In-situ leaching uranium mining directional drilling shaft structure and method

Abstract

The invention provides an in-situ leaching uranium mining directional drilling well shaft structure and method and belongs to the technical field of in-situ leaching uranium mining well completion, the in-situ leaching uranium mining directional drilling well shaft structure comprises a vertical well section sleeve, a deflecting section sleeve, a horizontal section screen pipe and an anti-disengaging pipe, a shaft is of a split type composite structure, the sleeves made of different materials are reasonably compounded so as to improve the overall strength of the sleeves in the shaft, the sleeves are prevented from being damaged, and the service life of the shaft is prolonged. The supporting strength and the structural stability of the shaft are improved, and meanwhile the corrosion damage possibility of the shaft is reduced; the horizontal section screen pipe penetrates through the anti-disengaging pipe and then is embedded into the deflecting section sleeve, the horizontal section screen pipe and the deflecting section sleeve are connected and fixed through the anti-disengaging pipe, displacement of the horizontal section screen pipe is prevented, the connecting end of the horizontal section screen pipe is of a double-layer structure, and the horizontal section screen pipe inside is supported and protected through the anti-disengaging pipe. The connecting reliability of the horizontal section screen pipe and the deflecting section sleeve is improved.

Description

Technical Field

[0001] The present application belongs to the technical field of in-situ uranium leaching well drilling, and specifically relates to a wellbore structure and method for in-situ uranium leaching directional drilling. Background Art

[0002] In-situ leaching is a common uranium mining method. It involves injecting a leaching agent, which chemically reacts with the uranium minerals in the ore layer, dissolving the uranium and then pumping it to the surface. Traditional directional drilling wellbores are susceptible to aging and damage during in-situ leaching, which can destroy the original components of the leachate, shortening the mine life and increasing the cost of subsequent hydrometallurgical operations. Summary of the Invention

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

[0004] To this end, a first aspect of the present invention provides a wellbore structure for directional drilling of uranium in situ leaching.

[0005] A second aspect of the present invention provides a method for in-situ leaching of uranium.

[0006] In view of this, according to a first aspect of an embodiment of the present application, a wellbore structure for in-situ uranium leaching directional drilling is proposed, comprising:

[0007] Vertical well section casing, the vertical well section casing is arranged in the vertical well section along the length direction of the vertical well section;

[0008] The casing of the deflection section is arranged in the deflection section, and the first end of the casing of the deflection section is connected to the casing of the vertical well section;

[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 the second end of the casing of the beveling section;

[0010] The anti-drop-off pipe is installed on the outside of the horizontal section screen pipe and is connected to the second end of the deflection section casing to limit the horizontal section screen pipe through the anti-drop-off pipe.

[0011] In a feasible embodiment, the in-situ uranium directional drilling wellbore structure further includes:

[0012] The packer is sleeved on the outside of the horizontal section screen pipe. The packer is located between the horizontal section screen pipe and the anti-dropout pipe. The packer fills the annular gap between the horizontal section screen pipe and the anti-dropout pipe and fixes the horizontal section screen pipe in the anti-dropout pipe.

[0013] In a feasible implementation, the casing of the vertical well section is made of polyvinyl chloride or rigid polyvinyl chloride; the casing of the deflection section is made of fiberglass; the anti-slip pipe is made of fiberglass; and the packer is made of stainless steel.

[0014] In a feasible embodiment, the in-situ uranium directional drilling wellbore structure further includes:

[0015] A transition casing, wherein a first end of the transition casing is threadedly connected to the casing of the vertical well section, and a second end of the transition casing is threadedly connected to the casing of the deflection section;

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

[0017] In a feasible embodiment, the anti-drop tube includes:

[0018] The main body is a hollow cavity with openings at both ends;

[0019] A first thread is provided on the inner wall of the first end of the main body, and the main body is threadedly connected to the casing of the beveling section through the first thread;

[0020] A stepped groove is provided on the inner wall of the main body along the circumference of the main body, and the stepped groove cooperates with the outer wall of the packer;

[0021] The anti-slipping mouth is arranged at the second end of the main body, and the horizontal section screen pipe is interference fit with the anti-slipping mouth;

[0022] The guide port is located between the anti-slip port and the stepped groove, the guide port is connected to the anti-slip port, and the inner diameter of the guide port gradually increases from an end close to the anti-slip port to an end away from the anti-slip port.

[0023] According to a second aspect of an embodiment of the present application, a method for in-situ uranium leaching is proposed, which is applied to a directional drilling wellbore structure for in-situ uranium leaching as in any of the above technical solutions, comprising:

[0024] Drilling a vertical well: After running the vertical well casing into the vertical well, reversely inject mud. After the mud solidifies, cut a window in the uranium ore layer to form the vertical well annulus space.

[0025] Drill the vertical section and the deflection section of the horizontal well, and run the anti-dropout pipe, the deflection section casing, the transition casing and the vertical section casing in sequence, and cement the well with mud;

[0026] Drill the horizontal section of the horizontal well and adjust the trajectory in real time so that the tail end of the horizontal section aligns with the annulus of the vertical well;

[0027] Put the horizontal section screen pipe into the horizontal section and fix the horizontal section screen pipe in the anti-drop pipe;

[0028] Run the injection pipe from the wellhead of the vertical well section to seal the wellhead of the vertical well section;

[0029] The leaching liquid is injected from the injection pipe, and the leaching liquid penetrates into the uranium ore layer through the horizontal section screen pipe. After the leaching liquid dissolves the uranium minerals, the leaching liquid is lifted to the ground.

[0030] In a feasible embodiment, drilling a vertical well section and a deflection section of a horizontal well, and sequentially running an anti-dropout pipe, a deflection section casing, a transition casing, and a vertical well section casing, and cementing the well with mud, includes the following steps:

[0031] Open hole construction of vertical well section and deflection section;

[0032] Conduct well trajectory logging and caliper logging for horizontal wells;

[0033] After the horizontal well logging is qualified, the horizontal well is punched;

[0034] The anti-dropout pipe, deflection section casing, transition casing and vertical well section casing are sequentially run in, and then the well is cemented with mud.

[0035] In a feasible embodiment, the horizontal section of a horizontal well is drilled and the trajectory is adjusted in real time so that the tail end of the horizontal section is connected to the annulus space of the vertical well, including the following steps:

[0036] Directional drilling technology is used to construct the horizontal section, and uranium ore layer logging and drilling guidance are carried out during the drilling process;

[0037] According to the actual distribution of the uranium ore layer, the wellbore trajectory of the horizontal section is adjusted so that the tail end of the horizontal section is connected with the annulus space of the vertical well;

[0038] Install the horizontal section screen onto the drilling tool and slowly push the horizontal section screen into the horizontal section through the drilling tool;

[0039] During the laying of the horizontal screen, high-pressure punching is used and fluid is pumped from the process vertical well to dredge the wellbore in the horizontal section.

[0040] After the horizontal section screen pipe reaches the designed position in the horizontal section, the horizontal section screen pipe is sealed and fixed in the anti-dropout pipe through the packer.

[0041] In a feasible embodiment, a liquid injection pipe is lowered from the wellhead of the vertical well section to seal the wellhead of the vertical well section, including the following steps:

[0042] Before injection, the downhole part of the process vertical well is sealed by the isolation device so that the pressure resistance of the part below the sealing section exceeds the designed injection pressure;

[0043] An injection pipe is lowered into the wellhead of the horizontal well, and a sealing device is installed at the wellhead of the horizontal well to seal the annular gap between the injection pipe and the casing of the vertical well section, and a sealing test is performed.

[0044] In a feasible embodiment, the method further includes:

[0045] Inject chemical flushing fluid into the wellbore, seal the well and soak for 24 to 72 hours to remove chemical blockages near the horizontal screen pipe;

[0046] After the soaking is completed, the turbid liquid containing dissolved chemical blockages is extracted through the process vertical well;

[0047] Inject degradable well-washing fluid into the wellbore at high pressure and pump the fluid through the process vertical well;

[0048] Filter the suspended matter in the degradable well washing fluid, continuously circulate the well washing for 24 hours to 72 hours, and remove the mud and sand blockages accumulated in the horizontal section screen pipe and the well body.

[0049] Compared with the prior art, the present invention provides a wellbore structure and method for directional drilling of in-situ uranium leaching, which has the following beneficial effects:

[0050] The in-situ uranium directional drilling wellbore structure provided in the embodiment of the present application includes a vertical well casing, an inclined section casing, a horizontal section screen pipe and an anti-slip pipe. The wellbore adopts a split composite structure, and casings of different materials are reasonably composited to improve the overall strength of each section of the casing in the wellbore, avoid casing damage, improve the supporting strength and structural stability of the wellbore, and reduce the possibility of corrosion damage to the wellbore; the horizontal section screen pipe passes through the anti-slip pipe and is embedded in the inclined section casing. The horizontal section screen pipe and the inclined section casing are connected and fixed by the anti-slip pipe to prevent the horizontal section screen pipe from displacement, and the horizontal section screen pipe connection end is made into a double-layer structure, and the anti-slip pipe is used to support and protect the internal horizontal section screen pipe to improve the connection reliability between the horizontal section screen pipe and the inclined section casing. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiment below. The accompanying drawings are for illustration purposes only and are not to be considered as limiting the present application. The same reference symbols are used throughout the drawings to represent the same components. In the drawings:

[0052] Figure 1 A schematic structural diagram of a directional drilling wellbore structure for in-situ uranium leaching according to an embodiment of the present application;

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

[0054] Figure 3 A schematic structural diagram of an anti-slip pipe of a wellbore structure for in-situ uranium directional drilling provided in accordance with an embodiment of the present application;

[0055] Figure 4 A schematic structural diagram of a wellbore structure during liquid injection for directional drilling of in-situ uranium leaching according to an embodiment of the present application;

[0056] Figure 5A schematic structural diagram of a wellbore structure during well washing for in-situ uranium directional drilling provided by an embodiment of the present application;

[0057] Figure 6 A schematic flow chart of the steps of an in-situ leaching method for uranium mining according to an embodiment of the present application;

[0058] in, Figures 1 to 5 The corresponding relationship between the reference numerals and component names is as follows:

[0059] 1. Vertical well casing; 2. Casing in the deflection section; 3. Horizontal section screen; 4. Anti-dropout pipe; 5. Packer; 6. Adapter casing; 7. First internal thread; 8. First external thread;

[0060] 22. Vertical well section; 23. Deflection section; 24. Horizontal section; 25. Process vertical well casing; 26. Vertical well annulus; 27. Injection pipe; 28. Packer; 29. ​​Sealing device; 30. Lifting device; 31. Uranium ore layer; 32. Ore layer annulus;

[0061] 41. Main body; 42. First thread; 43. Step groove; 44. Anti-slip opening; 45. Guide opening. DETAILED DESCRIPTION

[0062] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0063] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. Throughout the description of this application, "plurality" means two or more, unless otherwise specifically defined.

[0064] In this application, unless otherwise specified or limited, the terms "mounted," "connected," "connect," "fixed," etc. should be understood broadly. For example, they can refer to fixed connection, detachable connection, or integral connection; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; or internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on 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 herein are only used to illustrate and explain the present application and are not used to limit the present application.

[0066] like Figure 1 As shown, according to the first aspect of the embodiment of the present application, a directional drilling wellbore structure for in-situ uranium leaching is proposed, including: a vertical well section casing 1, an inclined section casing 2, a horizontal section screen 3 and an anti-slip pipe 4, the vertical well section casing 1 is arranged in the vertical well section 22 along the length direction of the vertical well section 22; the inclined section casing 2 is arranged in the inclined section 23, and the first end of the inclined section casing 2 is connected to the vertical well section casing 1; the horizontal section screen 3 is arranged in the horizontal section 24 along the length direction of the horizontal section 24, the horizontal section screen 3 and the horizontal section 24 form an ore layer annulus space 32, and the first end of the horizontal section screen 3 is embedded in the second end of the inclined section casing 2; the anti-slip pipe 4 is installed on the outside of the horizontal section screen 3, and the anti-slip pipe 4 is connected to the second end of the inclined section casing 2 to limit the horizontal section screen 3 by the anti-slip pipe 4.

[0067] The in-situ uranium directional drilling wellbore structure provided in the embodiment of the present application includes a vertical well section casing 1, an inclined section casing 2, a horizontal section screen pipe 3 and an anti-slip pipe 4. The wellbore adopts a split composite structure, and casings of different materials are reasonably composited to improve the overall strength of each section of the casing in the wellbore, avoid casing damage, improve the supporting strength and structural stability of the wellbore, and reduce the possibility of corrosion damage to the wellbore; the horizontal section screen pipe 3 passes through the anti-slip pipe 4 and is embedded in the inclined section casing 2. The horizontal section screen pipe 3 and the inclined section casing 2 are connected and fixed by the anti-slip pipe 4 to prevent the horizontal section 24 and the horizontal section screen pipe 3 from being displaced, and the connecting end of the horizontal section screen pipe 3 is a double-layer structure, and the anti-slip 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 inclined section casing 2.

[0068] Furthermore, the length of the vertical well section casing 1 is determined according to the depth of the vertical well section 22 of the horizontal well, and the vertical well section casing 1 extends vertically from the wellhead of the vertical well section 22 to the starting point of the inclined section 23; the length of the horizontal section screen 3 covers the range of the target uranium ore layer 31; the shape of the inclined section casing 2 matches the shape of the inclined section 23 of the horizontal well, and the curvature of the bend of the inclined section casing 2 is consistent with the curvature of the trajectory of the inclined section 23, ensuring that the inclined section casing 2 can smoothly enter the horizontal section 24 from the inclined section 23.

[0069] like Figure 1 As shown, in a feasible embodiment, the in-situ uranium directional drilling wellbore structure also includes: a packer 5, which is sleeved on the outside of the horizontal section screen pipe 3, and the packer 5 is located between the horizontal section screen pipe 3 and the anti-detachment pipe 4. The packer 5 fills the annular gap between the horizontal section screen pipe 3 and the anti-detachment pipe 4, and fixes the horizontal section screen pipe 3 in the anti-detachment pipe 4.

[0070] In this technical solution, the packer 5 is mounted on the horizontal section screen 3, and the packer 5 is embedded in the anti-slip tube 4. The packer 5 seals the annular gap between the horizontal section screen 3 and the anti-slip tube 4 to prevent the leaching liquid from directly entering the annular gap, thereby ensuring the directional penetration of the leaching liquid from the horizontal section screen 3 to the uranium ore layer 31; at the same time, the horizontal section screen 3 is fixedly connected to the anti-slip tube 4 through the packer 5, supporting and fixing the horizontal section screen 3 to ensure the connection stability between the horizontal section screen 3 and the inclined section casing 2.

[0071] In some examples, the horizontal section screen 3 is anchored by hydraulic or mechanical setting to seal the annular gap between the deflection section casing 2 and the horizontal section screen 3, thereby resisting the flow impact of the immersion fluid.

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

[0073] In a feasible embodiment, the vertical well section casing 1 is made of polyvinyl chloride or rigid polyvinyl chloride; the deflection section casing 2 is made of fiberglass; the anti-slip pipe 4 is made of fiberglass; and the packer 5 is made of stainless steel.

[0074] In this technical solution, the vertical well section casing 1 is made of polyvinyl chloride or rigid polyvinyl chloride, which is low in cost and resistant to chemical corrosion; the inclined section casing 2 and the anti-slip pipe 4 are made of high-strength fiberglass material, so that the inclined section casing 2 and the anti-slip pipe 4 have a high strength ratio and a large bending strength. The vertical well section casing 1 and the inclined section casing 2 are made of different materials, which improves the supporting capacity of the wellbore while ensuring the corrosion resistance of the wellbore; the packer 5 is made of stainless steel, which is resistant to high-pressure corrosion, reduces the risk of brittle fracture at the anchoring point of the horizontal section screen 3 on the anti-slip pipe 4, and ensures the overall pressure resistance of the wellbore; suitable anti-corrosion materials are selected at various positions of the wellbore to improve the corrosion resistance of the wellbore on the basis of ensuring the strength and supporting capacity of the wellbore, which helps to extend the service life of the wellbore and reduce maintenance costs.

[0075] In some examples, the vertical well casing 1 is made of rigid polyvinyl chloride, has an outer diameter of 152 mm to 190 mm, and a wall thickness of 8 mm to 16 mm. Preferably, the outer diameter of the vertical well casing 1 is 190 mm, and the wall thickness of the vertical well casing 1 is 16 mm.

[0076] The inclined section casing 2 is made of glass fiber reinforced plastic, with an outer diameter of 152mm to 190mm and a wall thickness of 8mm to 16mm. As a preferred embodiment, the outer diameter of the inclined section casing 2 is 190mm and the wall thickness of the vertical well casing 1 is 16mm.

[0077] Furthermore, the horizontal section screen pipe 3 is made of reinforced fiberglass, the outer diameter of the horizontal section screen pipe 3 matches the inner diameter of the beveling section casing 2, and the wall thickness of the horizontal section screen pipe 3 is 15mm to 20mm; the surface of the horizontal section screen pipe 3 is evenly provided with parallel filter slots, the slot width of the filter slot is 0.4mm to 0.6mm, the slot length is 50mm, and the slot spacing is 10mm.

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

[0079] In this technical solution, the straight well section casing 1 and the inclined section casing 2 are both threadedly connected to the adapter casing 6, and the adapter casing 6 connects the straight well section casing 1 and the inclined section casing 2 to avoid interface leakage caused by the difference in expansion coefficients between the straight well section casing 1 and the inclined section casing 2, and to achieve effective connection between the straight well section casing 1 and the inclined section casing 2 of different materials.

[0080] like Figure 3As shown, in a feasible embodiment, the anti-slip pipe 4 includes: a main body 41, a first thread 42, a stepped groove 43, an anti-slip opening 44 and a guide opening 45; the main body 41 is a hollow cavity with openings at both ends; the first thread 42 is arranged 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 casing 2 through the first thread 42; the stepped groove 43 is arranged on the inner wall of the main body 41 along the circumference of the main body 41, and the stepped groove 43 cooperates with the outer wall of the packer 5; the anti-slip opening 44 is arranged at the second end of the main body 41, and the horizontal section screen 3 is interference fit with the anti-slip opening 44; the guide opening 45 is located between the anti-slip opening 44 and the stepped groove 43, and the guide opening 45 is connected to the anti-slip opening 44, and the inner diameter of the guide opening 45 gradually increases from the end close to the anti-slip opening 44 to the end away from the anti-slip opening 44.

[0081] In this technical solution, the anti-slip pipe 4 forms a double anti-slip structure by setting a stepped groove 43, an anti-slip opening 44 and a guide opening 45: the anti-slip pipe 4 cooperates with the external thread of the packer 5 through the stepped groove 43, so that the packer 5 and the anti-slip pipe 4 are self-locked, and the pull-out resistance of the packer 5 is improved to prevent the packer 5 from being displaced in the axial direction of the anti-slip pipe 4, thereby ensuring the relative position stability between the horizontal section screen pipe 3 and the anti-slip pipe 4, and ensuring the stability of the fixation of the horizontal section screen pipe 3; the horizontal section screen pipe 3 and the anti-slip opening 44 have an interference fit to prevent the axial sliding of the horizontal section screen pipe 3; the horizontal section screen pipe 3 is installed from the end where the anti-slip pipe 4 is connected to the inclined section casing 2, and the guide opening 45 plays a guiding role when the horizontal section screen pipe 3 is installed, ensuring that the horizontal section screen pipe 3 smoothly enters the anti-slip opening 44, avoids the horizontal section screen pipe 3 from getting stuck when it is sent in, and ensures the construction efficiency of the wellbore.

[0082] like Figure 1 As shown, in a feasible embodiment, the in-situ uranium directional drilling wellbore structure also includes: a process vertical well, the process vertical well is parallel to the vertical well section 22 of the horizontal well, a vertical well annulus space 26 is provided on the process vertical well, the horizontal section 24 is connected to the vertical well annulus space 26, and the horizontal section screen pipe 3 extends 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 window in the uranium ore layer 31 to form a vertical well annulus 26. This facilitates the precise placement and docking of the horizontal well's horizontal section 24, 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 26 provides a buffer zone, reducing stress concentration in the deflection section 23 and horizontal section 24, and helping to prevent the horizontal section screen 3 from falling off. A process vertical well casing 25 is installed within the process vertical well, serving as a fluid circulation node during subsequent fluid injection. During horizontal well construction, the process vertical well is used to extract sediment from the wellbore collapse, ensuring the smooth placement of the horizontal section 24 and horizontal section screen 3. During well flushing and maintenance, the process vertical well serves as a pumping channel to extract dissolved blockages within the uranium ore layer 31.

[0084] like Figure 4 As shown, in a feasible embodiment, the wellbore structure for in-situ uranium leaching directional drilling also includes: an injection pipe 27 and a sealing device 28; the injection pipe 27 is arranged in the vertical well section 22, and the injection pipe 27 and the wellhead of the vertical well section 22 are sealed by a sealing device 29; the sealing device 28 is provided in the process vertical well to seal the process vertical well during injection.

[0085] In this technical solution, during the injection process, an injection pipe 27 is lowered and a sealing device 29 is used to seal the horizontal well, and a sealing device 28 is used to block the process vertical well to form a sealing section in the process vertical well. This prevents the leaching liquid from leaking from the process vertical well or flowing upward into the vertical well annulus space 26 during the injection process, thereby ensuring that the leaching liquid flows in a directional manner toward the uranium ore layer 31. At the same time, it prevents pressure leakage in the well, ensures that the leaching liquid uniformly penetrates the uranium ore layer 31, and ensures the dissolution efficiency of the uranium mineral. By sealing the wellbore, the leaching liquid is prevented from flowing back from the process vertical well or leaking to non-target areas, thereby avoiding damage to the leaching liquid components and reducing the leaching effect, improving the leaching efficiency, and extending the service life of the wellbore.

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

[0087] In this technical solution, during the well washing process, a lifting device 30 is set in the process vertical well to carry out the well washing fluid pumping operation; during the well washing, high-pressure well washing fluid is injected into the horizontal well, and at the same time, the process vertical well is pumped out, and the lifting device 30 extends into the vertical well annulus space 26 to lift the blockage to the surface to prevent the blockage from accumulating in the horizontal section 24 and the vertical well annulus space 26.

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

[0089] Step 100: Drilling a vertical well. After running a vertical well casing into the vertical well, reversely injecting mud. After the mud solidifies, a window is cut in the uranium ore layer 31 to form a vertical well annulus space 26.

[0090] Step 200: Drilling the vertical well section 22 and the deflection section 23 of the horizontal well, and sequentially running the anti-dropout pipe 4, the deflection section casing 2, the transition casing 6, and the vertical 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 so that the tail end of the horizontal section 24 is aligned with the annulus 26 of the vertical well;

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

[0093] Step 500: inserting the injection pipe 27 from the wellhead of the vertical well section 22 to seal the wellhead of the vertical well section 22;

[0094] Step 600: Inject the leaching liquid from the injection pipe 27, and the leaching liquid penetrates into the uranium ore layer 31 through the horizontal section screen pipe 3. After the leaching liquid dissolves the uranium ore, the leaching liquid is lifted to the ground from the boreholes in the well site except the horizontal wells and process vertical wells.

[0095] According to the in-situ leaching uranium mining method provided in the embodiment of the present application, a supporting process vertical well is first constructed to facilitate cutting a vertical well annulus space 26 in the uranium ore layer 31, and then the vertical well section 22 and the inclined section 23 of the horizontal well are constructed, and the anti-slip pipe 4, the inclined section casing 2, the transition casing 6 and the vertical well section casing 1 are sequentially introduced; the horizontal section 24 is constructed to connect the horizontal section 24 with the vertical well annulus space 26 to form a directional leaching channel; then the horizontal section screen pipe 3 is introduced and connected to the horizontal section screen pipe 3 with the anti-slip pipe 4 to accurately inject the leaching liquid into the uranium ore layer 31 through the horizontal section screen pipe 3, and then the leaching liquid is lifted to the ground from other boreholes in the well site.

[0096] Furthermore, during the later stage of wellbore cleaning and maintenance, the supporting process vertical well creates negative pressure by pumping liquid from the lifting pipe to improve the well washing efficiency, and lifts the well washing blockage to the ground for collection and treatment, ensuring the 24 injection and leaching effect of the horizontal section.

[0097] In a feasible embodiment, the vertical well section 22 and the inclined section 23 of the horizontal well are drilled, and the anti-dropout pipe 4, the inclined section casing 2, the transition casing 6 and the vertical well section casing 1 are sequentially lowered, and the well is cemented with mud, including the steps of: constructing the vertical well section 22 and the inclined section 23 in an open hole; performing well trajectory logging and well diameter logging on the horizontal well; after the horizontal well logging is qualified, punching the horizontal well; lowering the anti-dropout pipe 4, the inclined section casing 2, the transition casing 6 and the vertical well section casing 1 sequentially, and then cementing the well with mud.

[0098] In this technical solution, open hole logging is combined with punching and casing cementing to ensure well wall stability; wellbore logging is used to identify collapsed sections to facilitate subsequent targeted cementing and sealing, saving on sealing mud.

[0099] In a feasible embodiment, 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 docked with the annulus space 26 of the vertical well, including the following steps: using directional drilling technology to construct the horizontal section 24, and performing well logging and drilling guidance of the uranium ore layer 31 during the drilling process; adjusting the wellbore trajectory of the horizontal section 24 according to the actual distribution of the uranium ore layer 31 so that the tail end of the horizontal section 24 is docked with the annulus space 26 of the vertical well; installing the horizontal section screen pipe 3 on the drilling tool, and slowly sending the horizontal section screen pipe 3 into the horizontal section 24 through the drilling tool; during the delivery of the horizontal section screen pipe 3, high-pressure punching is performed and liquid is pumped from the process vertical well to dredge the wellbore of the horizontal section 24; after the horizontal section screen pipe 3 reaches the designed position in the horizontal section 24, the horizontal section screen pipe 3 is sealed and fixed in the anti-slip pipe 4 by the packer 5.

[0100] In this technical solution, the trajectory of the horizontal section 24 is corrected in real time through well logging to improve the drilling rate of the uranium ore layer 31 in the horizontal section 24; after high-pressure punching, negative pressure sand is pumped down the pipe, and then the horizontal section screen pipe 3 is sent into the horizontal section 24 by using a drilling tool and fixed in the anti-slip pipe 4 by a packer 5 to avoid axial displacement of the horizontal section screen pipe 3, thereby avoiding injection short-circuiting caused by the horizontal section screen pipe 3 falling off due to vibration.

[0101] Furthermore, during the laying process of the horizontal section screen pipe 3, high-pressure punching is performed to dredge the wellbore of the horizontal section 24, and a screw pump is used in the supporting process vertical well to continuously pump liquid, so that a negative pressure is formed between the process vertical well and the horizontal section 24, and mud and sand that has collapsed or settled on the well wall is continuously pumped out. By suctioning and discharging slag under negative pressure when the horizontal section screen pipe 3 is lowered, it is ensured that the laying of the horizontal section screen pipe 3 is smooth and unblocked, so that the horizontal section screen pipe 3 can be quickly installed in place.

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

[0103] In this technical solution, a sealing test is performed before injection to ensure the reliability of the seal before injection. Through downhole isolation and wellhead sealing, the isolation device 28 blocks the process vertical well to form a sealing section in the process vertical well, preventing the leachate from leaking from the process vertical well or rising into the vertical well annulus space 26 during the injection process, ensuring that the leachate flows in a directional manner toward the uranium ore layer 31, and at the same time preventing pressure leakage in the well, improving the utilization rate of the leachate, preventing leakage of high-pressure leachate during injection, ensuring that the leachate evenly penetrates the uranium ore layer 31, and ensuring the dissolution efficiency of the uranium mineral.

[0104] In a feasible embodiment, the method also includes: injecting chemical well washing fluid into the wellbore, sealing the well and soaking it for 24 hours to 72 hours to remove chemical blockages near the horizontal section screen pipe 3; after the soaking is completed, extracting the turbid liquid containing dissolved chemical blockages through the process vertical well; injecting degradable well washing fluid into the wellbore at high pressure and pumping the fluid through the process vertical well; filtering suspended matter in the degradable well washing fluid, and continuously circulating the well washing for 24 hours to 72 hours to remove mud and sand blockages accumulated in the horizontal section screen pipe 3 and the well body.

[0105] In this technical solution, a weakly acidic chemical well-washing fluid is injected to dissolve calcium and magnesium scale, remove chemical blockages near the horizontal section screen pipe 3, and restore permeability. Then, a degradable well-washing fluid is injected for mechanical and physical cleaning, removing mud and sand accumulated in the horizontal section screen pipe 3 and the wellbore. Active well washing reduces wellbore corrosion and extends the operating time of the uranium mine.

[0106] The in-situ uranium leaching method provided in the embodiment of the present application is applied to the in-situ uranium leaching directional drilling wellbore structure as any of the above-mentioned technical solutions. Therefore, the in-situ uranium leaching method has all the beneficial effects of the in-situ uranium leaching directional drilling wellbore structure of the above-mentioned technical solutions, which will not be described in detail here.

[0107] Example:

[0108] Take the in-situ leaching of uranium in a uranium mine as an example:

[0109] Well depth structure: vertical section 400m, inclined section 200m long, bending radius 130m, horizontal section 100m long.

[0110] Material parameters:

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

[0112] The casing of the inclined section is made of fiberglass with an outer diameter of 190mm, a wall thickness of 14mm and an anti-external extrusion strength of ≥20MPa.

[0113] The horizontal section screen pipe is a fiberglass screen pipe with an outer diameter of 152, a wall thickness of 20mm, and an anti-external collapse strength ≥16MPa; it is slotted, with a single slot width of 0.6mm, a slot length of 100mm, and 40 slots / meter.

[0114] The wellbore structure has been operating continuously for one year in a leachate with a pH of 5. All casings have no corrosion or perforation, and the horizontal section screen has not shifted or fallen off.

[0115] It is easy for those skilled in the art to understand that the above embodiments can be freely combined and superimposed without conflict.

[0116] The above are merely preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application. The above are merely preferred embodiments of the present application. It should be noted that those skilled in the art may make various improvements and variations without departing from the technical principles of the present application, and such improvements and variations shall also be considered within the scope of protection of the present application.

Claims

1. A directional drilling wellbore structure for in-situ uranium leaching, characterized in that: The in-situ uranium directional drilling wellbore structure comprises: A vertical well section casing, wherein the vertical well section casing is arranged in the vertical well section along the length direction of the vertical well section; A deflection section casing, wherein the deflection section casing is disposed in the deflection section, and a first end of the deflection section casing is connected to the vertical well section casing; a horizontal section screen pipe, wherein the horizontal section screen pipe is arranged in the horizontal section along the length direction of the horizontal section, and the first end of the horizontal section screen pipe is embedded in the second end of the deflection section casing; An anti-slip pipe is installed on the outside of the horizontal section screen pipe and is connected to the second end of the deflection section casing to limit the horizontal section screen pipe through the anti-slip pipe.

2. The directional drilling wellbore structure for in-situ uranium leaching according to claim 1, characterized in that: The in-situ uranium directional drilling wellbore structure further comprises: A packer is sleeved on the outside of the horizontal section screen pipe, the packer is located between the horizontal section screen pipe and the anti-detachment pipe, the packer fills the annular gap between the horizontal section screen pipe and the anti-detachment pipe, and fixes the horizontal section screen pipe in the anti-detachment pipe.

3. The directional drilling wellbore structure for in-situ uranium leaching according to claim 2, characterized in that: The casing of the vertical well section is made of polyvinyl chloride or rigid polyvinyl chloride; the casing of the deflection section is made of glass fiber reinforced plastic; the anti-slip pipe is made of glass fiber reinforced plastic; and the packer is made of stainless steel.

4. The directional drilling wellbore structure for in-situ uranium leaching according to claim 1, characterized in that: The in-situ uranium directional drilling wellbore structure further comprises: A transition casing, wherein a first end of the transition casing is threadedly connected to the casing of the vertical well section, and a second end of the transition casing is threadedly connected to the casing of the deflection section; Wherein, the first end of the adapter sleeve is provided with a first internal thread, and the second end of the adapter sleeve is provided with a first external thread.

5. The directional drilling wellbore structure for in-situ uranium leaching according to claim 2, characterized in that: The anti-fall-off tube comprises: A main body, which is a hollow cavity with openings at both ends; a first thread, the first thread being provided on an inner wall of a first end of the main body, the main body being threadedly connected to the casing of the beveling section via the first thread; a stepped groove, the stepped groove being provided on the inner wall of the main body along the circumference of the main body, the stepped groove being matched with the outer wall of the packer; An anti-slip opening, the anti-slip opening being arranged at the second end of the main body, the horizontal section screen tube being interference fit with the anti-slip opening; The guide port is located between the anti-slip port and the stepped groove, the guide port is connected to the anti-slip port, and the inner diameter of the guide port gradually increases from an end close to the anti-slip port to an end away from the anti-slip port.

6. A method for in-situ leaching of uranium, characterized in that: Applied to a directional drilling wellbore structure for in-situ uranium leaching according to any one of claims 1 to 5, the method comprises: Drilling a vertical well, after running a vertical well casing in the vertical well, reversely injecting mud, after the mud solidifies, cutting a window in the uranium ore layer to form a vertical well annulus space; Drill the vertical section and the deflection section of the horizontal well, and run the anti-dropout pipe, the deflection section casing, the transition casing and the vertical section casing in sequence, and cement the well with mud; Drilling a horizontal section of the horizontal well and adjusting the trajectory in real time so that the tail end of the horizontal section docks with the annulus space of the vertical well; Inserting the horizontal section screen pipe into the horizontal section and fixing the horizontal section screen pipe in the anti-dropping pipe; Inserting a liquid injection pipe from the wellhead of the vertical well section to seal the wellhead of the vertical well section; Leaching liquid is injected from the injection pipe, and the leachating liquid penetrates into the uranium ore layer through the horizontal section screen pipe. After the leachating liquid dissolves the uranium ore, the leachating liquid is lifted to the ground.

7. The in-situ uranium leaching method according to claim 6, characterized in that: The method of drilling the vertical well section and the deflection section of the horizontal well, and sequentially running the anti-dropout pipe, the deflection section casing, the transition casing and the vertical well section casing, and cementing the well with mud includes the following steps: Open hole construction of the vertical well section and the deflection section; performing well trajectory logging and caliper logging on the horizontal well; After the horizontal well logging is qualified, the horizontal well is punched; The anti-dropout pipe, the deflection section casing, the transition casing and the vertical well section casing are sequentially run in, and then the well is cemented by mud.

8. The in-situ leaching method of uranium according to claim 6, characterized in that: The process of drilling the horizontal section of the horizontal well and adjusting the trajectory in real time so that the tail end of the horizontal section docks with the annulus of the vertical well comprises the following steps: The horizontal section is constructed using directional drilling technology, and uranium ore layer logging and drilling guidance are performed during the drilling process; According to the actual distribution of the uranium ore layer, the wellbore trajectory of the horizontal section is adjusted so that the tail end of the horizontal section is connected with the annulus space of the vertical well; Installing the horizontal section screen pipe on a drilling tool, and slowly feeding the horizontal section screen pipe into the horizontal section through the drilling tool; During the laying of the horizontal section screen, the wellbore of the horizontal section is dredged by high-pressure punching and pumping fluid from the process vertical well; After the horizontal section screen pipe reaches the designed position in the horizontal section, the horizontal section screen pipe is set and fixed in the anti-dropout pipe by a packer.

9. The in-situ leaching method of uranium according to claim 6, characterized in that: The step of lowering a liquid injection pipe from the wellhead of the vertical well section to seal the wellhead of the vertical well section comprises the following steps: Before injection, the downhole portion of the process vertical well is sealed by a sealing device so that the pressure resistance of the portion below the sealing section exceeds the designed injection pressure; The injection pipe is lowered into 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 injection pipe and the casing of the vertical well section, and a sealing test is performed.

10. A method for in-situ leaching of uranium according to any one of claims 6 to 9, characterized in that: The method further comprises: Inject chemical well-washing fluid into the wellbore, seal the well and soak for 24 hours to 72 hours to remove chemical blockages near the horizontal section screen pipe; After the soaking is completed, the turbid liquid containing dissolved chemical blockages is extracted through the process vertical well; injecting a degradable well-washing fluid into the wellbore at high pressure, and pumping the fluid through the process vertical well; The suspended matter in the degradable well-washing fluid is filtered and the well is continuously circulated for 24 to 72 hours to remove mud and sand blockages accumulated in the horizontal section screen and the wellbore.

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