A kind of pumping and injecting integrated in-situ leaching uranium production well and thick sandstone uranium ore body mining method

Abstract

The application relates to a pumping and injecting integrated in-situ leaching uranium production well and a method for mining thick sandstone uranium ore bodies. The pumping and injecting integrated in-situ leaching uranium production well comprises a well body, a liquid injection section, a solid wall section and a liquid pumping section, the liquid injection section, the solid wall section and the liquid pumping section are completely located in the ore body, a liquid pumping pipe and a liquid injection pipe, the liquid pumping pipe and the liquid injection pipe are arranged in the well body, the lower end of the liquid pumping pipe is independently connected with the liquid pumping section, the lower end of the liquid injection pipe is independently connected with the liquid injection section, and a water stop packer is arranged in the solid wall section. The production well is a pumping and injecting integrated novel in-situ leaching uranium production well, breaks through the single function mode of only realizing liquid injection or only realizing liquid pumping of a traditional in-situ leaching uranium mine production well, realizes the double functions of liquid pumping and liquid injection of a single production well through the method of constructing a hydraulic connection channel at different vertical positions of the same production well, and further realizes the target of efficient leaching of thick sandstone uranium ore bodies.

Description

Technical Field

[0001] This application relates to the field of mining engineering technology, specifically to an integrated extraction and injection uranium production well and a method for mining thick sandstone uranium ore bodies. Background Technology

[0002] Sandstone-type uranium resources account for more than 50% of my country's proven uranium reserves. In-situ leaching is the mainstream technology for the development and utilization of sandstone-type uranium deposits. The natural uranium production capacity of in-situ leaching uranium mines accounts for more than 90% of the total domestic natural uranium production capacity, making them the main force in ensuring my country's natural uranium production. The in-situ leaching process involves constructing a series of pumping wells and injection wells (collectively referred to as production wells) on the surface and using the pumping and injection operations of the production wells to inject leaching solution, leach uranium, and lift the leaching solution.

[0003] Currently, sandstone-type uranium deposits mined using in-situ leaching are shallow, with uranium ore bodies generally less than 10m thick. Therefore, existing in-situ leaching uranium mines have production wells with single filters, and pumping wells are used only for pumping, while injection wells are used only for injection.

[0004] Based on years of production practice, the spacing between production wells in my country's in-situ leaching uranium mines is generally 30-40m. This ensures a certain leaching range while reasonably reducing the number of production wells to be constructed, thus saving costs associated with in-situ leaching mining of sandstone uranium.

[0005] With years of development and utilization of shallow sandstone uranium resources in my country, recoverable resources are becoming increasingly scarce. The development of deep sandstone uranium deposits has become an inevitable trend in my country's future uranium resource exploration and development. Currently, the proven sandstone-type uranium deposits such as Mengba and Sanwan are characterized by their enormous thickness. Related data shows that the main ore body thickness of these deep sandstone uranium deposits is generally greater than 10 meters, with some thick sections reaching 40 meters. The traditional in-situ leaching production method, where pumping and injection wells operate independently and a single filter is used, is difficult to meet the high-efficiency leaching requirements of thick sandstone uranium ore bodies. On the one hand, when the pumping and injection wells only perform pumping and injection work, and the filter length is much shorter than the ore body thickness, the leaching range constructed by the production well can only cover a portion of the sandstone uranium ore body, resulting in a waste of sandstone uranium resources. On the other hand, increasing the filter length to cover the entire uranium ore body thickness will dilute the leaching solution, reducing leaching efficiency. Summary of the Invention

[0006] The purpose of this application is to provide a method for mining thick sandstone uranium ore bodies using an integrated extraction and injection in-situ leaching production well. This method achieves efficient in-situ leaching mining of thick sandstone uranium ore bodies without increasing the construction cost of the production well. More specifically, this application provides a layout and construction technology for an integrated extraction and injection in-situ leaching production well, which can adapt to the in-situ leaching mining requirements of thick sandstone uranium ore bodies, achieving efficient mining of thick sandstone uranium ore bodies and improving the utilization rate of sandstone uranium resources.

[0007] To achieve the above objectives, this application adopts the following technical solution: A type of integrated extraction and injection uranium production well includes: The wellbore includes an injection section, a solid wall section, and a pumping section, all of which are entirely within the ore body. The well includes a pumping pipe and an injection pipe, both installed within the wellbore. The lower end of the pumping pipe is independently connected to the pumping section, and the lower end of the injection pipe is independently connected to the injection section. A water-stopping seal is installed within the solid wall section.

[0008] Preferably, the injection section and the extraction section are respectively provided with leaching channels, which are provided by water jetting, water jetting, or installing filters, and the length of the leaching channels is 3-15m.

[0009] Preferably, the length of the solid wall section is 1-10m, and the rated sealing pressure of the built-in water-stop packer is ≥1.2×maximum working injection pressure + original hydrostatic pressure.

[0010] A method for in-situ leaching mining of thick sandstone uranium ore bodies, using any of the above-mentioned production wells, includes the following steps: (1) Three-dimensional geological modeling: Combining the sequential Gaussian simulation method, the geological-ore body characteristic parameters and hydrogeological parameters are spatially mapped to establish a three-dimensional ore body model; (2) Construction of flow field numerical model: The hydrogeological parameters of the three-dimensional ore body model are spatially mapped to the numerical model grid, and the partition assignment is completed according to lithology and ore body distribution to construct a three-dimensional finite difference seepage numerical model. (3) The leaching channel design adopts the production well with integrated injection and extraction, and simulates and determines the start and end positions of the injection section and the extraction section of a single well, the optimal injection flow rate and extraction flow rate, and determines the effective leaching range of a single well, providing a basic basis for setting the well spacing of the production wells; (4) Construction of integrated extraction and injection uranium production wells and leaching mining.

[0011] Preferably, in step (1), the planar grid size is ≤10m×10m and the vertical single-layer thickness is ≤1m.

[0012] Preferably, the vertical single-layer thickness of the ore body section is 0.5m.

[0013] Preferably, in step (2), the planar grid within 20m of the production well is densified, and the grid size is ≤2m×2m.

[0014] Preferably, in step (3), the simulation determines that the injection pressure does not exceed 80% of the formation fracture pressure, the pumping dynamic water level is not lower than the maximum elevation of the top plate of the ore-bearing aquifer, and ensures that the injection-production balance rate is ≥80% and the ore body sweep rate within the well network control range is ≥70%.

[0015] Preferably, in step (4), the construction process includes well drilling, well logging, casing installation, drilling and cementing, well logging verification, opening of the leaching channel, equipment installation, and well washing and inspection of the effect of the leaching channel.

[0016] Preferably, the well washing meets the qualified standards; the requirements for the effect inspection of the leaching channel are as follows: the permeability coefficient in the near-well zone is more than 1.5 times higher than the original permeability coefficient of the mineralized aquifer; the drawdown and flow rate are stable in three consecutive pumping tests, with a relative error of ≤10%; the water level fitting error is ≤30%, and the flow rate fitting error is ≤30%, ensuring that the model can accurately predict the formation seepage behavior; there is no cross-flow short circuit.

[0017] This application has the following advantages: 1. The production well of this application is a new type of in-situ leaching uranium production well that integrates pumping and injection. It breaks through the single-function mode of traditional in-situ leaching uranium mine production wells that only realize injection or only pumping. By constructing hydraulic connection channels at different vertical positions in the same production well, a single production well can simultaneously have the dual functions of pumping and injection, thereby achieving the goal of efficient leaching of thick sandstone uranium ore bodies.

[0018] 2. The mining method of this application integrates multi-dimensional data such as geology, hydrology, geophysics, and drilling, and uses numerical simulation methods to determine the opening position of the filter section of the integrated production well for in-situ leaching uranium extraction and injection.

[0019] 3. The mining method of this application integrates multi-dimensional data such as geology, hydrology, geophysics, and drilling, and uses numerical simulation methods to determine the effective leaching range of the integrated production well for in-situ leaching uranium extraction and injection. Based on this, the optimal well spacing is determined to save drilling construction costs.

[0020] 4. The mining method proposed in this application innovates collaboratively in four core aspects: modeling, simulation, design, and construction, which effectively improves the leaching efficiency and resource utilization of thick sandstone uranium ore bodies and reduces construction costs. Attached Figure Description

[0021] Figure 1This is a schematic diagram of a uranium production well with integrated extraction and injection. 1 is the extraction pipe; 2 is the injection pipe; 3 is the stop seal packer.

[0022] Figure 2 A schematic cross-section of a thick sandstone uranium ore body for in-situ leaching mining. Detailed Implementation

[0023] The present application will now be described in detail with reference to the accompanying drawings and embodiments. Any modifications or substitutions made to the methods, steps, or conditions of the present application without departing from the spirit and substance of the present application shall fall within the scope of the present application.

[0024] It should be noted that the terms "upper" and "lower" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0025] A type of integrated extraction and injection uranium production well includes: The wellbore comprises an injection section, a solid-wall section, and a pumping section, all of which are entirely within the ore body. The injection section can be located above the pumping section, or vice versa. Leaching channels are constructed in both the injection and pumping sections, using methods such as hydraulic perforation, hydraulic slotting, or filter installation. The preferred length of these channels is 3-15m, including options like 3m, 5m, 8m, 10m, and 15m, providing a hydraulic connection between the integrated injection and pumping production well and the ore body. The solid-wall section refers to a smooth, intact section of the production casing without any openings, perforations, filter slots, or filters. The preferred length of the solid-wall section is 1-10m, and the specific length can be determined based on factors such as the vertical thickness of the ore body.

[0026] The pumping pipe and the injection pipe are installed in the wellbore. The lower end of the pumping pipe is independently connected to the pumping section, and the upper end extends to the ground. The lower end of the injection pipe is independently connected to the injection section, and the upper end extends to the ground.

[0027] The packer, installed within the solid wall section between the injection and extraction sections, has a rated packing pressure ≥ 1.2 × maximum working injection pressure + original hydrostatic pressure. It addresses downhole injection pressure fluctuations and ensures reliable sealing. This sealing structure achieves complete isolation between the injection and extraction sections, eliminating the risk of short-circuiting of the leaching fluid, while also providing sufficient safety margin to adapt to downhole pressure fluctuations, thus solving the core sealing technology problem of simultaneous injection and extraction within the same well.

[0028] The well casing structure adopts a combination of surface casing and production casing to form a two-stage well structure. The material of the production casing is selected according to the burial depth of the ore body, such as UPVC, fiberglass or seamless steel pipe, to ensure that the strength requirements under production conditions are met.

[0029] This application adopts an integrated extraction and injection well design, which lays the extraction pipe and injection pipe in the same production well. Combined with sandblasting perforations, hydraulic slits, or the installation of filters, it solves the technical problem that traditional single-well single-filter design cannot achieve vertical economic and efficient leaching of thick ore bodies. It significantly reduces the number of wells, lowers construction costs, and ensures efficient coverage of the leaching solution seepage path, thereby improving the uniformity of ore body leaching.

[0030] In view of the characteristics of thick sandstone uranium ore bodies, such as long vertical extension, strong heterogeneity of strata, and great difficulty in leaching, this application proposes an in-situ leaching mining method for thick sandstone uranium ore bodies, which specifically includes the following steps: (1) Three-dimensional geological modeling: Combining the sequential Gaussian simulation method, the geological-ore body characteristic parameters and hydrogeological parameters are spatially mapped to establish a three-dimensional ore body model and achieve precise parameter correlation. Among them, the geological-ore body characteristic parameters and hydrogeological parameters include porosity, permeability coefficient, uranium grade, uranium thickness, etc.

[0031] The preferred planar grid size is ≤10m×10m, and the vertical single-layer thickness is ≤1m. The vertical single-layer thickness of the orebody section can be densified to 0.5m to finely characterize the heterogeneity of the strata. The grid of the orebody section is densified in a targeted manner to accurately adapt to the characteristics of thick orebody.

[0032] (2) Numerical model construction of flow field: The hydrogeological parameters of the three-dimensional ore body model, such as permeability, porosity, water storage rate, and hydraulic conductivity, are spatially mapped to the numerical model grid. The parameters are assigned according to lithology and ore body distribution, and a three-dimensional finite difference seepage numerical model is constructed. This realizes the parameter linkage between the geological model and the seepage model, which can improve the simulation's relevance. For example, the planar grid within 20m of the production well (referring to a distance ≤20m) is refined, with a grid size ≤2m×2m.

[0033] This step involves model identification and verification: using measured data from pumping and pressure tests, model parameters are inverted and identified to complete model verification.

[0034] (3) Design of leaching channels: Numerical simulation is used, with flow field calculations performed via MODFLOW and a corresponding MODPATH particle tracking module for leaching range simulation. Combining seepage simulation with particle tracking helps predict the leaching range and avoid blind zone risks. The design adopts an integrated injection and extraction production well, with two leaching channels arranged at different vertical depths within the well body. The injection section, solid wall section, and extraction section are completely contained within the ore body, and penetration of the top and bottom aquitards is strictly prohibited. This application breaks through the traditional separate injection and production model, arranging injection, solid wall, and extraction sections at different vertical depths within the same well, adapting to the vertical extension characteristics of thick ore bodies and reducing drilling costs.

[0035] Based on three-dimensional geological modeling and flow field numerical model, the optimal leaching channel scheme for integrated injection and extraction production wells is determined through numerical simulation optimization. Using single-well injection pressure, pumping dynamic water level and other conditions as evaluation criteria, the start and end positions of the injection and pumping sections are determined, as well as the optimal injection and pumping flow rates under the corresponding leaching channel conditions. Ultimately, the maximum effective leaching range of a single well is achieved, providing a basis for setting the well spacing of production wells.

[0036] Specifically, simulations determine that the injection pressure of a single well does not exceed 80% of the formation fracturing pressure, and the dynamic water level during pumping is not lower than the maximum elevation of the top plate of the ore-bearing aquifer, ensuring an injection-production balance rate of ≥80%. In this application, the injection-production balance rate refers to the ratio of the total flow rate of the leaching solution injected into the injection pipe to the total flow rate of the liquid extracted from the pumping pipe during the same time period. Finally, the affected area of ​​a single well is determined, providing a basic basis for designing the well spacing of integrated injection-pumping leaching production wells, balancing efficiency and safety.

[0037] Based on the optimization of single-well parameters, a numerical model at the well group scale is constructed to optimize the well network configuration and well spacing. Considering the planar distribution characteristics of the ore body, the well network layout should simultaneously take into account the number of integrated pumping and injection production wells to reduce well construction costs and the leaching coverage of the sandstone uranium ore body to minimize uranium resource waste. The ore body sweep rate within the well network control area should be ≥70%, avoiding mutual interference between adjacent well flow fields to prevent short circuits or leaching dead zones.

[0038] (4) Construction of an integrated in-situ leaching uranium production well and leaching mining. The construction process includes wellbore drilling, well logging, casing installation, drilling and cementing, well logging verification, leaching channel opening, equipment installation, and well washing and leaching channel effect verification. Well washing complies with EJ / T 20039-2014 "Requirements for Drilling and Well Completion Technology of In-situ Leaching Uranium Production" and GB 50521-2023 "Technical Standards for Uranium Mining and Metallurgy Engineering in Nuclear Industry". The leaching channel effect verification requires that the permeability coefficient in the near-wellbore zone be increased by more than 1.5 times compared with the original permeability coefficient of the ore-bearing aquifer; the drawdown and flow rate are stable in three consecutive pumping tests with a relative error of ≤10%; the water level fitting error is ≤30% and the flow rate fitting error is ≤30%, ensuring that the model can accurately predict formation seepage behavior; and there is no cross-flow short circuit.

[0039] Example 1 This embodiment provides an integrated extraction and injection uranium production well, such as... Figure 1 As shown, it includes: The extraction pipe 1 and injection pipe 2 are installed in the well body. The lower end of the extraction pipe 1 is independently connected to the extraction section, and the upper end extends to the ground. The lower end of the injection pipe 2 is independently connected to the injection section, and the upper end extends to the ground. The submersible pump extracts uranium-containing leachate from the lower part of the ore body and transports it to the hydrometallurgical plant for processing through the extraction pipe 1.

[0040] The injection section, solid wall section, and extraction section are all located within the ore body. The injection section and extraction section are each equipped with a leaching channel, with a length of 10m.

[0041] The waterstop packer 3 is a Y341 type washable high-pressure packer with a rated working pressure ≥15MPa and a temperature resistance ≥60℃. It is installed in the solid wall section between the injection section and the pumping section, and the length of the solid wall section is 5m. The rated sealing pressure of the waterstop packer 3 = 1.2 × maximum working injection pressure + original hydrostatic pressure.

[0042] Well casing structure, including surface casing and production casing.

[0043] Example 2 This embodiment provides an in-situ leaching mining method for thick sandstone uranium ore bodies, specifically including the following steps: The first step is three-dimensional geological modeling.

[0044] The system collects and organizes hydrological, geological, geophysical, and drilling data of the target uranium deposit. Based on relevant information from drilling core logging, geophysical logging, and hydrogeological tests, it determines key information such as the stratigraphic structure, lithological zoning, thickness, and permeability of the ore-bearing aquifer. Using mainstream international modeling software such as GMS or Peterl, combined with the sequential Gaussian simulation method, it spatially maps parameters such as porosity, permeability coefficient, uranium grade, and uranium thickness to establish a three-dimensional ore body model. The mesh accuracy meets the following requirements: planar mesh size ≤ 10m × 10m, vertical single-layer thickness ≤ 1m (mineralized to 0.2m in ore body sections), thus refining the characterization of stratigraphic heterogeneity.

[0045] The second step is to construct a numerical model of the flow field.

[0046] A three-dimensional finite difference seepage numerical model was constructed using the MODFLOW-2005 module of GMS software. The modeling process is as follows: 1. Mesh Discretization: The mesh is matched with the 3D geological model mesh to complete spatial discretization. The planar mesh size is 2m×2m to 5m×5m, and the vertical mesh is discretized according to the strata. The mesh of the ore body segment is refined, and the total number of meshes meets the simulation accuracy requirements.

[0047] 2. Parameter partitioning assignment: The hydrogeological parameters (permeability coefficient, porosity, water storage rate, and hydraulic conductivity) of the three-dimensional ore body model are spatially mapped to the numerical model grid, and parameter partitioning assignment is completed according to lithology and ore body distribution.

[0048] 3. Boundary and initial conditions: Boundary conditions are set according to the characteristics of groundwater recharge and discharge in the region; the initial hydraulic head field is assigned using the measured static water level from boreholes to reconstruct the natural initial flow field of the ore deposit.

[0049] 4. Model Identification and Validation: Model parameters are inverted and identified using measured data from pumping and pressure tests to complete model validation.

[0050] The third step is the design of the leaching channel.

[0051] The design of an integrated injection-extraction uranium production well involves designing two leaching channels at different vertical depths within the same production well. The injection section, solid-wall section, and extraction section must be completely situated within the ore-bearing aquifer, and penetration of the top and bottom aquitards is strictly prohibited. Figure 2 As shown.

[0052] Numerical simulation was employed, using MODFLOW for flow field calculations and a corresponding MODPATH particle tracking module for simulating the leaching range. The locations of leaching channels were designed, with multiple channel lengths (3m, 5m, 8m, 10m, 15m) set to simulate the seepage field and injection-production pressure under different lengths and flow rates. The optimal injection and extraction flow rates for a single well were determined through simulation, ensuring that the upper limit of the injection pressure did not exceed 80% of the formation fracturing pressure and the lower limit of the pumping dynamic water level was not lower than the maximum elevation of the top plate of the mineralized aquifer, guaranteeing an injection-production balance rate of ≥80%. Finally, the top and bottom depths of the leaching channels and the affected area of ​​a single well were determined, providing a fundamental basis for designing the well spacing of integrated injection-extraction leaching production wells.

[0053] Based on the optimization of single-well parameters, a numerical model at the well group scale is constructed. Combined with the planar distribution characteristics of the ore body, the well network form and well spacing are optimized to avoid mutual interference between the flow fields of adjacent wells, which could lead to short circuits or dead zones of dissolution. The ore body sweep rate within the well network control area is required to be ≥70%.

[0054] The fourth step is the construction of an integrated in-situ leaching production well for uranium extraction and injection.

[0055] Based on the simulation results, drilling operations will be carried out for integrated in-situ leaching uranium production wells: 1. First-stage drilling and surface casing cementing: Use a Φ311mm drill bit to drill to 3-5m above the aquitard of the mineralized aquifer. Run in a Φ244.5mm surface casing and inject G-grade oil well cement. The cement rises to the surface and is allowed to set for 48 hours. Then, conduct sonic logging to ensure that the surface casing completely seals the shallow unconfined layer. The cementing pass rate is 100%.

[0056] 2. Second-stage drilling and full-process logging: Using a Φ215.9mm drill bit, continue drilling from inside the surface casing to the designed well depth (3-5m beyond the bottom of the fluid extraction filter); the core recovery rate of the ore-bearing layer is ≥90%, and that of the non-ore-bearing layer is ≥80%. Simultaneously carry out drilling logging, core logging, mud logging, and gamma logging, and check the consistency of the formation and ore body location with the design model in real time. If formation anomalies are found, promptly provide feedback to optimize the design parameters.

[0057] 3. Well completion logging: After drilling to the designed well depth, conduct geophysical logging of the entire well section, including natural gamma, spontaneous potential, resistivity, well diameter, sonic transit time, and density logging, to accurately identify the ore body boundary, the lithology of the ore-bearing aquifer, and the integrity of the aquitard, and finally determine the actual installation depth of the filter and water-stop packer, and issue a well completion logging report.

[0058] 4. Casing prefabrication and wellbore structure installation Based on the parameters determined by the well completion logging, the production casing is prefabricated and installed on the surface. The well structure adopts a two-stage structure of "surface casing + production casing". The production casing is made of materials such as UPVC, fiberglass or seamless steel pipe according to the burial depth of the ore body to ensure that the casing material can meet the strength requirements under production conditions.

[0059] 5. Annular cementing and quality inspection Cementing operations were carried out on the production casing and the annulus. G-grade oil well cement was used to prepare cement slurry with a density controlled at 1.85-1.95 g / cm³. The cement slurry was injected into the casing and returned from the annulus to 20 m above the top plate of the mineralized aquifer, ensuring complete isolation of the annulus above the mineralized aquifer and preventing leaching fluid from flowing up the annulus and contaminating the upper formation.

[0060] After cementing is completed and allowed to set for 72 hours, sonic variable density logging is conducted throughout the well section to test the cementing quality. The cement must be well bonded, without any channeling or missing sections, and the cementing pass rate must be 100%.

[0061] 6. Based on numerical simulation results and well completion logging data, determine the location, number, length, and orientation of the leaching channels. The channels must completely correspond to the ore body occurrence section of the injection and extraction filters. According to the formation lithology, hardness, and clay content, hydraulic jet perforation technology should be given priority, while hydraulic slotting technology should be selected for plastic formations with high clay content.

[0062] 7. Installation of water-stop packer: Select a washable high-pressure packer (such as Y341 type, rated working pressure ≥15MPa, temperature resistance ≥60℃) and install it in the solid wall section between the injection section and the pumping section.

[0063] 8. Well cleaning A combination of air compressor well washing, piston well washing, and chemical well washing was used to carry out deep well washing in the injection section and the pumping section respectively, to remove the pollution of the formation by drilling fluid and cement slurry and to unclog the seepage channels; the well washing met the qualified standards: the sand content of the water was ≤0.01% and the water quality was clear.

[0064] 9. Inspection of the effectiveness of the leaching channel After construction is completed, pumping tests are conducted on the injection section and the pumping section respectively to determine the permeability coefficient in the near-well zone. The permeability coefficient in the near-well zone is required to be more than 1.5 times higher than the original permeability coefficient of the mineralized aquifer to confirm that the leaching channel construction is qualified and meets the seepage design requirements.

[0065] A single-well injection-extraction linkage test was conducted according to the design parameters. Clean water was injected into the injection section, and simultaneously extracted from the extraction section. Real-time monitoring of injection pressure, injection-production flow rate, wellhead water level, and effluent water quality was performed. Key verification indicators included: 1) Injection-production balance rate ≥ 98%, with no formation leakage; 2) There is no cross-contamination between the two sections, and no clean water is directly injected at the extraction end, confirming that there is no short circuit in the injection process; 3) The water level drawdown and flow rate were stable in three consecutive pumping tests, with a relative error of ≤10%; the water level fitting error was ≤30%, and the flow rate fitting error was ≤30%, ensuring that the model can accurately predict formation seepage behavior.

[0066] After construction is completed, leaching and mining will be carried out to recover uranium.

[0067] Although this application has been described in detail above with general descriptions and specific embodiments, some modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, such modifications or improvements made without departing from the spirit of this application are all within the scope of protection claimed in this application.

Claims

1. A uranium production well with integrated extraction and injection system, characterized in that, include: The wellbore includes an injection section, a solid wall section, and a pumping section, all of which are entirely within the ore body. The well includes a pumping pipe and an injection pipe, both installed within the wellbore. The lower end of the pumping pipe is independently connected to the pumping section, and the lower end of the injection pipe is independently connected to the injection section. A water-stopping seal is installed within the solid wall section.

2. The production well according to claim 1, characterized in that, The injection section and the extraction section are respectively provided with leaching channels, which are provided by water jetting, water jetting, or installing filters. The length of the leaching channels is 3-15m.

3. The production well according to claim 1, characterized in that, The length of the solid wall section is 1-10m, and the rated sealing pressure of the built-in water-stop packer is ≥1.2×maximum working injection pressure+existing static pressure.

4. A method for in-situ leaching mining of thick sandstone uranium ore bodies, characterized in that, The production well described in any one of claims 1-3 comprises the following steps: (1) Three-dimensional geological modeling: Combining the sequential Gaussian simulation method, the geological-ore body characteristic parameters and hydrogeological parameters are spatially mapped to establish a three-dimensional ore body model; (2) Construction of flow field numerical model: The hydrogeological parameters of the three-dimensional ore body model are spatially mapped to the numerical model grid, and the partition assignment is completed according to lithology and ore body distribution to construct a three-dimensional finite difference seepage numerical model. (3) The leaching channel design adopts the production well with integrated injection and extraction, and simulates and determines the start and end positions of the injection section and the extraction section of a single well, the optimal injection flow rate and extraction flow rate, and determines the effective leaching range of a single well, providing a basic basis for setting the well spacing of the production wells; (4) Construction of integrated extraction and injection uranium production wells and leaching mining.

5. The mining method according to claim 4, characterized in that, In step (1), the planar grid size is ≤10m×10m and the vertical single-layer thickness is ≤1m.

6. The mining method according to claim 5, characterized in that, The vertical single-layer thickness of the ore body section is ≤0.5m.

7. The mining method according to claim 4, characterized in that, In step (2), the planar grid within 20m of the production well is densified, and the grid size is ≤2m×2m.

8. The mining method according to claim 4, characterized in that, In step (3), the simulation determines that the injection pressure does not exceed 80% of the formation fracturing pressure, the pumping dynamic water level is not lower than the maximum elevation of the top plate of the ore-bearing aquifer, and ensures that the injection-production balance rate is ≥80% and the ore body sweep rate within the well network control range is ≥70%.

9. The mining method according to claim 4, characterized in that, In step (4), the construction process includes well drilling, well logging, casing installation, drilling and cementing, well logging verification, opening of the leaching channel, equipment installation, and well washing and inspection of the effect of the leaching channel.

10. The mining method according to claim 9, characterized in that, Well washing meets the qualified standards; the requirements for the effect of the leaching channel are as follows: the permeability coefficient in the near-well zone is more than 1.5 times higher than the original permeability coefficient of the mineralized aquifer; the drawdown and flow rate are stable in three consecutive pumping tests, with a relative error of ≤10%; the water level fitting error is ≤30% and the flow rate fitting error is ≤30%, ensuring that the model can accurately predict the formation seepage behavior; there is no cross-flow short circuit.

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