A method of in-situ leaching well distribution suitable for low permeability sandstone type uranium mine

Abstract

The application discloses a kind of suitable for low permeability sandstone type uranium deposit in-situ leaching well distribution method, belong to sandstone uranium deposit in-situ leaching mining technical field, first target mining area is geologically surveyed, and the spatial distribution range of ore-bearing layer is defined, then according to the main ore layer horizontal distribution range arrangement horseshoe horizontal well, and in horizontal well drop explosive implementation blasting, improve the permeability of ore bed, according to the impact fracturing range radius design horizontal well spacing and charge package installation interval, complete horizontal well well flushing, between horizontal well arrangement straight well, horizontal well injection, straight well pumping, straight well interval is most widely based on optimization design of leaching range.The application applies horseshoe well technology to low permeability sandstone uranium deposit in-situ leaching, and the horizontal section of horseshoe well is mainly used for blasting permeability, and injection leaching liquid, and straight well is used for extracting leaching liquid, through the reasonable arrangement of horseshoe well and straight well pumping injection well network, to improve the mining efficiency and recovery of uranium resources.

Description

Technical Field

[0001] This invention relates to the field of sandstone uranium leaching mining technology, and more specifically to a method for combined horseshoe-shaped and vertical well leaching of low-permeability sandstone uranium deposits. Background Technology

[0002] Uranium is a key raw material for nuclear power generation, and its efficient and environmentally friendly mining is crucial for energy security and sustainable development. Due to the unique reservoir characteristics of low-permeability sandstone uranium deposits, traditional mining methods face many challenges. In-situ leaching (ISL) technology has become the main means of mining this type of uranium deposit due to its environmental friendliness and cost advantages.

[0003] One effective way to improve the recovery rate of low-permeability sandstone-type uranium deposits is to increase the permeability of the ore layer, i.e., to modify the ore layer. Blasting fracturing is the most direct and effective method. The stress wave and explosive gas can effectively drive the propagation of rock cracks, forming a more uniform crack network, creating an environment for the uniform seepage of leaching solutions in the ore layer. At the same time, considering that uranium deposits are generally thin and widely distributed, the traditional five-point vertical shaft network mining has problems such as high well density, small ore control area per well, and large land area, resulting in a low overall return on investment.

[0004] To address the aforementioned problems, this invention applies horseshoe-shaped horizontal well technology to the field of in-situ leaching mining of uranium. Horseshoe-shaped wells are used for initial blasting and permeability enhancement of the reservoir. Subsequently, the horseshoe-shaped wells are used as injection wells to inject leaching fluid, while vertical wells are used as pumping wells for in-situ leaching mining of uranium. The well layout scheme is optimized and evaluated. Compared to the traditional five-point vertical well layout, this method is theoretically more suitable for uranium mining, and is an effective means to improve recovery rate and single-well production, possessing significant engineering importance. Summary of the Invention

[0005] In view of this, the technical solution of the present invention aims to provide a method for combined leaching of horseshoe-shaped wells and vertical wells suitable for low-permeability sandstone-type uranium deposits. The horseshoe-shaped wells can realize the functions of early-stage reservoir blasting and later-stage fluid injection, while the vertical wells are used to extract the leaching solution. By adjusting the spacing of the horizontal sections of the horseshoe-shaped wells and the spacing of the vertical wells, the leaching dead zones are reduced, maximizing the leaching range.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A method for in-situ leaching well placement suitable for low-permeability sandstone-type uranium deposits includes the following steps:

[0008] (1) Conduct geological exploration of the ore layer to obtain a refined three-dimensional geological model of the ore layer. Determine the length of the horizontal section of the horseshoe well according to the extension range of the target ore layer. Set up the blasting point location according to the blasting method. Design the horizontal section spacing L1 of a single horseshoe well and the horizontal section spacing L2 of two adjacent horseshoe wells based on the blasting stress wave damage range.

[0009] (2) Vertical wells are arranged at the center of the horizontal section of a single horseshoe well and at the center of the adjacent horizontal section of two horseshoe wells, respectively;

[0010] (3) Explosives are loaded at the locations in the horizontal section of the horseshoe well and the vertical well. The distance between the blasting points in the horseshoe well is L3, and the distance between the two vertical wells at the center of the horizontal section of the single horseshoe well is L4. The blasting points in the horizontal section of the horseshoe well and the blasting points in the vertical well form a five-point array on the same horizontal plane, and L1=L3=L4.

[0011] Preferably, the three-dimensional geological model in step (1) includes the strike, thickness, width, and spatial distribution range of the ore layer.

[0012] Preferably, in step (1), the distance L2 between adjacent horizontal sections of the two horseshoe wells is less than the distance L1 between horizontal sections of a single horseshoe well.

[0013] Preferably, the vertical well spacing at the center of the adjacent horizontal sections of two horseshoe wells is smaller than the vertical well spacing at the center of the horizontal sections of a single horseshoe well.

[0014] Preferably, explosives are loaded on both the upper and lower sides of the plane where the horseshoe-shaped well is located in the vertical well, and the amount of explosives loaded on the upper and lower sides is greater than the amount of explosives loaded at the plane where the horseshoe-shaped well is located.

[0015] Preferably, the explosive is an emulsion explosive, and the filling method is cylindrical filling.

[0016] As can be seen from the above technical solution, compared with the prior art, the present invention discloses a method for in-situ leaching well placement suitable for low-permeability sandstone-type uranium deposits, which has the following beneficial effects:

[0017] This invention employs horseshoe well technology for uranium leaching mining. Compared to the traditional five-point well layout method, this invention has significant advantages such as large injection volume, high sweep efficiency, and large leaching area per well; it can effectively reduce leaching dead zones and improve return on investment.

[0018] This invention enables a well to serve two purposes. First, it completes the blasting modification of the reservoir, with the horizontal well controlling the blasting range in the plane of the ore layer and the vertical well controlling the blasting range in the vertical plane. Then, it functions as a pumping and injection well, which improves both permeability and the ore control range of a single well.

[0019] This invention can effectively reduce the number of vertical wells. By rationally arranging vertical wells, efficient liquid extraction can be achieved, and the liquid extraction pressure can also be used to promote the migration of leaching liquid in the ore layer. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0021] Figure 1 A three-dimensional diagram of the well layout structure;

[0022] Figure 2 This is a horizontal cross-sectional view;

[0023] Figure 3 This is a vertical cross-sectional view;

[0024] In the diagram, 1-Injection end of horseshoe well; 2-Sealing end of horseshoe well; 3-Vertical well; 4-Blast point; Detailed Implementation

[0025] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0026] As attached Figure 1-3 The aforementioned in-situ leaching well placement method applicable to low-permeability sandstone-type uranium deposits includes the following steps:

[0027] (1) Conduct geological exploration of the ore layer to obtain a refined three-dimensional geological model of the ore layer, and obtain basic information such as the strike, thickness, and width of the ore layer and its spatial distribution range. Determine the length of the horizontal section of the horseshoe well according to the extension range of the target ore layer, and set the location of blasting point 4 according to the blasting method. Design the horizontal section spacing L1 of a single horseshoe well and the horizontal section spacing L2 of two adjacent horseshoe wells based on the blasting stress wave damage range (e.g., Figure 2 As shown, the distance L2 between adjacent horizontal sections of two horseshoe-shaped wells is smaller than the distance L1 between horizontal sections of a single horseshoe-shaped well. This distance can be optimized through multiple sets of experiments, with the widest possible leaching range as the optimization objective. A smaller L2 not only enhances the blasting effect between the horizontal sections of the two horseshoe-shaped wells but also compensates for the reduced permeability caused by the decrease in seepage pressure at the end of the horizontal section due to hydraulic pressure drop and energy loss. Simultaneously, the pumping pressure of the vertical shaft between the horizontal sections of the two horseshoe-shaped wells also promotes the migration of the leaching solution.

[0028] (2) Vertical wells 3 are arranged at the center of the horizontal section of a single horseshoe well and at the center of the adjacent horizontal section of two horseshoe wells respectively. The distance between the two vertical wells at the center of the horizontal section of a single horseshoe well is L4.

[0029] (3) Explosives are loaded at the locations in the horizontal section of the horseshoe well and vertical well 3, with the blasting point spacing in the horseshoe well being L3. The blasting points in the horizontal section of the horseshoe well and the blasting points in vertical well 3 form a five-point array on the same horizontal plane (e.g., Figure 2 (as shown in the structure), and L1=L3=L4, to ensure that the cracks overlap and penetrate.

[0030] In some specific implementation technical solutions, the vertical well spacing 3 at the center of the adjacent horizontal sections of two horseshoe wells is smaller than the vertical well spacing L4 at the center of the horizontal sections of a single horseshoe well, in order to adapt to the problem of decreased injection pressure at the end of the horizontal section of the horseshoe well.

[0031] In some specific implementation technical solutions, such as Figure 3 As shown, explosives are loaded on both the upper and lower sides of the plane where the horseshoe-shaped well horizontal section is located in vertical well 3, and the amount of explosives on the upper and lower sides is greater than the amount of explosives at the position where the horseshoe-shaped well horizontal section is located, so as to obtain a uniform and interconnected fracture network.

[0032] In some specific implementation solutions, the explosive is an emulsion explosive, and the filling method is cylindrical filling.

[0033] The specific principle of the above technical solution is as follows: First, the horseshoe-shaped horizontal wells and vertical wells are used as blasting wells. Explosives are rationally arranged according to geological conditions to blast the target ore layer, obtaining a relatively uniform fracture network, which facilitates the uniform seepage of the leaching solution during subsequent leaching mining. A blasting scheme is designed based on the geological conditions, and the explosive blasting points arranged in the horseshoe-shaped horizontal and vertical wells form a spatial lattice structure, uniformly covering the target ore layer. Second, after the blasting of the ore layer is completed, the well conditions are checked, and well washing is carried out if necessary. Then, the horseshoe-shaped horizontal wells are used as injection wells, with one end injected (injection end 1) and the other end sealed (sealed end 2). The vertical wells are used as pumping wells. The reason for adding a row of vertical wells between the two horseshoe-shaped horizontal wells is to consider the hydraulic pressure drop during the flow of the leaching solution along the horseshoe-shaped horizontal wells. The permeability weakens between the two horseshoe-shaped horizontal wells, and adding vertical pumping wells can remedy this problem.

[0034] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0035] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for in-situ leaching well placement suitable for low-permeability sandstone-type uranium deposits, characterized in that, Includes the following steps: (1) Conduct geological exploration of the ore layer to obtain a refined three-dimensional geological model of the ore layer. The three-dimensional geological model includes the strike, thickness, width and spatial distribution range of the ore layer. Determine the length of the horizontal section of the horseshoe well according to the extension range of the target ore layer. Arrange the blasting point positions according to the blasting method. Design the horizontal section spacing L1 of a single horseshoe well and the horizontal section spacing L2 of two adjacent horseshoe wells based on the blasting stress wave damage range, where L2 < L1. (2) Vertical wells are arranged at the center of the horizontal section of a single horseshoe well and at the center of the adjacent horizontal section of two horseshoe wells, respectively, and the distance between the vertical wells at the center of the adjacent horizontal section of two horseshoe wells is less than the distance between the vertical wells at the center of the horizontal section of a single horseshoe well. (3) Explosives are loaded at the locations in the horizontal section of the horseshoe well and the vertical well. The distance between the blasting points in the horseshoe well is L3, and the distance between the two vertical wells at the center of the horizontal section of the single horseshoe well is L4. The blasting points in the horizontal section of the horseshoe well and the blasting points in the vertical well form a five-point array on the same horizontal plane, and L1=L3=L4.

2. The in-situ leaching well placement method suitable for low-permeability sandstone-type uranium deposits according to claim 1, characterized in that, Explosives are loaded on both the upper and lower sides of the plane where the horseshoe-shaped well is located in the vertical well, and the amount of explosives loaded on the upper and lower sides is greater than the amount of explosives loaded at the plane where the horseshoe-shaped well is located.

3. The in-situ leaching well placement method suitable for low-permeability sandstone-type uranium deposits according to claim 1, characterized in that, The explosive is an emulsion explosive, and the filling method is cylindrical filling.

Images