Carbonate rock area deep karst water circulation identification method based on multiple levels

Abstract

The invention discloses a carbonate rock region deep karst water circulation identification method based on multiple levels, and relates to the technical field of image processing. Comprising the following steps: S1, based on the lithology and form of a rock core and in combination with drilling construction conditions, preliminarily identifying the position of a fracture-cavity body in a reservoir; s2, on the basis of a physical exploration method, in combination with the position of the fracture-cavity body, identifying the distribution and space size of the fracture-cavity body; the physical exploration method comprises a wide-area electromagnetic method, an EH4 method, a high-density resistivity method and a two-dimensional seismic method; s3, determining a migration channel of deep karst water based on a tracer experiment in combination with a local rainfall condition; and S4, based on the distribution and the space size of the fractured-vuggy body, the deep karst water circulation can be identified in combination with the water transportation channel. According to the method, based on core-physical exploration-hydrochemistry three-field coupling, judgment indexes of deep karst water circulation are established, and the accuracy is high.

Description

Technical Field

[0001] The present application relates to the field of geological exploration technology, and in particular to a multi-layered method for identifying deep karst water circulation in carbonate rock areas. Background Art

[0002] Deep karst refers to a type of karst that is not controlled by an erosional base level and is primarily found within the deep slow-flow zones of reservoirs. As a unique karst phenomenon, deep karst represents a spatial manifestation of karst development. In the era of relatively limited drilling and engineering, this phenomenon remained largely unrecognized. It was not until the 1950s, when drilling and engineering projects reached relatively deep depths, that this phenomenon began to be recognized. Existing data indicates that deep karst and the resulting caves are widespread. Currently, the world's largest deep cave is located in the Alma River basin in southern Europe, with depths ranging from 800 to 1,331 meters below ground level and a height of 531 meters. Deep caves have been discovered on the Yunnan-Guizhou Plateau in southwestern Guizhou, with a 1.6-meter-high cave over 2,580 meters below ground level, equivalent to 1,070 meters below sea level. The largest sub-river cave discovered is at Wujiangdu in northern Guizhou, where a cave over 9 meters high rises 227 meters below the riverbed.

[0003] Paleokarst refers to karst that formed during geological history rather than under modern climate conditions and is buried beneath young sediments. The development of paleokarst caves is related to ancient exposure. Generally speaking, many researchers conflate deep karst with paleokarst. However, according to current widespread understanding, some deep karst is not buried after its formation due to geological history, but rather is a modern deep cave that is still developing. For example, the deep cave directly excavated from the Yuanliangshan Tunnel in Chongqing has a filling dating of 20 ka, indicating modern deep karst. However, existing technologies do not have a method to accurately identify deep karst. Summary of the Invention

[0004] In order to solve at least one of the above problems, the present application provides a multi-level method for identifying deep karst water circulation in carbonate rock areas.

[0005] To achieve the above objectives, the present application provides a multi-layered method for identifying deep karst water circulation in carbonate rock areas, comprising the following steps:

[0006] S1. Based on the lithology and morphology of the core and the drilling operation conditions, preliminary identification of the reservoir fracture and cave layers is carried out;

[0007] S2. Identify the distribution and spatial size of fracture-cavity bodies based on physical exploration methods, taking into account the layers where the fracture-cavity bodies are located; the physical exploration methods include wide-area electromagnetic method, EH4 method, high-density resistivity method and 2D seismic method;

[0008] S3. Based on tracer experiments and combined with local precipitation conditions, clarify the migration pathways of deep karst water;

[0009] S4. Based on the distribution and spatial size of fracture-cavern bodies and combined with water migration channels, the deep karst water circulation can be identified.

[0010] One embodiment of the present invention is that S1 includes the following sub-steps:

[0011] Core sampling is carried out in target areas at different depths;

[0012] Determine the karst morphology and lithology of the core;

[0013] Based on the karst morphology and lithology, combined with the venting conditions during drilling construction, the strata where the fractures and caves are located are preliminarily identified.

[0014] An embodiment of the present invention is that the karst morphology of the core includes cracks, pores and caves.

[0015] Furthermore, the method for preliminary identification of the layer where the fracture-cavity body is located is as follows: if the hollowing phenomenon occurs during the drilling process, it indicates that there are caves in the layer section; if the core of the layer section has a large number of dissolved pores or caves, it indicates that the layer section belongs to a strongly developed karst pore section; if the core of the layer section has a large number of cracks, it indicates that the fracture network is developed in the layer section.

[0016] One embodiment of the present invention is that the wide-area electromagnetic method detects geoelectric information at different depths by sending and receiving signals of different frequencies; the EH4 method observes four mutually perpendicular horizontal components of the natural alternating electromagnetic field on the ground; the high-density resistivity method observes and studies the laws of artificial conduction current field anomalies caused by resistivity differences in the surrounding rocks of the geological target area by deploying a large number of electrodes on the survey line, thereby surveying the geological structure; the two-dimensional seismic method artificially excites seismic waves on the survey line, receives reflected waves from the underground interface through a detector, and obtains a two-dimensional seismic time profile or depth profile graphic reflecting the underground geological structure after processing.

[0017] One embodiment of the present invention is that S3 includes the following sub-steps: injecting a tracer at a fixed point, monitoring the concentration of the tracer at other points, and determining the migration channel of deep karst water based on the tracer concentration: the earlier the tracer concentration peak at the monitoring point appears and the more sinusoidal the concentration change curve is with time, the larger the deep karst water migration channel between the monitoring point and the fixed point; and setting multiple fixed points in sequence, and determining the migration channel of deep karst water based on the change in tracer concentration between the multiple points.

[0018] One embodiment of the present invention is that between S3 and S4, the following steps are further included: based on hydrochemical experiments and combined with local precipitation, the migration of deep karst water between multiple points is verified. Further, this operation includes the following sub-steps: for fixed points in the reservoir or on the ground, the hydrochemical conditions of the produced water at these fixed points under different time conditions are detected by hydrochemical experiments, the correlation of each ion in the water is calculated, and the karst water migration channels between the multiple fixed points are analyzed in combination with local precipitation under different time conditions: based on the correlation of anions and cations in the water, the main influencing minerals of deep karst groundwater can be determined; based on the rise and fall of ion levels in the fixed points of the reservoir and combined with local precipitation, the relationship between the fixed points and the surface precipitation can be determined; based on the ion correlation of the fixed points in the reservoir, deuterium and oxygen-18 detection results, the karst water circulation between the fixed points and the relationship between the fixed points and the surface precipitation can be determined.

[0019] The beneficial effect of the present invention is that the method of the present invention establishes a judgment index for deep circulation based on the coupling of core-physical exploration-hydrochemistry three fields, and its accuracy is relatively high. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a photo of part of the core from the Huandi 1 well;

[0021] Figure 2 This is a photo of part of the core from the Huandi 4 well;

[0022] Figure 3 This is a diagram of the deployment of wide-area electromagnetic methods;

[0023] Figure 4 This is the deployment diagram of the EH4 method and high-density resistivity method;

[0024] Figure 5 : is the tracer concentration curve of this embodiment changing with time;

[0025] Figure 6 is the Gibbs diagram of this embodiment. DETAILED DESCRIPTION

[0026] The following will clearly describe the technical solutions of this application in conjunction with the embodiments of this application. Obviously, the embodiments described are part of the embodiments of this application, not all of them. Based on the embodiments of this application, other embodiments obtained by ordinary technicians in this field without making any creative work are all within the scope of protection of this application.

[0027] The present application provides a multi-layered method for identifying deep karst water circulation in carbonate rock areas, comprising the following steps:

[0028] S1. Based on the lithology and morphology of the core and the drilling operation conditions, preliminary identification of the reservoir fracture and cave layers is carried out;

[0029] In this step, core samples are first taken from the target area at different depths. There are many methods for core sampling, but this step does not require consideration of the oil and gas distribution within the core. Therefore, the most conventional sampling method is sufficient, eliminating the need for more complex methods such as pressure coring. In this example, coring is performed using wells in the Huanjiang area as an example, with the primary coring wells being Huandi 1 and Huandi 4.

[0030] After sampling, the core's karst morphology and lithology need to be analyzed. The so-called karst morphology of the core refers to the different manifestations of the core's internal structure after karstification. For example, the core without karstification is basically intact, with few or no microcracks and no large pores. However, the core with karstification may have more microcracks, small dissolved pores, or even larger caves inside and even on the side walls. Cores with severe karstification may have characteristics such as rock fragmentation or rock network cracking. In such cases, the karst situation of these cores is relatively serious.

[0031] At the same time, coring requires drilling, so we can further study it based on the drilling operation conditions: if the drilling process causes emptying, it indicates that the layer has developed caves; if the core of this layer contains a large number of dissolved pores or caves, it indicates that the layer is a section with strong karst pore and cave development; if the core of this layer contains a large number of cracks, it indicates that the layer has a well-developed fracture network. Of course, there are other situations. For example, the core of this layer contains a large amount of mud fillings in the caves and cracks, which indicates that these layers may be the result of surface mud seeping down along the cracks, or it may be mud brought into the formation after ancient dissolution.

[0032] As for lithology, it refers to the composition of the rock, such as dolomite, gray dolomite, etc., which are conventional carbonate rocks. Carbonate rocks are easily dissolved, so it can be preliminarily determined that there may be dissolution in this layer.

[0033] According to the above operations and combined with the sampling depth of the core, a rough judgment can be made on the fractures and caves and the layers prone to dissolution.

[0034] In this embodiment, the core sampling photos of different layers in Huandi Well 1 and Huandi Well 4 are as follows: Figure 1 and Figure 2As shown in the figure, the karst morphologies in Well Huandi 1 and Well Huandi 4 include the following: a) dolomite sandification, b) fleshy dissolution, c) needle-shaped dissolution pores, d) honeycomb-shaped dissolution pores, e) pores, f) large-scale dissolution caves, g) rock fragmentation, h) rock web cracking, i) rock patchiness, j) rock brecciation, k) rock mylonitization, and l) growth of thick pure calcite veins in fractures. At the same time, in addition to the karst morphology, according to the analysis of the core, the dissolution area also has different filling growth forms: a. Calcified growth, in some cave sections, chemical and mud mixed growth lines can be seen, and the cave may be related to the surface hydrological system; b. Lace-like growth lines, multi-stage growth of calcite can be identified in some holes, but the growth direction and growth environment of each stage are different; c. One-stage chemical filling of the holes, the holes are filled with calcite or dolomite; d. Mud filling of the cave, mud filling can be seen at 230m, 432m, 880m and even 1132m, which is far below the local discharge base level or sea level, indicating that it may be surface mud seepage along the cracks.

[0035] S2. Identify the distribution and spatial size of fracture-cavity bodies based on physical exploration methods, taking into account the layers where the fracture-cavity bodies are located; the physical exploration methods include wide-area electromagnetic method, EH4 method, high-density resistivity method and 2D seismic method;

[0036] In this step, building on the previous step, physical exploration methods are used to further identify the distribution and size of fractures and caverns. Wide-area electromagnetic (WAM), EH4, high-density resistivity, and 2D seismic are common methods in this field and are relatively inexpensive compared to 3D seismic.

[0037] The wide-area electromagnetic method detects geoelectrical information at different depths by transmitting and receiving signals of different frequencies. In this step, its features are as follows: Only a single component of the electromagnetic field (primarily the electrical component) needs to be measured. By iteratively calculating the wide-area apparent resistivity, it can operate simultaneously in both the "distant zone" and the non-"distant zone," thereby expanding the measurement range and increasing the detection depth. Simultaneously transmitting multiple frequencies using pseudo-random signals can greatly improve observation efficiency and enhance anti-interference capabilities. Since only a single component is observed and multiple signals can be received simultaneously, the workload is greatly reduced, work efficiency is improved, and it is suitable for operation in complex terrain areas. In this embodiment, the wide-area electromagnetic instrument can measure signals comprising 12 frequency groups totaling 80 frequencies, with a frequency range of 5 / 512 to 8192 Hz. Its operating deployment conditions are as follows: two survey lines are laid out. Line L1 is centered on the ZK1 well, with a survey line angle of N14°E, a length of 1 km, a point spacing of 25 m, and 40 measurement points. Line L2 crosses the Yifeng syncline and Tangchao anticline. The survey line angle is 61°E north, the length is 17 km, the point spacing is 100 m, and 163 measuring points are arranged. Figure 3 shown.

[0038] The EH4 method observes four mutually perpendicular horizontal components of the natural alternating electromagnetic field on the ground. The characteristics of this method are: using natural field sources for observation, there is no near-field effect or transition zone effect; the instrument is lightweight and suitable for mountainous areas with developed terrain and vegetation; the observation frequency band is between 0.1Hz and 100KHz, with a minimum depth of a few meters and a maximum depth of 2000m; tensor and vector observations can be performed, and the response to two-dimensional structures is relatively realistic, reflecting geological laws more realistically; the work efficiency is high, and it can still work efficiently in places with very poor terrain conditions, and the cost is low; it is not restricted by communication conditions; and the final result is simple to calculate. In this embodiment, the working deployment conditions are as follows: divided into 3 lines and 5 lines. The detection point distance of this audio magnetotelluric method is 10m, and a total of 100 physical points have been detected, and the electrical structure characteristics within 800m can be detected, such as Figure 4 The red line part is shown.

[0039] The high-density resistivity method is to observe and study the laws of artificial conduction current field anomalies caused by resistivity differences in the surrounding rocks of the geological target area by laying a large number of electrodes on the survey line, and then to survey the geological structure. It is characterized by high density. In this embodiment, its working deployment conditions are as follows: the detection point distance is 10m, and two lines L3 and L5 are collected. The length of L3 line is 1000m, and the length of L5 line is 590m. It can detect and obtain electrical structural characteristics within 100m, and complete the detection of 180 physical points in total. Figure 4 shown.

[0040] The 2D seismic method artificially excites seismic waves along a survey line, receives reflected waves from underground interfaces via geophones, and processes them to produce a 2D seismic time profile or depth profile that reflects the underground geological structure. In this example, six 2D survey lines deployed by the Oil and Gas Resources Survey Center of the China Geological Survey were used, covering a total length of 110 km.

[0041] S3. A tracer is injected into a fixed point and the concentration of the tracer at other points is monitored. The migration channel of deep karst water can be determined based on the change pattern of the tracer concentration: the earlier the tracer concentration peak appears at the monitoring point and the concentration change curve is sinusoidal, the larger the deep karst water migration channel between the monitoring point and the fixed point; multiple fixed points are set in sequence, and the migration channel of deep karst water can be determined based on the change of tracer concentration between multiple points.

[0042] In this step, after placing a tracer at a certain fixed point, if tracers with decreasing concentrations are detected at multiple different monitoring sites, it means that these monitoring sites are connected to the fixed point in sequence, and they belong to the migration channel of deep karst water; if the concentrations detected at multiple different monitoring sites are similar, it means that these monitoring sites may be connected to the fixed point at the same time. Then, the fixed point is changed, and the above operation is repeated. The above preliminary conclusions are verified and corrected, and finally the migration channel of deep karst water between multiple points is obtained. Figure 5 shown.

[0043] After conducting the tracer test, the migration of deep karst water between multiple points can also be verified based on hydrochemical experiments and local precipitation. The method includes the following steps: using hydrochemical experiments to detect the hydrochemical conditions of produced water at fixed points in the reservoir or on the ground under different time conditions, calculating the correlation of various ions in the water, and analyzing the karst water migration channels between multiple fixed points in combination with local precipitation under different time conditions: based on the correlation of anions and cations in the water, the main influencing minerals of deep karst groundwater can be determined; based on the rise and fall of ion levels in fixed points in the reservoir and local precipitation, the relationship between the fixed points and surface precipitation can be determined; based on the ion correlation, deuterium and oxygen-18 detection results at fixed points in the reservoir, the karst water circulation between fixed points and the relationship between the fixed points and surface precipitation can be determined.

[0044] In this example, water samples were collected from 21 typical karst springs and boreholes HD1-2 and HD1-4 at fixed depths within the Huanjiang deep karst research area for 12 consecutive months from January to December. Hydrochemical and deuterium-oxygen isotope analyses were performed. The statistical results for the annual water samples are shown in Table 1, with the unit being mg / L.

[0045] Table 1 Statistics of water chemical parameters

[0046]

[0047]

[0048] From the perspective of annual changes, the TDS value range is 185.595-505.90 mg / L. The seasonal variation of TDS of borehole water samples is more obvious. Among them, the TDS of boreholes HD1-4 in July and August is significantly higher; the TDS of spring points is relatively stable. Among them, the TDS variation range of the typical karst spring HS010 is 185.595-226.3 mg / L, and the seasonal variation is not obvious, reflecting that the groundwater in the karst area is affected by the combined influence of water mixing and atmospheric precipitation in different periods.

[0049] The coefficient of variation of water ion concentration reflects the degree of data dispersion and, to a certain extent, the temporal and spatial differentiation characteristics of ions. + >K + >Mg 2+ >Ca 2+ The anion variation coefficient showed that HCO3 - >Cl - >SO4 2- >NO3 - , revealing that Na + and HCO3 - The variation is large, which causes the Na + and HCO3 - The higher variability is largely due to its seasonal changes and the resulting differences in water-rock interactions.

[0050] The annual variations in major ion and anion concentrations at different depths in different boreholes show that the surface water from borehole HD1-2, HD1-2-630, and spring HS010 exhibit similar concentrations and exhibit similar temporal trends, primarily showing relative stability from January to July, a sudden change in August, and a return to normal levels from September to November. This suggests a close hydraulic connection between borehole HD1-2 and spring HS010. The surface water from borehole HD1-4 exhibits similar concentrations of major ions to the water at a fixed depth of 230 m, with similar temporal trends. However, the chemical composition of these two waters differs significantly from that of the water at a fixed depth of 430 m. From February to April and from October to November, the major hydrochemical compositions of HD1-4-430, HD1-4-230, and the surface water from the borehole exhibit opposite trends. This suggests significant differences in the recharge sources and runoff processes of groundwater at different depths within borehole HD1-4.

[0051] The results of principal component analysis showed that the ions that contributed most to the water chemistry in the study area were Ca 2+ 、Na + 、CO3 2- 、SO4 2- , where the dominant cation is Ca 2+ , the dominant anion is CO3 2- Since the lithology of the study area is mainly carbonate rock, the chemical composition of groundwater is significantly affected by the interaction between water and rock. In order to further determine the controlling factors of the water chemical composition of deep karst water bodies, the TDS and cation ratio Na of the water samples were analyzed. + / (Na + +Ca 2+ ) and anion ratio Cl - / (Cl -+HCO3 - ) is calculated and the obtained data is analyzed by Gibbs diagram, such as Figure 6 The Na / (Na+Ca) ratio ranged primarily from 0.006 to 0.4, and the Cl / (Cl+HCO3) ratio ranged primarily from 0.001 to 0.35. The water characteristics of the vast majority of sampling points fell within the rock weathering type range. A small number of water bodies were at the interface between the evaporation-concentration type and the rock weathering type, with the influence of evaporation-concentration and precipitation being less pronounced. Only the water sample HD1-4-430, obtained in March, fell within the evaporation-concentration type range. This suggests that part of the water supply to HD1-4-430 in March came from atmospheric precipitation that evaporated and then underwent long-term leaching and concentration.

[0052] The deuterium and oxygen isotope test results of the water samples from Huandi Well 1, Huandi Well 4, and the karst water points near the boreholes are listed in Table 2. 18 The O value ranged from -6.95‰ to -8.05‰, with an average of -7.45‰, and showed a decreasing trend with increasing depth. The δD value ranged from -44.7‰ to -53.8‰, with an average of -48.79‰, and showed a decreasing trend with increasing depth. The δ 18 The O value ranges from -7.03‰ to -7.44‰, with an average value of -7.275‰, and shows a decreasing trend with increasing depth; the δD value ranges from -44.4‰ to -48.4‰, with an average value of -46.88‰, and shows an increasing trend with increasing depth; the δ 18 The O value ranges from -6.36‰ to -8.8‰, with an average value of -7.31‰, and the δD value ranges from -35.4‰ to -59.1‰, with an average value of -46.26‰. 18 The O and δD values ​​are both more negative than those in Well Huandi 4, indicating that the groundwater in the borehole of Well Huandi 1 is less affected by evaporation than that in Well Huandi 1.

[0053] Table 2 δD, δ 18 OTest results

[0054]

[0055] From δD and δ 18 The O relationship diagram shows that the distribution areas and trends of Ring 1 well water, Ring 4 well water and spring water are different. Except for the abnormal points, all water points are concentrated near the global atmospheric precipitation line (Global atmospheric precipitation line GMWL: δD=8*δ 18O+10, Craig, 1961), but the water in Huandi 1 well is evenly distributed along the atmospheric precipitation line, and the water points in Huandi 4 well are mostly distributed in the upper left of the atmospheric precipitation line and are relatively concentrated, with only one water point distributed in the lower right; the spring water points are scattered in the upper left of the atmospheric precipitation line and most of them are far away from the atmospheric precipitation line.

[0056] δD and δ of the water points at the four wells around the ground 18 The O value is distributed above the atmospheric precipitation line, indicating that the groundwater in the Huandi 4 borehole comes from atmospheric precipitation. Water points are evenly scattered on both sides of the evaporation line, showing a strong evaporation effect. The only two groundwater points revealed by the borehole are located to the lower right of the evaporation line and the atmospheric precipitation line and far away from the evaporation line. 18 O is relatively light, showing the characteristics of ancient water.

[0057] Compared with Ring 1 and Ring 4, most springs are located above the atmospheric precipitation line and δD and δ 18 The O values ​​are all positive, indicating that the spring water originates from modern atmospheric precipitation and is subject to strong evaporation. HS010 falls on the evaporation line, indicating that Ring Land 1 and HS010 have a close hydraulic connection.

[0058] S4. Based on the distribution and spatial size of fracture-cavern bodies and combined with water migration channels, the deep karst water circulation can be identified.

[0059] Through the above methods, it can be seen that the deep karst groundwater in Huanjiang area has the same origin as spring water and atmospheric precipitation, which shows that the deep karst groundwater in Huanjiang area originated from contemporary atmospheric precipitation and continuously interacts with the surrounding rocks under the long-term alternation of surface and groundwater bodies, controlling the development of modern karst in deep strata.

[0060] It will be understood that the present application is not limited to the precise construction that has been described above and shown in the accompanying drawings, and that various modifications and changes may be made without departing from the scope thereof, the true scope being indicated by the present application.

Claims

1. A multi-layered method for identifying deep karst water circulation in carbonate rock areas, characterized in that: The following steps are involved: S1. Based on the lithology and morphology of the core and the drilling operation conditions, preliminary identification of the reservoir fracture and cave layers is carried out; S2. Identify the distribution and spatial size of fracture-cavity bodies based on physical exploration methods, taking into account the layers where the fracture-cavity bodies are located; the physical exploration methods include wide-area electromagnetic method, EH4 method, high-density resistivity method and 2D seismic method; S3. Based on tracer experiments and combined with local precipitation conditions, clarify the migration pathways of deep karst water; S4. Based on the distribution and spatial size of fracture-cavern bodies and combined with water migration channels, the deep karst water circulation can be identified.

2. The method according to claim 1, characterized in that S1 includes the following steps: Core sampling is carried out in target areas at different depths; Determine the karst morphology and lithology of the core; Based on the karst morphology and lithology, combined with the venting conditions during drilling construction, the strata where the fractures and caves are located are preliminarily identified.

3. The method according to claim 1 or 2, characterized in that The karst morphology of the core includes cracks, pores and caves.

4. The method according to claim 3, characterized in that The method for preliminary identification of the layer where the fracture-cavity body is located is as follows: if the hollowing phenomenon occurs during the drilling process, it indicates that there are caves in the layer; if the core of the layer has a large number of dissolved pores or caves, it indicates that the layer belongs to the layer with strong karst pore development; if the core of the layer has a large number of cracks, it indicates that the fracture network is developed in the layer.

5. The method according to claim 1, wherein The wide-area electromagnetic method detects geoelectric information at different depths by sending and receiving signals of different frequencies; the EH4 method observes four mutually perpendicular horizontal components of the natural alternating electromagnetic field on the ground; the high-density resistivity method observes and studies the laws of anomalies in the artificially conducted current field caused by differences in the resistivity of the surrounding rock in the geological target area by laying a large number of electrodes on the survey line, thereby surveying the geological structure; the two-dimensional seismic method artificially excites seismic waves on the survey line, receives reflected waves from the underground interface through a detector, and obtains a two-dimensional seismic time profile or depth profile reflecting the underground geological structure through processing.

6. The method according to claim 1, characterized in that The step S3 includes the following sub-steps: injecting a tracer at a fixed point, monitoring the tracer concentration at other points, and determining the migration channel of deep karst water based on the variation pattern of the tracer concentration: the earlier the tracer concentration peak at the monitoring point appears and the more sinusoidal the concentration variation curve over time, the larger the deep karst water migration channel between the monitoring point and the fixed point; and setting multiple fixed points in sequence, and determining the migration channel of deep karst water based on the variation of the tracer concentration between the multiple points.

7. The method according to claim 1, characterized in that Between S3 and S4, the following steps are also included: based on water chemical experiments and combined with local precipitation, the migration of deep karst water between multiple points is verified.

8. The method according to claim 7, characterized in that Based on hydrochemical experiments and combined with local precipitation, the operation of verifying the deep karst water migration between multiple points includes the following steps: for fixed points in the reservoir or on the ground, hydrochemical experiments are used to detect the hydrochemical conditions of the produced water at these fixed points under different time conditions, and the correlation of each ion in the water is calculated. Combined with the local precipitation under different time conditions, the karst water migration channels between multiple fixed points are analyzed: based on the correlation between anions and cations in the water, the main influencing minerals of deep karst groundwater can be determined; based on the rise and fall of ion levels in fixed points in the reservoir and combined with local precipitation, the relationship between the fixed point and the surface precipitation can be determined; based on the ion correlation, deuterium and oxygen-18 detection results at fixed points in the reservoir, the karst water circulation between fixed points and the relationship between the fixed point and the surface precipitation can be determined.

Images