Geothermal resource surface geochemical exploration method and system

Abstract

The invention provides a geothermal resource surface geochemical exploration method and system, and the method comprises the steps: determining a matched net degree according to an exploration area range, collecting gas in soil and soil samples, and determining the gas components and element compositions of the samples through different devices; the influence of the formation reaction is considered, and gas and elements with the migration capacity and anti-interference performance meeting the requirements are selected as geothermal chemical exploration indexes of different formation types; the content of soluble inorganic salt in the stratum and the content of gas in the stratum are measured, and the position where heat storage exists is recognized in combination with the set high-salt and low-gas area; and calculating a cover layer score and a reservoir layer score based on geothermal chemical exploration indexes, further calculating a comprehensive score, and realizing quantitative rating of the thermal reservoir stratum according to the comprehensive score. By adopting the scheme, the problems of insufficient comprehensiveness and insufficient exploration precision in the prior art are solved, the optimization of reliable indexes is realized, a heat storage and cover layer comprehensive evaluation method system is formed based on a heat storage mode of high salt and low gas, and underlying stratum geothermal resources can be effectively tracked.

Description

Technical Field

[0001] The present invention relates to the technical field of chemical exploration of geothermal resources, and in particular to a method and system for surface geochemical exploration of geothermal resources, which implements surface geochemical exploration based on gases and elements for geothermal resources. Background Art

[0002] Geothermal resources are generally concentrated along the edges of tectonic plates, with heat sources mainly from deep earth conduction and heat from radioactive substances in the crust. Changes in temperature factors control the concentration changes of three media: water, inorganic salts in surrounding rocks, and gases. The formation of geothermal resources is accompanied by the enrichment and dilution effects of related substances. Therefore, geochemical exploration technology tracks the enrichment and dilution effects of related substances by sampling and analyzing their concentrations; this type of technology can play an important role in geothermal exploration. Due to the existence of the mantle, it can be said that all underground is geothermal resources, but from the perspective of development benefits, the goal of geothermal exploration projects is to find geothermal resources with shallow burial depths. The shallower the burial depth, the more obvious the surface geochemical characteristics of geothermal resources.

[0003] In the existing geothermal resource surface geochemical exploration technology, gas, element, and microbial geochemical exploration technology are generally used. Gas geochemical exploration technology includes CH4, H2, He, CO2, H2S, soil gas Rn, soil gas Hg, etc.; element geochemical exploration technology includes As, Sb, Bi, B, Li, Rb, Cs, Be, Sn, Pb, Zn, Mn, etc.; microbial geochemical exploration technology, for example, patent document CN 110760573 A proposes a geothermal microbial exploration method, including: soil community microbial information analysis of soil samples in known geothermal areas and background areas, determining geothermal sensitive bacteria and their thresholds; collecting soil samples in the area to be explored and detecting and analyzing whether there are geothermal sensitive bacteria and / or the relative abundance of geothermal sensitive bacteria. When there are geothermal sensitive bacteria and / or the relative abundance of geothermal sensitive bacteria in the soil samples of the area to be explored is above the threshold, the area to be explored is judged to be a geothermal field.

[0004] The factors considered in existing technologies are not comprehensive enough. There is no theoretical system for surface geochemical exploration, no unified surface geochemical anomaly model, no surface geochemical exploration technology system, and no quantitative evaluation method for surface geochemical anomalies. The exploration application effect needs to be improved. It is necessary to provide a more scientific and comprehensive surface geochemical exploration method for geothermal resources.

[0005] The information disclosed in the background technology section of the present invention is only intended to deepen the understanding of the general background technology of the present invention, and should not be regarded as acknowledging or suggesting in any form that the information constitutes the prior art known to those skilled in the art. Summary of the invention

[0006] In order to solve the above problems and effectively track and accurately predict geothermal resources in the underlying strata, the present invention provides a method for surface geochemical exploration of geothermal resources. In one embodiment, the method comprises:

[0007] Sample collection steps: Determine the matching sampling grid according to the required exploration area, and then implement the collection operation to obtain samples according to the set sampling rules;

[0008] Analysis and measurement steps: for different types of samples, different equipment is used to measure the gas components and elements contained in the samples according to the preset sample measurement list; the sample measurement list contains the gas components and elements to be measured corresponding to different sample types and the matching measurement equipment;

[0009] Index optimization steps: Considering the influence of formation reaction, gas components and elements that meet the requirements of migration capacity and anti-interference are selected from the determination as geothermal chemical exploration indicators for different formation types;

[0010] Thermal reservoir identification steps: Determine the content of soluble inorganic salts and gas in the formation, and identify the location and type of thermal reservoirs based on the set high salt and low gas areas;

[0011] Thermal reservoir evaluation steps: For strata with thermal reservoirs, the cap rock score and reservoir score are calculated based on their geothermal chemical exploration indicators, and then the comprehensive score is calculated and used to achieve quantitative rating of thermal reservoir strata, combined with the corresponding thermal reservoir type output.

[0012] Preferably, in some embodiments of the present invention, in the sample collection step, the sampling rules are set to include sample types and sampling methods, and the sampling methods are set corresponding to the sample types. The sample types include soil samples, soil gas samples and water samples. The soil samples and soil gas samples are collected by drilling to a set depth range using matching tools.

[0013] Further, in some embodiments of the present invention, for soil samples, the measuring equipment in the sample measuring list includes an X-ray fluorescence spectrometer, an inductively coupled plasma mass spectrometer, an emission spectrometer, a mercury analyzer, an atomic fluorescence spectrometer, a polarograph, and an ion selective electrode;

[0014] For soil gas samples, the measurement equipment in the sample measurement list includes a gas chromatograph with a hydrogen flame detector, a gas chromatograph with a thermal conductivity detector, and an isotope mass spectrometer;

[0015] For water samples, the measurement equipment in the sample measurement list includes inductively coupled plasma mass spectrometer and inductively coupled plasma spectrometer.

[0016] Optionally, in some embodiments of the present invention, in the index optimization step, by measuring the sample helium R(3 He / 4 He) and atmospheric helium Ra ( 3 He / 4 When the isotope ratio meets the set mantle source standard, He is preferably used as a geothermal chemical exploration indicator.

[0017] Furthermore, by measuring the carbon isotope of CH4 in the sample: δ 13 C CH4，PDB (‰), when it meets the set indicators, CH4 is preferred as the geothermal chemical exploration indicator;

[0018] Determine the sample CO2 carbon isotope: δ 13 C CO2，PDB (‰) When it meets the set inorganic origin criteria, CO2 is preferred as a geothermal chemical exploration indicator.

[0019] In some embodiments of the present invention, in the index optimization step, if the distribution degree of granite in the current formation reaches the set requirements, He and Rn are not selected as geothermal chemical exploration indicators;

[0020] If the minerals in the current stratum can undergo water-rock reaction to generate H2, H2 should not be selected as a geothermal chemical exploration indicator.

[0021] If the current stratum belongs to the effective farmland area or the time of agricultural withdrawal is within the set time period, N, P and K elements are not selected as geothermal chemical exploration indicators;

[0022] If the current stratum belongs to the seawater intrusion area or saline-alkali area, do not select K, Na, Ca, Mg, Cl, Br, and S elements;

[0023] If the current stratum belongs to a rich mineral area, elements whose content in the minerals reaches the set conditions will not be selected.

[0024] In some embodiments of the present invention, in the heat reservoir identification step, a location where a high-salt area and a low-gas area exist at the same time and the "high-salt" area and the "low-gas" area overlap is identified, and the location where the heat reservoir exists in the underlying stratum is determined; the high-salt area is set to have an inorganic salt content greater than or equal to the mean of the exploration area plus n times the standard deviation (n>0); the low-gas area is set to have a gas content less than or equal to the mean of the exploration area minus n times the standard deviation (n>0);

[0025] Furthermore, in a preferred embodiment, the heat storage identification step includes:

[0026] Heat transfer channel identification steps: determine the content of elemental mercury and combined mercury in the formation, and identify the location of the heat transfer channel, heat-controlling fractures, and heat transfer direction by setting high-value bands of elemental mercury and combined mercury;

[0027] Water transmission channel identification steps: determine the Na, K, and Ca contents in the formation, and identify the location of the water transmission channel, water supply fracture, and water transmission direction in combination with the set Na, K, and Ca high value bands;

[0028] Steps for identifying the location of hot dry rocks: Determine the content of Nb, W, Mo, U, and Th in the formation, and identify the location of hot dry rocks by setting the high-value areas of Nb, W, Mo, U, and Th;

[0029] Steps for identifying the type of thermal reservoir: if there are high-salinity and low-gas areas, heat transfer channels, and water transfer channels at the same time, the thermal reservoir is identified as a hydrothermal type thermal reservoir; if there are high-salinity and low-gas areas, heat transfer channels, and areas with high values ​​of Nb, W, Mo, U, and Th, the thermal reservoir is identified as a hot dry rock type thermal reservoir; if there are high-salinity and low-gas areas, heat transfer channels, water transfer channels, and areas with high values ​​of Nb, W, Mo, U, and Th, the thermal reservoir is identified as a combined hydrothermal-hot dry rock type thermal reservoir.

[0030] Among them, in some embodiments, in the heat transfer channel identification step, the high-value band of each indicator of elemental Hg and combined Hg is the location of the heat transfer channel, and the judgment standard of this band is set to that the indicator content is greater than or equal to the mean value of the exploration area plus n times the standard deviation. It starts from the fracture and ends at the heat reservoir. The combined maximum value of elemental Hg and combined Hg is the heat-controlling fracture position, and the heat transfer direction is from the heat-controlling fracture to the heat reservoir.

[0031] Additionally, in a preferred embodiment, in the water transmission channel identification step, there is a high-value band of Na, K, and Ca indicators as the location of the water transmission channel, and the identification standard of this band is set to the indicator content being greater than or equal to the mean of the exploration area plus n times the standard deviation. It starts from the fracture and ends at the heat reservoir, and the combined highest value of the Na, K, and Ca indicators is the water supply fracture location, and the water transmission direction is from the water supply fracture to the heat reservoir.

[0032] Optionally, in some embodiments, in the step of identifying the location of hot dry rocks, if there are high-value bands of each indicator Nb, W, Mo, U, and Th, the identification standard of the band is set to that the indicator content is greater than or equal to the mean of the exploration area plus n times the standard deviation, and the high-value band area is located within or within a set range near the overlapping area of ​​high salt and low gas, then the area is identified as a hot dry rock distribution area; the identification mode of hot dry rocks is "high niobium, high tungsten, high molybdenum, high uranium, and high thorium".

[0033] Further, in one embodiment, in the thermal reservoir evaluation step, the cap rock score of the formation is calculated according to the following formula:

[0034]

[0035] The reservoir score of a formation is calculated as follows:

[0036]

[0037] Then calculate the comprehensive score: D = D 盖 +D 储 ,

[0038] Where D 盖 Score for the cap layer, G i is the content of gas component, is the regional mean of gas component content; D 储 is the reservoir score, C i is the content of inorganic salt elements, is the regional mean of inorganic salt element content, and D is the comprehensive score.

[0039] Furthermore, in some embodiments of the present invention, in the thermal reservoir evaluation step, the comprehensive scores corresponding to multiple indicators are summed and then divided by the number of indicators used to obtain an average comprehensive score, which represents the percentage of the influence of the thermal reservoir on the gas dilution effect and the element enrichment effect, and the thermal reservoir temperature level is determined based on its value and the set associated evaluation rules.

[0040] Based on the application aspects of the method described in any one or more of the above embodiments, the present invention also provides a geothermal resource surface geochemical exploration system, which executes the method described in any one or more of the above embodiments.

[0041] Compared with the closest prior art, the present invention also has the following beneficial effects:

[0042] The present invention provides a method and system for geochemical exploration of geothermal resources on the ground. The scheme determines a matching grid size according to the scope of the exploration area to collect samples, and different equipment is used to determine the elements of different samples. The sample collection operation is carried out using a grid size dynamically matched with the scope of the exploration area, thereby improving the collection efficiency without affecting the accuracy of sample collection.

[0043] Then, considering the influence of formation reaction, gas components and elements with migration capacity and anti-interference performance that meet the requirements are selected from the determined elements as geothermal chemical exploration indicators for different formation types; in the process of index optimization, the influence of formation reaction and the characteristics of thermal reservoir formation are comprehensively considered to fundamentally avoid the interference of gas components and elements generated by formation reaction, and effectively select geochemical indicators with high correlation with thermal reservoir, strong migration capacity and good anti-interference performance;

[0044] Determine the migration content of soluble inorganic salts and the content of gas in the formation, and identify the location of heat reservoirs in combination with the set salt high and gas low indicators; determine the content of elemental Hg and combined Hg in the formation, and identify the location of heat transfer channels, heat-controlling fractures, and heat transfer directions in combination with the set elemental Hg and combined Hg high-value bands; determine the content of Na, K, and Ca in the formation, and identify the location of water transfer channels, water supply fractures, and water transfer directions in combination with the set Na, K, and Ca high-value bands; determine the content of Nb, W, Mo, U, and Th in the formation, and identify the location of water transfer channels, water supply fractures, and water transfer directions in combination with the set N b. The location of hot dry rocks is identified in areas with high values ​​of W, Mo, U, and Th; the type of thermal reservoir is then identified; the cap rock score and reservoir score are further calculated based on the geothermal chemical exploration indicators, and then the comprehensive score is calculated and quantitative rating of thermal reservoir strata is achieved based on it; based on the thermal reservoir model of "high salt and low gas", a comprehensive evaluation method for thermal reservoirs and cap rocks is formed, and a quantitative evaluation method for surface geochemical anomalies and a geothermal resource prediction method are established, which can effectively track, predict and evaluate geothermal resources in the underlying strata, and improve the exploration and application effect of existing technologies.

[0045] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures particularly pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0047] Figure 1 It is a schematic flow chart of a method for surface geochemical exploration of geothermal resources provided by one embodiment of the present invention;

[0048] Figure 2 The Fe, Ti, V, Cr, C2H6, C2H6, C 2+ , Example of H2 indicator concentration contour map;

[0049] Figure 3 This is an example of a concentration contour map of elemental Hg and combined Hg indicators in implementation case 1 of the surface geochemical exploration method for geothermal resources provided in one embodiment of the present invention;

[0050] Figure 4 This is an example of a Na, K, and Ca indicator concentration contour map of implementation case 1 in a geothermal resource surface geochemical exploration method provided in another embodiment of the present invention;

[0051] Figure 5This is an example of a contour map of the concentrations of Nb, W, Mo, U, Th, and Rn indicators in implementation case 1 of the surface geochemical exploration method for geothermal resources provided in an embodiment of the present invention;

[0052] Figure 6 The Fe, Ti, V, Cr, C2H6, C2H6, C 2+ , Example of H2 indicator concentration contour map;

[0053] Figure 7 This is an example of a contour map of elemental Hg and combined Hg index concentrations in implementation case 2 of a method for geothermal resource surface geochemical exploration provided in an embodiment of the present invention;

[0054] Figure 8 This is an example of a Na, K, and Ca indicator concentration contour map of implementation case 2 in a geothermal resource surface geochemical exploration method provided in another embodiment of the present invention;

[0055] Fig. 9 This is an example of a contour map of Nb, W, Mo, U, Th, and Rn indicator concentrations in implementation case 2 of the geothermal resource surface geochemical exploration method provided in an embodiment of the present invention;

[0056] Fig.10 It is a schematic structural diagram of a surface geochemical exploration system for geothermal resources provided by another embodiment of the present invention. DETAILED DESCRIPTION

[0057] The following will describe the implementation methods of the present invention in detail in conjunction with the accompanying drawings and embodiments, so that the implementers of the present invention can fully understand how the present invention applies technical means to solve technical problems and achieve the implementation process of technical effects and implement the present invention specifically according to the above implementation process. It should be noted that as long as there is no conflict, the various embodiments and various features of the embodiments in the present invention can be combined with each other, and the technical solutions formed are all within the protection scope of the present invention.

[0058] Although the flowcharts describe the operations as sequential processes, many of the operations may be performed in parallel, concurrently, or simultaneously. The order of the operations may be rearranged. A process may be terminated when its operations are completed, but may also have additional steps not included in the accompanying drawings. A process may correspond to a method, function, procedure, subroutine, subprogram, etc.

[0059] Computer devices include user devices and network devices. Among them, user devices or clients include but are not limited to computers, smart phones, PDAs, etc.; network devices include but are not limited to a single network server, a server group consisting of multiple network servers, or a cloud composed of a large number of computers or network servers based on cloud computing. Computer devices can be operated alone to implement the present invention, or they can be connected to the network and implement the present invention through interactive operations with other computer devices in the network. The network where the computer device is located includes but is not limited to the Internet, wide area network, metropolitan area network, local area network, VPN network, etc.

[0060] The terms "first", "second", etc. may be used herein to describe various units, but these units should not be limited by these terms, and these terms are used only to distinguish one unit from another unit. The term "and / or" used herein includes any and all combinations of one or more of the listed associated items. When a unit is referred to as being "connected" or "coupled" to another unit, it can be directly connected or coupled to the other unit, or there can be intermediate units.

[0061] The terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments. Unless the context clearly indicates otherwise, the singular forms "one", "one" and "item" used herein are also intended to include plural numbers. It should also be understood that the terms "include" and / or "comprise" used herein specify the existence of stated features, integers, steps, operations, units and / or components, without excluding the existence or addition of one or more other features, integers, steps, operations, units, components and / or combinations thereof.

[0062] In the field of geothermal resource research, the heat sources are mainly the heat from deep earth conduction and the heat from radioactive substances in the earth's crust. Geochemical exploration technology tracks the enrichment and dilution effects of related substances by sampling and analyzing their concentrations; this type of technology can play an important role in geothermal exploration. Due to the existence of the mantle, it can be said that all underground is geothermal resources, but from the perspective of development benefits, the goal of geothermal exploration projects is to find geothermal resources with shallow burial depths. The shallower the burial depth, the more obvious the surface geochemical characteristics of geothermal resources.

[0063] In the existing geothermal resource surface geochemical exploration technology, gas, element, and microbial geochemical exploration technology are generally used. Gas geochemical exploration technology includes CH4, H2, He, CO2, H2S, soil gas Rn, soil gas Hg, etc.; element geochemical exploration technology includes As, Sb, Bi, B, Li, Rb, Cs, Be, Sn, Pb, Zn, Mn, etc.; microbial geochemical exploration technology, for example, patent document CN 110760573 A proposes a geothermal microbial exploration method, including: soil community microbial information analysis of soil samples in known geothermal areas and background areas, determining geothermal sensitive bacteria and their thresholds; collecting soil samples in the area to be explored and detecting and analyzing whether there are geothermal sensitive bacteria and / or the relative abundance of geothermal sensitive bacteria. When there are geothermal sensitive bacteria and / or the relative abundance of geothermal sensitive bacteria in the soil samples of the area to be explored is above the threshold, the area to be explored is judged to be a geothermal field. The factors considered in existing technologies are not comprehensive enough. There is no theoretical system for surface geochemical exploration, no unified model for surface geochemical anomalies, no technical system for surface geochemical exploration, and no quantitative evaluation method for surface geochemical anomalies. The exploration application effect needs to be improved. How to form a theoretical system for surface geochemical exploration, establish a unified model for surface geochemical anomalies, establish a technical system for surface geochemical exploration, and establish a quantitative evaluation method for surface geochemical anomalies are urgent issues to be solved. It is necessary to provide a more scientific and comprehensive method for surface geochemical exploration of geothermal resources.

[0064] To solve the above problems, the present invention provides a method for surface geochemical exploration of geothermal resources. Based on the surface geochemical exploration theory of "salt dissolving and gas coming out" of thermal reservoirs, a surface geochemical anomaly model of "high salt and low gas" is established. At the same time, geochemical anomaly models of heat-controlling faults, heat transfer channels, heat transfer directions, water supply faults, water transfer channels, water transfer directions, and thermal reservoir types are established. A technical method for surface geochemical exploration of thermal reservoirs and a technical system for evaluating effective caprocks are formed. A quantitative evaluation method for surface geochemical anomalies and a method for predicting geothermal resources are also established, which can effectively track, predict and evaluate geothermal resources in underlying strata.

[0065] Next, the detailed process of the method of the embodiment of the present invention is described in detail based on the accompanying drawings. The steps shown in the flowchart of the accompanying drawings can be executed in a computer system including a set of computer executable instructions. Although the logical order of each step is shown in the flowchart, in some cases, the steps shown or described can be executed in a different order than here.

[0066] Embodiment 1

[0067] Figure 1 The schematic diagram of the process of the geothermal resource surface geochemical exploration method provided by the first embodiment of the present invention is shown. Figure 1 It can be seen that the method includes the following steps.

[0068] Sample collection steps: Determine the matching sampling grid according to the required exploration area, and then implement the collection operation to obtain samples according to the set sampling rules;

[0069] Analysis and measurement steps: for different types of samples, different equipment is used to measure the elements contained in the samples according to the sample measurement list; the sample measurement list contains the elements to be measured and the matching measurement equipment corresponding to different sample types;

[0070] Index optimization steps: Considering the interference effect of formation reaction, select elements with migration capacity and anti-interference that meet the requirements from the measured elements as geothermal chemical exploration indicators for different formation types;

[0071] Thermal reservoir identification steps: Determine the content of soluble inorganic salts and gas in the formation, and identify the location and type of thermal reservoirs based on the set high salt and low gas areas;

[0072] Thermal reservoir evaluation steps: For strata with thermal reservoirs, the cap rock score and reservoir score are calculated based on their geothermal chemical exploration indicators, and then the comprehensive score is calculated and used to achieve quantitative rating of thermal reservoir strata, combined with the corresponding thermal reservoir type output.

[0073] The surface geochemical exploration method for geothermal resources of the embodiment of the present invention is adopted, and a sample collection link, a sample determination link, an indicator optimization link, a pattern recognition link and a thermal reservoir evaluation link are set up, and a method for optimizing effective indicators is given, which can find thermal reservoir geochemical indicators with high correlation with thermal reservoirs, strong migration ability and good anti-interference performance. According to the "salt dissolving and gas coming out" theory of thermal reservoirs, a "high salt and low gas" thermal reservoir pattern recognition method is proposed, and a comprehensive evaluation method system for thermal reservoirs and caprocks is formed, which can effectively track, predict and evaluate geothermal resources in underlying strata, and can improve the exploration and application effect of existing technologies.

[0074] Specifically, in some embodiments of the present invention, in the sample collection step, a collection operation is carried out according to set sampling rules to obtain samples. Preferably, the sampling rules are set to include sample types and sampling methods, and the sampling methods are set corresponding to the sample types. The sample types include soil samples, soil gas samples and water samples. The soil samples and soil gas samples are collected by drilling to a set depth range using matching tools.

[0075] Furthermore, in some embodiments, the soil samples and soil gas samples are collected by drilling to a depth of 0.5m-2m using matching tools.

[0076] In actual application, the exploration area is set according to the needs, and then the sampling grid is determined according to the exploration area, and field sample collection is implemented. The samples collected include soil samples, soil gas samples and water samples; soil samples are collected after being drilled to a certain depth with tools such as twist drills, preferably 0.5-2m; soil gas samples can be collected after being drilled to a set depth with a matching ground gas collection spiral drill device, preferably within the sampling range of 0.5-2m; water samples are directly collected from reservoir water, seawater, geothermal drilling water, hot spring water, etc. using appropriate containers.

[0077] Furthermore, the analysis and determination step is performed to determine the elements contained in the samples using different equipment according to the sample determination list for different types of samples; wherein the sample determination list contains the elements to be determined corresponding to different types of samples and the matching determination equipment;

[0078] Optionally, in some embodiments of the present invention, for soil samples, the measurement equipment in the sample measurement list includes an X-ray fluorescence spectrometer, an inductively coupled plasma mass spectrometer, an emission spectrometer, an atomic fluorescence spectrometer, a polarograph and an ion selective electrode.

[0079] For soil gas samples, the measurement equipment in the sample measurement list includes a gas chromatograph with a hydrogen flame detector, a gas chromatograph with a thermal conductivity detector, and an isotope mass spectrometer;

[0080] For water samples, the measurement equipment in the sample measurement list includes inductively coupled plasma mass spectrometer and inductively coupled plasma spectrometer.

[0081] In actual application, for soil samples, the measurement process includes: using X-ray fluorescence spectrometer to measure K, Mg, Al, Si, P, K, Ca, Ba, Ti, V, Cr, Mn, Fe, Zn, Pb, Sr, Y, Zr, Nb, etc.; using inductively coupled plasma mass spectrometer to measure Li, Be, Co, Ni, Cu, Cd, La, Th, U, Au, etc.; using emission spectrometer to measure B, Sn, Ag, etc.; using atomic fluorescence spectrometer to measure As, Sb, Bi, Hg; using mercury meter to measure elemental Hg and combined Hg; using polarograph to measure W and Mo; and using ion selective electrode to measure F.

[0082] For soil gas samples, the measurement process includes:

[0083] The light hydrocarbon components of soil are determined by gas chromatograph with hydrogen flame detector, CO2, He, Ne, H2, etc. are determined by gas chromatograph with thermal conductivity detector; CH4 carbon isotope, CO2 carbon isotope and He isotope are determined by isotope mass spectrometer.

[0084] For water samples, the determination process includes: determining Li, Be, Ti, V, Cr, Co, Ni, Cu, Zn, Mo, Cd, Nb, Rb, Th, Ga, Ce, La, Y, Yb, etc. using an inductively coupled plasma mass spectrometer; determining K, Na, Ca, Mg, Fe, Mn, P, Al, Sr, Ba, etc. using an inductively coupled plasma spectrometer.

[0085] Next, perform the index optimization step, and select elements with migration ability and anti-interference ability meeting the requirements from the determined elements as geothermal chemical exploration indexes for different formation types considering the interference effects of formation reactions.

[0086] Considering to ensure the stability and flexibility of index application, embodiments of the present invention select factors with migration ability and anti-interference ability from indexes closely related to geothermal energy. Optionally, the index selection principle is: mainly select volatile gas indexes and water-soluble inorganic salt element indexes. Among them, in a preferred embodiment, mantle-derived gases and gases generated due to geothermal energy are selected as gas indexes.

[0087] Specifically, in some embodiments of the present invention, in the index optimization step, by measuring the isotope ratios of helium R ( 3 He / 4 He) and atmospheric helium Ra ( 3 He / 4 He) in the sample, when the isotope ratios meet the set mantle source standard, He is preferably used as a geothermal chemical exploration index.

[0088] In practical applications, taking the helium in conventional formations as an example, by measuring the isotope ratios of helium R ( 3 He / 4 He) and atmospheric helium Ra ( 3 He / 4 He) in the sample to determine whether it belongs to mantle-derived helium. Among them, when R / Ra > 1, it is determined to be mantle-derived helium, and at this time, preferably He can be used as a geothermal geochemical exploration index; when 0.1 < R / Ra < 1, it means that He is a crust-mantle mixed source, and when R / Ra < 0.1, it means that He is a crustal source. In these two cases, the geothermal indication significance of He is not strong and is not selected as the helium index.

[0089] Furthermore, in some embodiments of the present invention, in the index optimization step, by measuring the carbon isotope of CH4 in the sample: δ 13 C CH4，PDB (‰), when it meets the set index, CH4 is preferably used as a geothermal chemical exploration index.

[0090] Measure the carbon isotope of CO2 in the sample: δ 13 C CO2，PDB(‰) When it meets the set inorganic origin criteria, CO2 is preferred as a geothermal chemical exploration indicator.

[0091] In practical application, the carbon isotope distribution of CH4 in the sample is determined: when δ 13 C CH4，PDB (‰)>-55‰, CH4 is preferred as a geothermal geochemical exploration indicator; when δ 13 C CH4，PDB When (‰) < -56‰, it indicates that CH4 is caused by surface microbial action, and the geothermal indication is not strong;

[0092] Determination of CO2 carbon isotope in samples: When δ 13 C CO2，PDB When δ is between -8‰ and 3‰, it is of inorganic origin, and CO2 can be used as a geothermal geochemical exploration indicator; 13 C CO2，PDB (‰) < -10‰ indicates that the CO2 is of organic origin and has a weak geothermal indication;

[0093] C2H6、C3H8、C 2+ Indicators such as CH4 (the sum of components of light hydrocarbons after CH4) are generated by thermal action of organic matter in the formation and cannot be generated under surface conditions. They can be used as geothermal geochemical exploration indicators.

[0094] Element index optimization method: The indexes with high concentration in hot water can be optimized by measuring the element composition and content of outcrop hot spring water and geothermal drilling water.

[0095] In addition, in the process of selecting gas indicators, it is necessary to consider the impact of formation characteristics on formation gas components. If the formation characteristics include other reactions that directly affect the enrichment and dilution effects of gas in the formation, then the current others cannot be used as gas indicators for the relevant formation, so as not to affect the accuracy of the overall geothermal geochemical exploration of the formation.

[0096] Therefore, in some optional embodiments, in the index optimization step, if the distribution degree of granite in the current formation meets the set requirements, He and Rn are not selected as geothermal chemical exploration indicators;

[0097] If the minerals in the current stratum can undergo water-rock reaction to generate H2, H2 is not selected as a geothermal chemical exploration indicator;

[0098] If the current stratum belongs to the effective farmland area or the time of agricultural withdrawal is within the set time period, N, P and K elements are not selected as geothermal chemical exploration indicators;

[0099] If the current stratum belongs to the seawater intrusion area or saline-alkali area, do not select K, Na, Ca, Mg, Cl, Br, and S elements;

[0100] If the current stratum belongs to a rich mineral area, elements whose content in the minerals reaches the set conditions will not be selected.

[0101] Specifically, in practical applications, in areas where granite strata are widely distributed, He and Rn will be generated by the decay of radioactive elements therein. Therefore, it is not appropriate to select He and Rn as geothermal geochemical exploration indicators.

[0102] In areas where minerals in underground strata can undergo water-rock reactions to generate H2, H2 is not selected as a geothermal geochemical exploration indicator.

[0103] In the farmland area, element indicators such as N, P, and K are not selected;

[0104] In seawater intrusion areas and saline-alkali areas, element indicators such as K, Na, Ca, Mg, Cl, Br, and S are not selected;

[0105] In rich ore areas, element indicators with high content in minerals are not selected.

[0106] Temperature controls the concentration changes of three media: water, inorganic salts in surrounding rocks, and gas. The existence of geothermal resources will lead to "salt-dissolved gas".

[0107] "Salt dissolution" means that the existence of heat reservoirs will cause the surrounding strata temperature to rise accordingly, and will also cause the strata water temperature to rise, the solubility of soluble inorganic salts in the surrounding rocks to increase, and the mineralization of water to increase.

[0108] "Gas out" means that the existence of heat storage will cause the temperature of the surrounding formations to rise accordingly, promoting the continuous expansion and volatilization of gas in the formation and its upward migration and dissipation, resulting in a decrease in the gas concentration in the formation; at the same time, it also causes the gas dissolved in the formation water to evaporate as the temperature rises and migrate upward and dissipate, resulting in a decrease in the concentration of dissolved gas in the water.

[0109] The "salt dissolution and gas release" of thermal reservoirs will lead to the "high salt and low gas" surface geochemical anomaly pattern of thermal reservoirs. "High salt" surface geochemical anomaly pattern: The existence of thermal reservoirs will increase the temperature of the surrounding strata accordingly, resulting in an increase in the solubility of soluble inorganic salts in the surrounding rocks. The dissolved inorganic salts will migrate with water. Water has strong wettability and permeability to the strata, and can carry inorganic salts to diffuse and migrate to the strata above, resulting in a high concentration field feature of inorganic salts in the strata above the thermal reservoir.

[0110] "Gas is low" surface geochemical anomaly pattern: The presence of a heat reservoir will increase the temperature of the surrounding strata accordingly, resulting in a decrease in the concentration of gas in the strata and dissolved gas in the formation water, causing the gas in the upper strata to present a low concentration field characteristic. Therefore, the surface geochemical anomaly pattern of the geothermal system is "high salt and low gas". Under the same conditions, the higher the temperature of the heat reservoir, the more obvious the "high salt and low gas" feature is, and the greater the degree is.

[0111] Furthermore, the migration content of soluble inorganic salts in the formation and the content of gas in the formation are determined through the heat reservoir identification step, and the location where the heat reservoir exists is determined in combination with the set high-salt area and low-gas area identification conditions;

[0112] Among them, there are "high salt" areas and "low gas" areas, and the "high salt" and "low gas" areas overlap, which can determine the existence of heat reservoirs in the underlying strata of the area.

[0113] Therefore, in some preferred embodiments, in the heat reservoir identification step, the locations where both high-salt areas and low-gas areas exist and where the "high-salt" areas and the "low-gas" areas overlap are identified and determined to be locations where heat reservoirs exist in the underlying strata; the high-salt areas are set to have an inorganic salt content greater than or equal to the mean of the exploration area plus n times the standard deviation (n>0); and the low-gas areas are set to have a gas content less than or equal to the mean of the exploration area minus n times the standard deviation (n>0).

[0114] The researchers of this invention took into account that there must be the characteristics of "high salt and low gas" above the heat reservoir, but there may not be a heat reservoir below the "high salt and low gas". For example, after magma intrudes into the middle and shallow strata, it cools down due to the poor insulation effect of the cap layer and cannot become a heat reservoir. Therefore, after finding the location of "high salt and low gas", it is necessary to find evidence that the heat source continuously supplies heat to the "high salt and low gas" area, that is, to identify the heat-controlling faults, heat transfer channels and heat transfer directions at the same time, and then confirm that the "high salt and low gas" area is the location of the heat reservoir.

[0115] The present invention determines the migration content of soluble inorganic salts and the content of gas in the formation, and identifies the location of the heat reservoir in combination with the set salt high and gas low indicators; determines the content of elemental Hg and combined Hg in the formation, and identifies the location of the heat transfer channel, heat-controlling fractures, and heat transfer direction in combination with the set elemental Hg and combined Hg high value bands; determines the content of Na, K, and Ca in the formation, and identifies the location of the water transfer channel, water supply fractures, and water transfer direction in combination with the set Na, K, and Ca high value bands; determines the content of Nb, W, Mo, U, and Th in the formation, and identifies the location of hot dry rocks in combination with the set Nb, W, Mo, U, and Th high value areas; and further identifies the type of heat reservoir.

[0116] Mercury is volatile, and its vapor pressure increases with increasing temperature, which results in a thermal evaporation effect. At the same time, mercury is also reducible, and will be oxidized into combined Hg after being transported to the surface. The main source of mercury is the mantle source. Mercury is a geochemical identification indicator that reflects the "present ongoing" tense of heat source heating activities. If both the monosemic Hg and combined Hg on the ground show high concentration field characteristics at the same time, it reflects that the heat source heating activities are ongoing and there is heat storage. If the surface combined Hg shows high concentration field characteristics and the high concentration field characteristics of mercury are not obvious, it reflects that the heating activities have stopped, but there are ancient heating activities and no heat storage. Therefore, the concentration characteristics of monosemic Hg and combined Hg on the ground can be used to judge the heat source heating activities and predict heat storage, and to track the heat source, identify heat-controlling faults, and judge the heat transfer channel and heat transfer direction.

[0117] Hydrothermal and combined hydrothermal and hot dry rock heat reservoirs need to be supplied with water through water supply fractures. Without fractures leading to underground formations, it is difficult to directly supply surface water. The water transmission channel is the connecting channel between surface water and hydrothermal heat reservoirs. Surface water supply is a slow process. The soluble inorganic salt ions in hot water will exchange with surface water through the water transmission channel and migrate to the surface, forming high value anomalies. The identification indicators of water supply fractures with soluble ions Na, K, and Ca are preferred.

[0118] Since granite has good thermal conductivity, hot dry rocks are mostly granite, which is rich in Nb, W, Mo, U, and Th. They will be carried to the surface by water and gas to form high-value anomalies. Nb, W, Mo, U, and Th indicators are preferred to identify the location of hot dry rock heat reservoirs.

[0119] Considering the existence of heat storage, heat control fractures are also needed for heating. There is a heat transfer channel between the heat control fracture and the heat storage. The identification method of the heat transfer channel is: there are high-value bands of indicators such as elemental Hg and combined Hg. The identification mode of the heat transfer channel is "high elemental Hg and high combined Hg". The highest values ​​of elemental Hg and combined Hg are the locations of the heat control fractures, and the heat transfer direction is from the heat control fracture to the heat storage.

[0120] Specifically, in the heat transfer channel identification step, the high-value band of each index of elemental Hg and combined Hg is the location of the heat transfer channel, and the identification standard of the band is set as the index content is greater than or equal to the mean value of the exploration area plus n times the standard deviation, starting from the fracture and ending at the heat reservoir, the combined maximum value of elemental Hg and combined Hg is the heat control fracture position, and the heat transfer direction is from the heat control fracture to the heat reservoir. In practical application, if the high-value band of elemental Hg and combined Hg is identified at the same time, and the two are basically overlapped, it is determined to be the location of the heat transfer channel; the high-value band is set as the content of elemental Hg and combined Hg is greater than or equal to the mean value of the exploration area plus n times the standard deviation (n>0), the position of the band starts from the fracture and ends at the heat reservoir, the identification mode of the heat transfer channel is "high elemental mercury and high combined mercury", the highest value of elemental Hg and combined Hg is the heat control fracture position, and the heat transfer direction is from the heat control fracture to the heat reservoir.

[0121] Considering that the existence of hydrothermal heat reservoirs requires water supply fractures, the geochemical identification method of water transmission channels is: the existence of high-value zones of indicators such as Na, K, and Ca, which starts from the fractures and ends at the heat reservoir; the identification mode of water transmission channels is "high sodium, high potassium, and high calcium", the highest values ​​of indicators such as Na, K, and Ca are the locations of water supply fractures, and the direction of water transmission is from the water supply fractures to the heat reservoir; the existence of high-salt and low-gas areas, heat transmission channels, and water transmission channels can identify the heat reservoir as a hydrothermal heat reservoir.

[0122] Specifically, in a preferred embodiment, in the water transmission channel identification step, the high-value band of each indicator of Na, K, and Ca is the location of the water transmission channel, and the identification standard of the band is set to the indicator content being greater than or equal to the mean value of the exploration area plus n times the standard deviation, starting from the fracture and ending at the heat storage, the comprehensive highest value of the Na, K, and Ca indicators is the water supply fracture position, and the water transmission direction is from the water supply fracture to the heat storage. In actual application, in the water transmission channel identification step, the high-value bands of Na, K, and Ca are identified to exist at the same time, and the three are basically overlapped, that is, high sodium, high potassium, and high calcium, and the location of the water transmission channel is determined; wherein, the high-value band is set to the content of Na, K, and Ca being greater than or equal to the mean value of the exploration area plus n times the standard deviation (n>0), and the location of the band starts from the fracture and ends at the heat storage; the identification mode of the water transmission channel is "high sodium, high potassium, and high calcium", the highest value of the indicators such as Na, K, and Ca is the water supply fracture position, and the water transmission direction is from the water supply fracture to the heat storage; if there is a high-salt and low-gas area, a heat transmission channel, and a water transmission channel, the heat storage can be identified as a hydrothermal heat storage.

[0123] Hot dry rock reservoirs are generally intrusive rock formations, mostly granite. Intrusive rocks are rich in high-temperature elements such as Nb, W, and Mo. If the intrusive rock is granite, it is also rich in U and Th. The identification method of hot dry rocks is: in high-salt areas and low-gas areas, there are high-value zones of indicators such as Nb, W, Mo, U, and Th. At the same time, the high-value zone is in or near the overlapping area of ​​high salt and low gas; the identification mode of hot dry rocks is "high niobium, high tungsten, high molybdenum, high uranium, and high thorium".

[0124] In one embodiment, in the step of identifying the location of hot dry rocks, if there are high-value bands of each of the indicators Nb, W, Mo, U, and Th, and the identification standard of the band is set to that the indicator content is greater than or equal to the mean of the exploration area plus n times the standard deviation, and the high-value band area is located within or within a set range near the overlapping area of ​​high salt and low gas, then the area is identified and determined to be a hot dry rock distribution area.

[0125] In actual application, in the step of identifying hot dry rock type thermal reservoirs, the high value areas of Nb, W, Mo, U, and Th are identified to exist simultaneously, and the five are basically overlapped, and are determined to be the location of hot dry rocks; wherein, the high value areas of Nb, W, Mo, U, and Th are set to have Nb, W, Mo, U, and Th contents greater than or equal to the mean of the exploration area plus n times the standard deviation (n>0), and the location of the high value areas is in or near the overlapping area of ​​high salt and low gas, and the identification mode of hot dry rocks is "high niobium, high tungsten, high molybdenum, high uranium, and high thorium"; if there are high salt and low gas areas and heat transfer channels, and there are high value areas of Nb, W, Mo, U, and Th at the same time, the thermal reservoir can be identified as a hot dry rock type thermal reservoir; if there are high salt and low gas areas, heat transfer channels, and water transfer channels, and there are high value areas of Nb, W, Mo, U, and Th at the same time, the thermal reservoir can be identified as a combined hydrothermal-hot dry rock type thermal reservoir.

[0126] Next, the thermal reservoir evaluation step is performed. For the strata with thermal reservoirs, the cap rock score and reservoir score are calculated based on their geothermal chemical exploration indicators, and then the comprehensive score is calculated and the quantitative rating of the thermal reservoir strata is achieved based on it.

[0127] For the surface geochemical anomaly area, the higher the "salt high", the higher the heat storage temperature; the lower the "gas low", the better the thermal insulation effect of the cap layer, and the degree of high and low can be quantitatively rated. Among them, the degree of high and low is quantitatively rated by calculating the score.

[0128] Further, in an optional embodiment, in the thermal reservoir evaluation step, the cap rock score of the formation is calculated according to the following formula:

[0129]

[0130] The reservoir score of a formation is calculated as follows:

[0131]

[0132] Then calculate the comprehensive score: D = D 盖 +D 储 ,

[0133] Where D 盖 Score for the cap layer, G i is the content of gas component, is the regional mean of gas component content; D 储 is the reservoir score, C i is the content of inorganic salt elements, is the regional mean of inorganic salt element content, and D is the comprehensive score.

[0134] Among them, D 盖 The larger the value, the better the caprock and, to a certain extent, the higher the thermal reservoir temperature. 储 The larger the value, the better the reservoir. The larger the D= value, the richer the underlying stratum. Based on this, we can calculate the sum of multiple indicators of "high salt and low gas" and divide it by the number of indicators used to calculate value, The percentage that indicates the degree of influence of heat storage on gas dilution effect and element enrichment effect is used to evaluate the heat storage temperature. If necessary, it can be calibrated with the temperature of known geothermal wells in the area.

[0135] Therefore, in some embodiments, in the thermal storage evaluation step, the comprehensive scores corresponding to multiple indicators are summed and then divided by the number of indicators used to obtain an average comprehensive score, which represents the percentage of the influence of the thermal storage on the gas dilution effect and the element enrichment effect, and the thermal storage temperature level is determined based on its value and the set associated evaluation rules.

[0136] According to the geothermal resource temperature classification standard of "Geothermal Resource Geological Exploration Specification (GB / T 11615-2010)": high temperature geothermal resources (T≥150℃), medium temperature geothermal resources (90≤T<150℃), low temperature geothermal resources (25≤T<90℃). Thermal reservoir evaluation classification method: Values ​​ranging from 5 to 15 are evaluated as low-temperature geothermal fields; The value range of 15-25 is evaluated as medium-temperature geothermal field; A value of 25 points or more is evaluated as a high-temperature geothermal field.

[0137] The present invention is further described below in conjunction with examples of implementation. The scope of the present invention is not limited by the examples, but is set forth in the claims.

[0138] Implementation Case 1: Taking the geothermal surface geochemical exploration in the Huangshadong geothermal field exploration area in Huizhou City, Guangdong Province as an example, in 2020, a 216km2 geothermal exploration project was carried out in the Huangshadong geothermal field. 2The sampling and analysis test work of the chemical detection network is carried out; the coordinates of the four turning points in the exploration area are (23°14'39.70" North, 114°33'25.86" East), (23°19'20.20" North, 114°38'18.25" East), (23°7'18.17" North, 114°41'11.63" East), (23°11'58.42" North, 114°46'3.95" East), the sampling points are 2km×2km apart, 70 physical sampling points are deployed, 70 soil samples, 70 soil gas samples and 4 water samples are collected.

[0139] Sampling method: Soil samples are collected after the twist drill reaches 1.0-1.5m; soil gas samples are collected after the ground gas collection spiral drill reaches 1.0-1.5m; water samples are collected directly from reservoir water, sea water, hot spring water, etc. using containers.

[0140] Determination method: The determination of light hydrocarbons in soil gas is carried out by gas chromatograph with hydrogen flame detector, the determination of carbon dioxide in soil gas is carried out by gas chromatograph with thermal conductivity detector, and the determination of helium-neon hydrogen in soil gas is carried out by gas chromatograph with thermal conductivity detector;

[0141] Some gas samples were measured for CH4 carbon isotope, CO2 carbon isotope and He isotope using isotope mass spectrometer; soil element determination was carried out using the rules shown in Table 2; water sample determination was carried out using the rules shown in Table 1, and the measurement results are shown in Table 5.

[0142] Table 1 Water sample determination method

[0143]

[0144] Table 2 Determination methods of soil inorganic elements

[0145]

[0146]

[0147] Gas index optimization method: The analysis data of CH4 and CO2 carbon isotopes and He isotopes in the soil gas in the Huangsha Cave exploration area of ​​Huizhou City are shown in Tables 3 and 4. The CH4 carbon isotope is -54.4‰, which is basically of biological origin; the CO2 carbon isotope is between -20.1‰ and -21.4‰, which is of organic origin; the He isotope is 0.1<R / Ra<1, which is of mixed crust-mantle origin.

[0148] It can be seen that both CH4 and CO2 are disturbed to a certain extent by the action of surface microorganisms; the He of crustal origin indicates the existence of granite below, but it is not necessarily a heat reservoir, so He and Rn indicators are not recommended. 2+(the sum of components of light hydrocarbons after CH4) and other indicators are used as geothermal geochemical exploration indicators.

[0149] Element index optimization method: As shown in Table 5, the Ba, Be, Cr, Fe, Ga, Li, Mn, Rb, Ti, V, and Zn in the Huilin hot spring water at the outcrop of the Huangshadong geothermal field are all higher than those in surface water, and can be selected as geothermal geochemical exploration indicators.

[0150] Table 3 CH4 and CO2 carbon isotope data in Huizhou City, Guangdong Province

[0151] Sample number area <![CDATA[CH4-δ 13 CPDB(‰)]]> <![CDATA[CO2-δ 13 CPDB(‰)]]> 15-5 Huangsha Cave, Huizhou City -54.427 -20.622 13-7 Shiba Town, Huizhou City -61.727 -21.125 9-6 Shiba Town, Huizhou City -52.836 -20.151

[0152] Table 4 He isotope data of Huizhou City, Guangdong Province

[0153]

[0154]

[0155] Table 5 Water chemical analysis data of Huangsha Cave Exploration Area in Huizhou City (μg / L, ND means not detected)

[0156]

[0157] Thermal reservoir identification method: The high content of Fe, Ti, V, Ba, Be, Cr, Ga, Li, Mn, Rb, and Zn elements in the Huilin hot spring water at the outcrop of the Huangshadong geothermal field has formed a high value anomaly in the soil above the geothermal field, verifying the scientific nature of the "salt high" geochemical anomaly model. 2+ The inorganic gases Ne, H2, CO2, etc. all show low value anomalies, which verifies the scientific nature of the "gas low" geochemical anomaly model.

[0158] Choose Fe, Ti, V, Cr, C2H6, C2H6, C 2+ , H2 index to draw concentration contour map, such as Figure 2 As shown; the Huangshadong abnormal area is delineated. In actual application, the high salt area can be set to ≥ the exploration area mean plus 0.5 times the standard deviation; the low gas area can be set to ≤ the exploration area mean minus 0.5 times the standard deviation, that is, the high salt area is set to the inorganic salt content greater than or equal to the exploration area mean plus n times the standard deviation (n>0); the low gas area is set to the gas content less than or equal to the exploration area mean minus n times the standard deviation (n>0). Figure 2 It can be seen that the areas of "high salt and low gas" are highly overlapped, and the underlying strata of the delineated Huangshadong anomaly area are confirmed to contain heat reservoirs.

[0159] Select elemental Hg and combined Hg indicators to plot concentration contour lines, such as Figure 3As shown in the figure, the heat-conducting fault is identified as F fault, the heat-controlling fault is Tonghu fault, and the heat transfer direction is from Tonghu fault to heat reservoir via F heat-conducting fault (marked by purple hollow arrows in the figure). In practical application, the high-value bands of elemental Hg and combined Hg can be set to ≥ the mean value of the exploration area plus 0.5 times the standard deviation.

[0160] Select Na, K, and Ca indicators to plot concentration contour lines, such as Figure 4 As shown in the figure, the water supply faults are identified as SF1, SF2, and SF3 faults, and the water transmission direction is from SF1, SF2, and SF3 faults to the Huangshadong thermal-rich area (marked by blue hollow arrows in the figure), indicating that there are hydrothermal geothermal resources in the underlying strata. In practical applications, the high-value zones of Na, K, and Ca can be set to ≥ the mean of the exploration area plus 0.5 times the standard deviation.

[0161] Select Nb, W, Mo, U, Th, and Rn indicators to plot concentration contour lines, such as Figure 5 As shown in the figure, Nb, W, Mo, U, and Th show high values ​​above the geothermal field, with a consistent trend. It is judged that there is intrusive rock in the underlying stratum, and it is predicted that the intrusive rock in the underlying stratum is granite, which comes from the Tonghu fault or the Zijin-Boluo fault (NE direction) about 10 km northwest of the exploration area boundary; the underlying intrusive rock is predicted to be a shallow granite buried area, and the presence of hot dry rock is predicted. In practical application, the high-value area of ​​Nb, W, Mo, U, and Th can be set to ≥ the mean of the exploration area plus 0.5 times the standard deviation.

[0162] Comprehensively judged that the Huangshadong geothermal field is a combination of hydrothermal and hot dry rock geothermal resources.

[0163] Existing exploration results believe that the Huangshadong geothermal field is mainly located near the Huangshadong village. The exploration results using the method of the present invention show that the scope of the Huangshadong geothermal field should expand to the southwest and be distributed in a belt-like manner under the control of faults.

[0164] Thermal reservoir evaluation method: The mean values ​​of the indicators in the Huangsha cave exploration area and the mean values ​​in the abnormal area were statistically analyzed and compared, and the results are shown in Table 6; the degree of “high salt and low gas” was calculated, and the results are shown in Table 7. The value is 20.2, which is identified as a medium-temperature geothermal resource. The water temperature of the outcropping Huilin Hot Spring is 93°C, and the bottom temperature of the Huire 1 well in the Huangshadong geothermal field is 128°C at a depth of 3009m. These data support the effectiveness of the method of the present invention.

[0165] Table 6 Comparison of the mean values ​​of indicators in the Huangsha Cave exploration area in Huizhou City, Guangdong Province and the mean values ​​of the abnormal area

[0166]

[0167] Table 7 Thermal reservoir evaluation score table of Huangsha Cave Exploration Area in Huizhou City, Guangdong Province (%)

[0168]

[0169] Implementation Case 2: Taking the geothermal surface geochemical exploration in the Shiba Basin exploration area of ​​Huizhou City, Guangdong Province as an example, in 2020, a 228km2 geothermal surface geochemical exploration project was implemented in Shiba Town. 2 The chemical detection network has four turning points in the exploration area with coordinates of (23°14'39.70" North, 114°26'55.25" East), (23°34'42.81" North, 114°31'48.49" East), (23°22'38.74" North, 114°34'39.46" East), and (23°27'18.81" North, 114°39'32.63" East). The sampling points are 1km×1km apart. 260 profile physical points are deployed, and 260 soil samples and 260 soil gas samples are collected.

[0170] Since the Shiba Basin exploration area is about 20 km away from the Huangshadong exploration area, the same sampling method, measurement method, indicator optimization method, pattern recognition method and thermal reservoir evaluation method are used.

[0171] Choose Fe, Ti, V, Cr, C2H6, C2H6, C 2+ , H2 index to draw concentration contour map, such as Figure 6 As shown in the figure, three geothermal favorable areas are delineated, namely, Shiba No. 1 anomaly area, Shiba No. 2 anomaly area, and Shiba No. 3 anomaly area. The high salt area is ≥ the regional mean plus 0.5 times the standard deviation; the low gas area is ≤ the regional mean minus 0.5 times the standard deviation. Figure 3 It can be seen that the areas of "high salt and low gas" are highly overlapping, and the underlying strata of the three geothermal favorable areas identified are confirmed to contain heat reservoirs.

[0172] Select elemental Hg and combined Hg indicators to plot concentration contour lines, such as Figure 7 As shown in the figure, the heat-controlling fault is identified as the Heyuan Deep Fault, and the heat transfer direction is from the Heyuan Deep Fault to the Shiba No. 1 favorable area, Shiba No. 2 favorable area, and Shiba No. 3 favorable area (marked by purple hollow arrows in the figure). In practical application, the high-value bands of elemental Hg and combined Hg can be set to ≥ the mean of the exploration area plus 0.5 times the standard deviation.

[0173] Select Na, K, and Ca indicators to plot concentration contour lines, such as Figure 8As shown in the figure, the water supply fault of Shiba No. 1 favorable area is identified as Heyuan Deep Fault; the water supply faults of Shiba No. 2 and Shiba No. 3 favorable areas are Heyuan Deep Fault and Zijin-Boluo Fault; the water transmission direction is Heyuan Deep Fault to Shiba No. 1, Shiba No. 2, Shiba No. 3 favorable areas, and Zijin-Boluo Fault to Shiba No. 2 and Shiba No. 3 favorable areas (marked with blue hollow arrows in the figure); hydrothermal geothermal resources exist in Shiba No. 1, Shiba No. 2, and Shiba No. 3 favorable areas. In practical application, the high value zone of Na, K, and Ca can be set to ≥ the mean of the exploration area plus 0.5 times the standard deviation.

[0174] Select Nb, W, Mo, U, Th, and Rn indicators to plot concentration contour lines, such as Fig. 9 As shown in the figure, N Nb, W, Mo, U, Th and Rn show high values ​​above Shiba No. 1 favorable area, Shiba No. 2 favorable area and Shiba No. 3 favorable area, and the trend is consistent. It is judged that there are intrusive rocks in the underlying strata, and the intrusive rocks in the underlying strata are predicted to be granites, which come from the Heyuan Deep Fault and the Zijin-Boluo Fault; it is predicted that the underlying intrusive rocks in Shiba No. 1 favorable area, Shiba No. 2 favorable area and Shiba No. 3 favorable area are shallowly buried granites, and there are hot dry rocks in all of them. In practical application, the high-value area of ​​Nb, W, Mo, U and Th can be set to ≥ the mean value of the exploration area plus 0.5 times the standard deviation.

[0175] Comprehensively judging that the favorable areas of Shiba No. 1, Shiba No. 2 and Shiba No. 3 are combined geothermal resources of hydrothermal and hot dry rock.

[0176] Thermal reservoir evaluation method: The average value of the Shiba exploration area index and the average value of the abnormal area are statistically compared, and the results are shown in Table 8; the degree of "high salt and low gas" is calculated, and the results are shown in Table 9. The values ​​are 31, 24.8, and 28.2 respectively. The Shiba No. 1 anomaly area is judged as a high-temperature geothermal resource, and the Shiba No. 2 and Shiba No. 3 anomaly areas are judged as medium-temperature geothermal resources. Based on the calibration of the Huire 1 well in Huangshadong (depth 3009m, bottom temperature 128℃), it is predicted that the highest heat storage temperatures at 3009m in the Shiba No. 1, Shiba No. 2, and Shiba No. 3 anomaly areas are 196℃, 157℃, and 179℃ respectively, all of which are high-temperature geothermal resources.

[0177] Table 8 Comparison of the mean values ​​of indicators in Shiba Basin, Huizhou City, Guangdong Province and the mean values ​​of abnormal areas

[0178]

[0179]

[0180] Table 9: Thermal reservoir evaluation score table of Shiba Basin, Huizhou City, Guangdong Province (%)

[0181]

[0182] Based on the surface geochemical exploration theory of "salt dissolving and gas coming out" of thermal reservoirs, the present invention establishes a surface geochemical anomaly model of "high salt and low gas", forms a technical system for surface geochemical exploration of thermal reservoirs and an effective cover evaluation technology system, and establishes a quantitative evaluation method for surface geochemical anomalies and a geothermal resource prediction method.

[0183] For the above-mentioned method embodiments, for the sake of simplicity, they are all described as a series of action combinations, but those skilled in the art should know that the present invention is not limited by the order of the actions described, because according to the present invention, some steps can be performed in other orders or simultaneously. Secondly, those skilled in the art should also know that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily required by the present invention.

[0184] It should be pointed out that in other embodiments of the present invention, the method can also obtain a new surface geochemical exploration method for geothermal resources by combining one or several of the above embodiments to achieve accurate and efficient exploration of geothermal resources.

[0185] It should be noted that, based on the method in any one or more of the above-mentioned embodiments of the present invention, the present invention also provides a storage medium, on which is stored a program code that can implement the method as described in any one or more of the above-mentioned embodiments, and when the code is executed by the operating system, it can implement the above-mentioned surface geochemical exploration method for geothermal resources.

[0186] Embodiment 2

[0187] The above embodiments disclosed in the present invention describe the method in detail. The method of the present invention can be implemented by various devices or systems. Therefore, based on other aspects of the method described in any one or more embodiments, the present invention also provides a geothermal resource surface geochemical exploration system, which is used to execute the geothermal resource surface geochemical exploration method described in any one or more embodiments. Specific embodiments are given below for detailed description.

[0188] Specifically, Fig.10 FIG. 4 is a schematic diagram showing the structure of a geothermal resource surface geochemical exploration system provided in an embodiment of the present invention. Fig.10 As shown, the system includes:

[0189] The sample collection module is configured to determine the matching sampling grid according to the required exploration area range, and then implement the collection operation to obtain samples according to the set sampling rules;

[0190] The analysis and determination module is configured to use different equipment to determine the elements contained in the samples according to a preset sample determination list for different types of samples; the sample determination list contains the elements to be determined and the matching determination equipment corresponding to different sample types;

[0191] An index optimization module is configured to select elements whose migration capacity and anti-interference performance meet the requirements from the measured elements in consideration of the influence of formation reaction as geothermal chemical exploration indicators for different formation types;

[0192] A heat reservoir identification module, which is configured to determine the content of soluble inorganic salts and the content of gas in the formation, and identify the location and type of heat reservoirs in combination with the set high salt and low gas areas;

[0193] The thermal reservoir evaluation module is configured to calculate the cap rock score and reservoir score for the strata with thermal reservoirs based on their geothermal chemical exploration indicators, and then calculate the comprehensive score and implement the quantitative rating of the thermal reservoir strata based on it, combined with the corresponding thermal reservoir type output.

[0194] Preferably, in some embodiments of the present invention, the sample collection module is configured as follows: setting sampling rules including sample type and sampling method, the sampling method is set corresponding to the sample type, the sample types include soil samples, soil gas samples and water samples, and the soil samples and soil gas samples are collected by drilling to a set depth range using matching tools.

[0195] In some embodiments of the present invention, the soil samples and soil gas samples are collected by drilling to a depth of 0.5m-2m using matching tools.

[0196] Further, in some embodiments of the present invention, for soil samples, the measuring equipment in the sample measuring list includes an X-ray fluorescence spectrometer, an inductively coupled plasma mass spectrometer, an emission spectrometer, an atomic fluorescence spectrometer, a mercury analyzer, a polarograph, and an ion selective electrode;

[0197] For soil gas samples, the measurement equipment in the sample measurement list includes a gas chromatograph with a hydrogen flame detector, a gas chromatograph with a thermal conductivity detector, and an isotope mass spectrometer;

[0198] For water samples, the measurement equipment in the sample measurement list includes inductively coupled plasma mass spectrometer and inductively coupled plasma spectrometer.

[0199] Optionally, in some embodiments of the present invention, the index optimization module measures the sample helium R( 3 He / 4 He) and atmospheric helium Ra ( 3 He / 4When the isotope ratio meets the set mantle source standard, He is preferably used as a geothermal chemical exploration indicator.

[0200] Furthermore, by measuring the carbon isotope of CH4 in the sample: δ 13 C CH4，PDB (‰), when it meets the set indicators, CH4 is preferred as the geothermal chemical exploration indicator;

[0201] Determine the sample CO2 carbon isotope: δ 13 C CO2，PDB (‰) When it meets the set inorganic origin criteria, CO2 is preferred as a geothermal chemical exploration indicator.

[0202] In some embodiments of the present invention, the index optimization module is configured as follows: if the distribution degree of granite in the current formation reaches the set requirements, He and Rn are not selected as geothermal chemical exploration indicators;

[0203] If the minerals in the current stratum can undergo water-rock reaction to generate H2, H2 should not be selected as a geothermal chemical exploration indicator.

[0204] If the current stratum belongs to the effective farmland area or the time of agricultural withdrawal is within the set time period, N, P and K elements are not selected as geothermal chemical exploration indicators;

[0205] If the current stratum belongs to the seawater intrusion area or saline-alkali area, do not select K, Na, Ca, Mg, Cl, Br, and S elements;

[0206] If the current stratum belongs to a rich mineral area, elements whose content in the minerals reaches the set conditions will not be selected.

[0207] In some embodiments of the present invention, the heat reservoir identification module identifies locations where both high-salt areas and low-gas areas exist and where the "high-salt" areas and "low-gas" areas overlap, and determines them as locations where heat reservoirs exist in the underlying strata.

[0208] The heat reservoir identification module includes: a heat transfer channel identification unit, which is configured to determine the content of elemental mercury and compound mercury in the formation, and identify the location of the heat transfer channel, the heat control fracture, and the heat transfer direction in combination with the set elemental mercury and compound mercury high value bands;

[0209] A water transmission channel identification unit configured to determine the Na, K, and Ca contents in the formation, and identify the location of the water transmission channel, water supply fracture, and water transmission direction in combination with the set Na, K, and Ca high value bands;

[0210] A hot dry rock position identification unit, which is configured to determine the content of Nb, W, Mo, U, and Th in the formation, and identify the position of the hot dry rock in combination with the set high-value area of ​​Nb, W, Mo, U, and Th;

[0211] The heat reservoir type identification unit is configured to identify the heat reservoir as a hydrothermal type heat reservoir when there are high-salt and low-gas zones, heat transfer channels, and water transfer channels at the same time; identify the heat reservoir as a hot dry rock type heat reservoir when there are high-salt and low-gas zones, heat transfer channels, and high-value zones of Nb, W, Mo, U, and Th; identify the heat reservoir as a hydrothermal-hot dry rock combination heat reservoir when there are high-salt and low-gas zones, heat transfer channels, and water transfer channels, and high-value zones of Nb, W, Mo, U, and Th.

[0212] In a preferred embodiment, the heat transfer channel identification unit is configured to perform the following operations: a band with high values ​​of each indicator of elemental Hg and combined Hg is the location of the heat transfer channel, the identification standard of this band is set to the indicator content being greater than or equal to the mean value of the exploration area plus n times the standard deviation, starting from the fracture and ending at the heat reservoir, the combined highest value of elemental Hg and combined Hg is the heat-controlled fracture position, and the heat transfer direction is from the heat-controlled fracture to the heat reservoir.

[0213] Furthermore, the water transmission channel identification unit is configured to perform the following operations: if there is a high-value band of Na, K, and Ca indicators as the location of the water transmission channel, the identification standard of the band is set to the indicator content being greater than or equal to the mean of the exploration area plus n times the standard deviation, starting from the fracture and ending at the heat reservoir, the combined highest value of the Na, K, and Ca indicators is the water supply fracture location, and the water transmission direction is from the water supply fracture to the heat reservoir.

[0214] Optionally, in one embodiment, the hot dry rock position identification unit is configured to perform the following operations: if there are high-value bands of each indicator Nb, W, Mo, U, and Th, the identification standard of the band is set to that the indicator content is greater than or equal to the mean of the exploration area plus n times the standard deviation, and the high-value band area is located within or within a set range near the overlapping area of ​​high salt and low gas, then the area is identified as a hot dry rock distribution area; the identification mode of hot dry rocks is "high niobium, high tungsten, high molybdenum, high uranium, and high thorium".

[0215] The thermal reservoir evaluation module is configured to calculate the cap rock score of the formation according to the following formula:

[0216]

[0217] The reservoir score of a formation is calculated as follows:

[0218]

[0219] Then calculate the comprehensive score: D = D 盖 +D 储 ,

[0220] Where D 盖 Score for the cap layer, G i is the content of gas component, is the regional mean of gas component content; D 储is the reservoir score, C i is the content of inorganic salt elements, is the regional mean of inorganic salt element content, and D is the comprehensive score.

[0221] Furthermore, in some embodiments of the present invention, the thermal storage evaluation module is configured to sum up the comprehensive scores corresponding to multiple indicators, and then divide the sum by the number of indicators used to obtain an average comprehensive score, which represents the percentage of the influence of the thermal storage on the gas dilution effect and the element enrichment effect, and determines the thermal storage temperature level according to its value and the set associated evaluation rules.

[0222] In the geothermal resource surface geochemical exploration system provided by the embodiment of the present invention, each module or unit structure can be operated independently or in combination according to actual setting requirements and measurement and calculation requirements to achieve corresponding technical effects.

[0223] It should be understood that the embodiments disclosed in the present invention are not limited to the specific structures, processing steps or materials disclosed herein, but should be extended to equivalent substitutions of these features understood by ordinary technicians in the relevant field. It should also be understood that the terms used herein are only used for the purpose of describing specific embodiments and are not meant to be limiting.

[0224] The "one embodiment" mentioned in the specification means that a particular feature, structure or characteristic described in conjunction with the embodiment is included in at least one embodiment of the present invention. Therefore, the phrase "one embodiment" appearing in various places throughout the specification does not necessarily refer to the same embodiment.

[0225] Although the embodiments disclosed in the present invention are as above, the above contents are only embodiments adopted for facilitating the understanding of the present invention and are not intended to limit the present invention. Any technician in the technical field to which the present invention belongs can make any modifications and changes in the form and details of the implementation without departing from the spirit and scope disclosed in the present invention, but the patent protection scope of the present invention shall still be subject to the scope defined in the attached claims.

Claims

1. A method for geothermal resource surface geochemical exploration, characterized in that: The method comprises: Sample collection steps: Determine the matching sampling grid according to the required exploration area, and then implement the collection operation to obtain samples according to the set sampling rules; Analysis and measurement steps: for different types of samples, different equipment is used to measure the gas components and elements contained in the samples according to the preset sample measurement list; the sample measurement list contains the gas components and elements to be measured corresponding to different sample types and the matching measurement equipment; Index optimization steps: Considering the influence of formation reaction, gas components and elements with migration capacity and anti-interference performance that meet the requirements are selected from the measured elements as geothermal chemical exploration indicators for different formation types; Thermal reservoir identification steps: Determine the content of soluble inorganic salts and gas in the formation, and identify the location and type of thermal reservoirs based on the set high salt and low gas areas; Thermal reservoir evaluation steps: For strata with thermal reservoirs, the cap rock score and reservoir score are calculated based on their geothermal chemical exploration indicators, and then the comprehensive score is calculated and used to achieve quantitative rating of thermal reservoir strata, combined with the corresponding thermal reservoir type output.

2. The method according to claim 1, characterized in that: In the sample collection step, the sampling rules are set including sample types and sampling methods. The sampling methods are set corresponding to the sample types. The sample types include soil samples, soil gas samples and water samples. The soil samples and soil gas samples are collected by drilling to a set depth range using matching tools.

3. The method according to claim 1, characterized in that For soil samples, the measurement equipment in the sample measurement list includes X-ray fluorescence spectrometer, inductively coupled plasma mass spectrometer, emission spectrometer, atomic fluorescence spectrometer, mercury analyzer, polarograph and ion selective electrode; For soil gas samples, the measurement equipment in the sample measurement list includes a gas chromatograph with a hydrogen flame detector, a gas chromatograph with a thermal conductivity detector, and an isotope mass spectrometer; For water samples, the measurement equipment in the sample measurement list includes inductively coupled plasma mass spectrometer and inductively coupled plasma spectrometer.

4. The method according to claim 1, characterized in that In the index optimization step, by measuring the sample helium R( 3 He / 4 He) and atmospheric helium Ra ( 3 He / 4 When the isotope ratio meets the set mantle source standard, He is preferably used as a geothermal chemical exploration indicator.

5. The method according to claim 1, characterized in that By measuring the sample CH4 carbon isotope: When it meets the set indicators, CH4 is preferred as the geothermal chemical exploration indicator; Determination of sample CO2 carbon isotope: When it meets the set inorganic origin criteria, CO2 is preferred as a geothermal chemical exploration indicator.

6. The method according to claim 1, characterized in that In the index optimization step, if the distribution degree of granite in the current formation meets the set requirements, He and Rn are not selected as geothermal chemical exploration indicators; If the minerals in the current stratum can undergo water-rock reaction to generate H2, H2 should not be selected as a geothermal chemical exploration indicator. If the current stratum belongs to the effective farmland area or the time of agricultural withdrawal is within the set time period, N, P and K elements are not selected as geothermal chemical exploration indicators; If the current stratum belongs to the seawater intrusion area or saline-alkali area, do not select K, Na, Ca, Mg, Cl, Br, and S elements; If the current stratum belongs to a rich mineral area, elements whose content in the minerals reaches the set conditions will not be selected.

7. The method according to claim 1, characterized in that In the heat reservoir identification step, the locations where both high-salt areas and low-gas areas exist and where the "high-salt" areas and the "low-gas" areas overlap are identified, and are determined to be locations where heat reservoirs exist in the underlying strata; the high-salt areas are set to have an inorganic salt content greater than or equal to the mean of the exploration area plus n times the standard deviation (n>0); the low-gas areas are set to have a gas content less than or equal to the mean of the exploration area minus n times the standard deviation (n>0).

8. The method according to claim 1, characterized in that: The heat storage identification step includes: Heat transfer channel identification steps: determine the content of elemental mercury and combined mercury in the formation, and identify the location of the heat transfer channel, heat-controlling fractures, and heat transfer direction by setting high-value bands of elemental mercury and combined mercury; Water transmission channel identification steps: determine the Na, K, and Ca contents in the formation, and identify the location of the water transmission channel, water supply fracture, and water transmission direction in combination with the set Na, K, and Ca high value bands; Steps for identifying the location of hot dry rocks: Determine the content of Nb, W, Mo, U, and Th in the formation, and identify the location of hot dry rocks by setting high-value areas of Nb, W, Mo, U, and Th; Steps for identifying the type of thermal reservoir: if there are high-salinity and low-gas areas, heat transfer channels, and water transfer channels at the same time, the thermal reservoir is identified as a hydrothermal type thermal reservoir; if there are high-salinity and low-gas areas, heat transfer channels, and areas with high values ​​of Nb, W, Mo, U, and Th, the thermal reservoir is identified as a hot dry rock type thermal reservoir; if there are high-salinity and low-gas areas, heat transfer channels, water transfer channels, and areas with high values ​​of Nb, W, Mo, U, and Th, the thermal reservoir is identified as a combined hydrothermal-hot dry rock type thermal reservoir.

9. The method according to claim 8, characterized in that In the heat transfer channel identification step, the high-value band of each indicator of elemental Hg and combined Hg is the location of the heat transfer channel. The identification standard of this band is set as the indicator content is greater than or equal to the mean value of the exploration area plus n times the standard deviation. It starts from the fault and ends at the heat reservoir. The combined highest value of elemental Hg and combined Hg is the heat-controlling fault position, and the heat transfer direction is from the heat-controlling fault to the heat reservoir.

10. The method according to claim 8, characterized in that In the water transmission channel identification step, the high-value band of Na, K, and Ca indicators is the location of the water transmission channel. The identification standard of this band is set as the indicator content is greater than or equal to the mean of the exploration area plus n times the standard deviation. It starts from the fault and ends at the heat reservoir. The combined highest value of Na, K, and Ca indicators is the water supply fault location, and the water transmission direction is from the water supply fault to the heat reservoir.

11. The method according to claim 8, characterized in that In the step of identifying the location of hot dry rocks, if there are high-value bands of each indicator, Nb, W, Mo, U, and Th, and the identification standard of this band is set to that the indicator content is greater than or equal to the mean of the exploration area plus n times the standard deviation, and the high-value band area is located within or near the set range of the high-salt and low-gas overlapping area, then the area is identified as a hot dry rock distribution area; the identification mode of hot dry rocks is "high niobium, high tungsten, high molybdenum, high uranium, and high thorium".

12. The method according to claim 1, characterized in that The thermal reservoir evaluation step includes: calculating the cap rock score of the formation according to the following formula: The reservoir score of a formation is calculated as follows: Then calculate the comprehensive score: D = D 盖 +D 储 , Where D 盖 Score for the cap layer, G i is the content of gas component, is the regional mean of gas component content; D 储 is the reservoir score, C i is the content of inorganic salt elements, is the regional mean of inorganic salt element content, and D is the comprehensive score; The comprehensive scores corresponding to multiple indicators are summed up and then divided by the number of indicators used to obtain the average comprehensive score, which represents the percentage of the influence of heat storage on gas dilution effect and element enrichment effect. The heat storage temperature level of the formation is determined based on its value and the set associated evaluation rules.

13. A geothermal resource surface geochemical exploration system, characterized in that: The system executes the method according to any one of claims 1 to 12.

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