Wide-range and long-period adaptive monitoring system and method for methane parameters in deep-sea methane leakage area

Abstract

The present invention relates to the technical field of methane parameter monitoring, and provides a wide-range and long-period adaptive monitoring system and method for methane parameters in a deep-sea methane leakage area. The system comprises a gas and flow field measurement unit, a controller unit, and an energy storage unit. The gas and flow field measurement unit is provided with deep-sea methane concentration sensors having different optimal methane concentration measurement ranges, and the optimal methane concentration measurement ranges are selected to cover a wide range of methane concentration intervals of a deep-sea methane leakage area, thereby improving the methane concentration measurement precision in a deep-sea methane leakage area having a special leakage background. Moreover, the gas and flow field measurement unit is also provided with a water flow velocity sensor, to obtain real-time vector flow velocity and direction change data at a measurement location. Thus, methane parameters of a deep-sea methane leakage area can be adaptively monitored, and multi-directional real-time monitoring can be carried out on flow field changes of the methane leakage area, so as to systematically reveal the correlation and spatial distribution relationship between the seabed ocean current flow field and the methane concentration gradient diffusion in the deep-sea methane leakage area.

Description

Wide-range and long-period adaptive monitoring system and method for methane parameters in deep-sea methane leakage areas Technical Field

[0001] The present invention relates to the technical field of methane parameter monitoring, and more specifically, to a wide-range, long-period adaptive monitoring system and method for methane parameters in a deep-sea methane leakage area. Background Art

[0002] Natural gas hydrates, commonly known as combustible ice, are widely found in submarine sediments along continental margins. Unlike conventional oil and gas reservoirs, natural gas hydrates lack natural entrapments and instead exist as solids cemented within sediment pores or filling cracks and cavities within the sedimentary layers, forming layers, veins, and large masses. Decomposition of natural gas hydrates reduces reservoir cementation. The accumulation of large amounts of decomposed methane and the resulting fluid flow within the reservoir can cause pore overpressure, leading to reservoir instability and landslides. Subsea landslides alter the temperature and pressure conditions in the natural gas hydrate reservoir, potentially triggering a chain reaction of decomposition of natural gas hydrates more widely. Leaked methane can enter overlying sediments, water bodies, and even the atmosphere, potentially triggering environmental and ecological problems such as ocean acidification, biodiversity loss, and global warming.

[0003] Currently, existing scientific methods are unable to precisely answer the impacts and mechanisms of natural gas hydrate formation and decomposition on the atmospheric, submarine, marine, and ecological environments, as well as the control mechanisms and dynamics of methane leakage from natural gas hydrate decomposition. Therefore, how to accurately detect methane leaks over long periods of time in deep-sea methane leak areas has become a key focus of this research.

[0004] The extreme environments of deep-sea methane leak areas are often characterized by high pressure, low temperature, and high corrosiveness. Furthermore, methane leaks in these areas are characterized by intermittent leaks, large variability in leak flux, random leak timing, and wide variations in methane concentration within the leak area. Therefore, long-term monitoring of relevant parameters in these areas is crucial for understanding the patterns of methane leaks, their impact on surrounding ecosystems, and geophysical processes such as changes in methane concentration in the overlying water layer. Existing long-term methane monitoring systems are often used in areas with high flammable gas concentrations, such as mining areas. Due to the challenges of monitoring methane leaks, such as large variations in leak flux and methane concentration in the surrounding water layer, existing single-unit methane concentration sensors often lack accuracy when exposed to both low and high methane concentrations. Therefore, the key to improving detection accuracy in methane leak areas with unique leak profiles is to collaboratively configure methane concentration sensors with different detection concentrations. Currently, a method has been proposed to improve methane concentration monitoring by jointly detecting methane concentration with multiple methane concentration sensors with different measurement ranges and then taking the average value. However, the problem that a single sensor usually has an optimal monitoring range and the methane leakage flux in deep-sea methane leakage areas varies greatly has not been properly solved. Multiple sensors are turned on and kept in working state at the same time, but there is no external power supply in the deep-sea environment, which is not conducive to achieving the work goal of long-term monitoring.

[0005] At the same time, at the location of deep-sea methane leakage, there will be changes in the seabed hydraulic flow field due to ocean current disturbances and methane eruptions. In principle, the methane concentration in the water body at the monitoring point will change with the relative position of the methane leakage port, and there will be a concentration gradient change of approximately concentric circle diffusion. However, under the influence of changes in the seabed hydraulic flow field, the spatial variation law of methane concentration diffusion needs further study.

[0006] Summary of the Invention

[0007] In order to solve the problems of low accuracy of methane parameter monitoring in deep-sea methane leakage areas and the monitoring method that does not take into account the impact of changes in the seabed flow field on methane distribution and diffusion, this application proposes a wide-range and long-period adaptive monitoring system and method for methane parameters in deep-sea methane leakage areas. It can not only adaptively monitor the methane parameters in deep-sea methane leakage areas, but also perform multi-directional real-time monitoring of flow field changes in methane leakage areas, so as to systematically reveal the correlation and spatial distribution relationship between the seabed ocean current field and methane concentration gradient diffusion in deep-sea methane leakage areas.

[0008] In order to achieve the above technical effects, the technical solutions of the present invention are as follows:

[0009] In the first aspect, the present application proposes a wide-range, long-period adaptive monitoring system for methane parameters in a deep-sea methane leakage area, the system comprising:

[0010] A gas and flow field detection unit, comprising a plurality of deep-sea methane sensors for measuring methane concentration and a water flow velocity sensor for measuring water flow velocity in different directions. The plurality of deep-sea methane sensors are arranged in a test area in a deep-sea methane leakage area, and each deep-sea methane sensor has a different optimal methane concentration detection range;

[0011] The controller unit is used to control the timing of opening and closing detection of each deep-sea methane sensor in each monitoring cycle according to the methane concentration range of the area to be tested and the different optimal methane concentration detection ranges of each deep-sea methane sensor, and is used to control the opening and closing of the water flow velocity sensor, and store the methane concentration data measured by the deep-sea methane sensor and the water flow velocity data measured by the water flow velocity sensor.

[0012] The energy storage unit is used to provide long-term power supply to the gas and flow field detection unit and the controller unit.

[0013] In the first aspect of the application, in view of the characteristics of methane leakage in deep-sea methane leakage areas, the methane concentration in the leakage area varies greatly, and there is a wide range of methane concentration intervals. In addition, the widespread use of external energy makes it impossible to take samples for a long time, and the monitoring method of taking the average value after monitoring with single sensors or multiple sensors of the same type limits the monitoring accuracy. The monitoring method for deep-sea methane leakage areas does not take into account the impact of changes in the seabed flow field on the distribution and diffusion of the test objects, and the spatial distribution law of the methane concentration gradient change has not been clarified. A wide-range and long-period adaptive monitoring system for methane parameters in deep-sea methane leakage areas is proposed, which is equipped with Deep-sea methane concentration sensors have different optimal methane concentration detection ranges. The optimal methane concentration detection range is selected to cover a wide range of methane concentrations in deep-sea methane leakage areas, improving the accuracy of methane concentration detection in deep-sea methane leakage areas with unique leakage backgrounds. Equipped with a water flow velocity sensor, it acquires real-time vector flow velocity and directional change data at the detection location. This not only enables adaptive monitoring of methane parameters in deep-sea methane leakage areas, but also multi-directional, real-time monitoring of flow field changes in methane leakage areas, facilitating the systematic revelation of the correlation and spatial distribution relationship between the submarine current field and the methane concentration gradient diffusion in deep-sea methane leakage areas. Furthermore, the energy storage unit avoids the drawback of the commonly used external function method, which makes it impossible to obtain samples over a long period of time.

[0014] Preferably, the water flow velocity sensors are arranged at 90° in the same plane to obtain bidirectional water flow velocity data in the plane where the setting points are located.

[0015] Through the above technical means, the two-way water flow velocity in the plane where the setting point is located is obtained, and then the vector flow velocity of the setting point is calculated. Combined with the methane concentration data, it lays the foundation for exploring the correlation between methane eruptions and changes in the seabed flow field in deep-sea methane leakage areas.

[0016] Preferably, the optimal methane concentration detection ranges of the deep-sea methane sensor for measuring methane concentration are C1, C2, ..., C n , n represents the number of deep-sea methane sensors, and the methane concentration range of the test area is 0 to X, X represents the upper limit of the methane concentration range, and the sum of the optimal methane concentration detection range of n deep-sea methane sensors is: C1+C2+...+C n , covering the methane concentration range of the area to be tested.

[0017] According to the above technical means, the optimal methane concentration detection range of all deep-sea methane sensors overlaps with the methane concentration range of the test area, which can meet the special conditions of the deep-sea methane leakage area where the methane concentration is unstable and has a large range of variation.

[0018] Preferably, when the system is used for wide-range and long-period adaptive monitoring of methane parameters in a deep-sea methane leakage area, several deep-sea methane sensors for measuring methane concentration simultaneously start methane concentration detection and obtain initial methane concentration data.

[0019] Preferably, the controller unit includes: a main control chip module, a storage module, and a calendar module;

[0020] The main control chip module is used to compare the initial methane concentration data obtained simultaneously by several deep-sea methane sensors with the different optimal methane concentration detection ranges of each deep-sea methane sensor. Within a monitoring cycle, the deep-sea methane sensors whose optimal methane concentration detection ranges match the initial methane concentration data obtained simultaneously are turned on, and the deep-sea methane sensors whose optimal methane concentration detection ranges do not match the initial methane concentration data obtained simultaneously are turned off.

[0021] The storage module is used to store the initial methane concentration data obtained simultaneously by a plurality of deep-sea methane sensors and the different optimal methane concentration detection ranges of each deep-sea methane sensor, and to store the water flow velocity data measured by the water flow velocity sensor;

[0022] The calendar module is used to record the monitoring period.

[0023] Through the above-mentioned technical means, by comparing the initial methane concentration data obtained simultaneously by multiple deep-sea methane sensors with the optimal methane concentration detection range of each deep-sea methane sensor stored in the main control chip module, on the basis of meeting the effect of accurate measurement in the entire concentration range, the most suitable methane concentration sensor in the current monitoring sequence is selected to be turned on, and the remaining methane concentration sensors are turned off to achieve energy saving, meet the energy supply stability and durability during short-time sequence and long-cycle operation, and also meet the needs of wide-range and long-cycle adaptive monitoring of methane parameters in deep-sea methane leakage areas.

[0024] Preferably, the controller unit further comprises: a debugging charging interface and a power management module;

[0025] The debugging and charging interface is used to pre-set parameters of the controller unit, read data, and charge the energy storage unit;

[0026] The power management module is used to manage the power supply status of the system.

[0027] Through the above technical means, the use of the controller unit is facilitated and the usability of the system proposed in this application is guaranteed.

[0028] Preferably, the system further comprises: a pressure-resistant chamber, in which the controller unit and the energy storage unit are packaged and integrated.

[0029] Through the above technical means, the self-contained design requirements of the system are met, and the controller unit of the system proposed in this application can be guaranteed to operate stably under extreme conditions in the deep sea.

[0030] Preferably, the system is placed around the central leakage vent of the deep-sea methane leakage area.

[0031] Through the above-mentioned technical means, the system is placed around the central leakage vent in the deep-sea methane leakage area. The long-period and short-time series monitoring data of methane concentration can be combined with the seabed flow field change data, and then used to study the correlation between methane concentration changes and seabed flow field changes, and study the spatial distribution law of methane concentration in the deep-sea methane leakage area.

[0032] In a second aspect, the present application proposes a method for adaptively monitoring methane parameters over a wide range and a long period in a deep-sea methane leakage area. The method is implemented based on the system for adaptively monitoring methane parameters over a wide range and a long period in a deep-sea methane leakage area, and includes the following steps:

[0033] S1: Set the upper limit of the monitoring cycle number;

[0034] S2: Obtain the methane concentration range of the vent location in the deep-sea methane leakage area;

[0035] S3: Several deep-sea methane sensors for measuring methane concentration simultaneously start methane concentration detection and obtain initial methane concentration data, and start water flow velocity sensors to measure water flow velocity;

[0036] S4: During a monitoring cycle, the initial methane concentration data simultaneously acquired by several deep-sea methane sensors are compared with the different optimal methane concentration detection ranges of each deep-sea methane sensor. The deep-sea methane sensors whose optimal methane concentration detection ranges match the initial methane concentration data are kept turned on to be in a working state and detect the methane concentration; the deep-sea methane sensors whose optimal methane concentration detection ranges do not match the initial methane concentration data are turned off to be in a dormant state.

[0037] S5: Determine whether the number of monitoring cycles reaches the upper limit. If so, output the water flow velocity data detected by the water flow velocity sensor in each monitoring cycle and the methane concentration data detected by the deep-sea methane sensor in working state in each monitoring cycle; otherwise, return to S2.

[0038] Preferably, the method further comprises:

[0039] S6: extracting water flow velocity data detected by the water flow velocity sensor in each monitoring period and methane concentration data detected by the deep-sea methane sensor in working state in each monitoring period;

[0040] S7: Time synchronization and coordinate system alignment of water flow velocity data and methane concentration data;

[0041] S8: Couple the methane concentration data with the water velocity data and perform spatial interpolation to generate a continuous data field within the monitoring range of the deep-sea methane leakage area;

[0042] S9: Correlation analysis based on continuous data fields;

[0043] S10: Perform spatial autocorrelation analysis to determine the spatial distribution between the hydraulic flow field corresponding to the water velocity data and the methane concentration gradient diffusion.

[0044] Through the above technical means, the long-period and short-time series monitoring data of methane concentration in the deep-sea methane leakage area are combined with the hydraulic flow field change data corresponding to the water flow velocity data, and then the correlation between the change of methane concentration and the change of the seabed flow field is studied, laying the foundation for studying the spatial distribution law of methane concentration in the deep-sea methane leakage area.

[0045] Compared with the prior art, the beneficial effects of the technical solution of the present invention are:

[0046] The present invention proposes a wide-range, long-period adaptive monitoring system and method for methane parameters in a deep-sea methane leakage area, comprising a gas and flow field detection unit, a controller unit, and an energy storage unit. The gas and flow field detection unit is configured with deep-sea methane concentration sensors having different optimal methane concentration detection ranges. The optimal methane concentration detection range is selected to cover a wide range of methane concentration intervals in the deep-sea methane leakage area, thereby improving the methane concentration detection accuracy in deep-sea methane leakage areas with special leakage backgrounds. The gas and flow field detection unit is also equipped with a water flow velocity sensor to obtain real-time vector flow velocity and direction change data at the detection position. This system can not only adaptively monitor the methane parameters in the deep-sea methane leakage area, but also perform multi-directional real-time monitoring of flow field changes in the methane leakage area, thereby systematically revealing the correlation and spatial distribution relationship between the submarine ocean current field and the methane concentration gradient diffusion in the deep-sea methane leakage area. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] FIG1 shows a structural diagram of a wide-range, long-period adaptive monitoring system for methane parameters in a deep-sea methane leakage area proposed in an embodiment of the present invention;

[0048] FIG2 is a schematic diagram showing the placement of multiple adaptive monitoring systems in a deep-sea methane leakage area according to an embodiment of the present invention;

[0049] FIG3 is a schematic flow chart showing a method for adaptively monitoring methane parameters over a wide range and over a long period in a deep-sea methane leakage area according to an embodiment of the present invention;

[0050] FIG4 is another schematic flow chart of a method for adaptively monitoring methane parameters over a wide range and a long period in a deep-sea methane leakage area according to an embodiment of the present invention. DETAILED DESCRIPTION

[0051] The accompanying drawings are for illustrative purposes only and are not to be construed as limiting the present application;

[0052] In order to better illustrate this embodiment, some parts of the drawings may be omitted, enlarged, or reduced, and do not represent the actual size;

[0053] It is understandable to those skilled in the art that descriptions of certain well-known contents may be omitted in the drawings.

[0054] The technical solution of the present invention is further described below with reference to the accompanying drawings and embodiments.

[0055] The positional relationships described in the drawings are for illustrative purposes only and should not be construed as limiting the present application.

[0056] Example 1 As shown in Figure 1, in this embodiment, a wide-range and long-period adaptive monitoring system for methane parameters in a deep-sea methane leakage area is proposed. Referring to Figure 1, the system includes: a gas and flow field detection unit, a controller unit and an energy storage unit, wherein the gas and flow field detection unit includes a number of deep-sea methane sensors for measuring methane concentration and a water flow velocity sensor for measuring water flow velocity in different directions. In specific implementation, a number of deep-sea methane sensors are set in the area to be tested in the deep-sea methane leakage area, and each deep-sea methane sensor has a different optimal methane concentration detection range.

[0057] The controller unit is used to control the timing of the on and off detection of each of the several deep-sea methane sensors in each monitoring cycle, based on the methane concentration range of the test area and the different optimal methane concentration detection ranges of each deep-sea methane sensor, and is used to control the on and off of the water flow velocity sensor, and store the methane concentration data measured by the deep-sea methane sensor and the water flow velocity data measured by the water flow velocity sensor. The energy storage unit is used to provide long-term power to the gas and flow field detection unit and the controller unit. In this embodiment, the energy storage unit uses a lithium battery pack. The energy storage unit avoids the defect of being unable to sample for a long period of time due to the common use of external functions. Of course, the energy storage unit is not limited to using a lithium battery pack, and can also be other types of energy storage.

[0058] In the embodiment of the present application, in view of the characteristics of methane leakage in deep-sea methane leakage areas, the methane concentration in the leakage area varies greatly, and has a wide range of methane concentration intervals. In view of the common use of external power supply, which makes it impossible to sample for a long period of time, the monitoring method of taking the average value after monitoring with a single methane concentration sensor or multiple methane sensors of the same category limits the monitoring accuracy, and the monitoring method for deep-sea methane leakage areas does not take into account the problem of the impact of changes in the seabed flow field on the distribution and diffusion of the test objects, and the spatial distribution law of the methane concentration gradient change has not been clarified, a wide-range and long-period adaptive monitoring system for methane parameters in deep-sea methane leakage areas is proposed. Specifically, deep-sea methane concentration sensors with different optimal methane concentration detection ranges are configured in the gas and flow field detection unit, and the optimal methane concentration detection ranges of the deep-sea methane sensors used to measure methane concentration are C1, C2, ..., C n , n represents the number of deep-sea methane sensors, and the methane concentration range of the test area is 0 to X, X represents the upper limit of the methane concentration range, and the sum of the optimal methane concentration detection range of n deep-sea methane sensors is: C1+C2+...+C nThe optimal methane concentration detection range covers the wide methane concentration range in the deep-sea methane leak region, improving the accuracy of methane concentration detection in deep-sea methane leak regions with unique leak backgrounds. Water flow velocity sensors are also installed to obtain real-time vector flow velocity and directional change data at the detection location. In this embodiment, two water flow velocity sensors are arranged at 90° angles in the same plane to obtain bidirectional water flow velocity data within the plane where the setting point is located. The vector flow velocity at that setting point is then calculated and combined with the methane concentration data to lay the foundation for exploring the correlation between methane eruptions and changes in the submarine flow field in the deep-sea methane leak region. This not only enables adaptive monitoring of methane parameters in the deep-sea methane leak region, but also provides multi-directional, real-time monitoring of flow field changes in the methane seepage region, facilitating the systematic revelation of the correlation and spatial distribution relationship between the submarine current field and the methane concentration gradient diffusion in the deep-sea methane leak region.

[0059] The adaptive monitoring system's test range meets the unique conditions of deep-sea methane leak zones, where methane concentrations are unstable and vary widely. Furthermore, since the deep-sea's low ambient temperature ranges from 3°C to 5°C, the deep-sea methane concentration sensor selected in this embodiment has an operating temperature range of 2°C to 20°C, suitable for this extreme environment. Furthermore, the average water depth of deep-sea methane seepage areas in the South China Sea ranges from 1100 to 1700 meters. The deep-sea methane concentration sensor selected in this embodiment has a maximum pressure-resistant depth of 4000 meters, providing a significant safety margin in terms of pressure resistance. The water velocity sensor selected in this embodiment operates within an ambient temperature range of -2°C to 50°C and a maximum pressure-resistant depth of 6000 meters. This range of sensor parameters also aligns with the required operating environment.

[0060] In specific implementation, when the adaptive monitoring system is used for wide-range and long-period adaptive monitoring of methane parameters in deep-sea methane leakage areas, all deep-sea methane sensors used to measure methane concentrations will simultaneously start methane concentration detection and obtain initial methane concentration data.

[0061] In this embodiment, the controller unit includes: a main control chip module, a storage module, and a calendar module; wherein the main control chip module is used to compare the initial methane concentration data simultaneously acquired by several deep-sea methane sensors with the different optimal methane concentration detection ranges of each deep-sea methane sensor. Within a monitoring cycle, the deep-sea methane sensor whose optimal methane concentration detection range matches the simultaneously acquired initial methane concentration data is turned on, and the deep-sea methane sensor whose optimal methane concentration detection range does not match the simultaneously acquired initial methane concentration data is turned off.

[0062] The storage module is used to store the initial methane concentration data obtained simultaneously by several deep-sea methane sensors and the different optimal methane concentration detection ranges of each deep-sea methane sensor, as well as the water flow velocity data measured by the water flow velocity sensor.

[0063] The calendar module is used to record the monitoring period.

[0064] By comparing the initial methane concentration data obtained simultaneously by multiple deep-sea methane sensors with the optimal methane concentration detection range of each deep-sea methane sensor stored in the main control chip module, on the basis of meeting the effect of accurate measurement in the entire concentration range, the most suitable methane concentration sensor in the current monitoring sequence is selected to be turned on, and the remaining methane concentration sensors are turned off, thereby achieving energy saving, meeting the energy supply stability and durability during short-time sequence and long-cycle operation, and also meeting the needs of wide-range and long-cycle adaptive monitoring of methane parameters in deep-sea methane leakage areas.

[0065] Referring to Figure 1 , the controller unit also includes: a debugging charging interface and a power management module;

[0066] The debugging charging interface is used to pre-set parameters of the controller unit, read data, and charge the energy storage unit. The power management module is used to manage the power supply of the system.

[0067] Specifically, the water flow rate sensor and methane concentration sensor are controlled separately by a main control chip via multiple serial ports. The data measured by the water flow rate sensor and methane concentration sensor are stored in the controller unit's built-in storage module. Storing data in the controller unit's built-in storage module helps ensure the timeliness and stability of data storage. Furthermore, to facilitate the use of the controller unit, a debugging and charging interface is provided. This interface allows for presetting relevant controller unit parameters and reading out measured data. Furthermore, the lithium battery pack can be charged through the debugging and charging interface. The design of this debugging and charging interface ensures the ease of use of the long-term system for monitoring methane parameters in deep-sea methane leak areas proposed in this embodiment.

[0068] In this embodiment, the system further includes: a pressure-resistant chamber, in which the controller unit and the energy storage unit are packaged and integrated. The main structure of the pressure-resistant chamber in this embodiment is a cylindrical body made of titanium alloy. After the controller unit debugs the lithium battery pack according to functional parameters such as working time and working frequency, the lithium battery pack maintains low power consumption operation over a long period of time to meet the energy supply stability and durability of the equipment during short-time and long-cycle operation. At the same time, the controller unit is integrated into the interior of the pressure-resistant chamber. This arrangement not only meets the self-contained design requirements of the system, but also ensures that the system controller circuit board can operate stably under extreme conditions in the deep sea.

[0069] The implementation process of the wide-range, long-period adaptive monitoring system for methane parameters in deep-sea methane leakage areas proposed in this embodiment is further described as follows:

[0070] Multiple deep-sea methane concentration sensors are controlled by the main control chip, and the equipment is debugged for methane concentration detection. Before the test begins, all deep-sea methane concentration sensors remain turned on, and the methane concentration data obtained at the same time is stored in the storage module of the controller unit. The main control chip module calculates the data and classifies it into the optimal methane concentration detection range of Cn, and controls the deep-sea methane concentration sensors that meet the concentration range to remain turned on for a certain time sequence of detection work. The remaining deep-sea methane concentration sensors are turned off to save energy. After the monitoring work under the time sequence is completed, all deep-sea methane concentration sensors are turned off and the monitoring data is recorded; the calendar module in the controller unit records the monitoring cycle and instructs the equipment to turn on in the next monitoring cycle, repeating the above sensor detection and targeted selection of deep-sea methane concentration sensors in the optimal methane concentration detection range. Then, it is fully assembled with the energy storage unit for the next step of long-term underwater monitoring work;

[0071] After the system was launched, an underwater robot was deployed to the test area of ​​the deep-sea methane leak region to initiate monitoring. Due to the high heterogeneity of methane leak systems in deep-sea methane leak regions, a short-time sequence, long-cycle monitoring approach was adopted to ensure the most complete monitoring of methane parameters at each leak stage. The system operated according to onshore commissioning procedures. During each monitoring cycle, the system cycled through a monitoring mode that shifted from fully activating the equipment to selecting the deep-sea methane concentration sensor with the optimal methane concentration detection range after system calculation. This covered a wide range of possible methane concentrations. Before the system was launched, the water velocity sensor was commissioned and calibrated in water with known direction and velocity. After the system was launched, the water velocity sensor remained activated in real time during each monitoring cycle. The acquired data on real-time changes in the seafloor hydraulic flow field was stored in the controller unit's memory module. After the long-term monitoring cycle, the long-cycle adaptive monitoring system was retrieved.

[0072] As shown in Figure 2, in this embodiment, the system is placed around the central leak vent in a deep-sea methane leak zone. The system is positioned in a concentric circle extending outward from the vent, with the system detection port facing the vent. This system, placed around the central leak vent in the deep-sea methane leak zone, combines long-term and short-term monitoring data of methane concentration with data on seafloor flow field changes. This allows for the study of the correlation between changes in methane concentration and seafloor flow field, and for the investigation of the spatial distribution of methane concentration in the deep-sea methane leak zone.

[0073] Example 2 As shown in FIG3 , this example proposes a method for adaptively monitoring methane parameters over a wide range and a long period in a deep-sea methane leakage area. The method is based on the adaptively monitoring methane parameters over a wide range and a long period in a deep-sea methane leakage area described in Example 1 and includes the following steps:

[0074] S1: Set the upper limit of the monitoring cycle number;

[0075] S2: Obtain the methane concentration range of the vent location in the deep-sea methane leakage area;

[0076] S3: Several deep-sea methane sensors for measuring methane concentration simultaneously start methane concentration detection and obtain initial methane concentration data, and start water flow velocity sensors to measure water flow velocity;

[0077] S4: During a monitoring cycle, the initial methane concentration data simultaneously acquired by several deep-sea methane sensors are compared with the different optimal methane concentration detection ranges of each deep-sea methane sensor. The deep-sea methane sensors whose optimal methane concentration detection ranges match the initial methane concentration data are kept turned on to be in a working state and detect the methane concentration; the deep-sea methane sensors whose optimal methane concentration detection ranges do not match the initial methane concentration data are turned off to be in a dormant state.

[0078] S5: Determine whether the number of monitoring cycles reaches the upper limit. If so, output the water flow velocity data detected by the water flow velocity sensor in each monitoring cycle and the methane concentration data detected by the deep-sea methane sensor in working state in each monitoring cycle; otherwise, return to S2.

[0079] In the above process, when obtaining the methane concentration range of the vent position in the test area of ​​the deep-sea methane leakage area, the methane concentration data of the deep-sea methane leakage area involved in previous studies are retrieved to locate the wide-range methane concentration range of the vent position, and then the selected wide-range methane concentration range of the deep-sea methane leakage area is divided into multiple concentration ranges covering the range, and the most suitable methane concentration sensor for the range is selected according to different concentration ranges.

[0080] In this embodiment, three deep-sea methane concentration sensors with different concentration ranges and two water flow velocity sensors placed horizontally in the same plane at 90 degrees are selected. The monitoring cycle of the deep-sea methane sensor is started on land, the optimal methane concentration detection range is selected, and the water flow direction and flow velocity measurement of the water flow velocity sensor are corrected before the system is put into water. During the long-period adaptive monitoring cycle, the two water flow velocity sensors are turned on throughout the entire process to ensure the timeliness of the detection results. The three deep-sea methane concentration sensors work simultaneously when they are just turned on, and measure the methane concentration data of the deep-sea methane leakage area at the same time (for example, the measured methane concentration data is 20umol / L) and feed it back to the controller unit. The controller unit compares the measured results with the optimal methane concentration detection range of the three deep-sea methane concentration sensors. The deep-sea methane concentration sensors that meet the concentration results (for example, the methane sensor with the optimal methane concentration detection range of 500nmol / L-50umol / L) continue to work, while the sensors that do not meet the concentration results (methane sensors with the optimal methane concentration detection range of 20nmol / L-1umol / L and 20umol / L-1000umol / L) are in a dormant state to ensure low power consumption of the system. After completing a monitoring cycle, the controller unit puts the system into hibernation to save energy. When the next monitoring cycle arrives, the system starts up and the deep-sea methane concentration sensor restarts the working cycle of methane concentration detection, comparison, and directional selection of sensors. The water flow velocity sensor remains in working state until it goes into hibernation.

[0081] In addition to the same implementation steps as the method proposed in Example 2, Example 3 combines the long-term and short-term monitoring data of methane concentration in the deep-sea methane leakage area with the hydraulic flow field change data corresponding to the water flow velocity data to further study the correlation between the change in methane concentration and the change in the seabed flow field. As shown in Figure 4, the wide-range, long-term adaptive monitoring method for methane parameters in the deep-sea methane leakage area proposed in this example also includes:

[0082] S6: extracting water flow velocity data detected by the water flow velocity sensor in each monitoring period and methane concentration data detected by the deep-sea methane sensor in working state in each monitoring period;

[0083] S7: Time synchronization and coordinate system alignment of water flow velocity data and methane concentration data;

[0084] S8: Couple the methane concentration data with the water velocity data and perform spatial interpolation to generate a continuous data field within the monitoring range of the deep-sea methane leakage area;

[0085] S9: Correlation analysis based on continuous data fields;

[0086] S10: Perform spatial autocorrelation analysis to determine the spatial distribution between the hydraulic flow field corresponding to the water velocity data and the methane concentration gradient diffusion.

[0087] Specifically, in S7, data pre-processing is performed for time synchronization and coordinate system alignment to ensure that the timestamps of the water velocity data and the methane concentration data are consistent (using a standard time format, such as UTC, to avoid time zone differences), that the water velocity data and the methane concentration data use the same coordinate system, and that the data units are unified (for example, ensuring that the unit of flow velocity is m / s and the unit of methane concentration is ppm). In S8, the methane concentration data obtained by multiple deep-sea methane concentration sensors are coupled with the water velocity data and spatially interpolated. An appropriate interpolation method (such as Kriging interpolation) is selected to generate a continuous data field based on the existing data points within the geographical monitoring range of the entire deep-sea methane leak area. Ensure that the interpolation method does not introduce problems of over-smoothing or over-fluctuation. Then, perform correlation analysis (such as the Pearson correlation coefficient) on the continuous data field generated by the above steps. Use statistical tools to calculate the correlation between water velocity data and methane concentration data to determine whether the correlation is significant, and consider possible lag effects. Finally, perform spatial autocorrelation analysis to determine the spatial pattern between water velocity data and methane concentration gradient diffusion. Use spatial statistical tools, such as Moran's I index, to assess the degree of spatial dependence. Combined with the time scale under long-term monitoring, establish a spatiotemporal model (such as spatiotemporal Kriging or spatiotemporal regression model) to fit and render the spatial distribution of hydraulic flow field and methane concentration gradient diffusion on a long-term scale to obtain the spatial distribution pattern of methane concentration changes in the submarine methane seepage area.

[0088] The embodiments are provided merely to illustrate the present invention and are not intended to limit the embodiments of the present invention. Those skilled in the art will appreciate that other variations or modifications may be made based on the above description. It is not necessary and impossible to enumerate all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention are intended to be included within the scope of protection of the claims.

Claims

1. A wide-range, long-period adaptive monitoring system for methane parameters in deep-sea methane leakage areas, characterized by: The system comprises: A gas and flow field detection unit, comprising a plurality of deep-sea methane sensors for measuring methane concentration and a water flow velocity sensor for measuring water flow velocity in different directions. The plurality of deep-sea methane sensors are arranged in a test area in a deep-sea methane leakage area, and each deep-sea methane sensor has a different optimal methane concentration detection range; The controller unit is used to control the timing of opening and closing detection of each deep-sea methane sensor in each monitoring cycle according to the methane concentration range of the area to be tested and the different optimal methane concentration detection ranges of each deep-sea methane sensor, and is used to control the opening and closing of the water flow velocity sensor, and store the methane concentration data measured by the deep-sea methane sensor and the water flow velocity data measured by the water flow velocity sensor. The energy storage unit is used to provide long-term power supply to the gas and flow field detection unit and the controller unit.

2. The wide-range and long-period adaptive monitoring system for methane parameters in deep-sea methane leakage areas according to claim 1 is characterized in that: The water flow velocity sensors are arranged at 90° in a same plane to obtain bidirectional water flow velocity data in the plane where the setting points are located.

3. The wide-range, long-period adaptive monitoring system for methane parameters in deep-sea methane leakage areas according to claim 1 is characterized in that: Assume that the optimal methane concentration detection ranges of the deep-sea methane sensor used to measure methane concentration are C1, C2, ..., C n , n represents the number of deep-sea methane sensors, and the methane concentration range of the test area is 0 to X, X represents the upper limit of the methane concentration range, and the sum of the optimal methane concentration detection range of n deep-sea methane sensors is: C1+C2+...+C n , covering the methane concentration range of the area to be tested.

4. The wide-range, long-period adaptive monitoring system for methane parameters in deep-sea methane leakage areas according to claim 3 is characterized in that: When the system is used for wide-range and long-period adaptive monitoring of methane parameters in a deep-sea methane leakage area, several deep-sea methane sensors for measuring methane concentration simultaneously start methane concentration detection and simultaneously obtain initial methane concentration data.

5. The wide-range, long-period adaptive monitoring system for methane parameters in deep-sea methane leakage areas according to claim 4 is characterized in that: The controller unit includes: a main control chip module, a storage module, and a calendar module; The main control chip module is used to compare the initial methane concentration data obtained by several deep-sea methane sensors with the different optimal methane concentration detection ranges of each deep-sea methane sensor. For example, within a monitoring period, the deep-sea methane sensor whose optimal methane concentration detection range matches the initial methane concentration data obtained at the same time is turned on, and the deep-sea methane sensor whose optimal methane concentration detection range does not match the initial methane concentration data obtained at the same time is turned off; The storage module is used to store the initial methane concentration data obtained simultaneously by a plurality of deep-sea methane sensors and the different optimal methane concentration detection ranges of each deep-sea methane sensor, and to store the water flow velocity data measured by the water flow velocity sensor; The calendar module is used to record the monitoring period.

6. The wide-range, long-period adaptive monitoring system for methane parameters in deep-sea methane leakage areas according to claim 5 is characterized in that: The controller unit also includes: a debugging charging interface and a power management module; The debugging and charging interface is used to pre-set parameters of the controller unit, read data, and charge the energy storage unit; The power management module is used to manage the power supply status of the system.

7. The wide-range and long-period adaptive monitoring system for methane parameters in a methane leakage area according to claim 1 is characterized in that: The system further includes a pressure-resistant chamber, in which the controller unit and the energy storage unit are packaged and integrated.

8. The wide-range, long-period adaptive monitoring system for methane parameters in deep-sea methane leakage areas according to claim 1 is characterized in that: The system is placed around the central leakage vent of the deep-sea methane leakage area.

9. A method for adaptively monitoring methane parameters over a wide range and over a long period in a deep-sea methane leakage area, characterized in that: The method is implemented based on the wide-range and long-period adaptive monitoring system for methane parameters in deep-sea methane leakage areas according to claim 1. The following steps are involved: S1: Set the upper limit of the monitoring cycle number; S2: Obtain the methane concentration range of the vent location in the deep-sea methane leakage area; S3: Several deep-sea methane sensors for measuring methane concentration simultaneously start methane concentration detection and obtain initial methane concentration data, and start water flow velocity sensors to measure water flow velocity; S4: During a monitoring cycle, the initial methane concentration data simultaneously acquired by several deep-sea methane sensors are compared with the different optimal methane concentration detection ranges of each deep-sea methane sensor. The deep-sea methane sensors whose optimal methane concentration detection ranges match the initial methane concentration data are kept turned on to be in a working state and detect the methane concentration; the deep-sea methane sensors whose optimal methane concentration detection ranges do not match the initial methane concentration data are turned off to be in a dormant state. S5: Determine whether the number of monitoring cycles has reached the upper limit. If so, the output water flow velocity sensor is The water flow velocity data detected during the monitoring period and the methane concentration data detected by the deep-sea methane sensor in working state in each monitoring period; otherwise, return to S2.

10. The method for adaptively monitoring methane parameters over a wide range and for a long period in a deep-sea methane leakage area according to claim 9, characterized in that: The method further comprises: S6: extracting water flow velocity data detected by the water flow velocity sensor in each monitoring period and methane concentration data detected by the deep-sea methane sensor in working state in each monitoring period; S7: Time synchronization and coordinate system alignment of water flow velocity data and methane concentration data; S8: Couple the methane concentration data with the water velocity data and perform spatial interpolation to generate a continuous data field within the monitoring range of the deep-sea methane leakage area; S9: Correlation analysis based on continuous data fields; S10: Perform spatial autocorrelation analysis to determine the spatial distribution between the hydraulic flow field corresponding to the water velocity data and the methane concentration gradient diffusion.

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