An in-situ leaching uranium mining directional drilling wellbore structure and method

Abstract

The application provides a kind of in-situ leaching uranium directional drilling wellbore structure and method, belonging to the technical field of in-situ leaching uranium well completion, comprising: straight well section casing, build-up section casing, horizontal section screen pipe and anti-extraction pipe, the wellbore adopts split type composite structure, different material casings are reasonably compounded to improve the overall strength of each section casing in the wellbore, avoid casing damage, improve the support strength and structural stability of the wellbore, and at the same time reduce the possibility of corrosion damage of the wellbore; the horizontal section screen pipe is embedded in the build-up section casing after passing through the anti-extraction pipe, the horizontal section screen pipe and the build-up section casing are connected and fixed through the anti-extraction pipe, to prevent displacement of the horizontal section screen pipe, and make the connection end of the horizontal section screen pipe a double-layer structure, the anti-extraction pipe supports and protects the internal horizontal section screen pipe to improve the connection reliability of the horizontal section screen pipe and the build-up section casing.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of in-situ leaching uranium well completion, and particularly relates to an in-situ leaching uranium directional drilling well structure and method. BACKGROUND

[0002] In-situ leaching uranium is a commonly used uranium mining method, and its principle is to inject a leaching agent to chemically react with uranium minerals in a uranium ore layer, so that the uranium minerals are dissolved and then taken to the ground through liquid pumping. The conventional directional drilling well is prone to aging and damage during the in-situ leaching process, which destroys the original components of the leaching liquid, affects the service life of the mine, and increases the subsequent hydrometallurgical operation cost. SUMMARY

[0003] The present application aims to at least solve one of the problems in the prior art or related art.

[0004] To this end, the first aspect of the application provides an in-situ leaching uranium directional drilling well structure.

[0005] The second aspect of the application provides an in-situ leaching uranium method.

[0006] Therefore, according to the first aspect of the embodiments of the present application, an in-situ leaching uranium directional drilling well structure is provided, comprising:

[0007] A straight section casing is arranged in the straight section along the length direction of the straight section;

[0008] A build-up section casing is arranged in the build-up section, and a first end of the build-up section casing is connected with the straight section casing;

[0009] A horizontal section screen pipe is arranged in the horizontal section along the length direction of the horizontal section, and a first end of the horizontal section screen pipe is embedded in a second end of the build-up section casing;

[0010] A pipe guard is arranged outside the horizontal section screen pipe, and the pipe guard is connected with the second end of the build-up section casing to limit the horizontal section screen pipe through the pipe guard.

[0011] In a feasible implementation, the in-situ leaching uranium directional drilling well structure further comprises:

[0012] A packer is sleeved outside the horizontal section screen pipe, the packer is located between the horizontal section screen pipe and the pipe guard, and the packer fills an annular gap between the horizontal section screen pipe and the pipe guard to fix the horizontal section screen pipe in the pipe guard.

[0013] In a feasible implementation, the straight section casing is made of polyvinyl chloride or hard polyvinyl chloride material, the build-up section casing is made of glass fiber reinforced plastic material, the pipe guard is made of glass fiber reinforced plastic material, and the packer is made of stainless steel material.

[0014] In an implementable embodiment, the in-situ leaching uranium directional drilling wellbore structure further comprises:

[0015] an adapter casing, a first end of the adapter casing being threadedly connected with the vertical section casing, and a second end of the adapter casing being threadedly connected with the build-up section casing;

[0016] wherein the first end of the adapter casing is provided with a first internal thread, and the second end of the adapter casing is provided with a first external thread.

[0017] In an implementable embodiment, the anti-disengagement pipe comprises:

[0018] a main body, the main body being a hollow cavity with openings at both ends;

[0019] a first thread, the first thread being arranged on an inner wall of a first end of the main body, and the main body being threadedly connected with the build-up section casing through the first thread;

[0020] a stepped groove, the stepped groove being arranged on the inner wall of the main body along a circumferential direction of the main body, and the stepped groove being matched with an outer wall of the packer;

[0021] an anti-disengagement opening, the anti-disengagement opening being arranged at a second end of the main body, and the horizontal section screen pipe being interference-fitted with the anti-disengagement opening;

[0022] a guide opening, the guide opening being located between the anti-disengagement opening and the stepped groove, the guide opening being connected with the anti-disengagement opening, and an inner diameter of the guide opening gradually increasing from an end close to the anti-disengagement opening to an end away from the anti-disengagement opening.

[0023] According to a second aspect of the embodiments of the present application, an in-situ leaching uranium method is provided, which is applied to the in-situ leaching uranium directional drilling wellbore structure according to any of the above technical solutions, and comprises:

[0024] drilling a vertical well, after a vertical casing is lowered into the vertical well, mud is injected in a reverse direction, and after the mud is solidified, a window is cut in a uranium ore layer section to form a vertical annulus space;

[0025] drilling a vertical section and a build-up section of a horizontal well, and sequentially lowering an anti-disengagement pipe, a build-up section casing, an adapter casing, and a vertical section casing, and cementing the well with mud;

[0026] drilling a horizontal section of the horizontal well, and adjusting a trajectory in real time to make a tail end of the horizontal section butt against the vertical annulus space;

[0027] sending a horizontal section screen pipe into the horizontal section, and fixing the horizontal section screen pipe in the anti-disengagement pipe;

[0028] lowering a liquid injection pipe from a wellhead of the vertical section, and sealing the wellhead of the vertical section;

[0029] injecting a leaching liquid from the liquid injection pipe, the leaching liquid permeating to the uranium ore layer through the horizontal section screen pipe, and after the leaching liquid dissolves uranium ore, leaching liquid is lifted to the ground.

[0030] In one possible implementation, the straight section and the build-up section of the horizontal well are drilled, and a slip-proof pipe, a build-up section casing, a switching casing and a straight section casing are sequentially lowered, and cementing is performed by mud, including the steps of:

[0031] drilling the straight section and the build-up section of the horizontal well in open hole;

[0032] performing well trajectory logging and hole diameter logging on the horizontal well;

[0033] performing punching treatment on the horizontal well after the well logging is qualified;

[0034] sequentially lowering the slip-proof pipe, the build-up section casing, the switching casing and the straight section casing, and then performing cementing by mud.

[0035] In one possible implementation, the horizontal section of the horizontal well is drilled, and the trajectory is adjusted in real time, so that the tail end of the horizontal section is docked with the annular space of the straight well, including the steps of:

[0036] drilling the horizontal section by using directional drilling technology, and performing uranium layer logging and drilling guidance during the drilling;

[0037] adjusting the well trajectory of the horizontal section according to the actual distribution of the uranium layer, so that the tail end of the horizontal section is docked with the annular space of the straight well;

[0038] installing the horizontal section screen pipe on the drilling tool, and slowly feeding the horizontal section screen pipe into the horizontal section through the drilling tool;

[0039] during the broadcasting of the horizontal section screen pipe, high-pressure punching is performed, and liquid is pumped from the process straight well to dredge the well hole of the horizontal section;

[0040] after the horizontal section screen pipe reaches the designed position in the horizontal section, the horizontal section screen pipe is fixed by setting and sealing in the slip-proof pipe through the packer.

[0041] In one possible implementation, a liquid injection pipe is lowered from the wellhead of the straight section, and the wellhead of the straight section is sealed, including the steps of:

[0042] before liquid injection, the downhole part of the process straight well is sealed by a sealing device, so that the pressure resistance of the part below the sealed section exceeds the designed injection pressure;

[0043] lowering the liquid injection pipe from the wellhead of the horizontal well, installing a sealing device at the wellhead of the horizontal well, sealing the annular gap between the liquid injection pipe and the straight section casing, and performing sealing test.

[0044] In one possible implementation, the method further includes:

[0045] injecting chemical washing fluid into the wellbore, sealing and soaking for 24h-72h to remove chemical blockages near the horizontal section screen pipe;

[0046] After the soaking is completed, the turbid liquid in which the chemical blocking material is dissolved is pumped out through the process straight well;

[0047] The high pressure injects the degradable flushing fluid into the wellbore, and the liquid is pumped through the process straight well;

[0048] The suspended solids in the degradable flushing fluid are filtered, and the flushing is continuously circulated for 24-72 hours to remove the accumulated sand blocking material in the horizontal section screen pipe and the wellbore.

[0049] Compared with the prior art, the in-situ leaching uranium directional drilling wellbore structure and method provided by the application has the beneficial effects that:

[0050] The in-situ leaching uranium directional drilling wellbore structure provided by the embodiment of the application includes a straight well section casing, a build-up section casing, a horizontal section screen pipe and an anti-extraction pipe, the wellbore adopts a split composite structure, different material casings are reasonably combined to improve the overall strength of the casings in each section of the wellbore, avoid damage to the casing, improve the support strength and structural stability of the wellbore, and reduce the possibility of corrosion damage to the wellbore; the horizontal section screen pipe is embedded in the build-up section casing after passing through the anti-extraction pipe, the horizontal section screen pipe and the build-up section casing are connected and fixed through the anti-extraction pipe, displacement of the horizontal section screen pipe is prevented, and the connection end of the horizontal section screen pipe is a double-layer structure, the internal horizontal section screen pipe is supported and protected by the anti-extraction pipe, so as to improve the connection reliability of the horizontal section screen pipe and the build-up section casing. BRIEF DESCRIPTION OF DRAWINGS

[0051] Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The detailed description is made with reference to the accompanying drawings.

[0052] Figure 1 A schematic structural diagram of the in-situ leaching uranium directional drilling wellbore structure provided by an embodiment of the application during construction;

[0053] Figure 2 A schematic structural diagram of the adapter casing of the in-situ leaching uranium directional drilling wellbore structure provided by an embodiment of the application;

[0054] Figure 3 A schematic structural diagram of the anti-extraction pipe of the in-situ leaching uranium directional drilling wellbore structure provided by an embodiment of the application;

[0055] Figure 4 A schematic structural diagram of the in-situ leaching uranium directional drilling wellbore structure provided by an embodiment of the application during liquid injection;

[0056] Figure 5A schematic structural diagram of a wash well of a directional drilling well structure of an in-situ leaching uranium mining method provided in an embodiment of the present application;

[0057] Figure 6 A schematic step flow structure diagram of an in-situ leaching uranium mining method provided in an embodiment of the present application;

[0058] Correspondence between reference signs and component names in the drawings is as follows: Figures 1 to 5

[0059] 1, straight well section casing; 2, build-up section casing; 3, horizontal section screen pipe; 4, anti-dropping pipe; 5, packer; 6, adapter casing; 7, first internal thread; 8, first external thread;

[0060] 22, straight well section; 23, build-up section; 24, horizontal section; 25, process straight well casing; 26, straight well annulus space; 27, liquid injection pipe; 28, sealing device; 29, sealing device; 30, lifting device; 31, uranium ore layer; 32, ore layer annulus space;

[0061] 41, main body; 42, first thread; 43, stepped groove; 44, anti-dropping port; 45, guide port. DETAILED DESCRIPTION

[0062] In the description of the present application, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0063] In addition, the terms "first" and "second" are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with "first" and "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise specifically limited.

[0064] ​In this application, unless specifically defined and limited otherwise, the terms "mounting", "connected", "connecting", "fixed", and the like, should be interpreted broadly, for example, can be fixed connection, can also be detachable connection, or integrally connected; can be mechanical connection, can also be electrical connection; can be directly connected, can also be indirectly connected through an intermediate medium, can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0065] The preferred embodiments of the present application are described below in conjunction with the accompanying drawings, it should be understood that the preferred embodiments described here are only used to illustrate and explain the present application, and are not used to limit the present application.

[0066] As Figure 1 shown, according to the first aspect of the embodiments of the present application, a directional drilling wellbore structure for in-situ leaching of uranium is provided, comprising: a straight section casing 1, a build-up section casing 2, a horizontal section screen pipe 3 and a anti-extraction pipe 4, the straight section casing 1 is arranged in the straight section 22 along the length direction of the straight section 22; the build-up section casing 2 is arranged in the build-up section 23, the first end of the build-up section casing 2 is connected with the straight section casing 1; the horizontal section screen pipe 3 is arranged in the horizontal section 24 along the length direction of the horizontal section 24, the horizontal section screen pipe 3 forms a ore bed annular space 32 with the horizontal section 24, the first end of the horizontal section screen pipe 3 is embedded in the second end of the build-up section casing 2; the anti-extraction pipe 4 is arranged outside the horizontal section screen pipe 3, the anti-extraction pipe 4 is connected with the second end of the build-up section casing 2 to limit the horizontal section screen pipe 3 through the anti-extraction pipe 4.

[0067] The directional drilling wellbore structure for in-situ leaching of uranium provided by the embodiments of the present application includes the straight section casing 1, the build-up section casing 2, the horizontal section screen pipe 3 and the anti-extraction pipe 4, the wellbore adopts a split type composite structure, different material casings are reasonably combined to improve the overall strength of the casings in the wellbore, avoid the damage of the casing, improve the support strength and structural stability of the wellbore, and reduce the possibility of corrosion damage of the wellbore; the horizontal section screen pipe 3 is embedded in the build-up section casing 2 after passing through the anti-extraction pipe 4, the horizontal section screen pipe 3 is connected and fixed with the build-up section casing 2 through the anti-extraction pipe 4, to prevent the displacement of the horizontal section screen pipe 3 in the horizontal section 24, and make the connection end of the horizontal section screen pipe 3 be a double-layer structure, the anti-extraction pipe 4 is used to support and protect the internal horizontal section screen pipe 3, to improve the connection reliability of the horizontal section screen pipe 3 and the build-up section casing 2.

[0068] Further, the length of the vertical section casing 1 is determined according to the depth of the vertical section 22 of the horizontal well, the vertical section casing 1 vertically extends from the wellhead of the vertical section 22 to the starting point of the build-up section 23; the length of the horizontal section screen pipe 3 covers the range of the target uranium ore layer 31; the shape of the build-up section casing 2 matches the shape of the build-up section 23 of the horizontal well, the curvature of the curved part of the build-up section casing 2 is consistent with the curvature of the trajectory of the build-up section 23, which ensures that the build-up section casing 2 can smoothly enter the horizontal section 24 from the build-up section 23.

[0069] As shown in Figure 1 In a feasible implementation, the in-situ leaching uranium directional drilling well structure further comprises a packer 5, the packer 5 is sleeved outside the horizontal section screen pipe 3, the packer 5 is located between the horizontal section screen pipe 3 and the anti-falling pipe 4, and the packer 5 fills the annular gap between the horizontal section screen pipe 3 and the anti-falling pipe 4 to fix the horizontal section screen pipe 3 in the anti-falling pipe 4.

[0070] In this technical solution, the packer 5 is sleeved on the horizontal section screen pipe 3, the packer 5 is embedded in the anti-falling pipe 4, the packer 5 seals the annular gap between the horizontal section screen pipe 3 and the anti-falling pipe 4, prevents the leaching liquid from directly entering the annular gap, and ensures the directional penetration of the leaching liquid from the horizontal section screen pipe 3 to the uranium ore layer 31; at the same time, the horizontal section screen pipe 3 is fixedly connected in the anti-falling pipe 4 through the packer 5, which supports and fixes the horizontal section screen pipe 3 to ensure the connection stability of the horizontal section screen pipe 3 and the build-up section casing 2.

[0071] In some examples, the horizontal section screen pipe 3 is anchored by hydraulic or mechanical setting to seal the annular gap between the build-up section casing 2 and the horizontal section screen pipe 3, thereby resisting the flow impact of the leaching liquid.

[0072] As a preferred solution, the packer 5 is made of stainless steel material with a pressure rating ≥15MPa to ensure no leakage under the designed injection pressure.

[0073] In a feasible implementation, the vertical section casing 1 is made of polyvinyl chloride or hard polyvinyl chloride material; the build-up section casing 2 is made of glass steel material; the anti-falling pipe 4 is made of glass steel material; and the packer 5 is made of stainless steel material.

[0074] In this technical solution, the vertical well casing 1 is made of polyvinyl chloride or rigid polyvinyl chloride, which is low in cost and resistant to chemical corrosion; the directional drilling casing 2 and the anti-derailment casing 4 are made of high-strength fiberglass, giving them a high strength-to-weight ratio and greater bending strength. The vertical well casing 1 and the directional drilling casing 2 are made of different materials, which improves the wellbore's support capacity while ensuring its corrosion resistance; the packer 5 is made of stainless steel, which is resistant to high-pressure corrosion and reduces the risk of brittle fracture at the anchoring point of the horizontal section screen pipe 3 on the anti-derailment casing 4, ensuring the overall pressure resistance of the wellbore; appropriate anti-corrosion materials are selected for each location in the wellbore, which improves the wellbore's corrosion resistance while ensuring its strength and support capacity, thus helping to extend the wellbore's service life and reduce maintenance costs.

[0075] In some examples, the vertical well casing 1 is made of rigid polyvinyl chloride (PVC), with an outer diameter of 152 mm to 190 mm and a wall thickness of 8 mm to 16 mm. As a preferred embodiment, the outer diameter of the vertical well casing 1 is 190 mm and the wall thickness is 16 mm.

[0076] The directional drilling casing 2 is made of fiberglass, with an outer diameter of 152mm to 190mm and a wall thickness of 8mm to 16mm. As a preferred option, the outer diameter of the directional drilling casing 2 is 190mm, and the wall thickness of the vertical well casing 1 is 16mm.

[0077] Furthermore, the horizontal section screen tube 3 is made of reinforced fiberglass material. The outer diameter of the horizontal section screen tube 3 matches the inner diameter of the inclined section sleeve 2. The wall thickness of the horizontal section screen tube 3 is 15mm to 20mm. The surface of the horizontal section screen tube 3 is uniformly provided with parallel filter slits. The slit width is 0.4mm to 0.6mm, the slit length is 50mm, and the slit spacing is 10mm.

[0078] like Figure 2 As shown, in one feasible embodiment, the wellbore structure for directional drilling of uranium mining by in-situ leaching further includes: a transition sleeve 6, the first end of which is threadedly connected to the vertical well section sleeve 1, and the second end of which is threadedly connected to the directional well section sleeve 2; wherein, the first end of the transition sleeve 6 is provided with a first internal thread 7, and the second end of the transition sleeve 6 is provided with a first external thread 8.

[0079] In this technical solution, both the vertical well casing 1 and the directional drilling casing 2 are threadedly connected to the adapter casing 6. The adapter casing 6 connects the vertical well casing 1 and the directional drilling casing 2 to avoid interface leakage caused by the difference in the expansion coefficients of the vertical well casing 1 and the directional drilling casing 2, thereby achieving an effective connection between the vertical well casing 1 and the directional drilling casing 2 made of different materials.

[0080] like Figure 3As shown, in one feasible embodiment, the anti-detachment tube 4 includes: a main body 41, a first thread 42, a stepped groove 43, an anti-detachment port 44, and a guide port 45; the main body 41 is a hollow cavity with openings at both ends; the first thread 42 is disposed on the inner wall of the first end of the main body 41, and the main body 41 is threadedly connected to the inclined section sleeve 2 through the first thread 42; the stepped groove 43 is disposed on the inner wall of the main body 41 along the circumference, and the stepped groove 43 is fitted with the outer wall of the packer 5; the anti-detachment port 44 is disposed at the second end of the main body 41, and the horizontal section screen tube 3 is interference-fitted with the anti-detachment port 44; the guide port 45 is located between the anti-detachment port 44 and the stepped groove 43, and the guide port 45 is connected to the anti-detachment port 44, and the inner diameter of the guide port 45 gradually increases from the end closer to the anti-detachment port 44 to the end farther away from the anti-detachment port 44.

[0081] In this technical solution, the anti-detachment tube 4 forms a double anti-detachment structure by setting a stepped groove 43, an anti-detachment port 44, and a guide port 45: the anti-detachment tube 4 engages with the external thread of the packer 5 through the stepped groove 43, making the packer 5 and the anti-detachment tube 4 self-locking, improving the pull-out resistance of the packer 5, and preventing the packer 5 from shifting in the axial direction of the anti-detachment tube 4, thereby ensuring the relative position stability between the horizontal section screen tube 3 and the anti-detachment tube 4, and ensuring the stability of the horizontal section screen tube 3; the horizontal section screen tube 3 is interference-fitted with the anti-detachment port 44 to prevent the horizontal section screen tube 3 from sliding axially; the horizontal section screen tube 3 is installed from the end of the anti-detachment tube 4 that connects to the directional section casing 2, and the guide port 45 plays a guiding role when the horizontal section screen tube 3 is installed, ensuring that the horizontal section screen tube 3 smoothly enters the anti-detachment port 44, avoiding jamming when the horizontal section screen tube 3 is sent in, and ensuring the construction efficiency of the wellbore.

[0082] like Figure 1 As shown, in one feasible embodiment, the wellbore structure of the directional drilling for in-situ leaching uranium mining further includes: a process vertical well, a vertical well section 22 parallel to the horizontal well, a vertical well annulus space 26 provided on the process vertical well, a horizontal section 24 connected to the vertical well annulus space 26, and a screen pipe 3 of the horizontal section extending into the vertical well annulus space 26.

[0083] In this technical solution, the process vertical well serves as an auxiliary wellbore, allowing for the creation of a vertical well annulus space 26 through openings in the uranium ore layer 31. This facilitates the precise deployment and docking of the horizontal section 24 of the horizontal well with the horizontal section screen pipe 3, avoiding direct disturbance of the uranium ore layer 31 during horizontal well construction and reducing the risk of wellbore collapse. Furthermore, the vertical well annulus space 26 provides a buffer zone, reducing stress concentration in the build-up section 23 and the horizontal section 24, helping to prevent the horizontal section screen pipe 3 from detaching. A process vertical well casing 25 is installed within the process vertical well, serving as a fluid circulation node during subsequent injection. During horizontal well construction, the process vertical well is used to pump out sediment from the collapsed wellbore, ensuring the smooth deployment of the horizontal section screen pipe 3 in the horizontal section 24. During well washing and maintenance, the process vertical well acts as a pumping channel, removing dissolved blockages within the uranium ore layer 31.

[0084] As Figure 4 shown, in a feasible implementation, the in-situ leaching uranium directional drilling wellbore structure further comprises: a liquid injection pipe 27 and a sealing device 28; the liquid injection pipe 27 is arranged in the straight well section 22, and the liquid injection pipe 27 is sealed with the well mouth of the straight well section 22 by a sealing device 29; the process straight well is provided with the sealing device 28, which blocks the process straight well during liquid injection.

[0085] In the technical solution, during the liquid injection process, the liquid injection pipe 27 is lowered and the horizontal well is sealed by the sealing device 29, and the sealing device 28 blocks the process straight well to form a sealed section in the process straight well, so as to prevent the leaching liquid from leaking or upward flowing to the straight well annulus space 26 during the liquid injection process, ensure the directional flow of the leaching liquid to the uranium ore bed 31, prevent the leakage of well pressure, ensure the uniform penetration of the leaching liquid to the uranium ore bed 31, and ensure the dissolution efficiency of the uranium ore; by sealing the wellbore, the return flow or leakage of the leaching liquid from the process straight well to the non-target area is prevented, the composition of the leaching liquid is prevented from being damaged and the leaching effect is prevented from being reduced, the dissolution efficiency is improved, and the service life of the wellbore is prolonged.

[0086] As Figure 5 shown, in a feasible implementation, the in-situ leaching uranium directional drilling wellbore structure further comprises: a lifting device 30, which is arranged in the process straight well along the length direction of the process straight well.

[0087] In the technical solution, during the well flushing process, the lifting device 30 is arranged in the process straight well to perform the liquid injection and extraction operation of well flushing; during the well flushing, the high-pressure well flushing liquid is injected into the horizontal well, and the process straight well extracts liquid, the lifting device 30 extends into the straight well annulus space 26 to lift the blockage to the ground surface, so as to prevent the blockage from accumulating in the horizontal section 24 and the straight well annulus space 26.

[0088] As Figure 6 shown, according to the second aspect of the present application, an in-situ leaching uranium method is provided, which is applied to the in-situ leaching uranium directional drilling wellbore structure in any of the above technical solutions, and the method comprises:

[0089] Step 100: drilling the process straight well, after the straight well casing is lowered in the process straight well, the mud is injected in reverse, and after the mud is solidified, the window is cut in the uranium ore bed 31 section to form the straight well annulus space 26;

[0090] Step 200: drilling the straight well section 22 and the build-up section 23 of the horizontal well, and sequentially lowering the anti-dropping pipe 4, the build-up section casing 2, the adapter casing 6 and the straight well section casing 1, and cementing the well with mud;

[0091] Step 300: drilling the horizontal section 24 of the horizontal well, and adjusting the trajectory in real time to make the tail end of the horizontal section 24 butt against the straight well annulus space 26;

[0092] Step 400: send the horizontal section screen pipe 3 into the horizontal section 24, and fix the horizontal section screen pipe 3 in the anti-dropping pipe 4;

[0093] Step 500: lower the injection pipe 27 from the wellhead of the vertical section 22, and seal the wellhead of the vertical section 22;

[0094] Step 600: inject the leaching solution from the injection pipe 27, and the leaching solution penetrates into the uranium ore bed 31 through the horizontal section screen pipe 3; after the leaching solution dissolves the uranium minerals, the leaching solution is lifted to the ground from the drillings of the well site except the horizontal well and the process vertical well.

[0095] Through the in-situ leaching method for uranium mining provided by the embodiment, the process vertical well is first constructed, so as to cut out the vertical well annular space 26 in the uranium ore bed 31 section, then the vertical section 22 and the build-up section 23 of the horizontal well are constructed, and the anti-dropping pipe 4, the build-up section casing 2, the adapter casing 6 and the vertical section casing 1 are sequentially sent in; the horizontal section 24 is constructed, so as to butt the horizontal section 24 with the vertical well annular space 26, and form the directional leaching channel; then the horizontal section screen pipe 3 is sent in, and the horizontal section screen pipe 3 is connected with the anti-dropping pipe 4, so as to accurately inject the leaching solution into the uranium ore bed 31 through the horizontal section screen pipe 3, and then lift the leaching solution to the ground from the other drillings of the well site.

[0096] Further, when the wellbore is cleaned and maintained in the later period, the process vertical well forms negative pressure by pumping liquid from the lifting pipe, so as to improve the well flushing efficiency, lift the well flushing blockage to the ground for collection and treatment, and guarantee the injection and leaching effect of the horizontal section 24.

[0097] In a feasible embodiment, the vertical section 22 and the build-up section 23 of the horizontal well are drilled, and the anti-dropping pipe 4, the build-up section casing 2, the adapter casing 6 and the vertical section casing 1 are sequentially lowered, and the well is cemented with mud, including the steps that: the vertical section 22 and the build-up section 23 are drilled in the open hole; the well trajectory and the well diameter of the horizontal well are measured; after the horizontal well is qualified by the well measurement, the horizontal well is treated by punching; the anti-dropping pipe 4, the build-up section casing 2, the adapter casing 6 and the vertical section casing 1 are sequentially lowered, and then the well is cemented with mud.

[0098] In the technical scheme, the well wall is stabilized by the open hole measurement, punching and pipe cementing; the collapsed section is identified by the well diameter measurement, so as to save the amount of cementing mud by targeted cementing in the subsequent process.

[0099] In a feasible implementation, the horizontal section 24 of the horizontal well is drilled, and the trajectory is adjusted in real time so that the tail end of the horizontal section 24 is connected with the annular space 26 of the vertical well, including the following steps: the drilling of the horizontal section 24 is performed by using the directional drilling technology, the logging of the uranium ore layer 31 and the drilling guiding are performed during the drilling, the well trajectory of the horizontal section 24 is adjusted according to the actual distribution of the uranium ore layer 31, so that the tail end of the horizontal section 24 is connected with the annular space 26 of the vertical well, the horizontal section screen pipe 3 is installed on the drilling tool, and the horizontal section screen pipe 3 is slowly sent into the horizontal section 24 through the drilling tool, the well hole of the horizontal section 24 is dredged by high-pressure punching and liquid pumping from the process vertical well during the broadcasting of the horizontal section screen pipe 3, and the horizontal section screen pipe 3 is fixed in the anti-dropping pipe 4 by the packer 5 after the horizontal section screen pipe 3 reaches the designed position in the horizontal section 24.

[0100] In the technical scheme, the trajectory of the horizontal section 24 is corrected in real time by logging, so as to improve the drilling rate of the uranium ore layer 31 of the horizontal section 24, after high-pressure punching, the sand is pumped out under negative pressure, then the horizontal section screen pipe 3 is sent into the horizontal section 24 by using the drilling tool, and is fixed in the anti-dropping pipe 4 by the packer 5, so as to avoid the axial displacement of the horizontal section screen pipe 3, and further avoid the short circuit of the liquid injection caused by the vibration and falling of the horizontal section screen pipe 3.

[0101] Further, the well hole of the horizontal section 24 is dredged by high-pressure punching during the broadcasting of the horizontal section screen pipe 3, the screw pump is used to continuously pump liquid in the process vertical well, so that the negative pressure is formed between the process vertical well and the horizontal section 24, the collapsed or deposited sand in the well wall is continuously pumped out, the negative pressure is used to pump and discharge the sludge when the horizontal section screen pipe 3 is lowered, the broadcasting of the horizontal section screen pipe 3 is smooth without blockage, and the horizontal section screen pipe 3 can be quickly installed in place.

[0102] In a feasible implementation, the liquid injection pipe 27 is lowered from the well mouth of the vertical well section 22, and the well mouth of the vertical well section 22 is sealed, including the following steps: before liquid injection, the downhole part of the process vertical well is sealed by the packer 28, so that the pressure resistance of the part below the sealed section exceeds the designed liquid injection pressure, the liquid injection pipe 27 is lowered from the well mouth of the horizontal well, the sealing device 29 is installed at the well mouth of the horizontal well to seal the annular gap between the liquid injection pipe 27 and the casing 1 of the vertical well section, and the sealing test is performed.

[0103] In the technical scheme, the sealing test is performed before liquid injection to ensure the reliability of the sealing before liquid injection, the process vertical well is blocked by the packer 28 to form a sealed section in the process vertical well, so as to prevent the leaching liquid from leaking or upward flowing to the annular space 26 of the vertical well during the liquid injection, ensure the directional flow of the leaching liquid to the uranium ore layer 31, prevent the leakage of the well pressure, improve the utilization rate of the leaching liquid, prevent the leakage of the high-pressure leaching liquid during the liquid injection, ensure the uniform penetration of the leaching liquid to the uranium ore layer 31, and ensure the dissolution efficiency of the uranium ore.

[0104] In a feasible implementation, the method further comprises: injecting a chemical flushing fluid into the wellbore, sealing and soaking for 24-72 hours to remove chemical blockages near the horizontal section screen pipe 3; after the soaking, pumping the turbidity containing the chemical blockages out through the process straight well; injecting a degradable flushing fluid into the wellbore under high pressure, and pumping through the process straight well; filtering the suspended solids in the degradable flushing fluid, and continuously circulating flushing for 24-72 hours to remove the accumulated silt blockages in the horizontal section screen pipe 3 and the wellbore.

[0105] In the technical solution, the weakly acidic chemical flushing fluid is injected to dissolve the calcium and magnesium scale, remove the chemical blockages near the horizontal section screen pipe 3, and restore the permeability; then the degradable flushing fluid is injected to mechanically and physically clean and carry out the accumulated silt in the horizontal section screen pipe 3 and the wellbore, thereby reducing the corrosion of the wellbore through active well flushing and prolonging the operation time of the uranium mine.

[0106] The in-situ leaching uranium mining method provided by the embodiments has all the beneficial effects of the in-situ leaching uranium mining directional drilling wellbore structure of the above technical solutions, and details are not repeated here.

[0107] Embodiment:

[0108] Taking a certain in-situ leaching uranium mining well as an example:

[0109] Well depth structure: straight well section 400 m, build-up section length 200 m, bending radius 130 m, horizontal section length 100 m.

[0110] Material parameters:

[0111] The straight well section casing is a PVC casing with an outer diameter of 190 mm, a wall thickness of 10 mm, and an internal pressure resistance of ≥6 MPa.

[0112] The build-up section casing is a glass steel casing with an outer diameter of 190 mm, a wall thickness of 14 mm, and an external extrusion strength of ≥20 MPa.

[0113] The horizontal section screen pipe is a glass steel screen pipe with an outer diameter of 152, a wall thickness of 20 mm, and an external extrusion strength of ≥16 MPa; it is a slit type with a single slit width of 0.6 mm, a slit length of 100 mm, and 40 slits per meter.

[0114] The wellbore structure continuously operates in a pH = 5 leaching agent for 1 year, and all the casings are free of corrosion perforation, and the horizontal section screen pipe does not displace or fall off.

[0115] Those skilled in the art can easily understand that the above embodiments can be freely combined and superimposed without conflict.

[0116] The above merely preferred embodiments of the present application are not used to limit the present application, any modification, equivalent replacement and improvement made within the spirit and principle of the present application should be included in the protection scope of the present application. The above is merely the preferred embodiment of the present application, it should be pointed out that, for the ordinary skilled in the art, without departing from the technical principle of the present application, a number of improvements and variations can be made, these improvements and variations should also be considered as the protection scope of the present application.

Claims

1. An in-situ leaching uranium mining directional drilling wellbore structure, characterized in that, The in-situ leaching uranium directional drilling wellbore structure comprises: a straight section casing arranged in the straight section along the length direction of the straight section; a build-up section casing arranged in the build-up section, the first end of the build-up section casing being connected with the straight section casing; a horizontal section screen pipe arranged in the horizontal section along the length direction of the horizontal section, the first end of the horizontal section screen pipe being embedded in the second end of the build-up section casing; an anti-extraction pipe arranged outside the horizontal section screen pipe, the anti-extraction pipe being connected with the second end of the build-up section casing to limit the horizontal section screen pipe through the anti-extraction pipe; a packer arranged outside the horizontal section screen pipe, the packer being located between the horizontal section screen pipe and the anti-extraction pipe; the anti-extraction pipe comprises: a main body being a hollow cavity with openings at both ends; a first thread arranged on the inner wall of the first end of the main body, the main body being threadedly connected with the build-up section casing through the first thread; a stepped groove arranged on the inner wall of the main body along the circumferential direction of the main body, the stepped groove being matched with the outer wall of the packer; an anti-extraction opening arranged at the second end of the main body, the horizontal section screen pipe being interference-fitted with the anti-extraction opening; a guide opening located between the anti-extraction opening and the stepped groove, the guide opening being connected with the anti-extraction opening, the inner diameter of the guide opening gradually increasing from the end close to the anti-extraction opening to the end away from the anti-extraction opening.

2. The in-situ leaching uranium directional drilling wellbore structure according to claim 1, wherein the packer fills the annular gap between the horizontal section screen pipe and the anti-extraction pipe, and fixes the horizontal section screen pipe in the anti-extraction pipe.

3. The in-situ leaching uranium directional drilling wellbore structure according to claim 2, wherein the straight section casing is made of polyvinyl chloride or hard polyvinyl chloride material, the build-up section casing is made of glass fiber reinforced plastic material, the anti-extraction pipe is made of glass fiber reinforced plastic material, and the packer is made of stainless steel material.

4. A directional drilling wellbore structure for in-situ leaching of uranium according to claim 1, characterised in that, The in-situ leaching uranium directional drilling wellbore structure further comprises: an adapter casing, the first end of the adapter casing being threadedly connected with the straight section casing, and the second end of the adapter casing being threadedly connected with the build-up section casing; wherein the first end of the adapter casing is provided with a first internal thread, and the second end of the adapter casing is provided with a first external thread.

5. An in-situ leaching method for uranium mining, characterised in that, The method is applied to the in-situ leaching uranium directional drilling wellbore structure according to claim 4, and the method comprises: drilling a straight section, after the straight section casing is lowered into the straight section, injecting mud in reverse, and after the mud is solidified, cutting a window in the uranium ore section to form a straight section annulus space; drilling the straight section and the build-up section of the horizontal well, and sequentially lowering the anti-extraction pipe, the build-up section casing, the adapter casing and the straight section casing, and cementing the well with mud; drilling the horizontal section of the horizontal well, and adjusting the trajectory in real time to make the tail end of the horizontal section butt against the straight section annulus space; lowering the horizontal section screen pipe into the horizontal section, and fixing the horizontal section screen pipe in the anti-extraction pipe; lowering a liquid injection pipe from the wellhead of the vertical section, sealing the wellhead of the vertical section; injecting leaching solution from the liquid injection pipe, the leaching solution permeating into the uranium ore bed through the horizontal section screen pipe, and after the leaching solution dissolves the uranium minerals, lifting the leaching solution to the ground surface.

6. The in-situ leaching uranium mining method according to claim 5, wherein, the vertical section and the build-up section of the horizontal well are drilled, and the anti-dropping pipe, the build-up section casing, the adapter casing and the vertical section casing are sequentially lowered, and the well is cemented with mud, including the steps of: the vertical section and the build-up section are drilled open hole; well trajectory logging and well diameter logging are performed on the horizontal well; after the horizontal well logging is qualified, the horizontal well is treated by punching; the anti-dropping pipe, the build-up section casing, the adapter casing and the vertical section casing are sequentially lowered, and then the well is cemented with mud.

7. The in-situ leaching uranium mining method according to claim 5, wherein, the horizontal section of the horizontal well is drilled, and the trajectory is adjusted in real time, so that the tail end of the horizontal section is docked with the annular space of the vertical section, including the steps of: the horizontal section is drilled using directional drilling technology, and uranium ore bed logging and drilling guidance are performed during drilling; according to the actual distribution of the uranium ore bed, the well trajectory of the horizontal section is adjusted so that the tail end of the horizontal section is docked with the annular space of the vertical section; the horizontal section screen pipe is installed on a drilling tool, and the horizontal section screen pipe is slowly fed into the horizontal section through the drilling tool; during the broadcasting of the horizontal section screen pipe, high-pressure punching is performed, and liquid is pumped out of the process vertical well to dredge the borehole of the horizontal section; after the horizontal section screen pipe reaches the designed position in the horizontal section, the horizontal section screen pipe is fixed by setting the packer in the anti-dropping pipe.

8. The in-situ leaching uranium mining method according to claim 5, wherein, the anti-dropping pipe is lowered from the wellhead of the vertical section, and the wellhead of the vertical section is sealed, including the steps of: before liquid injection, the downhole part of the process vertical well is sealed by a sealing device, so that the pressure resistance of the part below the sealed section exceeds the designed liquid injection pressure; the liquid injection pipe is lowered from the wellhead of the horizontal well, a sealing device is installed at the wellhead of the horizontal well to seal the annular gap between the liquid injection pipe and the vertical section casing, and a sealing test is performed.

9. A method of in-situ leaching of uranium as claimed in any one of claims 5 to 8 wherein, The method further includes: injecting chemical washing fluid into the wellbore, sealing and soaking for 24-72 hours to remove chemical blockages near the horizontal section screen pipe; after soaking, turbid liquid containing dissolved chemical blockages is pumped out of the process vertical well; degradable washing fluid is injected into the wellbore under high pressure, and liquid is pumped out through the process vertical well; suspended solids in the degradable washing fluid are filtered, and the washing is continuously circulated for 24-72 hours to remove the accumulated mud and sand blockages in the horizontal section screen pipe and the wellbore.

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