Multi-field coupling natural hydrogen exploration area selection method and electronic equipment

Abstract

The invention provides a multi-field coupling natural hydrogen exploration area selection method and electronic equipment, and relates to the technical field of natural hydrogen exploration. The method comprises the following steps: collecting comprehensive information of a target area; wherein the comprehensive information comprises geological data, gas components and isotope distribution information; wherein the geological data at least comprise underground water data, structure development data and lithology development data; judging the main source type of natural hydrogen in the target area based on the comprehensive information; based on the discriminated main source type and geological data of the natural hydrogen, constructing a three-dimensional geologic body model of the target area by using three-dimensional geological modeling software, and based on gas components and isotope distribution information; and in the three-dimensional geologic body model, loading a double-seepage medium seepage model based on the Darcy law, coupling the dilute substance transfer field and the heat conduction field, performing transient numerical simulation to obtain natural hydrogen concentration distribution data in the target area, and determining a natural hydrogen exploration favorable area according to the natural hydrogen concentration distribution data. According to the invention, the universality and the selection area evaluation efficiency of the natural hydrogen selection area evaluation method can be improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of natural hydrogen exploration, and in particular to a multi-field coupling natural hydrogen exploration selection method and electronic equipment. BACKGROUND

[0002] The development history of human energy utilization is the process of human pursuit of efficient use of energy. Humans in the new era have higher requirements for energy. Unlike traditional fossil energy, cleaner and more efficient energy is the direction of future energy development. Hydrogen energy gradually entered the field of vision because of its clean and absolute zero carbon emission characteristics, and became one of the key energies in the global energy revolution. With the innovation of exploration, theory and method, the underground natural hydrogen that was previously ignored by people has gradually been valued. Different amounts of hydrogen have been found in many countries and regions. Hydrogen leakage with a "fairy ring" structure has been detected, and hydrogen content records have been found in mines, oil and gas wells, and geothermal wells. Most of the discovered natural hydrogen is of inorganic origin, and some studies suggest that the origin of some extremely low content soil hydrogen may be microbial origin, and some is hydrogen formed by thermal decomposition of hydrocarbon source rocks in deep layers.

[0003] The current natural hydrogen selection evaluation method is in the research rising stage. Based on the current natural hydrogen selection evaluation method, it can be summarized into two categories. The first one is to complete the natural hydrogen exploration selection work by weighting the related factors of natural hydrogen, and the second one is to complete the natural hydrogen exploration selection work according to the concentration difference of natural hydrogen test points. The former is not strong in universality, the problem is that the weight determination basis is not clear, and it is subjective. Moreover, the weight of the weight method is fixed, and it lacks flexibility. It needs to adjust the weight relationship for different geological environments, hydrogen source characteristics and other factors, and cannot well adapt to the regional difference characteristics of natural hydrogen exploration. The latter lacks depth of research, and the evaluation is carried out through natural hydrogen anomaly value. For example, the surface natural hydrogen concentration cannot reflect the natural hydrogen concentration in the underground buried structure unit, and the underground natural hydrogen concentration cannot reflect the natural hydrogen migration trend under the fracture channeling system. Therefore, some of the existing natural hydrogen selection evaluation methods have certain limitations and deficiencies in the actual evaluation process, and need to be universalized and programmed. SUMMARY

[0004] The embodiments of the present application provide a multi-field coupling natural hydrogen exploration selection method and electronic equipment to solve the problem of improving the universality and efficiency of the natural hydrogen selection evaluation method.

[0005] In a first aspect, the embodiments of the present application provide a multi-field coupling natural hydrogen exploration selection method, comprising: collect comprehensive information of the target area, wherein the comprehensive information comprises geological data, gas component and isotope distribution information, and the geological data at least comprises groundwater data, structural development data and lithology development data; determine a main source type of natural hydrogen in the target area based on the comprehensive information; construct a three-dimensional geological model of the target area by using a three-dimensional geological modeling software based on the determined main source type of natural hydrogen and the geological data, and define flow boundary, concentration boundary, thermal boundary and mechanical boundary of the three-dimensional geological model based on the gas component and the isotope distribution information; load a double-permeability medium seepage model based on Darcy's law in the three-dimensional geological model, couple a rare substance transfer field and a heat conduction field, and perform transient numerical simulation to obtain natural hydrogen concentration distribution data in the target area, and determine a favorable area for natural hydrogen exploration according to the natural hydrogen concentration distribution data.

[0006] In a possible implementation, determining underground geological information of the target area based on the comprehensive information comprises: determining lithology distribution of the target area based on the geological data; judging a first source type of natural hydrogen in the target area according to the lithology distribution and setting hydrogen source rocks, wherein the setting hydrogen source rocks comprise ophiolite, granite, basalt, uranium deposit and hydrocarbon source rock.

[0007] In a possible implementation, determining underground geological information of the target area based on the comprehensive information further comprises: determining a second source type of natural hydrogen according to gas component and isotope distribution rules; wherein the second source type comprises inorganic and / or organic sources; wherein the inorganic source comprises earth degassing, water-rock reaction, water radiation decomposition and high-temperature decomposition, and the organic source comprises biological action and organic matter pyrolysis.

[0008] In a possible implementation, the three-dimensional geological model of the target area is constructed by using a three-dimensional geological modeling software, comprising: using a built-in geometry tool of the software to draw or import a model file containing geodetic coordinates and actual geological information of each layer to define a porous medium area containing matrix and fractures.

[0009] In a possible implementation, the double-permeability medium seepage model based on Darcy's law comprises: enable double-permeability medium features in a Darcy's law interface to distinguish macro-pore areas and micro-pore areas; The Darcy law-based double-permeability medium seepage model is: ; In the formula, is a seepage velocity vector, is a fluid dynamic viscosity, is a permeability tensor, p is a pressure gradient vector; When the size of the seepage velocity vector is greater than a set value, the large-pore region is determined; and when the size of the seepage velocity vector is less than or equal to the set value, the micro-pore region is determined.

[0010] In a possible implementation, before the transient numerical simulation is performed, the method further includes: According to the geological data, an initial pore pressure, an initial hydrogen concentration distribution and an initial temperature field of the three-dimensional geological body model are determined.

[0011] In a possible implementation, the transient numerical simulation is performed in the three-dimensional geological body model by loading the Darcy law-based double-permeability medium seepage model and coupling a rare substance transfer field and a heat conduction field, and includes: A transient solver is selected, a time step is set, and a porous medium flow field, a rare substance transfer field and a heat conduction field are coupled and solved.

[0012] In a possible implementation, when the multi-physical field coupled solution is performed, a maximum cell size of a free tetrahedron mesh is set, and a top interface where a natural hydrogen gas source is located in the three-dimensional geological body model is mesh-encrypted based on the maximum cell size; In the method, the mesh-encryption of the top interface where the natural hydrogen gas source is located in the three-dimensional geological body model based on the maximum cell size includes: A plurality of layer hydrogen concentration matrices are constructed with time variation as a dimension and with a grid cell center as a reference:

[0013] If the fracture dredging is not considered, a hydrogen concentration in the next unit time is equal to an original concentration plus a concentration diffused by Darcy flow in a unit time of the grid cell , and there is:

[0014] In the formula, , is a seepage velocity vector, is a fluid dynamic viscosity, is a permeability tensor, p is a pressure gradient vector, unit grid area, unit time step.

[0015] In a possible implementation, the determining of the natural hydrogen exploration favorable area according to the natural hydrogen concentration distribution data comprises: According to the spatial gradient of the natural hydrogen concentration, a natural hydrogen enrichment area is determined, and the natural hydrogen enrichment area is determined as the natural hydrogen exploration favorable area.

[0016] In a second aspect, an embodiment of the present application provides an electronic device, comprising a memory and a processor, the memory storing a computer program, and the processor implementing the method in the first aspect or any possible implementation manner of the first aspect when executing the computer program.

[0017] In the embodiment of the present application, first, the target area geological data, gas component and isotope distribution information are collected by the system, which can comprehensively reflect the underground geological structure, fluid and gas source characteristics, and lay a reliable data foundation for subsequent analysis. Then, based on these information, the main source types of natural hydrogen are distinguished, which can effectively identify and focus on the hydrogen source rock that plays a leading role in the study area, thereby excluding the interference of non-main rock stratum. Subsequently, the geological body model is constructed by using the three-dimensional geological modeling software and the multi-physical field boundary is accurately defined, realizing the high-fidelity digital representation of the complex underground space structure and initial conditions. On this basis, the double-permeable medium seepage model based on Darcy's law is loaded, and the transient numerical simulation is carried out by coupling the rare substance transfer field and the heat conduction field, which can dynamically reproduce the spatio-temporal evolution law of natural hydrogen migration and accumulation in porous media. Finally, the exploration favorable area is determined according to the concentration distribution data obtained by simulation, so that the selection and evaluation work is changed from the traditional static qualitative judgment to dynamic quantitative prediction, the objectivity of the evaluation result is improved, and the exploration accuracy of natural hydrogen is improved. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 is an application scenario diagram of the multi-field coupled natural hydrogen exploration selection method provided by an embodiment of the present application; Figure 2 is an implementation flowchart of the multi-field coupled natural hydrogen exploration selection method provided by an embodiment of the present application; Figure 3 is a hydrogen generation layer display schematic diagram according to an embodiment of the present application; Figure 4 is a hydrogen initial distribution concentration schematic diagram according to an embodiment of the present application; Figure 5 is a hydrogen source stratum geological body schematic diagram according to an embodiment of the present application; Figure 6 is Figure 5Schematic diagram of the corresponding upper strata and fault features; Figure 7 yes Figure 6 A schematic diagram of the corresponding concentration gradient distribution. Detailed Implementation

[0019] Currently, comprehensive evaluation methods for favorable areas include the following five: Geological analysis method: This method screens favorable areas based on fundamental geological data such as stratigraphy, structure, and lithology. Its advantages are strong foundational knowledge, low cost, and suitability for preliminary delineation; its disadvantages are reliance on experience-based judgment, high subjectivity, and limited accuracy.

[0020] Geophysical exploration (seismic, gravity, electrical, etc.): Identifies subsurface structures through differences in physical properties. Its advantages include wide coverage, the ability to reveal deep information, and high resolution; its disadvantages include high equipment costs, complex data processing, and a high degree of ambiguity in its solutions.

[0021] Geochemical exploration (soil / water chemical indicators, isotope analysis, etc.): directly detects chemical signals related to the target. Its advantages are high sensitivity and strong indicative power, making it suitable for target area delineation; its disadvantages are susceptibility to surface environmental interference (pollution, climate), high sampling density requirements, and limited coverage.

[0022] Remote sensing technology infers underground conditions through indirect indicators such as surface vegetation and landforms. Its advantages are speed and efficiency, suitability for large-scale (especially remote) assessments, and relatively low cost; its disadvantages are significant susceptibility to weather and vegetation variations, difficulty in interpreting indirect indicators, and limited accuracy.

[0023] Numerical simulation integrates multi-source data for modeling and prediction. Its advantages include quantifying the influence of multiple factors, dynamically simulating the process, and improving scientific rigor; its disadvantages include reliance on high-quality data, complex parameter settings, and the possibility that assumptions may deviate from reality.

[0024] Regarding the evaluation methods for natural hydrogen gas selection, research is currently in its early stages. Existing methods often combine geological analysis with expert-assigned values. The specific steps are as follows: 1. First, collect basic data on regional geology, remote sensing, geochemistry, and geophysics. Use remote sensing interpretation of the Andromeda Galaxy and geothermal anomalies to screen potential areas; 2. Using existing natural hydrogen source identification templates, determine the main sources of natural hydrogen, focusing on the primary sources within the study area; 3. Establish a geometric model of the Darcy flow geological body defined by boundary and initial conditions, including locating the hydrogen source and identifying the system's multiphysics fields, establishing the geological body model, loading the Darcy flow model, and applying load to the model; 5. Finally, conduct a natural hydrogen gas selection evaluation.

[0025] Numerical simulation has strong prediction ability, which provides strong support for hydrogen Darcy flow research. Advanced software such as COMSOL realizes the multi-physical field coupling simulation of hydrogen storage system by combining Darcy law with heat and mass transfer model, and helps to optimize the structure design. Frontier technologies such as dynamic mode decomposition can deeply analyze the turbulent structure and evolution law of hydrogen jet.

[0026] The present application aims to provide a multi-field coupled natural hydrogen exploration selection method by integrating geological analysis method and numerical simulation method. The method deeply analyzes the collected underground lithology characteristic data of the exploration area, determines the hydrogen source rock type and its distribution characteristics in combination with the research results of the present stage natural hydrogen genesis, further considers the influence of underground water on the occurrence of natural hydrogen. On this basis, the main source type of natural hydrogen in the research area is identified, a 3D geological body model is constructed, data modeling is carried out on the main natural hydrogen generation layer, multi-physical field coupling exploration selection evaluation under the natural hydrogen three-dimensional reservoir system is realized, and finally a set of natural hydrogen exploration and development selection evaluation method system is formed.

[0027] The embodiments of the present application will be described in detail below with reference to the drawings.

[0028] Figure 1 The application scene diagram of the multi-field coupled natural hydrogen exploration selection method provided by the embodiments of the present application is shown in FIG. 1. Figure 1 As shown in FIG. 1, the geological data, gas component and isotope distribution information of the target area are collected through different information collection terminals, the above comprehensive information of the target area is sent to the server through the network, the server analyzes the comprehensive information, arranges the collected data, screens out valuable information, determines the underground geological conditions of the target area, and comprehensively analyzes and judges whether the target area meets the natural hydrogen exploration, and determines the natural hydrogen exploration selection area, thereby improving the exploration accuracy.

[0029] Figure 2 The implementation flowchart of the multi-field coupled natural hydrogen exploration selection method provided by the embodiments of the present application is shown in FIG. 2. Figure 2 As shown in FIG. 2, the method comprises the following steps: S201, collecting comprehensive information of a target area; wherein the comprehensive information comprises geological data, gas component and isotope distribution information; wherein the geological data at least comprises underground water data, structure development data and lithology development data.

[0030] The execution subject of each embodiment of the present application can be a server, a processor, a microprocessor or other devices with data processing function. In the actual implementation process, the specific implementation mode of the execution subject can be selected according to the actual needs, and the present embodiment does not make special limitation, as long as it is a device with data processing function.

[0031] The target area is a candidate research area in the early pre-exploration stage of natural hydrogen exploration and development. In the specific implementation process, by setting drilling and logging in the target area, underground water data such as underground water burial depth and underground water runoff direction are obtained.

[0032] The tectonic development data and lithologic development data are obtained by field investigation, instrument detection, indoor analysis and data integration of researchers.

[0033] In addition, soil gas samples are collected in the target area, and optionally, not less than 2 samples per square kilometer, and the gas components of the target area are determined based on multiple soil gas samples. Soil samples are collected in the target area, and soil isotope distribution information is obtained through laboratory detection. Optionally, not less than 3 samples per square kilometer, and the gas components of the target area are determined based on multiple soil gas samples.

[0034] S202, determining the main source type of natural hydrogen in the target area based on the comprehensive information.

[0035] The genesis of natural hydrogen is divided into inorganic genesis and organic genesis. The main hydrogen source rocks are five types of ophiolite, granite, basalt, uranium deposit and hydrocarbon source rock. Combined with the collected data, the main source of natural hydrogen is identified according to the distribution of potential hydrogen generating rocks, and usually not less than 2 main sources.

[0036] In this embodiment, the comprehensive geological data, gas components and isotope distribution information can comprehensively analyze the main source type of natural hydrogen in the target area.

[0037] S203, based on the determined main source type of natural hydrogen and geological data, a three-dimensional geological body model of the target area is constructed by using three-dimensional geological modeling software, and the flow boundary, concentration boundary, thermal boundary and mechanical boundary of the three-dimensional geological body model are defined based on the gas components and isotope distribution information.

[0038] In one possible implementation, the three-dimensional geological modeling software is used to construct the three-dimensional geological body model of the target area, which includes: The built-in geometry tool of the software is used to draw or import a model file containing geodetic coordinates and actual geological information of each layer to define a porous medium area containing matrix and fractures. The clear division of matrix and fractures in the porous medium area conforms to the real structure characteristics of underground rocks, avoiding the errors caused by the single medium assumption in the traditional model.

[0039] In the actual implementation process, the three-dimensional geological modeling software realizes the establishment of digital geological body. Optionally, the three-dimensional geological modeling software in the embodiment of the application is COMSOL Multiphysics three-dimensional geological modeling software.

[0040] In the three-dimensional geological modeling software, a geometry tool is built in, and a corresponding geological model of a target region (such as a coal seam, an aquifer structure, and a porous medium region including a matrix and a fracture) is drawn by a relevant researcher based on geological data, or a file related to a geological model of the target region constructed by an external model is imported. Optionally, the file format of the external model construction includes a STEP, IGES, or the like. The file content includes the geodetic coordinates of the target region and the actual geological information of each layer, which provides an accurate geometric basis for subsequent boundary definition, parameter loading, and numerical simulation, so that the model can truly reflect the underground geological structure of the target region, and the reliability and accuracy of the subsequent simulation results are improved.

[0041] According to the identification of the main rock layer providing hydrogen in the research area, the gas component and isotope distribution information obtained through investigation or actual measurement data are used to define a flow boundary, a concentration boundary, a thermal boundary, and a mechanical boundary.

[0042] S204, in the three-dimensional geological model, a double-porous medium seepage model based on Darcy's law is loaded, and a dilute species transfer field and a heat conduction field are coupled to perform transient numerical simulation to obtain natural hydrogen concentration distribution data in the target region, and to determine a natural hydrogen exploration favorable area according to the natural hydrogen concentration distribution data.

[0043] In the implementation process, a physical field interface is added to the three-dimensional geological modeling software, including: a porous medium flow (Porous Media Flow), a dilute species transfer (Transport of Diluted Species), a solid mechanics (Solid Mechanics), and a heat conduction (Heat Transfer).

[0044] The porous medium flow (Porous Media Flow) selects a Darcy's Law interface to describe the seepage of hydrogen in a porous medium (applicable to a low flow rate scenario). The dilute species transfer (Transport of Diluted Species) enables a Convection and Diffusion module to simulate the hydrogen concentration distribution. The solid mechanics (Solid Mechanics) and the heat conduction (Heat Transfer) add a Linear Elastic Material to couple a stress field and a permeability evolution.

[0045] In the three-dimensional geological body model described above, a double-permeability medium seepage model based on Darcy's law is loaded, and a rare substance transfer field (the Convection and Diffusion module is enabled) and a heat conduction field (the Linear Elastic Material is added) are coupled; a transient solving type is selected, a time step and a total simulation time length (for example, the time step is 100,000 years, and the total simulation time length is 3,000,000 years) are set, a solver is configured as a multi-physics field coupled solver, numerical simulation is performed, and finally natural hydrogen concentration distribution data at different time nodes and different spatial positions in the target region are obtained.

[0046] Finally, the natural hydrogen concentration distribution data obtained through simulation are analyzed, gradient intervals are divided according to the concentration spatial distribution characteristics, and a region with a concentration higher than a set concentration (for example, 0.5 mol / m³) is determined as a natural hydrogen enrichment region, which is a favorable region for natural hydrogen exploration.

[0047] In this embodiment, first, the system collects geological data, gas component and isotope distribution information of the target region, which can comprehensively reflect the underground geological structure, fluid and gas source characteristics, and lays a reliable data foundation for subsequent analysis. Then, based on this information, the main source types of natural hydrogen are distinguished, which can effectively identify and focus on the hydrogen source rock that plays a leading role in the study area, thereby excluding the interference of non-main rock layers. Subsequently, a geological body model is constructed by using a three-dimensional geological modeling software and the boundaries of the multi-physics field are accurately defined, realizing high-fidelity digital representation of the complex underground space structure and initial conditions. On this basis, a double-permeability medium seepage model based on Darcy's law is loaded, and a rare substance transfer field and a heat conduction field are coupled for transient numerical simulation, which can dynamically reproduce the spatio-temporal evolution law of natural hydrogen migration and accumulation in porous media. Finally, the favorable region for exploration is determined according to the concentration distribution data obtained through simulation, so that the selection and evaluation work changes from traditional static qualitative judgment to dynamic quantitative prediction, improves the objectivity of the evaluation results, and improves the exploration accuracy of natural hydrogen.

[0048] In a possible implementation, the underground geological information of the target region is determined based on comprehensive information, including: The lithology distribution of the target region is determined based on the geological data. The first source type of natural hydrogen in the target region is determined according to the lithology distribution and the set hydrogen source rock, wherein the set hydrogen source rock includes serpentinite, granite, basalt, uranium deposit and hydrocarbon source rock.

[0049] The known main hydrogen source rocks currently include five types of serpentinite, granite, basalt, uranium deposit and hydrocarbon source rock. There are mainly four sources of natural hydrogen, mainly including: serpentinization (water-rock reaction), radiation decomposition of water, deep mantle degassing and deep hydrocarbon source rock pyrolysis.

[0050] In the natural hydrogen exploration, the source type of hydrogen is controlled by the underground rock type, and the hydrogen is formed by serpentinization of the ophiolite. The hydrogen can also be formed by the redox reaction between the iron-containing minerals and water, in addition to the igneous rock and iron ore, shallow or deep environment, basalt and banded iron formation (BIF). The potassium-containing minerals in the granite can radiolytic water to form a certain content of hydrogen, and the iron-containing minerals such as biotite in the granite can form hydrogen through water-rock reaction. The hydrogen can also be formed by the radiolysis of water in contact with other radioactive nuclides such as uranium, thorium and potassium. In the specific implementation process, the source of hydrogen can be determined by the preset determination model. When the lithology distribution of the target area includes any one or more of the ophiolite, granite, basalt, uranium deposit and hydrocarbon source rock, the first source type of natural hydrogen can be further determined in combination with the related determination model of water-rock reaction.

[0051] In the specific implementation process, as shown in Figure 3 , the hydrogen generation layer can be displayed in the three-dimensional geological body model according to the first source type of natural hydrogen.

[0052] In the embodiment, the lithology distribution is determined by system analysis of geological data, which provides a precise spatial basis for hydrogen source rock identification. The five types of hydrogen source rocks are screened in a targeted manner, which can quickly exclude the interference of non-main hydrogen source rocks and focus on the lithology types with actual hydrogen generation potential. Through the comprehensive judgment of the development scale and hydrogen generation conditions, the accuracy of the first source type determination is ensured, which provides a clear hydrogen source direction for subsequent model construction and simulation, avoids the deviation of the simulation results caused by the ambiguity of the hydrogen source identification, and improves the pertinence of the entire exploration selection method.

[0053] In the specific implementation process, the source type of natural hydrogen in the same target area environment can be multiple, and the way to determine the source type of natural hydrogen is various in different embodiments.

[0054] In one possible implementation, the underground geological information of the target area is determined based on the comprehensive information, and the method further includes: determining a second source type of natural hydrogen according to the gas component and the isotope distribution rule; wherein the second source type includes an inorganic source and / or an organic source; wherein the inorganic source includes degassing of the earth, water-rock reaction, water radiolysis and high temperature decomposition; and the organic source includes biological action and pyrolysis of organic matter.

[0055] The foregoing embodiment mainly determines the first source type of natural hydrogen based on water-rock reaction through lithology distribution and setting hydrogen source rock. In actual production and life, there are other sources of hydrogen. In actual implementation, according to the collected or tested hydrogen-containing gas components and isotope distribution rules, the main sources of natural hydrogen are determined, such as inorganic genesis mainly including earth degassing, water-rock reaction, water radiation decomposition and high temperature decomposition, or organic genesis mainly including biological action and organic matter pyrolysis.

[0056] Optionally, whether the earth degassing can be determined by whether the inert gas without characteristics is contained in the gas component; whether the water-rock reaction can be determined by whether there is evidence of mineral alteration; whether the water radiation decomposition can be determined by whether there is radionuclide enrichment; whether the high temperature decomposition can be determined by whether the temperature reaches the inorganic high temperature hydrogen generation condition; and whether the organic genesis can be determined by whether there is set organic organism or organic matter.

[0057] In the embodiment, through accurate analysis of the gas component and isotope distribution rules, the rationality of the first source type can be verified from the chemical characteristic level, forming a dual discrimination system of "lithology-chemical characteristics"; the determination of the second source type further refines the hydrogen genesis, avoiding the limitations that may exist in single lithology discrimination. The clear division of organic genesis and inorganic genesis provides a scientific basis for parameter setting in subsequent models, makes the model more in line with the actual hydrogen generation mechanism, and also improves the comprehensiveness and reliability of the source discrimination result, thereby improving the accuracy of the final exploration selection identification.

[0058] In a possible implementation, loading a double-permeable medium percolation model based on Darcy's law includes: In the Darcy's law interface, the double-permeable medium feature is enabled to distinguish the macro-pore area and the micro-pore area.

[0059] In the specific implementation process, the "Darcy's law" interface in the three-dimensional geological modeling software is opened, and the "double-permeable medium" feature is enabled in the setting panel of the interface. According to the lithology characteristics and pore structure analysis results of the target area, the pore area is set. Through the parameter association function of the software, the porosity and permeability of the double-permeable medium are made to correspond to the lithology area in the three-dimensional geological body model one by one, and the loading of the double-permeable medium percolation model is completed.

[0060] In the embodiment, the dual-permeability medium feature is enabled and the macropore and micropore regions are distinguished, which can accurately reflect the influence of the pore structure difference of different lithology regions on the hydrogen seepage, and avoids the defect that a single seepage model cannot distinguish the seepage characteristics of different media. The loading of the dual-permeability medium seepage model makes the hydrogen seepage process simulation in the underground more in line with the actual situation, and can accurately capture the characteristics of the rapid migration of hydrogen in the macropore region and the slow diffusion in the micropore region, providing an accurate seepage mechanics basis for subsequent concentration distribution simulation and improving the scientificity of the simulation results.

[0061] In a possible implementation, before the transient numerical simulation, the method further includes: According to the geological data, the initial pore pressure, the initial hydrogen concentration distribution and the initial temperature field of the three-dimensional geological body model are determined.

[0062] In the actual implementation process, optionally, the pore pressure at different depths or in different rock layers is determined in combination with the rock layer distribution in the geological material and the underground water data, or the pore pressure detection sensor is arranged at different positions in the exploration well to collect the pore pressure.

[0063] Optionally, the hydrogen concentration distribution at different positions is obtained by sampling at different positions, or the hydrogen concentration distribution is determined in combination with the hydrogen generation potential of the hydrogen generation layer.

[0064] Optionally, the temperature values at different positions are obtained by arranging temperature sensors or infrared spectrometers at different positions in the exploration well.

[0065] The pore pressure, the hydrogen concentration and the temperature value are discrete, and in order to reflect the change trend of each item, the initial pore pressure, the initial hydrogen concentration distribution and the initial temperature field are determined by interpolation based on the calculation data of the measured data of the target region.

[0066] After the initial pore pressure, the initial hydrogen concentration distribution and the initial temperature field are determined, the distribution state can be displayed in the three-dimensional geological body model corresponding to the target region by using a three-dimensional geological modeling software. For example, Figure 4 An example of a hydrogen concentration distribution diagram is shown.

[0067] In the embodiment, the initial pore pressure, the initial hydrogen concentration distribution and the initial temperature field are determined based on the measured geological data of the target region and reasonable interpolation calculation, which avoids the deviation of the initial conditions caused by subjective assumptions. The accurate initial conditions provide a reliable starting point for the transient numerical simulation, and ensure that the simulation process can truly reflect the migration, diffusion and aggregation rules of hydrogen in the underground.

[0068] In a possible implementation, in the three-dimensional geological body model, a dual-permeability medium seepage model based on Darcy's law is loaded, and a rare substance transfer field and a heat conduction field are coupled to perform transient numerical simulation, including: The transient solver is selected, the time step is set, and the porous medium flow field, the rare substance transfer field and the heat conduction field are coupled and solved.

[0069] The coupling relationship of the porous medium flow field, the rare substance transfer field and the heat conduction field is established in the software, the seepage velocity of the porous medium flow field is input as the convection term of the rare substance transfer field, and the convection and diffusion process of hydrogen is affected. The temperature distribution of the heat conduction field indirectly acts on the porous medium flow field and the rare substance transfer field by affecting the fluid viscosity and the rock permeability. The multi-physical field coupling solver of the software is enabled, the solving precision is set, and the numerical solution of the coupled control equation is obtained. The natural hydrogen concentration distribution, pressure distribution and temperature distribution data at different time nodes are obtained.

[0070] In this embodiment, the selection of the transient solver and the reasonable setting of the time step can completely simulate the dynamic accumulation process of natural hydrogen on a million-year scale, avoiding the defect that the steady-state simulation cannot reflect the time evolution. The coupling solution of the multi-physical field considers the interaction between seepage, mass transfer and heat transfer, which conforms to the complex physical and chemical process of natural hydrogen accumulation, and is more comprehensive than single physical field simulation. The adaptive time step algorithm and high-precision solution setting improve the calculation efficiency while ensuring the simulation accuracy, and ensure that the simulation results can accurately reflect the spatio-temporal variation law of hydrogen concentration, providing numerical support for the division of favorable areas.

[0071] In a possible implementation, when the multi-physical field coupling solution is performed, the maximum element size of the free tetrahedral mesh is set, and the upper interface where the main source of natural hydrogen in the three-dimensional geological body model is located is meshed based on the maximum element size.

[0072] In this embodiment, the selection of the free tetrahedral mesh can adapt to the complex geometry of the three-dimensional geological body model, ensuring the integrity and rationality of the mesh division. The setting of the maximum element size balances the simulation accuracy and the calculation efficiency. The meshing of the upper interface where the main source of natural hydrogen is located can accurately capture the key process of hydrogen migration from the hydrogen generation layer upward, avoiding parameter mutation caused by too coarse mesh in the key area. The setting of the boundary layer characteristics and the automatic meshing based on the equation further improve the simulation accuracy of the fracture area and the area where the parameters change sharply, reduce the numerical discretization error, and make the results of the multi-physical field coupling solution more consistent with the actual situation, improving the concentration distribution analysis and the accuracy of the favorable area division.

[0073] In a possible implementation, the natural hydrogen exploration favorable area is determined according to the natural hydrogen concentration distribution data, including: According to the spatial gradient of the natural hydrogen concentration, the natural hydrogen enrichment area is determined, and the natural hydrogen enrichment area is determined as the natural hydrogen exploration favorable area.

[0074] Wherein, optionally, the spatial gradient can be set in advance. For example: according to the concentration distribution characteristics, 5 concentration gradient intervals are divided: ≤0.05 mol / m³ (background area), 0.05-0.1 mol / m³ (low concentration area), 0.1-0.3 mol / m³ (medium concentration area), 0.3-0.5 mol / m³ (higher concentration area), >0.5 mol / m³ (high concentration area).

[0075] Optionally, based on the hydrogen concentration distribution of the target area. Due to the different complexity of different areas, the natural hydrogen distribution is different, for example, the area with the lowest hydrogen concentration in the target area is 0.1 mol / m³, and the area with the highest hydrogen concentration reaches 0.8 mol / m³, so the above concentration gradient interval division is not applicable. Therefore, in order to adapt to different exploration needs, based on the hydrogen distribution of the actual research area, that is, the target area, the hydrogen gradient is divided, which can improve the accuracy of determining the favorable area of natural hydrogen exploration.

[0076] In different embodiments, the area with relatively high hydrogen concentration is determined as the natural hydrogen enrichment area based on the spatial gradient of the natural hydrogen concentration, and the natural hydrogen enrichment area is determined as the favorable area of natural hydrogen exploration of the target area.

[0077] In this embodiment, the zoning based on the spatial gradient of the natural hydrogen concentration can directly reflect the aggregation degree and spatial distribution law of hydrogen, avoiding the defects of subjective division of favorable areas in traditional methods. Determining the enrichment area as the favorable area of exploration directly relates the hydrogen resource potential and exploration target, ensuring the resource value of the favorable area. The quantitative analysis of the concentration gradient makes the boundary and range of the favorable area more clear, providing precise spatial guidance for subsequent exploration well site deployment and exploration range determination, and improving the scientificity and operability of the division of the favorable area, making the exploration work more targeted and efficient.

[0078] The above is described from different improvement directions of the three-dimensional geological modeling software, and the execution process of the three-dimensional geological modeling software is described in combination with specific embodiments.

[0079] First, according to the actual data of drilling, logging and geophysical exploration, a three-dimensional geological model reflecting the real underground situation is constructed.

[0080] The model includes the geometric shape, porosity, permeability, temperature field, pressure field and initial distribution of hydrogen of the reservoir; and uses the built-in geometry tool of the simulation tool to draw or import a 3d model (such as coal seam, aquifer structure), defines the porous medium area (matrix, fracture, etc.); the specific operation is to first establish Figure 5 The main hydrogen source stratum geological body is shown, and then Figure 6 The upper stratum and fracture characteristics are established as shown.

[0081] Then, the Darcy's law seepage model is accessed, the "dual permeable medium" feature is enabled, and the macro-pore and micro-pore regions are distinguished.

[0082] Specifically, a preset material (such as hydrogen or water) is selected from a Materials node to automatically load parameters such as density and thermal conductivity; material properties are manually input or defined by a formula, for example, a Darcy flow model that changes with temperature is set. The following steps are included: 1. Single-field settings are performed, including electromagnetism: Electric Potential is applied to the surface of a conductor, and a Scattering Boundary Condition is set at an external boundary; fluid mechanics: Velocity is defined at an inlet, and Pressure is set to zero at an outlet.

[0083] 2. Coupling settings are performed, including thermal-mechanical coupling: a Thermal Expansion module is used to automatically transfer a temperature field to a structural mechanics interface to generate thermal strain; fluid-structure coupling: a Fluid-Structure Interaction interface is enabled, and a No-Slip condition is set for the fluid-solid interface.

[0084] 3. The "dual permeable medium" feature is enabled in the Darcy's law interface to distinguish between macro-pore and micro-pore regions, and is input to form a hydrogen Darcy flow condition that distinguishes between macro-pore and micro-pore regions. In the formula, is a seepage velocity vector, is a fluid dynamic viscosity, is a permeability tensor, and p is a pressure gradient vector.

[0085] In the specific implementation process, when the magnitude of the seepage velocity vector is greater than a set value, it is determined to be a macro-pore region; when the magnitude of the seepage velocity vector is less than or equal to the set value, it is determined to be a micro-pore region. The set value is an expert experience value determined based on the geographical location and environmental conditions of the target region.

[0086] 4. According to the actual geological environment, the initial pore pressure, hydrogen concentration distribution (such as the original hydrogen saturation of a hydrogen anomaly point), and temperature field are set.

[0087] 5. Set the maximum element size, select the Free Tetrahedral mesh under the Mesh node, and refine the mesh at the upper interface where the main source of natural hydrogen is located; add a Boundary Layer feature for natural hydrogen, specify 5-15 mesh layers and set the thickness growth rate (1.2-1.5), and accurately analyze the near-wall flow; activate the Based on Equations option, and the system will automatically refine the high stress or high temperature gradient region according to the PDE solution error.

[0088] Here, let S be the area of ​​a unit grid, and construct a multi-layered hydrogen concentration matrix with time variation as the dimension and the grid cell center as the reference:

[0089] If we disregard breakage and conduction, the hydrogen concentration in the next unit time will be equal to the original concentration. Concentration diffused through Darcy flow within a cell of the Gaben grid Then we have:

[0090] in, The hydrogen concentration per unit time for the next grid cell. T is the unit time step, and S is the grid area.

[0091] right Integrate both sides with respect to time t, and define the integration interval (assuming it is [ ]). ]), for both sides of the equation in the time interval [ , Integral within the inner boundary, i.e.:

[0092] Since μ and k typically do not change with time, they can be extracted from the integral sign:

[0093] Furthermore, because basin simulation software can obtain the reservoir's temperature and pressure paths, fluid charging history, and the evolution of fluid chemical composition throughout its geological history, it can also provide... Physical quantities in geological history. The establishment of "digital cores" in multiphysics finite element software can reflect the true pore distribution and mineral grain contact relationships, clearly defining the migration paths of natural hydrogen, thus clearly defining […]. The cumulative change in hydrogen during the stage.

[0094] When t-t0 approaches 1s, we can obtain , where i is related to the actual depth and mesh division, and n is related to the position of the mesh cell projected on the plane.

[0095] In the actual implementation process, the upper part is a sandstone reservoir with porosity of 18% and permeability of 80 mD, the lower part is a shale hydrogen generation layer with porosity of 5% and permeability of 0.01 mD, and there is an anticline trap structure in the upper part of the selected area. A stable hydrogen source of 1000 tons per million years is set at the bottom of the model. This data is a summary of previous studies on the source of natural hydrogen gas organic thermal evolution. The simulation geological time is set to 3 million years.

[0096] Finally, the simulation results are analyzed, and evaluation maps and data are output.

[0097] Within 80 million years after the start of the simulation, hydrogen gas migrates upward, and free-phase hydrogen gas accumulates in the high point of the trap under the driving of buoyancy, and the gas concentration continuously increases, so that the hydrogen gas concentration simulation is as shown in Figure 7 .

[0098] The embodiment of the application also provides an electronic device, including a memory and a processor, the memory stores a computer program, and the processor realizes the method in the method embodiment when executing the computer program. Exemplarily, the electronic device can be a smart phone, a tablet computer, a notebook computer, a desktop computer, a smart speaker, a smart watch, etc., which is not limited here.

[0099] In the above embodiments, the description of each embodiment has its own emphasis, and the parts not described or recorded in a certain embodiment can be referred to the related description of other embodiments. If there is no special description and no logical conflict, the terms and / or descriptions of different embodiments are consistent and can be mutually referenced. The technical features in different embodiments can be combined to form new embodiments according to their inherent logical relationship.

[0100] The above-described embodiments are only used to illustrate the technical solutions of the present application, rather than limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacements for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should be included in the protection scope of the present application.

Claims

1. A method for multi-field coupled natural hydrogen exploration and selection of a region, characterized in that, The method comprises the following steps: collecting comprehensive information of a target area; wherein the comprehensive information comprises geological data, gas component and isotope distribution information; wherein the geological data at least comprises groundwater data, structural development data, lithology development data; determining a main source type of natural hydrogen in the target area based on the comprehensive information; constructing a three-dimensional geological model of the target area by using a three-dimensional geological modeling software based on the main source type of natural hydrogen and the geological data, and defining flow boundaries, concentration boundaries, thermal boundaries and mechanical boundaries of the three-dimensional geological model based on the gas component and isotope distribution information; loading a double-permeability medium seepage model based on Darcy's law in the three-dimensional geological model, coupling a rare substance transfer field and a heat conduction field, and performing transient numerical simulation to obtain natural hydrogen concentration distribution data in the target area, and determining a favorable area for natural hydrogen exploration according to the natural hydrogen concentration distribution data.

2. The method of claim 1, wherein, determining underground geological information of the target area based on the comprehensive information, comprising: determining lithology distribution of the target area based on the geological data; judging a first source type of natural hydrogen in the target area according to the lithology distribution and setting hydrogen source rocks; wherein the setting hydrogen source rocks comprise ophiolite, granite, basalt, uranium deposit and hydrocarbon source rock.

3. The method of claim 2, wherein, determining underground geological information of the target area based on the comprehensive information, further comprising: determining a second source type of natural hydrogen according to gas component and isotope distribution rules; wherein the second source type comprises inorganic and / or organic sources; wherein the inorganic source comprises earth degassing, water-rock reaction, water radiation decomposition and high-temperature decomposition; and the organic source comprises biological action and organic matter pyrolysis.

4. The method of claim 1, wherein, constructing a three-dimensional geological model of the target area by using a three-dimensional geological modeling software, comprising: using a built-in geometry tool of the software to draw or import a model file containing geodetic coordinates and actual geological information of each layer to define a porous medium area containing matrix and fractures.

5. The method of claim 1, wherein, loading a double-permeability medium seepage model based on Darcy's law, comprising: enabling double-permeability medium features in the Darcy's law interface to distinguish between macro-pore areas and micro-pore areas; wherein the double-permeability medium seepage model based on Darcy's law is: ； wherein is the seepage velocity vector, is the fluid dynamic viscosity, is the permeability tensor, p is the pressure gradient vector; when the size of the seepage velocity vector is greater than a set value, it is determined as a macro-pore area; and when the size of the seepage velocity vector is less than or equal to a set value, it is determined as a micro-pore area.

6. The method of claim 1, wherein, before performing transient numerical simulation, further comprising: determining initial pore pressure, initial hydrogen concentration distribution and initial temperature field of the three-dimensional geological model according to the geological data.

7. The method of claim 1, wherein, loading a double-permeability medium seepage model based on Darcy's law in the three-dimensional geological model, coupling a rare substance transfer field and a heat conduction field, and performing transient numerical simulation, comprising: selecting a transient solver, setting a time step, coupling a porous medium flow field, a rare substance transfer field and a heat conduction field, and performing multi-physical field solving.

8. The method of claim 7, wherein, When the multi-physical field coupling solving is performed, a maximum element size of a free tetrahedron mesh is set, and an upper interface where a main source of natural hydrogen in the three-dimensional geological body model is located is mesh-encrypted based on the maximum element size; The mesh-encryption of the upper interface where the main source of natural hydrogen in the three-dimensional geological body model is located based on the maximum element size comprises: A plurality of layer hydrogen concentration matrices are constructed with time variation as a dimension and with grid element centers as a reference: If no fracture flow is considered, the hydrogen concentration in the next time unit is equal to the original concentration The concentration diffused by Darcy flow in the grid cell unit time Then, wherein, , is the seepage velocity vector, is the fluid dynamic viscosity, is the permeability tensor, p is the pressure gradient vector, is the unit grid area, is the unit time step.

9. The method of claim 1, wherein, The determination of the natural hydrogen exploration favorable area according to the natural hydrogen concentration distribution data comprises: According to a spatial gradient of the natural hydrogen concentration, a natural hydrogen enrichment area is determined, and the natural hydrogen enrichment area is determined as the natural hydrogen exploration favorable area.

10. An electronic device, comprising: The device comprises a memory and a processor, the memory stores a computer program, and the processor implements the method according to any one of claims 1 to 9 when executing the computer program.

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