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

Abstract

The present application discloses a leakage monitoring, gas injection and storage system and method for carbon dioxide geological storage, which relates to the technical field of carbon dioxide geological storage. The system includes a multi-stage gas injection device, which is composed 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; 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, which is composed of high-strength low-permeability materials, and is used to seal the boundary of the geological storage area; a central controller, which is connected to the intelligent monitoring system and is used to execute gas injection control, leakage analysis and early warning decision-making. The present application can realize the efficient, safe and long-term storage of carbon dioxide in deep unmineable coal seams.

Description

Technical Field

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

[0002] Deep unmineable coal seams are difficult to mine using conventional means due to their great burial depth, complex geological conditions, and high mining difficulty. However, they have a large storage space and thus become a highly potential site for carbon dioxide storage.

[0003] Currently, the geological environment of deep, unmineable coal seams is characterized by high temperature, high pressure, and high permeability. High temperatures alter the physical and chemical properties of carbon dioxide, increasing the complexity of its migration and storage within coal seams. High pressures place extremely high demands on the compressive strength of storage equipment, making it difficult for traditional equipment to maintain long-term stable operation. High permeability also makes it easy for carbon dioxide to escape, making it difficult to ensure long-term storage. Summary of the Invention

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

[0005] To achieve the above objectives, this application provides the following solutions:

[0006] In a first aspect, the present application provides a leakage monitoring, gas injection and storage system for geological storage of carbon dioxide, comprising:

[0007] The multi-stage gas injection device consists of a gas injection pipeline network with distributed gas injection holes, which is used to inject carbon dioxide gas into different depths of the geological storage area.

[0008] The intelligent monitoring system includes pressure sensors, temperature sensors and concentration sensors arranged at different depths in the geological storage area.

[0009] The sealing layer structure is made of high-strength and low-permeability materials and is used to seal the boundaries of the geological storage area.

[0010] The central controller is connected to the intelligent monitoring system to perform gas injection control, leakage analysis and early warning mechanisms.

[0011] Optionally, the multi-stage gas injection device includes at least two stages of gas injection pipelines; the diameter of the gas injection holes of each stage of the gas injection pipeline is d∈[2,10]mm, and the spacing is l∈[20,50]cm; when the permeability k>10mD, d=2mm and l=50cm are taken; when k<1mD, d=10mm and l=20cm are taken; the pressure bearing capacity of the gas injection pipeline is ≥50MPa; the gas injection pipeline is connected to the adjacent gas injection pipeline by welding or flange connection.

[0012] 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]; and the hole wall of the gas injection hole is coated with a nano-hydrophobic coating.

[0013] Optionally, the intelligent monitoring system is composed of a distributed sensor array and a topological structure.

[0014] The distributed sensor array consists of several pressure sensors, temperature sensors and CO2 concentration sensors.

[0015] The topological structure is arranged according to the direction of the coal seam; in the topological structure, the interval between pressure sensors is 10 meters, the interval between temperature sensors is 15 meters, and the interval between CO2 concentration sensors is 5 meters.

[0016] 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 real-time pressure P, temperature T, concentration C and historical geological data.

[0017] Optionally, the online update mechanism of the LSTM-random forest hybrid model is:

[0018] When the monitoring data collected by the intelligent monitoring system deviates from the predicted value by more than a 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.

[0019] In a second aspect, the present application provides a method for leakage monitoring, gas injection and storage of carbon dioxide geological storage, comprising:

[0020] Three-dimensional seismic exploration is used to obtain coal seam parameters and obtain the gas injection pore distribution model.

[0021] According to the gas injection hole distribution model, based on a multi-stage gas injection device, the first stage pressure is used to inject carbon dioxide into the geological storage area.

[0022] The real-time pressure P of the geological storage area is obtained. When the pressure of the geological storage area reaches a critical value, the second-level pressure is used to inject carbon dioxide into the geological storage area; the first-level pressure is lower than the second-level pressure.

[0023] When the carbon dioxide injection is completed, a composite sealing layer is laid in the geological storage area to form a sealing layer structure.

[0024] Through the intelligent monitoring system, the real-time pressure P, temperature T and concentration C of the geological storage area can be obtained in real time.

[0025] When the monitoring data is abnormal, an early warning signal is issued, and leakage analysis is performed based on the central controller to predict the CO2 migration path.

[0026] Optionally, the upper layer of the composite sealing layer is nano-modified cement, and the lower layer is polymer gel.

[0027] Optionally, when the CO2 injection is completed, a composite sealing layer is laid in the geological storage area to form a sealing layer structure, specifically including:

[0028] Adding carbon nanotube reinforcement to nano-modified cement produces a nano-modified cement layer with high strength and improved anti-permeability.

[0029] The polymer gel is evenly coated below the nano-modified cement layer to form a double-layer composite sealing structure; the polymer gel adopts pH-responsive polyacrylamide.

[0030] Optionally, after issuing the warning signal, the method further includes:

[0031] Determine 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 the injection of the plugging agent; the second-level early warning is to start the suction recovery.

[0032] According to the specific embodiments provided in this application, this application discloses the following technical effects:

[0033] This application provides a leakage monitoring, gas injection, and storage system and method for carbon dioxide geological storage. In this system, a multi-stage gas injection device uses a gas injection pipeline network with distributed gas injection holes to uniformly and accurately inject carbon dioxide gas into the geological storage area at different depths, ensuring widespread distribution of carbon dioxide gas within the geological storage area and improving storage efficiency. The intelligent monitoring system uses pressure sensors, temperature sensors, and concentration sensors arranged at different depths in the geological storage area to monitor environmental parameters and carbon dioxide concentrations within the geological storage area in real time, providing accurate data support to the central controller. This helps to promptly detect abnormal conditions, thereby ensuring the safety of the storage process. The sealing layer structure is composed of high-strength, low-permeability materials, effectively sealing the boundaries of the geological storage area and preventing carbon dioxide gas leakage. This sealing layer structure not only has excellent sealing performance but also has good durability and stability, capable of maintaining the geological storage area in a sealed state for a long time. Finally, the central controller, as the core of the entire system, is closely connected to the intelligent monitoring system, capable of receiving and processing monitoring data in real time, and implementing gas injection control, leakage analysis, and early warning mechanisms based on the data results. The central controller has a high degree of intelligence and automation, which enables precise control and timely adjustment of the geological storage process, thereby ensuring the efficient, safe and long-term storage of carbon dioxide in deep, unmineable coal seams. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0035] Figure 1 A schematic diagram of a leakage monitoring, gas injection and storage system for carbon dioxide geological storage provided in one embodiment of the present application.

[0036] Figure 2 A schematic flow chart of a method for leakage monitoring, gas injection and storage of carbon dioxide geological storage provided in one embodiment of the present application. DETAILED DESCRIPTION

[0037] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0038] Existing technologies primarily focus on the coordinated operation of coalbed methane extraction and CO2 storage, with relatively little research on CO2 storage technologies that don't involve coalbed methane extraction. This results in a lack of effective technical means for simply storing CO2 in deep, unminable coal seams, making it impossible to meet actual needs.

[0039] 1. Accurate leak monitoring: Current technologies cannot accurately determine the location and volume of leaks in deep, unmineable coal seams. The high temperature, high pressure, and high permeability of the coal seams interfere with sensor performance, resulting in significant deviations in monitoring data. This makes it difficult to accurately determine the leak point and scale, hindering the timely implementation of effective measures to control the leak.

[0040] 2. The timeliness of real-time monitoring: Existing monitoring methods struggle to track CO2 leaks in real time. Data transmission delays and low processing efficiency cause monitoring information to lag behind the actual leak situation, making it impossible to detect early signs of a leak. This can lead to missed opportunities for action and potentially expand the scope of the leak and exacerbate the damage.

[0041] 3. Lack of integrity in the monitoring system: The lack of a comprehensive monitoring system fails to account for the impacts of geological conditions, environmental factors, and the storage system's inherent state on CO2 leakage. Focusing solely on a single factor or a subset of indicators makes it impossible to accurately assess leakage risks and establish a comprehensive leakage monitoring and early warning mechanism.

[0042] The purpose of this application is to provide a leakage monitoring, gas injection and storage system and method for carbon dioxide geological storage, which can achieve efficient, safe and long-term storage of carbon dioxide in deep unmineable coal seams.

[0043] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0044] Example 1

[0045] like Figure 1 As shown, this embodiment provides a leakage monitoring, gas injection and storage system for geological storage of carbon dioxide, including:

[0046] The multi-stage gas injection device consists of a gas injection pipeline network with distributed gas injection holes, which is used to inject carbon dioxide gas into different depths of the geological storage area.

[0047] The intelligent monitoring system includes pressure sensors, temperature sensors and concentration sensors arranged at different depths in the geological storage area.

[0048] The sealing layer structure is made of high-strength and low-permeability materials and is used to seal the boundaries of the geological storage area.

[0049] The central controller is connected to the intelligent monitoring system to perform gas injection control, leakage analysis and early warning mechanisms.

[0050] In which, the multi-stage gas injection device includes at least two levels of gas injection pipelines; the diameter of the gas injection holes of each level of the gas injection pipeline is d∈[2,10]mm, and the spacing is l∈[20,50]cm; when the permeability k>10mD, d=2mm and l=50cm are taken; when k<1mD, d=10mm and l=20cm are taken; the pressure bearing capacity of the gas injection pipeline is ≥50MPa; the gas injection pipeline is connected to the adjacent gas injection pipeline by welding or flange connection.

[0051] Specifically, the multi-stage gas injection device consists of several gas injection pipes, each of which is evenly distributed with multiple gas injection holes. 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 obtained through precise optimization based on key geological conditions such as the permeability and porosity of the coal seam. For example, in coal seams with 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; conversely, in coal seams with 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.

[0052] The multi-stage gas injection device uses a staged injection method, initially injecting carbon dioxide into the coal seam at a low pressure through the first-stage gas injection pipeline. When the coal seam pressure reaches a certain threshold, the second-stage gas injection pipeline is opened, gradually increasing the injection pressure while always maintaining it within the equipment's safe pressure range. This staged injection method gradually increases the coal seam pressure, allowing carbon dioxide to diffuse evenly throughout the coal seam and reducing its escape during the injection process. It also reduces the pressure requirement for a single device, improving the safety and stability of its operation.

[0053] 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]; and the hole wall of the gas injection hole is coated with a nano-hydrophobic coating.

[0054] Wherein, the intelligent monitoring system is composed of a distributed sensor array and a topological structure.

[0055] The distributed sensor array consists of several pressure sensors, temperature sensors and CO2 concentration sensors.

[0056] The topological structure is arranged according to the direction of the coal seam; in the topological structure, the interval between pressure sensors is 10 meters, the interval between temperature sensors is 15 meters, and the interval between CO2 concentration sensors is 5 meters.

[0057] Pressure sensors, temperature sensors, and gas concentration sensors are evenly distributed throughout the geological storage area, including within the coal seam, on the top and bottom seals. The pressure sensors, with an accuracy of ±0.1 kPa, enable real-time monitoring of coal seam pressure changes. The temperature sensors, with a measurement range of 0°C to 100°C and an accuracy of ±0.5°C, accurately capture coal seam temperature information. The gas concentration sensors can detect carbon dioxide concentrations from 0 ppm to 5000 ppm with an accuracy of ±5 ppm, enabling precise monitoring of carbon dioxide concentrations.

[0058] The central controller is used to predict CO2 migration paths based on a hybrid LSTM-random forest model. The central controller's input is monitoring data collected by the intelligent monitoring system, including real-time pressure P, temperature T, concentration C, and historical geological data. The LSTM-random forest hybrid model's online update mechanism triggers incremental learning when the monitoring data collected by the intelligent monitoring system deviates from the predicted value by more than a set threshold. This incremental learning retains the original model weights and adds hidden layer neurons to handle abnormal patterns.

[0059] Specifically, intelligent algorithms are used to analyze sensor data in real time. Based on big data and machine learning techniques, the algorithms first learn and train historical geological data to establish a mathematical model linking geological parameters with CO2 migration and storage stability. Then, based on real-time monitoring data, the model predicts CO2 migration paths and storage stability. For example, if a sudden increase in pressure and abnormal changes in CO2 concentration are detected in a certain area of ​​a coal seam, the algorithm can quickly identify areas at risk of CO2 escape and predict its diffusion direction, providing a basis for taking appropriate measures.

[0060] Example 2

[0061] like Figure 2 As shown, this embodiment provides a method for leakage monitoring, gas injection and storage of carbon dioxide geological storage, including:

[0062] Three-dimensional seismic exploration is used to obtain coal seam parameters and obtain the gas injection pore distribution model.

[0063] According to the gas injection hole distribution model, based on a multi-stage gas injection device, the first stage pressure is used to inject carbon dioxide into the geological storage area.

[0064] The real-time pressure P of the geological storage area is obtained. When the pressure of the geological storage area reaches a critical value, the second-level pressure is used to inject carbon dioxide into the geological storage area; the first-level pressure is lower than the second-level pressure.

[0065] When the carbon dioxide injection is completed, a composite sealing layer is laid in the geological storage area to form a sealing layer structure.

[0066] Through the intelligent monitoring system, the real-time pressure P, temperature T and concentration C of the geological storage area can be obtained in real time.

[0067] When the monitoring data is abnormal, an early warning signal is issued, and leakage analysis is performed based on the central controller to predict the CO2 migration path.

[0068] Specifically, in this embodiment, 3D seismic exploration technology was used to conduct a detailed survey of the storage area to obtain precise geological data on the coal seams. Based on the survey results, the layout and parameters of the gas injection pipeline were designed using professional geological modeling software. For example, the total length of the gas injection pipeline was determined to be 1500 meters, the number and distribution of branch pipelines, and the specific locations and parameters of the gas injection holes were determined. During the gas injection phase, the first-stage gas injection pipeline was opened and carbon dioxide was injected at a pressure of 10 MPa, with an injection rate of 50 m³ / h. Once the coal seam pressure reached 15 MPa, the second-stage gas injection pipeline was opened and the injection pressure was gradually increased to 25 MPa, while the injection rate was adjusted to 100 m³ / h. During the gas injection process, changes in coal seam pressure and carbon dioxide concentration were closely monitored to ensure a safe and stable injection process. During the sealing phase, a 1-meter-thick special cement sealing layer was laid on the top and bottom of the coal seam. During the laying process, the flatness and density of the sealing layer were strictly controlled to ensure a sealing effect. After the sealing layer was laid, a sealing test was conducted, and only those who passed the test could proceed to the next phase. Monitoring Phase: The intelligent monitoring system collects real-time data on geological parameters and CO2 concentrations within the storage area. If the CO2 concentration in a particular area exceeds the set threshold of 1000 ppm, the system immediately issues an early warning. Based on this warning, technicians analyze the cause and implement appropriate measures, such as adjusting the gas injection strategy and strengthening seal inspections, to ensure CO2 storage effectiveness.

[0069] The upper layer of the composite sealing layer is nano-modified cement, and the lower layer is polymer gel.

[0070] In some embodiments, after the carbon dioxide injection is completed, a composite sealing layer is laid in the geological storage area to form a sealing layer structure, specifically comprising:

[0071] Adding carbon nanotube reinforcement to nano-modified cement produces a nano-modified cement layer with high strength and improved anti-permeability.

[0072] The polymer gel is evenly coated below the nano-modified cement layer to form a double-layer composite sealing structure; the polymer gel adopts pH-responsive polyacrylamide.

[0073] In some embodiments, after issuing the warning signal, the method further includes:

[0074] Determine 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 the injection of the plugging agent; the second-level early warning is to start the suction recovery.

[0075] In summary, this application has the following technical effects:

[0076] 1. Accurately locate leaks and quantify leakage volume: By strategically placing high-precision pressure sensors, temperature sensors, and gas concentration sensors within the coal seam, on the top and bottom sealing layers, and combining them with intelligent algorithms to analyze monitoring data, we can quickly and precisely locate CO2 leaks and accurately calculate leakage volume. This provides a key basis for targeted plugging and leak control efforts, significantly improving the timeliness and effectiveness of leak handling.

[0077] 2. Real-time dynamic monitoring of leaks: Building an efficient data acquisition, transmission, and processing system, using advanced wireless transmission technology and high-speed data processing algorithms, significantly shortens data transmission and processing time, enabling real-time dynamic monitoring of CO2 leaks. This system can immediately capture leak signals and issue early warnings, buying valuable time for emergency response and effectively curbing the development of leaks.

[0078] 3. Build a comprehensive monitoring system: A comprehensive CO2 leakage monitoring system will be established, taking into account multiple factors, including geological structure, coal seam characteristics, ambient temperature and humidity, and storage system operating parameters. Through the integration and analysis of multi-source data, leakage risk levels can be accurately assessed, leakage trends can be predicted in advance, and scientific and reasonable prevention and response strategies can be formulated to ensure the safety and stability of CO2 storage.

[0079] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, 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, they should be considered to be within the scope of this specification.

[0080] This document uses specific examples to illustrate the principles and implementation methods of this application. The description of the above examples is only intended to help understand the method and core concept of this application. At the same time, for those skilled in the art, based on the concept of this application, there may be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting this application.

Claims

1. A leakage monitoring, gas injection and storage system for geological storage of carbon dioxide, characterized in that: include: A multi-stage gas injection device, consisting of a network of gas injection pipelines with distributed gas injection holes, used to inject carbon dioxide gas into different depths in the geological storage area; The multi-stage gas injection device includes at least two stages of gas injection pipelines; the diameter of the gas injection holes in each stage of the gas injection pipeline is d∈[2,10]mm, and the spacing is l∈[20,50]cm; when the permeability k>10mD, d=2mm and l=50cm; when k<1mD, d=10mm and l=20cm; the pressure bearing capacity of the gas injection pipeline is ≥50MPa; the gas injection pipeline is connected to the adjacent gas injection pipeline by welding or flange connection; the gas injection holes adopt a conical diffusion structure; the inlet diameter d1 and outlet diameter d2 of the gas injection holes satisfy d2 / d1∈[1.5-2.0]; the hole walls of the gas injection holes are coated with a nano-hydrophobic coating; 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 low pressure. When the coal seam pressure reaches a certain threshold, the second-stage gas injection pipeline is opened. An intelligent monitoring system, including pressure sensors, temperature sensors, and concentration sensors deployed at different depths within the geological storage area; A sealing layer structure, made of high-strength, low-permeability materials, used to seal the boundaries of the geological storage area; A central controller, connected to the intelligent monitoring system, is used to perform gas injection control, leakage analysis, and early warning mechanisms. The central controller is used to predict CO2 migration paths based on an LSTM-random forest hybrid model. The input to the central controller is monitoring data collected by the intelligent monitoring system, including 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 a 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.

2. A carbon dioxide geological storage leakage monitoring, gas injection and storage system according to claim 1, characterized in that: The intelligent monitoring system is composed of a distributed sensor array and a topological structure; The distributed sensor array consists of several pressure sensors, temperature sensors and CO2 concentration sensors; The topological structure is arranged according to the direction of the coal seam; in the topological structure, the interval between pressure sensors is 10 meters, the interval between temperature sensors is 15 meters, and the interval between CO2 concentration sensors is 5 meters.

3. A method for leak monitoring, gas injection and storage of carbon dioxide geological storage based on the system for leak monitoring, gas injection and storage of carbon dioxide geological storage according to any one of claims 1 to 2, characterized in that: include: Three-dimensional seismic exploration is used to obtain coal seam parameters and obtain a gas injection hole distribution model; According to the gas injection hole distribution model, based on a multi-stage gas injection device, the first stage pressure is used to inject carbon dioxide into the geological storage area; Obtaining the real-time pressure P of the geological storage area, and when the pressure of the geological storage area reaches a critical value, injecting carbon dioxide into the geological storage area using the second-level pressure; the first-level pressure is lower than the second-level pressure; When the CO2 injection is completed, a composite sealing layer is laid in the geological storage area to form a sealing layer structure; Through the intelligent monitoring system, the real-time pressure P, temperature T, and concentration C of the geological storage area are obtained in real time; When the monitoring data is abnormal, an early warning signal is issued, and leakage analysis is performed based on the central controller to predict the CO2 migration path.

4. The method for leakage monitoring, gas injection and storage of carbon dioxide geological storage according to claim 3, characterized in that: The upper layer of the composite sealing layer is nano-modified cement, and the lower layer is high molecular gel.

5. The method for leakage monitoring, gas injection and storage of carbon dioxide geological storage according to claim 4, characterized in that: When the CO2 injection is completed, a composite sealing layer is laid in the geological storage area to form a sealing layer structure, which specifically includes: Adding carbon nanotube reinforcement to nano-modified cement produces a nano-modified cement layer with high strength and improved permeability resistance; The polymer gel is evenly coated below the nano-modified cement layer to form a double-layer composite sealing structure; the polymer gel adopts pH-responsive polyacrylamide.

6. The method for leakage monitoring, gas injection and storage of carbon dioxide geological storage according to claim 5, characterized in that: After the early warning signal is issued, it also includes: Determine 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 the injection of the plugging agent; the second-level early warning is to start the suction recovery.

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