Evaluation method for improving screening and storage safety of CO2 geological storage site

Abstract

The invention provides an evaluation method for improving CO2 geological sequestration site screening and sequestration safety, and the method comprises the steps: obtaining a region plane structure map, a formation pore pressure gradient and a formation temperature gradient of a target layer through the analysis of geological data, and obtaining the pore pressure plane graphs and the formation temperature plane graphs of different target layers through calculation; and calculating a CO2 density plane graph and a CO2 solubility plane graph of different layers in combination with a formation fluid mineralization degree graph. On the basis, a CO2 geological sequestration capacity plane graph and a CO2 geological sequestration dissolution capacity plane graph can be calculated by combining a reservoir physical property plane graph and a CO2 sequestration coefficient. And then, according to the CO2 density map and the reservoir physical property map, a CO2 reinjection formation pressure change map is rapidly calculated. And an element superposition method is adopted to be combined with all the calculated elements, so that the region-level CO2 geological sequestration site comprehensive dessert plane graph can be obtained. According to the analysis method disclosed by the invention, rapid, efficient and quantitative CO2 site screening is ensured, and the limitation and subjectivity of the prior art are changed.

Description

Technical Field

[0001] The present invention relates to the technical field of CO2 geological storage, and in particular to a method for improving the screening of CO2 geological storage sites and the evaluation of storage safety. Background Art

[0002] At present, the screening of regional CO2 geological storage sites at home and abroad is basically based on qualitative assessment of relevant geological parameters. These geological parameters include commonly used structural depth, reservoir quality, caprock distribution, temperature and pressure system, fluid salinity, etc. By setting different thresholds for each parameter, different zones are divided, and then the storage site is obtained by element superposition method. Its artificiality, subjectivity and uncertainty are relatively large. In order to improve the safety of CO2 geological storage, it is usually necessary to reduce the capacity of free CO2, increase the capacity of bound and dissolved CO2, and ensure that CO2 is stored underground in the form of a supercritical state. The existing technical solutions only use basic geological parameters and use simple element superposition method to describe the screening of CO2 geological storage sites. There is a lack of quantitative description of the properties of CO2 in the process of geological storage from basin level to regional level. Therefore, it is impossible to accurately describe a reasonable and safe CO2 geological storage site.

[0003] During the geological storage process of CO2, its phase, density, and solubility in salt water will change with changes in the pressure, temperature, and salinity of the formation water. This change is usually a nonlinear change. For example, the solubility of CO2 in salt water will increase with increasing pressure and decrease with increasing temperature and salinity. Therefore, it is impossible to simply judge the change in CO2 solubility through a single factor. In addition, the existing technology assumes a fixed CO2 density and solubility when evaluating the regional CO2 geological storage capacity, and lacks consideration of the change in CO2 density due to regional temperature and pressure changes. Under the existing technical solutions, if you want to accurately calculate the changes in CO2 density and solubility during the CO2 geological storage process, you need to use numerical simulation technology, which usually only simulates target-level storage sites. In addition, numerical simulation technology requires a large amount of input data and calculation, and its efficiency is relatively low. It cannot meet the needs of regional-level CO2 geological storage site optimization and rapid evaluation of storage safety. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for improving the screening and safety evaluation of CO2 geological storage sites. By combining digital technology to quickly calculate the plan views of various elements in the CO2 geological storage process at different geological layers at the regional level, the screening and safety of CO2 geological storage sites can be quantitatively evaluated through analytical calculations, ensuring that CO2 site screening is fast, efficient, and quantitative, thereby changing the limitations and subjectivity of existing technologies.

[0005] To achieve the above objectives, the present invention provides a method for improving the screening and storage safety evaluation of CO2 geological storage sites, the method comprising: S11. Obtain geological data of the target site and analyze it to obtain a regional planar structural map, formation pore pressure gradient, and formation temperature gradient of the target layer, thereby obtaining a pore pressure plan map and a formation temperature plan map of different layers; S12. Analyze the acquired geological data to obtain a formation fluid salinity map of the target layer, and combine it with the pore pressure plane map and the formation temperature plane map to obtain a CO2 solubility plane map and a CO2 density plane map for different layers, respectively; S13. Analyze the acquired geological data to obtain a reservoir porosity plane map, a reservoir permeability plane map, and a reservoir thickness plane map of the target layer, combine these with the CO2 density plane map and the CO2 storage coefficient, and obtain a CO2 geological storage capacity plane map for different layers. Combine the CO2 geological storage capacity plane map with the CO2 solubility plane map to obtain a CO2 geological storage dissolution capacity plane map for different layers. S14. Obtain a rock compressibility plane map of the target layer from the reservoir porosity plane map, combine it with the CO2 density plane map, the reservoir porosity plane map, the reservoir permeability plane map, and the reservoir thickness plane map to obtain a CO2 reinjection formation pressure change map, and obtain a minimum required caprock strength plane map for different layers through back calculation; S15. By using the element superposition method, the minimum required cap rock strength plan, the CO2 geological storage capacity plan, and the CO2 geological storage dissolution capacity plan are combined to obtain a regional-level CO2 geological storage site comprehensive sweet spot plan, which is then analyzed to obtain the CO2 geological storage site evaluation and development strategy.

[0006] Furthermore, the geological data is analyzed, including: S21. Use geographic information system technology to integrate and analyze the collected geological data and construct a three-dimensional geological model of the study area; S22. Based on the three-dimensional geological model, select the relevant data required for the target layer of CO2 geological storage, use mapping technology to draw the map data required for the target layer, and calculate the required influencing parameters through corresponding calculation methods.

[0007] Furthermore, in step S11, the pore pressure plane map and formation temperature plane map of different target layers are calculated, which specifically includes: S31. Perform stratigraphic division and comparison based on the drilling core data and logging curves in the geological data, identify the lithologic and electrical properties of the target layer and its upper and lower adjacent layers, and establish stratigraphic comparison marker layers; S32. Based on the 3D geological model, extract the isopach and structural contour lines of the target layer, and draw a regional planar structural map by combining the stratigraphic comparison marker layer; S33, using a formation pressure prediction method, establishing a function model based on pore pressure data in geological data, and calculating the formation pore pressure gradient; S34. Using geothermal principles, combined with regional heat flow values ​​and formation thermal conductivity from geological data, a numerical simulation model of the formation temperature field is established, and temperature gradients at different formation locations are obtained through simulation calculations. S35. Based on the regional planar structural map, the pore pressure gradient and formation temperature gradient data are extended from the well point or measurement point location to the plane range of the entire target layer through interpolation, and the pore pressure plane map and formation temperature plane map of different layers are drawn.

[0008] Furthermore, in step S12, the calculation model of the CO2 solubility plane diagram is:

[0009]

[0010] in, ,

[0011]

[0012]

[0013]

[0014]

[0015] is the solubility of CO2 in pure water, 、 、 、 is the fitting coefficient, is the critical pressure of CO2, is the formation pressure, is the solubility of CO2 in pure water, , For the coefficients, is the formation temperature.

[0016] Furthermore, in step S12, the calculation model of the CO2 density plane map is:

[0017]

[0018]

[0019] in, is the improved CO2 density after considering formation water, , is the formation water density, , In order to consider the CO2 content dissolved in the water after the formation water mineralization, is the apparent molar capacity of CO2, is the molar mass of CO2.

[0020] Furthermore, in step S13, a CO2 geological storage capacity plan is calculated, specifically including: S41, respectively calculating the thickness, porosity, and permeability of the target layer, and interpolating the calculated thickness data, porosity data, and permeability data to the entire study area by an interpolation method to generate a reservoir porosity plane map, a reservoir permeability plane map, and a reservoir thickness plane map; S42. Calculate the reservoir pore volume of different layers based on the reservoir thickness and porosity to obtain the pore volume distribution of the target site; S43. Determine the effective pore volume based on the reservoir permeability and convert the effective pore volume into the CO2 geological storage capacity using the CO2 density and the density values ​​of each point in the pore volume distribution of the target site; S44. Based on the CO2 storage coefficient, the CO2 geological storage capacity is interpolated to the entire target site by an interpolation method to obtain a CO2 geological storage capacity plan map.

[0021] Furthermore, in step S13, a plan view of the CO2 geological storage dissolution capacity is calculated, specifically including: S51. Based on the CO2 solubility diagram and the pore volume of formation water, calculate the amount of CO2 dissolved in formation water; S52, integrating the CO2 geological storage capacity and the corresponding CO2 dissolution amount at each location in the CO2 geological storage capacity plan map, and calculating the dissolution capacity at each location in the CO2 geological storage dissolution capacity plan map; S53. Interpolate the calculated CO2 geological storage dissolution capacity data to the entire target site through an interpolation method to obtain a CO2 geological storage dissolution capacity plan map.

[0022] Furthermore, in step S14, a rock compressibility plane map is obtained from the reservoir porosity plane map, specifically including: S61. Calculate the rock skeleton compression coefficient based on the rock mineral composition data; S62. Based on the reservoir porosity plane diagram, calculate the volume change rate of the pore fluid under pressure change to obtain the fluid compressibility coefficient; S63. Calculate the rock compressibility by combining the rock skeleton compressibility and the fluid compressibility; S64. Interpolate the calculated rock compression coefficient data to generate a rock compression coefficient plane diagram.

[0023] Furthermore, in step S14, a CO2 reinjection formation pressure change diagram is generated, specifically including: S71. Calculate the initial formation pressure based on the reservoir porosity, permeability, thickness, and rock compressibility, and calculate the CO2 injection rate based on the given CO2 reinjection rate and CO2 density; S72. Based on the initial formation pressure and the CO2 injection rate, the change of the target layer pressure over time is calculated through numerical simulation, and a CO2 reinjection formation pressure change graph is generated.

[0024] Furthermore, in step S15, a regional-level CO2 geological storage site comprehensive sweet spot map is calculated, specifically including: S81. spatially superimpose the minimum required cap rock strength plan map, the CO2 geological storage capacity plan map, and the CO2 geological storage dissolution capacity plan map, so that each grid point or location simultaneously has a cap rock strength score, a storage capacity score, and a dissolution capacity score; S82. Preset the weights of various factors in the CO2 geological storage site evaluation, multiply the scores of each grid point by the corresponding weights, and add them together to obtain a comprehensive sweetness value; S83. Based on the size of the comprehensive sweetness value, each grid point or location is divided into different sweetness levels to generate a regional-level CO2 geological storage site comprehensive sweet spot plan.

[0025] Compared with the prior art, the present invention has the following beneficial effects: This invention provides a method for improving the screening and safety evaluation of CO2 geological storage sites. Based on the basic data of existing solutions, the invention uses an analytical method to rapidly and quantitatively calculate capacity- and safety-related plans, including CO2 storage capacity and CO2 dissolution capacity. The quantitative plans obtained through analytical calculations are then applied using a factor overlay method to produce an optimized regional-level comprehensive sweet spot plan for CO2 geological storage sites. This method reduces the subjective judgment and uncertainty inherent in the selection of CO2 geological storage sites, while maximizing both CO2 storage capacity and safety, reducing potential project risks and improving project economics and safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without any creative work. Figure 1 A schematic flow chart of a method for improving the screening and storage safety of CO2 geological storage sites provided by an embodiment of the present invention; Figure 2 A schematic diagram of a technical guidance route for a method for improving the screening and storage safety of CO2 geological storage sites provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0027] The present invention will be further described in detail below with reference to the accompanying drawings and examples. It will be understood that the specific embodiments described herein are intended only to illustrate the present invention and are not intended to limit the present invention. It should also be noted that, for ease of description, the accompanying drawings only illustrate portions relevant to the present invention, not all structures.

[0028] Reference Figure 1 This embodiment provides a method for improving the screening and storage safety evaluation of CO2 geological storage sites, the method comprising: S11. Obtain geological data of the target site and analyze it to obtain a regional planar structural map, formation pore pressure gradient, and formation temperature gradient of the target layer, thereby obtaining a pore pressure plan map and a formation temperature plan map of different layers; S12. Analyze the acquired geological data to obtain a formation fluid salinity map of the target layer, and combine it with the pore pressure plane map and the formation temperature plane map to obtain a CO2 solubility plane map and a CO2 density plane map for different layers, respectively; S13. Analyze the acquired geological data to obtain a reservoir porosity plane map, a reservoir permeability plane map, and a reservoir thickness plane map of the target layer, combine these with the CO2 density plane map and the CO2 storage coefficient, and obtain a CO2 geological storage capacity plane map for different layers. Combine the CO2 geological storage capacity plane map with the CO2 solubility plane map to obtain a CO2 geological storage dissolution capacity plane map for different layers. S14. Obtain a rock compressibility plane map of the target layer from the reservoir porosity plane map, combine it with the CO2 density plane map, the reservoir porosity plane map, the reservoir permeability plane map, and the reservoir thickness plane map to obtain a CO2 reinjection formation pressure change map, and obtain a minimum required caprock strength plane map for different layers through back calculation; S15. By using the element superposition method, the minimum required cap rock strength plan, the CO2 geological storage capacity plan, and the CO2 geological storage dissolution capacity plan are combined to obtain a regional-level CO2 geological storage site comprehensive sweet spot plan, which is then analyzed to obtain the CO2 geological storage site evaluation and development strategy.

[0029] In this example, a comprehensive sweet spot plan for CO2 geological storage sites at different geological layers at the regional level is calculated, and then analytically derived from this CO2 geological storage site evaluation and development strategy. Because the method incorporates all geological parameters from existing solutions, it enables quantitative evaluation of CO2 geological storage site screening and safety. This analytical calculation ensures rapid, efficient, and quantitative site screening, overcoming the limitations and subjectivity of existing technologies.

[0030] As a preferred embodiment, the geological data is analyzed, specifically including: S21. Use geographic information system technology to integrate and analyze the collected geological data and construct a three-dimensional geological model of the study area; S22. Based on the three-dimensional geological model, select the relevant data required for the target layer of CO2 geological storage, use mapping technology to draw the map data required for the target layer, and calculate the required influencing parameters through corresponding calculation methods.

[0031] In this embodiment, the collected geological data are used to model the geological body through geostatistical methods and numerical simulation technology to determine the distribution characteristics of the reservoir and cap rock, providing a geological basic framework for CO2 site screening.

[0032] As a preferred embodiment, in step S11, calculating and obtaining the pore pressure plane map and formation temperature plane map of different target layers specifically includes: S31. Divide and compare strata based on the drilling core data and logging curves in the geological data, identify the lithologic and electrical properties of the target layer and its upper and lower adjacent strata, and establish a stratigraphic comparison marker layer.

[0033] S32. Based on the three-dimensional geological model, extract the isopach and structural contour lines of the target layer, combine them with the stratigraphic comparison marker layer, and draw the regional planar structural map.

[0034] S33. Using the formation pressure prediction method, a function model is established based on the pore pressure data in the geological data to calculate the formation pore pressure gradient.

[0035] S34. Using geothermal principles, combined with the regional heat flow value and thermal conductivity of the formation in the geological data, a numerical simulation model of the formation temperature field is established, and the temperature gradient at different formation locations is obtained through simulation calculation.

[0036] S35. Based on the regional planar structural map, the pore pressure gradient and formation temperature gradient data are extended from the well point or measurement point location to the plane range of the entire target layer through interpolation, and the pore pressure plane map and formation temperature plane map of different layers are drawn.

[0037] In this example, high pore pressure areas may induce fault slip or rock fracture, impacting CO2 storage safety. A pore pressure plot provides a visual representation of formation pressure distribution. In lower-pressure areas, CO2 injection requires less pressure, leading to smoother injection. Higher-pressure areas may require more energy to maintain injection. A formation temperature plot helps understand the thermal state of the formation. CO2 injection in high-temperature areas may cause thermal disturbances, affecting the properties of surrounding rocks and fluids, and thus impacting storage stability. Combined with the formation temperature plot, temperature influences the phase and density of CO2. In low-temperature areas, CO2 tends to exist in a liquid or supercritical state, resulting in higher density and greater storage capacity. Understanding the pore pressure and temperature distribution provides a data foundation for comprehensively identifying favorable areas for CO2 storage. Furthermore, by adjusting injection parameters and implementing temperature and pressure control measures, CO2 can be stabilized in the formation, reducing its potential for migration and escape, and enhancing the long-term stability of CO2 storage.

[0038] As a preferred embodiment, in step S12, the calculation model of the CO2 solubility plane diagram is:

[0039]

[0040] in, ,

[0041]

[0042]

[0043]

[0044]

[0045] is the solubility of CO2 in pure water, 、 、 、 is the fitting coefficient, is the critical pressure of CO2, is the formation pressure, is the solubility of CO2 in pure water, , For the coefficients, is the formation temperature.

[0046] In this embodiment, since CO2 solubility varies with formation temperature, pressure and fluid salinity, it is necessary to establish a calculation model of regional CO2 solubility and temperature, pressure and solubility, so as to study the variation pattern of CO2 dissolution rate in regional saline water layers.

[0047] As a preferred embodiment, in step S12, the calculation model of the CO2 density plane map is:

[0048]

[0049]

[0050] in, is the improved CO2 density after considering formation water, , is the formation water density, , In order to consider the CO2 content dissolved in the water after the formation water mineralization, is the apparent molar capacity of CO2, is the molar mass of CO2.

[0051] As a preferred embodiment, in step S13, calculating and obtaining a plan view of the CO2 geological storage capacity specifically includes: S41, respectively calculating the thickness, porosity, and permeability of the target layer, and interpolating the calculated thickness data, porosity data, and permeability data to the entire study area by an interpolation method to generate a reservoir porosity plane map, a reservoir permeability plane map, and a reservoir thickness plane map; S42. Calculate the reservoir pore volume of different layers based on the reservoir thickness and porosity to obtain the pore volume distribution of the target site; S43. Determine the effective pore volume based on the reservoir permeability and convert the effective pore volume into the CO2 geological storage capacity using the CO2 density and the density values ​​of each point in the pore volume distribution of the target site; S44. Based on the CO2 storage coefficient, the CO2 geological storage capacity is interpolated to the entire target site by an interpolation method to obtain a CO2 geological storage capacity plan map.

[0052] In this embodiment, the CO2 geological storage capacity plan of different layers is calculated, which can intuitively present the CO2 storage capacity of each layer, help to accurately locate areas with outstanding storage capacity, improve site screening efficiency, and reduce ineffective exploration.

[0053] As a preferred embodiment, in step S13, calculating and obtaining a plan view of the CO2 geological storage dissolution capacity specifically includes: S51. Based on the CO2 solubility diagram and the pore volume of formation water, calculate the amount of CO2 dissolved in formation water; S52, integrating the CO2 geological storage capacity and the corresponding CO2 dissolution amount at each location in the CO2 geological storage capacity plan map, and calculating the dissolution capacity at each location in the CO2 geological storage dissolution capacity plan map; S53. Interpolate the calculated CO2 geological storage dissolution capacity data to the entire target site through an interpolation method to obtain a CO2 geological storage dissolution capacity plan map.

[0054] In this embodiment, CO2 dissolution is a long-term process. The dissolution capacity plane diagram can intuitively present the distribution of CO2 dissolution capacity in different layers. After clarifying the difference in dissolution capacity of each layer, the long-term CO2 dissolution amount in different layers can be predicted, the storage effect can be evaluated, and the storage stability can be understood in advance.

[0055] As a preferred embodiment, in step S14, obtaining a rock compressibility plane map from a reservoir porosity plane map specifically includes: S61. Calculate the rock skeleton compression coefficient based on the rock mineral composition data; S62. Based on the reservoir porosity plane diagram, calculate the volume change rate of the pore fluid under pressure change to obtain the fluid compressibility coefficient; S63. Calculate the rock compressibility by combining the rock skeleton compressibility and the fluid compressibility; S64. Interpolate the calculated rock compression coefficient data to generate a rock compression coefficient plane diagram.

[0056] In this example, the porosity plot primarily reflects the reservoir's pore structure, while the rock compressibility plot further illustrates the volumetric changes of the reservoir rock under varying pressure, reflecting the degree of rock volume change under varying pressure. In CO2 geological storage, considering the rock compressibility can more accurately estimate the reservoir's elastic storage capacity, preventing formation fractures or geological disasters caused by excessive injection pressure.

[0057] As a preferred embodiment, in step S14, generating a CO2 reinjection formation pressure change map specifically includes: S71. Calculate the initial formation pressure based on the reservoir porosity, permeability, thickness, and rock compressibility, and calculate the CO2 injection rate based on the given CO2 reinjection rate and CO2 density; S72. Based on the initial formation pressure and the CO2 injection rate, the change of the target layer pressure over time is calculated through numerical simulation, and a CO2 reinjection formation pressure change graph is generated.

[0058] In this embodiment, based on the CO2 density plane map obtained by the above calculation, combined with the reservoir porosity plane map, reservoir permeability plane map and reservoir thickness plane map, the change map of formation pressure with reinjection time at a given reinjection rate can be quickly calculated. Usually, the pressure change reaches the maximum when the reinjection stops. In order to ensure that the formation pressure does not break the overburden, the minimum required cap rock strength can be inversely calculated to support the pressure change caused by reinjection. Since the cap rock strength varies at different levels and depths, a relatively safe storage site can be obtained through this method.

[0059] As a preferred embodiment, in step S15, the calculation of the regional-level CO2 geological storage site comprehensive sweet spot plan specifically includes: S81. spatially superimpose the minimum required cap rock strength plan map, the CO2 geological storage capacity plan map, and the CO2 geological storage dissolution capacity plan map, so that each grid point or location simultaneously has a cap rock strength score, a storage capacity score, and a dissolution capacity score; S82. Preset the weights of various factors in the CO2 geological storage site evaluation, multiply the scores of each grid point by the corresponding weights, and add them together to obtain a comprehensive sweetness value; S83. Based on the size of the comprehensive sweetness value, each grid point or location is divided into different sweetness levels to generate a regional-level CO2 geological storage site comprehensive sweet spot plan.

[0060] In this embodiment, a single geological factor cannot fully measure the pros and cons of a CO2 geological storage site. For example, if only areas with large storage capacity are considered, the cap rock strength in the area may be insufficient and CO2 cannot be safely stored; if only areas with high cap rock strength are focused on, the storage capacity or dissolution capacity may be limited, making large-scale and efficient storage impossible. The key element plan views are integrated through the element superposition method, and the natural break point method or the equal spacing method is used to determine the sweetness level division threshold based on the size of the comprehensive sweetness value. Each grid point or location is divided into different sweetness levels, such as "high sweet spot", "medium sweet spot", "low sweet spot", or a continuous color gradient is used to represent the change in sweetness, thereby generating a regional-level CO2 geological storage site comprehensive sweet spot plan view.

[0061] By analyzing the comprehensive dessert plan, high-sweetness areas are identified. These areas usually have better cap rock strength, larger storage capacity and higher dissolution capacity, and are priority candidate areas for CO2 geological storage sites. At the same time, the medium-sweetness and low-sweetness areas are analyzed to find out their advantages and disadvantages, providing a basis for the formulation of subsequent development strategies. A detailed analysis is conducted on the distribution range, continuity, and relationship with other geological structures and engineering facilities of areas with different sweetness levels to evaluate their feasibility and potential in actual projects. For example, whether the high-sweetness area has sufficient area and connectivity to meet the needs of large-scale CO2 storage, and whether it matches the location of the CO2 emission source. In this way, high-quality sites that perform well in many aspects such as safety, storage capacity and efficiency are accurately identified, while unsuitable sites with obvious defects are screened out.

[0062] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for improving the screening and storage safety evaluation of CO2 geological storage sites, characterized in that: The method comprises: S11. Obtain geological data of the target site and analyze it to obtain a regional planar structural map, formation pore pressure gradient, and formation temperature gradient of the target layer, thereby obtaining a pore pressure plan map and a formation temperature plan map of different layers; S12. Analyze the acquired geological data to obtain a formation fluid salinity map of the target layer, and combine it with the pore pressure plane map and the formation temperature plane map to obtain a CO2 solubility plane map and a CO2 density plane map for different layers, respectively; S13. Analyze the acquired geological data to obtain a reservoir porosity plane map, a reservoir permeability plane map, and a reservoir thickness plane map of the target layer, combine these with the CO2 density plane map and the CO2 storage coefficient, and obtain a CO2 geological storage capacity plane map for different layers. Combine the CO2 geological storage capacity plane map with the CO2 solubility plane map to obtain a CO2 geological storage dissolution capacity plane map for different layers. S14. Obtain a rock compressibility plane map of the target layer from the reservoir porosity plane map, combine it with the CO2 density plane map, the reservoir porosity plane map, the reservoir permeability plane map, and the reservoir thickness plane map to obtain a CO2 reinjection formation pressure change map, and obtain a minimum required caprock strength plane map for different layers through back calculation; S15. By using the element superposition method, the minimum required cap rock strength plan, the CO2 geological storage capacity plan, and the CO2 geological storage dissolution capacity plan are combined to obtain a regional-level CO2 geological storage site comprehensive sweet spot plan, which is then analyzed to obtain the CO2 geological storage site evaluation and development strategy.

2. The method for improving the screening and storage safety evaluation of CO2 geological storage sites according to claim 1, characterized in that: Analyze geological data, including: S21. Use geographic information system technology to integrate and analyze the collected geological data and construct a three-dimensional geological model of the study area; S22. Based on the three-dimensional geological model, select the relevant data required for the target layer of CO2 geological storage, use mapping technology to draw the map data required for the target layer, and calculate the required influencing parameters through corresponding calculation methods.

3. The method for improving the screening and storage safety evaluation of CO2 geological storage sites according to claim 2, characterized in that: In step S11, the pore pressure plane map and formation temperature plane map of different target layers are calculated, which specifically includes: S31. Perform stratigraphic division and comparison based on the drilling core data and logging curves in the geological data, identify the lithologic and electrical properties of the target layer and its upper and lower adjacent layers, and establish stratigraphic comparison marker layers; S32. Based on the 3D geological model, extract the isopach and structural contour lines of the target layer, and draw a regional planar structural map by combining the stratigraphic comparison marker layer; S33, using a formation pressure prediction method, establishing a function model based on pore pressure data in geological data, and calculating the formation pore pressure gradient; S34. Using geothermal principles, combined with regional heat flow values ​​and formation thermal conductivity from geological data, a numerical simulation model of the formation temperature field is established, and temperature gradients at different formation locations are obtained through simulation calculations. S35. Based on the regional planar structural map, the pore pressure gradient and formation temperature gradient data are extended from the well point or measurement point location to the plane range of the entire target layer through interpolation, and the pore pressure plane map and formation temperature plane map of different layers are drawn.

4. The method for improving the screening and storage safety evaluation of CO2 geological storage sites according to claim 1, characterized in that: In step S12, the calculation model of the CO2 solubility plane diagram is: in, ， is the solubility of CO2 in pure water, 、 、 、 is the fitting coefficient, is the critical pressure of CO2, is the formation pressure, is the solubility of CO2 in pure water, , For the coefficients, is the formation temperature.

5. The method for improving the screening and storage safety evaluation of CO2 geological storage sites according to claim 4, characterized in that: In step S12, the calculation model of the CO2 density plane map is: in, is the improved CO2 density after considering formation water, , is the formation water density, , In order to consider the CO2 content dissolved in the water after the formation water mineralization, is the apparent molar capacity of CO2, is the molar mass of CO2.

6. The method for improving the screening and storage safety evaluation of CO2 geological storage sites according to claim 1, characterized in that: In step S13, a plan view of the CO2 geological storage capacity is calculated, specifically including: S41, respectively calculating the thickness, porosity, and permeability of the target layer, and interpolating the calculated thickness data, porosity data, and permeability data to the entire study area by an interpolation method to generate a reservoir porosity plane map, a reservoir permeability plane map, and a reservoir thickness plane map; S42. Calculate the reservoir pore volume of different layers based on the reservoir thickness and porosity to obtain the pore volume distribution of the target site; S43. Determine the effective pore volume based on the reservoir permeability and convert the effective pore volume into the CO2 geological storage capacity using the CO2 density and the density values ​​of each point in the pore volume distribution of the target site; S44. Based on the CO2 storage coefficient, the CO2 geological storage capacity is interpolated to the entire target site by an interpolation method to obtain a CO2 geological storage capacity plan map.

7. The method for improving the screening and storage safety evaluation of CO2 geological storage sites according to claim 1, characterized in that: In step S13, a plan view of the CO2 geological storage dissolution capacity is calculated, specifically including: S51. Based on the CO2 solubility diagram and the pore volume of formation water, calculate the amount of CO2 dissolved in formation water; S52, integrating the CO2 geological storage capacity and the corresponding CO2 dissolution amount at each location in the CO2 geological storage capacity plan map, and calculating the dissolution capacity at each location in the CO2 geological storage dissolution capacity plan map; S53. Interpolate the calculated CO2 geological storage dissolution capacity data to the entire target site through an interpolation method to obtain a CO2 geological storage dissolution capacity plan map.

8. The method for improving the screening and storage safety evaluation of CO2 geological storage sites according to claim 1, characterized in that: In step S14, the rock compressibility plane map is obtained from the reservoir porosity plane map, which specifically includes: S61. Calculate the rock skeleton compression coefficient based on the rock mineral composition data; S62. Based on the reservoir porosity plane diagram, calculate the volume change rate of the pore fluid under pressure change to obtain the fluid compressibility coefficient; S63. Calculate the rock compressibility by combining the rock skeleton compressibility and the fluid compressibility; S64. Interpolate the calculated rock compression coefficient data to generate a rock compression coefficient plane diagram.

9. The method for improving the screening and storage safety evaluation of CO2 geological storage sites according to claim 1, characterized in that: In step S14, a CO2 reinjection formation pressure change diagram is generated, specifically including: S71. Calculate the initial formation pressure based on the reservoir porosity, permeability, thickness, and rock compressibility, and calculate the CO2 injection rate based on the given CO2 reinjection rate and CO2 density; S72. Based on the initial formation pressure and the CO2 injection rate, the change of the target layer pressure over time is calculated through numerical simulation, and a CO2 reinjection formation pressure change graph is generated.

10. The method for improving the screening and storage safety evaluation of CO2 geological storage sites according to claim 1, characterized in that: In step S15, a comprehensive sweet spot plan of a regional CO2 geological storage site is calculated, specifically including: S81. spatially superimpose the minimum required cap rock strength plan map, the CO2 geological storage capacity plan map, and the CO2 geological storage dissolution capacity plan map, so that each grid point or location simultaneously has a cap rock strength score, a storage capacity score, and a dissolution capacity score; S82. Preset the weights of various factors in the CO2 geological storage site evaluation, multiply the scores of each grid point by the corresponding weights, and add them together to obtain a comprehensive sweetness value; S83. Based on the size of the comprehensive sweetness value, each grid point or location is divided into different sweetness levels to generate a regional-level CO2 geological storage site comprehensive sweet spot plan.

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