In-situ multi-depth carbon dioxide gas guiding and observation double-array test device and system

Abstract

The application provides an in-situ multi-depth carbon dioxide gas guiding and observation double-array test device and system, and relates to the technical field of gas observation.The device comprises a gas distribution system, a carbon dioxide gas guiding array, a carbon dioxide penetration observation array and a processing system.The carbon dioxide gas guiding array comprises a total gas inlet pipe and multiple gas guiding pipes.The gas inlet end of the total gas inlet pipe is connected with the gas outlet end of the gas distribution system.The gas outlet end of the gas guiding pipe is located at a specified depth in a target site.A plurality of gas explosion components are arranged at the gas outlet end of the gas guiding pipe.The carbon dioxide mixed gas penetrates to the specified depth through the plurality of gas explosion components.The carbon dioxide penetration observation array comprises multiple observation wells.The ends of different observation wells extend to different observation depths in the target site.The ends are provided with observation structures for in-situ measurement of carbon dioxide penetration data at the observation depths.The application can effectively observe the penetration of carbon dioxide in a real storage site, thereby truly reflecting the complex penetration conditions that may occur in the actual storage site.

Description

[0001] This application is a divisional application of application number 2026100430750, application date January 14, 2026, and invention title "Carbon Dioxide Permeation Observation Test Device and System". Technical Field

[0002] This invention relates to the field of gas observation technology, and in particular to an in-situ multi-depth carbon dioxide gas guiding and observation dual array experimental device and system. Background Technology

[0003] Carbon dioxide (CO2) geological sequestration technology achieves long-term storage by capturing and injecting carbon dioxide emitted from industry into deep geological structures. However, in practical engineering applications, it is necessary to strictly monitor the sequestration effect and potential leakage risks.

[0004] Shallow soils serve as the first line of defense against potential carbon dioxide leakage, making the study of their carbon dioxide permeability crucial for ensuring safe carbon dioxide sequestration. Current safety monitoring for geological carbon dioxide sequestration primarily focuses on the characteristics of deep reservoirs and caprocks, employing various monitoring methods including microseismic monitoring, pressure monitoring, and well-to-well tracing. These technologies are mainly geared towards monitoring deep reservoirs at the kilometer scale, while direct observational research on carbon dioxide transport processes in near-surface soils is relatively weak. In the field of soil carbon dioxide transport research, existing technologies largely concentrate on laboratory-scale soil column experiments or small-scale field trials, which are insufficient to accurately reflect the complex permeability conditions that may occur at actual sequestration sites. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide an in-situ multi-depth carbon dioxide gas conduction and observation dual array test device and system, which can effectively observe the permeation of carbon dioxide in a real storage site, thereby truly reflecting the complex permeation situation that may occur in the actual storage site.

[0006] In a first aspect, the present invention provides an in-situ multi-depth carbon dioxide gas conduction and observation dual-array experimental device, comprising: The gas mixing system is used to mix carbon dioxide gas with compressed air at a specified concentration ratio and pressurize it to form a carbon dioxide mixed gas. The carbon dioxide gas guiding array includes a main air inlet pipe and multiple gas guiding pipes connected to the main air inlet pipe and arranged in a distributed downward pattern along the plane of the target site. The air inlet end of the main air inlet pipe is connected to the air outlet end of the gas distribution system. The air outlet end of the gas guiding pipe is located at a specified depth within the target site. Multiple aeration components are installed at the air outlet end of the gas guiding pipe. The carbon dioxide mixed gas permeates to the specified depth through the multiple aeration components. The carbon dioxide permeation observation array includes multiple observation wells arranged in a distributed, downward direction along the plane of the target site. The ends of different observation wells extend to different observation depths within the target site, and observation structures are set at the ends. The observation structures are used to perform in-situ measurements of carbon dioxide permeation data at their respective observation depths. The processing system is connected in communication with the observation structure and is used to post-process carbon dioxide permeation data corresponding to different observation depths.

[0007] In one embodiment, the aeration component includes a filter structure consisting of multiple layers of filter screens, which disperses and filters the carbon dioxide mixture output through the air duct before releasing it into the underground soil environment at a specified depth.

[0008] In one embodiment, the observation structure includes a gas-penetrating structure and a carbon dioxide sensor; A gas-penetrating structure is installed at the end of the observation well to allow soil pore gas at the observation depth to enter the observation well. A carbon dioxide sensor, installed inside the observation well and located at the gas penetration structure, is used to measure the soil pore gas entering through the gas penetration structure in situ and generate carbon dioxide infiltration data.

[0009] In one embodiment, the gas penetration structure includes a hydrophobic filter element disposed at the carbon dioxide sensor, an aeration hole at the end of the observation well, and a filler material wrapped around the aeration hole.

[0010] In one embodiment, the observation well is used to house the data acquisition wires of the observation structure, which are used to transmit the carbon dioxide permeation data collected by the observation structure to the processing system.

[0011] In one embodiment, an adjustable flow meter is also provided at the inlet end of the air duct for adjusting and detecting the flow rate of the carbon dioxide mixture flowing through the inlet end.

[0012] In one embodiment, the aeration component further includes a backflushing cleaning module and a blockage detection unit; The blockage detection unit is used to monitor the gas pressure difference across the multi-layer filter in real time and upload the gas pressure difference value to the processing system. The processing system is configured to control the backflushing cleaning module to apply reverse pulse airflow to the multi-layer filter screen when the gas pressure difference exceeds the preset clogging threshold, in order to remove the deposits on the multi-layer filter screen.

[0013] In one embodiment, the observation structure further includes a self-calibration module disposed within the observation well; The self-calibration module includes at least one calibration gas source and a switching valve; The processing system is configured to: control the switching valve to switch the carbon dioxide sensor from being connected to the gas penetration structure to being connected to the calibration gas source according to a preset calibration cycle, so that the carbon dioxide sensor can detect the calibration gas of known concentration, and perform online calibration of the carbon dioxide sensor based on the deviation between the detection result and the known concentration.

[0014] In a second aspect, the present invention also provides an in-situ multi-depth carbon dioxide gas conduction and observation dual-array experimental system, including the in-situ multi-depth carbon dioxide gas conduction and observation dual-array experimental device provided in the first aspect, and a terminal connected to the in-situ multi-depth carbon dioxide gas conduction and observation dual-array experimental system.

[0015] Thirdly, the present invention also provides an in-situ multi-depth carbon dioxide gas conduction and observation dual-array experimental method, applied to the in-situ multi-depth carbon dioxide gas conduction and observation dual-array experimental device provided in any of the first aspects, the method comprising: Carbon dioxide gas is mixed with compressed air at a specified concentration ratio and then pressurized to form a carbon dioxide mixture. Multiple gas pipes are distributed and drooping along the plane of the target site to introduce carbon dioxide gas mixture into the target site at a specified depth. Multiple aeration components are installed at the gas outlet of the gas pipes to allow the carbon dioxide gas mixture to infiltrate the underground soil environment at the specified depth. Multiple observation wells are distributed and vertically arranged along the plane of the target site to conduct in-situ measurements of carbon dioxide permeability data at different observation depths. The ends of different observation wells extend to different observation depths within the target site, and observation structures are set at the ends. The observation structures conduct in-situ measurements of carbon dioxide permeability data at their respective observation depths. Post-processing was performed on carbon dioxide permeation data corresponding to different observation depths.

[0016] The present invention provides an in-situ multi-depth carbon dioxide gas guiding and observation dual-array experimental device and system, including a gas distribution system for mixing and pressurizing carbon dioxide gas and compressed air at a specified concentration ratio to form a carbon dioxide mixed gas; and a carbon dioxide gas guiding array including a main inlet pipe and multiple gas guiding pipes connected to the main inlet pipe and arranged in a distributed downward distribution along the plane of the target site. The inlet end of the main inlet pipe is connected to the outlet end of the gas distribution system, and the outlet end of the gas guiding pipe is located at a specified depth within the target site. Multiple aeration components are provided at the outlet end of the gas guiding pipe, and the carbon dioxide mixed gas permeates to the specified depth through the multiple aeration components. The device includes a carbon dioxide permeation observation array comprising multiple observation wells arranged in a distributed, downward orientation along the plane of the target site. The ends of different observation wells extend to different observation depths within the target site, and observation structures are installed at the ends of these wells. These observation structures are used to perform in-situ measurements of carbon dioxide permeation data at their respective observation depths. A processing system is also included, which is communicatively connected to the observation structures and is used to post-process the carbon dioxide permeation data corresponding to different observation depths. This device can effectively observe the permeation of carbon dioxide in a real storage site, thereby accurately reflecting the complex permeation conditions that may occur in the actual storage site.

[0017] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention are realized and obtained through the structures particularly pointed out in the description and the drawings.

[0018] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0019] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0020] Figure 1 A plan view of a carbon dioxide permeation observation test field provided in an embodiment of the present invention; Figure 2 A cross-sectional plan view of a carbon dioxide infiltration test field provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of a carbon dioxide explosion head provided in an embodiment of the present invention; Figure 4 A downhole profile of a carbon dioxide observation well provided in an embodiment of the present invention; Figure 5 A schematic diagram of a carbon dioxide permeation observation device provided in an embodiment of the present invention; Figure 6 This is a data acquisition architecture diagram of a carbon dioxide permeation observation device provided in an embodiment of the present invention.

[0021] Icons: 1-Main air inlet pipe; 2-Air guide assembly; 3-Pressure regulating valve; 4-Observation well; 5-Data acquisition wire; 21-Air guide pipe; 22-Aeration component; 23-Adjustable flow meter; 221-Connector; 222-Multi-layer filter screen; 41-Gas penetration structure; 42-Carbon dioxide sensor; 411-Hydrophobic filter element; 412-Aeration hole; 413-Filling material. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] Currently, existing technologies are insufficient to accurately reflect the complex permeation conditions that may occur at actual storage sites. Therefore, this invention provides a carbon dioxide permeation observation test device and system that can effectively observe the permeation of carbon dioxide at actual storage sites, thereby accurately reflecting the complex permeation conditions that may occur at actual storage sites.

[0024] To facilitate understanding of this embodiment, a detailed description of a carbon dioxide permeation observation experimental device disclosed in this embodiment of the invention will be provided first. This device includes: a carbon dioxide gas guiding array and a carbon dioxide permeation observation system, both suspended vertically within the target site; wherein, Carbon dioxide gas guiding array: used to introduce carbon dioxide mixture into the underground area of ​​the target site so that the carbon dioxide mixture can permeate within the underground area; Carbon dioxide permeability observation system: includes a carbon dioxide permeability observation array for observing carbon dioxide permeability data at different observation depths in the underground area, and a processing system connected to the carbon dioxide permeability observation array for post-processing of carbon dioxide permeability data.

[0025] This device can effectively observe the permeation of carbon dioxide in a real storage site, thus accurately reflecting the complex permeation situation that may occur in the actual storage site.

[0026] For ease of understanding, this embodiment of the invention provides a specific structure of a carbon dioxide permeation observation experimental device, see [link to documentation]. Figure 1 The diagram shows a plan layout of a carbon dioxide infiltration test site, and... Figure 2 The diagram shows a cross-sectional plan of a carbon dioxide infiltration test field.

[0027] In one embodiment, the carbon dioxide permeation monitoring device is arranged within a target site, which may be referred to as a test site. The carbon dioxide gas guiding array includes: multiple main inlet pipes 1, each main inlet pipe 1 being connected to the inlet end of multiple gas guiding components 2. The outlet ends of the gas guiding components 2 are located at a designated depth in the underground area of ​​the test site. A pressure regulating valve 3 is provided at the inlet end of the main inlet pipe 1. For an application example, please refer to [link to application example]. Figure 1 The test site measures 25 meters north-south and 23 meters east-west. Air-guiding components (2) are arranged at 2.5-meter intervals. Figure 1 The system uses circles filled with different colors to represent gas guiding components (with gas guiding components of the same color connected to the same main air intake pipe). There are a total of nine columns and nine rows. Pre-set, every three columns form a group with three main air intake pipes, allowing for the introduction of carbon dioxide gas of the same concentration or different concentrations. Based on this structure, mixed gases of the same or different concentrations of carbon dioxide can be introduced into multiple main air intake pipes. The carbon dioxide mixture is transported to the gas guiding pipes through the inlet end connected to the main air intake pipe, and then guided to a designated depth in the underground area by an explosion component installed at the outlet end of the gas guiding pipe.

[0028] Furthermore, the gas guiding assembly 2 includes a gas guiding pipe 21 and an aeration component 22 disposed at the outlet end of the gas guiding pipe 21. The gas guiding pipe 21 is used to transport carbon dioxide mixed gas, and the aeration component 22 is used to release the carbon dioxide mixed gas to a specified depth. The aeration component 22 can also be called an aeration head. Multiple aeration heads can be installed on a single gas guiding pipe, and each aeration head can also be equipped with an adjustable flow meter to collect the gas flow rate corresponding to each aeration head. That is, the gas guiding pipes are laid out on the site according to a 2.5-meter spacing rule, and the aeration heads are installed at a height of 2 meters (e.g., Figure 2 (As shown).

[0029] Furthermore, this embodiment of the invention provides a specific structure for an aeration head, which includes a connector 221 and a multi-layer filter screen 222. The connector 221 is used to fix it to the outlet end of the air guide pipe; the multi-layer filter screen 222 is used to filter the carbon dioxide mixture gas transported by the air guide pipe and release it to a specified depth. See also Figure 3 The diagram shows a carbon dioxide aeration head, with stainless steel connectors and a double-layer filter screen.

[0030] Please continue reading Figure 2The air guiding assembly also includes an adjustable flow meter 23 disposed at the air inlet end of the air guiding pipe 21, for adjusting and detecting the flow rate of the carbon dioxide mixed gas flowing through the air inlet end.

[0031] Furthermore, in the experimental scenario of underground carbon dioxide geological sequestration or soil carbon flux monitoring, a distributed gas-conducting pipe array has been deployed below the surface of the target site according to a pre-defined layout. The end of each gas-conducting pipe (i.e., the gas outlet) is located at a designated depth (e.g., different depth layers such as 5 meters, 10 meters, and 15 meters underground), and an aeration component is installed at the gas outlet. The gas distribution system mixes carbon dioxide and compressed air at a specified concentration ratio, pressurizes it, and then delivers it to each gas-conducting pipe through the main air intake pipe. The carbon dioxide mixture is finally released into the underground soil environment through the aeration component. At the same time, the observation well array collects carbon dioxide infiltration data in situ at different depths through the observation structure and uploads it to the processing system for post-processing.

[0032] During the aforementioned long-term operation, fine particulate matter in the underground soil environment (such as clay particles, silt, organic debris, etc.) and dissolved minerals in the groundwater (such as calcium carbonate precipitates) gradually deposit and adhere to the multi-layer filter screen of the aeration component as gas continuously permeates. This leads to a decrease in filter screen porosity and an increase in gas flow resistance, thereby affecting the permeation rate and distribution uniformity of the carbon dioxide mixture, ultimately reducing the accuracy and reliability of the experimental data. To address this issue, this solution integrates a backflushing cleaning module and a clogging detection unit into the aeration component, enabling real-time monitoring and automatic cleaning of the filter screen clogging status. The clogging detection unit monitors the gas pressure difference across the multi-layer filter screen in real time and uploads the gas pressure difference value to the processing system. The processing system is configured to: when the gas pressure difference exceeds a preset clogging threshold, control the backflushing cleaning module to apply a reverse pulse airflow to the multi-layer filter screen to remove the deposits on the multi-layer filter screen.

[0033] In this embodiment, the aeration component is installed at the outlet end of the air duct, and its overall structure, along the gas flow direction, includes, in sequence: an air inlet section, a flow equalization chamber, a multi-layer filter assembly, a backflushing cleaning module, a blockage detection unit, and an outlet end cover. Wherein: (1) Inlet section: It is sealed to the outlet end of the gas guide pipe by means of thread or flange connection to ensure that the carbon dioxide mixture enters the explosion component without leakage.

[0034] (2) Flow equalization chamber: It is a hollow cylindrical chamber with a flow guide cone or flow equalization plate inside. Its function is to evenly distribute the concentrated airflow from the air guide tube to the entire windward side of the filter screen, so as to avoid local airflow concentration and premature blockage of the filter screen.

[0035] (3) Multi-layer filter assembly: i.e., "a filter structure composed of multiple layers of filter mesh". In this embodiment, the multi-layer filter assembly is composed of three layers of filter mesh with different pore sizes stacked sequentially along the airflow direction: the first layer (windward side) is a coarse filter mesh with a pore size range of 200μm to 500μm, made of 316L stainless steel woven mesh, used to intercept larger soil particles; the second layer is a medium filter mesh with a pore size range of 50μm to 200μm, made of sintered metal fiber felt, used to intercept medium-sized particles; the third layer (leeward side) is a fine filter mesh with a pore size range of 10μm to 50μm, made of polytetrafluoroethylene (PTFE) microporous membrane, used to intercept fine particles and also has a hydrophobic function to prevent groundwater vapor from condensing on the filter mesh surface to form a liquid film that blocks air. The three layers of filter mesh are pressed and fixed together by metal pressure rings and sealing gaskets to form a detachable structure for easy maintenance and replacement.

[0036] (4) The pore size gradient design of the three-layer filter screen results in a graded interception distribution of particles within the filter structure, from coarse to fine. Coarse particles are intercepted on the surface of the first layer, medium-sized particles enter the second layer, and fine particles are intercepted by the third layer. This graded interception mechanism effectively extends the overall service life of the filter structure because the coarse filter screen bears most of the particle interception load, protecting the subsequent fine filter screen from rapid clogging. At the same time, a certain distance (e.g., 2mm to 5mm) is maintained between each layer of filter screen, forming an interlayer buffer space, providing a channel for the shedding and discharge of particles during backflushing cleaning. In addition, the design of the flow equalization chamber ensures that the airflow is evenly distributed to all areas of the windward side of the filter screen, avoiding local over-speed penetration and local preferential clogging caused by uneven airflow distribution, and ensuring the effective utilization rate of the entire filter screen cross-section. The three-layer filter screen adopts a detachable compression structure. When the filter screen reaches the end of its service life or becomes irreversibly clogged, the damaged layer can be replaced individually, reducing maintenance costs.

[0037] (5) Clogging Detection Unit: The clogging detection unit is used to monitor the gas pressure difference across the multi-layer filter in real time and upload the gas pressure difference value to the processing system. Specifically, the clogging detection unit includes: The first pressure sensor (upstream pressure sensor) is installed inside the flow equalization chamber, located on the windward side (i.e., the inlet side) of the multi-layer filter assembly. It is used to measure the gas pressure value P1 on the inlet side of the filter in real time. The sensor probe is connected to the inside of the flow equalization chamber through a stainless steel pressure-sensing tube. The end of the pressure-sensing tube is equipped with a dustproof filter to prevent soil particles from entering the sensor's sensitive element. The second pressure sensor (downstream pressure sensor) is installed inside the outlet end cap, located on the leeward side (i.e., the outlet side) of the multi-layer filter assembly. It is used to measure the gas pressure value P2 on the outlet side of the filter in real time. This sensor has the same model, range, accuracy, and sampling frequency as the first pressure sensor to ensure the comparability and synchronization of the pressure measurements on both sides. The sensor probe is connected to the internal space of the outlet end cap through another stainless steel pressure-sensing tube, the end of which is also equipped with a dustproof filter.

[0038] As an alternative or supplementary solution, a differential pressure transmitter can also be used directly, with its high-pressure side interface connected to the flow equalization chamber (upstream of the filter screen) and its low-pressure side interface connected to the outlet end cap (downstream of the filter screen), directly outputting the differential pressure signal ΔP between the two sides.

[0039] Signal acquisition and transmission module: Electrically connected to the first and second pressure sensors (or differential pressure transmitters), this module acquires pressure signals and converts them into digital signals. It incorporates a microcontroller (MCU) that uses an analog-to-digital converter (ADC) to acquire pressure data at a preset sampling frequency and transmits the data to the ground-based processing system via a data acquisition cable according to a preset communication protocol (such as Modbus RTU). Communication can be via wired RS485 transmission or by integrating a wireless communication unit (such as LoRa or 4G / 5G modules) within the signal acquisition module for wireless long-distance transmission of pressure data.

[0040] Methods for obtaining gas pressure difference values: The processing system obtains gas pressure difference values ​​in the following ways: (a) If a two independent pressure sensor scheme is adopted, the processing system receives real-time pressure values ​​P1 and P2 from the first pressure sensor and the second pressure sensor, and calculates the gas pressure difference ΔP=P1-P2 (unit: kPa).

[0041] (b) If a differential pressure transmitter scheme is adopted, the processing system directly receives the differential pressure value ΔP output by the differential pressure transmitter.

[0042] (c) To eliminate measurement noise, the processing system performs sliding window averaging filtering on the continuously acquired differential pressure values. The sliding window width N is set to 10 sampling points (corresponding to a sampling duration of 10 seconds at a sampling frequency of 1Hz), and the filtered differential pressure value ΔP_(filtered) is the arithmetic mean of the N sample values ​​within the window. This filtering process effectively suppresses the fluctuations in differential pressure values ​​caused by instantaneous fluctuations in gas flow or sensor electronic noise, providing a stable input signal for subsequent blockage detection.

[0043] (6) Backflush Cleaning Module: The backflush cleaning module is used to apply reverse pulsed airflow to the multi-layer filter screen when the filter screen becomes clogged, in order to remove the deposits on the multi-layer filter screen. This module specifically includes: High-pressure gas storage tank: Located near the ground gas distribution system or directly integrated inside the aeration component (when the size of the aeration component allows), it is used to store high-pressure cleaning gas, which can be compressed air or inert gas (such as nitrogen).

[0044] Backflush line: This is an independent high-pressure gas delivery line. One end is connected to the outlet of the high-pressure gas storage tank, and the other end extends into the interior of the aeration component and connects to the leeward side (i.e., the outlet side) of the multi-layer filter assembly. The backflush line is laid along the outer or inner wall of the gas guide pipe, or it can be housed together with the data acquisition wires in the observation well.

[0045] Electromagnetic pulse valve: Installed on the backflush line, located inside or near the aeration component, it controls the opening, closing, and pulse duration of the reverse pulse airflow. The electromagnetic pulse valve is a normally closed 2-position 2-way solenoid valve. The control line of the electromagnetic pulse valve is connected to the processing system via a data acquisition cable, and the processing system outputs control signals to drive the opening and closing of the electromagnetic pulse valve.

[0046] Backflush nozzles: Located inside the aeration component, on the leeward side of the multi-layer filter assembly, with their outlets facing the leeward side of the multi-layer filter. Backflush nozzles can be designed as a single central nozzle or multiple nozzles arranged in a ring array to ensure uniform coverage of the entire filter surface by reverse pulsed airflow. The nozzle outlet shape can be designed as fan-shaped, conical, or flat to optimize airflow coverage and impact force distribution.

[0047] Based on the above structure, the processing system is configured to: when the gas pressure difference exceeds a preset clogging threshold, control the backflushing cleaning module to apply a reverse pulse airflow to the multi-layer filter screen to remove the deposits on the multi-layer filter screen. The specific control logic of the processing system in this embodiment is detailed below: I. Preset of blocking threshold: Preset blockage threshold It is not a fixed value, but is determined based on a combination of the following factors: Initial pressure difference of the filter screen With the filter screen brand new and clean, a carbon dioxide mixture is introduced at the rated flow rate, and the initial pressure difference across the filter screen is measured. This value reflects the inherent flow resistance of the filter screen itself.

[0048] Allowable differential pressure increment The allowable pressure difference increment is determined based on the maximum permissible decrease in gas permeation rate as determined by the experiment. For example, when an increase in the filter pressure differential causes the gas permeation rate to decrease to 80% of the initial rate, the corresponding pressure differential increment is the allowable pressure differential increment. This can be obtained through preliminary calibration tests.

[0049] Blockage threshold .

[0050] In practical engineering applications, the clogging threshold It is usually set to the initial differential pressure value. The clogging threshold can be 2 to 3 times higher. For example, if the initial differential pressure of a brand-new clean filter at rated flow is 5 kPa, the clogging threshold can be set to 10 to 15 kPa. This threshold parameter is stored in the non-volatile memory of the processing system and can be modified through the human-machine interface of the terminal.

[0051] II. Real-time monitoring and congestion assessment: The processing system receives the gas pressure difference value ΔP from the blockage detection unit at a preset sampling period (e.g., every 1 second). The processing system continuously compares the current pressure difference value with a preset blockage threshold. Comparison: If If the filter is determined to be in normal working condition, the system will continue monitoring without triggering backflushing for cleaning. If the filter is found to be clogged, the system will trigger a backflushing cleaning procedure.

[0052] To avoid false triggers caused by instantaneous airflow fluctuations, the processing system incorporates a "continuous over-threshold confirmation" mechanism in its judgment logic: a genuine blockage event is only identified and backflushing is triggered when the differential pressure value continuously exceeds the blockage threshold for a preset confirmation period (e.g., 5 consecutive seconds, meaning 5 consecutive sampling points all satisfy ΔP ≥ ΔP_(threshold)). If the differential pressure value falls back below the threshold within the confirmation period, the trigger judgment is canceled, and normal monitoring continues.

[0053] III. Execution of the backflushing cleaning procedure: Once the processing system determines that the filter is clogged and triggers the backflushing cleaning procedure, follow these steps: Step 1: The processing system sends an opening control signal to the electromagnetic pulse valve via a data acquisition wire. Step 2: Upon receiving the opening signal, the electromagnetic pulse valve opens rapidly within less than 50ms. High-pressure clean gas from the high-pressure storage tank is released through the backflush pipeline and the electromagnetic pulse valve, via the backflush nozzles, towards the leeward side of the multi-layer filter. Step 3: The reverse pulse airflow impacts the multi-layer filter in the opposite direction to the normal carbon dioxide mixture permeation. The high-pressure airflow penetrates from the leeward side of the filter to the windward side, applying reverse shear and impact forces to soil particles, mineral deposits, and other adhering substances on the filter fiber surface and within the pores, causing them to detach from the filter. Step 4: After the electromagnetic pulse valve remains open for a preset pulse duration (e.g., 0.2 to 0.5 seconds), the processing system sends a closing control signal, closing the electromagnetic pulse valve and ending this reverse pulse airflow injection. Step 5: After the backflush pulse ends, the system waits for a preset recovery time (e.g., 10 to 30 seconds) to allow the airflow inside the aeration component to return to a stable state. Then, the differential pressure value is read again to evaluate the backflush cleaning effect.

[0054] IV. Evaluation and Adaptive Adjustment of Backflushing Cleaning Effect: After each backflushing cleaning cycle, the system evaluates the cleaning effect and adaptively adjusts the backflushing parameters based on the evaluation results. If the pressure differential value recovers to near its initial value after backflushing... The level (e.g., pressure difference after backflushing ≤ 1.2 times) If the cleaning effect is good, the current backflushing parameters should be maintained. If the pressure differential decreases after backflushing but is still significantly higher than normal, the cleaning effect is considered good. (For example, the pressure difference after backflushing is >1.5 times) If the cleaning effect is insufficient, the system will automatically adjust the backflushing parameters the next time backflushing cleaning is triggered. For example, it may extend the pulse duration (from 0.2 seconds to 0.4 seconds) or increase the number of pulses (from 1 to 3) to enhance the cleaning effect. This adaptive adjustment mechanism allows the backflushing cleaning module to dynamically optimize the cleaning strategy according to the actual degree of clogging of the filter, maximizing the conservation of high-pressure gas consumption while ensuring the cleaning effect.

[0055] The automatic backflush structure for the aeration component and the in-situ self-calibration structure for the observation well sensor of this invention are not direct transplants of commonly known components in the fields of water treatment aeration and industrial flue gas monitoring. This structure has at least the following technical effects: First, this invention is buried underground in a saturated, high-humidity environment. Clay and silt form highly adhesive mud films when exposed to water, while groundwater minerals precipitate hard carbonate deposits. The adhesion of these deposits is far greater than in water or flue gas conditions, making a single-layer filter extremely prone to rapid and complete blockage. Therefore, this invention innovatively employs a three-layer gradient pore size tiered filter, combined with continuous differential pressure monitoring and adaptive variable-duration pulse backflushing, specifically addressing the problem of complex blockage caused by moist clay. General backflushing devices lack tiered filtration and adaptive backflushing logic. Second, the air-guiding array and observation wells of this invention are all pre-buried underground, with testing periods lasting several years. Excavation and removal of equipment would damage the original soil pore structure and interfere with the CO2 seepage field, making frequent manual maintenance impossible. Therefore, this invention incorporates an underground built-in self-calibration module. A three-way switching valve switches the standard gas source to complete in-situ calibration without removing the sensor. Backflushing cleaning is automatically triggered by differential pressure, requiring no human intervention throughout the process. General calibration and backflushing equipment lacks the necessary deep underground burial and maintenance-free design. Third, this invention is a distributed dual-array coupling system, requiring synchronous control of multi-point stratified gas supply, synchronous acquisition of concentration data at multiple depths, automatic start and stop of gas distribution based on seepage steady state, and backflushing / calibration actions that do not interfere with concentration field measurements. In summary, the functional modules of this invention are specifically designed with constraints for long-term in-situ seepage tests in CCS underground soil, enabling long-term, high-precision, and synchronous CO2 seepage observation effects that are unattainable by existing technologies.

[0056] In one embodiment, the carbon dioxide permeability observation array includes multiple observation wells 4 at different observation depths. An observation structure is located at the end of each observation well 4. The observation well 4 houses the data acquisition wires of the observation structure. The observation structure is used to observe carbon dioxide permeability data at its respective observation depth, and the data is transmitted to the processing system via the data acquisition wires 5. For an example, please continue to refer to... Figure 1 and Figure 2 Pre-buried observation wells 4 (0.5, 1.5, and 2.5 meters from the ground) are set at three observation depths to observe the diffusion of carbon dioxide in different layers above, middle, and below the aeration layer after its release. Observation well 4 adopts in-situ measurement, and the measurement data is collected uniformly in the data acquisition room via a guide wire. It is responsible for the data collection and overall control of the aeration control center throughout the entire experiment.

[0057] Further, see Figure 4 The diagram shows a downhole profile of a carbon dioxide observation well. The observation structure includes a gas penetration structure 41 and a carbon dioxide sensor 42. The gas penetration structure 41 is used to allow gas at the observation depth to penetrate into the observation well 4, such as... Figure 4As shown, the gas penetration structure 41 includes a hydrophobic filter element 411 located at the carbon dioxide sensor 42, an aeration hole 412 at the end of the observation well 4, and a filler 413 surrounding the aeration hole 412. The carbon dioxide sensor 42 is used to detect the carbon dioxide permeation data corresponding to the gas in the observation well 4. Optionally, the carbon dioxide sensor 42 can be replaced with other carbon dioxide concentration measuring instruments. Throughout the experimental research process, the selection of carbon dioxide concentration measuring instruments and the establishment of the measurement system are crucial. Considering research objectives, testing accuracy, and funding, it is advisable to independently develop or jointly develop wide-range, high-resolution product equipment (requiring an instrument range of 0-200,000 ppm and a resolution of 1 ppm) to achieve wide-frequency, high-precision performance of the monitoring system and improve the overall simulation experiment capability.

[0058] In carbon dioxide geological sequestration or soil carbon flux monitoring experiments, a distributed array of observation wells has been deployed at the target site according to a pre-defined layout. Each well extends to different observation depths (e.g., 3 meters, 8 meters, 15 meters underground), with observation structures installed at the ends. During long-term in-situ monitoring, the carbon dioxide sensor is continuously exposed to a complex underground environment characterized by high temperature and humidity, dust, and corrosive gases (such as hydrogen sulfide and ammonia). The sensor's measurement accuracy will gradually drift over time due to the following factors: First, the slow aging of the sensor's sensitive elements (such as non-dispersive infrared absorbers or electrochemical sensitive membranes) causes a shift in the response relationship between its output signal and carbon dioxide concentration; second, the cumulative contamination of sensitive elements by trace amounts of impurities in the underground environment leads to a decrease in sensitivity; third, significant seasonal fluctuations in temperature and humidity affect the operating point of the sensor's electronic components. These factors cause zero-point drift and range drift in the sensor during long-term operation. Without calibration, the accuracy and reliability of the measurement data will be significantly reduced, directly affecting the judgment of carbon dioxide permeation and diffusion patterns.

[0059] To address the aforementioned issues, this solution incorporates a self-calibration module within the observation structure of the observation well. This allows the carbon dioxide sensor to automatically perform periodic calibration in its in-situ underground environment without manual disassembly or factory recalibration, thus ensuring the accuracy of long-term monitoring data. In one embodiment, the observation structure further includes a self-calibration module housed within the observation well. The self-calibration module comprises at least one calibration gas source and a switching valve. The processing system is configured to: according to a preset calibration cycle, control the switching valve to switch the carbon dioxide sensor from being connected to the gas penetration structure to being connected to the calibration gas source, enabling the carbon dioxide sensor to detect calibration gas of known concentrations, and to perform online calibration of the carbon dioxide sensor based on the deviation between the detection result and the known concentration.

[0060] The specific structure of the self-calibration module is as follows.

[0061] (1) Calibration gas source: The calibration gas source is used to provide calibration gas of known concentration as a reference standard for calibrating the carbon dioxide sensor. In this embodiment, the calibration gas source is located on the ground or inside the observation well near the wellhead (for easy periodic replacement), and is implemented using one of the following two methods: Option 1: Pre-filled Calibration Gas Cylinders: The calibration gas source consists of one or more miniature stainless steel gas cylinders pre-filled with carbon dioxide calibration gas of known concentration. High-purity nitrogen or synthetic air is used as the balance gas, and the carbon dioxide concentration is a metrologically certified standard value. In practical applications, two calibration gas cylinders with different concentrations can be configured for dual-point calibration: a low-concentration calibration gas cylinder (e.g., 1000 ppm, close to the ambient background concentration) and a high-concentration calibration gas cylinder (e.g., 10000 ppm, close to the expected peak permeation concentration), used respectively for calibrating the sensor's zero point and range. A pressure reducing valve is installed at the cylinder outlet to reduce the output pressure to a low range of 0.1 MPa to 0.2 MPa, and a precision flow regulating valve is also provided to control the output flow rate of the calibration gas within the rated flow range required by the carbon dioxide sensor.

[0062] Option 2: Dynamic Calibration Gas Generator with Permeation Tube: The calibration gas source is a dynamic calibration gas generator with a permeation tube. This device includes a permeation tube, a constant-temperature chamber, and a dilution gas channel. The permeation tube contains liquid carbon dioxide or a high-concentration carbon dioxide source. Maintaining a constant temperature in the constant-temperature chamber, the carbon dioxide is released outward through the permeation tube wall at a constant permeation rate. The dilution gas (high-purity nitrogen) flows over the outer surface of the permeation tube at a precisely controlled flow rate, mixing with the permeated carbon dioxide to form a carbon dioxide calibration gas of known concentration. By changing the flow rate of the dilution gas, different concentrations of calibration gas can be obtained. The advantage of this option is that it can dynamically generate calibration gases of various concentrations without changing gas cylinders, making it suitable for long-term unattended operation scenarios.

[0063] (2) Switching valve: The switching valve is used to switch between the two gas passages of the carbon dioxide sensor: the first passage is connected to the gas penetration structure, which is the normal measurement state; the second passage is connected to the calibration gas source, which is the calibration state. In this embodiment, a miniature electromagnetic two-position three-way valve is selected as the switching valve, and its structure and working principle are as follows: Valve body structure: The switching valve has one common port (COM port), one normally open port (NC port, i.e., NormalClose, connected to the COM port in the power-off state), and one normally closed port (NO port, i.e., NormalOpen, connected to the COM port in the power-on state). The COM port is connected to the gas inlet of the carbon dioxide sensor via a gas pipeline; the NC port is connected to the gas penetration structure (i.e., the hydrophobic filter element and aeration hole side) via a gas pipeline, allowing the sensor to communicate with soil pore gas during normal measurement; the NO port is connected to the outlet of the calibration gas source via a gas pipeline (calibration gas delivery pipeline), allowing the sensor to communicate with the calibration gas during calibration.

[0064] Operating Principle: When the switching valve is de-energized (default state), the COM port and NC port are connected, and the carbon dioxide sensor draws soil pore gas from the gas penetration structure for measurement, which is the normal monitoring mode. When the processing system sends an energizing control signal to the switching valve, the valve activates, the COM port switches to connect with the NO port, and the carbon dioxide sensor draws calibration gas of a known concentration from the calibration gas source, entering calibration mode. After calibration, the processing system removes the energizing control signal, the switching valve returns to the de-energized state, the COM port reconnects with the NC port, and the sensor returns to the normal monitoring mode.

[0065] Installation location: The switching valve is installed inside the observation well, close to the gas inlet of the carbon dioxide sensor, to shorten the gas pipeline length and reduce the dead volume of the pipeline, ensuring that the sensor can quickly respond to the calibration gas when switching calibration modes, thus shortening the calibration stabilization time.

[0066] (3) Calibration gas delivery pipeline: The calibration gas delivery pipeline is used to deliver calibration gas from the calibration gas source to the switching valve and carbon dioxide sensor inside the observation well. This pipeline is laid along the inner wall of the observation well, with one end connected to the calibration gas source outlet on the ground and the other end connected to the NO port of the switching valve. The total length of the pipeline is determined according to the depth of the observation well (e.g., from 10 meters to 50 meters).

[0067] Based on the above structure, the processing system is configured to: according to a preset calibration cycle, control the switching valve to switch the carbon dioxide sensor from being connected to the gas penetration structure to being connected to the calibration gas source, so that the carbon dioxide sensor can detect the calibration gas of a known concentration, and perform online calibration of the carbon dioxide sensor based on the deviation between the detection result and the known concentration. In this embodiment, the specific control logic of the processing system is detailed below: I. Preset Calibration Cycle: The preset calibration cycle refers to the time interval between two adjacent calibration operations. In this embodiment, the preset calibration cycle is set as a configurable parameter stored in the non-volatile memory of the processing system, with a default value of 7 days (i.e., calibration once a week). Users can modify this parameter through the terminal's human-machine interface according to actual experimental needs, and the set range is from 1 day to 30 days.

[0068] II. Calibration procedure execution flow: When the processing system determines that the preset calibration period has been reached or a calibration event has been triggered, the online calibration procedure shall be executed according to the following steps: Step 1: Normal Measurement Pause and Switching Preparation. The processing system first records the current carbon dioxide sensor measurement value as the last normal data point before calibration and timestamps it. Then, the processing system sends an energizing control signal to the switching valve. The switching valve completes its action within 30ms, switching the COM port from being connected to the NC port (gas penetration structure side) to being connected to the NO port (calibration gas source side). At this point, the gas inlet of the carbon dioxide sensor is connected to the gas path of the calibration gas source, while the path to soil pore gas is cut off.

[0069] Step 2: Calibration Gas Introduction and Stabilization. The processing system opens the output valve of the calibration gas source (or activates the mass flow controller), allowing calibration gas of known concentration to enter the gas inlet of the carbon dioxide sensor at a preset flow rate (e.g., 300 mL / min) via the calibration gas delivery pipeline and switching valve. The carbon dioxide sensor's built-in pump (or external pump) draws in the calibration gas at the rated flow rate, and the gas flows through the sensor's sensitive element. The processing system continuously reads the output signal of the carbon dioxide sensor and monitors whether the signal has reached a stable state. The criterion for determining a stable state is: within a continuous preset time period (e.g., 30 seconds), the maximum fluctuation amplitude of the sensor's output signal does not exceed a preset stability threshold (e.g., ±1% of the reading or ±10 ppm). Once the sensor's output signal reaches a stable state, the processing system records the sensor readings at N consecutive sampling points (e.g., 10), and takes the arithmetic mean as the sensor's detection result C for the calibration gas.

[0070] Step 3: The processing system compares the sensor's detection result of the calibration gas with the known concentration of the calibration gas (this concentration value is pre-stored in the processing system's calibration parameter configuration table) and calculates the deviation between the two. Based on the deviation calculation result, the processing system determines the sensor's calibration parameters. This implementation adopts a linear calibration model, that is, it assumes that the sensor has linear response characteristics within the measurement range.

[0071] Single-point calibration mode (using only one calibration gas source): This mode assumes that the sensor's zero-point drift is small relative to its range drift, and the offset can be ignored; only the slope needs correction. The processing system divides the known concentration value by the detection result value to obtain the calibration coefficient. In subsequent normal measurements, the sensor's original output value is multiplied by this calibration coefficient to obtain the calibrated carbon dioxide concentration value.

[0072] Dual-point calibration mode (using two calibration gas sources of different concentrations): The processing system sequentially introduces low-concentration and high-concentration calibration gases into the sensor, recording the corresponding detection results. Using the two known concentration values ​​and their corresponding detection results, the calibration coefficient (slope) and calibration offset (intercept) are simultaneously calculated through two-point linear fitting. In subsequent normal measurements, the sensor's original output value is multiplied by the calibration coefficient and then added to the calibration offset to obtain the calibrated carbon dioxide concentration value.

[0073] Step 4: Application of calibration parameters and measurement recovery.

[0074] The processing system updates the calculated calibration parameters (calibration coefficients and calibration offsets) to the data processing channel corresponding to the carbon dioxide sensor. Subsequently, all raw measurement data from this sensor are corrected online using the latest calibration parameters, and the corrected data is then stored and displayed. After the calibration parameters are updated, the processing system removes the energizing control signal to the switching valve, restoring the valve to its de-energized state, and its common port is reconnected to the port of the gas penetration structure. Simultaneously, the processing system closes the output valve of the calibration gas source or stops the mass flow controller. The sensor returns to normal monitoring mode and re-draws soil pore gas from the gas penetration structure for in-situ measurement. The processing system records the timestamp of this calibration completion, calibration gas concentration, detection results, calculated calibration parameters, and original measurement values ​​before calibration, forming a complete calibration log record.

[0075] III. Handling Calibration Anomalies

[0076] During online calibration, the processing system identifies and handles the following anomalies: Calibration gas depletion: When the output pressure of the calibration gas source is lower than the preset minimum pressure threshold (e.g., 0.05 MPa, monitored by the gas cylinder outlet pressure sensor), it indicates that the calibration gas is about to be depleted. The processing system stops the current calibration operation, the switching valve returns to the normal measurement state, and sends a warning message "calibration gas source needs to be replaced" to the terminal.

[0077] Abnormal calibration detection value: When the deviation between the sensor's detection result C of the calibration gas and the known concentration C exceeds the preset reasonable deviation threshold (e.g., ±20%), it indicates that the sensor may have a serious malfunction or there is a leak in the calibration gas path. The processing system will stop the current calibration, retain the previous set of valid calibration parameters, and send an alarm message "Sensor calibration abnormal" to the terminal.

[0078] Switching valve malfunction: After sending the switching valve control signal, the processing system monitors changes in the sensor output signal to determine whether the switching valve has successfully operated. If, after sending the switching signal, the sensor output signal does not change as expected within a preset time (e.g., 60 seconds) (i.e., it does not transition from the soil pore gas concentration value to the calibration gas concentration value), the switching valve is determined to be stuck or malfunctioning. The processing system then stops calibration and sends a "switching valve malfunction" alarm.

[0079] Communication interruption: If communication between the processing system and the sensor or switching valve is interrupted during the calibration process, the processing system will automatically restore the switching valve to the power-off state (normal measurement mode) after communication is restored, and record the communication interruption event.

[0080] Furthermore, the carbon dioxide permeation observation and testing device also includes a gas mixing system, used to mix carbon dioxide gas and compressed air in a specified ratio, and then pressurize the resulting carbon dioxide mixture before delivering it to the carbon dioxide gas delivery array. In specific implementation, the gas mixing system mixes high-purity carbon dioxide gas with compressed air to the required concentration, pressurizes it to 0.5 MPa, and then introduces it into a pre-buried underground aeration head through an 8 mm conduit, achieving pressurized tissue permeation of carbon dioxide gas of known concentration underground.

[0081] Further, see Figure 5 The diagram shows a schematic of a carbon dioxide permeation observation device. The processing system of this invention may include a data acquisition center connected to a data acquisition cable 5, and the data acquisition center is communicatively connected to a server. The server is communicatively connected to a terminal, which displays the post-processing results of the carbon dioxide permeation data. Based on this, see [reference needed]. Figure 6 The diagram shows a data acquisition architecture for a carbon dioxide permeation observation device. The data acquisition center can acquire data uploaded by carbon dioxide sensors (referred to as measurement points) installed on each observation well, as well as data uploaded by adjustable flow meters installed on each gas delivery pipe, for post-processing.

[0082] In one embodiment, the processing system is also communicatively connected to the gas distribution system and configured to: acquire carbon dioxide permeation data uploaded in real time by the carbon dioxide permeation observation array; calculate the permeation rate change trend of the current permeation stage based on the carbon dioxide permeation data; when the permeation rate change trend indicates that the permeation has reached a preset steady-state condition, generate a gas delivery pause command to control the gas distribution system to stop supplying carbon dioxide mixed gas to the carbon dioxide gas delivery array; during the gas delivery pause, continuously monitor the carbon dioxide permeation data, and when the carbon dioxide permeation data indicates that the permeation state begins to decay, generate a gas delivery recovery command to control the gas distribution system to resume supplying carbon dioxide mixed gas to the carbon dioxide gas delivery array.

[0083] The carbon dioxide permeation monitoring device provided in this invention can effectively monitor the permeation of carbon dioxide in actual storage sites, thereby accurately reflecting the complex permeation conditions that may occur in actual storage sites and providing support for subsequent applications. Specifically: (1) Ensure the integrity and accuracy of experimental data, laying the foundation for scientific research: (1.1) The transport and diffusion of carbon dioxide released underground in the soil is influenced by a combination of factors, including soil pore structure (porosity, permeability), water content, texture (sandy / clay), organic matter content, and surface meteorological conditions (temperature, humidity, wind speed, precipitation). The process is heterogeneous, dynamic, and concealed. Without systematic monitoring, data fragmentation or even distortion will occur. (1.2) Soil is a typical heterogeneous porous medium. The clay content and pore connectivity of different areas in the same test site may vary greatly. Carbon dioxide will diffuse rapidly along the dominant channels. It is impossible to capture the complete concentration field distribution by monitoring only a few fixed points. (1.3) Precipitation compresses the gas space in soil pores and reduces the diffusion rate of carbon dioxide, while high temperature accelerates the movement of gas molecules. Dynamic changes in meteorological conditions can cause real-time changes in carbon dioxide transport paths. Multiple parameters need to be monitored simultaneously to clarify the response relationship between meteorology, soil and CO2 transport.

[0084] The carbon dioxide permeation observation device provided in this invention can construct a three-dimensional dataset of time, space, and parameters by acquiring data from multiple dimensions (concentration, humidity, temperature, pressure), multiple spatial points (different distances / depths around the release point), and high frequency (minute-level / hour-level). This avoids deviations in research conclusions due to missed key nodes or missing parameters, and ensures that the experimental data can support subsequent mechanism analysis and pattern summarization.

[0085] (2) Analysis of the core mechanism and main controlling factors of carbon dioxide transport and diffusion in soil: The core objective of the carbon dioxide infiltration monitoring device is to reveal the diffusion path, rate decay law and boundary influence of carbon dioxide in soil under different underground release conditions. The analysis of these mechanisms must rely on the support of system monitoring data.

[0086] (2.1) Quantitative diffusion characteristic parameters: By monitoring the carbon dioxide concentration change curves over time at different distances (e.g., 0.5m, 1m, 3m, 5m) and different depths (e.g., 1m, 2m, 3m) around the release point, key parameters such as diffusion coefficient, concentration gradient, and radius of influence can be calculated, clarifying how the carbon dioxide concentration decay rate changes as the distance and depth increase. (2.2) Identify the main controlling factors: Simultaneously monitor parameters such as soil moisture content (e.g., when the moisture content of clay soil increases, the carbon dioxide diffusion rate decreases) and surface wind speed (increased wind speed accelerates the escape of carbon dioxide from the surface). Through correlation analysis, the contribution of soil properties and external meteorological conditions to transport and diffusion can be distinguished. For example, during the dry season, carbon dioxide diffusion in sandy soil is dominated by the gas phase, but after rainfall, it becomes a water-gas two-phase blocked diffusion. (2.3) Capturing special transport phenomena: There may be capillary blockage effect (i.e., carbon dioxide diffusion is blocked in moist pores) and concentration stratification phenomenon (i.e., high concentration of carbon dioxide accumulates in low-lying soil due to density difference). These phenomena can only be discovered through spatial data of high-density monitoring points and cannot be verified by theoretical deduction alone.

[0087] (3) Verify and calibrate the soil carbon dioxide transport prediction model to improve simulation reliability: Current numerical models for soil carbon dioxide transport are mostly based on the assumption of ideal homogeneous soil, which deviates significantly from actual heterogeneous soil. The carbon dioxide infiltration observation device provided in this embodiment of the invention provides experimental basis for model verification and optimization.

[0088] (3.1) Model parameter calibration: Input the measured data such as soil porosity and diffusion coefficient obtained from monitoring into the model to replace the empirically estimated parameters and solve the simulation deviation caused by inaccurate model input parameters; (3.1) Simulation result calibration: Compare the carbon dioxide concentration distribution predicted by the model with the actual concentration field monitored, and correct the module parameters in the model related to the carbon dioxide concentration distribution. For example, for the simulation deviation in the interface area between sandy soil and clay soil, adjust the interface diffusion resistance coefficient through measured data so that the model can more accurately predict the range of carbon dioxide transport under complex soil conditions.

[0089] Through verification and calibration, the carbon dioxide permeation monitoring device provided in this embodiment of the invention can significantly improve the reliability of soil carbon dioxide transport prediction models, providing a precise tool for subsequent "prediction of carbon dioxide leakage risk in shallow soil of CCS projects". For example, it can predict how long it will take for carbon dioxide to diffuse to the surface or sensitive areas in shallow soil after a leak in the storage body.

[0090] (4) Supporting the research and development and verification of soil carbon dioxide leakage monitoring technology, serving engineering applications: In CCS projects, if underground carbon dioxide breaks through the caprock, it will first enter the shallow soil. Therefore, the shallow soil is a key early warning layer for carbon dioxide leakage. The carbon dioxide permeability observation device provided in this embodiment can serve as a "testbed" for soil carbon dioxide leakage monitoring technology, directly serving the needs of engineering applications: (4.1) Screening efficient monitoring methods: Different monitoring technologies (such as static soil gas sampling, in-situ fiber optic sensing, and portable carbon dioxide analyzer for real-time monitoring) are deployed simultaneously in the test field. By manually controlling the release intensity, the detection limits (such as whether it can identify a concentration anomaly of 0.1% vol), response time (such as how long after a concentration anomaly can an early warning be triggered), and spatial positioning accuracy (such as whether it can locate the leak point within ±0.5m) of different technologies are compared to screen out a low-cost, highly sensitive, and easy-to-maintain engineering monitoring scheme. (4.2) Establishing early warning thresholds: By monitoring the background, abnormal, and dangerous concentration ranges of soil carbon dioxide under different release intensities over a long period, graded early warning thresholds can be established. For example: background value 0.04% vol, abnormal value 0.5% vol, and dangerous value 5% vol, providing a directly referable standard for soil monitoring and early warning in CCS projects.

[0091] Based on the foregoing embodiments, this embodiment of the invention provides a carbon dioxide permeation observation test system, including the carbon dioxide permeation observation test device provided in the foregoing embodiments, and a terminal connected to the carbon dioxide permeation observation test device. The terminal can be used to display the post-processing results of carbon dioxide permeation data.

[0092] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working process of the carbon dioxide permeation observation test system described above can be referred to the corresponding process in the foregoing embodiments, and will not be repeated here.

[0093] Based on the foregoing embodiments, this invention provides an in-situ multi-depth carbon dioxide gas conduction and observation dual-array experimental method, applied to an in-situ multi-depth carbon dioxide gas conduction and observation dual-array experimental device, the method comprising: Carbon dioxide gas is mixed with compressed air at a specified concentration ratio and then pressurized to form a carbon dioxide mixture. Multiple gas pipes are distributed and drooping along the plane of the target site to introduce carbon dioxide gas mixture into the target site at a specified depth. Multiple aeration components are installed at the gas outlet of the gas pipes to allow the carbon dioxide gas mixture to infiltrate the underground soil environment at the specified depth. Multiple observation wells are distributed and vertically arranged along the plane of the target site to conduct in-situ measurements of carbon dioxide permeability data at different observation depths. The ends of different observation wells extend to different observation depths within the target site, and observation structures are set at the ends. The observation structures conduct in-situ measurements of carbon dioxide permeability data at their respective observation depths. Post-processing was performed on carbon dioxide permeation data corresponding to different observation depths.

[0094] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working process of the method described above can be referred to the corresponding process in the foregoing embodiments, and will not be repeated here.

[0095] In the description of the embodiments of the present invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in the present invention based on the specific circumstances.

[0096] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0097] Finally, it should be noted that the above-described embodiments are merely specific implementations of the present invention, used to illustrate the technical solutions of the present invention, and not to limit it. The scope of protection of the present invention is not limited thereto. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can still modify or easily conceive of changes to the technical solutions described in the foregoing embodiments within the technical scope disclosed in the present invention, or make equivalent substitutions for some of the technical features; and these modifications, changes, or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. An in-situ multi-depth carbon dioxide gas conduction and observation dual-array experimental device, characterized in that, include: The gas mixing system is used to mix carbon dioxide gas with compressed air at a specified concentration ratio and pressurize it to form a carbon dioxide mixed gas. A carbon dioxide gas guiding array includes a main air intake pipe and multiple gas guiding pipes connected to the main air intake pipe and arranged in a distributed downward pattern along the plane of the target site. The air intake end of the main air intake pipe is connected to the air outlet end of the gas distribution system. The air outlet end of the gas guiding pipe is located at a specified depth within the target site. Multiple aeration components are provided at the air outlet end of the gas guiding pipe. The carbon dioxide mixed gas permeates to the specified depth through the multiple aeration components. A carbon dioxide permeation observation array includes multiple observation wells arranged in a distributed, downward orientation along the plane of a target site. The ends of the different observation wells extend to different observation depths within the target site, and an observation structure is provided at each end. The observation structure is used to perform in-situ measurements of carbon dioxide permeation data at the observation depth it is located in. A processing system, which is communicatively connected to the observation structure, is used to post-process the carbon dioxide permeation data corresponding to different observation depths.

2. The in-situ multi-depth carbon dioxide gas conduction and observation dual-array experimental device according to claim 1, characterized in that, The aeration component includes a filtration structure composed of multiple layers of filter screens. The filtration structure is used to disperse and filter the carbon dioxide mixed gas output through the gas guide pipe before releasing it into the underground soil environment at the specified depth.

3. The in-situ multi-depth carbon dioxide gas conduction and observation dual-array experimental device according to claim 1, characterized in that, The observation structure includes a gas penetration structure and a carbon dioxide sensor; The gas penetration structure is located at the end of the observation well and is used to allow soil pore gas at the observation depth to enter the observation well. The carbon dioxide sensor is installed inside the observation well and located at the gas penetration structure. It is used to perform in-situ measurement of soil pore gas entering through the gas penetration structure and generate the carbon dioxide permeation data.

4. The in-situ multi-depth carbon dioxide gas conduction and observation dual-array experimental device according to claim 3, characterized in that, The gas penetration structure includes a hydrophobic filter element disposed at the carbon dioxide sensor, an aeration hole at the end of the observation well, and a filler material wrapped around the aeration hole.

5. The in-situ multi-depth carbon dioxide gas conduction and observation dual-array experimental device according to claim 1, characterized in that, The observation well is used to house the data acquisition conductor of the observation structure, and the data acquisition conductor is used to transmit the carbon dioxide permeation data collected by the observation structure to the processing system.

6. The in-situ multi-depth carbon dioxide gas conduction and observation dual-array experimental device according to claim 1, characterized in that, It also includes an adjustable flow meter disposed at the air inlet end of the air guide pipe for adjusting and detecting the flow rate of the carbon dioxide mixed gas flowing through the air inlet end.

7. The in-situ multi-depth carbon dioxide gas conduction and observation dual-array experimental device according to claim 2, characterized in that, The aeration component also includes a backflushing cleaning module and a blockage detection unit; The blockage detection unit is used to monitor the gas pressure difference across the multi-layer filter in real time and upload the gas pressure difference to the processing system. The processing system is configured to: when the gas pressure difference exceeds a preset blockage threshold, control the backflushing cleaning module to apply a reverse pulse airflow to the multi-layer filter screen to remove the deposits on the multi-layer filter screen.

8. The in-situ multi-depth carbon dioxide gas conduction and observation dual-array experimental device according to claim 3, characterized in that, The observation structure also includes a self-calibration module installed within the observation well; The self-calibration module includes at least one calibration gas source and a switching valve; The processing system is configured to: control the switching valve to switch the carbon dioxide sensor from being connected to the gas penetration structure to being connected to the calibration gas source according to a preset calibration cycle, so that the carbon dioxide sensor can detect a calibration gas of known concentration, and perform online calibration of the carbon dioxide sensor based on the deviation between the detection result and the known concentration.

9. An in-situ multi-depth carbon dioxide gas conduction and observation dual-array experimental system, characterized in that, It includes the in-situ multi-depth carbon dioxide gas conduction and observation dual array experimental device as described in any one of claims 1-8, and a terminal connected to the in-situ multi-depth carbon dioxide gas conduction and observation dual array experimental device.

10. A method for in-situ multi-depth carbon dioxide gas conduction and observation dual-array experiment, characterized in that, The method, applied to the in-situ multi-depth carbon dioxide gas conduction and observation dual-array experimental device according to any one of claims 1-8, comprises: Carbon dioxide gas is mixed with compressed air at a specified concentration ratio and then pressurized to form a carbon dioxide mixture. The carbon dioxide mixture is introduced into a designated depth within the target site by multiple gas pipes arranged in a distributed, downward-facing manner along the plane of the target site. The carbon dioxide mixture is then allowed to permeate into the underground soil environment at the designated depth by multiple aeration components installed at the outlet of the gas pipes. Multiple observation wells are distributed and vertically arranged along the plane of the target site to perform in-situ measurements of carbon dioxide permeability data at different observation depths. The ends of the different observation wells extend to different observation depths within the target site, and observation structures are set at the ends. The observation structures perform in-situ measurements of carbon dioxide permeability data at the observation depths they are located in. The carbon dioxide permeation data corresponding to different observation depths are post-processed.

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