A method and device for measuring the volume of hot dry rock

Abstract

The present invention belongs to the field of hot dry rock exploration and specifically discloses a method for measuring the volume of hot dry rocks, comprising: S1, deploying a gravity and magnetic survey network; S2, collecting gravity and magnetic data at each measuring point; S3, obtaining and gridding Bouguer gravity anomaly data and polarized magnetic anomaly data; S4, inferring and interpreting the hot dry rocks; S5, extracting the residual gravity anomaly of the hot dry rocks and calculating its integral; S6, calculating the density of the hot dry rocks and the basement surrounding rocks; S7, establishing a unit volume hot dry rock model, forward-calculating the gravity anomaly, and calculating its integral; S8, calculating the volume of the hot dry rocks. The present invention also discloses a corresponding measurement device for the above method. The present invention provides a reliable basis for the exploration, evaluation, and development of hot dry rocks. The measurement method is simple, the calculation speed is fast, the calculation results are highly reliable, and the complex gravity inversion process is avoided. The technical requirements for technicians are low, and the results are highly accurate. The present invention is suitable for measuring the volume of hot dry rocks in intermediate-acidic intrusive rocks.

Description

Technical Field

[0001] The present invention belongs to the field of hot dry rock exploration, and in particular relates to a method and device for measuring the volume of hot dry rock. Background Art

[0002] Hot dry rock refers to high-temperature rock masses with temperatures exceeding 200°C (some literature suggests 180°C or 150°C), buried thousands of meters deep, and containing no or only minimal fluids. Estimates suggest that the global continental reserves of hot dry rock are equivalent to 49.5 trillion tons of standard coal, nearly 30 times the energy reserves of all global oil, natural gas, and coal. In recent years, under the global "dual carbon goals," hot dry rock resources are expected to become a global strategic alternative energy source to fossil fuels, attracting increasing attention worldwide. This has made the exploration, development, and utilization of hot dry rock a new research hotspot.

[0003] Existing research indicates that hot dry rocks are primarily intermediate-acidic intrusive rocks developed within the sedimentary basement, primarily granite and granodiorite. Compared to the basement surrounding rocks, granite and granodiorite exhibit high magnetic susceptibility and low density, resulting in localized high magnetic fields in magnetic anomalies and low gravity fields in gravity anomalies. From the perspective of exploration effectiveness and economics, using gravity and magnetic exploration methods is the most cost-effective approach for studying hot dry rocks.

[0004] The amount of hot dry rock resources is closely related to the volume of hot dry rock. Under the same conditions, the larger the volume, the higher the heat reserve. Therefore, the volume of hot dry rock is one of the most important indicators for evaluating the amount of hot dry rock resources.

[0005] The existing technology for calculating the volume of hot dry rocks is mainly carried out through gravity inversion, which is greatly affected by factors such as the inversion method, inversion algorithm, inversion profile selection, three-dimensional modeling method, and the technical level and ability of researchers. At present, there is a lack of a method for calculating the volume of hot dry rocks that is simple and fast, has high calculation accuracy, and reliable calculation results. Summary of the Invention

[0006] The purpose of the present invention is to provide a method and device for measuring the volume of hot dry rock, so as to simply and quickly measure the volume of hot dry rock and provide basic data for the evaluation of hot dry rock resources.

[0007] In order to achieve the above-mentioned purpose, the technical methods adopted by the present invention are as follows:

[0008] A method for measuring the volume of hot dry rock comprises the following steps performed in sequence:

[0009] S1. Deploy a gravity and magnetic survey network in the hot dry rock study area;

[0010] S2. Collect gravity and magnetic data at each measuring point in the hot dry rock study area;

[0011] S3. Based on the gravity and magnetic data of each measuring point in the hot dry rock study area, obtain and grid the Bouguer gravity anomaly data and the polar magnetic anomaly data, and draw the Bouguer gravity anomaly map and the polar magnetic anomaly map;

[0012] S4, analyzing and comparing the Bouguer gravity anomaly map and the polar magnetic anomaly map obtained in step S3, performing dry hot rock inference interpretation, and delineating the distribution range of the dry hot rock body;

[0013] S5. Extracting the residual gravity anomaly of the hot dry rock based on the gridded Bouguer gravity anomaly data obtained in step S3 and the distribution range of the hot dry rock mass obtained in step S4, and then calculating the integral of the residual gravity anomaly of the hot dry rock;

[0014] S6. Collect the density values ​​of the drill cores and surface outcrops of the hot dry rock and basement surrounding rock in the hot dry rock study area and the surrounding areas, and calculate the average density values ​​of the hot dry rock and basement surrounding rock as the statistical density values ​​of the corresponding rocks;

[0015] S7. Establish a unit volume hot dry rock model based on the difference between the statistical density value of the hot dry rock obtained in step S6 and the statistical density value of the basement surrounding rock, forward calculate the gravity anomaly of the unit volume hot dry rock model, and then obtain the integral of the gravity anomaly of the unit volume hot dry rock model;

[0016] S8. The integral of the residual gravity anomaly of the hot dry rock is divided by the integral of the gravity anomaly of the hot dry rock model per unit volume. The result is the volume of the hot dry rock.

[0017] As a limitation: the deployment range of the measurement network in step S1 covers the hot dry rock mass in the study area and extends outward to the gentle background field of gravity anomalies in the hot dry rock mass.

[0018] As a limitation: the gravity and magnetic data in step S2 include the gravity value, magnetic value and coordinate elevation of the measuring point.

[0019] As a limitation: the drawing of the Bouguer gravity anomaly map in step S3 is specifically as follows: according to the gravity data of each measuring point in the hot dry rock study area, the Bouguer gravity anomaly data is obtained, and the Bouguer gravity anomaly grid data is obtained by gridding, and the Bouguer gravity anomaly map is drawn according to the Bouguer gravity anomaly grid data; the Bouguer gravity anomaly data gridding process is specifically as follows: the gravity range is used as the grid range, the gravity point distance is used as the grid distance, and the Bouguer gravity anomaly data of each measuring point in the study area is interpolated into the Bouguer gravity anomaly grid data; the drawing of the polar magnetic anomaly map is specifically as follows: according to the magnetic data of each measuring point in the hot dry rock study area, the magnetic ΔT anomaly data is obtained, and the magnetic ΔT is obtained by gridding. Abnormal grid data, the magnetic ΔT anomaly grid data is subjected to pole processing to obtain pole magnetic anomaly grid data, and the pole magnetic anomaly map is drawn based on the pole magnetic anomaly grid data; the magnetic ΔT anomaly data grid processing is specifically as follows: the range of the magnetic data is used as the grid range, the magnetic point distance is used as the grid distance, and the magnetic ΔT anomaly data of each measuring point in the study area is interpolated into magnetic ΔT anomaly grid data; the magnetic ΔT anomaly grid data pole processing is specifically as follows: the magnetic ΔT anomaly grid data is converted into pole magnetic anomaly grid data through pole processing calculation, and the pole processing calculation parameters are obtained by querying the geomagnetic parameter map or calculating through relevant software.

[0020] As a further limitation: the method for obtaining the Bouguer gravity anomaly data in step S3 is: performing Bouguer correction, terrain correction and normal field correction on the gravity value of the measuring point to obtain the Bouguer gravity anomaly data of each measuring point; the method for obtaining the magnetic ΔT anomaly data is: performing diurnal variation correction and normal field correction on the magnetic value of the measuring point to obtain the magnetic ΔT anomaly data of each measuring point.

[0021] As a limitation: the inference and interpretation of hot dry rocks in step S4 is specifically as follows: compare the high local magnetic anomaly relative to the background magnetic anomaly value on the polar magnetic anomaly map with the low local gravity anomaly relative to the background gravity anomaly value on the Bouguer gravity anomaly map; based on the characteristics of the hot dry rocks of the intermediate-acidic intrusive rock type, which have lower density than the surrounding rocks and higher magnetic susceptibility than the surrounding rocks, infer the low local gravity anomaly with the same spatial position and similar anomaly morphology as the gravity anomaly caused by hot dry rocks, and interpret the range of the above-mentioned low local gravity anomaly as the distribution range of the hot dry rock body.

[0022] As a limitation: in step S5, the specific method for extracting the hot dry rock residual gravity anomaly and calculating the integral of the hot dry rock residual gravity anomaly is as follows: using the filtering method, trend analysis method or upward continuation method to calculate the hot dry rock background gravity field using the Bouguer gravity anomaly data, subtracting the hot dry rock background gravity field from the Bouguer gravity anomaly gridded data, and then adding a gravity constant value so that the residual gravity anomaly value at the position of the hot dry rock background gravity field tends to or is equal to 0, thereby obtaining the hot dry rock residual gravity anomaly gridded data; within the hot dry rock body in the study area and extending outward to the flat background field of the hot dry rock gravity anomaly, the sum of the product of the hot dry rock residual gravity anomaly value at each grid point and the grid unit area value is the hot dry rock residual gravity anomaly integral.

[0023] As a limitation: the establishment of the unit volume hot dry rock model in step S7 is specifically as follows: the unit volume hot dry rock model adopts a cube model or a rectangular model with known length, width and height; the position of the unit volume hot dry rock model is within the distribution range of the hot dry rock body; the burial depth of the top surface of the model is greater than the predicted top surface depth of the hot dry rock; and the model density is the difference between the statistical density value of the hot dry rock and the statistical density value of the basement surrounding rock.

[0024] As a further limitation: in step S7, the gravity anomaly integral of the unit volume hot dry rock model is obtained as follows: the gravity forward calculation formula of the right cubic prism is used to perform gravity forward calculation on the unit volume hot dry rock model, the gravity forward data range is the same as the residual gravity anomaly integral calculation range, and within the gravity forward data range, the sum of the product of the gravity anomaly value of the unit volume hot dry rock model at each forward calculation point and the forward calculation grid unit area value is the gravity anomaly integral of the unit volume hot dry rock model.

[0025] The present invention also provides a device for measuring the volume of hot dry rock corresponding to the above-mentioned method for measuring the volume of hot dry rock, the device comprising:

[0026] Gravity and magnetic data acquisition module, used to collect gravity and magnetic data at each measuring point of the gravity and magnetic survey network in the study area;

[0027] The anomaly map generation module is used to process the gravity and magnetic data of each measuring point, obtain and grid the Bouguer gravity anomaly data and the polar magnetic anomaly data, and generate the Bouguer gravity anomaly map and the polar magnetic anomaly map of the study area;

[0028] The hot dry rock inference and interpretation module is used to analyze and compare the Bouguer gravity anomaly map and the polar magnetic anomaly map, infer and interpret the hot dry rock body, and delineate the distribution range of the hot dry rock body;

[0029] The module for calculating the integral amount of the residual gravity anomaly of the hot dry rock is used to extract the residual gravity anomaly of the hot dry rock and calculate the integral amount of the residual gravity anomaly of the hot dry rock;

[0030] The unit volume hot dry rock model gravity anomaly integral calculation module is used to calculate the density difference between the hot dry rock and the basement surrounding rock, establish a unit volume hot dry rock model, forward calculate the gravity anomaly of the unit volume hot dry rock model, and obtain the unit volume hot dry rock model gravity anomaly integral;

[0031] The hot dry rock volume calculation module is used to calculate the volume of the hot dry rock based on the integral amount of the residual gravity anomaly of the hot dry rock and the integral amount of the gravity anomaly of the unit volume hot dry rock model.

[0032] Due to the adoption of the above solution, the present invention has the following beneficial effects compared with the prior art:

[0033] The present invention provides a method and device for measuring the volume of hot dry rocks. The method measures the volume of hot dry rocks using gravity and magnetic exploration methods, and uses a unit volume hot dry rock model to perform gravity anomaly forward calculations, thereby providing a reliable basis for hot dry rock exploration, evaluation, and development. Compared with gravity forward and inversion methods in the prior art, the method is simple, has a fast calculation speed, and highly reliable calculation results. It avoids the complex gravity inversion process, has low technical requirements for technicians, and has high result accuracy. The accuracy of the calculation results is ensured by subtracting the background gravity field of the hot dry rock from the Bouguer gravity anomaly and making the residual gravity anomaly value at the position of the hot dry rock background gravity field approach or equal to 0. The calculation result of the residual gravity anomaly integral quantity of the present invention is only related to the residual mass of the hot dry rock relative to the surrounding rock, which makes the calculation result more stable and thus has higher reliability.

[0034] The present invention is applicable to volume calculation of intermediate-acidic intrusive hot dry rocks. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The present invention will be described in further detail below with reference to the accompanying drawings and specific embodiments.

[0036] Figure 1 This is a flow chart of a method for calculating hot dry rock according to an embodiment of the present invention;

[0037] Figure 2 This is a schematic diagram of the Bouguer gravity anomaly in the hot dry rock study area according to an embodiment of the present invention;

[0038] Figure 3 This is a schematic diagram of the magnetic ΔT anomaly in the hot dry rock study area according to an embodiment of the present invention;

[0039] Figure 4 This is a schematic diagram of the polarization magnetic anomaly in the hot dry rock study area according to an embodiment of the present invention;

[0040] Figure 5 This is a schematic diagram of the residual gravity anomaly in the hot dry rock study area according to an embodiment of the present invention;

[0041] Figure 6This is a schematic diagram of gravity anomaly per unit volume of a hot dry rock model according to an embodiment of the present invention;

[0042] Figure 7 This is a structural block diagram of a device for measuring the volume of hot dry rock according to an embodiment of the present invention. DETAILED DESCRIPTION

[0043] The present invention will be further described below with reference to the following embodiments. However, those skilled in the art should understand that the present invention is not limited to the following embodiments, and any improvements and equivalent changes made based on the specific embodiments of the present invention are within the scope of protection of the claims of the present invention.

[0044] Example: A method and device for measuring the volume of hot dry rock

[0045] Heilongjiang Province is located in the northern part of Northeast my country. It has a high geographical latitude and cold weather. The heating period is as long as 6 months a year. In the past, the main method of heating in this area was coal-burning, which not only consumed a large amount of coal resources, but also brought serious air pollution, which had a great adverse impact on local production and life. Previous geological exploration results revealed that granite bodies have developed in many underground areas in a certain area in the southern part of Heilongjiang Province. After my country vigorously carried out the exploration and development of hot dry rock clean energy, preliminary analysis showed that the granite in this area meets the identification conditions of hot dry rock, and hot dry rock geothermal resources can be developed to replace coal for local production and life. However, previous work did not study the granite in this area as a hot dry rock resource. In the recent local hot dry rock survey work, an innovative hot dry rock volume calculation method was proposed, which can quickly calculate the volume of granite and provide basic data for the evaluation of hot dry rock resources. This embodiment applies the hot dry rock volume measurement method to a certain area in the southern part of Heilongjiang Province where granite bodies have developed underground.

[0046] This embodiment provides a method for measuring the volume of hot dry rock, and its flow chart is as follows: Figure 1 As shown, the following steps are performed in sequence:

[0047] S1. Deploy a gravity and magnetic survey network in the study area. Considering that the buried depth of the hot dry rock is less than 3000m, the point and line spacing of the gravity and magnetic survey network are both 500m. The network deployment range covers the hot dry rock mass in the study area and extends outward to the gentle background field of gravity anomalies of the hot dry rock mass.

[0048] S2. Organize a construction team to carry out gravity and magnetic data collection work, and collect gravity and magnetic data at each measuring point in the hot dry rock study area. The gravity and magnetic data include the gravity value, magnetic value and coordinate elevation of the measuring point, which are obtained by measuring the gravity value, magnetic value and coordinate elevation of each measuring point using a gravimeter, magnetometer and positioning instrument respectively;

[0049] S3. According to the gravity and magnetic data of each measuring point in the hot dry rock study area, the Bouguer gravity anomaly data and magnetic ΔT anomaly data are obtained, and the Bouguer gravity anomaly grid data and magnetic ΔT anomaly grid data are obtained by gridding. The Bouguer gravity anomaly map is drawn based on the Bouguer gravity anomaly grid data, as shown in the following figure: Figure 2 As shown; the magnetic ΔT anomaly map is drawn based on the magnetic ΔT anomaly grid data, as shown Figure 3 As shown; the magnetic ΔT anomaly grid data is subjected to polarization processing to obtain polarized magnetic anomaly grid data, and the polarized magnetic anomaly map is drawn based on the polarized magnetic anomaly grid data, as shown Figure 4 As shown in the figure, the specific gridding processing of Bouguer gravity anomaly data is as follows: the range of gravity is used as the grid range, the distance between gravity points is used as the grid distance, and the Bouguer gravity anomaly data of each measuring point in the study area is interpolated into Bouguer gravity anomaly grid data; the specific gridding processing of magnetic ΔT anomaly data is as follows: the range of magnetic data is used as the grid range, the distance between magnetic points is used as the grid distance, and the magnetic ΔT anomaly data of each measuring point in the study area is interpolated into magnetic ΔT anomaly grid data; the specific polarization processing of magnetic ΔT anomaly grid data is as follows: the magnetic ΔT anomaly grid data is converted into polarized magnetic anomaly grid data through polarization processing calculation, and the polarization processing calculation parameters are obtained by querying the geomagnetic parameter map or calculating through relevant software; the method for obtaining Bouguer gravity anomaly data is as follows: the gravity values ​​of the measuring points are subjected to Bouguer correction, terrain correction and normal field correction to obtain the Bouguer gravity anomaly data of each measuring point; the method for obtaining magnetic ΔT anomaly data is as follows: the magnetic values ​​of the measuring points are subjected to diurnal variation correction and normal field correction to obtain the magnetic ΔT anomaly data of each measuring point;

[0050] S4. Analyze and compare the Bouguer gravity anomaly map and the spherical magnetic anomaly map obtained in step S3 to perform dry hot rock inference interpretation. Compare the high local magnetic anomaly on the spherical magnetic anomaly map relative to the background magnetic anomaly value with the low local gravity anomaly on the Bouguer gravity anomaly map relative to the background gravity anomaly value. Based on the characteristics of intermediate-acidic intrusive hot dry rocks, which have lower density and higher magnetic susceptibility than surrounding rocks, infer the low local gravity anomaly located in the middle of the map with the same spatial position and similar anomaly morphology as the gravity anomaly caused by the dry hot rock, and interpret the range of the low local gravity anomaly as the distribution range of the dry hot rock mass.

[0051] S5. Extract the residual gravity anomaly of the hot dry rock based on the gridded Bouguer gravity anomaly data obtained in step S3 and the distribution range of the hot dry rock mass obtained in step S4, and then calculate the integral of the residual gravity anomaly of the hot dry rock. Specifically, use the upward continuation method to extend the Bouguer gravity anomaly upward by 7 km to obtain the hot dry rock background gravity field, subtract the hot dry rock background gravity field from the gridded Bouguer gravity anomaly data, and then add a gravity constant value of 0.4×10 -5 m·s -2, so that the residual gravity anomaly value of the hot dry rock background gravity field position tends to or is equal to 0, and the hot dry rock residual gravity anomaly grid data is obtained. According to the hot dry rock residual gravity anomaly grid data, the following is obtained: Figure 5 The hot dry rock residual gravity anomaly map shown in FIG. Within the hot dry rock mass in the study area and extending outward to the gentle background field of the hot dry rock gravity anomaly, the sum of the product of the hot dry rock residual gravity anomaly value at each grid point and the grid unit area value is the hot dry rock residual gravity anomaly integral. To reduce the impact of density changes of geological bodies outside the hot dry rock mass on the calculation results, the calculation range of the hot dry rock residual gravity anomaly integral in this embodiment is within the zero value line of the hot dry rock residual gravity anomaly. The calculated hot dry rock residual gravity anomaly integral value is 51.65. The unit of gravity anomaly data is milligal, and the unit of grid unit area is km. 2 ; In addition to the upward extension method of this embodiment, the method for obtaining the background gravity field of hot dry rock can also use filtering method and trend analysis method;

[0052] S6. Collect the density values ​​of the drill cores and surface outcrops of the hot dry rock and basement surrounding rock in the hot dry rock study area and the surrounding areas, and calculate the average density values ​​of the hot dry rock and basement surrounding rock as the statistical density values ​​of the corresponding rocks. In this example, the density measurement data of the drill cores were collected, and the densities of the granite and basement surrounding rock were obtained by calculating the average density of each lithology. The statistical average density values ​​were 2.62 g / cm 3 and 2.72g / cm 3 , among which granite is the most representative rock among the intermediate-acidic intrusive dry hot rocks;

[0053] S7, based on the difference between the statistical density value of the hot dry rock obtained in step S6 and the statistical density value of the basement surrounding rock, a unit volume hot dry rock model is established, the gravity anomaly of the unit volume hot dry rock model is forward calculated, and grid processing is performed to obtain the gravity anomaly grid data of the unit volume hot dry rock model, and a gravity anomaly map of the unit volume hot dry rock model is drawn based on the gravity anomaly grid data, as shown in FIG. Figure 6 As shown, the gravity anomaly integral of the unit volume hot dry rock model is obtained; the unit volume hot dry rock model is established specifically as follows: the unit volume hot dry rock model adopts a cube model or a rectangular parallelepiped model with known length, width and height, the position of the unit volume hot dry rock model is within the distribution range of the hot dry rock mass, this embodiment adopts a cube model, the side length of the model is 1 km, the position of the model is in the middle of the distribution range of the hot dry rock mass, the top surface burial depth of the model is greater than the predicted top surface depth of the hot dry rock, the top surface burial depth of the model is 3 km, and the model density is the difference between the statistical density value of the hot dry rock and the statistical density value of the basement rock -0.1 g / cm 3In this embodiment, the gravity anomaly integral of the unit volume hot dry rock model is calculated using the gravity forward modeling formula of a right cubic prism to obtain the gravity anomaly of the unit volume hot dry rock model. In this embodiment, the gravity anomaly integral of the unit volume hot dry rock model is calculated as follows: the gravity forward modeling data range is the same as the residual gravity anomaly integral calculation range, and the forward calculation grid point spacing is 0.2 km. Within the gravity forward modeling data range, the sum of the product of the gravity anomaly value of the unit volume hot dry rock model at each forward calculation grid point and the forward calculation grid unit area value is the gravity anomaly integral of the unit volume hot dry rock model, and the grid unit area is 0.2 km × 0.2 km = 0.04 km. 2 , the calculated value of the gravity anomaly integral of the unit volume hot dry rock model is 3.11.

[0054] S8. Divide the integral of the residual gravity anomaly of the hot dry rock by the integral of the gravity anomaly of the hot dry rock model per unit volume. The result is the volume of the hot dry rock. In this embodiment, the integral of the residual gravity anomaly of the hot dry rock is 51.65, and the integral of the gravity anomaly of the hot dry rock model per unit volume is 3.11. The calculated volume of the hot dry rock is 16.71 km 3 , realizing the rapid calculation of the volume of hot dry rocks.

[0055] This embodiment also provides a hot dry rock volume measurement device corresponding to the above hot dry rock volume measurement method, and its structural block diagram is as follows: Figure 7 As shown, the device includes:

[0056] Gravity and magnetic data acquisition module, used to collect gravity and magnetic data at each measuring point of the gravity and magnetic survey network in the study area;

[0057] The anomaly map generation module is used to process the gravity and magnetic data of each measuring point, obtain and grid the Bouguer gravity anomaly data and the polar magnetic anomaly data, and generate the Bouguer gravity anomaly map and the polar magnetic anomaly map of the study area;

[0058] The hot dry rock inference and interpretation module is used to analyze and compare the Bouguer gravity anomaly map and the polar magnetic anomaly map, infer and interpret the hot dry rock body, and delineate the distribution range of the hot dry rock body;

[0059] The module for calculating the integral amount of the residual gravity anomaly of the hot dry rock is used to extract the residual gravity anomaly of the hot dry rock and calculate the integral amount of the residual gravity anomaly of the hot dry rock;

[0060] The unit volume hot dry rock model gravity anomaly integral calculation module is used to calculate the density difference between the hot dry rock and the basement surrounding rock, establish a unit volume hot dry rock model, forward calculate the gravity anomaly of the unit volume hot dry rock model, and obtain the unit volume hot dry rock model gravity anomaly integral;

[0061] The hot dry rock volume calculation module is used to calculate the volume of the hot dry rock based on the integral amount of the residual gravity anomaly of the hot dry rock and the integral amount of the gravity anomaly of the unit volume hot dry rock model.

[0062] It should be noted that the hot dry rock volume measurement device provided in the above embodiment only uses the division of the above functional modules as an example when performing data processing. In actual applications, the above functions can be assigned to different functional modules as needed.

[0063] The hot dry rock volume calculation method implemented in this invention uses the integral amount of residual gravity anomaly of hot dry rock divided by the integral amount of gravity anomaly of unit volume hot dry rock model to calculate the volume of hot dry rock. Compared with the existing technology, the volume of hot dry rock is calculated by gravity inversion technology. It is not affected by factors such as the technical level and ability of researchers, and is only related to the residual mass of hot dry rock relative to the surrounding rock. The calculation method is simple, fast and accurate, and the stability and reliability of the calculation results are higher.

Claims

1. A method for measuring the volume of hot dry rock, characterized in that: The process includes the following steps: S1. Deploy a gravity and magnetic survey network in the hot dry rock study area; S2. Collect gravity and magnetic data at each measuring point in the hot dry rock study area; S3. Based on the gravity and magnetic data of each measuring point in the hot dry rock study area, obtain and grid the Bouguer gravity anomaly data and the polar magnetic anomaly data, and draw the Bouguer gravity anomaly map and the polar magnetic anomaly map; S4, analyzing and comparing the Bouguer gravity anomaly map and the polar magnetic anomaly map obtained in step S3, performing dry hot rock inference interpretation, and delineating the distribution range of the dry hot rock body; S5. Extracting the residual gravity anomaly of the hot dry rock based on the gridded Bouguer gravity anomaly data obtained in step S3 and the distribution range of the hot dry rock mass obtained in step S4, and then calculating the integral of the residual gravity anomaly of the hot dry rock; S6. Collect the density values ​​of the drill cores and surface outcrops of the hot dry rock and basement surrounding rock in the hot dry rock study area and the surrounding areas, and calculate the average density values ​​of the hot dry rock and basement surrounding rock as the statistical density values ​​of the corresponding rocks; S7. Establish a unit volume hot dry rock model based on the difference between the statistical density value of the hot dry rock obtained in step S6 and the statistical density value of the basement surrounding rock, forward calculate the gravity anomaly of the unit volume hot dry rock model, and then obtain the integral of the gravity anomaly of the unit volume hot dry rock model; S8. The integral of the residual gravity anomaly of the hot dry rock is divided by the integral of the gravity anomaly of the hot dry rock model per unit volume. The result is the volume of the hot dry rock.

2. The method for calculating the volume of hot dry rock according to claim 1, wherein: The deployment range of the measurement network in step S1 covers the hot dry rock mass in the study area and extends outward to the gentle background field of gravity anomaly in the hot dry rock mass.

3. The method for calculating the volume of hot dry rock according to claim 1, wherein: The gravity and magnetic data in step S2 include the gravity value, magnetic value and coordinate elevation of the measuring point.

4. The method for calculating the volume of hot dry rock according to claim 1, wherein: Drawing the Bouguer gravity anomaly map in step S3 specifically comprises: obtaining Bouguer gravity anomaly data based on the gravity data of each measuring point in the hot dry rock study area, performing gridding processing to obtain Bouguer gravity anomaly gridded data, and drawing the Bouguer gravity anomaly map based on the Bouguer gravity anomaly gridded data; The specific gridding process of Bouguer gravity anomaly data is as follows: taking the gravity range as the grid range and the gravity point distance as the grid distance, the Bouguer gravity anomaly data of each measuring point in the study area are interpolated into the Bouguer gravity anomaly gridded data; The specific steps of drawing the polarized magnetic anomaly map are as follows: according to the magnetic data of each measuring point in the hot dry rock study area, the magnetic ΔT anomaly data are obtained, gridding processing is performed to obtain magnetic ΔT anomaly grid data, the magnetic ΔT anomaly grid data are polarized to obtain polarized magnetic anomaly grid data, and the polarized magnetic anomaly map is drawn based on the polarized magnetic anomaly grid data; the gridding processing of the magnetic ΔT anomaly data is specifically as follows: taking the range of the magnetic data as the grid range and the magnetic point distance as the grid distance, the magnetic ΔT anomaly data of each measuring point in the study area are interpolated into magnetic ΔT anomaly grid data; the polarization processing of the magnetic ΔT anomaly grid data is specifically as follows: the magnetic ΔT anomaly grid data are converted into polarized magnetic anomaly grid data through polarization processing calculation, and the polarization processing calculation parameters are obtained by querying the geomagnetic parameter map or calculating through relevant software.

5. A method for measuring the volume of hot dry rock according to claim 4, characterized in that: The method for obtaining the Bouguer gravity anomaly data in step S3 is as follows: performing Bouguer correction, terrain correction, and normal field correction on the gravity values ​​of the measuring points to obtain the Bouguer gravity anomaly data of each measuring point; The method for obtaining magnetic ΔT anomaly data is as follows: perform diurnal variation correction and normal field correction on the magnetic values ​​of the measuring points to obtain the magnetic ΔT anomaly data of each measuring point.

6. The method for calculating the volume of hot dry rock according to claim 1, characterized in that: The inference and interpretation of hot dry rocks in step S4 is specifically as follows: the high local magnetic anomaly relative to the background magnetic anomaly value on the polar magnetic anomaly map and the low local gravity anomaly relative to the background gravity anomaly value on the Bouguer gravity anomaly map are compared; based on the characteristics of hot dry rocks of the intermediate-acidic intrusive rock type, which have lower density and higher magnetic susceptibility than the surrounding rock, the low local gravity anomaly with the same spatial position and similar anomaly morphology is inferred to be the gravity anomaly caused by hot dry rocks, and the range of the above-mentioned low local gravity anomaly is interpreted as the distribution range of the hot dry rock body.

7. The method for measuring the volume of hot dry rock according to claim 1, characterized in that: In step S5, the specific method for extracting the hot dry rock residual gravity anomaly and calculating the integral of the hot dry rock residual gravity anomaly is as follows: using the filtering method, trend analysis method or upward continuation method to calculate the hot dry rock background gravity field using the Bouguer gravity anomaly data, subtracting the hot dry rock background gravity field from the Bouguer gravity anomaly grid data, and then adding a gravity constant value so that the residual gravity anomaly value at the location of the hot dry rock background gravity field tends to or is equal to 0, thereby obtaining the hot dry rock residual gravity anomaly grid data; within the hot dry rock mass in the study area and extending outward to the flat background field of the hot dry rock gravity anomaly, the sum of the product of the hot dry rock residual gravity anomaly value at each grid point and the grid unit area value is the hot dry rock residual gravity anomaly integral.

8. The method for calculating the volume of hot dry rock according to claim 1, wherein: The specific steps of establishing a unit volume hot dry rock model in step S7 are as follows: the unit volume hot dry rock model adopts a cube model or a rectangular parallelepiped model with known length, width and height; the position of the unit volume hot dry rock model is within the distribution range of the hot dry rock mass; the burial depth of the top surface of the model is greater than the predicted top surface depth of the hot dry rock; and the model density is the difference between the statistical density value of the hot dry rock and the statistical density value of the basement surrounding rock.

9. The method for measuring the volume of hot dry rock according to claim 8, characterized in that: The specific steps for obtaining the gravity anomaly integral of the unit volume hot dry rock model in step S7 are as follows: a gravity forward calculation formula for a right cubic prism is used to perform gravity forward calculation on the unit volume hot dry rock model; the gravity forward data range is the same as the calculation range of the residual gravity anomaly integral; within the gravity forward data range, the sum of the product of the gravity anomaly value of the unit volume hot dry rock model at each forward calculation grid point and the forward calculation grid unit area value is the gravity anomaly integral of the unit volume hot dry rock model.

10. A device for calculating the volume of hot dry rock corresponding to the method for calculating the volume of hot dry rock according to any one of claims 1 to 9, characterized in that: The device comprises: Gravity and magnetic data acquisition module, used to collect gravity and magnetic data at each measuring point of the gravity and magnetic survey network in the study area; The anomaly map generation module is used to process the gravity and magnetic data of each measuring point, obtain and grid the Bouguer gravity anomaly data and the polar magnetic anomaly data, and generate the Bouguer gravity anomaly map and the polar magnetic anomaly map of the study area; The hot dry rock inference and interpretation module is used to analyze and compare the Bouguer gravity anomaly map and the polar magnetic anomaly map, infer and interpret the hot dry rock body, and delineate the distribution range of the hot dry rock body; The module for calculating the integral amount of the residual gravity anomaly of the hot dry rock is used to extract the residual gravity anomaly of the hot dry rock and calculate the integral amount of the residual gravity anomaly of the hot dry rock; The unit volume hot dry rock model gravity anomaly integral calculation module is used to calculate the density difference between the hot dry rock and the basement surrounding rock, establish a unit volume hot dry rock model, forward calculate the gravity anomaly of the unit volume hot dry rock model, and obtain the unit volume hot dry rock model gravity anomaly integral; The hot dry rock volume calculation module is used to calculate the volume of the hot dry rock based on the integral amount of the residual gravity anomaly of the hot dry rock and the integral amount of the gravity anomaly of the unit volume hot dry rock model.

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