Method for measuring and calculating water level in drill hole based on energy conservation

Abstract

The invention relates to the field of uranium ore, in particular to a method for measuring and calculating the water level in a drill hole based on energy conservation, which is suitable for real-time acquisition of large-scale and long-term water level data in the drill hole. The method mainly comprises the following steps: 1, establishing a drilling water level calculation formula according to the law of conservation of energy; 2, setting a water level measuring and calculating time period; 3, power parameters are collected, and liquid mass and flow velocity are calculated; 4, determining the liquid lifting height of the submersible pump; 5, determining the head loss of the liquid flowing along the pipeline; 6, determining a pressure water head at the tail end of the liquid conveying system; 7, the real-time comprehensive efficiency of the submersible pump is determined; and 8, measuring and calculating related water level data in the drill hole. According to the invention, real-time acquisition of the water level data in the drill hole is realized, the water level measurement error is reduced, the pump stopping operation time of the liquid pumping hole is reduced, the operation risk is reduced, and the project investment cost is saved.

Description

Technical Field

[0001] The present invention relates to the field of uranium mines, and in particular to a method for measuring water levels in boreholes based on energy conservation, which is suitable for real-time acquisition of large-scale, long-term borehole water level data. Background Art

[0002] Groundwater is crucial to the development of uranium and other mineral resources, particularly sandstone uranium deposits exploited through in-situ leaching. Insufficient groundwater replenishment during in-situ leaching can, at best, cause failures in the submersible pumps used to lift the uranium solution, impacting its delivery. In worse cases, it can interrupt the leaching process within the underground ore layer, directly impacting uranium development and even rendering the deposit inoperable.

[0003] Regarding the acquisition of water level data in boreholes, there are mainly the following methods in the existing technology. The first is to first install a water level meter without a transmission cable in the target borehole, and after the set water level monitoring period is over, remove the water level meter and read the data; the second is to install a water level meter with its own data transmission cable in the target borehole, and establish a water level monitoring system on the surface to achieve data acquisition; the third is to adopt other monitoring methods, such as: installing various sensors (pressure sensors, ultrasonic sensors, etc.) below the water level in the borehole, installing corresponding instrument panels, recorders, transmitters, receivers and other instruments and equipment on the surface, and obtaining water level data through sensor measurement.

[0004] Due to the generally small borehole diameter, the existing technology mainly has problems such as untimely data acquisition, interference in data collection, time-consuming and inconvenient installation and maintenance of monitoring equipment, and high cost of long-term monitoring of group holes. It cannot meet the real-time, long-term and economical acquisition needs of large-scale (hundreds / thousands) target borehole water level data, nor can it provide stable water level data support for the efficient development of sandstone-type uranium resources. Summary of the Invention

[0005] 1. Purpose

[0006] The purpose of the present invention is to provide a method for measuring the water level in a borehole based on the law of energy conservation. This method breaks through the limitations of conventional water level acquisition methods such as sensor measurement, replaces water level monitoring with water level measurement, and thus realizes real-time, long-term and economical acquisition of water level data in the borehole, providing stable and reliable data support for the development of mineral resources.

[0007] 2. Technical solution

[0008] To achieve the above object, the present invention provides the following solutions:

[0009] (1) Establish a calculation formula related to the water level in the borehole

[0010] The submersible pump used to lift liquid in the borehole and the pipelines used to transport the liquid within the borehole and on the surface constitute a "liquid transportation system." According to the law of conservation of energy, when a submersible pump transports a certain flow of liquid along the pipeline, the energy provided by the submersible pump is used to raise the liquid's head, overcome flow losses along the pipeline, and overcome residual pressure at the end of the management, thus maintaining a certain flow rate.

[0011] Within a certain period of time, the product of the submersible pump's operating power and comprehensive efficiency is equal to the sum of four energies, which is related to the mass of the lifted liquid, gravitational acceleration, liquid flow rate, etc., see Formula 1.

[0012]

[0013] In the formula: P represents the real-time power of the submersible pump; η represents the comprehensive efficiency of the submersible pump, which is between 0 and 1; t represents the set time period; m represents the mass of liquid lifted during the set time period; g represents the acceleration of gravity; h represents the acceleration of gravity. z Indicates the height of the liquid lifted by the submersible pump, which is related to the depth of the water level in the borehole; h f Indicates the head loss when the liquid flows along the pipeline; h y It represents the pressure head at the end of the liquid delivery system; v represents the liquid flow rate.

[0014] (2) Set the time period for water level measurement

[0015] A time period within 1 to 5 minutes is preferred, such as 1 minute, 2 minutes, 3 minutes, 4 minutes, and 5 minutes. The time period is related to the number of water level measurement points, and one time period constitutes one water level measurement point.

[0016] (3) Collect power parameters and calculate liquid mass and flow rate

[0017] The real-time power P of the submersible pump is collected through a frequency converter. Preferably, data reading and transmission are achieved through information technology.

[0018] The liquid mass m is determined by calculation using Formula 2.

[0019]

[0020] Where: Q is the liquid flow rate of the submersible pump in the target borehole, unit is m 3 / h; t is the set time period, in min; ρ is the fluid density, in kg / m 3 .

[0021] The liquid flow rate v is determined by calculation using formula 3.

[0022]

[0023] In the formula, π represents the ratio of circumference to diameter, which is a constant; r represents the radius of the pipeline through which the fluid flows, and its unit is m.

[0024] (4) Determine the calculation formula for the liquid height lifted by the submersible pump

[0025] Submersible pump lifts liquid height h z , which is related to the performance of the pump, the depth of the water level in the borehole, etc.

[0026] For a target borehole where the height of the end of the liquid delivery pipeline is equivalent to the ground elevation of the orifice, the height of the liquid lifted by the submersible pump is related to the depth of the water level in the target borehole (the height from the water level to the ground) and the depth of the submersible pump. The expression formula is:

[0027] h z =H d -h m Formula 4

[0028] In the formula: H d Indicates the depth of the submersible pump in the target borehole, in m; h m Indicates the depth of water level in the borehole, in meters.

[0029] For a target borehole where the height of the end of the liquid delivery pipeline is different from the ground elevation of the orifice, the height of the liquid lifted by the submersible pump is related to the water level depth in the target borehole, the ground elevation, and the elevation of the end of the liquid delivery pipeline. The expression formula is:

[0030] h z =h m +(H j -H w ) Formula 5

[0031] In the formula: H j Indicates the elevation of the end of the target borehole liquid delivery pipeline, in meters; H w Indicates the ground elevation of the target drilling hole, in meters.

[0032] (5) Determine the head loss when the liquid flows along the pipeline

[0033] The head loss h when the liquid flows along the pipeline f , which is related to pipeline length, pipe wall roughness, Reynolds number, etc. An indirect measurement method is preferably used to determine the head loss of liquid flowing along the pipeline at different flow rates by measuring the pressure difference between the two ends of the measured pipeline at different flow rates. The flow rate-pipeline head loss formula is determined by polynomial fitting. The head loss along the pipeline is preferably determined in units of 100m (hundred meters) of pipeline length to reduce measurement errors caused by too small data. The flow measurement range, target pipeline specifications, length, etc. are determined according to the test requirements.

[0034] (6) Determine the pressure head at the end of the liquid delivery system

[0035] The pressure head h at the end of the liquid delivery system y , which is related to fluid properties. Direct measurement is preferred. Install a pressure monitoring instrument at the end of the system to be measured, adjust the frequency of the frequency converter to control the flow rate of the submersible pump, and simultaneously monitor the pressure changes at the end of the system at different flow rates. This test method determines the pressure head at the end of the liquid delivery system. A polynomial fitting formula is then used to determine the flow rate-system end pressure head loss. The optional single frequency adjustment range is 1-2 Hz, and the frequency modulation interval is 10-30 minutes.

[0036] (7) Determine the real-time comprehensive efficiency of the submersible pump

[0037] The real-time comprehensive efficiency η of a submersible pump is related to factors such as pump structure, aging wear, motor power, motor performance, and liquid viscosity. An indirect measurement method is preferred. A water level meter with its own transmission cable is installed in the target borehole. The submersible pump flow rate is controlled by adjusting the frequency converter frequency. Water level data changes in the target borehole are simultaneously monitored at different flow rates. Based on experimentally measured data such as the pump's liquid lift height, power, and flow rate, the comprehensive efficiency of the submersible pump at different flow rates is determined. A polynomial fitting formula is then used to determine the flow rate-submersible pump comprehensive efficiency. The optional single frequency adjustment range is 1 to 2 Hz, with a modulation interval of 10 to 30 minutes.

[0038] (8) Calculate relevant water level data in the borehole

[0039] Based on the real-time power of the submersible pump collected in step (3), the head loss formula when the liquid flows along the pipeline determined in step (5), the pressure head formula at the end of the liquid delivery system determined in step (6), and the comprehensive efficiency formula of the submersible pump determined in step (7), the liquid mass and liquid flow rate parameters calculated within the set time period are used to calculate the liquid lifting height of the submersible pump according to formula 1; the water level depth in the target borehole is calculated according to formula 4 or formula 5, and the water level elevation h in the target borehole is calculated according to formula 6. b , calculate the water column height h above the submersible pump according to formula 7 s .

[0040] h b =H w -h m Formula 6

[0041] h s =H d -h m Formula 7

[0042] In order to facilitate the comprehensive use of water level data and realize the value of data, it is preferred to use information technology to establish a special system for measuring water level data in boreholes based on the law of conservation of energy; within the allowable accuracy range, the water level calculation parameters can be simplified by discarding sub-items with small proportions and negligible items based on the proportions of the four sub-items on the right side of Formula 1.

[0043] 3. Effect

[0044] According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects: First, it breaks through the limitations of conventional water level acquisition methods such as sensor measurement, replaces water level monitoring with water level measurement, and can calculate the water level change data of the target borehole under any flow rate in real time, with a measurement error within 5m; second, it changes the previous working mode of borehole water level measurement that requires the installation and extraction of water level meters, reduces the labor intensity of operators, reduces the pump stop time of the pumping hole, and eliminates the risks of equipment damage, equipment falling off, etc. caused by the installation of water level meters; third, except for the cost of establishing a special water level measurement system, there is no need to invest funds in other aspects, and the large-scale and engineering application value is high. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 This is a flow chart of the water level measurement method based on energy conservation of the present invention;

[0046] Figure 2 This is a fitting diagram of flow rate versus head loss along a 100-meter pipeline in an embodiment of the present invention;

[0047] Figure 3 This is a fitting diagram of flow rate-elbow local head loss in an embodiment of the present invention;

[0048] Figure 4 This is a fitting diagram of flow rate versus pressure head at the end of the system in an embodiment of the present invention;

[0049] Figure 5 This is a flow rate-submersible pump comprehensive efficiency fitting diagram in an embodiment of the present invention;

[0050] Figure 6 Schematic diagram of the structure of a measurement system based on energy conservation in an embodiment of the present invention;

[0051] Figure 7 It is a flow-water level measurement / monitoring data curve diagram of a target borehole in an embodiment of the present invention. DETAILED DESCRIPTION

[0052] Figure 1This is a flow chart of a method for measuring water level in a borehole based on energy conservation according to an embodiment of the present application. The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention to verify the effectiveness of the method of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. 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.

[0053] The target borehole inner diameters of a sandstone-type in-situ leaching uranium deposit in Inner Mongolia are mainly 128mm and 164mm. The submersible pumps used to lift the liquid are mainly 4-inch pumps and 6-inch pumps. The liquid flow rate of the submersible pump is controlled by a frequency converter and measured by an electromagnetic flowmeter. The liquid delivery pipeline connected to the submersible pump has an inner diameter of 45mm and a pipeline length between 250 and 550m. The connecting parts between the pipelines are mainly 90° standard elbows. The pressure at the end of the pipeline delivery system is within 0.2MPa. The implementation and verification were carried out using three target boreholes equipped with submersible pumps of different performances, among which: borehole 1 was installed with an old 4-inch submersible pump, borehole 2 was installed with a new 6-inch submersible pump, and borehole 3 was installed with a new 4-inch submersible pump. The specific implementation method is as follows:

[0054] Step 1: Establish a calculation formula related to the water level in the borehole

[0055] The three target boreholes are used to form three liquid delivery systems. Within a certain period of time, when the submersible pump delivers liquid along the pipeline, the corresponding liquid delivery system follows the law of conservation of energy. Based on the principle of conservation of energy, the calculation formula related to the water level in the borehole is shown in Formula 1. The relevant term is the liquid height h raised by the submersible pump. z .

[0056]

[0057] Step 2: Set the time period for water level measurement

[0058] Take 1 minute as a time period to ensure that the measured water level changes can be observed in a relatively short period of time; take the average value of 10 points in the time period and remove the maximum and minimum values ​​to avoid abnormal flow data points affecting the measurement results.

[0059] Step 3: Collect power parameters and calculate liquid mass and flow rate

[0060] The real-time power of the three submersible pumps during operation is collected through the frequency converter, and technical means are used to transmit the real-time power to the water level measurement system to be constructed.

[0061] The liquid mass is calculated using Formula 2, and the liquid flow rate is calculated using Formula 3.

[0062]

[0063] Step 4: Determine the calculation formula for the submersible pump to lift the liquid height

[0064] The height of the end of the liquid delivery pipeline of the three target boreholes is different from the ground elevation of the borehole mouth. The liquid lifting height of the submersible pump is calculated using Formula 5.

[0065] h z =h m +(H j -H w ) Formula 5

[0066] Step 5: Determine the head loss as the liquid flows along the pipeline

[0067] a. Install digital pressure gauge 1 at the liquid inlet end of the PE composite pipe to be tested with an inner diameter of 45mm and a length of 240m, and digital pressure gauge 2 at the liquid outlet end. The front end of digital pressure gauge 1 is connected to the submersible pump through a pipeline, and the rear end of digital pressure gauge 2 is connected to the electromagnetic flowmeter. The liquid flow is controlled by a frequency converter.

[0068] b. Start the submersible pump at low frequency and gradually increase the frequency converter. Simultaneously observe and record the electromagnetic flowmeter reading and the pressure difference at both ends of the pipeline under different flow conditions. The flow range is 3m 3 / h~11.5m 3 / h.

[0069] c. Based on the test data, the flow rate-head loss formula 8 is obtained by fitting, as shown in Figure 2 shown.

[0070] y=0.0712x 2 +0.1298x Formula 8

[0071] d. Install digital pressure gauge 1 at the liquid inlet end of a PE composite pipe with an inner diameter of 45mm and a length of 240m. Connect the liquid outlet to a 20m pipeline of the same model through an elbow. Connect digital pressure gauge 2 and an electromagnetic flowmeter to the end of the 20m pipeline. The liquid flow is controlled by a frequency converter.

[0072] e. Start the submersible pump at low frequency and gradually increase the frequency converter frequency. Simultaneously observe and record the electromagnetic flowmeter reading and the pipeline pressure difference under different flow conditions. The flow range is 3.5m 3 / h~11.2m 3 / h.

[0073] f. According to the test data, the flow-elbow local head loss formula 9 is obtained by fitting, as shown in Figure 3 shown.

[0074] y = -0.0004x 3+ 0.0097x 2 + 0.017x - 0.1834 Formula 9

[0075] Step 6: Determine the pressure head at the end of the liquid delivery system

[0076] a. Install an electromagnetic flowmeter and a digital pressure gauge at the end of the test borehole pipeline with a larger flow adjustment space.

[0077] b. Start the submersible pump at low frequency and gradually increase the frequency converter frequency. Simultaneously observe and record the electromagnetic flowmeter reading and the system end pressure under different flow conditions. The flow range is 3.2m 3 / h~9.4m 3 / h.

[0078] c. According to the test data, the flow rate-pressure head formula at the end of the system is obtained by fitting 10, as shown in Figure 4 shown.

[0079] y = 0.9721x + 7.3858 Formula 10

[0080] Step 7: Determine the real-time overall efficiency of the submersible pump

[0081] a. Install dynamic water level monitors with built-in cables in the 1#, 2#, and 3# target boreholes to ensure that water level data can be read in real time.

[0082] b. After the submersible pump is running stably, carry out frequency modulation test by frequency reduction / increase, and synchronously record parameters such as flow rate under stable operation at each frequency, liquid level height from the submersible pump to the dynamic water level, and real-time power displayed on the inverter.

[0083] c. Based on the test data, the flow-submersible pump comprehensive efficiency formula is obtained by fitting. For borehole 1#, see formula 11; for borehole 2#, see formula 12; for borehole 3#, see formula 13. Figure 5 shown.

[0084] y = -0.0159x 2 + 0.1345x + 0.0846 Formula 11

[0085] y = -0.0037x 2 + 0.087x + 0.0767 Formula 12

[0086] y = 0.0013x 3 - 0.0273x 2 + 0.1578x + 0.1967 Formula 13

[0087] Step 8: Calculate relevant water level data in the borehole

[0088] Substitute the time period set in step 2, the power parameters, calculated liquid mass, and flow data collected in step 3, and the formulas determined in steps 5 to 7 into formula 1 in step 1 to obtain the liquid lifting height of the submersible pump; substitute the liquid lifting height of the submersible pump into formula 5 in step 4 to obtain the water level depth in the target borehole at different flow rates; substitute the water level depth in the borehole into formulas 6 and 7 to obtain the water level elevation in the target borehole and the water column height above the submersible pump at different flow rates.

[0089] like Figure 6 As shown in the figure, a borehole water level measurement system is constructed through information technology, enabling automatic retrieval of relevant parameters such as power and flow rate, and automatic calculation of water level data. The system comprises a fixed parameter setting module based on wellhead elevation and pipeline length, an efficiency coefficient setting module based on the multi-power coefficient of the submersible pump's comprehensive efficiency, an efficiency coefficient display module based on the calculated submersible pump's operational efficiency, and a water level data display module based on the calculated dynamic water level depth, dynamic water level elevation, and the height of the water column above the submersible pump.

[0090] like Figure 7 As shown in the figure, when comparing the water level data of the target borehole under different flow rates, the water level data obtained by real-time measurement by the system and the water level data obtained by monitoring by the water level meter, the water level measurement error is controlled within 5m. Figure 7 This is the flow-water level measurement / monitoring data curve for target borehole 3#.

Claims

1. A method for measuring water level in a borehole based on energy conservation, characterized by: Step 1: Based on the law of conservation of energy, establish a formula for calculating the borehole water level; Step 2: Set the water level measurement time period; Step 3: Collect power parameters and calculate the liquid mass and flow rate; Step 4: Determine the height to which the submersible pump lifts the liquid; Step 5: Determine the head loss of the liquid flowing along the pipeline; Step 6: Determine the pressure head at the end of the liquid delivery system; Step 7: Determine the real-time comprehensive efficiency of the submersible pump; Step 8: Calculate relevant water level data in the borehole.

2. The method for measuring water level in a borehole based on energy conservation according to claim 1, characterized in that: Step 1: According to the law of conservation of energy, establish the calculation formula for the borehole water level, see formula 1: In formula 1, P represents the real-time power of the submersible pump; η represents the comprehensive efficiency of the submersible pump, which is between 0 and 1; t represents the set time period; m represents the mass of liquid lifted during the set time period; g represents the acceleration of gravity; h represents the acceleration of gravity. z Indicates the height of the liquid lifted by the submersible pump, which is related to the depth of the water level in the borehole; h f Indicates the head loss when the liquid flows along the pipeline; h y It represents the pressure head at the end of the liquid delivery system; v represents the liquid flow rate.

3. The method for measuring water level in a borehole based on energy conservation according to claim 1, characterized in that: Step 2: Set the water level measurement time period, specifically including: preferably a time period within 1 to 5 minutes, including 1 minute, 2 minutes, 3 minutes, 4 minutes, and 5 minutes. One time period constitutes one water level measurement point.

4. The method for measuring water level in a borehole based on energy conservation according to claim 1, characterized in that: Step 3: Collect power parameters and calculate liquid mass and flow rate. Specifically, collect data from the submersible pump using the frequency converter and calculate the liquid mass m using Formula 2: In formula 2, Q is the liquid flow rate of the submersible pump in the target borehole, in m 3 / h; t is the set time period, in min; ρ is the fluid density, in kg / m 3 ; The liquid flow rate v is calculated using formula 3: In formula 3, r represents the radius of the pipeline through which the fluid flows, and the unit is m.

5. The method for measuring water level in a borehole based on energy conservation according to claim 1, characterized in that: Step 4: Determine the liquid lifting height h of the submersible pump z Specifically, for the target borehole where the end height of the liquid delivery pipeline is equivalent to the ground elevation of the orifice, the height of the liquid lifted by the submersible pump is equal to the buried depth of the water level in the target borehole, and the lowering depth of the submersible pump h z The specific calculation formula is: h z =H d -h m Formula 4 In formula 4, H d Indicates the depth of the submersible pump in the target borehole, in m; h m Indicates the depth of water level in the borehole, in m; For target boreholes where the end elevation of the liquid delivery pipeline is different from the ground elevation of the orifice, the submersible pump lifts the liquid to a height of h z It is related to the water level depth in the target borehole, the ground elevation, and the elevation of the end of the liquid delivery pipeline. The specific calculation formula is: h z = h m + (H j - H w ) Equation 5 In formula 5, H j Indicates the elevation of the end of the target borehole liquid delivery pipeline, in meters; H w Indicates the ground elevation of the target drilling hole, in meters.

6. The method for measuring water level in a borehole based on energy conservation according to claim 1, characterized in that: Step 5: Determine the head loss h when the liquid flows along the pipeline f Specifically, it includes: using an indirect measurement method to determine the pressure difference between the two ends of the pipeline to be tested under different flow rates, and preferably the head loss along the way is measured in units of 100m pipeline length.

7. The method for measuring water level in a borehole based on energy conservation according to claim 1, characterized in that: Step 6: Determine the pressure head h at the end of the liquid delivery system y Specifically, it includes: using a direct measurement method, installing a pressure monitoring instrument on the terminal pipeline of the system to be measured, controlling the flow change of the submersible pump by adjusting the frequency of the frequency converter, and synchronously monitoring the test method for the change of the system terminal pressure under different flow rates; the single frequency adjustment amplitude is 1 to 2 Hz, and the frequency modulation time interval is 10 to 30 minutes.

8. The method for measuring water level in a borehole based on energy conservation according to claim 1, characterized in that: Step 7: Determine the real-time comprehensive efficiency η of the submersible pump, specifically including: using an indirect measurement method, installing a water level meter with its own transmission cable in the target borehole, controlling the flow change of the submersible pump by adjusting the frequency of the inverter, and simultaneously monitoring the changes in the water level data in the target borehole under different flow rates. Based on the experimentally measured data such as the liquid lifting height, power, and flow rate of the submersible pump, determine the comprehensive efficiency η of the submersible pump under different flow rates; the single frequency adjustment amplitude is 1 to 2 Hz, and the frequency modulation time interval is 10 to 30 minutes.

9. The method for measuring water level in a borehole based on energy conservation according to claim 1, characterized in that: Step 8: Calculate the water level data in the borehole. Based on the real-time power of the submersible pump collected in step 3, the head loss formula when the liquid flows along the pipeline determined in step 5, the pressure head formula at the end of the liquid delivery system determined in step 6, and the comprehensive efficiency formula of the submersible pump determined in step 7, the liquid mass and liquid flow rate parameters calculated within the set time period are used to calculate the liquid lifting height of the submersible pump according to formula 1; the water level depth in the target borehole is calculated according to formula 4 or formula 5, and the water level elevation h in the target borehole is calculated according to formula 6. b , calculate the water column height h above the submersible pump according to formula 7 s : h b =H w -h m Formula 6 h s =H d -h m Formula 7 In formula 6, h b Indicates the water level elevation in the target borehole, H w Indicates the target drilling ground elevation, h m Indicates the depth of water level in the borehole; In formula 7, h s Indicates the height of the water column above the submersible pump, H d Indicates the lowering depth of the submersible pump in the target borehole, h m Indicates the depth of water level in the borehole.

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