Leakage monitoring, gas injection and storage system and method for geological storage of carbon dioxide

Abstract

The invention discloses a leakage monitoring, gas injection and sequestration system and method for geological sequestration of carbon dioxide, and relates to the technical field of geological sequestration of carbon dioxide, and the system comprises a multi-stage gas injection device which is composed of a gas injection pipeline network with distributed gas injection holes and is used for injecting carbon dioxide gas into different depths of a geological sequestration area; the intelligent monitoring system comprises a pressure sensor, a temperature sensor and a concentration sensor which are arranged at different depths of the geological sequestration area; the sealing layer structure is made of a high-strength low-permeability material and is used for sealing the boundary of the geological storage area; and the central controller is connected with the intelligent monitoring system and used for executing gas injection control, leakage analysis and early warning decision, and efficient, safe and long-term storage of carbon dioxide in the deep unmining coal seam can be achieved.

Description

Technical Field

[0001] The present application relates to the technical field of carbon dioxide geological sequestration, and particularly relates to a leakage monitoring, gas injection and sequestration system and method for carbon dioxide geological sequestration. Background Art

[0002] Due to their large burial depth, complex geological conditions and high mining difficulty, deep unminable coal seams are difficult to mine by conventional means. However, due to their large storage space, they have become potential carbon dioxide sequestration sites.

[0003] At present, the geological environment of deep unminable coal seams has characteristics such as high temperature, high pressure and high permeability. Under high temperature conditions, the physical and chemical properties of carbon dioxide will change, increasing the complexity of its migration and sequestration in coal seams; the high-pressure conditions pose extremely high requirements on the compressive performance of sequestration equipment, and traditional equipment is difficult to operate stably for a long time; the high permeability makes carbon dioxide easy to escape, making it difficult to ensure long-term sequestration effects. Summary of the Invention

[0004] The purpose of the present application is to provide a leakage monitoring, gas injection and sequestration system and method for carbon dioxide geological sequestration, which can achieve efficient, safe and long-term sequestration of carbon dioxide in deep unminable coal seams.

[0005] To achieve the above purpose, the present application provides the following solutions: In a first aspect, the present application provides a leakage monitoring, gas injection and sequestration system for carbon dioxide geological sequestration, including: A multi-stage gas injection device, which consists of a gas injection pipeline network with distributed gas injection holes, and is used to inject carbon dioxide gas into different depths of the geological sequestration area.

[0006] An intelligent monitoring system, including pressure sensors, temperature sensors and concentration sensors arranged at different depths of the geological sequestration area.

[0007] A sealing layer structure, which is composed of high-strength and low-permeability materials and is used to seal the boundary of the geological sequestration area.

[0008] A central controller, which is connected to the intelligent monitoring system and is used to execute gas injection control, leakage analysis and warning mechanisms.

[0009] Optionally, the multi-stage gas injection device includes at least two stages of gas injection pipelines; the diameter d of the gas injection holes of each stage of gas injection pipeline is in the range of [2, 10] mm, and the spacing l is in the range of [20, 50] cm; when the permeability k > 10 mD, d = 2 mm and l = 50 cm are taken; when k < 1 mD, d = 10 mm and l = 20 cm are taken; the pressure-bearing capacity of the gas injection pipeline is ≥ 50 MPa; the gas injection pipeline is connected to the adjacent gas injection pipeline by welding or flange connection.

[0010] Optionally, the gas injection hole adopts a conical diffusion structure; the inlet diameter d1 and the outlet diameter d2 of the gas injection hole satisfy d2 / d1 ∈ [1.5 - 2.0]; the pore wall of the gas injection hole is coated with a nano-hydrophobic coating.

[0011] Optionally, the intelligent monitoring system consists of a distributed sensor array and a topology structure.

[0012] The distributed sensor array consists of several pressure sensors, temperature sensors, and CO2 concentration sensors.

[0013] The topology structure is arranged according to the strike of the coal seam; the interval between pressure sensors in the topology structure is 10 meters, the interval between temperature sensors is 15 meters, and the interval between CO2 concentration sensors is 5 meters.

[0014] Optionally, the central controller is used to predict the CO2 migration path based on the LSTM-random forest hybrid model; the input of the central controller is the monitoring data collected by the intelligent monitoring system; the monitoring data includes the real-time pressure P, temperature T, concentration C, and historical geological data.

[0015] Optionally, the online update mechanism of the LSTM-random forest hybrid model is as follows: When the monitoring data collected by the intelligent monitoring system deviates from the predicted value by more than the set threshold, incremental learning is triggered; the incremental learning is to retain the original model weights and add hidden layer neurons to process abnormal patterns.

[0016] In a second aspect, the present application provides a method for leakage monitoring, gas injection, and storage of carbon dioxide geological storage, including: Using three-dimensional seismic exploration to obtain coal seam parameters and obtain a gas injection hole distribution model.

[0017] According to the gas injection hole distribution model, based on a multi-stage gas injection device, inject carbon dioxide into the geological storage area at the first-stage pressure.

[0018] Obtain the real-time pressure P of the geological storage area. When the pressure in the geological storage area reaches the critical value, inject carbon dioxide into the geological storage area at the second-stage pressure; the first-stage pressure is less than the second-stage pressure.

[0019] When the carbon dioxide injection is completed, lay a composite sealing layer in the geological storage area to form a sealing layer structure.

[0020] Through the intelligent monitoring system, obtain the real-time pressure P, temperature T, and concentration C of the geological storage area in real time.

[0021] When the monitoring data is abnormal, a warning signal is issued, and leakage analysis is performed based on the central controller to predict the CO2 migration path.

[0022] Optionally, the upper layer of the composite sealing layer is nano-modified cement, and the lower layer is a polymer gel.

[0023] Optionally, when the carbon dioxide injection is completed, a composite sealing layer is laid in the geological storage area to form a sealing layer structure, specifically including: Add carbon nanotube reinforcing agents to the nano-modified cement to generate a nano-modified cement layer with high strength and improved impermeability.

[0024] The polymer gel is evenly coated under the nano-modified cement layer to form a double-layer composite sealing structure; the polymer gel uses pH-responsive polyacrylamide.

[0025] Optionally, after the warning signal is issued, it further includes: Determine the warning mechanism; the warning mechanism includes a primary warning and a secondary warning; the primary warning is to start the injection of the plugging agent; the secondary warning is to start the suction recovery.

[0026] According to the specific embodiments provided by the present application, the following technical effects are disclosed in the present application: The present application provides a leakage monitoring, gas injection and storage system and method for carbon dioxide geological storage. In the system, the multi-stage gas injection device injects carbon dioxide gas evenly and precisely into different depths of the geological storage area through a gas injection pipeline network with distributed injection holes, ensuring the wide distribution of carbon dioxide gas in the geological storage area and improving the storage efficiency. The intelligent monitoring system real-time monitors the environmental parameters and carbon dioxide concentration in the geological storage area through pressure sensors, temperature sensors and concentration sensors arranged at different depths of the geological storage area, providing accurate data support for the central controller. This helps to detect abnormal situations in a timely manner, thus ensuring the safety of the storage process. The sealing layer structure is composed of high-strength and low-permeability materials, effectively sealing the boundary of the geological storage area and preventing the leakage of carbon dioxide gas. This sealing layer structure not only has excellent sealing performance, but also has good durability and stability, and can maintain the closed state of the geological storage area for a long time. Finally, as the core of the entire system, the central controller is closely connected to the intelligent monitoring system, can receive and process monitoring data in real time, and execute gas injection control, leakage analysis and warning mechanism according to the data results. The central controller has a high degree of intelligence and automation, and can achieve precise control and timely adjustment of the geological storage process, thus ensuring the efficient, safe and long-term storage of carbon dioxide in deep unmineable coal seams. Description of the Drawings

[0027] To more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0028] Figure 1 Schematic diagram of a leakage monitoring, gas injection and storage system for carbon dioxide geological storage provided by an embodiment of the present application.

[0029] Figure 2 Schematic flow diagram of a method for leakage monitoring, gas injection and storage of carbon dioxide geological storage provided by an embodiment of the present application. Detailed implementation manners

[0030] The following will clearly and completely describe the technical solutions in the embodiments of the present application with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all of them. Based on the embodiments of the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present application.

[0031] Most of the prior arts focus on the collaborative operation of coalbed methane extraction and carbon dioxide storage, and there is less research on carbon dioxide storage technologies that do not involve coalbed methane extraction. This results in a lack of effective technical means when simply carrying out carbon dioxide storage in deep unminable coal seams, unable to meet the actual needs.

[0032] 1. Difficulty in the accuracy of leakage monitoring: When the current technology monitors the leakage of carbon dioxide storage in deep unminable coal seams, it is unable to accurately determine the leakage location and leakage volume. The high-temperature, high-pressure, and high-permeability environment of the coal seam interferes with the performance of sensors, resulting in large deviations in monitoring data, making it difficult to accurately judge the leakage point and leakage scale, and unable to take effective measures to control leakage in a timely manner.

[0033] 2. Timeliness dilemma of real-time monitoring: Existing monitoring means are difficult to achieve real-time tracking of carbon dioxide leakage. Data transmission delay and low processing efficiency make the monitoring information lag behind the actual leakage situation, unable to detect early leakage signs in a timely manner, missing the best disposal opportunity, which may lead to the expansion of the leakage range and the aggravation of hazards.

[0034] 3. Lack of integrity of the monitoring system: There is a lack of a comprehensive and integrated monitoring system that cannot simultaneously consider the influence of geological conditions, environmental factors, and the state of the storage system itself on carbon dioxide leakage. Only focusing on single factors or partial indicators, it is impossible to accurately evaluate the leakage risk and difficult to build a complete leakage monitoring and warning mechanism.

[0035] The objective of this application is to provide a leakage monitoring, gas injection and storage system and method for geological carbon dioxide storage, which can achieve efficient, safe and long-term storage of carbon dioxide in deep unminable coal seams.

[0036] To make the above objectives, features and advantages of this application more obvious and understandable, the following further detailed description of this application is provided in conjunction with the accompanying drawings and specific embodiments.

[0037] Embodiment 1 As Figure 1 shown, this embodiment provides a leakage monitoring, gas injection and storage system for geological carbon dioxide storage, including: A multi-stage gas injection device, which consists of a gas injection pipeline network with distributed gas injection holes and is used to inject carbon dioxide gas into different depths of the geological storage area.

[0038] An intelligent monitoring system, including pressure sensors, temperature sensors and concentration sensors arranged at different depths of the geological storage area.

[0039] A sealing layer structure, which is composed of high-strength and low-permeability materials and is used to seal the boundary of the geological storage area.

[0040] A central controller, which is connected to the intelligent monitoring system and is used to execute gas injection control, leakage analysis and warning mechanisms.

[0041] Among them, the multi-stage gas injection device includes at least two stages of gas injection pipelines; the diameter d of the gas injection holes of each stage of gas injection pipeline belongs to [2, 10] mm, and the spacing l belongs to [20, 50] cm; when the permeability k > 10 mD, d = 2 mm and l = 50 cm are taken; when k < 1 mD, d = 10 mm and l = 20 cm are taken; the pressure-bearing capacity of the gas injection pipeline is ≥ 50 MPa; the gas injection pipeline is connected to the adjacent gas injection pipeline by welding or flange connection.

[0042] Specifically, the multi-stage gas injection device is composed of several gas injection pipelines, and a plurality of gas injection holes are evenly arranged on each pipeline. The diameter range of the gas injection holes is set between 2 mm and 10 mm, and the hole spacing is between 20 cm and 50 cm. These specific values are accurately optimized according to key geological conditions such as the permeability and porosity of the coal seam. For example, in a coal seam with a higher permeability, the diameter of the gas injection holes can be appropriately reduced to 2 mm and the hole spacing increased to 50 cm to control the injection rate and distribution range of carbon dioxide; on the contrary, in a coal seam with a lower permeability, the diameter of the gas injection holes needs to be increased to 10 mm and the hole spacing reduced to 20 cm to ensure that carbon dioxide can fully penetrate deep into the coal seam.

[0043] The multi-stage gas injection device adopts a staged injection method. First, carbon dioxide is injected into the coal seam through the first-stage gas injection pipeline at a relatively low pressure. When the coal seam pressure reaches a certain threshold, the second-stage gas injection pipeline is opened, and the injection pressure is gradually increased, but always kept within the safe pressure-bearing range of the equipment. This staged injection method can gradually increase the coal seam pressure, make carbon dioxide diffuse evenly in the coal seam, reduce its escape during the injection process, and at the same time reduce the pressure requirement on a single device, improving the safety and stability of equipment operation.

[0044] Among them, the gas injection holes adopt a conical diffusion structure; the inlet diameter d1 and the outlet diameter d2 of the gas injection holes satisfy d2 / d1 ∈ [1.5 - 2.0]; the pore walls of the gas injection holes are coated with a nano-hydrophobic coating.

[0045] Among them, the intelligent monitoring system is composed of a distributed sensor array and a topology structure.

[0046] The distributed sensor array consists of several pressure sensors, temperature sensors, and CO2 concentration sensors.

[0047] The topology structure is arranged according to the trend of the coal seam; the interval between pressure sensors in the topology structure is 10 meters, the interval between temperature sensors is 15 meters, and the interval between CO2 concentration sensors is 5 meters.

[0048] At different positions in the geological storage area, including inside the coal seam, the sealing top layer, and the sealing bottom layer, pressure sensors, temperature sensors, and gas concentration sensors are evenly arranged. The accuracy of the pressure sensors reaches ±0.1 kPa, which can monitor the change of coal seam pressure in real time; the measurement range of the temperature sensors is 0°C - 100°C, and the accuracy is ±0.5°C, accurately obtaining the coal seam temperature information; the gas concentration sensors can detect the carbon dioxide concentration range of 0 ppm - 5000 ppm, and the accuracy is ±5 ppm, realizing the precise monitoring of the carbon dioxide concentration.

[0049] Among them, the central controller is used to predict the CO2 migration path based on the LSTM-random forest hybrid model; the input of the central controller is the monitoring data collected by the intelligent monitoring system; the monitoring data includes the real-time pressure P, temperature T, concentration C, and historical geological data. The online update mechanism of the LSTM-random forest hybrid model is: when the monitoring data collected by the intelligent monitoring system deviates from the predicted value by more than the set threshold, incremental learning is triggered; the incremental learning is to retain the original model weights and add hidden layer neurons to process abnormal patterns.

[0050] Specifically, intelligent algorithms are used to perform real-time analysis on the data collected by sensors. The algorithms are based on big data and machine learning technologies. First, they learn and train on historical geological data to establish a mathematical model between geological parameters and the migration and storage stability of carbon dioxide. Then, based on the real-time monitoring data, the migration path and storage stability of carbon dioxide are predicted through the model. For example, when it is detected that the pressure suddenly increases and the carbon dioxide concentration changes abnormally in a certain area of the coal seam, the algorithm can quickly determine the possible risk area of carbon dioxide escape and predict its diffusion direction, providing a basis for taking corresponding measures.

[0051] Embodiment 2 As Figure 2 shown, this embodiment provides a method for leakage monitoring, gas injection and storage of geological carbon dioxide sequestration, including: Using three-dimensional seismic exploration to obtain coal seam parameters and obtain a gas injection hole distribution model.

[0052] According to the gas injection hole distribution model, based on a multi-stage gas injection device, carbon dioxide is injected into the geological storage area at the first-stage pressure.

[0053] Obtain the real-time pressure P of the geological storage area. When the pressure of the geological storage area reaches the critical value, inject carbon dioxide into the geological storage area at the second-stage pressure; the first-stage pressure is less than the second-stage pressure.

[0054] When the carbon dioxide injection is completed, lay a composite sealing layer in the geological storage area to form a sealing layer structure.

[0055] Through an intelligent monitoring system, obtain the real-time pressure P, temperature T, and concentration C of the geological storage area in real time.

[0056] When the monitoring data is abnormal, send out a warning signal and perform leakage analysis based on the central controller to predict the CO2 migration path.

[0057] Specifically, in this embodiment, 3D seismic exploration technology is used to conduct a detailed exploration of the storage area to obtain accurate geological data of the coal seam. According to the exploration results, a professional geological modeling software is used to design the layout and parameters of the gas injection pipeline. For example, the total length of the gas injection pipeline is determined to be 1500 m, the number and distribution of branch pipelines, as well as the specific positions and parameters of the gas injection holes. Gas injection stage: First, the first-stage gas injection pipeline is opened, and carbon dioxide is injected at a pressure of 10 MPa, and the injection rate is controlled at 50 m³ / h. When the coal seam pressure reaches 15 MPa, the second-stage gas injection pipeline is opened, and the injection pressure is gradually increased to 25 MPa, while the injection rate is adjusted to 100 m³ / h. During the gas injection process, closely monitor the changes in coal seam pressure and carbon dioxide concentration to ensure the safety and stability of the gas injection process. Sealing stage: Special cement sealing layers with a thickness of 1 m are laid on the top and bottom of the coal seam. During the laying process, strictly control the flatness and density of the sealing layer to ensure the sealing effect. After the sealing layer is laid, a sealing performance test is carried out, and only after passing the test can the next stage be entered. Monitoring stage: The intelligent monitoring system continuously collects geological parameters and carbon dioxide concentration data in the storage area. When the carbon dioxide concentration in a certain area is monitored to exceed the set threshold of 1000 ppm, the system immediately issues a warning signal. Technical personnel analyze the reasons and take corresponding measures according to the warning information, such as adjusting the gas injection strategy and strengthening the inspection of the sealing layer, to ensure the carbon dioxide storage effect.

[0058] Wherein, the upper layer of the composite sealing layer is nano-modified cement, and the lower layer is a polymer gel.

[0059] In some embodiments, when the carbon dioxide injection is completed, a composite sealing layer is laid in the geological storage area to form a sealing layer structure, specifically including: Add carbon nanotube reinforcing agents to the nano-modified cement to generate a nano-modified cement layer with high strength and improved impermeability.

[0060] The polymer gel is evenly coated under the nano-modified cement layer to form a double-layer composite sealing structure; the polymer gel uses pH-responsive polyacrylamide.

[0061] In some embodiments, after the warning signal is issued, it further includes: Determine the warning mechanism; the warning mechanism includes a primary warning and a secondary warning; the primary warning is to start the injection of the plugging agent; the secondary warning is to start the suction and recovery.

[0062] In summary, the present application has the following technical effects: 1. Precise location of leakage position and quantification of leakage volume: By reasonably arranging high-precision pressure sensors, temperature sensors and gas concentration sensors inside the coal seam, the capping layer and the bottom sealing layer, and combining in-depth analysis of monitoring data with intelligent algorithms, the leakage position of carbon dioxide can be quickly and accurately located, and the leakage volume can be accurately calculated. This provides a key basis for carrying out targeted plugging and leakage control work, and greatly improves the timeliness and effectiveness of leakage treatment.

[0063] 2. Realize real-time dynamic monitoring of leakage: Construct an efficient data acquisition, transmission and processing system, adopt advanced wireless transmission technology and high-speed data processing algorithms, significantly shorten the data transmission and processing time, and realize real-time dynamic monitoring of carbon dioxide leakage. It can capture leakage signals in the first time, issue early warnings in a timely manner, strive for precious time to take emergency measures, and effectively contain the development of leakage accidents.

[0064] 3. Build an all-round comprehensive monitoring system: Comprehensively consider various factors such as geological structure, coal seam characteristics, environmental temperature and humidity, and operation parameters of the storage system, and establish a perfect carbon dioxide leakage monitoring system. Through the fusion analysis of multi-source data, accurately evaluate the leakage risk level, predict the leakage trend in advance, and formulate scientific and reasonable prevention and response strategies to ensure the safety and stability of carbon dioxide geological storage.

[0065] The technical features of the above embodiments can be combined arbitrarily. For the sake of concise description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope recorded in this specification.

[0066] In this article, specific examples are used to elaborate on the principles and implementation methods of this application. The descriptions of the above embodiments are only used to help understand the method and its core idea of this application; at the same time, for those of ordinary skill in the art, according to the idea of this application, there will be changes in the specific implementation methods and application scopes. To sum up, the content of this specification should not be construed as a limitation to this application.

Claims

1. A leakage monitoring, gas injection and storage system for geological storage of carbon dioxide, characterized in that Comprising: A multi-stage gas injection device, consisting of a gas injection pipeline network with distributed gas injection holes, for injecting carbon dioxide gas into different depths of the geological storage area; An intelligent monitoring system, including pressure sensors, temperature sensors and concentration sensors arranged at different depths of the geological storage area; A sealing layer structure, composed of high-strength and low-permeability materials, for sealing the boundary of the geological storage area; A central controller, connected to the intelligent monitoring system, for executing gas injection control, leakage analysis and warning mechanisms.

2. The leakage monitoring, gas injection and storage system for geological storage of carbon dioxide according to claim 1, characterized in that, The multi-stage gas injection device includes at least two stages of gas injection pipelines; the diameter d of the gas injection holes of each stage of gas injection pipeline ∈ [2, 10] mm, and the spacing l ∈ [20, 50] cm; when the permeability k > 10 mD, d = 2 mm and l = 50 cm are taken; when k < 1 mD, d = 10 mm and l = 20 cm are taken; the pressure-bearing capacity of the gas injection pipeline ≥ 50 MPa; the gas injection pipelines are connected to adjacent gas injection pipelines by welding or flange connection.

3. A leakage monitoring, gas injection and storage system for geological storage of carbon dioxide according to claim 1, characterized in that, The gas injection holes adopt a conical diffusion structure; the inlet diameter d1 and the outlet diameter d2 of the gas injection holes satisfy d2 / d1 ∈ [1.5 - 2.0]; the pore walls of the gas injection holes are coated with a nano-hydrophobic coating.

4. A leakage monitoring, gas injection and storage system for geological sequestration of carbon dioxide according to claim 1, characterized in that, The intelligent monitoring system is composed of a distributed sensor array and a topology structure; The distributed sensor array consists of a number of pressure sensors, temperature sensors and CO2 concentration sensors; The topology structure is arranged according to the strike of the coal seam; the interval of the pressure sensors in the topology structure is 10 meters, the interval of the temperature sensors is 15 meters, and the interval of the CO2 concentration sensors is 5 meters.

5. A leakage monitoring, gas injection and storage system for geological sequestration of carbon dioxide according to claim 1, characterized in that, The central controller is used to predict the CO2 migration path based on the LSTM-random forest hybrid model; the input of the central controller is the monitoring data collected by the intelligent monitoring system; the monitoring data includes the real-time pressure P, temperature T, concentration C and historical geological data.

6. The leakage monitoring, gas injection and storage system for geological storage of carbon dioxide according to claim 5, characterized in that, The online update mechanism of the LSTM-random forest hybrid model is: When the monitoring data collected by the intelligent monitoring system deviates from the predicted value by more than the set threshold, incremental learning is triggered; the incremental learning is to retain the original model weights and add hidden layer neurons to process abnormal patterns.

7. A method for leakage monitoring, gas injection and storage in geological carbon dioxide sequestration, characterized in that, Comprising: Using three-dimensional seismic exploration to obtain coal seam parameters and obtain a gas injection hole distribution model; According to the gas injection hole distribution model, based on the multi-stage gas injection device, injecting carbon dioxide into the geological storage area at the first-stage pressure; Obtaining the real-time pressure P of the geological storage area, and when the pressure of the geological storage area reaches the critical value, injecting carbon dioxide into the geological storage area at the second-stage pressure; the first-stage pressure is less than the second-stage pressure; When the carbon dioxide injection is completed, laying a composite sealing layer in the geological storage area to form a sealing layer structure; Through the intelligent monitoring system, obtaining the real-time pressure P, temperature T, and concentration C of the geological storage area in real time; When the monitoring data is abnormal, sending out a warning signal and performing leakage analysis based on the central controller to predict the CO2 migration path.

8. A leakage monitoring, gas injection and storage method for geological storage of carbon dioxide according to claim 7, characterized in that, The upper layer of the composite sealing layer is nano-modified cement, and the lower layer is a polymer gel.

9. A leakage monitoring, gas injection and storage method for geological storage of carbon dioxide according to claim 8, characterized in that, When the carbon dioxide injection is completed, laying a composite sealing layer in the geological storage area to form a sealing layer structure, specifically including: Adding a carbon nanotube reinforcing agent to the nano-modified cement to form a nano-modified cement layer with high strength and improved impermeability; Evenly coating a polymer gel under the nano-modified cement layer to form a double-layer composite sealing structure; the polymer gel uses pH-responsive polyacrylamide.

10. A leakage monitoring, gas injection and storage method for geological storage of carbon dioxide according to claim 8, characterized in that, After sending out a warning signal, it further includes: Determining an early warning mechanism; the early warning mechanism includes a first-level early warning and a second-level early warning; the first-level early warning is to start injecting a plugging agent; the second-level early warning is to start suction recovery.

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