Comprehensive prediction method for natural hydrogen accumulation potential area

Abstract

The invention discloses a comprehensive prediction method for a natural hydrogen reservoir-forming potential area. The method comprises the steps of data collection and analysis, natural hydrogen geochemical survey and natural hydrogen geophysical survey. The beneficial effects of the method are that through integration of multi-dimensional data and data such as geology, remote sensing, geochemistry, geophysics and the like, a favorable area and a potential reservoir forming area of natural hydrogen can be revealed by using a comprehensive method. Through the comprehensive data application analysis, the one-sidedness of a single data source is avoided, and the accuracy of judging the natural hydrogen accumulation potential area is greatly improved. And a solid basis is provided for determining natural hydrogen source rocks and migration channels, so that a favorable area in which natural hydrogen exists is locked more accurately.

Description

Technical Field

[0001] The invention relates to a method for predicting a natural hydrogen accumulation potential area, in particular to a comprehensive prediction method for a natural hydrogen accumulation potential area, and belongs to the technical field of energy prediction. Background Art

[0002] Hydrogen has long been considered a clean fuel with high energy density for achieving net zero emissions, which can be used in vehicles, power generation and industrial processes. Hydrogen is usually formed by the oxidation of fossil fuels or the electrolysis of water. In both cases, some methods produce byproducts such as carbon dioxide, while others have high hydrogen production costs. Therefore, the ability to produce and utilize low-cost, cheap and clean hydrogen in the future will play a key role in energy transformation. Considering the current production costs and carbon emission challenges, natural hydrogen produced naturally underground has received widespread attention worldwide, and many countries around the world have begun natural hydrogen exploration and research. Natural hydrogen is a new, clean, low-carbon hydrogen energy produced by geological processes that can migrate and enrich in geological reservoirs.

[0003] The earth continuously produces natural hydrogen through several chemical reactions. The natural hydrogen generated underground may be related to the oxidation of ferrous minerals, radiolysis of water, pyrolysis of organic matter and degassing of the mantle. Although natural hydrogen is widely present in geological environments such as the ocean and continental crust, volcanic gas and hydrothermal systems, and a large amount of it escapes on the surface, natural hydrogen on land for energy purposes has not been mined on an industrial scale. The reason is that there is a lack of a fully effective scientific theory for the formation, migration and enrichment of hydrogen inside the earth, and there is no effective natural hydrogen exploration method. As a result, it is impossible to judge whether the development of natural hydrogen is feasible when the quantity is unknown, and it is impossible to accurately calculate whether natural hydrogen is economically feasible. These restrict the development of natural hydrogen as a new energy source.

[0004] For a long time, people have been influenced by traditional concepts and believe that hydrogen is difficult to exist in large quantities underground or has no exploration value. Due to the limitations of technical equipment and concepts, the current exploration and research of natural hydrogen faces many problems. So far, there has been no example of truly commercial development of natural hydrogen in the world, especially in my country, where there are almost no exploration activities for natural hydrogen. This has resulted in insufficient understanding of the natural hydrogen system and a lack of historical measurement data on natural hydrogen, which makes it difficult to accurately predict its distribution and potential areas for reservoir formation. Solving these problems requires a large amount of natural hydrogen surveys and research to obtain first-hand information. However, how to quickly and accurately select possible natural hydrogen potential areas in the vast land of China has become the key point in finding natural hydrogen reservoirs. However, because natural hydrogen reservoirs have not yet received high attention in the industry, up to now, there has not been a set of technologies and working methods for predicting natural hydrogen potential areas. This is the primary problem facing my country's current natural hydrogen exploration and development. Therefore, a method for predicting natural hydrogen potential areas is invented to solve the above problems. Summary of the invention

[0005] The purpose of the present invention is to provide a comprehensive prediction method for natural hydrogen accumulation potential areas in order to solve at least one of the above technical problems.

[0006] The present invention achieves the above-mentioned purpose through the following technical scheme: A comprehensive prediction method for natural hydrogen accumulation potential areas comprises the following steps:

[0007] Step 1: Data collection and analysis: Collect regional geological, remote sensing, geochemical and geophysical data and data in the prediction area. Based on this, analyze and study the regional structure and source rock distribution characteristics of the study area. Use remote sensing interpretation data to infer the distribution of "fairy circles", infer the landscape anomalies formed on the surface in possible hydrogen escape areas, delineate the scope of potential natural hydrogen systems, and screen out natural hydrogen investigation "blocks";

[0008] Step 2: Natural hydrogen geochemical survey: after comprehensive analysis and research of existing geological data, field natural hydrogen gas geochemical measurements are conducted in the selected natural hydrogen survey "blocks". Natural hydrogen escape areas in the selected natural hydrogen survey "blocks" are detected through natural hydrogen detection in boreholes, gas discharge ports, springs and soil, and high-concentration hydrogen replenishment monitoring;

[0009] Step 3: Geophysical survey of natural hydrogen: Conduct geophysical survey of natural hydrogen in the natural hydrogen escape area delineated by gas geochemical measurements. Through comprehensive anomaly analysis, infer the potential source rocks, migration pathways and caprocks of natural hydrogen. Combined with regional geological characteristics and gas geochemical measurement results, predict the potential for natural hydrogen accumulation.

[0010] As a further solution of the present invention: in step one, a comprehensive analysis of the predicted area is carried out based on the existing regional information and data to screen the natural hydrogen investigation "block", and the collected information includes geological data related to the source of hydrogen, geophysical and geochemical data of the mining area and drilling data, and the collected data includes relevant regional geochemical data, regional geophysical data and gas data on the surface, in water and in wells that can reflect the hydrogen migration channels and potential hydrogen accumulation potential areas; at the same time, regional remote sensing interpretation work is carried out, using various multi-spectral and hyperspectral data to interpret various alteration and landscape anomalies related to natural hydrogen, determine the location of the "fairy circle", and conduct in-depth analysis and research on the collected geophysical and geochemical data and remote sensing interpretation results to determine whether there is a natural hydrogen system and screen the natural hydrogen investigation "block".

[0011] As a further solution of the present invention: in step 1, the regional geology is studied based on the geological map and geological report of the region, and the lithology distribution related to the generation of natural hydrogen is studied. At the same time, the regional structural characteristics and hydrodynamic characteristics are analyzed by using the geological map and regional geophysical data to find the possible distribution of natural hydrogen source rocks and migration channels, so as to infer the favorable areas where natural hydrogen exists;

[0012] The study of the distribution characteristics and sources of natural hydrogen in the study area includes the analysis of existing groundwater gas data, geochemical data in sedimentary basins and gas data in drilling. If the geochemical data contains hydrogen concentration data, it is analyzed whether the hydrogen is from deep sources, biological sources or human factors. In addition, other gas concentration data included can be used as indirect indicators for analysis. Indirect indicators must be in the target area. Indirect indicators include water salinity, methane, radon, as well as carbon dioxide and helium. If the radon gas concentration is high, it indicates that the deep stratum rocks may be rich in uranium and there is active water radiolysis, which may produce natural hydrogen. If deep fluids (usually salt water) related to dissolved gases (such as methane and carbon dioxide) can migrate to the surface through faults, these indicators can be used to find areas where hydrogen escape is not found (if any), or to find indicators supporting natural hydrogen enrichment in a specific area on a larger scale.

[0013] "Fairy circles" refer to depressions formed on the surface due to hydrogen escaping from underground. Around the depressions, the presence of high concentrations of hydrogen leads to abnormal growth of various plants, forming surface structures. Remote sensing data is used to interpret and analyze the surface topography to identify fairy circles, and the equivalent diameter of the fairy circles can be calculated. The relationship between the equivalent diameter and depth is about 1%. The slope of the edge of the "fairy circle" depression is usually less than 3%. The depth, diameter and slope parameters can be used to quickly identify "fairy circles" related to natural hydrogen escape. The location of the "fairy circle" can point to areas where natural hydrogen exists underground, which can serve as an auxiliary method for screening potential areas for early natural hydrogen accumulation.

[0014] As a further solution of the present invention: In step 2, a geochemical survey of natural hydrogen gas is carried out in the screening area. First, a portable hydrogen detector is used to detect the hydrogen concentration in drilling, gas discharge ports, bubbling water and soil. The natural hydrogen replenishment situation of the soil is detected by a gas replenishment meter and a flux box, and finally the natural hydrogen escape area and replenishment situation of the area are obtained.

[0015] As a further solution of the present invention: in step 2, the geochemical measurement of natural hydrogen gas specifically includes:

[0016] In the selected natural hydrogen survey "block", natural hydrogen concentration surveys are conducted in boreholes, gas outlets, bubbling water and soil. A portable hydrogen meter is used to measure hydrogen concentration. Single-point sampling is performed at boreholes, gas outlets and bubbling water to obtain natural hydrogen escape concentration data. Natural hydrogen detection in soil is first carried out in this "block" at the faults and "fairy circles" inferred through comprehensive analysis. Area and profile soil gas measurements are carried out. The measurement grid is determined according to the area of ​​the survey area, following the principle of "small scale first, then large scale, and then dense point detection in key areas";

[0017] Long-term detection of natural hydrogen is used to study the amount of natural hydrogen overflow in the soil, so as to better detect the spatial and temporal changes in natural hydrogen in the soil, and thus determine the amount of natural hydrogen replenishment. That is, high-concentration hydrogen content points found by real-time detection are selected for long-term monitoring of natural hydrogen. The observation method is similar to field soil gas geochemical measurement, and measurements are taken at regular intervals.

[0018] Estimating the gas flux, measuring the hydrogen concentration in the soil and boreholes, and then evaluating the natural hydrogen flux will help quantify the amount of natural hydrogen escaping. For natural hydrogen emissions from gas vents, bubbling water or boreholes, flow meters can be used to measure them. The natural hydrogen flux measurement in the soil obtains the natural hydrogen flux data by measuring the change of natural hydrogen gas over time in a closed chamber on the soil surface.

[0019] As a further solution of the present invention: in step three, in the natural hydrogen escape area, various geophysical techniques such as gravity measurement, magnetic measurement, and magnetotelluric measurement are used to detect the underground structure and the location of the natural hydrogen potential area from different angles; the geophysical methods most relevant to natural hydrogen exploration are arranged in order of priority: 1) gravity measurement; 2) magnetic measurement; 3) magnetotelluric measurement; through comprehensive geophysical analysis, the potential source rocks, migration channels and closure layers of natural hydrogen are determined, and the potential areas for natural hydrogen accumulation are predicted.

[0020] As a further solution of the present invention: gravity measurement measures the change of the earth's gravity field, maps the density change below the surface, delineates the potential natural hydrogen trap layer or the fault zone that may provide the natural hydrogen migration channel; uses the gravity anomaly gradient zone to find the fault, so as to find the potential natural hydrogen migration channel; gravity anomaly analysis is performed on the gravity measurement data, combined with geological data, to determine the potential natural hydrogen reservoir and migration channel;

[0021] Magnetic survey is to investigate the changes in the earth's magnetic field caused by rocks and minerals under the surface, identify areas with potential hydrogen source rocks; find potential natural hydrogen source rocks and help identify these geological features related to hydrogen generation; in the area where gravity measurement is deployed, magnetic anomaly analysis is performed on the magnetic measurement data, and the potential natural hydrogen source rocks are determined by combining gravity data and geological information.

[0022] (3) Magnetotelluric survey is based on the measurement of various components of the alternating natural electromagnetic field on the earth's surface to image the resistivity of the earth's interior. In the potential natural hydrogen source rocks, caprocks and migration channels determined by gravity and magnetic measurements, magnetotelluric measurement profiles are deployed to analyze the obtained resistivity anomalies, determine the channels of deep-source hydrogen-rich fluids and potential natural hydrogen closure layers, and conduct a comprehensive analysis combined with gravity and magnetic anomalies to determine the potential areas for natural hydrogen accumulation.

[0023] The beneficial effects of the present invention are:

[0024] 1. The present invention can reveal the favorable areas and potential reservoirs of natural hydrogen through a comprehensive method by integrating multi-dimensional information and data such as geology, remote sensing, geochemistry and geophysics. This comprehensive data application analysis avoids the one-sidedness of a single data source and greatly improves the accuracy of the judgment of the potential areas for natural hydrogen accumulation. It provides a solid basis for determining the source rocks and migration channels of natural hydrogen, and thus more accurately locks in the favorable areas where natural hydrogen exists;

[0025] 2. The present invention uses a variety of geophysical technologies such as gravity measurement, magnetic measurement, and magnetotelluric measurement to detect underground structures and the location of natural hydrogen potential areas from different angles. These technologies complement each other and can provide all-round insight into underground geological conditions. Gravity measurement can determine potential natural hydrogen traps and migration channels; magnetic measurement can identify potential hydrogen source rock areas; and magnetotelluric measurement indicates the channels and potential traps of deep-source hydrogen-rich fluids. The three complement each other and significantly improve the accuracy of identifying natural hydrogen reservoir potential areas;

[0026] 3. The present invention uses remote sensing data interpretation to determine the location of "fairy circles", providing a unique auxiliary means for screening natural hydrogen reservoir potential areas; "fairy circles" may indicate areas where natural hydrogen exists underground, thereby quickly determining the potential scope of natural hydrogen investigation;

[0027] 4. Conducting geochemical measurements of natural hydrogen gas in boreholes, gas outlets, bubbling water and soil can fully understand the escape of natural hydrogen in different media. Through real-time detection and long-term monitoring, we can obtain the concentration data and replenishment of natural hydrogen, determine the natural hydrogen escape area with replenishment, increase the index of finding potential areas supporting natural hydrogen accumulation, and further improve the accuracy of predicting potential areas of natural hydrogen accumulation. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a flow chart for implementing the method for predicting the potential area for natural hydrogen accumulation of the present invention;

[0029] Figure 2 It is a schematic diagram of the comprehensive analysis method based on existing regional information and data of the present invention;

[0030] Figure 3 A schematic diagram of the natural hydrogen gas geochemical survey method of the present invention;

[0031] Figure 4 This is a schematic diagram of the natural hydrogen geophysical survey method of the present invention. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] Embodiment 1

[0034] like Figures 1 to 4 As shown, a comprehensive prediction method for natural hydrogen accumulation potential areas includes the following steps:

[0035] Step 1: Data collection and analysis: Collect regional geological, remote sensing, geochemical and geophysical data and data in the prediction area. Based on this, analyze and study the regional structure and source rock distribution characteristics of the study area. Use remote sensing interpretation data to infer the distribution of "fairy circles", infer the landscape anomalies formed on the surface in possible hydrogen escape areas, delineate the scope of potential natural hydrogen systems, and screen out natural hydrogen investigation "blocks";

[0036] Step 2: Natural hydrogen geochemical survey: after comprehensive analysis and research of existing geological data, field natural hydrogen gas geochemical measurements are conducted in the selected natural hydrogen survey "blocks". Natural hydrogen escape areas in the selected natural hydrogen survey "blocks" are detected through natural hydrogen detection in boreholes, gas discharge ports, springs and soil, and high-concentration hydrogen replenishment monitoring;

[0037] Step 3: Geophysical survey of natural hydrogen: Conduct geophysical survey of natural hydrogen in the natural hydrogen escape area delineated by gas geochemical measurements. Through comprehensive anomaly analysis, infer the potential source rocks, migration pathways and caprocks of natural hydrogen. Combined with regional geological characteristics and gas geochemical measurement results, predict the potential for natural hydrogen accumulation.

[0038] Embodiment 2

[0039] In addition to all the technical features of the first embodiment, this embodiment also includes:

[0040] In step one, a comprehensive analysis of the predicted area is conducted based on existing regional information and data to screen natural hydrogen investigation "blocks", and the collected information includes geological data related to the source of hydrogen, geophysical and geochemical data of the mining area, and drilling data. The collected data include relevant regional geochemical data that can reflect hydrogen migration channels and potential hydrogen accumulation areas, regional geophysical data, and gas data on the surface, in water, and in wells. At the same time, regional remote sensing interpretation work is carried out, using various multi-spectral and hyperspectral data to interpret various alteration and landscape anomalies related to natural hydrogen, determine the location of the "fairy circle", and conduct in-depth analysis and research on the collected geophysical data and remote sensing interpretation results to determine whether there is a natural hydrogen system and screen natural hydrogen investigation "blocks".

[0041] Furthermore, in step 1, the study of regional geology is based on the geological map and geological report of the region, and the distribution of lithologies related to natural hydrogen generation is studied, as shown in Table 1. At the same time, the regional structural characteristics and hydrodynamic characteristics are analyzed using geological maps and regional geophysical data to find the possible distribution of natural hydrogen source rocks and migration channels, so as to infer the favorable areas for the existence of natural hydrogen;

[0042] Table 1 Reference table for the evaluation of natural hydrogen production by each specific process in each rock type (the natural hydrogen output is judged according to four categories: high, medium, low, negligible or variable)

[0043]

[0044]

[0045] The study of the distribution characteristics and sources of hydrogen in the study area includes the analysis of existing groundwater gas data, geochemical data in sedimentary basins, and gas data in drilling. If the geochemical data contains hydrogen concentration data, it is analyzed whether the hydrogen is from deep sources, biological sources, or human factors. If it does not contain hydrogen concentration data, but only contains other gas concentration data, it can be analyzed as an indirect indicator. The indirect indicators must be in the target area. Indirect indicators include water salinity, methane, radon, as well as carbon dioxide and helium. If the radon gas concentration is high, it indicates that the deep stratum rocks may be rich in uranium and there is active water radiolysis, which may produce natural hydrogen. For example, deep fluids (usually salt water) related to dissolved gases (such as methane and carbon dioxide) can migrate to the surface through faults. Using these indicator data, areas where hydrogen escape has not been found before (if any) can be found, or indicators that support the enrichment of natural hydrogen in a specific area can be found on a larger scale.

[0046] "Fairy circles" refer to depressions formed on the surface when hydrogen escapes from underground. Around the depressions, the presence of high concentrations of hydrogen leads to abnormal growth of various plants, forming surface structures. Remote sensing data is used to interpret and analyze the surface topography to identify "fairy circles" and calculate the equivalent diameter of the fairy circles. The relationship between the equivalent diameter and depth is about 1%. The slope of the edge of the "fairy circle" depression is usually less than 3%. The depth, diameter and slope parameters can be used to quickly identify "fairy circles" related to natural hydrogen escape. The location of the "fairy circle" can point to areas where natural hydrogen exists underground, which can serve as an auxiliary method for screening early potential areas for natural hydrogen accumulation.

[0047] Embodiment 2

[0048] In addition to all the technical features of the first embodiment, this embodiment also includes:

[0049] In step 2, a geochemical survey of natural hydrogen gas is carried out in the screening area. First, a portable hydrogen detector is used to detect the hydrogen concentration in drilling, gas discharge outlets, bubbling water and soil. The natural hydrogen replenishment situation of the soil is detected by gas replenishment measuring instruments and flux boxes, and finally the natural hydrogen escape area and replenishment situation of the area are obtained.

[0050] Furthermore, in step 2, the natural hydrogen gas geochemical measurement specifically includes:

[0051] In the selected natural hydrogen survey "block", the natural hydrogen concentration in boreholes, gas discharge ports, bubbling water and soil is investigated. A portable hydrogen meter is used to measure the hydrogen concentration. Single-point sampling is performed at boreholes, gas discharge ports and bubbling water to obtain natural hydrogen escape concentration data. For natural hydrogen detection in soil, area and profile soil gas measurements are first carried out at the faults and "fairy circles" inferred through comprehensive analysis in this "block". The measurement grid is determined according to the area of ​​the survey area, following the principle of "small scale first, then large scale, and then dense point detection in key areas". 1:200,000 (1 point per square kilometer) and 1:50,000 (4 to 8 points per square kilometer) can be used. If natural hydrogen escape is found at these locations, large-scale area soil natural hydrogen measurement is deployed in this area. 1:25,000 (200×100 meters) or 1:10,000 (100×50 meters) can be used to obtain hydrogen concentration data and hydrogen anomaly maps in key areas.

[0052] Long-term detection of natural hydrogen is used to study the monitoring of soil natural hydrogen overflow, so as to better detect the spatial and temporal changes of soil natural hydrogen, so as to determine the replenishment of natural hydrogen; that is, high-concentration hydrogen content points found by real-time detection are selected for long-term monitoring of natural hydrogen. The observation method is similar to field soil gas geochemical measurement. Measurements are taken at regular intervals, and the measurement intervals can be 1 hour, 2 hours, 5 hours, 24 hours, 5 days, 30 days, etc., to observe the natural hydrogen replenishment within a certain period of time and determine the natural hydrogen replenishment data;

[0053] Estimating the gas flux and measuring the hydrogen concentration in the soil and boreholes, and then evaluating the natural hydrogen flux, will help quantify the amount of natural hydrogen escaping. For natural hydrogen emissions from gas vents, bubbling water or boreholes, flow meters are used to measure them. For natural hydrogen flux measurements in soil, natural hydrogen flux data is obtained by measuring the changes in natural hydrogen gas over time in a closed chamber on the soil surface.

[0054] Embodiment 2

[0055] In addition to all the technical features of the first embodiment, this embodiment also includes:

[0056] In step three, in areas where natural hydrogen escapes, various geophysical techniques such as gravity measurement, magnetic measurement, and magnetotelluric measurement are used to detect underground structures and the location of natural hydrogen potential areas using different methods; the geophysical methods most relevant to natural hydrogen exploration are arranged in order of priority: 1) gravity measurement; 2) magnetic measurement; 3) magnetotelluric measurement; through comprehensive geophysical analysis, the potential source rocks, migration pathways and closure layers of natural hydrogen are determined, and the potential areas for natural hydrogen accumulation are predicted.

[0057] Furthermore, gravity measurements measure changes in the earth's gravity field, map changes in density below the surface, and identify potential natural hydrogen traps or fault zones that may provide natural hydrogen migration channels. Natural hydrogen is stored in ultrabasic rock masses / or formed by serpentinization. Detecting gravity anomalies caused by high-density rock masses can find potential natural hydrogen traps. In addition, using gravity anomaly gradient zones to find faults, potential natural hydrogen migration channels can be found. Deploy 1:50,000 large-scale gravity measurements in the area, conduct gravity anomaly analysis on gravity measurement data, and combine geological data to determine potential natural hydrogen reservoirs and migration channels.

[0058] Magnetic survey is to investigate the changes in the earth's magnetic field caused by rocks and minerals under the surface, and identify areas with potential hydrogen source rocks. For example, serpentine alteration and iron-containing minerals can generate natural hydrogen. This can detect magnetic anomalies caused by large amounts of serpentine and magnetite, find potential natural hydrogen source rocks, and help identify these geological features related to hydrogen generation. In the area where gravity measurements are deployed, 1:50,000 magnetic measurements are deployed, and magnetic anomaly analysis is performed on the magnetic measurement data. Combined with gravity data and geological information, potential natural hydrogen source rocks are determined.

[0059] Magnetotelluric survey is based on the measurement of various components of the alternating natural electromagnetic field on the earth's surface to image the resistivity (or inverse conductivity) of the earth's interior; magnetotelluric survey is used to detect resistivity (conductivity) anomalies in the earth's crust, which can indicate the channels of deep-source hydrogen-rich fluids; magnetotelluric profiles are deployed at potential natural hydrogen source rocks, caprocks and migration channels determined by gravity and magnetic measurements, and the obtained resistivity (or conductivity) anomalies are analyzed to determine the channels of deep-source hydrogen-rich fluids and potential natural hydrogen traps. Combined with gravity and magnetic anomalies, a comprehensive analysis is conducted to determine the potential areas for natural hydrogen accumulation.

[0060] Working principle: Collect regional geological, remote sensing, geochemical and geophysical data in the prediction area, and analyze and study the regional structure and source rock distribution characteristics of the study area based on this data. Use remote sensing interpretation data to infer the distribution of "fairy circles", infer the landscape anomalies formed on the surface in possible hydrogen escape areas, delineate the scope of potential natural hydrogen systems, and screen out natural hydrogen survey "blocks"; after comprehensive analysis and research of existing geological data, conduct field natural hydrogen gas geochemical measurements in the screened natural hydrogen survey "blocks", and screen out natural hydrogen escape areas in the natural hydrogen survey "blocks" through natural hydrogen detection in boreholes, gas discharge ports, springs and soil, and monitoring of high-concentration hydrogen replenishment; conduct natural hydrogen geophysical surveys in natural hydrogen escape areas delineated by gas geochemical measurements, using methods including gravity measurement, magnetic measurement and magnetotelluric measurement, and infer potential source rocks, migration channels and caprocks of natural hydrogen through comprehensive anomaly analysis. Combine regional geological characteristics and gas geochemical measurement results to predict the potential for natural hydrogen accumulation.

[0061] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0062] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A comprehensive prediction method for natural hydrogen accumulation potential areas, characterized by: The following steps are involved: Step 1: Data collection and analysis: Collect regional geological, remote sensing, geochemical and geophysical data and data in the prediction area. Based on this, analyze and study the regional structure and source rock distribution characteristics of the study area. Use remote sensing interpretation data to infer the distribution of "fairy circles", infer the landscape anomalies formed on the surface in possible hydrogen escape areas, delineate the scope of potential natural hydrogen systems, and screen out natural hydrogen investigation "blocks"; Step 2: Natural hydrogen geochemical survey: after comprehensive analysis and research of existing geological data, field natural hydrogen gas geochemical measurements are conducted in the selected natural hydrogen survey "blocks". Natural hydrogen escape areas in the selected natural hydrogen survey "blocks" are detected through natural hydrogen detection in boreholes, gas discharge ports, springs and soil, and high-concentration hydrogen replenishment monitoring; Step 3: Geophysical survey of natural hydrogen: Conduct geophysical survey of natural hydrogen in the natural hydrogen escape area delineated by gas geochemical measurements. Through comprehensive anomaly analysis, infer the potential source rocks, migration pathways and caprocks of natural hydrogen. Combined with regional geological characteristics and gas geochemical measurement results, predict the potential for natural hydrogen accumulation.

2. A comprehensive prediction method for natural hydrogen accumulation potential areas according to claim 1, characterized in that: In the step 1, a comprehensive analysis of the predicted area is conducted based on the existing regional information and data to screen the natural hydrogen investigation "block", and the collected information includes geological data related to the source of hydrogen, geophysical and geochemical data of the mining area and drilling data, and the collected data includes relevant regional geochemical data that can reflect the hydrogen migration channel and potential hydrogen accumulation potential area, regional geophysical data and gas data on the surface, water and drilling; at the same time, regional remote sensing interpretation work is carried out, using various multi-spectral and hyperspectral data to interpret various alteration and landscape anomalies related to natural hydrogen, determine the location of the "fairy circle", and conduct in-depth analysis and research on the collected geophysical data and remote sensing interpretation results to determine whether there is a natural hydrogen system and screen the natural hydrogen investigation "block".

3. A comprehensive prediction method for natural hydrogen accumulation potential areas according to claim 2, characterized in that: In the step 1, the regional geology is studied based on the geological map and geological report of the region, and the lithology distribution related to the generation of natural hydrogen is studied. At the same time, the regional structural characteristics and hydrodynamic characteristics are analyzed using the geological map and regional geophysical data to find the possible distribution of natural hydrogen source rocks and migration channels, so as to infer the favorable areas for the existence of natural hydrogen; The study of the distribution characteristics and sources of natural hydrogen in the study area includes the analysis of existing groundwater gas data, geochemical data in sedimentary basins and gas data in drilling. If the geochemical data contains hydrogen concentration data, it is analyzed whether the hydrogen is from deep sources, biological sources or human factors. In addition, other gas concentration data included can be used as indirect indicators for analysis. Indirect indicators must be in the target area. Indirect indicators include water salinity, methane, radon, as well as carbon dioxide and helium. If the radon gas concentration is high, it indicates that the deep stratum rocks may be rich in uranium and there is active water radiolysis, which may produce natural hydrogen. If deep fluids related to dissolved gases can migrate to the surface through faults, these indicators can be used to find areas where hydrogen has not been found before, or to find indicators supporting the enrichment of natural hydrogen in a specific area on a larger scale. "Fairy circles" refer to depressions formed on the surface when hydrogen escapes from underground. Around the depressions, the presence of high concentrations of hydrogen causes abnormal growth of various plants, forming surface structures. Remote sensing data is used to interpret and analyze the surface topography to identify "fairy circles" and calculate the equivalent diameter of fairy circles. The relationship between the equivalent diameter and depth is about 1%. The slope of the edge of the "fairy circle" depression is usually less than 3%. The depth, diameter and slope parameters can be used to quickly identify "fairy circles" related to natural hydrogen escape. The location of "fairy circles" can point to areas where natural hydrogen exists underground, which can serve as an auxiliary method for screening potential areas for early natural hydrogen accumulation.

4. A comprehensive prediction method for natural hydrogen accumulation potential areas according to claim 1, characterized in that: In the step 2, a geochemical survey of natural hydrogen gas is carried out in the screening area. First, a portable hydrogen detector is used to detect the hydrogen concentration in drilling, gas discharge ports, bubbling water and soil. The natural hydrogen replenishment of the soil is detected by a gas replenishment meter and a flux box, and finally the natural hydrogen escape area and replenishment situation of the area are obtained.

5. The comprehensive prediction method for natural hydrogen accumulation potential areas according to claim 1 is characterized by: In step 2, the natural hydrogen gas geochemical measurement specifically includes: In the selected natural hydrogen survey "block", natural hydrogen concentration surveys are conducted in boreholes, gas outlets, bubbling water and soil. A portable hydrogen meter is used to measure hydrogen concentration. Single-point sampling is performed at boreholes, gas outlets and bubbling water to obtain natural hydrogen escape concentration data. Natural hydrogen detection in soil is first conducted in this "block" through comprehensive analysis of inferred faults and "fairy circles" to carry out area and profile soil gas measurements. The measurement grid is determined according to the area of ​​the survey area, following the principle of "small scale first, then large scale, and then dense point detection in key areas"; Long-term detection of natural hydrogen is used to study the amount of natural hydrogen overflow in the soil, so as to better detect the spatial and temporal changes in natural hydrogen in the soil, and thus determine the amount of natural hydrogen replenishment; that is, high-concentration hydrogen content points discovered by real-time detection are selected for long-term monitoring of natural hydrogen. The observation method is similar to field soil gas geochemical measurement, and measurements are taken at regular intervals. Estimating the gas flux and measuring the hydrogen concentration in the soil and boreholes, and then evaluating the natural hydrogen flux, will help quantify the amount of natural hydrogen escaping. For natural hydrogen emissions from gas vents, bubbling water or boreholes, flow meters are used to measure them. For natural hydrogen flux measurements in soil, natural hydrogen flux data is obtained by measuring the changes in natural hydrogen gas over time in a closed chamber on the soil surface.

6. A comprehensive prediction method for natural hydrogen accumulation potential areas according to claim 1, characterized in that: In the step three, in the natural hydrogen escape area, various geophysical techniques such as gravity measurement, magnetic measurement, and magnetotelluric measurement are used to detect the underground structure and the location of the natural hydrogen potential area from different angles; the geophysical methods most relevant to natural hydrogen exploration are arranged in order of priority: 1) gravity measurement; 2) magnetic measurement; 3) magnetotelluric measurement; through comprehensive geophysical analysis, the potential source rocks, migration channels and closure layers of natural hydrogen are determined, and the potential areas for natural hydrogen accumulation are predicted.

7. A comprehensive prediction method for natural hydrogen accumulation potential areas according to claim 6, characterized in that: The gravity measurement measures the change of the earth's gravity field, maps the density change below the surface, delineates the potential natural hydrogen trap layer or the fault zone that may provide the natural hydrogen migration channel; uses the gravity anomaly gradient zone to find the fault, so as to find the potential natural hydrogen migration channel, and conducts gravity anomaly analysis on the gravity measurement data, combined with geological data, to determine the potential natural hydrogen reservoir and migration channel; Magnetic surveying is the investigation of changes in the Earth's magnetic field caused by subsurface rocks and minerals to identify areas with potential hydrogen source rocks; find potential natural hydrogen source rocks and help identify these geological features related to hydrogen generation; In the area where gravity measurements are deployed, magnetic anomaly analysis is performed on the magnetic measurement data, and potential natural hydrogen source rocks are identified by combining gravity data with geological information. (3) Magnetotelluric survey is based on the measurement of various components of the alternating natural electromagnetic field on the earth's surface, and images the resistivity of the transition zone from the surface to the mantle inside the earth. In the potential natural hydrogen source rocks, caprocks and migration pathways determined by gravity and magnetic measurements, magnetotelluric measurement profiles are deployed to analyze the obtained resistivity anomalies, determine the channels of deep-source hydrogen-rich fluids and potential natural hydrogen traps, and conduct a comprehensive analysis combined with gravity and magnetic anomalies to determine the potential areas for natural hydrogen accumulation.

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