Experimental device and method for simulating CO2 geological sequestration shallow surface environment monitoring model

Abstract

The invention discloses an experimental device and method for simulating a CO2 geological sequestration shallow surface environment monitoring model. The experimental device for simulating the CO2 geological sequestration shallow surface environment monitoring model comprises a stratum unit, a CO2 injection unit and a data acquisition and control unit, the CO2 injection unit is connected with the stratum unit, and the data acquisition and control unit is respectively connected with the CO2 injection unit and the stratum unit. The experimental device for simulating the CO2 geological sequestration shallow earth surface environment monitoring model is simple in structure and convenient to use, the experimental process can be visually observed, the situation that CO2 leaks to the earth surface can be truly restored, and the CO2 volume fraction can be calculated according to the permissible range of the CO2 content in soil by establishing the corresponding relation between the CO2 volume fraction and each monitoring parameter index. Therefore, the early warning value and the safety limit of each monitoring parameter index are determined.

Description

Technical Field

[0001] The present invention relates to the technical field of geological simulation research, and particularly to an experimental device and method for simulating an experimental device and method for monitoring the shallow surface environment of CO2 geological storage. Background Art

[0002] Geological sequestration of carbon dioxide is an important technology that has received significant attention in current geological research. However, due to the large injection volume, there is a risk of leakage in the CO2 geological storage site. Therefore, conducting leakage monitoring of the CO2 storage site is crucial for ensuring environmental safety, assessing project risks, and protecting public health. Among them, by monitoring the leakage of CO2 on the ground surface, potential environmental pollution and ecological damage can be detected and prevented in a timely manner, thereby protecting soil, water sources, and biodiversity from damage. In addition, the monitoring data provides a scientific basis for evaluating the long-term stability and safety of the sequestration project, helping to optimize the sequestration technology and improve the sequestration efficiency. Therefore, monitoring the shallow surface environment of CO2 geological storage is a key link in achieving sustainable environmental management.

[0003] Generally speaking, the monitoring indicators of the shallow surface environment of CO2 geological storage mainly focus on groundwater and subsurface soil. The dynamic changes in the quality of shallow groundwater are mainly monitored, and the changes in the CO2 flux of the shallow surface are mainly monitored in the subsurface soil. In the CO2 geological storage project, groundwater sampling and detection, as well as CO2 flux monitoring, are carried out to identify whether CO2 leaks and the degree of pollution to the shallow surface environment. However, the current challenge lies in how to accurately evaluate the CO2 leakage volume and leakage degree through the changes in the quality of shallow surface groundwater and CO2 flux. There is currently a lack of relevant standards and basis for determining the warning values and safety limit ranges of these parameters.

[0004] To overcome this problem, it is particularly crucial to conduct model experiments on shallow subsurface CO2 leakage. Existing technologies such as patent number (CN201820553331.1) disclose an artificial control simulation device for CO2 geological storage leakage. By introducing CO2 at different rates and fluxes into the soil chamber, different leakage amounts and scenarios of CO2 are simulated, and the impact of CO2 leakage on the surface environment is judged by observing the growth status of surface plants. However, on the one hand, this method ignores the impact of CO2 leakage on groundwater quality. On the other hand, the evaluation of plant growth status is affected by human subjective factors, lacking quantitative evaluation indicators, and the plant growth feedback requires a certain time period, resulting in a certain time lag. Therefore, it cannot provide a reference for determining the warning values and safety boundaries of monitoring indicators and parameters of groundwater and soil gas. In order to more realistically simulate the actual ground situation, it is necessary to comprehensively consider the impact of CO2 leakage on groundwater and soil gas, and through quantitative monitoring of groundwater quality and soil gas flux under different CO2 leakage amounts, provide a scientific basis for determining the warning values and safety boundaries of relevant monitoring indicators of groundwater and soil gas.

[0005] Therefore, there is an urgent need for an experimental device or method that can simultaneously comprehensively consider the impact of CO2 leakage on groundwater and soil gas to simulate the shallow subsurface environmental monitoring model of CO2 geological storage. Summary of the Invention

[0006] In view of the above problems, an experimental device and method for simulating a shallow subsurface environmental monitoring model of CO2 geological storage are provided to overcome the above problems or at least partially solve the above problems.

[0007] Other features and advantages of the present invention will become apparent through the following detailed description, or be learned in part through the practice of the present invention.

[0008] According to the first aspect of an embodiment of the present invention, an experimental device for simulating a shallow subsurface environmental monitoring model of CO2 geological storage is provided. The experimental device for simulating a shallow subsurface environmental monitoring model of CO2 geological storage includes: a formation unit, a CO2 injection unit, and a data acquisition and control unit; the CO2 injection unit is connected to the formation unit, and the data acquisition and control unit is respectively connected to the CO2 injection unit and the formation unit; The CO2 injection unit is used to inject CO2 gas into the formation unit; The formation unit is used to simulate shallow subsurface soil and groundwater; The data acquisition and control unit is used to control the injection volume of the CO2 injection unit, set the target CO2 volume fraction, collect and measure various monitoring parameter indicators from the formation unit. The monitoring parameter indicators include CO2 flux, groundwater pH value, cation concentration, ionic contents of carbonate and bicarbonate, and conductivity, establish the corresponding relationship between the CO2 volume fraction and each monitoring parameter indicator, and determine the warning values and safety limits of each monitoring parameter indicator according to the allowable range of CO2 content in the soil.

[0009] In some embodiments of the present invention, the formation unit includes a glass sand-filled box, a CO2 gas chamber, a semi-permeable membrane, a shallow formation soil simulation layer and a groundwater simulation layer. Among them, the CO2 gas chamber, the semi-permeable membrane, the shallow formation soil simulation layer and the groundwater simulation layer are all arranged in the glass sand-filled box. A through hole is opened on the side surface of the glass sand-filled box corresponding to the area of the CO2 gas chamber, and the CO2 gas chamber is communicated with the CO2 injection unit through the through hole; the CO2 gas chamber is located at the lowermost part of the glass sand-filled box, the shallow formation soil simulation layer is arranged above the CO2 gas chamber, and the CO2 gas chamber and the shallow formation soil simulation layer are separated by a semi-permeable membrane, and a groundwater simulation layer is deposited at the bottom of the shallow formation soil simulation layer close to the semi-permeable membrane.

[0010] In some embodiments of the present invention, the CO2 injection unit includes a CO2 gas cylinder, an injection conduit and a solenoid valve. The CO2 gas cylinder is communicated with the through hole of the glass sand-filled box through the injection conduit, a solenoid valve is arranged on the injection conduit, and the solenoid valve is electrically connected to the data acquisition and control unit.

[0011] In some embodiments of the present invention, a pressure reducing valve is further arranged on the injection conduit.

[0012] In some embodiments of the present invention, the data acquisition and control unit includes a fluid-fidelity sampling device and a data acquisition and recording system. The fluid-fidelity sampling device is arranged in the shallow formation soil simulation layer, and the lower half of the fluid-fidelity sampling device is buried into the groundwater simulation layer; the solenoid valve is electrically connected to the data acquisition and recording system.

[0013] In some embodiments of the present invention, the data acquisition and control unit includes a CO2 flux meter. The CO2 flux meter is arranged on the upper part of the shallow formation soil simulation layer and is buried into the shallow formation soil simulation layer at a predetermined distance. The CO2 flux meter is electrically connected to the data acquisition and recording system.

[0014] In some embodiments of the present invention, the predetermined distance is 5-7 cm.

[0015] In some embodiments of the present invention, the data acquisition and control unit includes a pH sensor, which is buried inside the groundwater simulation layer at the bottom of the shallow subsurface soil simulation layer, and the pH sensor is electrically connected to the data acquisition and recording system.

[0016] In some embodiments of the present invention, the data acquisition and control unit includes a CO2 controller and a CO2 sensor. The CO2 sensor is buried in the shallow subsurface soil simulation layer, above the groundwater simulation layer, and the CO2 controller is electrically connected to the data acquisition and recording system and the CO2 sensor respectively.

[0017] According to the second aspect of the embodiments of the present invention, an experimental method for simulating a shallow surface environment monitoring model of CO2 geological sequestration is provided. The experimental method for simulating a shallow surface environment monitoring model of CO2 geological sequestration includes the following steps: S1. Set the target CO2 volume fraction of the CO2 controller through the data acquisition and recording system, and the solenoid valve remains open. S2. Open the CO2 gas cylinder and the pressure reducing valve to reduce the pressure of the high-pressure CO2 gas after passing through the pressure reducing valve, pass through the solenoid valve, and enter the CO2 gas chamber through the gas injection conduit. A part of the high-concentration CO2 gas contained in the CO2 gas chamber dissolves in the groundwater simulation layer after passing through the semipermeable membrane, and the other part remains free in the shallow subsurface soil simulation layer. S3. The CO2 sensor continuously monitors the CO2 volume fraction in the shallow subsurface soil simulation layer. When the monitored CO2 volume fraction reaches the target CO2 volume fraction, the CO2 controller will send a closing instruction to the solenoid valve through the data acquisition and recording system, and at this time, no more CO2 gas is injected into the CO2 gas chamber. S4. Measure and obtain each monitoring parameter index. The monitoring parameter indexes include CO2 flux, groundwater pH value, cation concentration, carbonate ion content, bicarbonate ion content, and conductivity. Among them, measure the CO2 flux in the shallow subsurface soil simulation layer through a CO2 flux meter, and record the CO2 flux value at the target CO2 volume fraction through the data acquisition and recording system; sample the groundwater simulation layer through a fluid-fidelity sampling device to collect and obtain the cation concentration, carbonate ion content, bicarbonate ion content, and conductivity in the groundwater simulation layer; measure the groundwater pH value in the groundwater simulation layer in real time through a pH sensor and record it through the data acquisition and recording system; after the above measurements are completed, close the CO2 gas cylinder and the pressure reducing valve to complete a parameter value measurement experiment at the target CO2 volume fraction and obtain the experimental results. S5. According to the above experimental results, draw the relationship diagrams of CO2 volume fraction with CO2 flux, groundwater pH value, cation concentration, carbonate ion content, bicarbonate ion content, and conductivity respectively, establish the corresponding relationship between CO2 volume fraction and each monitoring parameter index, and determine the warning values and safety limits of each monitoring parameter index according to the allowable range of CO2 content in the soil.

[0018] The technical solutions provided in the embodiments of the present invention have at least the following technical effects or advantages: The experimental device and method for the simulation of the shallow surface environment monitoring model for CO2 geological storage in the embodiments of the present invention. The experimental device for the simulation of the shallow surface environment monitoring model for CO2 geological storage has a simple structure and is convenient to use. It can visually observe the experimental process and truly restore the situation of CO2 leakage to the surface. By establishing the corresponding relationship between CO2 volume fraction and each monitoring parameter index, and according to the allowable range of CO2 content in the soil, the warning values and safety limits of each monitoring parameter index are determined, which helps to establish a complete set of shallow surface CO2 leakage monitoring index systems and monitoring systems, and standardize the environmental monitoring content of CO2 geological storage projects.

[0019] The above description is only an overview of the technical solutions of the present invention. In order to be able to understand the technical means of the present invention more clearly, it can be implemented according to the content of the specification. And in order to make the above and other purposes, features and advantages of the present invention more obvious and understandable, the following specifically gives the specific embodiments of the present invention. Description of the Drawings

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required to be used in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained according to these drawings without creative efforts.

[0021] Figure 1 It is a schematic diagram of the principle structure of an experimental device for a simulation of a shallow surface environment monitoring model for CO2 geological storage provided by an embodiment of the present invention; Figure 2 It is a schematic diagram of the corresponding relationship between CO2 volume fraction and CO2 flux in a preferred embodiment of the present invention; Figure 3 It is a schematic diagram of the corresponding relationship between CO2 volume fraction and pH in a preferred embodiment of the present invention; Figure 4 It is a schematic diagram of the corresponding relationship between CO2 volume fraction and conductivity in a preferred embodiment of the present invention; Figure 5 It is a schematic diagram of the corresponding relationship between CO2 volume fraction and bicarbonate ion in a preferred embodiment of the present invention.

[0022] Description of the reference numerals: 1. CO2 gas cylinder; 2. Pressure reducing valve; 3. Gas injection conduit; 4. Solenoid valve; 5. CO2 controller; 6. Data acquisition and recording system; 7. CO2 fluxmeter; 8. pH sensor; 9. Fluid fidelity sampling device; 10. Glass sand-filled box; 11. Semipermeable membrane; 12. CO2 gas chamber; 13. Groundwater simulation layer; 14. CO2 sensor; 15. Shallow formation soil simulation layer. Detailed implementation manners

[0023] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings.

[0024] Various schematic structural diagrams according to the embodiments of the present disclosure are shown in the accompanying drawings. These figures are not drawn to scale, where for the purpose of clear expression, some details are enlarged and some details may be omitted. The shapes of various regions and layers shown in the figures, as well as their relative sizes and positional relationships, are merely exemplary, and may deviate in practice due to manufacturing tolerances or technical limitations. Those skilled in the art can additionally design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0025] In the context of the present disclosure, when a layer / element is referred to as being "on" another layer / element, the layer / element can be directly on the other layer / element, or there can be an intermediate layer / element between them. Additionally, if a layer / element is "on" another layer / element in one orientation, then when the orientation is reversed, the layer / element can be "under" the other layer / element. In the context of the present disclosure, similar or identical components may be denoted by the same or similar reference numerals.

[0026] To better understand the above technical solutions, the above technical solutions will be described in detail below in combination with specific implementation manners. It should be understood that the embodiments of the present disclosure and the specific features in the embodiments are detailed descriptions of the technical solutions of the present invention, rather than limitations on the technical solutions of the present invention. Without conflict, the technical features in the embodiments of the present invention and the embodiments can be combined with each other.

[0027] The experimental device of the simulated CO2 geological storage shallow surface environment monitoring model according to the embodiment of the present invention includes: a formation unit, a CO2 injection unit, and a data acquisition and control unit; the CO2 injection unit is connected to the formation unit, and the data acquisition and control unit is respectively connected to the CO2 injection unit and the formation unit; the CO2 injection unit is used to inject CO2 gas into the formation unit; the formation unit is used to simulate shallow formation soil and groundwater; the data acquisition and control unit is used to control the injection volume of the CO2 injection unit, set the target CO2 volume fraction, and collect and measure various monitoring parameter indicators from the formation unit. The monitoring parameter indicators include CO2 flux, groundwater pH value, cation concentration, carbonate, bicarbonate ion content, conductivity, and establish the corresponding relationship between the CO2 volume fraction and each monitoring parameter indicator, and determine the warning value and safety limit of each monitoring parameter indicator according to the allowable range of CO2 content in the soil.

[0028] Figure 1 It is a schematic diagram of the principle structure of an experimental device for a simulated CO2 geological storage shallow surface environment monitoring model provided by an embodiment of the present invention, as Figure 1 shown. In the embodiment of the present invention, the formation unit includes a glass sand-filled box 10, a CO2 gas chamber 12, a semi-permeable membrane 11, a shallow formation soil simulation layer 15, and a groundwater simulation layer 13. Among them, the CO2 gas chamber 12, the semi-permeable membrane 11, the shallow formation soil simulation layer 15, and the groundwater simulation layer 13 are all arranged in the glass sand-filled box 10. A through hole is opened in the side surface of the glass sand-filled box 10 corresponding to the area of the CO2 gas chamber 12, and the CO2 gas chamber 12 is communicated with the CO2 injection unit through the through hole; the CO2 gas chamber 12 is located at the bottom of the glass sand-filled box 10, and the shallow formation soil simulation layer 15 is arranged above the CO2 gas chamber 12, and the CO2 gas chamber 12 is separated from the shallow formation soil simulation layer 15 by a semi-permeable membrane 11. The groundwater simulation layer 13 is deposited at the bottom of the shallow formation soil simulation layer 15 close to the semi-permeable membrane 11; the glass sand-filled box 10 is fully transparent, which is convenient for the intuitive observation of the whole process of the CO2 leakage process; the shallow formation soil simulation layer 15 is used to simulate the shallow formation soil environment; the groundwater simulation layer 13 is used to simulate the groundwater environment.

[0029] In the embodiment of the present invention, the CO2 injection unit includes a CO2 gas cylinder 1, an injection conduit 3, and a solenoid valve 4. The CO2 gas cylinder 1 is communicated with the through hole of the glass sand-filled box 10 through the injection conduit 3. The solenoid valve 4 is arranged on the injection conduit 3, and the solenoid valve 4 is electrically connected to the data acquisition and control unit; under the control of the data acquisition and control unit, by controlling the opening and closing of the solenoid valve 4, the quantitative control of the CO2 gas injection volume is realized.

[0030] In an embodiment of the present invention, a pressure reducing valve 2 is further provided on the gas injection conduit 3. The pressure reducing valve 2 is used to reduce the pressure of the high-pressure CO2 gas in the CO2 gas cylinder 1 when it is output, avoiding accidents caused by direct contact with the solenoid valve 4 during its rapid output, and improving safety.

[0031] In an embodiment of the present invention, the data acquisition and control unit includes a fluid fidelity sampling device 9 and a data acquisition and recording system 6. The fluid fidelity sampling device 9 is disposed in the shallow formation soil simulation layer 15, and the lower half of the fluid fidelity sampling device 9 is buried into the groundwater simulation layer 13; the solenoid valve 4 is electrically connected to the data acquisition and recording system 6; the fluid fidelity sampling device 9 is used to sample the groundwater simulation layer 13, collect and obtain the cation concentration, carbonate, bicarbonate ion content, and conductivity in the groundwater simulation layer 13; the data acquisition and recording system 6 is used to store and record the volume fractions of each target CO2 and each monitoring parameter index, and simultaneously establish the corresponding relationship between the CO2 volume fraction and each monitoring parameter index. According to the allowable range of CO2 content in the soil, the warning values and safety limits of each monitoring parameter index are determined. The data acquisition and recording system 6 can be a terminal device such as a PC, a local server, or a cloud server.

[0032] Refer to Figures 2-5 as shown Figure 2 It is a schematic diagram of the corresponding relationship between the CO2 volume fraction and the CO2 flux in a preferred embodiment of the present invention. Figure 3 It is a schematic diagram of the corresponding relationship between the CO2 volume fraction and the pH in a preferred embodiment of the present invention. Figure 4 It is a schematic diagram of the corresponding relationship between the CO2 volume fraction and the conductivity in a preferred embodiment of the present invention. Figure 5 It is a schematic diagram of the corresponding relationship between the CO2 volume fraction and the bicarbonate in a preferred embodiment of the present invention.

[0033] In an embodiment of the present invention, the data acquisition and control unit includes a CO2 fluxmeter 7. The CO2 fluxmeter 7 is disposed on the upper part of the shallow formation soil simulation layer 15 and is buried into the shallow formation soil simulation layer 15 at a predetermined distance. The CO2 fluxmeter 7 is electrically connected to the data acquisition and recording system 6; the CO2 fluxmeter 7 is used to measure the CO2 flux in the shallow formation soil simulation layer 15.

[0034] In an embodiment of the present invention, the predetermined distance is 5-7 cm. In other embodiments of the present invention, according to the actual size of the glass sand-filled box 10 or the experimental requirements, the predetermined distance can also be other numerical ranges, and the embodiments of the present invention are not limited thereto.

[0035] In an embodiment of the present invention, the data acquisition and control unit includes a pH sensor 8, and the pH sensor 8 is buried inside a groundwater simulation layer 13 at the bottom of a shallow subsurface soil simulation layer 15. The pH sensor 8 is electrically connected to the data acquisition and recording system 6; the pH sensor 8 is used for measuring the pH value of the groundwater in the groundwater simulation layer 13 in real time.

[0036] In an embodiment of the present invention, the data acquisition and control unit includes a CO2 controller 5 and a CO2 sensor 14. The CO2 sensor 14 is buried in the shallow subsurface soil simulation layer 15 and is located above the groundwater simulation layer 13. The CO2 controller 5 is electrically connected to the data acquisition and recording system 6 and the CO2 sensor 14 respectively; the CO2 controller 5 is used for setting a target CO2 volume fraction, and the CO2 sensor 14 is used for monitoring the CO2 volume fraction in the shallow subsurface soil simulation layer 15 in real time.

[0037] The experimental device of the simulation CO2 geological sequestration shallow surface environment monitoring model according to the embodiment of the present invention simulates the CO2 geological sequestration shallow surface environment monitoring model by allowing high-concentration CO2 in the CO2 chamber 12 to penetrate through the semi-permeable membrane 11 into the groundwater simulation layer 13 and the shallow subsurface soil simulation layer 15. Compared with the prior art, it has the following advantages: 1. The device has the characteristics of simple structure and convenient use. A glass sand-filled box 10 made of colorless transparent high-pressure glass tube is used to simulate the wellbore, and the whole process of CO2 leakage can be visually observed, which has reference value for understanding the whole process of CO2 leakage; 2. The present invention can simultaneously consider the influence of CO2 leakage on groundwater and soil, and more truly reflect the situation of the shallow surface stratum. By setting a semi-permeable membrane 11 between the shallow subsurface soil simulation layer 15 and the CO2 chamber 12, the semi-permeable membrane 11 has the function of permeable to gas but impermeable to water, which can realize the penetration of high-concentration CO2 gas into the shallow subsurface soil simulation layer 15 and the groundwater simulation layer 13, but can isolate groundwater from entering the CO2 chamber 12, so as to realize the slow leakage of CO2 into groundwater, and then through groundwater leakage into the shallow soil to the shallow soil and groundwater. This way can truly restore the situation of CO2 leakage to the surface.

[0038] 3. The monitoring parameters of the present invention are completely consistent with the monitoring indexes of real CO2 geological sequestration projects, and can quickly carry out parameter index monitoring under different CO2 leakage scenarios. Compared with the qualitative judgment through the plant growth state, this way has the advantages of rapid response, quick response, and can provide direct parameter guidance for the on-site monitoring plan.

[0039] 4. Since the CO2 leakage volume cannot be directly monitored at a real CO2 geological storage site, the CO2 controller 5, the CO2 sensor 14 buried in the soil, and the solenoid valve 4 of the present invention can be used to control different CO2 volume fraction values in the shallow formation soil simulation layer 15. This method has direct operability for actual projects and has more reference value.

[0040] 5. It can be used to conduct monitoring experiments on CO2 flux, formation water pH, ion concentration, and conductivity in the soil under different CO2 volume fractions, and conduct shallow surface environment monitoring experiments under different target CO2 volume fractions, so as to establish a quantitative relationship between the CO2 volume fraction in the soil and CO2 flux, groundwater pH value, cation concentration, carbonate, bicarbonate ion content, and conductivity. According to the allowable content concentration range of CO2 in the soil, the warning values and safety limits of each monitoring parameter can be determined; the results can be directly used to guide and reference the on-site monitoring work of the CO2 geological storage site, providing basic parameter basis for the operation and reference of the monitoring work; it can be used to quantitatively evaluate the impact of CO2 leakage degree on the monitoring parameters, provide data support for the setting of warning values of monitoring parameters such as CO2 flux, groundwater pH, and water ion concentration, and help to establish a complete set of shallow surface CO2 leakage monitoring index systems and monitoring systems, and provide scientific basis for standardizing the environmental monitoring content work of CO2 geological storage projects.

[0041] Based on the above embodiments, as an implementation of the above Figure 1 shown device, the present invention provides an embodiment of an experimental method for simulating a shallow surface environment monitoring model of CO2 geological storage. This method embodiment corresponds to Figure 1 the shown device embodiment. The experimental method for simulating a shallow surface environment monitoring model of CO2 geological storage includes the following steps: S1. Set the target CO2 volume fraction of the CO2 controller 5 through the data acquisition and recording system 6, and the solenoid valve 4 remains open. S2. Open the CO2 gas cylinder 1 and the pressure reducing valve 2, so that the high-pressure CO2 gas is depressurized after passing through the pressure reducing valve 2, and then enters the CO2 gas chamber 12 through the solenoid valve 4 and the injection conduit 3. The high-concentration CO2 gas contained in the CO2 gas chamber 12 passes through the semi-permeable membrane 11, and a part of it dissolves in the groundwater simulation layer 13, and the other part is free in the shallow formation soil simulation layer 15. S3. The CO2 sensor 14 continuously monitors the CO2 volume fraction in the shallow formation soil simulation layer 15. When the monitored CO2 volume fraction reaches the target CO2 volume fraction, the CO2 controller 5 will send a closing instruction to the solenoid valve 4 through the data acquisition and recording system 6. At this time, no more CO2 gas is injected into the CO2 gas chamber 12. S4. Measure and obtain each monitoring parameter index. The monitoring parameter indexes include CO2 flux, groundwater pH value, cation concentration, carbonate radical, ionic content of bicarbonate radical, and conductivity. Among them, the CO2 flux in the shallow formation soil simulation layer 15 is measured by the CO2 flux meter 7, and the CO2 flux value at the target CO2 volume fraction is recorded by the data acquisition and recording system 6; the groundwater simulation layer 13 is sampled by the fluid-fidelity sampling device 9 to collect and obtain the cation concentration, carbonate radical, ionic content of bicarbonate radical, and conductivity in the groundwater simulation layer 13; the groundwater pH value in the groundwater simulation layer 13 is measured in real time by the pH sensor 8 and recorded by the data acquisition and recording system 6; after the above measurements are completed, the CO2 gas cylinder 1 and the pressure reducing valve 2 are closed to complete a parameter value measurement experiment at the target CO2 volume fraction and obtain the experimental results. S5. According to the above experimental results, draw the relationship diagrams of CO2 volume fraction with CO2 flux, groundwater pH value, cation concentration, carbonate radical, ionic content of bicarbonate radical, and conductivity respectively, establish the corresponding relationship between CO2 volume fraction and each monitoring parameter index, and determine the warning values and safety limits of each monitoring parameter index according to the allowable range of CO2 content in the soil.

[0042] The experimental method of the simulation CO2 geological storage shallow surface environment monitoring model described in the embodiments of the present invention can be executed by the experimental device of the simulation CO2 geological storage shallow surface environment monitoring model provided in the above embodiments. The experimental method of the simulation CO2 geological storage shallow surface environment monitoring model has the corresponding functional components and beneficial effects of the experimental device of the simulation CO2 geological storage shallow surface environment monitoring model described in the above embodiments. For details, please refer to the embodiments of the experimental device of the simulation CO2 geological storage shallow surface environment monitoring model, and the embodiments of the present invention will not be elaborated here.

[0043] In the specification provided here, a large number of specific details are described. However, it can be understood that the embodiments of the present invention can be practiced without these specific details. In some instances, well-known methods, structures, and technologies are not shown in detail so as not to obscure the understanding of this specification.

[0044] Similarly, it should be understood that, for the purpose of streamlining the present disclosure and aiding in the understanding of one or more of the various inventive aspects, in the foregoing description of the exemplary embodiments of the present invention, the various features of the present invention are sometimes grouped together in a single embodiment, figure, or description thereof. However, the disclosed method should not be construed as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as reflected by the claims, the inventive aspects lie in less than all of the features of the single foregoing disclosed embodiment. Thus, the claims following the detailed description are hereby expressly incorporated into the detailed description, with each claim standing on its own as a separate embodiment of the present invention.

[0045] It should be noted that the above embodiments are illustrative of the present invention rather than limiting the present invention, and those skilled in the art can design alternative embodiments without departing from the scope of the appended claims.

Claims

1. An experimental device for simulating a shallow subsurface environmental monitoring model for CO2 geological storage, characterized in that, The experimental device of the simulated CO2 geological storage shallow surface environment monitoring model includes: a formation unit, a CO2 injection unit, and a data acquisition and control unit; the CO2 injection unit is connected to the formation unit, and the data acquisition and control unit is respectively connected to the CO2 injection unit and the formation unit; The CO2 injection unit is used to inject CO2 gas into the formation unit; The formation unit is used to simulate shallow formation soil and groundwater; The data acquisition and control unit is used to control the injection volume of the CO2 injection unit, set the target CO2 volume fraction, and collect and measure various monitoring parameter indicators from the formation unit. The monitoring parameter indicators include CO2 flux, groundwater pH value, cation concentration, carbonate, bicarbonate ion content, conductivity, and establish the corresponding relationship between the CO2 volume fraction and each monitoring parameter indicator. According to the allowable range of CO2 content in the soil, determine the warning values and safety limits of each monitoring parameter indicator.

2. The experimental device for the simulation of the shallow surface environmental monitoring model for CO2 geological storage according to claim 1, wherein: The formation unit includes a glass sand-filled box, a CO2 chamber, a semi-permeable membrane, a shallow formation soil simulation layer, and a groundwater simulation layer. The CO2 chamber, the semi-permeable membrane, the shallow formation soil simulation layer, and the groundwater simulation layer are all arranged in the glass sand-filled box. A through hole is opened on the side of the glass sand-filled box corresponding to the area of the CO2 chamber, and the CO2 chamber is communicated with the CO2 injection unit through the through hole; the CO2 chamber is located at the bottom of the glass sand-filled box, the shallow formation soil simulation layer is arranged above the CO2 chamber, and the CO2 chamber is separated from the shallow formation soil simulation layer by a semi-permeable membrane. The groundwater simulation layer is deposited at the bottom of the shallow formation soil simulation layer close to the semi-permeable membrane.

3. The experimental device of the shallow surface environment monitoring model for simulating CO2 geological storage according to claim 2, wherein: The CO2 injection unit includes a CO2 gas cylinder, an injection conduit, and a solenoid valve. The CO2 gas cylinder is communicated with the through hole of the glass sand-filled box through the injection conduit. A solenoid valve is arranged on the injection conduit, and the solenoid valve is electrically connected to the data acquisition and control unit.

4. The experimental device of the simulation CO2 geological sequestration shallow surface environment monitoring model according to claim 3, characterized in that: A pressure reducing valve is also arranged on the injection conduit.

5. The experimental device of the simulation CO2 geological sequestration shallow surface environment monitoring model according to claim 3, characterized in that: The data acquisition and control unit includes a fluid-fidelity sampling device and a data acquisition and recording system. The fluid-fidelity sampling device is arranged in the shallow formation soil simulation layer, and the lower half of the fluid-fidelity sampling device is buried into the groundwater simulation layer; the solenoid valve is electrically connected to the data acquisition and recording system.

6. The experimental device for the simulation of the shallow subsurface environmental monitoring model for CO2 geological sequestration according to claim 5, characterized in that: The data acquisition and control unit includes a CO2 flux meter. The CO2 flux meter is arranged on the upper part of the shallow formation soil simulation layer and buried into the shallow formation soil simulation layer at a predetermined distance. The CO2 flux meter is electrically connected to the data acquisition and recording system.

7. The experimental device for the simulation of the shallow surface environmental monitoring model for CO2 geological sequestration according to claim 6, characterized in that: The predetermined distance is 5-7 cm.

8. The experimental device for the simulation of the shallow surface environmental monitoring model for CO2 geological sequestration according to claim 5, characterized in that: The data acquisition and control unit includes a pH sensor. The pH sensor is buried inside the groundwater simulation layer at the bottom of the shallow formation soil simulation layer. The pH sensor is electrically connected to the data acquisition and recording system.

9. The experimental device of the simulation CO2 geological storage shallow surface environment monitoring model according to claim 5, characterized in that: The data acquisition and control unit includes a CO2 controller and a CO2 sensor. The CO2 sensor is buried in the shallow subsurface soil simulation layer, above the groundwater simulation layer. The CO2 controller is electrically connected to the data acquisition and recording system and the CO2 sensor respectively.

10. An experimental method for a shallow surface environment monitoring model of simulated CO2 geological storage, which is applied to the experimental device for the shallow surface environment monitoring model of simulated CO2 geological storage according to any one of claims 1-9, characterized in that, The experimental method for simulating the shallow surface environment monitoring model of CO2 geological storage includes the following steps: S1. Set the target CO2 volume fraction of the CO2 controller through the data acquisition and recording system, and the solenoid valve remains open. S2. Open the CO2 gas cylinder and the pressure reducing valve, so that the high-pressure CO2 gas is depressurized after passing through the pressure reducing valve, passes through the solenoid valve, and then enters the CO2 gas chamber through the injection conduit. The high-concentration CO2 gas contained in the CO2 gas chamber passes through the semi-permeable membrane, and a part of it dissolves in the groundwater simulation layer, and the other part remains free in the shallow subsurface soil simulation layer. S3. The CO2 sensor continuously monitors the CO2 volume fraction in the shallow subsurface soil simulation layer. When the monitored CO2 volume fraction reaches the target CO2 volume fraction, the CO2 controller will send a closing instruction to the solenoid valve through the data acquisition and recording system, and at this time, no more CO2 gas is injected into the CO2 gas chamber. S4. Measure and obtain each monitoring parameter index. The monitoring parameter indexes include CO2 flux, groundwater pH value, cation concentration, ionic contents of carbonate and bicarbonate, and conductivity. Among them, measure the CO2 flux in the shallow subsurface soil simulation layer with a CO2 flux meter, and record the CO2 flux value at the target CO2 volume fraction through the data acquisition and recording system; sample the groundwater simulation layer with a fluid-fidelity sampling device to collect and obtain the cation concentration, ionic contents of carbonate and bicarbonate, and conductivity in the groundwater simulation layer; measure the groundwater pH value in the groundwater simulation layer in real time with a pH sensor and record it through the data acquisition and recording system; after the above measurements are completed, close the CO2 gas cylinder and the pressure reducing valve to complete a parameter value measurement experiment at the target CO2 volume fraction and obtain the experimental results. S5. According to the above experimental results, draw the relationship diagrams of CO2 volume fraction vs. CO2 flux, groundwater pH value, cation concentration, ionic contents of carbonate and bicarbonate, and conductivity respectively, establish the corresponding relationship between CO2 volume fraction and each monitoring parameter index, and determine the warning values and safety limits of each monitoring parameter index according to the allowable range of CO2 content in the soil.

Images