In-situ leaching uranium mining layer permeability testing method

Abstract

The invention discloses an in-situ leaching uranium mining layer permeability testing method. The method comprises the following steps: acquiring a pressure signal of a water hammer at a wellhead of a target test well; carrying out normalization and noise reduction processing on the pressure signal; analyzing the processed pressure signal to obtain a first amplitude ratio, an attenuation rate and a pressure attenuation trend; the first amplitude ratio, the attenuation rate and the pressure attenuation trend are analyzed and calculated, and the ore bed permeability is obtained. Therefore, the permeability of the ore bed can be tested in the mine production process, the real-time performance is high, the operation is simple, the accuracy is high, and the method is suitable for popularization and application.

Description

Technical Field

[0001] This application relates to the field of ore layer parameter testing technology, and in particular to a method for testing the permeability of uranium ore layers obtained through in-situ leaching. Background Technology

[0002] In-situ leaching (ISL) is a crucial method for mining sandstone-type uranium deposits. It's a novel mining method that integrates mining and metallurgy, using a leaching agent that selectively reacts with the minerals to dissolve uranium without damaging the ore layer structure. This technology utilizes injection and extraction wells to form an injection-production unit. Filters are used in the overlapping area between the wellbore and the ore layer to achieve effective communication, enabling the injection of the leaching agent and the efficient extraction of uranium-containing solutions. Changes in the permeability of the ore-bearing layer during ISL are a core factor affecting the efficiency of ISL. Whether the permeability of the ore-bearing layer meets the requirements of the ISL process directly determines whether ISL can be successfully implemented and achieve the expected economic benefits. Changes in permeability not only restrict the flow characteristics of the leachate in the formation but also significantly affect the leaching efficiency of uranium.

[0003] The assessment of aquifer permeability primarily relies on laboratory experiments or field hydrological tests. Laboratory experiments typically involve collecting samples from the field and measuring the flow rate through the rock sample in a laboratory setting using Darcy's law to apply a stable upstream-downstream pressure difference, thereby calculating permeability; alternatively, permeability can be derived by maintaining a constant flow rate and measuring the upstream-downstream pressure difference. However, while laboratory core permeability tests can reflect formation permeability to some extent, limitations such as the representativeness of core samples, differences between testing conditions and the actual environment, and scale effects prevent the experimental results from fully and accurately representing the actual permeability of the aquifer. In-situ hydrological tests often employ pumping tests. After pumping reaches a steady state, steady-flow formulas such as the Theis formula are used to analyze the relationship between pumping intensity and drawdown. To ensure the reliability of the test results, the location and number of pumping wells and observation wells must be scientifically planned to ensure that the observed data accurately reflects the aquifer characteristics. Furthermore, precise measurements of key parameters such as pumping flow rate, drawdown, and time are necessary to improve data quality, making the operation quite complex.

[0004] Therefore, the permeability assessment of ore layers mainly adopts indoor leaching experiments or field injection tests, which have limitations such as poor real-time performance and complex operation, making it impossible to complete the ore layer permeability assessment in real time during the mining production process. Summary of the Invention

[0005] This application aims to address at least one of the technical problems existing in the prior art or related technologies.

[0006] In view of this, this application provides a method for testing the permeability of uranium ore layers obtained through in-situ leaching, comprising:

[0007] Collect water hammer pressure signals at the wellhead of the target test well;

[0008] The pressure signal is normalized and noise reduced.

[0009] The processed pressure signal was analyzed to obtain the first amplitude ratio, attenuation rate, and pressure attenuation trend;

[0010] The permeability of the ore layer was obtained by analyzing and calculating the first amplitude ratio, attenuation rate, and pressure attenuation trend.

[0011] For example, collecting water hammer pressure signals at the wellhead of the target test well includes:

[0012] Install the signal acquisition device at the wellhead of the target test well;

[0013] Pressure signals are collected using a signal acquisition device.

[0014] For example, collecting water hammer pressure signals at the wellhead of the target test well includes:

[0015] Before performing fluid injection on the target test well, the pressure signal at the wellhead of the target test well is collected.

[0016] Perform fluid injection operation on the target test well;

[0017] When the pressure signal reaches the first preset requirement, the injection operation is stopped to generate water hammer.

[0018] After a first preset time has elapsed since the injection operation was stopped, pressure signal acquisition will cease.

[0019] For example, the first preset requirement is that the average pressure change every 30 seconds is less than 3%;

[0020] The first preset duration is greater than or equal to 15 minutes.

[0021] For example, the sampling frequency of the signal acquisition device is greater than or equal to 100Hz.

[0022] For example, normalizing and denoising the pressure signal includes:

[0023] Normalize the pressure signal;

[0024] A combination of low-pass filtering and median filtering is used to reduce noise in the normalized water hammer signal.

[0025] For example, analyzing the processed pressure signal to obtain the first amplitude includes:

[0026] The processed pressure signal is analyzed to obtain the first pressure difference and the second pressure difference;

[0027] The first amplitude is obtained by dividing the first pressure difference by the second pressure difference.

[0028] Among them, the first pressure difference is the pressure difference between the first trough and the first peak, the first trough is the first trough after the injection operation is stopped in the processed pressure signal, and the first peak is the first peak after the first trough.

[0029] The second pressure difference is the pressure difference between the stable pressure and the first trough. The stable pressure is the pressure value in the processed pressure signal that meets the first preset requirement.

[0030] For example, the attenuation rate is obtained by analyzing the processed water hammer signal, including:

[0031] Using the formula y = Ae -Bt The peak and valley values ​​of the portion of the pressure signal after the injection operation is stopped are fitted, and B in the formula represents the attenuation rate.

[0032] Where y represents each set of peak and valley values ​​in the processed pressure signal, the peak and valley values ​​represent the pressure difference between the valley and the next adjacent peak in the processed pressure signal, t is the normalized time, and A and B are the fitted parameters.

[0033] For example, the processed water hammer signal is analyzed to obtain the pressure attenuation trend, including:

[0034] Analyze the portion of the processed pressure signal after the injection operation has stopped;

[0035] Extract the time and pressure values ​​corresponding to the first target point. The first target point is the point on the pressure signal where the average pressure of each peak and the next adjacent trough during the water hammer oscillation process is represented.

[0036] Extract the time and pressure values ​​corresponding to the second target point, which is the point on the pressure signal after the water hammer oscillation stops.

[0037] Use formula A pressure attenuation trend line is formed by fitting the first target point and the second target point, and D represents the pressure attenuation trend.

[0038] Where z is the pressure value corresponding to the first target point and the second target point, t is the time corresponding to the first target point and the second target point, and C and D are the fitted parameters.

[0039] For example, the permeability of the ore layer is obtained by analyzing and calculating the first amplitude ratio, attenuation rate, and pressure attenuation trend, including:

[0040] The permeability coefficient of the ore layer location in the target test well is obtained by inversion using the first amplitude ratio, attenuation rate, and pressure attenuation trend.

[0041] The permeability testing method for uranium ore layers provided in this application involves collecting water hammer pressure signals at the wellhead of the target test well. After normalizing and denoising the collected pressure signals, the method analyzes them to obtain a first amplitude ratio, attenuation rate, and pressure attenuation trend. By analyzing and calculating these parameters, the permeability of the ore layer can be tested. Compared to indoor leaching experiments, this method simplifies sampling and allows for real-time acquisition of water hammer pressure signals, offering strong real-time performance. Compared to on-site injection tests in related technologies, this method converts the measurement of water hammer pressure signals inside the target test well to measurement at the wellhead, simplifying the measurement of drawdown. The method is convenient to operate, allowing for permeability testing of the ore layer through normalization, denoising, and analytical calculations of the collected pressure signals. This enables permeability testing during mine production, offering strong real-time performance, simple operation, high accuracy, and wide applicability, making it suitable for widespread application.

[0042] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0043] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. Wherein:

[0044] Figure 1 One of the flowcharts of the permeability testing method for in-situ leaching uranium ore layers provided in the embodiments of this application is shown;

[0045] Figure 2 One of the field implementation diagrams of the in-situ leaching uranium ore layer permeability testing method provided in the embodiments of this application is shown;

[0046] Figure 3 One of the schematic diagrams of processed pressure signal feature analysis provided in the embodiments of this application is shown, used to determine the first amplitude;

[0047] Figure 4 This is a second schematic diagram of the processed pressure signal feature analysis provided in an embodiment of this application, used to determine the attenuation rate;

[0048] Figure 5 The third schematic diagram of the processed pressure signal feature analysis provided in the embodiment of this application is shown, which is used to determine the pressure attenuation trend;

[0049] Figure 6 One of the comparison charts of the raw and filtered data of normalized pressure provided in the embodiments of this application is shown;

[0050] Figure 7 It shows Figure 6 The diagram shows the normalized pressure signal feature analysis of the filtered data.

[0051] in, Figure 2 The correspondence between the reference numerals and component names in the attached drawings is as follows:

[0052] 100 Target test well, 110 Wellhead, 120 Wellbore, 130 Filter, 200 Signal acquisition device, 300 Injection pump, 400 Central control room, 500 Control valve, 600 Flow meter, 700 Surface, 800 Non-ore layer, 900 Ore-bearing layer. Detailed Implementation

[0053] To better understand the above-mentioned objectives, features, and advantages of this application, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0054] Many specific details are set forth in the following description in order to provide a full understanding of this application. However, this application may also be implemented in other ways different from those described herein. Therefore, the scope of protection of this application is not limited to the specific embodiments disclosed below.

[0055] like Figure 1 As shown in the embodiments of this application, a method for testing the permeability of uranium ore layers obtained through in-situ leaching is provided, comprising:

[0056] Step 1100: Collect the water hammer pressure signal at the wellhead 110 of the target test well 100.

[0057] Here, target test well 100 can be understood as a well that is directly connected to the ore layer to be tested for permeability. For example... Figure 2As shown, the target test well 100 includes a wellbore 120 located underground. The formation includes a non-mineralized layer 800 and a mineralized layer 900. The wellbore 120 extends through the non-mineralized layer 800 to the mineralized layer 900. The purpose of the in-situ leaching permeability testing method for uranium ore layers provided in this application is to test the permeability of the mineralized layer 900. The overlapping area between the wellbore 120 and the mineralized layer 900 is effectively connected using a filter 130 for the injection of the leaching agent and the efficient extraction of the uranium-containing solution. The wellhead 110 can be understood as the opening connecting the wellbore 120 of the target test well 100 to the surface 700. Water hammer can be understood as: in a pressurized pipeline (such as the wellbore 120), due to some external cause (such as a valve suddenly closing or a pump unit suddenly stopping), the water flow velocity suddenly changes, causing water hammer. This hydraulic phenomenon is called water hammer.

[0058] In this embodiment, by collecting the water hammer pressure signal at the wellhead 110 of the target test well 100, real-time measurement of the pressure signal at the wellhead 110 of the target test well 100 can be achieved, and direct measurement of the water hammer pressure signal generated within the wellbore 120 of the target test well 100 can be realized. Compared with permeability testing in indoor leaching experiments, this method offers stronger real-time performance. Furthermore, by measuring the water hammer pressure signal generated within the wellbore 120 of the target test well 100 at the wellhead 110, compared to the related technology where on-site injection tests for permeability testing require measuring the water hammer pressure signal within the wellbore of the target test well, the signal acquisition device 200 for pressure signal acquisition is more convenient to set up, easier to assemble and disassemble, and simpler to operate.

[0059] Step 1200: Normalize and reduce noise in the pressure signal.

[0060] By normalizing the pressure signal to eliminate the differences in the dimensions of the collected pressure signal, the data is standardized, which helps to improve the accuracy of calculation and analysis, and thus improve the test precision.

[0061] By denoising the normalized pressure signal, the quality of the pressure signal can be improved, the accuracy of information extraction can be enhanced, and the subsequent processing effect can be optimized. This will help to further improve the accuracy of the analysis and thus improve the test precision.

[0062] Step 1300: Analyze the processed pressure signal to obtain the first amplitude ratio, attenuation rate, and pressure attenuation trend;

[0063] Step 1400: Analyze and calculate the first amplitude ratio, attenuation rate, and pressure attenuation trend to obtain the ore layer permeability.

[0064] By analyzing the processed pressure signal, the first amplitude ratio, attenuation rate, and pressure attenuation trend are obtained, providing basic data for subsequent analysis and calculation of the ore layer permeability. The ore layer permeability is obtained by analyzing and calculating the first amplitude ratio, attenuation rate, and pressure attenuation trend, thereby realizing the testing of ore layer permeability.

[0065] In other words, the permeability testing method for uranium ore layers provided in this application involves collecting water hammer pressure signals at the wellhead 110 of the target test well 100, normalizing and denoising the collected pressure signals, and then analyzing them to obtain the first amplitude ratio, attenuation rate, and pressure attenuation trend. By analyzing and calculating the first amplitude ratio, attenuation rate, and pressure attenuation trend, the permeability of the ore layer can be tested. Compared with indoor leaching experiments for permeability testing, this method simplifies the sampling operation and can collect water hammer pressure signals in real time, exhibiting strong real-time performance. Compared with the field injection test for permeability testing in related technologies, this method converts the measurement of water hammer pressure signals inside the target test well 100 into the measurement of water hammer pressure signals at the wellhead 110, and simplifies the measurement of drawdown. It is easy to operate and can achieve the test of mineral layer permeability by normalizing, denoising, and performing analysis and calculation based on the collected pressure signals. This allows for the testing of mineral layer permeability during the mining process, with strong real-time performance, simple operation, high accuracy, and strong applicability, making it suitable for widespread application.

[0066] The acquisition of water hammer pressure signals at the wellhead 110 of the target test well 100 can be understood as acquiring pressure signals at the wellhead 110 of the target test well 100 for at least one period of time before, during, and after the occurrence of water hammer.

[0067] In some possible embodiments provided in this application, the water hammer pressure signal is collected at the wellhead 110 of the target test well 100, including:

[0068] The signal acquisition device 200 is installed at the wellhead 110 of the target test well 100;

[0069] The pressure signal is acquired using the signal acquisition device 200.

[0070] In this embodiment, the signal acquisition device 200 can acquire pressure signals. By installing the signal acquisition device 200 at the wellhead 110 of the target test well 100, the pressure signal at the wellhead 110 of the target test well 100 can be acquired, thereby acquiring the water hammer pressure signal at the wellhead 110 of the target test well 100. Since the wellhead 110 is located close to the ground surface 700, the signal acquisition device 200 can be placed on or near the ground surface 700. This is more convenient than the related technologies that require the signal acquisition device to be placed inside the wellbore below the ground surface 700 for signal acquisition, thus facilitating the arrangement of the signal acquisition device 200.

[0071] The signal acquisition device 200 can be a pressure sensor, such as a high-precision, high-sampling-rate pressure sensor installed at the wellhead 110 of the target test well 100. Furthermore, after the pressure sensor is installed, a pressure test can be performed to verify the sealing between the pressure sensor and the wellbore 120 of the target test well 100, ensuring no leakage at the installation location of the pressure sensor, thereby guaranteeing the accuracy and reliability of the pressure signal acquisition.

[0072] In some possible embodiments provided in this application, the water hammer pressure signal is collected at the wellhead 110 of the target test well 100, including:

[0073] Before performing fluid injection on the target test well 100, the pressure signal at the wellhead 110 of the target test well 100 is collected.

[0074] Fluid injection operation was performed on the target test well 100;

[0075] When the pressure signal reaches the first preset requirement, the injection operation is stopped to generate water hammer.

[0076] After a first preset time has elapsed since the injection operation was stopped, pressure signal acquisition will cease.

[0077] The purpose of injecting fluid into the target test well 100 and then stopping the injection is to generate water hammer inside the wellbore 120 of the target test well 100.

[0078] In this embodiment, pressure signals at the wellhead 110 of the target test well 100 are collected before the injection operation is performed on the target test well 100. Pressure signals at the wellhead 110 of the target test well 100 are continuously collected during the injection operation and the process of stopping the injection operation to generate water hammer. Pressure signals are also continuously collected for a first preset time after the injection operation stops and the water hammer is generated. This ensures that the collected pressure signals include the pressure signals before the water hammer is generated, at the time the water hammer is generated, and for the first preset time after the water hammer is generated. This ensures the integrity of the water hammer pressure signal collection and helps to improve the test accuracy.

[0079] Before performing the injection operation on the target test well 100, the signal acquisition device 200 installed at the wellhead 110 of the target test well 100 can be activated to collect the pressure at the wellhead 110.

[0080] Among them, such as Figure 2 As shown, the injection pump 300 can be used to inject liquid into the target test well 100, allowing the liquid to flow from the wellhead 110 into the wellbore 120 and then into the ore-bearing layer 900. Specifically, an injection pump 300 adapted to the wellhead 110 can be installed to achieve precise flow control. Alternatively, the injection pump 300 can be communicatively connected to the control room 400, allowing the control room 400 to remotely adjust the flow rate of the injection pump 300, thereby ensuring that the target test well 100 can smoothly perform downhole injection operations. Alternatively, a control valve 500 can be installed on the pipeline between the injection pump 300 and the inlet, allowing the control room 400 to remotely adjust the control valve 500 to regulate the flow rate of the injection pump 300. A flow meter 600 can be installed on the pipeline connecting the injection pump 300 and the wellhead 110 to measure the output flow rate of the injection pump 300. Understandably, the injection flow rate of injection pump 300 needs to be dynamically adjusted according to the actual site conditions to ensure that the pressure inside wellbore 120 can be significantly increased and maintained within a reasonable range.

[0081] When the collected pressure signal reaches the first preset requirement, it indicates that the pressure at the wellhead 110 of the target test well 100 is stabilizing. At this time, quickly stopping the injection operation can cause a sudden change in the flow velocity in the wellbore 120, and at the same time, the pressure will fluctuate significantly. This ensures that water hammer can be generated smoothly, so as to ensure that the collected pressure signal has clear fluctuations, which is beneficial to improving the test accuracy.

[0082] Specifically, the first preset requirement is that the average pressure change every 30 seconds is less than 3%, such as 0%, 1%, 2%, 2.5%, 2.9%, or other values. In other words, when the pressure at the wellhead 110 of the target test well reaches the first preset requirement, it indicates that the pressure at wellhead 110 is stable, and the injection operation can be stopped. Specifically, the injection pump 300 can be directly shut off to stop injection, or a pipeline connecting the injection pump 300 and wellhead 110 can be installed on the ground surface 700, with a control valve 500 installed on the pipeline. By quickly closing the control valve 500, the flow rate at wellhead 110 of the target test well 100 can be rapidly reduced to zero.

[0083] After the injection operation is stopped, signal acquisition does not immediately cease. Instead, the pressure signal at wellhead 110 is continuously monitored and acquired. Pressure signal acquisition stops after a first preset time period following the cessation of injection. In other words, after the injection operation stops, the pressure at wellhead 110 needs to be continuously monitored for at least the first preset time period. Specifically, the first preset time period can be greater than or equal to 15 minutes, such as 15 minutes, 20 minutes, 30 minutes, 40 minutes, or other durations. During the continuous monitoring of wellhead 110 pressure after the injection operation stops, it is strictly forbidden to close wellhead 110 or perform any operation that may interfere with the wellhead 110 pressure to ensure the integrity and interference-free nature of the water hammer signal. Understandably, pressure signal acquisition stops after the first preset time period, i.e., after the monitoring time ends, such as by shutting down the signal acquisition device 200 installed at wellhead 110.

[0084] In some possible embodiments provided in this application, the sampling frequency of the signal acquisition device 200 is greater than or equal to 100Hz. By reasonably setting the sampling frequency of the signal acquisition device 200, the measurement accuracy and resolution of the signal acquisition device 200 can be improved, and the data processing capability of the signal acquisition device 200 can be ensured to be within a reasonable range, thereby improving the sensitivity of the test performed by the signal acquisition device 200. It is understood that the sampling frequency of the signal acquisition device 200 can be 100Hz, 110Hz, 125Hz, 150Hz, or other frequencies.

[0085] In some possible embodiments provided in this application, the pressure signal is normalized and noise-reduced, including:

[0086] Normalize the pressure signal;

[0087] A combination of low-pass filtering and median filtering is used to reduce noise in the normalized water hammer signal.

[0088] In this embodiment, the water hammer pressure signal collected at the wellhead 110 of the target test well 100 is normalized to eliminate the differences in the different dimensions of the collected pressure signal, thus standardizing the data and improving the accuracy of calculation and analysis, thereby enhancing the test precision. Then, a combination of low-pass filtering and median filtering is used to denoise the normalized water hammer signal, improving the quality of the pressure signal, enhancing the accuracy of information extraction, and optimizing subsequent processing effects.

[0089] Specifically, the cutoff frequency of the low-pass filter is typically set to no less than 10Hz, and the specific value can be adjusted appropriately according to the length and material characteristics of the casing in the wellbore 120. The filtering result needs to retain the fluctuation characteristics of the water hammer oscillation in order to remove high-frequency noise from the water hammer signal collected at the wellhead 110.

[0090] like Figure 3 As shown, in some possible embodiments provided in this application, the processed pressure signal is analyzed to obtain a first amplitude, including:

[0091] The processed pressure signal is analyzed to obtain the first pressure difference and the second pressure difference;

[0092] The first amplitude is obtained by dividing the first pressure difference by the second pressure difference.

[0093] Wherein, the first pressure difference is the processed pressure difference between the first trough and the first peak, the first trough is the first trough after the injection operation is stopped in the processed pressure signal, and the first peak is the first peak after the first trough.

[0094] The second pressure difference is the pressure difference between the stable pressure and the first trough. The stable pressure is the pressure value in the processed pressure signal that meets the first preset requirement.

[0095] This embodiment discloses a specific scheme for analyzing the processed pressure signal to obtain the first amplitude. As mentioned above, the pressure signal collected at the wellhead 110 of the target test well 100 includes the pressure signal before the injection operation, the pressure signal when the injection operation stops, and the pressure signal after the injection operation stops for a first preset time. The first trough in the normalized and noise-reduced pressure signal after the injection operation stops is taken as the first trough, and the first peak adjacent to and following the first trough is taken as the first peak. The pressure difference between the normalized and noise-reduced pressure signals corresponding to the first trough and the first peak is calculated and recorded as the first pressure difference. The pressure value in the normalized and noise-reduced pressure signal that meets the first preset requirement is taken as the stable pressure, that is, the pressure value in the normalized and noise-reduced pressure signal corresponding to the pressure at wellhead 110 before the injection operation stops and the pressure reaches stability when the first preset requirement is met is taken as the stable pressure. The pressure difference between the stable pressure and the first trough is calculated and recorded as the second pressure difference. The first amplitude is obtained by dividing the first pressure difference by the second pressure difference. Since the first amplitude is obtained by analyzing and calculating the characteristics of the processed pressure signal, the calculation is simple and helps to improve the accuracy of the determined first amplitude, thereby improving the test precision.

[0096] like Figure 4 As shown, in some possible embodiments provided in this application, the processed water hammer signal is analyzed to obtain the attenuation rate, including:

[0097] Using the formula y = Ae -Bt The peak and valley values ​​of the portion of the pressure signal after the injection operation is stopped are fitted, and B in the formula represents the attenuation rate.

[0098] Where y represents each set of peak and valley values ​​in the processed pressure signal, the peak and valley values ​​represent the pressure difference between the valley and the next adjacent peak in the processed pressure signal, t is the normalized time, and A and B are the fitted parameters.

[0099] This embodiment discloses a specific scheme for analyzing the processed pressure signal to obtain the attenuation rate. The attenuation rate reflects the oscillation attenuation characteristics of the water hammer signal. By analyzing the portion of the processed pressure signal after the injection operation is stopped, and considering that water hammer occurs within 100 meters of the target test well after the injection operation is stopped, the attenuation rate is calculated using the exponential formula y = Ae^(-1 / 2). -BtThe peak and trough values ​​of the processed pressure signal after the injection operation is stopped are fitted, i.e., the portion of the processed pressure signal after water hammer is generated is fitted. Here, y represents each set of peak and trough values ​​of the water hammer signal, t is the normalized time, and A and B are the fitted parameters, where B reflects the attenuation rate of the pressure signal after water hammer, thus confirming the attenuation rate of the pressure signal after water hammer. Since the attenuation rate is obtained by analyzing and calculating this characteristic of the processed pressure signal, the calculation is simple, which helps improve the accuracy of the determined attenuation rate and thus improves the test precision.

[0100] It is understandable that when using the exponential form of the formula y = Ae -Bt In the process of fitting the peak and valley values ​​of the portion of the pressure signal after the injection operation is stopped, other formulas can also be used for fitting, and this application does not make specific limitations on this.

[0101] like Figure 5 As shown, in some possible embodiments provided in this application, the processed water hammer signal is analyzed to obtain the pressure attenuation trend, including:

[0102] Analyze the portion of the processed pressure signal after the injection operation has stopped;

[0103] Extract the time and pressure values ​​corresponding to the first target point. The first target point is the point on the pressure signal where the average pressure of each peak and the next adjacent trough during the water hammer oscillation process is represented.

[0104] Extract the time and pressure values ​​corresponding to the second target point, which is the point on the pressure signal after the water hammer oscillation stops.

[0105] Use formula A pressure attenuation trend line is formed by fitting the first target point and the second target point, and D represents the pressure attenuation trend of the water hammer signal.

[0106] Where z is the pressure value corresponding to the first target point and the second target point, t is the time corresponding to the first target point and the second target point, and C and D are the fitted parameters.

[0107] This embodiment discloses a specific scheme for analyzing the processed pressure signal to obtain the pressure decay trend. The analysis focuses on the portion of the processed pressure signal after the injection operation has stopped, specifically the portion after water hammer occurs. It is understood that when the injection operation stops, a water hammer occurs, and this water hammer exhibits oscillation. During the oscillation, the pressure difference between the peak and the next adjacent trough of the processed pressure signal is relatively large, which can be understood as greater than or equal to a preset pressure difference. When the water hammer oscillation stops, the pressure difference between the peak and the next adjacent trough of the pressure signal is relatively small, which can be understood as less than the preset pressure difference. In other words, after the water hammer oscillation stops, the pressure signal tends to stabilize, with minimal or almost no fluctuation.

[0108] The point on the pressure signal where the average pressure of each peak and the next adjacent trough during the water hammer oscillation is recorded as the first target point, where the pressure difference between the peak and the next adjacent trough at this point is greater than or equal to a preset pressure difference. The point on the pressure signal after the water hammer oscillation stops is recorded as the second target point, where the pressure difference between the peaks and the next adjacent troughs of the pressure signal after the second target point is less than or equal to a preset pressure difference.

[0109] By extracting the time and pressure values ​​corresponding to the first target point, and then extracting the time and pressure values ​​corresponding to the second target point, the following steps are taken: A pressure attenuation trend line is formed by fitting the first and second target points, where z is the pressure value corresponding to the first and second target points, t is the time corresponding to the first and second target points, and C and D are the fitted parameters, with D representing the pressure attenuation trend. Since the pressure attenuation trend is obtained by analyzing and calculating this characteristic of the processed pressure signal, the calculation is simple, which helps improve the accuracy of the determined pressure attenuation trend and thus improves the test precision.

[0110] Understandably, in utilizing In the process of fitting the first target point and the second target point to form the pressure attenuation trend line, other formulas can also be used for fitting, and this application does not make specific limitations on this.

[0111] In some possible embodiments provided in this application, the first amplitude ratio, attenuation rate, and pressure attenuation trend are analyzed and calculated to obtain the ore layer permeability, including:

[0112] The permeability coefficient of the ore layer at the target test well 100 is obtained by inversion using the first amplitude ratio, attenuation rate, and pressure attenuation trend.

[0113] Specifically, diagnostic methods can be used to perform in-depth analysis and calculation of the first amplitude ratio, attenuation rate, and pressure attenuation trend, thereby inverting the permeability coefficient at the ore-bearing layer 900 position of the target test well 100, so as to realize the test of the ore layer permeability coefficient.

[0114] The permeability testing method for uranium ore layers provided in this application is characterized by its simple operation and strong real-time capability. It can usually complete the determination of the 900 permeability coefficient of the ore-bearing layer within 1 hour, providing reliable technical support for the safe and green permeability assessment of uranium ore layers and is suitable for widespread application.

[0115] Understandably, the sampling frequency of the pressure signal collected by the signal acquisition device 200 during the water hammer ignition process, the pressure balance judgment standard at the wellhead 110, the water hammer signal monitoring duration after the injection operation is stopped, and the filtering method for noise reduction can be changed according to the actual situation on site to meet the needs of the mineral layer permeability testing process.

[0116] like Figure 2 As shown in the specific embodiment, the permeability testing method for uranium ore layers provided in this application was used to conduct permeability testing on an ore-bearing layer 900 of a uranium mine through a target test well 100. A control valve 500 is installed on the pipeline between the wellhead 110 of the target test well 100 and the injection pump 300. The control valve 500 is communicatively connected to the central control room 400. The central control room 400 controls the control valve 500 to control the flow rate change of the injection pump 300, thereby controlling the flow rate change in the wellbore 120 of the target injection well. Specifically, a flow meter 600 is installed on the pipeline between the wellhead 110 and the injection pump 300 to measure the output flow rate of the injection pump 300. The signal acquisition device 200 is a pressure sensor. Before the test begins, a high-frequency pressure sensor is placed at the wellhead 110 to ensure that the high-frequency pressure sensor is located after the control valve 500 to ensure that the pressure fluctuations in the wellbore 120 can be collected when the flow rate changes. After ensuring the wellbore 120 is properly sealed, the injection pump 300 is controlled via the central control room 400 to perform the injection operation, allowing the target test well 100 to inject fluid at a rate of 120m. 3 Fluid is injected downhole at a flow rate of / day.

[0117] When the pressure signal acquired by the pressure sensor reaches an average pressure difference change of less than 3% every 30 seconds, such as when the pressure sensor or other display device connected to the pressure sensor shows an average pressure difference change of less than 3% every 30 seconds, the control valve 500 on the pipeline between the wellhead 110 and the injection pump 300 is quickly closed via the control room 400, causing the flow rate in the wellbore 120 of the target test well 100 to rapidly drop to zero. The pressure at the wellhead 110 is continuously monitored using the pressure sensor for 30 minutes. After the monitoring period ends, pressure data acquisition is stopped, and the pressure sensor is turned off. The pressure at the wellhead 110 of the target test well 100 is normalized, low-pass filtered, and median filtered. The cutoff frequency of the low-pass filter is 7Hz. Specifically, Figure 6 The chart shows a comparison between the raw and filtered data of the normalized pressure. Figure 6 The blue data in the image represents the original data before filtering. Figure 6 The red data in the image represents the filtered data.

[0118] like Figure 7 As shown, for Figure 6 By performing feature analysis on the normalized pressure signal of the filtered data shown, the first amplitude ratio, attenuation rate, and pressure attenuation trend within 20 minutes can be obtained. Using software to analyze and calculate the first amplitude ratio, attenuation rate, and pressure attenuation trend within 20 minutes of the processed pressure signal, the permeability coefficient of the ore-bearing layer 900 is obtained, resulting in 0.2 m / Day.

[0119] Those skilled in the art will understand that the accompanying drawings are merely schematic diagrams of a preferred embodiment, and the modules or processes shown in the drawings are not necessarily essential for implementing this application. Those skilled in the art will understand that the modules in the apparatus of the embodiment can be distributed within the apparatus of the embodiment as described, or can be located in one or more apparatuses different from this embodiment, with corresponding changes. The modules of the above-described embodiment can be combined into one module, or further divided into multiple sub-modules. The serial numbers of this application mentioned above are merely descriptive and do not represent the superiority or inferiority of the embodiment. The above disclosures are only a few specific embodiments of this application; however, this application is not limited thereto, and any variations conceived by those skilled in the art should fall within the protection scope of this application.

Claims

1. A method for testing the permeability of uranium ore layers obtained through in-situ leaching, characterized in that, include: Collect water hammer pressure signals at the wellhead of the target test well; The pressure signal is normalized and noise reduced. The processed pressure signal is analyzed to obtain the first amplitude ratio, attenuation rate, and pressure attenuation trend. The permeability of the ore layer is obtained by analyzing and calculating the first amplitude ratio, the attenuation rate, and the pressure attenuation trend.

2. The method for testing the permeability of uranium ore layers by in-situ leaching according to claim 1, characterized in that, The process of collecting water hammer pressure signals at the wellhead of the target test well includes: The signal acquisition device is installed at the wellhead of the target test well; The pressure signal is acquired using the signal acquisition device.

3. The method for testing the permeability of uranium ore layers by in-situ leaching according to claim 1 or 2, characterized in that, The process of collecting water hammer pressure signals at the wellhead of the target test well includes: Before performing fluid injection on the target test well, the pressure signal at the wellhead of the target test well is collected. The injection operation is performed on the target test well; When the pressure signal reaches the first preset requirement, the injection operation is stopped to generate water hammer. After a first preset time has elapsed since the injection operation was stopped, the acquisition of the pressure signal is stopped.

4. The method for testing the permeability of uranium ore layers by in-situ leaching according to claim 3, characterized in that, The first preset requirement is that the average pressure change every 30 seconds is less than 3%. The first preset duration is greater than or equal to 15 minutes.

5. The method for testing the permeability of uranium ore layers by in-situ leaching according to claim 2, characterized in that, The sampling frequency of the signal acquisition device is greater than or equal to 100Hz.

6. The method for testing the permeability of uranium ore layers by in-situ leaching according to claim 1, characterized in that, The normalization and noise reduction processing of the pressure signal includes: The pressure signal is normalized. The water hammer signal that has been normalized is denoised by a combination of low-pass filtering and median filtering.

7. The method for testing the permeability of uranium ore layers by in-situ leaching according to claim 3, characterized in that, The step of analyzing the processed pressure signal to obtain the first amplitude includes: The processed pressure signal is analyzed to obtain the first pressure difference and the second pressure difference. The first pressure difference is divided by the second pressure difference to obtain the first amplitude. Wherein, the first pressure difference is the pressure difference between the first trough and the first peak, the first trough is the first trough in the processed pressure signal after the injection operation is stopped, and the first peak is the first peak after the first trough. The second pressure difference is the pressure difference between the stable pressure and the first trough, where the stable pressure is the pressure value in the processed pressure signal that meets the first preset requirement.

8. The method for testing the permeability of uranium ore layers by in-situ leaching according to claim 3, characterized in that, The process of analyzing the processed water hammer signal to obtain the attenuation rate includes: Using the formula y = Ae -Bt The peak and valley values ​​of the portion of the pressure signal after the injection operation is stopped are fitted, and B in the formula represents the attenuation rate; Where y represents each set of peak and valley values ​​of the processed pressure signal, the peak and valley values ​​represent the pressure difference between the valley and the next adjacent peak in the processed pressure signal, t is the normalized time, and A and B are the fitted parameters.

9. The method for testing the permeability of uranium ore layers by in-situ leaching according to claim 3, characterized in that, The analysis of the processed water hammer signal to obtain the pressure attenuation trend includes: The portion of the processed pressure signal after the injection operation has been stopped is analyzed. Extract the time and pressure values ​​corresponding to the first target point, where the first target point is the point on the pressure signal where the average pressure of each peak and the next adjacent trough during the water hammer oscillation process is expressed. Extract the time and pressure values ​​corresponding to the second target point, which is the point on the pressure signal after the water hammer oscillation stops; Use formula A pressure attenuation trend line is formed by fitting the first target point and the second target point, and D represents the pressure attenuation trend. Where z is the pressure value corresponding to the first target point and the second target point, t is the time corresponding to the first target point and the second target point, and C and D are the fitted parameters.

10. The method for testing the permeability of uranium ore layers obtained through in-situ leaching according to any one of claims 1 to 9, characterized in that, The step of analyzing and calculating the first amplitude ratio, the attenuation rate, and the pressure attenuation trend to obtain the ore layer permeability includes: The permeability coefficient of the ore layer location of the target test well is obtained by inversion using the first amplitude ratio, the attenuation rate, and the pressure attenuation trend.

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