A water pressure drop range and water drainage time prediction method applied to downhole porous water drainage

Abstract

The present application relates to the technical field of coal mine floor aquifer drainage and pressure reduction, and particularly relates to a water pressure drop range and drainage time prediction method applied to underground porous water drainage. The method comprises the following steps: delineating a water-rich abnormal area by multiple means; obtaining the target area's water conductivity and elastic water release coefficient based on group-hole water drainage test data; arranging control points around the working face, especially at places where the aquiclude is relatively thin, calculating the apparent water inrush coefficient and determining the design water level drawdown; combining the water conductivity, elastic water release coefficient of each aquifer and the control point's design water level drawdown to predict the drainage time; reasonably arranging drainage holes in the water-rich abnormal area and establishing an underground multi-hole water drainage system; and further dynamically regulating the water drainage system operation by using the control point's design water level drawdown and drainage time. The present application can predict the drainage time in advance, optimize the construction schedule and improve the overall work efficiency.

Description

Technical Field

[0001] This invention relates to the field of water drainage and pressure reduction technology for aquifers in coal mine floor strata, specifically to a method for predicting water pressure drop and drainage time in underground multi-hole drainage systems. Background Technology

[0002] Mine water hazards are one of the most serious disasters in coal mining. As the depth of coal seam mining increases, the water pressure in the aquifer gradually increases, and the hydrogeological conditions become increasingly complex, making the problem of deep, high-pressure water hazards increasingly prominent. Therefore, it is essential to take effective water hazard prevention measures to reduce the pressure head of the floor and ensure that the water pressure at the working face is below the safe pressure.

[0003] Traditional downhole drainage systems primarily rely on single-hole or simple multi-hole drainage designs. These systems are typically inefficient in controlling water pressure and cannot accurately predict water pressure changes and drainage time. Furthermore, existing technologies are inadequate in real-time monitoring and data processing of water pressure changes, leading to an inability to adjust drainage strategies in a timely manner and thus increasing construction risks. Summary of the Invention

[0004] To address the aforementioned technical problems, the present invention aims to provide a method for predicting water pressure drop and drainage time in downhole multi-hole drainage systems. The specific technical solution adopted is as follows:

[0005] One embodiment of the present invention provides a method for predicting water pressure drop and drainage time in downhole multi-hole drainage systems, the method comprising:

[0006] Step S1: Delineate the water-rich anomaly zone using multiple methods; obtain the hydraulic conductivity and elastic release coefficient of the target area based on the data from the multi-hole water release test;

[0007] Step S2: Set up control points around the working face, especially where the waterproof layer is thin, calculate the apparent water inrush coefficient and determine the design drawdown.

[0008] Step S3: Predict the dredging time by combining the hydraulic conductivity, elastic release coefficient and design drawdown of each aquifer;

[0009] Step S4: Based on the water-rich anomaly zone, reasonably arrange drainage holes and establish a downhole multi-hole water release system; further apply the design water level drawdown and drainage time of the control points to dynamically regulate the operation of the water release system.

[0010] Preferably, the water-rich anomaly zone is delineated, including:

[0011] Geological surveys, geophysical exploration, and remote sensing technologies were used to delineate water-rich anomaly zones.

[0012] Preferably, the hydraulic conductivity and elastic release coefficient of each aquifer in the target area are obtained using a multi-well discharge test, including:

[0013] The hydraulic conductivity and elastic release coefficient of each aquifer in the target area were obtained by using a multi-hole discharge test.

[0014] Preferably, calculating the apparent water inrush coefficient of the control point includes:

[0015] The apparent water inrush coefficient of a control point is the ratio of the water head pressure borne by the water-resistant layer of the coal seam floor at the control point to the effective thickness of the water-resistant layer.

[0016] Preferably, the design drawdown of the control point is:

[0017]

[0018] Among them, s i This represents the design drawdown at the i-th control point; T represents the apparent water inrush coefficient at the i-th control point; s M represents the critical inrush coefficient; i This represents the effective water-resistant layer thickness of the coal seam floor at the i-th control point.

[0019] Preferably, the dredging time of the control point is predicted based on the hydraulic conductivity, elastic release coefficient, and design drawdown of each aquifer, including:

[0020] Calculate the total hydraulic conductivity of the target area based on the hydraulic conductivity of each aquifer; calculate the total elastic water release coefficient of the target area based on the elastic water release coefficient of each aquifer.

[0021] Based on the total hydraulic conductivity and total elastic release coefficient of the target area, an equation for calculating the descent time is established. The equation for calculating the descent time of the control point is as follows:

[0022]

[0023] Among them, s i represents the design drawdown at the i-th control point; n represents the number of drainage orifices; r j t represents the distance between the j-th dredging hole and the i-th control point; i The descent time at the i-th control point is represented by y; y represents the integral variable.

[0024] The descent time of the control point is obtained by solving the equation for the descent time.

[0025] Preferably, the downhole multi-hole water discharge system includes:

[0026] The downhole multi-hole water discharge system includes a multi-hole water discharge device, a water pressure and flow monitoring device, and a surface control and data processing device; wherein, the multi-hole water discharge device includes a drain hole, a water discharge pipe and a water discharge valve, and the water pressure and flow monitoring device includes a capacitive sensor and an electromagnetic flow meter.

[0027] The embodiments of the present invention have at least the following beneficial effects: The present invention delineates water-rich anomaly zones; by using a multi-well drainage test, the hydraulic conductivity and elastic release coefficient of each aquifer in the target area are obtained; through the comprehensive application of geological survey, geophysical exploration and remote sensing technology, the shortcomings of a single method can be made up for, and the accuracy and reliability of the delineation results can be improved; the multi-well drainage test can simulate the hydrogeological conditions in the actual mining process, and provide more practically meaningful data; through the coordinated test of multiple well sites, hydrogeological parameters at different locations in the area can be obtained, and the characteristics of the aquifer can be fully understood;

[0028] Furthermore, control points are set up, and the design drawdown of the control points is calculated by using the apparent water inrush coefficient of the control points. Then, the drawdown time of the control points is predicted by combining the hydraulic conductivity and elastic release coefficient of each aquifer. This helps to predict the drainage and pressure reduction time in advance, which helps to reasonably arrange the construction schedule and improve the overall work efficiency.

[0029] Finally, a multi-hole drainage system was established in the well. The drainage of water was controlled by the multi-hole drainage system according to the design drawdown and drainage time of the control points. This helps to systematically manage the water pressure drop of each control point in the well, monitor and control the water pressure and flow changes of each drainage hole in real time, and ensure the drainage and pressure reduction effect. Attached Figure Description

[0030] To more clearly illustrate the technical solutions and advantages in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 A flowchart of a method for predicting water pressure drop and drainage time in downhole multi-hole drainage provided by an embodiment of the present invention;

[0032] Figure 2 A delineation map of anomaly zones in coal mines, provided by an embodiment of the present invention, for predicting water pressure drop and drainage time in underground multi-hole drainage systems;

[0033] Figure 3 This is a diagram showing the layout of drainage holes for a method to predict water pressure drop and drainage time in a downhole multi-hole drainage system, as provided in an embodiment of the present invention. Detailed Implementation

[0034] To further illustrate the technical means and effects adopted by the present invention to achieve its intended purpose, the following, in conjunction with the accompanying drawings and preferred embodiments, details the specific implementation, structure, features, and effects of a method for predicting water pressure drop and drainage time in downhole multi-hole drainage systems according to the present invention. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0035] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0036] The following description, in conjunction with the accompanying drawings, details a specific scheme for predicting water pressure drop and drainage time in downhole multi-hole drainage systems provided by this invention.

[0037] Example:

[0038] The main application scenarios of this invention are as follows: This application delineates water-rich anomaly areas, obtains hydrogeological parameters through large-flow multi-hole drainage tests, calculates the water pressure drop at control points, and predicts the drainage and pressure reduction time at control points; then, a multi-hole drainage system is established based on the water pressure drop and drainage and pressure reduction time at control points for drainage. Its core advantage lies in its ability to effectively improve drainage and pressure reduction efficiency, which is of great significance for improving coal seam floor water hazard prevention technology and reducing the cost of water hazard prevention engineering.

[0039] Please see Figure 1 The diagram illustrates a flowchart of a method for predicting water pressure drop and drainage time in downhole multi-hole drainage, provided by an embodiment of the present invention. The method includes the following steps:

[0040] Step S1: Delineate the water-rich anomaly zone; use a multi-hole water release test to obtain the hydraulic conductivity and elastic release coefficient of each aquifer in the target area.

[0041] When draining water from a coal mine, it is necessary to identify areas of high water abundance to guide the placement of drainage holes. These areas need to be delineated using a combination of methods.

[0042] Geological surveys, geophysical exploration, and remote sensing technologies were used to delineate water-rich anomaly zones.

[0043] (1) Geological survey method, including lithological analysis, structural analysis and topographic analysis. It was found that the distance between the Cambrian limestone aquifer and the coal seam is between 28.06 and 87.92 m, the water pressure is between 1.78 and 2.71 MPa, and the apparent water inrush coefficient is between 0.024 and 0.077 MPa / m. The Cambrian limestone aquifer poses a threat during mining.

[0044] (2) Geophysical exploration method: On the surface, controlled source audio-frequency magnetotelluric sounding and transient electromagnetic method are used to conduct geophysical exploration of the working face to find water and explore the water-rich anomaly zone 10m, 50m and 80m below the Cambrian limestone of the coal seam floor; underground, transient electromagnetic exploration is used to delineate the water-rich area.

[0045] (3) Using satellite remote sensing images, information such as surface temperature, vegetation cover, and water distribution was analyzed to indirectly infer the enrichment of groundwater. The results showed that the target area was a piedmont alluvial plain with a terrain that was high in the north and low in the south, and gullies were well-developed. Part of the atmospheric precipitation was collected in the gullies as surface runoff and flowed out of the well field from north to south; the other part infiltrated the ground and flowed along the gaps in the alluvial deposits, and was discharged as springs at the cutting points of the gullies or in the Jinghe River valley. In summary, using a combination of methods, based on the different locations of the water-rich areas in the upper Cambrian limestone, 38 water-rich anomaly areas were divided, such as Figure 2 As shown.

[0046] Furthermore, after delineating the water-rich anomaly zone, it is necessary to obtain the hydrogeological parameters of the target area. Using a multi-well drainage test, the hydraulic conductivity and elastic release coefficient of each aquifer in the target area are obtained. Specifically, a predetermined number of hydrological wells are designed and constructed for downhole multi-well drainage tests, including two drop-flow tests. The total flow rate for the first drop-flow test is 350 m³ / h. 3 / h, the total discharge flow rate of the second stage is 450 m³ / h. 3 / h, preferably, in this embodiment of the invention, the number of hydrological holes is 10. The implementer can determine the number of hydrological holes according to the actual situation. When conducting a water release test, the number of drop heights needs to be determined according to the actual situation.

[0047] The multi-hole water release test is conducted downhole, and the equipment includes boreholes and valves. Common equipment includes filters, flow meters (or weirs), water level gauges, thermometers, timers, etc.

[0048] During the group well water discharge test, the hydrological wells are divided into observation wells and drainage wells. The water pressure and flow rate of the observation wells and drainage wells are observed simultaneously. The observation interval is first close and then sparse. The measurements are taken every 1 minute from the 1st to the 10th minute after the start of the test, every 2 minutes from the 10th to the 20th minute, every 10 minutes from the 20th to the 120th minute, and then every 30 minutes thereafter.

[0049] A large-scale multi-well water release test conducted downhole determined the hydraulic conductivity of the first aquifer to be 64.729 m. 2 / d, the hydraulic conductivity of the second aquifer is 65.875m. 2 / d. The elastic water release coefficient of the first aquifer is 0.000425, and that of the second aquifer is 0.000211. Simultaneously, the borehole drainage coefficient of the target area was obtained as 35.199 min / m. 2 This indicates that the limestone aquifer at the bottom of the coal seam is easily released.

[0050] Step S2: Arrange control points around the working face and where the waterproof layer is thin, and calculate the apparent water inrush coefficient of the control points; obtain the design drawdown of the control points based on the apparent water inrush coefficient.

[0051] During coal mining, stress changes in the goaf can cause damage to the coal seam floor, forming a floor disturbance failure zone. The depth of the floor disturbance failure zone directly affects the water pressure requirements of the confined aquifer. The deeper the floor disturbance failure zone, the greater the water pressure needs to be reduced to ensure that water does not seep into the coal mining area through the failure zone.

[0052] Furthermore, control points are arranged around the working face and in areas where the waterproof layer is thin, and the apparent water inrush coefficient of the control points is calculated. The water pressure drop of the control points is designed based on the apparent water inrush coefficient dropping below the safe value.

[0053] The design of the drawdown at control points should use the apparent water inrush coefficient as an important reference for judging the design drawdown depth. Specifically, control points should be arranged around the proposed working face and in areas where the impermeable layer is thin, as shown in the distribution diagram. Figure 3 As shown, A, B, C, D, E, F, G, and H are the control points to be arranged. The design drawdown of the control points is calculated according to the following formula:

[0054]

[0055] Among them, s i This represents the design drawdown at the i-th control point; T represents the apparent water inrush coefficient at the i-th control point; s M represents the critical inrush coefficient; i T represents the effective water-resistant layer thickness of the coal seam floor at the i-th control point. s The critical water inrush coefficient is set at 0.06 MPa / m in sections where the base plate is structurally damaged, and at 0.1 MPa / m in sections where the aquitard is intact and without structural damage.

[0056] The apparent water inrush coefficient of the i-th control point is the ratio of the water head pressure borne by the water-resistant layer of the coal seam floor at the i-th control point to the effective thickness of the water-resistant layer of the coal seam floor at the i-th control point. The specific calculation formula is as follows:

[0057]

[0058] in, M represents the apparent water inrush coefficient at the i-th control point; i P represents the effective water-resistant layer thickness of the coal seam floor at the i-th control point; i This represents the water head pressure borne by the water-blocking layer of the coal seam floor at the i-th control point.

[0059] The empirical formula for the effective water-resistant layer thickness of the coal seam floor at the control point is: M i =M 0i -max(0.7007+0.1079L, 0.303L) 0.8 ), where M 0i Let L be the thickness of the aquitard layer on the bottom of the coal seam at the i-th control point; max(0.7007+0.1079L, 0.303L) 0.8 ) represents the depth of the base plate disturbance and damage, L represents the working face width, and 1m water column = 0.00981Mpa.

[0060] like Figure 3 As shown, in this invention, the working face widths of 12010, 12030, and 12050 are 220m, 200m, and 150m respectively. Using max(0.7007+0.1079L, 0.303L)... 0.8 The calculated depths of the disturbance and failure zones on the coal seam floor are 23.34m, 21.28m, and 16.68m, respectively.

[0061] Considering the coal seam depth and the thickness of the floor waterproofing layer, control points are selected around the working face. The maximum value of L is calculated using the formula: max(0.7007+0.1079L, 0.303L). 0.8 The depth of the disturbance and failure zone of the coal seam floor was calculated to be between 14.88 and 23.34 m, with an average of 19.02 m.

[0062] With the target of an apparent water inrush coefficient not exceeding 0.06 MPa / m, control points were set up around the working face. The design drawdown of each control point is shown in Table 1.

[0063] Table 1 Design of Water Pressure Drop at Control Points

[0064]

[0065] At this point, the design drawdown for each control point is obtained.

[0066] Step S3: Predict the dredging time of the control point based on the hydraulic conductivity, elastic release coefficient and design drawdown of each aquifer.

[0067] Next, the Theis formula for unsteady flow is used, and the fsolve function in Python is employed to numerically solve for the depressurization time of the group of wells, obtaining a numerical solution to predict the depressurization time of the control points. In this embodiment of the invention, the aquifer is divided into two layers, namely the first aquifer and the second aquifer. In step S1, the hydraulic conductivity and elastic release coefficient of the first and second aquifers in the target area are obtained. It should be noted that the number of aquifer layers is determined based on the actual geological conditions on site. In this embodiment of the invention, two aquifer layers are used as an example for illustration. In actual implementation, the number of aquifer layers needs to be determined according to the on-site geological conditions.

[0068] Based on the hydraulic conductivity and elastic release coefficient of the first and second aquifers, and combined with Theis's formula, the descent time of each control point under the condition of multiple wells releasing water is calculated.

[0069] First, the total hydraulic conductivity of the target area is calculated based on the hydraulic conductivity of the first and second aquifers. The total hydraulic conductivity of the target area is the weighted sum of the hydraulic conductivity of each aquifer, calculated using the following formula:

[0070] T total =b1T1+b2T2,

[0071] Where T1 and T2 represent the hydraulic conductivity of the first and second aquifers, respectively; b1 and b2 represent the first and second weighting coefficients, respectively. Substituting T1 = 64.729 and T2 = 65.875, we obtain the total hydraulic conductivity T. total It is 65.302m 2 / d, the first and second weight coefficients are both 0.5, and implementers can adjust them according to the actual situation.

[0072] Next, the total elastic water release coefficient of the target area is calculated based on the elastic water release coefficients of the first and second aquifers. The calculation method for the total elastic water release coefficient of the target area is the same as that for the total hydraulic conductivity, and it is a weighted sum of the elastic water release coefficients of each aquifer. The calculation formula is as follows:

[0073]

[0074] in, and denoted as the elastic water release coefficients of the first and second aquifers, respectively; a1 and a2 are the third and fourth weighting coefficients, respectively. and The values ​​are 0.000425 and 0.000211 respectively, and the values ​​of a1 and a2 are both 0.5. Then the total elastic water release coefficient is 0.000318.

[0075] Furthermore, based on the Theis formula for unsteady flow, a solution equation for the settling time is constructed by combining the total hydraulic conductivity and the total elastic release coefficient.

[0076] According to Theis's formula for unsteady flow, the drawdown of the discharge orifice at any point (observation orifice) in a single-orifice discharge test is:

[0077]

[0078] Where s represents the drawdown at any point (observation well), and W(u) represents the well function.

[0079] According to the superposition principle, the total drawdown at any control point caused by the release of water from multiple wells is: The equation for solving the descent time is:

[0080]

[0081] Among them, s i represents the design drawdown at the i-th control point; n represents the number of drainage orifices; r j t represents the distance between the j-th dredging hole and the i-th control point; i y represents the time it takes for the water pressure at the i-th control point to reach a safe level, which is also the dredging time at the i-th control point; y represents the integral variable.

[0082] Since Theis's formula includes an exponential integral function W(u), it cannot be solved analytically directly. Therefore, the Python "fsolve" function is used to numerically solve the evacuation time equation. The time it takes for the water pressure at each control point to drop to a safe value is obtained, which is also the evacuation time at each control point.

[0083] Based on the group discharge test, the flow rate configuration of each discharge hole is shown in Table 2. The discharge time of each control point is obtained by solving the discharge time equation, as shown in Table 3.

[0084] Table 2. Flow rate configuration of the sludge discharge hole (m³) 3 / h)

[0085] sparse holes G1 G2 G3 G4 G5 flow 60 50 60 50 60

[0086] Table 3. Estimated evacuation time (days) for each control point.

[0087] Control Points A B C D E F G H Descent time 58.416 23.941 40.966 20.028 36.441 40.508 11.628 35.525

[0088] Obviously, the water discharge from the group of orifices is 280m³. 3 Under the condition of / h, the estimated descent time for each control point on the working face is between 11.628 and 58.416 days.

[0089] Step S4: Arrange drainage holes and establish a multi-hole drainage system in the well according to the water-rich abnormal zone; control the drainage of water in the well multi-hole drainage system based on the design drawdown and drainage time of the control points.

[0090] Establish a downhole multi-hole water release system, including: multi-hole water release device, water pressure and flow monitoring device, and surface control and data processing device.

[0091] The multi-hole drainage system includes: drainage holes, drainage pipes, and drainage valves. The drainage holes connect to the drainage pipes, which are equipped with drainage gates. The drainage pipes connect to the underground drainage tunnels. The drainage holes are distributed in different locations underground, and their number, diameter, and layout are optimized based on groundwater pressure, rock strata conditions, and drainage requirements. The pipes connecting the drainage holes to the underground drainage system guide groundwater from the drainage holes to the surface or designated drainage locations. Drainage valves are installed on the drainage holes or pipes to control the on / off state and flow rate of the water.

[0092] Water pressure and flow monitoring devices: The water pressure monitoring equipment uses capacitive sensors, the flow rate uses electromagnetic flow meters, and the water temperature monitoring equipment uses resistance temperature detectors (RTDs). These devices centrally collect data from pressure, flow rate, and water temperature, converting analog signals into digital signals for transmission and storage. The water pressure and flow monitoring devices are installed at drainage orifices and other critical locations to monitor pressure and flow changes in the drainage orifices in real time.

[0093] Ground control and data processing unit: This unit centrally manages the operation of the entire multi-hole drainage system, monitors the water pressure and flow rate of each drainage hole in real time, adjusts the opening and closing of drainage valves and the drainage volume, and predicts the water level drop and drainage pressure reduction time at each control point. Operators can use this system to monitor water pressure and flow rate data in real time, adjust the opening and closing of drainage valves and the drainage volume, view prediction results, and make corresponding operational decisions. Furthermore, it controls the drainage of the downhole multi-hole drainage system in conjunction with the designed drawdown and drainage time at the control points.

[0094] It should be noted that the order of the above embodiments of the present invention is merely for descriptive purposes and does not represent the superiority or inferiority of the embodiments. Furthermore, the above description focuses on specific embodiments of this specification. Additionally, the processes depicted in the accompanying drawings do not necessarily require a specific or sequential order to achieve the desired results. In some embodiments, multitasking and parallel processing are possible or may be advantageous.

[0095] The various embodiments in this specification are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

[0096] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for predicting water pressure drop and drainage time in downhole multi-hole drainage systems, characterized in that, The method includes: Step S1: Delineate the water-rich anomaly zone using multiple methods; obtain the hydraulic conductivity and elastic release coefficient of the target area based on the data from the multi-hole water release test; Step S2: Set up control points around the working face where the water-proof layer is thin, calculate the apparent water inrush coefficient and determine the design water level drawdown. Step S3: Predict the dredging time by combining the hydraulic conductivity, elastic release coefficient and design drawdown of each aquifer; Step S4: Based on the water-rich anomaly zone, rationally arrange drainage holes and establish a downhole multi-hole water release system; further apply the design drawdown and drainage time of the control points to dynamically regulate the operation of the water release system; The apparent water inrush coefficient of the control point is calculated as follows: the apparent water inrush coefficient of the control point is the ratio of the water head pressure borne by the water-resistant layer of the coal seam floor to the effective water-resistant layer thickness. The design drawdown for the control point is: ， in, This represents the design drawdown at the i-th control point; This represents the apparent water inrush coefficient at the i-th control point; Indicates the critical inrush coefficient; This represents the effective water-resistant layer thickness of the coal seam floor at the i-th control point; The method of predicting the drawdown time of the control point by combining the hydraulic conductivity, elastic release coefficient, and design drawdown of each aquifer includes: Calculate the total hydraulic conductivity of the target area based on the hydraulic conductivity of each aquifer; calculate the total elastic water release coefficient of the target area based on the elastic water release coefficient of each aquifer. Based on the total hydraulic conductivity and total elastic release coefficient of the target area, an equation for calculating the descent time is established. The equation for calculating the descent time of the control point is as follows: ， in, This represents the design drawdown at the i-th control point; n represents the number of drainage holes. r j This represents the distance between the j-th venting hole and the i-th control point; This represents the descent time of the i-th control point; Represents the integral variable; The total elastic water release coefficient of the target area is represented by the weighted sum of the elastic water release coefficients of each aquifer. The total hydraulic conductivity of the target area is the weighted sum of the hydraulic conductivity of each aquifer. The descent time of the control point is obtained by solving the equation for the descent time.

2. The method for predicting water pressure drop and drainage time in downhole multi-hole drainage according to claim 1, characterized in that, The delineation of the water-rich anomaly zone includes: Geological surveys, geophysical exploration, and remote sensing technologies were used to delineate water-rich anomaly zones.

3. The method for predicting water pressure drop and drainage time in downhole multi-hole drainage according to claim 1, characterized in that, The downhole multi-hole water drainage system includes: The downhole multi-hole water discharge system includes a multi-hole water discharge device, a water pressure and flow monitoring device, and a surface control and data processing device; wherein, the multi-hole water discharge device includes a drain hole, a water discharge pipe and a water discharge valve, and the water pressure and flow monitoring device includes a capacitive sensor and an electromagnetic flow meter.

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