then the coarse-scale well flow equation is obtained by replacing the fine-scale parameters in the well flow equation with coarse-scale parameters.

[0074] Wherein, step S1 further comprises:

[0075] S111: Establish fine-scale model control equations.

[0076] S112: Perform a coarse-scale characterization on the control equation of the fine-scale model to obtain a coarse-scale control equation.

[0077] In the process of upscaling the carbon sequestration model, it is first necessary to establish a fine-scale well model, which is used to describe the relationship between the well flow rate and the surrounding grid pressure at a fine scale (i.e., high resolution). In this step, the Peaceman well model is selected as the fine-scale well model.

[0078] The fine-scale model control equation in step S111 specifically includes:

[0079] A fine-scale well model, wherein the fine-scale well model expression is:

[0080]

[0081] in, is the flow rate of the well, WI is the well index, p i is the grid pressure of grid i in the fine-scale well model, is the bottom hole pressure of grid i in the fine-scale well model;

[0082] The fine-scale two-phase flow control equation is expressed as follows:

[0083]

[0084] Among them, α is the component index value, M α is the mass accumulation of component α in all phases, F α is the mass flux, q α is the flow rate of component α, and t is the time.

[0085] Wherein, the coarse-scale control equation in step S1 includes a coarse-scale single-phase flow control equation and a coarse-scale two-phase flow control equation.

[0086] Among them, in step S1, the step of obtaining the coarse-scale single-phase flow control equation specifically includes:

[0087] S121: Define Darcy's law for single-phase flow.

[0088] The expression of the single-phase flow Darcy's law in step S121 is:

[0089]

[0090] Where u is the Darcy velocity, K is the permeability tensor, p is the pressure, μ is the viscosity, ρ is the density, and g is the gravitational acceleration vector.

[0091] S122: According to the single-phase flow Darcy's law and the mass conservation equation, a fine-scale single-phase flow control equation is established.

[0092] The expression of the mass conservation equation in step S122 is:

[0093]

[0094] Where t is time, φ is porosity, It is a source-sink term.

[0095] The expression of the fine-scale single-phase flow control equation in step S122 is:

[0096]

[0097] in, is the volume flow rate.

[0098] S123: Replace the fine-scale parameters in the fine-scale single-phase flow control equation with coarse-scale parameters to obtain the coarse-scale single-phase flow control equation.

[0099] The expression of the coarse-scale single-phase flow control equation in step S123 is:

[0100]

[0101] Among them, K * is the permeability tensor under the coarse-scale model, μ c is the viscosity under the coarse-scale model, p c is the pressure in the coarse-scale model, ρ c is the density under the coarse-scale model.

[0102] Furthermore, in steps S121 to S123, the single-phase flow Darcy's law and the mass conservation equation are first combined to obtain the following expression:

[0103]

[0104] Since the single-phase flow problem is relatively simple, the changes in porosity and fluid density over time are usually not considered. The above formula can be simplified to obtain the fine-scale single-phase flow control equation in step S122. Since the coarse-scale control equation of the single-phase flow used in this patent has the same structure as the fine-scale control equation, it is only necessary to replace the fine-scale parameters with the coarse-scale parameters to obtain the coarse-scale control equation in step S123.

[0105] As for the control equation of two-phase flow, the fine-scale two-phase flow control equation of the CO2-water full physical model can be expressed as:

[0106]

[0107] In the formula, represents the mass accumulation of component α in all phases j, φ is the porosity, S j is the saturation of phase j, ρ j is the density of phase j, is the mass fraction of component α in phase j, F α is the mass flux, which describes the mass transfer of component α due to flow, diffusion and other effects. The mass transfer caused by fluid flow can be expressed as F j is the flux of phase j,

[0108] The coarse-scale control equation of two-phase flow replaces the parameters of the fine-scale control equation with coarse-scale parameters, among which the well index, permeability (or conductivity), capillary force curve and relative permeability curve are calculated by the scale-up algorithm. The actual numerical simulation process is carried out through the CO2STORE module in the Schlumberger Eclipse-E300 component simulator.

[0109] S2: Perform upscaling calculation on the scale parameter to obtain the upscaling parameter.

[0110] The upscaling parameters in step S2 include:

[0111] One-way flow scaling parameters, wherein the one-way flow scaling parameters include scaling well index and scaling conductivity.

[0112] The step of obtaining the upscaled well index further comprises:

[0113] S211: Solve the fine-scale single-phase flow control equations at the global scale to obtain fine-scale grid pressure and fine-scale grid flow solutions.

[0114] S212: Obtaining an upscaled well index by calculating the fine-scale grid pressure and the fine-scale grid flow solution.

[0115] The global well index scale upgrade requires solving the fine-scale single-phase flow control equation at the global scale in advance to obtain the pressure and flow solutions of the fine-scale grid, and then using the fine-scale pressure and flow solution data to calculate the scaled well index WI * , that is, the upscaling well index calculation formula can be obtained as shown below.

[0116] The expression of the upscaled well index in step S212 is:

[0117]

[0118] Among them, i is the coarse-scale well grid index value, l is the fine-scale well grid index value, is the upscaled well index of the coarse-scale well grid i, is the well flow rate in the fine-scale well grid l, <p f > i is the volume average of all fine grid pressures in the coarse-scale well grid i, It represents the volume average of the pressures of all fine-scale wells in the coarse-scale well grid i.

[0119] The step of obtaining the upscaled conductivity further comprises:

[0120] S221: Obtaining upscaled conductivity by calculating the fine-scale grid pressure and the fine-scale grid flow solution.

[0121] The expression of the upscaled conductivity in step S221 is:

[0122]

[0123] in, represents the coarse-scale interface between coarse grids i and i+1, T * To calculate the upscaling conductivity, is the sum of the fine grid flow at the coarse-scale interface, <p f > i is the volume average of the fine grid pressure in the coarse grid i, <p f > i+1 is the volume average of the fine grid pressure in the coarse grid i+1, ρ is the density, g is the gravitational acceleration, ΔD c is the depth difference between coarse grids i and i+1.

[0124] For global permeability upscaling, it is necessary to first perform global fine-scale single-phase flow numerical simulation to obtain fine-scale grid pressure and flow, and then use the listed calculation to obtain the upscaled conductivity T * That's it.

[0125] Two-phase flow scale-up parameters, wherein the two-phase flow scale-up parameters include a scaled capillary force curve and a scaled relative permeability curve.

[0126] The step of obtaining the upscaled capillary force curve further comprises:

[0127] S231: Coarsely mesh the fine-scale model and extract the capillary force curve data of all fine meshes inside each coarse mesh.

[0128] S232: Preset a plurality of capillary force values ​​in the selected target coarse grid, and calculate the coarse grid gas saturation of the target coarse grid according to the preset capillary force values ​​and the fine grid gas saturation of each fine grid in the target coarse grid.

[0129] S233: Calculate and obtain an upscaled capillary force curve of a target coarse grid according to different coarse grid gas saturations corresponding to different preset capillary force values.

[0130] The present invention uses the capillary limit method to scale up the capillary force curve. The specific operation process is described as follows. First, the fine-scale model is divided into coarse grids, and the capillary force curve data of each fine grid inside each coarse grid are extracted one by one; within the target coarse grid, a reasonable capillary force value P is set. c Each fine grid has a corresponding gas saturation S g Using these fine grids, S g The gas saturation of the coarse grid is calculated by The calculation formula is as follows:

[0131]

[0132] Where N f is the number of fine grids in the coarse grid, φ i is the porosity of the ith fine grid, V i is the volume of the i-th fine grid, S g,i (P c ) is the capillary force P c The gas saturation of the i-th fine grid at time .

[0133] The following will As the up-scale capillary force curve A data point on the surface of the capillary force P is continuously selected within a reasonable range. c , repeat the above steps to obtain the upscaled capillary force curve of the target coarse grid; secondly, perform the above steps on all coarse grids in the model, and finally obtain the upscaled capillary force curve of each coarse grid in the entire coarse-scale model.

[0134] The step of obtaining the upscaled relative permeability further comprises:

[0135] S241: Perform two-phase flow numerical simulation on a global scale to obtain numerical simulation results.

[0136] S242: Calculate the upscaled relative permeability through the numerical simulation results.

[0137] Since the Eclipse commercial numerical simulation software used in numerical simulation can only accept the relative permeability of the grid, and the upscaled relative permeability calculated by the upscaling method of the present invention is defined on the coarse-scale interface, during the processing, it is necessary to assign the upscaled relative permeability calculated on the coarse-scale interface to the coarse grid upstream of the flow.

[0138] The expression of the upscaled relative permeability in step S242 is:

[0139]

[0140] in, is the upscale gas relative permeability, is the upscaled water relative permeability, is the coarse-scale viscosity of the gas phase, is the coarse-scale viscosity of the water phase, is the sum of the gas phase flow rates of the fine grid at the coarse-scale interface, is the sum of the water phase flow rates of the fine grids at the coarse-scale interface, is the upscaled capillary force of the coarse grid i, is the upscaled capillary force of the coarse grid i+1, is the coarse-scale gas density, is the coarse-scale water phase density.

[0141] In addition, if the model contains production wells, considering that the two-phase flow behavior of the grid where the production wells are located will be strongly disturbed by the wells, it is necessary to calculate the upscaled relative permeability of the production well grid separately. The calculation formula is as follows:

[0142]

[0143] In the formula, and are the gas and water phase flow rates of the well, respectively.

[0144] In previous studies on the upscaling of relative permeability numerical methods, the numerical simulation results of the original fine-scale model were usually used directly to calculate the upscaled relative permeability. However, the full physical model used in the present invention takes into account the solubility of CO2 in water. Studies have found that solubility has a significant impact on fluid flow, which in turn leads to large errors in the calculation of upscaled relative permeability. Therefore, the present invention innovatively proposes a simplified model upscaling and upscaling strategy for full physical model numerical simulation. This strategy introduces a simplified fine-scale model, in which the solubility of CO2 in water is shielded, and other parameters remain the same as those of the full physical model. First, run the numerical simulation of the simplified fine-scale model; then, use the simulation results of the simplified model to calculate the upscaled relative permeability; finally, input it into the coarse-scale full physical model for numerical simulation, and compare it with the simulation results of the fine-scale full physical model.

[0145] In step S2, when any parameter in the scale-up parameters has an abnormal value, the abnormal value is replaced by a corresponding replacement value.

[0146] For the upscaling well index, if WI * If it is an abnormal value (such as infinite value, Nan, abnormal 0 value or negative value, etc.), the coarse-scale permeability of the coarse grid where the wellbore is located is calculated by the geometric mean method, and the fine-scale well index WI calculation formula is used to obtain WI (K * )Replace the abnormal WI * , the specific WI calculation formula is:

[0147]

[0148] Where WI is the calculated fine-scale well index, r w is the wellbore radius, k x The permeability of the mesh in the x-direction, k yThe permeability of the grid in the y direction, Δz is the grid thickness, r o is the equivalent radius.

[0149] For upscaling conductivity, if T * If the value is an abnormal value (such as infinite value, Nan, abnormal 0 value or negative value, etc.), it needs to be replaced. Taking the x direction as an example, the specific replacement method is: if the value at the interface of the two coarse grids is If it is an outlier, the coarse-scale permeability of the grid is first calculated based on the geometric mean method for the part with coarse grid i. The coarse-scale permeability of the grid is calculated for the part with coarse grid i+1. Then, the following two formulas are taken in turn:

[0150]

[0151] Among them, Δx, Δy, Δz represent the grid size, is the harmonic mean of the permeability in the x direction of two adjacent grids, that is, the replacement

[0152] For upscaled relative permeability, if the calculated upscaled relative permeability curve has abnormal values ​​(such as negative numbers, infinite values, Nan, relative permeability less than 0 or greater than 1, etc.), it will be replaced by fine-scale relative permeability.

[0153] S3: Substituting the upscaling parameters into the coarse-scale control equations to perform numerical simulation.

[0154] A method for scaling up a carbon dioxide saline layer storage model of the present invention is described below with reference to a specific embodiment.

[0155] The numerical simulation of this embodiment is performed using the CO2STORE module in the Schlumberger Eclipse-E300 component numerical simulation software. This module is based on the CO2 water state equation and can accept the CO2 saline layer storage model with a temperature between 12-250°C and a pressure not exceeding 60MPa. The full physical model used in this embodiment takes into account the effects of gravity, capillary hysteresis, rock / fluid compressibility, solubility, etc., which is closer to the actual situation. The temperature is set to a constant 55°C, and the rock compressibility coefficient is 4.934*10 -4 Mpa -1. The fluid components include water, CO2 and NaCl. Water and CO2 can exist in the liquid phase or gas phase, and NaCl can exist in the liquid phase or solid phase. The CO2STORE module automatically calculates the fluid properties of each phase, such as viscosity, density, and compressibility, based on the grid information. A two-dimensional model defined on the x and z coordinates is adopted, and its permeability is isotropic. The fine-scale model contains 200×100 grids, the grid size is Δx=Δy=Δz=5m, the top interface depth is 1000 meters, and the corresponding pressure is 10Mpa. The model is initially saturated with brine (the composition is 99% water + 1% NaCl). The injection well and the constant pressure boundary are used to drive the model together. The injection well injects CO2 at different rates, and the constant pressure boundary is set to a constant pressure of 10Mpa. A higher pore volume injection (PVI) is used, and the fluid can flow out from the constant pressure boundary. The basic displacement mode considered is lateral flow (from left to right). The focus of this embodiment is on the accuracy of the upscaling method. The designed model can be regarded as a partial area of ​​the actual carbon sequestration model. A higher PVI is set to comprehensively test the accuracy of the coarse-scale model under high CO2 saturation conditions. Detecting the fluid flow passing through the constant pressure boundary is one of the important means to evaluate the accuracy of the upscaling method.

[0156] Table 1 summarizes the model parameters used in this example. In addition, for the permeability field of the model, the left boundary of the model is the CO2 injection well with an injection rate of 0.02Mt / year; the right boundary is a constant pressure boundary with a constant pressure of 10MPa. The number of grids in the fine-scale model is 200×100. After the scale is upgraded, the number of grids in the coarse-scale model is reduced to 20×10, and the scale multiple is 100 times.

[0157] Table 1 Key parameters of fine-scale model

[0158]

[0159] Figure 2 A schematic diagram of the permeability field (ln k) of the fine-scale oblique channel model is shown. Figure 3 The comparison of fine-scale and coarse-scale numerical simulation results is shown. Figure 3 The left figure in the middle shows the gas phase flow through the constant pressure boundary. Figure 3 The right figure in the middle shows the water phase flow through the constant pressure boundary, including the relationship between the gas phase and water phase flow through the constant pressure boundary and PVI under standard conditions (set to 15.56°C, 1 standard atmosphere). Based on the fine-scale numerical simulation results, the scale upscaling method described in the present invention is very accurate compared with the fine-scale numerical simulation method.

[0160] Figure 4 The gas saturation field of the fine-scale and coarse-scale models is shown when PVI = 0.25. Figure 4The left figure in the middle shows the average gas saturation field of the fine-scale model. Figure 4 The right figure in the middle is the gas saturation field of the scale-up method of the present invention; Figure 5 The gas saturation field of the fine-scale and coarse-scale models is shown when PVI = 0.7. Figure 5 The left figure in the middle shows the average gas saturation field of the fine-scale model. Figure 5 The right figure in the middle is the gas saturation field of the upscaling method described in the present invention. The gas saturation fields of other coarse-scale models are compared with the average fine-scale gas saturation field. The results show that the gas saturation field obtained by the upscaling method described in the present invention is very accurate.

[0161] The scale upgrade method of the present invention proposes a model after coarse-scale upgrade. The time consumption results corresponding to the scale upgrade model of the present invention are shown in Table 2 compared with the current fine-scale model. The numerical simulation is accelerated by 280.5 times, which is accurate and has significantly improved efficiency.

[0162] Table 2 Comparison of simulation time results of the scale-up model of the present invention

[0163] Model CPU time / s Scaling multiples Speedup Fine-scale model 2300 — — Scaling model 8.2 10×10＝100 280.5

[0164] The present invention provides a method for scaling up a carbon dioxide saline layer storage model, which significantly reduces the computing resources and time required for simulation, which is particularly important when dealing with large-scale carbon storage models, making the simulation process more efficient and helping to accelerate the research and development and application of carbon storage technology. Through the method of the present invention, the simulation results of the fine-scale model can be more easily applied to actual projects, providing strong support for the design and implementation of carbon storage technology. At the same time, the present invention also provides a strategy for handling outliers to ensure the stability and reliability of the simulation results.

[0165] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for scaling up a carbon dioxide saline aquifer storage model, characterized in that: include: S1: Perform coarse-scale characterization on the fine-scale model control equation to obtain the coarse-scale control equation; S2: perform upscaling calculation on the scale parameter to obtain the upscaling parameter; S3: Substituting the upscaling parameters into the coarse-scale control equations to perform numerical simulation.

2. The method for scaling up a carbon dioxide saline aquifer storage model according to claim 1, characterized in that: Step S1 further comprises: S111: Establish fine-scale model control equations; S112: Perform a coarse-scale characterization on the control equation of the fine-scale model to obtain a coarse-scale control equation.

3. The method for scaling up a carbon dioxide saline aquifer storage model according to claim 2, characterized in that: The fine-scale model control equation in step S111 specifically includes: A fine-scale well model, wherein the fine-scale well model expression is: in, is the flow rate of the well, WI is the well index, p i is the grid pressure of grid i in the fine-scale well model, is the bottom hole pressure of grid i in the fine-scale well model; The fine-scale two-phase flow control equation is expressed as follows: Among them, α is the component index value, M α is the mass accumulation of component α in all phases, F α is the mass flux, q α is the flow rate of component α, and t is the time.

4. The method for scaling up a carbon dioxide saline aquifer storage model according to claim 1, characterized in that: The coarse-scale control equations in step S1 include coarse-scale single-phase flow control equations and coarse-scale two-phase flow control equations.

5. The method for scaling up a carbon dioxide saline aquifer storage model according to claim 4, characterized in that: In step S1, the step of obtaining the coarse-scale single-phase flow control equation specifically includes: S121: Define Darcy's law for single-phase flow; S122: establishing a fine-scale single-phase flow control equation according to the single-phase flow Darcy's law and the mass conservation equation; S123: Replace the fine-scale parameters in the fine-scale single-phase flow control equation with coarse-scale parameters to obtain the coarse-scale single-phase flow control equation.

6. The method for scaling up a carbon dioxide saline aquifer storage model according to claim 5, characterized in that: The expression of the single-phase flow Darcy's law in step S121 is: Among them, u is Darcy velocity, K is permeability tensor, p is pressure, μ is viscosity, ρ is density, and g is gravitational acceleration vector; The expression of the mass conservation equation in step S122 is: Where t is time, φ is porosity, is the source-sink term; The expression of the fine-scale single-phase flow control equation in step S122 is: in, is the volume flow rate; The expression of the coarse-scale single-phase flow control equation in step S123 is: Among them, K * is the permeability tensor under the coarse-scale model, μ c is the viscosity under the coarse-scale model, p c is the pressure in the coarse-scale model, ρ c is the density under the coarse-scale model.

7. The method for scaling up a carbon dioxide saline aquifer storage model according to claim 1, characterized in that: The upscaling parameters in step S2 include: One-way flow scale-up parameters, wherein the one-way flow scale-up parameters include scale-up well index and scale-up conductivity; Two-phase flow scale-up parameters, wherein the two-phase flow scale-up parameters include a scaled capillary force curve and a scaled relative permeability curve.

8. The method for scaling up a carbon dioxide saline aquifer storage model according to claim 7, characterized in that: The step of obtaining the upscaled well index further comprises: S211: Solve the fine-scale single-phase flow control equations at the global scale to obtain fine-scale grid pressure and fine-scale grid flow solutions; S212: Obtaining an upscaled well index by calculating the fine-scale grid pressure and the fine-scale grid flow solution; The step of obtaining the upscaled conductivity further comprises: S221: Obtaining upscaled conductivity by calculating the fine-scale grid pressure and the fine-scale grid flow solution; The step of obtaining the upscaled capillary force curve further comprises: S231: performing coarse grid division on the fine-scale model, and extracting the capillary force curve data of all fine grids inside each coarse grid; S232: Preset a plurality of capillary force values ​​in the selected target coarse grid, and calculate the coarse grid gas saturation of the target coarse grid according to the preset capillary force values ​​and the fine grid gas saturation of each fine grid in the target coarse grid; S233: calculating and obtaining an upscaled capillary force curve of a target coarse grid according to different coarse grid gas saturations corresponding to different preset capillary force values; The step of obtaining the upscaled relative permeability further comprises: S241: Perform two-phase flow numerical simulation on a global scale to obtain numerical simulation results; S242: Calculate the upscaled relative permeability through the numerical simulation results.

9. The method for scaling up a carbon dioxide saline aquifer storage model according to claim 8, characterized in that: The expression of the upscaled well index in step S212 is: Among them, i is the coarse-scale well grid index value, l is the fine-scale well grid index value, is the upscaled well index of the coarse-scale well grid i, is the well flow rate in the fine-scale well grid l, <p f > i is the volume average of all fine grid pressures in the coarse-scale well grid i, represents the volume average of all fine-scale well pressures in the coarse-scale well grid i; The expression of the upscaled conductivity in step S221 is: in, represents the coarse-scale interface between coarse grids i and i+1, T * To calculate the upscaling conductivity, is the sum of the fine grid flow at the coarse-scale interface, <p f > i is the volume average of the fine grid pressure in the coarse grid i, <p f > i+1 is the volume average of the fine grid pressure in the coarse grid i+1, ρ is the density, g is the gravitational acceleration, ΔD c is the depth difference between coarse grids i and i+1; The expression of the upscaled relative permeability in step S242 is: in, is the upscale gas relative permeability, is the upscaled water relative permeability, is the coarse-scale viscosity of the gas phase, is the coarse-scale viscosity of the water phase, is the sum of the gas phase flow rates of the fine grid at the coarse-scale interface, is the sum of the water phase flow rates of the fine grids at the coarse-scale interface, is the upscaled capillary force of the coarse grid i, is the upscaled capillary force of the coarse grid i+1, is the coarse-scale gas density, is the coarse-scale water phase density.

10. The method for scaling up a carbon dioxide saline aquifer storage model according to claim 1, characterized in that: In step S2, when any parameter in the scale-up parameters has an abnormal value, the abnormal value is replaced by a corresponding replacement value.

Images