Geochemical identification method and system for ground surface of geothermal resource fracture

Abstract

The invention provides an earth surface geochemical identification method and system for geothermal resource fracture, and the method comprises the steps: preferably selecting a plurality of geothermal fracture chemical identification indexes according to the conduction characteristics of heat in a stratum and the response attributes of elements to heat, carrying out the collection operation, obtaining a sample, processing the sample according to the sample measurement demands, and carrying out the detection of the geothermal resource fracture. Determining data of different chemical identification indexes of the sample by adopting a matched instrument; according to the types of the chemical identification indexes and the corresponding numerical value distribution condition, the type of geothermal fracture and the heat transmission direction are identified, wherein the thermal control fracture and the heat conduction fracture are included; and further calculating a temperature evaluation score of geothermal fracture based on a chemical identification index to realize grade division. By adopting the scheme, the limitation of the geothermal fracture identification technology in the prior art is overcome, the control heat fracture, the heat conduction fracture, the heat transmission channel and the heat transmission direction are identified by adopting the earth surface geochemical indexes, and the identification efficiency and accuracy are higher.

Description

Technical Field

[0001] The present invention relates to the technical field of geothermal resource surface geochemical exploration, and in particular to a surface geochemical identification method and system for geothermal resource fractures. Background Art

[0002] Geothermal resources are generally concentrated along the edges of tectonic plates, with heat sources mainly from deep earth conduction and heat generated by radioactive substances in the crust. Geothermal resources are composed of four elements: "source, connection, cover, and reservoir". "Source" refers to the heat source, "connection" refers to the channel connecting the heat source, "cover" refers to the cover layer of the heat reservoir, and "reservoir" refers to the heat reservoir.

[0003] Among the existing surface geochemical exploration technologies for geothermal resources, gas, element, and microbial geochemical exploration technologies are generally used. The main goal is to find "reservoir" elements and explore and analyze the geothermal resources of existing strata. However, the identification and evaluation of "source, connection, and cover" elements mainly rely on the results of seismic data, geophysical exploration, and geological research. That is, surface geochemical exploration technology cannot identify and evaluate the heat-controlling faults, heat-conducting faults, heat transfer channels, and heat transfer directions of geothermal resources.

[0004] 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

[0005] To solve the above problems, the present invention provides a surface geochemical identification method for geothermal resource fractures, optimizes elemental mercury, combined mercury, and shallow geothermal indicators, establishes a "mercury high temperature and high" heat transfer channel identification mode, and then identifies heat-controlling fractures, heat-conducting fractures, heat transfer channels, and heat transfer directions, and can evaluate heat storage temperature; preferably, in one embodiment, the method includes:

[0006] Indicator optimization setting steps: according to the heat conduction characteristics in the formation and the response properties of the elements to heat, multiple indicators that can identify the time and state of the heat control channel are selected and set as geothermal fracture chemical identification indicators;

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

[0008] Indicator determination steps: After processing the sample according to the sample determination requirements, the matching instrument is used to determine the data of different chemical identification indicators of the sample;

[0009] Geothermal fracture identification steps: identifying the type of geothermal fracture and the direction of heat transfer according to the type of chemical identification index and the corresponding numerical distribution; the types of geothermal fractures include heat-controlling fractures and heat-conducting fractures;

[0010] Thermal reservoir evaluation steps, calculate the temperature evaluation score of geothermal fractures based on chemical identification indicators, and classify them into grades.

[0011] In some embodiments of the present invention, in the indicator optimization setting step, elemental mercury is set as a chemical identification indicator reflecting the "present progressive" tense of thermal conduction, and combined mercury is set as a chemical identification indicator reflecting the "past perfect" tense of thermal conduction.

[0012] Furthermore, in some embodiments, in the indicator optimization setting step, shallow geothermal and / or thermophilic microorganisms are set as chemical identification indicators for identifying geothermal fractures.

[0013] Optionally, in some embodiments, in the sample collection step, the process of performing the collection operation to obtain the sample includes: collecting soil samples after drilling to a set depth range using a matching drilling tool.

[0014] In some embodiments, in the index determination step, the process of determining the mercury index data in the sample includes: drying the soil sample indoors and then crushing it, and then using a mercury meter to determine the elemental mercury content data of the crushed soil sample under a temperature environment of 50-150°C, and heating it to 150-550°C and using a mercury meter to determine the combined mercury content data of the soil sample.

[0015] Furthermore, in some embodiments, in the indicator determination step, the process of determining the shallow geothermal indicator data includes: drilling a hole using a drill according to a set depth requirement, and after removing the drill, using an infrared thermometer on site within a set time to measure the ground temperature at a corresponding depth as shallow geothermal data.

[0016] When applied, in some embodiments, the geothermal fracture identification step includes: if it is identified that there is a high-value zone between the fracture and the heat reservoir that meets the set high-value judgment condition for elemental mercury, combined mercury, shallow geothermal temperature or thermophilic microorganism indicators, and the zone starts from the fracture and ends at the heat reservoir area, then the zone is judged to be a geothermal fracture heat transmission channel, and whether it is a heat-controlling fracture or a heat-conducting fracture is judged according to the depth of the fracture; the high-value judgment condition is set as: the indicator data is greater than or equal to the regional mean plus n times the standard deviation (n>0);

[0017] If it is determined that the elemental mercury index and the shallow geothermal index both meet the set low values, and the combined mercury index meets the set high value, it is determined that there is a history of heat transfer channels in the current geology, and heat transfer is no longer occurring.

[0018] Optionally, in some embodiments, in the heat storage evaluation step, the temperature evaluation score of the geothermal fracture heat transfer channel is calculated according to the following formula:

[0019]

[0020] Where D 通 is the heat transfer channel temperature evaluation score, C i It is the measured value of elemental mercury, combined mercury, shallow ground temperature or thermophilic microorganism index. is the regional mean.

[0021] Furthermore, in some embodiments, in the thermal reservoir evaluation step, multiple indicators of the formation that meets the set mercury high temperature and high conditions are calculated and summed to obtain a comprehensive evaluation score, which is then divided by the number of indicators used to calculate an average of the comprehensive evaluation score, which represents the percentage of enhancement due to heat conduction and thermal evaporation effects compared to the background area. The thermal reservoir temperature level of the current formation is determined based on this value and the set division rules.

[0022] Based on the application aspects of the method described in any one or more of the above embodiments, the present invention also provides a surface geochemical identification system for geothermal resource fractures, which executes the method described in any one or more of the above embodiments.

[0023] Compared with the closest prior art, the present invention also has the following beneficial effects:

[0024] The present invention provides a surface geochemical identification method and system for geothermal resource fractures. The method selects multiple geothermal fracture chemical identification indicators based on the heat conduction characteristics in the formation and the response properties of the elements to heat; comprehensively considers the heat conduction characteristics in the formation and the response properties of the elements themselves, and comprehensively selects geochemical indicators that can characterize the temporal and state information of geothermal fractures;

[0025] Determine the matching grid size according to the scope of the exploration area to collect samples, and use different equipment to determine the elements of different samples; adopt a grid size that dynamically matches the scope of the exploration area to implement sample collection operations, and improve collection efficiency without affecting the accuracy of sample collection;

[0026] Then, the sample is processed according to the sample measurement requirements, and the data of different chemical identification indicators of the sample are measured using matching instruments; before measuring the indicator data value, the sample is first processed to a state that meets the measurement requirements, which helps to maintain the authenticity and reliability of the measurement data, provide accurate data support, and provide a reliable basis for subsequent judgment and calculation;

[0027] Then, the type of geothermal fracture and the direction of heat transfer are identified according to the type of chemical identification index and the corresponding numerical distribution, including heat-controlling fracture and heat-conducting fracture; the temperature evaluation score of geothermal fracture is further calculated based on the chemical identification index to achieve grade classification. With this scheme, elemental mercury, combined mercury, shallow ground temperature and their combined indicators are selected to identify geothermal fractures and heat transfer directions, with higher identification efficiency and accuracy.

[0028] 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

[0029] 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:

[0030] Figure 1 It is a schematic flow chart of a surface geochemical identification method of geothermal resource fractures provided by an embodiment of the present invention;

[0031] Figure 2 This is an example of a contour map of chemical identification indicators in the exploration area of ​​Implementation Case 1 in the surface geochemical identification method of geothermal resource fractures provided in an embodiment of the present invention;

[0032] Figure 3 This is an example of a contour map of chemical identification indicators in the exploration area of ​​Implementation Case 2 in the surface geochemical identification method of geothermal resource fractures provided in an embodiment of the present invention;

[0033] Figure 4 It is a schematic structural diagram of a surface geochemical identification system for geothermal resource fractures provided in another embodiment of the present invention. DETAILED DESCRIPTION

[0034] 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.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] Geothermal resources are generally concentrated along the edges of tectonic plates, with heat sources mainly from deep earth conduction and heat generated by radioactive substances in the crust. Geothermal resources are composed of four elements: "source, connection, cover, and reservoir". "Source" refers to the heat source, "connection" refers to the channel connecting the heat source, "cover" refers to the cover layer of the heat reservoir, and "reservoir" refers to the heat reservoir.

[0040] Among the existing surface geochemical exploration technologies for geothermal resources, gas, element, and microbial geochemical exploration technologies are generally used. The main goal is to find "reservoir" elements and explore and analyze the geothermal resources of existing strata. However, the identification and evaluation of "source, connection, and cover" elements mainly rely on the results of seismic data, geophysical exploration, and geological research. That is, surface geochemical exploration technology cannot identify and evaluate the heat-controlling faults, heat-conducting faults, heat transfer channels, and heat transfer directions of geothermal resources.

[0041] In order to solve the above problems, the present invention provides a surface geochemical identification method and system for geothermal resource fractures. The researchers of the present invention take into account that the temperature of the thermal reservoir is controlled by the thermal control fractures and the heat conduction channel. The higher the temperature of the thermal control fractures and the heat conduction channel, the more elemental mercury volatilizes and migrates to the surface, and the greater the intensity of the high-value anomaly; similarly, the higher the temperature of the thermal control fractures and the heat conduction channel, the more heat is transferred to the surface, and the higher the surface temperature. Based on this, the setting method includes the indicator optimization setting link, the sample collection link, the indicator measurement link, the geothermal fracture identification link and the thermal reservoir temperature evaluation link to optimize the elemental mercury, combined mercury, and shallow geothermal indicators, and establish a "mercury high temperature and high" heat transfer channel identification mode, thereby identifying the thermal control fractures, thermal conduction fractures, heat transfer channels, and heat transfer directions, and can accurately quantify and evaluate the thermal reservoir temperature level.

[0042] 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.

[0043] Embodiment 1

[0044] Figure 1 The schematic diagram of the process of the surface geochemical identification method of geothermal resource fractures provided in the first embodiment of the present invention is shown, referring to Figure 1 It can be seen that the method includes the following steps.

[0045] Indicator optimization setting step, according to the heat conduction characteristics in the formation and the response properties of the elements to heat, multiple indicators that can identify the time and state of the heat control channel are selected and set as geothermal fracture chemical identification indicators;

[0046] Sample collection steps: determine the matching sampling grid according to the required exploration area range, and then implement the collection operation to obtain samples;

[0047] Indicator determination steps: After processing the sample according to the set rules, the matching instrument is used to determine the data of different chemical identification indicators in the sample;

[0048] Geothermal fracture identification steps, identifying the type of geothermal fracture and heat transfer direction according to the types of chemical identification indicators and the corresponding numerical distribution;

[0049] Thermal reservoir evaluation steps, calculate the temperature evaluation score of geothermal fractures based on chemical identification indicators, and classify them into grades.

[0050] The scheme of the above-mentioned embodiment of the present invention optimizes elemental mercury, combined mercury, and shallow geothermal indicators, establishes a "mercury high temperature and high" heat transfer channel identification mode, and then identifies heat-controlling fractures, heat-conducting fractures, heat transfer channels, and heat transfer directions, and can evaluate the heat storage temperature, and has achieved good application results in two different types of geothermal field exploration areas.

[0051] Specifically, it is considered that Hg is volatile and its volatility increases with the increase of ambient temperature, and it has reducibility and can be oxidized to compound mercury.

[0052] Heat is conductive in the strata, and the heat of the underlying strata can be conducted to the surface; the elemental mercury in the strata originates from deep in the earth, and due to heat, it turns into steam and moves upward to the surface, where it is adsorbed by the soil and then gradually oxidized into mercury compounds, including HgCl, HgO, HgS, Hg2S, etc. Based on this, elemental mercury can reflect the "present continuous tense" of thermal action, and compounded mercury can reflect the "past perfect tense" of thermal action.

[0053] Geothermal faults such as controlled thermal faults are important transmission channels connecting heat sources. Such heat transmission channels are channels connecting heat reservoirs to heat sources, so heat reservoirs must be distributed near heat transmission channels.

[0054] Heat transfer channels are the dominant channels for heat conduction and gas migration, so Hg from deep sources and shallow geothermal temperatures are distributed at high values ​​on the surface. Therefore, elemental mercury, combined mercury, shallow geothermal temperatures, and their combined indicators can be selected to identify heat-controlling faults, heat-conducting faults, heat transfer channels, heat transfer directions, and evaluate heat storage temperatures.

[0055] Therefore, in an optional embodiment, in the indicator optimization setting step, elemental mercury is set as a chemical identification indicator reflecting the "present progressive" tense of thermal conduction, and combined mercury is set as a chemical identification indicator reflecting the "past perfect" tense of thermal conduction.

[0056] In actual application, it is preferred to use the three indicators of elemental mercury, combined mercury and shallow geothermal temperature for comprehensive verification to avoid the single influence of single indicator verification and improve the accuracy of judgment.

[0057] Furthermore, considering that thermophilic microorganisms have a growth advantage when the shallow ground temperature is high, the analysis of the growth conditions of thermophilic microorganisms can also be used to identify heat-controlling fractures, heat-conducting fractures, heat transfer channels, heat transfer directions, and evaluate the heat storage temperature, including thermophilic desulfurization bacteria, thermophilic anaerobic bacteria, thermophilic oil bacteria, etc.

[0058] Based on this, in some embodiments, shallow geothermal temperature and thermophilic microorganisms are set as chemical identification indicators for identifying geothermal fractures.

[0059] In actual application, it is necessary to first collect soil samples from the stratum to be tested. In an optional embodiment, in the sample collection step, the process of implementing the collection operation to obtain samples includes: using a matching drill to drill to a set depth range and then collecting soil samples.

[0060] Specifically, the sampling grid can be determined according to the scope of the exploration area, and field sample collection can be implemented. Soil samples are collected after being drilled to a certain depth using tools such as twist drills, preferably at a depth of 0.5-2m.

[0061] Further, an index determination step is performed, and after processing the sample according to the set rules, the data of different chemical identification indicators in the sample are determined using a matching instrument;

[0062] In some embodiments of the present invention, in the index determination step, the process of determining the mercury index data in the sample includes: drying the soil sample indoors and then crushing it, and then using a mercury meter to determine the elemental mercury content data of the crushed soil sample in a temperature environment of 50-150°C, and heating the soil sample to 150-550°C and using a mercury meter to determine the combined mercury content data of the soil sample.

[0063] In actual application, soil samples collected in the field are dried indoors and crushed to a certain particle size; then, a mercury meter is used to determine elemental mercury and combined mercury. The elemental mercury adsorbed by the soil is determined at 50-150°C, and then the temperature is raised to 150-550°C to determine the combined mercury in the soil.

[0064] Furthermore, in an optional embodiment, in the indicator determination step, the process of determining the shallow geothermal indicator data includes: drilling a hole using a drill according to a set depth requirement, and after removing the drill, using an infrared thermometer on site within a set time to measure the ground temperature at a corresponding depth as shallow geothermal data.

[0065] Specifically, a drilling tool may be used to drill a hole with a depth of 0.5-2.0 m. After the drilling tool is taken out, an infrared thermometer may be used in the field to quickly measure the ground temperature at a desired depth between 0.5 m and 2.0 m.

[0066] Next, the geothermal fracture identification step is initiated to identify the type of geothermal fracture and the direction of heat transfer according to the types of chemical identification indicators and the corresponding numerical distribution;

[0067] Heat-controlling faults are generally deep and large faults that connect to the source. As heat transfer channels, they are channels that connect heat reservoirs to heat sources. Heat reservoirs must be distributed near heat transfer channels. Heat transfer channels are dominant channels for heat conduction and gas migration. There are usually two ways to supply heat: directly supply heat to form heat reservoirs nearby; or supply heat to heat-conducting faults through heat conduction, and then form heat reservoirs near heat-conducting faults.

[0068] There is a heat transfer channel between the heat-controlling fracture / heat-conducting fracture and the heat reservoir, and the identification mode of the heat transfer channel is "high mercury temperature". The heat transfer direction is from the heat-controlling fracture to the heat reservoir, or from the heat-controlling fracture to the heat-conducting fracture and then to the heat reservoir.

[0069] Based on this, in a preferred embodiment, in the geothermal fracture identification step, if it is identified that there is a high-value belt between the fracture and the thermal reservoir that meets the set high-value judgment condition for elemental mercury, combined mercury, and shallow geothermal or thermophilic microbial indicators, and the belt starts from the fracture and ends at the thermal reservoir area, then the belt is judged to be a heat transfer channel, and whether it is a heat-controlling fracture or a heat-conducting fracture is determined according to the depth of the fracture; wherein, in an optional embodiment, the high-value judgment condition is set to: the indicator data is greater than or equal to the regional mean plus n times the standard deviation (n>0).

[0070] Since fractures shallower than 1000m have no effect on geothermal heat; fractures at a depth of 1000-3000m may be thermal conductive fractures; fractures that connect deep strata (as deep as the basement or upper mantle) are thermal control fractures, which are generally more than 3000m deep. Thermal conductive fractures are not connected to deep strata (heat sources) and must be connected to thermal control fractures to supply heat to the heat reservoir. Thermal conductive fractures are only channels for heat transfer. Therefore, in an optional embodiment, thermal control fractures or thermal conductive fractures can be identified based on the results of geological and geophysical exploration on the depth of fractures. There is a high-value zone between the fracture and the heat reservoir: if the depth of the identified geothermal fracture is in the range of 1000-3000m, it can be judged as a thermal conductive fracture, and the thermal conductive fracture must be connected to a fracture deeper than 3000m; if the depth of the fracture is more than 3000m, it can be judged as a thermal control fracture.

[0071] On the other hand, if it is determined that the elemental mercury index and the shallow geothermal index both meet the set low values, and the combined mercury index meets the set high value, it is determined that there is a history of heat transfer channels in the current geology, and heat transfer is no longer occurring.

[0072] In actual application, if it is identified that the elemental mercury, combined mercury and shallow geothermal indicators all show a high-value zone between the fault and the heat reservoir, and this zone starts from the fault and ends at the heat reservoir area, then this zone is judged as a heat transfer channel, and whether it is a heat-controlling fault or a heat-conducting fault is determined based on the depth of the fault; if the elemental mercury index is low, the shallow geothermal index is low, and the combined mercury index is high, it indicates that it was a heat transfer channel in geological history, but has now cooled and is no longer transferring heat.

[0073] Furthermore, the present invention can also achieve quantitative evaluation of the thermal reservoir level of thermal fracture formations, calculate the temperature evaluation score of geothermal fractures based on chemical identification indicators through the thermal reservoir evaluation step, and perform grade classification.

[0074] The temperature of the heat reservoir is controlled by heat-controlling faults and heat-conducting fault channels. The higher the temperature of heat-controlling faults and heat-conducting fault channels, the more elemental mercury volatilizes and migrates to the surface, and the greater the intensity of the high-value anomaly. Similarly, the higher the temperature of heat-controlling faults and heat-conducting channels, the more heat is conducted to the surface, and the higher the surface temperature.

[0075] For the surface geochemical anomaly area, the higher the "high mercury temperature", the higher the temperature of the heat transfer channel and the more heat is supplied. Based on this, the degree of high can be quantitatively rated.

[0076] In the thermal reservoir evaluation step, the temperature evaluation score of the geothermal fracture heat transfer channel is calculated according to the following formula:

[0077]

[0078] Where D 通 is the heat transfer channel temperature evaluation score, C i It is the measured value of elemental mercury, combined mercury, shallow ground temperature or thermophilic microorganism index. is the regional mean of the corresponding indicator data, D 通 The larger the value, the higher the temperature of the heat transfer channel, the more heat is supplied, and the higher the heat storage temperature.

[0079] Furthermore, we can calculate the sum of multiple indicators that show "high mercury temperature" and divide it by the number of indicators used to calculate value, It indicates the percentage of the degree of enhancement due to heat conduction and thermal evaporation compared with the background area, and can be used to evaluate the heat reservoir temperature. If it is calibrated with the heat reservoir temperature of a known geothermal field, the heat reservoir temperature of the same geological conditions can be evaluated.

[0080] Therefore, in an optional embodiment, in the thermal reservoir evaluation step, multiple indicators of the formation that meets the set mercury high temperature and high conditions are calculated and summed to obtain a comprehensive evaluation score, which is then divided by the number of indicators used to calculate the average of the comprehensive evaluation scores, which represents the percentage of enhancement due to heat conduction and thermal evaporation effects compared to the background area. The thermal reservoir temperature level of the current formation is determined based on this value and the set division rules.

[0081] In actual application, the geothermal resource temperature classification standard of "Geothermal Resource Geological Exploration Specification (GB / T 11615-2010)" is as follows: high temperature geothermal resources (T≥150℃), medium temperature geothermal resources (90≤T<150℃), low temperature geothermal resources (25≤T<90℃). The value range of 25-35 is evaluated as a low-temperature geothermal field; The value range of 35-45 is evaluated as medium-temperature geothermal field; A value of 45 points or more is evaluated as a high-temperature geothermal field.

[0082] 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.

[0083] Implementation case 1: Taking the geothermal surface geochemical exploration project in the Huangshadong geothermal field exploration area in Huizhou City, Guangdong Province as an example, a 216km2 geothermal surface geochemical exploration project was implemented in the Huangshadong geothermal field. 2 The sampling and analysis test of the chemical detection network. The coordinates of the four turning points in the work 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 points are deployed, 70 soil samples, 70 microbial samples, and 70 shallow temperature measurement points are deployed.

[0084] Sample collection method: Use a twist drill to collect soil samples for the determination of thermophilic microorganisms after drilling to 0.4-0.6m, and then start collecting soil samples for the determination of elemental mercury and combined mercury after drilling to 1.0-1.5m.

[0085] Mercury index determination method: After the soil sample is dried indoors, it is crushed to a set particle size. Then, an MDA-80 mercury analyzer produced by Milestone Company of Italy is used to determine the elemental mercury adsorbed in the soil at a thermal release temperature of 100°C. The mercury compounds in the soil are then determined by heating to 270°C.

[0086] Method for measuring shallow geothermal indicators: Drill a hole with a drill bit to a depth of 0.5m. After the drill bit is taken out, use an infrared thermometer to quickly measure the temperature at a depth of 0.5m; then drill to a depth of 1.0m. After the drill bit is taken out, use an infrared thermometer to quickly measure the temperature at a depth of 1.0m; take the average temperature at the depths of 0.5m and 1.0m to represent the shallow geothermal temperature.

[0087] The microbial thermophilic bacteria determination method adopts the geothermal microbial exploration method disclosed in Chinese patent CN 110760573 A to determine the distribution of thermophilic desulfurization bacteria, thermophilic anaerobic bacteria, thermophilic oleophilic bacteria, etc. in the soil.

[0088] Select elemental mercury, combined mercury, shallow ground temperature, thermophilic desulfurization bacteria and other indicators to draw contour lines, such as Figure 2As shown in the figure, it is found that there is a high-value anomaly zone between the F fault and the Huangshadong thermal-rich area for each indicator (in line with the "high mercury temperature and high" model). In practical application, the high-value zone can be set as the area where the indicator data is greater than or equal to the regional mean plus n times the standard deviation (n>0); for example, the high-value zone is ≥ the regional mean plus 0.25 times the standard deviation, and the position overlap is very high, because the F fault is not a deep and large fault, but is connected to the Tonghu fault.

[0089] Therefore, it can be judged that the F fault is a heat-conducting fault, the Tonghu fault is a heat-controlling fault, the high-value anomaly zone is a heat-conducting channel, and the heat transfer direction is from the Tonghu fault to the F fault and then to the Huangshadong heat-rich area (marked with purple hollow arrows in the figure). The application results of the present invention are consistent with the existing geothermal geological exploration results, which verifies the effect of the present invention.

[0090] Thermal reservoir evaluation method: Huangshadong geothermal field is an uplifted mountain type medium-temperature geothermal field. The cap rock in the Huangshadong thermal rich area is an effective cap rock. Exploration data have confirmed that the thermal control fault is the Tonghu fault. The thermal conductive fault is the F fault. The heat source is mainly mantle-derived heat conduction. In addition, the He isotope range of the gas sample in the soil is 0.1<R / Ra<1, which is of mixed crust-mantle origin. Therefore, there is a small amount of crust-derived radioactive heat generation. The heat transfer direction is from the Tonghu fault to the F fault and then to the Huangshadong thermal rich area. The thermal reservoir type is a combined hydrothermal and dry hot rock geothermal system.

[0091] The mean values ​​of the indicators in the Huangsha Cave Exploration Area and the mean values ​​in the heat transfer channel area were statistically analyzed and compared, and the results are shown in Table 1. Considering that shallow temperature measurement will be affected by the ambient temperature, 270°C is not the total amount of combined mercury, so this embodiment only uses elemental mercury to calculate the degree of "high mercury", and the results are shown in Table 2. The value is 36.9, which is identified as a medium-temperature geothermal resource. The water temperature of the outcrop Huilin Hot Spring is 93°C, and the bottom temperature of the Huire 1 well on the Huangshadong geothermal field is 128°C at a depth of 3009m. 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 controlled by the F thermal fault in a belt-like distribution, which is consistent with the existing geothermal geological exploration results, thereby proving the effectiveness of the method of the present invention.

[0092] Table 1 Comparison of the mean values ​​of indicators in the Huangsha Cave exploration area of ​​Huizhou City, Guangdong Province and the mean values ​​of the abnormal area

[0093] Mean Number of samples Elemental mercury (μg / kg) Combined mercury (μg / kg) Shallow ground temperature (℃) Heat transfer channel area mean 20 0.555 49.28 25.1 Average value of Huangsha Cave Exploration Area 70 0.406 28.09 23.1

[0094] Table 2. Thermal reservoir evaluation score table of Huangsha Cave Exploration Area in Huizhou City, Guangdong Province (%)

[0095] Location Number of samples <![CDATA[D 单质汞 ]]> Heat transfer channel area 20 36.9

[0096] Implementation Case 2: Taking the geothermal surface geochemical exploration project in the Shiba Basin exploration area of ​​Huizhou City, Guangdong Province as an example, a geothermal surface geochemical exploration project in the Shiba geothermal field with an area of ​​228km 2The coordinates of the four turning points of the detection network in the work area are (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), (23°27'18.81" North, 114°39'32.63" East), the sampling points are 1km×1km apart, 260 profile physical points are deployed, 260 soil samples are collected, and 260 shallow temperature measuring points are deployed.

[0097] Sample collection method: Use a twist drill to collect soil samples from 1.0-1.5m deep for the determination of elemental mercury and combined mercury.

[0098] Mercury determination method: The MDA-80 mercury analyzer produced by Milestone Company of Italy determines the elemental mercury adsorbed by the soil at a thermal release temperature of 100°C, and then raises the temperature to 270°C to determine the mercury compounds in the soil.

[0099] Shallow geothermal method: drill a hole with a drill bit to a depth of 0.5m. After the drill bit is taken out, use an infrared thermometer to quickly measure the temperature at a depth of 0.5m. Drill again to a depth of 1.0m. After the drill bit is taken out, use an infrared thermometer to quickly measure the temperature at a depth of 1.0m. The average of the temperatures at depths of 0.5m and 1.0m is taken to represent the shallow geothermal.

[0100] Select elemental mercury, combined mercury, shallow ground temperature and other indicators to draw contour lines (see Figure 3 It was found that there was a high-value anomaly zone (in line with the "high mercury temperature and high" mode) between the Heyuan Deep Fault and the Shiba No. 1, Shiba No. 2, and Shiba No. 3 heat-rich areas in each index. The high-value zone ≥ the regional mean plus 0.25 times the standard deviation, and the position overlap was very high. Therefore, it can be judged that the Heyuan Deep Fault is a heat-controlling fault, and the high-value anomaly zone is a heat conduction channel. The heat transfer direction is from the Heyuan Deep Fault to the Shiba No. 1, Shiba No. 2, and Shiba No. 3 heat-rich areas (marked with purple hollow arrows in the figure). The application results of the present invention are consistent with the existing geothermal geological exploration results, which verifies the effect of the present invention.

[0101] Thermal reservoir evaluation method: Shiba area is a sedimentary basin geothermal field. The average values ​​of the Shiba basin exploration area indicators and the average values ​​of the heat transfer channel area are statistically compared, and the results are shown in Table 3. The heat-controlling fault is the Heyuan deep fault, and the heat source is mainly mantle-sourced heat conduction. The He isotope range of the gas sample in the soil is 0.1<R / Ra<1, which is of crust-mantle mixed origin, so there is a small amount of crust-source radioactive heat generation. The heat transfer direction is from the Heyuan deep fault to Shiba No. 1 thermal rich area, Shiba No. 2 thermal rich area, and Shiba No. 3 thermal rich area. The thermal reservoir types of Shiba No. 1 thermal rich area, Shiba No. 2 thermal rich area, and Shiba No. 3 thermal rich area are hydrothermal and dry hot rock combined geothermal systems. Considering that shallow temperature measurement will be affected by ambient temperature, 270℃ is not the total amount of compounded mercury, so this embodiment only uses elemental mercury to calculate the degree of "high mercury", and the results are shown in Table 4. D 单质汞 The value is 50.2, which is judged as a high-temperature geothermal resource. Using the Huire 1 well in Huangshadong (depth 3009m, bottom temperature 128℃) for calibration, it is predicted that the heat reservoir temperatures at 3009m in Shiba No. 1 anomaly area, Shiba No. 2 anomaly area, and Shiba No. 3 anomaly area are 174℃ respectively, all of which are high-temperature geothermal resources. The comprehensive evaluation of surface geochemical indicators shows that the heat reservoir is a high-temperature geothermal resource. Existing exploration results have confirmed that the Shiba Basin exploration area is a sedimentary basin-type geothermal field. Because the thermal insulation conditions of the caprock are better than those of the Huangshadong geothermal field, it is inferred to be a high-temperature geothermal field. The heat-controlling fault is the Heyuan fault, and the heat reservoir is distributed in layers. The application results of the present invention are consistent with the existing geothermal geological exploration results, which verifies the effect of the scheme of the present invention.

[0102] The application results of the scheme of the present invention are consistent with the existing geothermal geological exploration results, which verifies the effect of the present invention.

[0103] Table 3 Comparison of the mean values ​​of the exploration area indicators in Shiba Basin, Huizhou City, Guangdong Province and the mean values ​​of the abnormal area

[0104] Mean Number of samples Elemental mercury (μg / kg) Combined mercury (μg / kg) Shallow ground temperature (℃) Heat transfer channel area mean 71 0.400 49.28 23.4 Average value of Shiba Basin exploration area 260 0.288 28.09 22.1

[0105] Table 4 Thermal reservoir evaluation score table of Shiba Basin exploration area in Huizhou City, Guangdong Province (%)

[0106] Location Number of samples <![CDATA[D 单质汞 ]]> Heat transfer channel area 71 50.2

[0107] 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.

[0108] It should be pointed out that in other embodiments of the present invention, the method can also obtain a new geothermal resource fracture identification method by combining one or several of the above embodiments to achieve accurate identification and research of geothermal resource fracture strata.

[0109] 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 surface geochemical identification method of geothermal resource fractures as described above.

[0110] 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 surface geochemical identification system for geothermal resource fractures. The system is used to perform the surface geochemical identification method for geothermal resource fractures described in any one or more embodiments. Specific embodiments are given below for detailed description.

[0111] Specifically, Figure 4 FIG. 4 is a schematic diagram showing the structure of a surface geochemical identification system for geothermal resource fractures provided in an embodiment of the present invention. Figure 4 As shown, the system includes:

[0112] An index optimization setting module is configured to select multiple indicators that can identify the time and state of the heat control channel according to the heat conduction characteristics in the formation and the response properties of the elements to the heat, and set them as geothermal fracture chemical identification indicators;

[0113] 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;

[0114] The index determination module is configured to process the sample according to the sample determination requirements and then use matching instruments to determine the data of different chemical identification indicators of the sample;

[0115] A geothermal fracture identification module, which is configured to identify the type of geothermal fracture and the direction of heat transfer according to the type of chemical identification index and the corresponding numerical distribution; the types of geothermal fractures include heat-controlling fractures and heat-conducting fractures;

[0116] The thermal reservoir evaluation module is configured to calculate the temperature evaluation score of geothermal fractures based on chemical identification indicators and classify them into grades.

[0117] In some embodiments of the present invention, the indicator optimization setting module is configured as follows:

[0118] The elemental mercury is set as the chemical identification index reflecting the "present progressive" tense of the heat conduction effect, and the combined mercury is set as the chemical identification index reflecting the "past perfect" tense of the heat conduction effect.

[0119] Furthermore, in some embodiments, the indicator optimization setting module sets shallow geothermal and / or thermophilic microorganisms as chemical identification indicators for identifying geothermal fractures.

[0120] Optionally, in some embodiments, the sample collection module is configured to perform the collection operation in the following manner: collect soil samples after drilling to a set depth range using a matching drilling tool.

[0121] In some embodiments, the index determination module determines the mercury index data in the sample by the following means: the soil sample is dried indoors and then crushed, and then a mercury meter is used to determine the elemental mercury content data of the crushed soil sample in a temperature environment of 50-150°C, and the temperature is raised to 150-550°C and a mercury meter is used to determine the combined mercury content data of the soil sample.

[0122] Furthermore, in some embodiments, the index determination module determines the shallow geothermal index data by the following means: drilling a hole using a drill bit according to a set depth requirement, and after removing the drill bit, an infrared thermometer is used on-site within a set time to measure the ground temperature at a corresponding depth as shallow geothermal data.

[0123] When applied, in some embodiments, the geothermal fracture identification module is configured as follows: if it is identified that there is a high-value zone between the fracture and the heat reservoir that meets the set conditions for elemental mercury, combined mercury, shallow geothermal temperature or thermophilic microorganism indicators, and the zone starts from the fracture and ends at the heat reservoir area, then the zone is judged to be a geothermal fracture heat transmission channel, and whether it is a heat-controlling fracture or a heat-conducting fracture is judged according to the depth of the fracture;

[0124] If it is determined that the elemental mercury index and the shallow geothermal index both meet the set low values, and the combined mercury index meets the set high value, it is determined that there is a history of heat transfer channels in the current geology, and heat transfer is no longer occurring.

[0125] Optionally, in some embodiments, the thermal storage evaluation module calculates the temperature evaluation score of the geothermal fracture heat transfer channel according to the following formula:

[0126]

[0127] Where D 通 is the heat transfer channel temperature evaluation score, C i It is the measured value of elemental mercury, combined mercury, shallow ground temperature or thermophilic microorganism index. is the regional mean.

[0128] Furthermore, in some embodiments, the thermal reservoir evaluation module is also configured to: calculate and sum multiple indicators of the formation that meets the set mercury high temperature and high conditions to obtain a comprehensive evaluation score, and then divide it by the number of indicators used to calculate an average of the comprehensive evaluation score, which represents the percentage of the degree of enhancement due to heat conduction and thermal evaporation effects compared to the background area, and determine the thermal reservoir temperature level of the current formation based on this value and the set division rules.

[0129] In the surface geochemical identification system for geothermal resource fractures provided by the embodiment of the present invention, each module or unit structure can operate independently or in combination according to actual indicator setting requirements and measurement calculation requirements to achieve corresponding technical effects.

[0130] 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.

[0131] 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.

[0132] 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 surface geochemical identification of geothermal resource fractures, characterized in that: The method comprises: Indicator optimization setting steps: according to the heat conduction characteristics in the formation and the response properties of the elements to heat, multiple indicators that can identify the time and state of the heat control channel are selected and set as geothermal fracture chemical identification indicators; Sample collection steps: determine the matching sampling grid according to the required exploration area range, and then implement the collection operation to obtain samples; Indicator determination steps: After processing the sample according to the sample determination requirements, the matching instrument is used to determine the data of different chemical identification indicators of the sample; Geothermal fracture identification steps: identifying the type of geothermal fracture and the direction of heat transfer according to the type of chemical identification index and the corresponding numerical distribution; the types of geothermal fractures include heat-controlling fractures and heat-conducting fractures; Thermal reservoir evaluation steps, calculate the temperature evaluation score of geothermal fractures based on chemical identification indicators, and classify them into grades.

2. The method according to claim 1, characterized in that In the index optimization setting step, elemental mercury is set as a chemical identification index reflecting the "present progressive" tense of heat conduction, and combined mercury is set as a chemical identification index reflecting the "past perfect" tense of heat conduction.

3. The method according to claim 1, characterized in that: In the indicator optimization setting step, shallow geothermal and / or thermophilic microorganisms are set as chemical identification indicators for identifying geothermal fractures.

4. The method according to claim 1, characterized in that: In the sample collection step, the process of implementing the collection operation to obtain samples includes: using a matching drilling tool to drill to a set depth range and then collecting soil samples.

5. The method according to claim 1, characterized in that In the index determination step, the process of determining the mercury index data in the sample includes: drying the soil sample indoors and then crushing it, and then using a mercury meter to determine the elemental mercury content data of the crushed soil sample in a temperature environment of 50-150°C, and heating it to 150-550°C to use a mercury meter to determine the combined mercury content data of the soil sample.

6. The method according to claim 1, characterized in that In the index determination step, the process of determining the shallow geothermal index data includes: drilling a hole with a drill according to the set depth requirement, after removing the drill, using an infrared thermometer on site within a set time to measure the ground temperature at the corresponding depth as the shallow geothermal data.

7. The method according to claim 1, characterized in that In the geothermal fracture identification step, if it is determined that there is a high-value zone between the fracture and the heat reservoir that meets the set high-value judgment condition for elemental mercury, combined mercury, shallow geothermal or thermophilic microorganism indicators, and the zone starts from the fracture and ends at the heat reservoir area, then the zone is judged to be a geothermal fracture heat transmission channel, and whether it is a heat-controlling fracture or a heat-conducting fracture is judged according to the depth of the fracture; wherein the high-value judgment condition is set as: the indicator data is greater than or equal to the regional mean plus n times the standard deviation (n>0); If it is determined that the elemental mercury index and the shallow geothermal index both meet the set low values, and the combined mercury index meets the set high value, it is determined that there is a history of heat transfer channels in the current geology, and heat transfer is no longer occurring.

8. The method according to claim 1, characterized in that In the thermal reservoir evaluation step, the temperature evaluation score of the geothermal fracture heat transfer channel is calculated according to the following formula: Where D 通 is the heat transfer channel temperature evaluation score, C i It is the measured value of elemental mercury, combined mercury, shallow ground temperature or thermophilic microorganism index. is the regional mean.

9. The method according to claim 1, characterized in that: The comprehensive evaluation score is obtained by calculating and summing up multiple indicators of the formation that meets the set mercury high temperature and high conditions, and then divided by the number of indicators used to calculate the average comprehensive evaluation score, which represents the percentage of the degree of enhancement due to heat conduction and thermal evaporation effects compared with the background area. Based on this value and the set division rules, the thermal reservoir temperature level of the current formation is determined.

10. A surface geochemical identification system for geothermal resource fractures, characterized in that: The system executes the method according to any one of claims 1 to 9.

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