Method and system for identifying water-resisting layer in coal mine hydrogeology
In the hydrogeological exploration of coal mines, combining the formation profile information obtained from drilling and the consumption of circulating fluid, key sections were determined and closed water injection tests were carried out, and the problem of traditional methods was difficult to accurately identify thin aquifers, and the precise identification and thickness measurement of gravel thin layers were achieved, providing reliable technical support for coal seam mining and underground engineering.
Patent Information
- Application Number
- CN202411636238.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-15
- Publication Date
- 2025-03-28
AI Technical Summary
Traditional aquifer identification methods are difficult to achieve accurate identification of thin aquifers, especially in loose or weakly cemented formations, where there are problems of low accuracy and large error in layer determination.
By constructing exploration drilling in the research area, continuous formation profile information is obtained, and the consumption of circulating fluid is monitored during the drilling process, and the permeability of the formation is initially judged. Based on the formation profile information and permeability judgment, the key layer segments are determined, and the water injection is closed in these layer segments to measure the water consumption to identify the specific location and thickness of the thin aquifer whose permeability is greater than the preset threshold.
It realizes accurate identification of the thin layer of sand and gravel with good permeability, provides reliable parameter selection and water control scheme design, and provides important technical support for coal seam mining and underground engineering excavation.
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Figure CN119715292A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of geological exploration, and in particular to a method and system for identifying aquicludes in coal mine hydrogeology. Background Art
[0002] The accurate identification of aquicludes is an important part of the hydrogeological work in coal mines. The distribution of aquicludes in the roof and floor of coal seams is related to the optimization of coal seam mining technical parameters and water hazard prevention and control plans, especially the determination of the spatial position of aquicludes, which has an important impact on the safe mining of coal mines. In loose or weakly cemented strata, thin layers of gravel mixed in the aquicludes can easily induce abnormal water inrush and sand burst disasters during the mining of the underlying coal seams. At present, the technical methods used for the division of aquicludes mainly include coring layer determination and geophysical logging methods, among which coring layer determination is the main technical means for the division of aquicludes in geological exploration. Because loose and weakly cemented strata have not yet formed rocks, the rock structure is loose, and the drilling coring rate is very low. The error of coring layer determination is very large. When the stratum contains water or the stratum thickness encountered is small and thin interlayers appear, there is often a situation of missing layers, and the accuracy of layer determination is low. The apparent resistivity logging and natural potential logging of geophysical logging can divide the interface of rock layers in the hole and determine the location and thickness of aquifers. The curve of γ logging mainly reflects the amount of mud contained in the rock layer, and the aquifer and aquiclude can be determined accordingly. The disadvantage of this method is that it is difficult to determine aquifers with weak water richness; when the borehole water inflow is large and there are many aquifers, the measured parameters are approximate values, and the division error is large. Summary of the invention
[0003] The present invention provides a method and system for identifying an aquiclude in coal mine hydrogeology, which are used to solve the defect that the traditional aquiclude identification method is difficult to accurately identify thin aquifers.
[0004] The present invention provides a method for identifying aquicludes in coal mine hydrogeology, comprising: Drilling holes for exploration in the study area, collecting cores during the drilling process, and obtaining continuous stratigraphic profile information; monitoring the consumption of circulating fluid during the drilling process, and preliminarily determining the permeability of the formation based on the consumption of the circulating fluid in different stratigraphic sections; Determine the key layer section by combining the continuous stratigraphic profile information and the initially determined stratigraphic permeability; The key layer section is divided into multiple test sections, closed water injection is carried out in each test section, the water consumption in different test sections is measured under constant pressure, the specific location of the thin aquifer with a permeability greater than a preset threshold is identified based on the consumption, and the thickness of the thin aquifer at the corresponding location is obtained.
[0005] According to the method for identifying aquicludes in coal mine hydrogeology provided by the present invention, the stratigraphic profile information includes lithological characteristics, and the method for determining key layers by combining the continuous stratigraphic profile information and the initially determined permeability of the stratigraphic layers includes: If the lithology of a certain formation section is a gravel layer and the circulating fluid consumption is greater than a preset value, the formation section is determined to be a permeable formation section, and the permeable formation section is expanded up and down by a preset distance as a key layer section.
[0006] According to the method for identifying aquicludes in coal mine hydrogeology provided by the present invention, the water consumption in different test sections is measured under constant pressure, including: Set the initial water injection pressure P1, start the constant pressure pump, inject water into the test section, and record the start time of water injection. Record the digital flow value every preset time until the flow value tends to be stable. Record 2 valid values at each pressure level, and the difference between the two values should be less than the preset value. After the test under pressure P1 is completed, the pressure is adjusted to P2 and P3 in sequence, wherein P1 is less than P2, and P2 is less than P3, and the above steps of water injection and flow data recording are repeated. After each test section is isolated, the groundwater level in the hole of this test section is observed before the test, and the water level is observed once every preset time. When the water level drop speed is less than the preset speed for two consecutive times, the observation result is determined as the pressure calculation zero line; The injection flow rate and groundwater level change data at each pressure level are recorded, and the permeability coefficient of each test section at different pressures is calculated based on the flow data and groundwater level changes, and the consumption is obtained based on the permeability coefficient.
[0007] According to the method for identifying aquicludes in coal mine hydrogeology provided by the present invention, the specific location of the thin aquifer with a permeability greater than a preset threshold is identified according to the consumption, including: According to the results of the water pressure test, the permeability of the test section containing the impermeable layer is analyzed and calculated, and the PQ curve is drawn; Determine the PQ curve type. The permeability q of the test section is calculated using the pressure value P3 and flow value Q3 in the maximum pressure stage. The test section permeability q and PQ curve type symbols are used to represent the water pressure test results of each test section. The water-impermeability and permeability parameters of each layer are determined. The distribution position of the aquiclude is determined based on the water-impermeability and permeability parameters.
[0008] According to the method for identifying aquicludes in coal mine hydrogeology provided by the present invention, obtaining the thickness of the thin aquifer at the corresponding position includes: The specific layer distance whose permeability is greater than a preset threshold value is obtained within the distribution position range of the aquifer, and the layer distance is used as the thickness of the thin aquifer.
[0009] The present invention also provides a system for identifying aquicludes in coal mine hydrogeology, comprising: Drilling structure, in-situ permeability test device and constant pressure water injection permeability test device; The drilling structure is used to construct exploration drilling holes in the study area, collect cores during the drilling process, and obtain continuous stratigraphic profile information; monitor the consumption of circulating fluid during the drilling process, and preliminarily judge the permeability of the formation based on the consumption of the circulating fluid in different stratigraphic sections; The in-situ permeability testing device is used to determine the key layer section by combining the continuous formation profile information and the initially determined formation permeability; The constant pressure water injection permeability testing device is used to divide the key layer section into multiple test sections, perform closed water injection in each test section, measure the water consumption in different test sections under constant pressure, identify the specific location of the thin aquifer with a permeability greater than a preset threshold value based on the consumption, and obtain the thickness of the thin aquifer at the corresponding location.
[0010] According to the system for identifying aquicludes in coal mine hydrogeology provided by the present invention, the drilling structure comprises: Borehole mouth, geological casing, constant pressure water injection test section, final hole diameter, sealing plug, water injection pipeline and water injection flower pipe between plugs; The borehole opening diameter is designed to be φ133 mm, the geological casing diameter is designed to be φ219 mm, and the final hole diameter is designed to be φ113 mm.
[0011] According to the system for identifying aquicludes in coal mine hydrogeology provided by the present invention, the in-situ permeability testing device comprises: Pressure-controlled variable-frequency constant-pressure pump, used to provide stable water injection pressure; A water injection line, used to deliver water from the constant pressure pump to the test section; The plug inflation pipeline is used to fill the rubber plug with water or air to expand it and fit closely to the borehole wall; Hydraulic rubber sealing plugs are used to seal both ends of the test section.
[0012] According to the system for identifying aquicludes in coal mine hydrogeology provided by the present invention, the constant pressure water injection permeability testing device comprises: Pressure-controlled variable-frequency constant-pressure pump, used to provide stable water injection pressure; A water injection line, used to deliver water from the constant pressure pump to the test section; The plug inflation pipeline is used to fill water or air into the rubber plug to expand it and fit tightly to the borehole wall; Hydraulic rubber sealing plugs are used to seal both ends of the test section; The water injection flower tube between the plugs is used to evenly distribute the water injection points in the test section; Digital flow meter, used to monitor water injection flow in real time and record flow data during the test; Inductive water level meter, used to monitor the changes in groundwater level within the test section and record the dynamic changes of groundwater level; A controller is used to control the entire test process, including at least one of pressure regulation, water injection control and data recording.
[0013] According to the system for identifying aquicludes in coal mine hydrogeology provided by the present invention, the constant pressure water injection permeability testing device further comprises: Pressure relief valve, used to release pressure in case of overpressure; Leak detection device, used to detect whether there is leakage in the pipeline; Emergency stop button is used to ensure that the test can be stopped quickly in an emergency.
[0014] The present invention provides a method and system for identifying aquicludes in coal mine hydrogeology. The method and system obtain continuous stratigraphic profile information by constructing exploration drilling holes in the study area and collecting cores during the drilling process; monitoring the consumption of circulating fluid during the drilling process, and preliminarily judging the permeability of the formation according to the consumption of the circulating fluid in different stratigraphic sections; determining key stratigraphic sections in combination with the continuous stratigraphic profile information and the preliminarily judged permeability of the formation; dividing the key stratigraphic sections into a plurality of test sections, performing closed water injection in each test section, measuring the water consumption in different test sections under a constant pressure, identifying the specific location of the thin layer aquifer whose permeability is greater than a preset threshold value according to the consumption, and obtaining the thickness of the thin layer aquifer at the corresponding location. The present invention can accurately identify the specific location and thickness of the thin gravel layer with good permeability, and provide a reliable basis for parameter optimization and water prevention and control scheme design for underground coal mining or underground engineering excavation. BRIEF DESCRIPTION OF THE DRAWINGS
[0015] In order to more clearly illustrate the technical solutions in the present invention or the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.
[0016] Figure 1 It is a schematic flow chart of a method for identifying aquicludes in coal mine hydrogeology provided by an embodiment of the present invention; Figure 2 is a schematic diagram of the in-situ test range setting provided by an embodiment of the present invention; Figure 3 is a schematic diagram of an exploration drilling structure provided by an embodiment of the present invention; Figure 4 It is a schematic diagram of an in-situ permeability testing device provided in an embodiment of the present invention. DETAILED DESCRIPTION
[0017] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0018] Figure 1 A flowchart of a method for identifying aquicludes in coal mine hydrogeology provided by an embodiment of the present invention is shown in FIG. Figure 1 As shown, the method for identifying aquicludes in coal mine hydrogeology provided by the embodiment of the present invention includes: Step 101: constructing exploration boreholes in the study area, collecting cores during the drilling process, and obtaining continuous stratigraphic profile information; monitoring the consumption of circulating fluid during the drilling process, and preliminarily determining the permeability of the formation according to the consumption of the circulating fluid in different stratigraphic sections; Step 102, determining a key layer section by combining the continuous stratigraphic profile information and the initially determined stratigraphic permeability; Step 103: Divide the key layer section into multiple test sections, perform closed water injection in each test section, measure the water consumption in different test sections under constant pressure, identify the specific location of the thin aquifer with a permeability greater than a preset threshold value based on the consumption, and obtain the thickness of the thin aquifer at the corresponding location.
[0019] Under the conditions of underground engineering excavation and mining, the presence of aquicludes in the surrounding rock is an important factor related to the optimization of coal seam mining parameters. The thin gravel aquifer in the aquiclude poses two potential threats to the mining of the underlying coal seam: first, the thin gravel structure is loose and often has fluidity after being disturbed by mining. After the coal seam is mined, if there is a thin gravel layer within the conductive range of the mining fracture, it is very easy to induce roof sand collapse disasters, and similar accidents have occurred many times; second, the thin layer of fine sand mixed in the aquiclude, because the top and bottom plates of the sand layer are both aquicludes, the groundwater drainage conditions are not smooth, which provides a closed water storage condition for the gravel layer. The gravel layer is often pressurized and contains water. After the mining fracture is affected, it may cause sudden large-scale water inrush disasters in the mining field. Therefore, accurate identification of thin gravel aquifers in the aquiclude is an important technical work for safe mining of coal seams under such geological conditions.
[0020] The technical methods used in traditional division of aquicluded layers mainly include coring and geophysical logging, among which coring is the main technical means for division of aquicluded layers in geological exploration. Since loose and weakly cemented strata have not yet formed rocks, the rock structure is loose, and the core sampling rate is very low, the error of coring is large. When the stratum contains water or the stratum thickness encountered is small, or thin interlayers appear, there is often a situation of missing layers, and the accuracy of layer determination is low. However, the apparent resistivity logging and natural potential logging of geophysical logging can divide the rock interface in the hole and determine the position and thickness of the aquifer. The curve mainly reflects the amount of mud contained in the rock layer, and the aquicluded layer and the aquicluded layer can be determined based on this. The disadvantage of this method is that it is difficult to determine the aquicluded layer with weak permeability; when the borehole water inflow is large and there are many aquifer layers, the measured parameters are approximate values, and the division error is large.
[0021] The method for identifying aquicludes in coal mine hydrogeology provided by an embodiment of the present invention comprises the following steps: drilling holes for exploration in a study area, collecting cores during the drilling process, and obtaining continuous stratigraphic profile information; monitoring the consumption of circulating fluid during the drilling process, and preliminarily judging the permeability of the formation based on the consumption of the circulating fluid in different stratigraphic sections; determining key stratigraphic sections in combination with the continuous stratigraphic profile information and the preliminarily judged permeability of the formation; dividing the key stratigraphic sections into a plurality of test sections, performing closed water injection in each test section, measuring the water consumption in different test sections under a constant pressure, identifying the specific location of a thin layer of aquifer having a permeability greater than a preset threshold value based on the consumption, and obtaining the thickness of the thin layer of aquifer at the corresponding location. The present invention can accurately identify the specific location and thickness of a thin gravel layer with good permeability, and provide a reliable basis for parameter optimization and water prevention and control scheme design for underground engineering excavation or underlying coal seam mining.
[0022] Based on any of the above embodiments, the step of determining the key layer segment by combining the continuous stratigraphic profile information and the initially determined stratigraphic permeability includes: If the lithology of a certain formation section is a gravel layer and the circulating fluid consumption is greater than a preset value, the formation section is determined to be a permeable formation section, and the permeable formation section is expanded up and down by a preset distance as a key layer section.
[0023] For the impermeable layer section, clean water core drilling is used, and the consumption of circulating fluid is observed during the drilling process. After the hole is formed, the layer section with relatively large primary permeability is found based on the consumption observation data, such as Figure 2 As shown in the figure, the thin gravel aquifer sections A, B, and C are the target sections for constant pressure water injection observation. Since the circulating fluid consumption observation data are affected by factors such as the mud pressure in the bare hole stratum or clay aquifer exposed in the hole, the spatial position of the aquifer cannot be accurately defined. The aquifer within 10 m above and below the gravel thin layers A and C is determined as the constant pressure water injection test observation section.
[0024] Suppose that in a certain borehole, the stratigraphic profile is found to be as follows through full-hole coring: 10-20m is a clay layer, 20-30m is a gravel layer, 30-40m is a clay layer, and 40-50m is a sand layer.
[0025] At the same time, the circulating fluid consumption data shows that: 10-20m has a small consumption, 20-30m has a significantly increased consumption, 30-40m has a small consumption, and 40-50m has a medium consumption.
[0026] Combined with the above data, it can be preliminarily determined that the clay layers of 10-20m and 30-40m are the key layers. For further precision, the key layers can be expanded by 2m up and down, that is, 8-22m and 28-42m as the key test sections.
[0027] Based on any of the above embodiments, measuring the water consumption in different test sections under constant pressure includes: Set the initial water injection pressure P1, start the constant pressure pump, inject water into the test section, and record the start time of water injection. Record the digital flow value every preset time until the flow value tends to be stable. Record 2 valid values at each pressure level, and the difference between the two values should be less than the preset value. After the test under pressure P1 is completed, the pressure is adjusted to P2 and P3 in sequence, wherein P1 is less than P2, and P2 is less than P3, and the above steps of water injection and flow data recording are repeated. After each test section is isolated, the groundwater level in the hole of this test section is observed before the test, and the water level is observed once every preset time. When the water level drop speed is less than the preset speed for two consecutive times, the observation result is determined as the pressure calculation zero line; The injection flow rate and groundwater level change data at each pressure level are recorded, and the permeability coefficient of each test section at different pressures is calculated based on the flow data and groundwater level changes, and the consumption is obtained based on the permeability coefficient.
[0028] In the embodiment of the present invention, the initial thickness of the thin aquifers A, B, and C is first determined based on the core sampling layer identification and the circulating fluid consumption observation, and the starting and ending depths of the observation section are designed according to the determined test observation section range; on the basis of the thickness of the gravel thin layer and the starting and ending depths of the observation section, a double plug constant pressure water injection test is performed, and the total length of the one-time water pressure test does not exceed 2m. If the test section length exceeds 2m, it is carried out in sections; considering the characteristics of the aquiclude itself, especially the clay aquiclude, which is prone to plastic deformation under pressure, the water pressure test adopts three levels of pressure P1, P2, and P3, which are 0.3MPa, 0.6MPa, and 1.0MPa respectively. The three stages only increase but not decrease, and the pressure increase sequence is carried out according to P1→P2→P3. The leakage water value is observed once every 2 minutes at each pressure level in each test section, and 2 valid values are recorded for each pressure level. The water pressure time of each test section should generally not be less than 20min.
[0029] According to the three-level pressure of P1, P2, and P3 (0.3MPa, 0.6MPa, and 1.0MPa), a constant-pressure water injection test is carried out on each test section. The pressure is increased but not decreased in three stages. The pressure increase sequence of each test section is P1→P2→P3. The injection flow observation value is read every 2 minutes, and each level of pressure is observed twice. When the difference between the two values at the same level of pressure is less than 1L / min, it is counted as a valid value, and the pressure test of this level is considered completed, and the average value is taken as the calculated value. After the isolation of each test section is completed, the groundwater level in the hole of this test section is observed before the test, and the water level is observed every 5 minutes. When the water level drop rate is less than 5cm / min for two consecutive times, the observation work can be ended, and the final observation result is used to determine the pressure calculation zero line.
[0030] Based on any of the above embodiments, the step of identifying the specific location of the thin aquifer having a permeability greater than a preset threshold according to the consumption includes: According to the results of the water pressure test, the permeability of the test section containing the impermeable layer is analyzed and calculated, and the PQ curve is drawn; Determine the PQ curve type. The permeability q of the test section is calculated using the pressure value P3 and flow value Q3 in the maximum pressure stage. The test section permeability q and PQ curve type symbols are used to represent the water pressure test results of each test section. The water-impermeability and permeability parameters of each layer are determined. The distribution position of the aquiclude is determined based on the water-impermeability and permeability parameters.
[0031] According to the results of the water pressure test, the permeability of the test section with aquiclude is analyzed and calculated, the PQ curve is drawn, and the PQ curve type is determined. The permeability q (Lu) of the test section is calculated using the pressure value P3 and flow value (Q3) of the maximum pressure stage (third stage) according to the formula (q-test section water permeability, Lu; L-test section length, m; Q3-calculated flow rate of the third stage, L / min; P3-test section pressure of the third stage, MPa), the water permeability q of the test section and the PQ curve type symbol are used to represent the water pressure test results of each test section; if the calculated q=0.5Lu, the PQ curve type belongs to A (laminar flow) type, and the water pressure test result of the test section is 0.5 (A); according to the analysis and calculation, the water-impermeability and permeability parameters of each layer are determined, so as to accurately define the distribution position of the aquiclude.
[0032] In an embodiment of the present invention, obtaining the thickness of the thin layer of water-bearing layer at the corresponding position includes: The specific layer distance whose permeability is greater than a preset threshold value is obtained within the distribution position range of the aquifer, and the layer distance is used as the thickness of the thin aquifer.
[0033] The method for identifying aquicludes in coal mine hydrogeology provided by an embodiment of the present invention designs and constructs ground survey boreholes before coal seam mining. On the basis of full-hole coring and observation of circulating fluid consumption, the key layer section for accurate identification of thin gravel aquifers is determined according to the occurrence range of the aquiclude. Then, the developed in-situ permeability tester is installed and fixed on the drill rod, a fixed test section length is set, and rubber sealing plugs are used to seal both ends of the hole. By sealing and injecting water into the test section, the water consumption in different sections under constant pressure is measured, the permeability of each section is quantitatively tested, and the original rock permeability parameters of each section of the stratum are mastered, thereby realizing the identification of thin gravel aquifers in the aquiclude. The in-situ permeability test and precise identification of spatial position provide support for the prevention and control of roof water hazards during underground engineering excavation and mining; through formation coring and circulating fluid consumption observation methods, the distribution range of thin aquifers is analyzed, and the key layers for in-situ permeability testing are determined, which can be accurately controlled and avoid the blindness of the test range; compared with the previous aquiclude division technology, it has stronger pertinence and higher reliability, and is more suitable for the precise identification of thin gravel aquifers in the aquiclude; according to the thickness of thin aquifers in the aquiclude and the engineering accuracy requirements, the test section length and test density can be flexibly adjusted, and the test plan can be customized and optimized, taking into account both technological innovation and engineering needs.
[0034] The following is a description of the system for identifying aquicludes in coal mine hydrogeology provided by the present invention. The system for identifying aquicludes in coal mine hydrogeology described below and the method for identifying aquicludes in coal mine hydrogeology described above can be referenced to each other.
[0035] The system for identifying aquicludes in coal mine hydrogeology provided by the embodiment of the present invention comprises: Drilling structure, in-situ permeability test device and constant pressure water injection permeability test device; The drilling structure is used to construct exploration drilling holes in the study area, collect cores during the drilling process, and obtain continuous stratigraphic profile information; monitor the consumption of circulating fluid during the drilling process, and preliminarily judge the permeability of the formation based on the consumption of the circulating fluid in different stratigraphic sections; The in-situ permeability testing device is used to determine the key layer section by combining the continuous formation profile information and the initially determined formation permeability; The constant pressure water injection permeability testing device is used to divide the key layer section into multiple test sections, perform closed water injection in each test section, measure the water consumption in different test sections under constant pressure, identify the specific location of the thin aquifer with a permeability greater than a preset threshold value based on the consumption, and obtain the thickness of the thin aquifer at the corresponding location.
[0036] In the embodiment of the present invention, Figure 3 As shown, the drilling structure comprises: Borehole mouth, geological casing, constant pressure water injection test section, final hole diameter, sealing plug, water injection pipeline and water injection flower pipe between plugs; The borehole opening diameter is designed to be φ133 mm, the geological casing diameter is designed to be φ219 mm, and the final hole diameter is designed to be φ113 mm.
[0037] In the study area, the exploration boreholes for identification of thin gravel layers in the aquiclude are constructed. It is required to put geological casing into the loose strata above the aquiclude to prevent the formation above the observation section from collapsing. Taking into account the aperture number, final aperture, stability of the aquiclude, and water pressure test requirements, the test aperture of the constant pressure water injection test section is designed to be φ133mm, the diameter of the geological casing in the loose strata above the water pressure test section is designed to be φ219mm, and the final aperture is set according to the engineering requirements (such as φ113mm).
[0038] In the embodiment of the present invention, Figure 4 As shown, the in-situ permeability testing device comprises: Pressure-controlled variable-frequency constant-pressure pump, used to provide stable water injection pressure; A water injection line, used to deliver water from the constant pressure pump to the test section; The plug inflation pipeline is used to fill the rubber plug with water or air to expand it and fit closely to the borehole wall; Hydraulic rubber sealing plugs are used to seal both ends of the test section.
[0039] Water is pressed into the test section with a fixed water head. The water penetrates into the rock (clay) layer through the cracks around the hole wall of the test section. Eventually, the amount of water that penetrates tends to a stable value. According to different pressures, the corresponding flow value is measured to calculate the permeability of the formation.
[0040] In an embodiment of the present invention, the constant pressure water injection permeability testing device comprises: Pressure-controlled variable-frequency constant-pressure pump, used to provide stable water injection pressure; A water injection line, used to deliver water from the constant pressure pump to the test section; The plug inflation pipeline is used to fill water or air into the rubber plug to expand it and fit tightly to the borehole wall; Hydraulic rubber sealing plugs are used to seal both ends of the test section; The water injection flower tube between the plugs is used to evenly distribute the water injection points in the test section; Digital flow meter, used to monitor water injection flow in real time and record flow data during the test; Inductive water level meter, used to monitor the changes in groundwater level within the test section and record the dynamic changes of groundwater level; A controller is used to control the entire test process, including at least one of pressure regulation, water injection control and data recording.
[0041] According to the system for identifying aquicludes in coal mine hydrogeology provided by the present invention, the constant pressure water injection permeability testing device further comprises: Pressure relief valve, used to release pressure in case of overpressure; Leak detection device, used to detect whether there is leakage in the pipeline; Emergency stop button is used to ensure that the test can be stopped quickly in an emergency.
[0042] The constant pressure water injection permeability test device was developed and designed, including the design and development of a pressure-regulated variable frequency constant pressure pump, water injection pipeline, plug inflation pipeline, hydraulic rubber sealing plug (with an outer diameter of φ120mm), water injection flower pipes between plugs (with a combination of 0.2m, 0.5m, and 5m long and short sections), digital flow meters, inductive water level meters and other devices; the minimum length of a single test section is set at 0.2m, and the maximum can reach more than 5m, which can be flexibly adjusted according to the initial thickness of the gravel layer and the requirements of engineering accuracy.
[0043] The system for identifying aquicludes in coal mine hydrogeology provided by the present invention obtains continuous stratigraphic profile information by constructing exploration drilling holes in the study area and collecting cores during the drilling process; monitors the consumption of circulating fluid during the drilling process, and preliminarily determines the permeability of the formation according to the consumption of the circulating fluid in different stratigraphic sections; determines key stratigraphic sections in combination with the continuous stratigraphic profile information and the preliminarily determined permeability of the formation; divides the key stratigraphic sections into a plurality of test sections, performs closed water injection in each test section, measures the water consumption in different test sections under a constant pressure, identifies the specific location of the thin layer aquifer whose permeability is greater than a preset threshold value according to the consumption, and obtains the thickness of the thin layer aquifer at the corresponding location. The present invention can accurately identify the specific location and thickness of the thin gravel layer with good permeability, and provide a reliable basis for parameter optimization and water prevention and control scheme design for underground engineering excavation or underlying coal seam mining.
[0044] Through the description of the above implementation methods, those skilled in the art can clearly understand that each implementation method can be implemented by means of software plus a necessary general hardware platform, and of course, can also be implemented by hardware. Based on this understanding, the above technical solution is essentially or the part that contributes to the relevant technology can be embodied in the form of a software product, and the computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a disk, an optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiment.
[0045] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.
Claims
1. A method for identifying aquicludes in coal mine hydrogeology, characterized in that: include: Construct exploration boreholes in the study area, collect cores during the drilling process, and obtain continuous stratigraphic profile information; Monitor the consumption of circulating fluid during drilling and preliminarily judge the permeability of the formation according to the consumption of the circulating fluid in different formation sections; Determine the key layer section by combining the continuous stratigraphic profile information and the initially determined stratigraphic permeability; The key layer section is divided into multiple test sections, closed water injection is carried out in each test section, the water consumption in different test sections is measured under constant pressure, the specific location of the thin aquifer with a permeability greater than a preset threshold is identified based on the consumption, and the thickness of the thin aquifer at the corresponding location is obtained.
2. The method for identifying aquicludes in coal mine hydrogeology according to claim 1, characterized in that: The stratigraphic profile information includes lithological characteristics, and the step of combining the continuous stratigraphic profile information with the initially determined permeability of the stratigraphic formation to determine the key layer section includes: If the lithology of a certain formation section is a gravel layer and the circulating fluid consumption is greater than a preset value, the formation section is determined to be a permeable formation section, and the permeable formation section is expanded up and down by a preset distance as a key layer section.
3. The method for identifying aquicludes in coal mine hydrogeology according to claim 1, characterized in that: The method of measuring the water consumption in different test sections under constant pressure includes: Set the initial water injection pressure P1, start the constant pressure pump, inject water into the test section, and record the start time of water injection. Record the digital flow value every preset time until the flow value tends to be stable. Record 2 valid values at each pressure level, and the difference between the two values should be less than the preset value. After the test under pressure P1 is completed, the pressure is adjusted to P2 and P3 in sequence, wherein P1 is less than P2, and P2 is less than P3, and the above steps of water injection and flow data recording are repeated. After each test section is isolated, the groundwater level in the hole of this test section is observed before the test, and the water level is observed once every preset time. When the water level drop speed is less than the preset speed for two consecutive times, the observation result is determined as the pressure calculation zero line; The injection flow rate and groundwater level change data at each pressure level are recorded, and the permeability coefficient of each test section at different pressures is calculated based on the flow data and groundwater level changes, and the consumption is obtained based on the permeability coefficient.
4. The method for identifying aquicludes in coal mine hydrogeology according to claim 1, characterized in that: The step of identifying the specific location of the thin layer aquifer whose permeability is greater than a preset threshold according to the consumption includes: According to the results of the water pressure test, the permeability of the test section containing the impermeable layer is analyzed and calculated, and the PQ curve is drawn; Determine the PQ curve type. The permeability q of the test section is calculated using the pressure value P3 and flow value Q3 in the maximum pressure stage. The test section permeability q and PQ curve type symbols are used to represent the water pressure test results of each test section. The water-impermeability and permeability parameters of each layer are determined. The distribution position of the aquiclude is determined based on the water-impermeability and permeability parameters.
5. The method for identifying aquicludes in coal mine hydrogeology according to claim 1 or 2, characterized in that: The step of obtaining the thickness of the thin layer of water-bearing layer at the corresponding position comprises: The specific layer distance whose permeability is greater than a preset threshold value is obtained within the distribution position range of the aquifer, and the layer distance is used as the thickness of the thin aquifer.
6. A system for identifying aquicludes in coal mine hydrogeology, characterized in that: include: Drilling structure, in-situ permeability test device and constant pressure water injection permeability test device; The drilling structure is used to construct exploration boreholes in the study area, collect cores during the drilling process, and obtain continuous stratigraphic profile information; Monitor the consumption of circulating fluid during drilling and preliminarily judge the permeability of the formation according to the consumption of the circulating fluid in different formation sections; The in-situ permeability testing device is used to determine the key layer section by combining the continuous formation profile information and the initially determined formation permeability; The constant pressure water injection permeability testing device is used to divide the key layer section into multiple test sections, perform closed water injection in each test section, measure the water consumption in different test sections under constant pressure, identify the specific location of the thin aquifer with a permeability greater than a preset threshold value based on the consumption, and obtain the thickness of the thin aquifer at the corresponding location.
7. The system for identifying aquicludes in coal mine hydrogeology according to claim 6, characterized in that: The drilling structure comprises: Borehole mouth, geological casing, constant pressure water injection test section, final hole diameter, sealing plug, water injection pipeline and water injection flower pipe between plugs; The borehole opening diameter is designed to be φ133 mm, the geological casing diameter is designed to be φ219 mm, and the final hole diameter is designed to be φ113 mm.
8. The system for identifying aquicludes in coal mine hydrogeology according to claim 7, characterized in that: The in-situ permeability testing device comprises: Pressure-controlled variable-frequency constant-pressure pump, used to provide stable water injection pressure; A water injection line, used to deliver water from the constant pressure pump to the test section; The plug inflation pipeline is used to fill the rubber plug with water or air to expand it and fit closely to the borehole wall; Hydraulic rubber sealing plugs are used to seal both ends of the test section.
9. The system for identifying aquicludes in coal mine hydrogeology according to claim 7, characterized in that: The constant pressure water injection permeability testing device comprises: Pressure-controlled variable-frequency constant-pressure pump, used to provide stable water injection pressure; A water injection line, used to deliver water from the constant pressure pump to the test section; The plug inflation pipeline is used to fill water or air into the rubber plug to expand it and fit tightly to the borehole wall; Hydraulic rubber sealing plugs are used to seal both ends of the test section; The water injection flower tube between the plugs is used to evenly distribute the water injection points in the test section; Digital flow meter, used to monitor water injection flow in real time and record flow data during the test; Inductive water level meter, used to monitor the changes in groundwater level within the test section and record the dynamic changes of groundwater level; A controller is used to control the entire test process, including at least one of pressure regulation, water injection control and data recording.
10. The system for identifying aquicludes in coal mine hydrogeology according to claim 9, characterized in that: The constant pressure water injection permeability testing device further comprises: Pressure relief valve, used to release pressure in case of overpressure; Leak detection device, used to detect whether there is leakage in the pipeline; Emergency stop button is used to ensure that the test can be stopped quickly in an emergency.