Method for evaluating influence of carbon dioxide leakage in carbon sequestration project on underground water environment

Abstract

The invention discloses a method for evaluating the influence of carbon dioxide leakage of a carbon sequestration project on an underground water environment. The method comprises the steps of determining a monitoring area; determining a monitoring point; background value data and a monitoring datum line are determined; carrying out a CO2-H2O reaction experiment to obtain the influence mechanism of CO2 leakage on different media, and screening out sensitive monitoring indexes; actual monitoring indexes are screened out, and monitoring equipment matched with the actual monitoring indexes in type is found for the actual monitoring indexes; determining the model and specification of the used monitoring equipment for the monitoring point; and after CO2 is injected, monitoring equipment is arranged at each monitoring point. And comparing the monitoring data obtained by the monitoring equipment with the monitoring datum line to determine whether CO2 leakage occurs or not and the influence of CO2 leakage on the groundwater environment. According to the invention, for a carbon sequestration engineering implementation area, whether CO2 leaks or not and the influence of leaked CO2 on the groundwater environment can be evaluated truly and objectively.

Description

Technical Field

[0001] The present invention relates to a method for evaluating the impact of groundwater environment, in particular to a method for evaluating the impact of carbon dioxide leakage on groundwater environment used in carbon sequestration projects. Background Art

[0002] With the proposal of the "dual carbon" goal, carbon sequestration projects have been carried out in large numbers. Carbon sequestration refers to the process of capturing carbon and storing it safely instead of directly emitting CO2 into the atmosphere. 2 technology, which can reduce the concentration of carbon dioxide in the atmosphere and thus effectively address the problem of global climate change. 2 Large-scale injection may be accompanied by geological activities such as the development of deep coal or oil and gas resources, poor sealing of abandoned wellbores, or natural earthquakes (in extreme cases). These geological activities may cause the cap rock to rupture, thus causing the injected underground CO to be stored. 2 There is a risk of leakage. CO 2 Once the leakage enters the recharge layer of underground freshwater, it will cause groundwater pollution. When the polluted groundwater reaches the surface, it will harm the soil environment and ecosystem, and endanger human health and safety. 2 Whether a leak occurs and the amount of CO leaked 2 Monitoring the impact on the groundwater environment is a key link in carbon sequestration projects. At present, the traditional approach is to install monitoring equipment in the area where the carbon sequestration project is implemented to monitor CO 2 Whether a leak occurs and the amount of CO leaked 2 However, from the actual implementation, it can be found that there are many types of monitoring equipment, and it is difficult to select suitable monitoring equipment according to the characteristics of the carbon storage project implementation area. In addition, the traditional practice is to send the samples collected by the monitoring equipment back to the laboratory for monitoring. The results obtained from such monitoring are often very different from the actual situation due to changes in the monitoring environment, and cannot truly reflect the actual situation in the carbon storage project implementation area. 2 Whether leakage occurs and the technical solutions to the impact on the groundwater environment are issues that need to be urgently addressed. Summary of the invention

[0003] The purpose of the present invention is to provide a method for evaluating the impact of carbon dioxide leakage from a carbon storage project on groundwater environment, which can evaluate the impact of carbon dioxide leakage on groundwater environment in the carbon storage project implementation area. 2 Whether a leak occurs and the amount of CO leaked 2 Provide a true and objective evaluation of the impact on the groundwater environment.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions:

[0005] An evaluation method for the impact of carbon dioxide leakage from a carbon sequestration project on the groundwater environment, comprising the steps of:

[0006] 1) Determine the monitoring area according to the site conditions and geological conditions of the carbon sequestration project implementation area. Among them, the monitoring area is located within the carbon sequestration project implementation area, and the monitoring area includes a core area and an extended area. The core area is within the extended area and the area of the extended area is much larger than that of the core area;

[0007] 2) Conduct a risk point investigation within the monitoring area. Based on geological data, geophysical exploration data, drilling data, logging data, and rock water sample test data, and combined with the actual situation of field exploration, determine potential CO 2 leakage risk points as monitoring points;

[0008] 3) Determine the background value data representing the groundwater quality of the carbon sequestration project implementation area by on-site water quality rapid inspection, on-site simple experimental testing, and laboratory water quality full analysis testing within the monitoring area, so as to determine the monitoring baseline for comparison with the monitoring data obtained after injecting CO 2 ;

[0009] 4) Conduct CO 2 -H 2 O reaction experiments on the formation water, deionized water, and prepared liquid of the composition of simulated formation water at the corresponding horizons that can be obtained within the monitoring area through an experimental device, learn about the influence degree of CO 2 on different media under different monitoring indicators, obtain the influence mechanism of CO 2 leakage on different media, and then screen out sensitive monitoring indicators from all the monitoring indicators affecting the groundwater environment;

[0010] 5) Combine the site conditions and geological conditions of the monitoring area, screen out the actual monitoring indicators suitable for the monitoring area from all the sensitive monitoring indicators, and find monitoring equipment with a suitable type for each actual monitoring indicator;

[0011] 6) According to the site conditions and geological conditions of the monitoring points, clarify the models and specifications of the monitoring equipment used to monitor each of the actual monitoring indicators corresponding to this monitoring point for each monitoring point. Among them, set the danger threshold of CO 2 leakage and the upper limit values corresponding to each actual monitoring indicator. When the danger threshold or the upper limit value is exceeded, it means that it will cause harm to the human body, and thus a harm alarm is issued to persuade people to move away;

[0012] 7) Inject CO 2Afterwards, corresponding monitoring devices are arranged at each of the monitoring points, and each of the monitoring devices communicates with a monitoring center through the Internet of Things. Among them, the monitoring data obtained by the monitoring devices is compared with the monitoring baseline to determine whether there is CO 2 leakage and the impact of CO 2 leakage on the groundwater environment, so as to objectively evaluate the impact of CO 2 leakage on the groundwater environment within the monitoring area in real time.

[0013] The advantages of the present invention are as follows:

[0014] The present invention provides a way to make a true, objective and real-time evaluation of the impact of carbon dioxide leakage on the groundwater environment in carbon sequestration projects. The key lies in that the evaluation results can truly reflect the objective situation and are real-time. Specifically, the present invention considers from the mechanism of the impact of CO 2 leakage on the groundwater environment, and selects sensitive monitoring indicators through CO 2 -H 2 O reaction experiments from the influencing factors such as the water quality, physical and chemical parameters, hydrochemical components, harmful elements, and gas-phase components of groundwater, and further optimizes the actual monitoring indicators considering the applicability of the monitoring area. Based on the actual monitoring indicators, the most suitable monitoring devices are selected to conduct real-time monitoring of the monitoring points, and a monitoring and early warning platform is constructed based on the Internet of Things, providing a favorable guarantee for timely evaluating the impact of CO 2 leakage on the groundwater environment. Description of the Drawings

[0015] Figure 1 is a schematic diagram of the composition of the experimental device used in the method of the present invention. Detailed Embodiments

[0016] The present invention proposes a method for evaluating the impact of carbon dioxide leakage on the groundwater environment in carbon sequestration projects, which specifically includes the following steps:

[0017] 1) According to the site conditions, geological conditions, etc. of the carbon sequestration project implementation area, determine the monitoring area. Among them, the monitoring area is located within the carbon sequestration project implementation area, and the monitoring area includes a core area and an extension area. The core area is within the extension area and the area of the extension area is much larger than that of the core area;

[0018] 2) Conduct a risk point survey within the monitoring area. Based on the collection and analysis of data such as geological data, geophysical exploration data, drilling data, logging data, and rock water sample test data, and combined with the actual situation of field exploration, determine the potential CO 2 leakage risk points as monitoring points;

[0019] 3) Conduct groundwater environment investigation and monitoring within the monitoring area. Determine the background value data representing the groundwater quality in the area where the carbon sequestration project is implemented through methods such as on-site rapid water quality testing, on-site simple experimental testing, and laboratory full water quality analysis testing, so as to determine the monitoring baseline for comparison with the monitoring data obtained after injecting CO 2 ;

[0020] 4) Conduct CO 2 -H 2 O reaction experiments on the formation water (or groundwater) of the corresponding horizons, deionized water, and the prepared liquid with the composition of simulated formation water that can be obtained within the monitoring area through experimental devices. Understand the influence degree of CO 2 on different media under different monitoring indicators, obtain the influence mechanism of CO 2 leakage on different media, and then screen out sensitive monitoring indicators from all monitoring indicators affecting the groundwater environment;

[0021] 5) Based on the statistical analysis of the monitoring technical methods for sensitivity indicators, conduct research on the adaptability of sensitivity indicators and instrumentation. Combine the site conditions, geological conditions, etc. of the monitoring area, screen out the actual monitoring indicators suitable for the monitoring area from all sensitive monitoring indicators, and find the type-matched monitoring equipment for each actual monitoring indicator;

[0022] 6) According to the site conditions, geological conditions, etc. of the monitoring points, clarify the model and specifications of the monitoring equipment used to monitor each actual monitoring indicator corresponding to this monitoring point for each monitoring point. Among them, refer to relevant standards and specifications (mainly the "Technical Guidelines for Geological Sequestration Monitoring of Carbon Dioxide" and the "Technical Specifications for Quantification and Verification of Greenhouse Gas Emission Reduction in Carbon Capture, Utilization and Storage Projects"), and comprehensively consider the carbon sequestration project and site conditions to set the hazard threshold of CO 2 leakage and the upper limit values corresponding to each actual monitoring indicator. When the hazard threshold or upper limit value is exceeded, it indicates that it will cause harm to humans, and thus a hazard alarm will be issued to persuade people to move away;

[0023] 7) After injecting CO 2 in the area where the carbon sequestration project is implemented, deploy the corresponding monitoring equipment at each monitoring point. Each monitoring equipment communicates with the monitoring center through the Internet of Things. Among them, compare the monitoring data obtained by the monitoring equipment with the monitoring baseline to determine whether CO 2 leakage occurs and the impact of CO 2 leakage on the groundwater environment (here, the judgment basis for CO 2 leakage and its impact on the groundwater environment is given by the CO 2 -H 2 O reaction experiment conducted in step 4)), so as to objectively evaluate the impact of CO 2 leakage on the groundwater environment within the monitoring area in real time.

[0024] In the present invention, the site conditions, such as whether it involves the development of deep coal or oil and gas resources, whether there are abandoned wellbores, etc., and the geological conditions, such as whether there are developed faults and fractures, whether it is prone to natural earthquakes, etc. Determining a reasonable range of monitoring areas within the carbon sequestration project implementation area is a well-known technology in the art. The characteristics of CO 2 migration underground and other situations can be reflected from the site conditions, geological conditions, etc., and then used to plan the monitoring area. In addition, in addition to considering the site conditions, geological conditions, etc., the range of the monitoring area can also be reasonably designed in combination with engineering practice experience.

[0025] In actual implementation, the area sizes of the core area and the extension area should be reasonably designed according to the carbon sequestration project implementation area and actual requirements. Usually, the core area and the extension area are designed as circular or square areas. For example, the core area is a square area of 1 km × 1 km, and the extension area is a square area of 10 km × 10 km, without limitation.

[0026] In the present invention, the investigation of risk points in the monitoring area is usually carried out based on indicators such as geological risk, engineering risk, environmental risk, and health risk, and of course, there is no limitation. And potential CO 2 leakage risk points should, based on the determined risk points, be verified and evaluated for each risk point with emphasis on geological risk and environmental risk based on existing geological data, geophysical exploration data, drilling data, logging data, and rock water sample test data, as well as the actual situation of field exploration, so as to select a part of the risk points as monitoring points. The determination process of these risk points and monitoring points is a well-known technology in the art and should be reasonably designed and adjusted according to the actual situation, and will not be elaborated here.

[0027] In practice, the formation for injecting CO 2 can be in deep layers, buffer layers, medium shallow layers, near the surface, etc., without limitation.

[0028] In step 3), the background value data is the groundwater data obtained for the monitoring area before CO 2 injection. The groundwater data is, for example, pH value, conductivity, temperature, dissolved oxygen, etc. The background value data is measured through the wellbore.

[0029] In actual implementation, for different types of groundwater data, one of the methods such as on-site water quality rapid inspection, on-site simple experimental testing, and laboratory water quality full analysis testing is selected for testing. These are all conventional methods in the art and are not limited. On-site simple experimental testing is, for example, the testing of easily variable components such as HCO 3 - , CO 3 2- , CO 2 , etc.

[0030] In the present invention, the background value data serves as a benchmark for comparison. For example, if it is higher than the benchmark to a certain extent, it is determined that CO has occurred. 2 leakage.

[0031] In practice, the wellbore can be an existing injection well, monitoring well, transformed abandoned well, etc., or a dedicated monitoring well drilled on-site (recommended).

[0032] In step 4), such as Figure 1 , the experimental device includes four fully sealed pressure-resistant plexiglass covers arranged side by side. Among them, three glass covers serve as formation comparison covers 10, and the remaining one glass cover serves as a pure gas comparison cover 20. The bottoms of the formation comparison covers 10 are respectively connected to the outlets of a gas-liquid mixing device 50 via injection pipes 60. Control valves 61 are provided on each injection pipe 60. The control valves 61 are used to control the entry of the gas-liquid mixture into the formation comparison covers 10. The inlets of each gas-liquid mixing device 50 are divided into two paths. One path is connected to a plunger pump 42 via a gas supply pipe 40. An intake valve 43 is provided on the gas supply pipe 40 connected to the inlet of each gas-liquid mixing device 50. The other path is connected to a liquid supply device (not shown in the figure) via a liquid supply pipe 30. The liquid supply device is used to provide brine. An injection valve 31 is provided on the liquid supply pipe 30 connected to the inlet of each gas-liquid mixing device 50. The injection valve 31 is used to control the passage of brine. The bottom of the pure gas comparison cover 20 is connected to the plunger pump 42 via a gas supply pipe 40. An intake valve 43 is provided on the gas supply pipe 40 connected to the bottom of the pure gas comparison cover 20. The above-mentioned intake valves 43 are used to control the conduction of carbon dioxide gas. The plunger pump 42 is connected to a carbon dioxide gas source tank 41. The carbon dioxide gas source tank 41 is used to provide carbon dioxide gas. The tops of the formation comparison covers 10 and the pure gas comparison cover 20 are provided with sealable liquid inlets 90. Sampling pipes 70 and gas outlet pipes 80 are provided on the formation comparison covers 10 and the pure gas comparison cover 20. A sampling valve 71 is provided on the sampling pipe 70. The sampling valve 71 is used to start and stop the sampling process. Sampling bottles 72 are placed opposite to the outlets of the sampling pipes 70. An outlet valve 81 is provided on the gas outlet pipe 80. The outlet valve 81 is used to start and stop the gas release process to adjust the pressure inside the cover. Sensors for monitoring corresponding monitoring indicators are installed on the formation comparison covers 10 and the pure gas comparison cover 20. The sensors corresponding to different monitoring indicators are different. For example, a pH sensor needs to be set to monitor the pH value, and so on. Among them: three formation comparison covers 10 are respectively used to contain formation water, a preparation liquid simulating the composition of formation water, and deionized water (distilled water). The pure gas comparison cover 20 is used to contain deionized water (distilled water). The liquid supply pipe 30 is used to inject brine reflecting the situation of formation water during CO 2 leakage. The gas supply pipe 40 is used to inject CO 2 gas. The plunger pump 42 is used to control the 2 injection flow rate and flow rate of CO. The gas-liquid mixing device 50 is used to control the mixing of brine and CO 2The mixing ratio of the gas, and the gas-liquid ratio can be 2:1, 1:1, 1:2, etc., without limitation. The gas-liquid mixing device 50 is a conventional device.

[0033] Furthermore, in step 4), at a set reaction time point (such as 0 hours, 1 hour, 4 hours, 24 hours, 48 hours, etc.) after injecting brine and carbon dioxide gas into each formation comparison chamber 10 and injecting carbon dioxide gas into the pure gas comparison chamber 20, samples are taken through the sampling valve 71 and subjected to a full analysis test to obtain CO 2 The influence degrees on formation water, prepared liquid, and deionized water under different monitoring indicators, so as to obtain CO 2 The influence mechanism of leakage on different media, which is used to screen out several monitoring indicators from all monitoring indicators affecting the groundwater environment as sensitive monitoring indicators. Among them, the pure gas comparison chamber 20 is used to compare with the reaction occurring in the formation comparison chamber 10 filled with deionized water. Only pure CO 2 in the pure gas comparison chamber 20 reacts with deionized water (distilled water), and the reaction elements are single, which is suitable as a control. The formation comparison chamber 10 is used to simulate the reaction scenario of CO 2 carrying brine with different media.

[0034] Specifically, the experimental process is as follows Figure 1 , respectively pour formation water, prepared liquid prepared according to a predetermined ratio to simulate the composition of formation water, and deionized water into the three formation comparison chambers 10 from the liquid inlet 90, and pour deionized water into the pure gas comparison chamber 20 from the sealable liquid inlet 90, and then seal the liquid inlet 90. Adjust the gas-liquid mixing ratio of the gas-liquid mixing device 50, then inject brine and carbon dioxide gas into each formation comparison chamber 10, inject carbon dioxide gas into the pure gas comparison chamber 20, and then at a set reaction time point (such as 0h, 1h, 4h, 24h, 48h, etc.) take samples through the sampling valve 71 for a full analysis test to obtain CO 2 The influence on formation water, prepared liquid, and deionized water under different monitoring indicators (such as pH value, redox potential, total dissolved solids, etc.). Throughout the process, the pure gas comparison chamber 20 is used to compare with the reaction occurring in the formation comparison chamber 10 filled with deionized water. Thus, the influence mechanism of the leaked CO 2 on different media can be obtained. Various types of sensors installed on the formation comparison chamber 10 and the pure gas comparison chamber 20 respectively monitor their corresponding monitoring indicators and feedback the monitoring results to the control device (including the processor).

[0035] Then, different gas-liquid mixing ratios can be set (such as gas-liquid ratios of 2:1, 1:1, 1:2, etc.), and the experiment can be repeated many times according to the above process. The control device can screen out several sensitive monitoring indicators from all monitoring indicators affecting the groundwater environment as sensitive monitoring indicators based on the obtained monitoring results.

[0036] In actual implementation, the impact on groundwater is generally reflected through monitoring indicators such as water quality, physical and chemical parameters, water chemical components, harmful elements, and gas phase components, and sensitive monitoring indicators are then selected from these monitoring indicators.

[0037] Here, sensitive monitoring indicators refer to indicators that can sensitively reflect monitoring results from a certain angle, which can be significant changes in monitoring data, rapid feedback of monitoring data, outstanding impact on the medium, and no drift interference. In short, sensitive monitoring indicators should be able to quickly, intuitively and accurately reflect the impact on groundwater.

[0038] In practice, how to prepare the prepared solution is a well-known technique. 2 The degree of influence on different media and the process of the influence mechanism are well-known technologies in the art. The comparative analysis process of different media is slightly different and will not be described in detail here.

[0039] In practice, the experimental device can conduct multiple batches of experiments, and the experimental results are used for real-time comparison to facilitate intuitive observation of CO under different monitoring indicators. 2 The influence degree on different media, thus obtaining CO 2 The impact mechanism of leakage on different media is used to accurately screen out sensitive monitoring indicators.

[0040] Here, different media refer to the media involved in formation water, preparation fluid and deionized water, CO 2 The mechanism of leakage affecting different media refers to the way or path of carbon dioxide gas affecting various media contained in the formation.

[0041] In actual implementation, in step 4), when no wells such as wellbores such as wells and springs can be found in the monitoring area to obtain real formation water, the water quality indicators (such as mineralization, ions, etc.) of the formation water in the monitoring area are found out by collecting literature and other materials, and a preparation liquid for simulating the actual situation of the formation water is artificially prepared, wherein one of the formation comparison covers 10 is empty, and the above-mentioned CO is carried out through the other two formation comparison covers 10 and a pure gas comparison cover 20. 2 -H 2 O reaction experiment.

[0042] In step 5), when screening the actual monitoring indicators from the sensitive monitoring indicators, factors such as whether it can be implemented in the monitoring area, whether monitoring equipment and environmental factors adapted to the actual monitoring indicators can be found should be considered.

[0043] In actual implementation, some actual monitoring indicators can be directly measured by monitoring equipment, such as pH value, conductivity, TDS in water, redox potential, carbon dioxide concentration in water, etc. For some actual monitoring indicators that cannot be directly obtained by monitoring equipment, they are obtained through sampling by monitoring equipment and then tested and analyzed in the laboratory, such as physical and chemical parameters, water chemical components, gas components, toxicological indicators, etc.

[0044] In step 7), the monitoring center constructs a monitoring and early warning platform. The monitoring and early warning platform can include efficient storage of monitoring data, processing and analysis of monitoring data, trend analysis and prediction, and API interaction services. Among them, the monitoring equipment in the core area adopts online monitoring, and the monitoring equipment in the outlying area adopts online monitoring supplemented by manual inspection.

[0045] The advantages of the present invention are:

[0046] The present invention provides a way to make a real, objective and real-time evaluation of the impact of carbon dioxide leakage on the groundwater environment in carbon sequestration projects. The key lies in that the evaluation results can truly reflect the objective situation and are real-time. Specifically, the present invention considers from the mechanism of the impact of CO 2 leakage on the groundwater environment, and screens out sensitive monitoring indicators from the influencing factors such as the water quality, physical and chemical parameters, water chemical components, harmful elements, gas components, etc. of the groundwater through the CO 2 -H 2 O reaction experiment, further optimizes the actual monitoring indicators considering the applicability of the monitoring area, selects the most suitable monitoring equipment based on the actual monitoring indicators to conduct real-time monitoring of the monitoring points, and constructs a monitoring and early warning platform based on the Internet of Things, providing a favorable guarantee for timely evaluating the impact of CO 2 leakage on the groundwater environment.

[0047] The above is the preferred embodiment of the present invention and the technical principles applied. For those skilled in the art, any obvious changes such as equivalent transformation and simple replacement based on the technical solution of the present invention without departing from the spirit and scope of the present invention shall fall within the protection scope of the present invention.

Claims

1. A method for assessing the impact of carbon dioxide leakage on groundwater environment in a carbon sequestration project, characterized in that: Includes steps: 1) Determine a monitoring area according to the site conditions and geological conditions of the carbon sequestration project implementation area, wherein the monitoring area is located within the carbon sequestration project implementation area, and the monitoring area includes a core area and an epitaxial area, wherein the core area is within the epitaxial area and the epitaxial area is much larger than the core area; 2) Conduct risk point surveys within the monitoring area, and identify potential CO2 leakage risk points as monitoring points based on geological data, geophysical data, drilling data, logging data, and rock and water sample test data, combined with actual field exploration conditions; 3) Determine the background value data of groundwater quality representing the implementation area of ​​the carbon sequestration project through on-site water quality rapid testing, on-site simple experimental testing and laboratory water quality full analysis testing in the monitoring area, so as to determine the monitoring baseline for comparison with the monitoring data obtained after CO2 injection; 4) Conducting a CO2-H2O reaction experiment on the corresponding formation water, deionized water, and prepared liquid of simulated formation water components that can be obtained in the monitoring area through an experimental device, to learn the degree of influence of CO2 on different media under different monitoring indicators, to obtain the influence mechanism of CO2 leakage on different media, and then to screen out sensitive monitoring indicators from all the monitoring indicators that affect the groundwater environment; 5) In combination with the site conditions and geological conditions of the monitoring area, actual monitoring indicators suitable for the monitoring area are selected from all the sensitive monitoring indicators, and monitoring equipment of suitable type is found for each of the actual monitoring indicators; 6) According to the site conditions and geological conditions of the monitoring points, the model and specifications of the monitoring equipment used to monitor the actual monitoring indicators corresponding to the monitoring points are clearly defined for each monitoring point, wherein the dangerous threshold of CO2 leakage and the upper limit corresponding to each actual monitoring indicator are set. When the dangerous threshold or the upper limit is exceeded, it indicates that harm will be caused to the human body, thereby issuing a hazard alarm and persuading people to move away; 7) After CO2 is injected into the carbon sequestration project implementation area, the corresponding monitoring equipment is deployed at each monitoring point, and each monitoring equipment communicates with the monitoring center through the Internet of Things, wherein the monitoring data obtained by the monitoring equipment is compared with the monitoring baseline to determine whether CO2 leakage occurs and the impact of CO2 leakage on the groundwater environment, so as to objectively evaluate the impact of CO2 leakage on the groundwater environment in the monitoring area in real time.

2. The method for assessing the impact of carbon dioxide leakage on groundwater environment in a carbon sequestration project according to claim 1, characterized in that: In the step 3), the background value data is groundwater data obtained for the monitoring area before CO2 injection, and the background value data is measured through a wellbore.

3. The method for assessing the impact of carbon dioxide leakage on groundwater environment in a carbon sequestration project according to claim 1, characterized in that: In the step 4), the experimental device includes four fully sealed pressure-resistant organic glass covers arranged side by side, three of which are used as formation comparison covers, and the remaining one is used as a pure gas comparison cover. The bottom of each formation comparison cover is connected to an outlet of a gas-liquid mixing device via an injection pipe, and each injection pipe is provided with a control valve. The inlet of each gas-liquid mixing device is divided into two paths, one of which is connected to a plunger pump via an air supply pipe, and an air intake valve is provided on the air supply pipe connected to the inlet of each gas-liquid mixing device, and the other is connected to a liquid supply device via a liquid supply pipe, and a liquid injection valve is provided on the liquid supply pipe connected to the inlet of each gas-liquid mixing device. The bottom of the pure gas comparison cover is connected to the plunger pump via the air supply pipe, and the air intake valve is provided on the air supply pipe connected to the bottom of the pure gas comparison cover. The plunger pump is connected to the carbon dioxide The formation comparison cover and the pure gas comparison cover are connected to a carbon gas source tank, and a sealable liquid inlet is provided on the top of the formation comparison cover and the pure gas comparison cover, and a sampling tube and an air outlet pipe are provided on the formation comparison cover and the pure gas comparison cover, and a sampling valve is provided on the sampling tube, and a sampling bottle is placed opposite to the outlet of the sampling tube, and an air outlet valve is provided on the air outlet pipe, and sensors for monitoring the corresponding monitoring indicators are installed on the formation comparison cover and the pure gas comparison cover, wherein: the three formation comparison covers are respectively used to hold formation water, a prepared liquid simulating the components of formation water, and deionized water, the pure gas comparison cover is used to hold deionized water, the liquid supply pipe is used to inject brine, the air supply pipe is used to inject CO2 gas, the plunger pump is used to control the flow rate and flow of carbon dioxide injection, and the gas-liquid mixing device is used to control the mixing ratio of brine and CO2 gas.

4. The method for assessing the impact of carbon dioxide leakage on groundwater environment in a carbon sequestration project as claimed in claim 3, characterized in that: In the step 4), at the set reaction time point after injecting brine and carbon dioxide gas into each of the formation comparison covers and injecting carbon dioxide gas into the pure gas comparison cover, sampling is performed through a sampling valve and a full analysis test is performed to obtain the degree of influence of CO2 on formation water, preparation liquid and deionized water under different monitoring indicators, thereby obtaining the influence mechanism of CO2 leakage on different media, which is used to screen out several monitoring indicators from all the monitoring indicators affecting the groundwater environment as the sensitive monitoring indicators, wherein the pure gas comparison cover is used to compare with the reaction of the formation comparison cover containing deionized water.

5. The method for assessing the impact of carbon dioxide leakage on groundwater environment in a carbon sequestration project as claimed in claim 4, characterized in that: In the step 4), when no wellbore is found in the monitoring area to obtain formation water, the water quality indicators of the formation water in the monitoring area are ascertained by collecting data, and a preparation liquid is artificially prepared to simulate the actual situation of the formation water, wherein one of the formation comparison covers is empty, and the CO2-H2O reaction experiment is carried out through the other two formation comparison covers and one pure gas comparison cover.

6. The method for assessing the impact of carbon dioxide leakage on groundwater environment in a carbon sequestration project according to claim 1, characterized in that: In the step 5), the actual monitoring indicators are screened from the sensitive monitoring indicators based on whether they can be implemented in the monitoring area, whether monitoring equipment and environmental factors that are compatible with the actual monitoring indicators can be found.

7. The method for assessing the impact of carbon dioxide leakage on groundwater environment in a carbon sequestration project according to claim 1, characterized in that: A portion of the actual monitoring indicators are directly measured by the monitoring equipment, and another portion of the actual monitoring indicators that cannot be directly obtained by the monitoring equipment are obtained after sampling by the monitoring equipment and testing and analysis in the laboratory.

8. The method for assessing the impact of carbon dioxide leakage on groundwater environment in a carbon sequestration project as claimed in claim 1, characterized in that: In step 7), the monitoring center constructs a monitoring and early warning platform, which includes efficient storage of monitoring data, monitoring data processing and analysis, trend analysis and prediction, and API interactive service business. Among them, the monitoring equipment in the core area adopts online monitoring, and the monitoring equipment in the extended area adopts manual inspection in addition to online monitoring.

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