Suspension support and pocket connection sealing device for built-in filter of cutting drill hole

Abstract

The invention belongs to the technical field of uranium mining and smelting, and particularly relates to a suspension support and pocket connection sealing device for a cutting and drilling built-in filter. According to the device provided by the invention, the three core functions of suspension supporting, annular sealing and sand setting bag expansion are creatively integrated into a whole. Through one-time tripping-in operation, reliable suspension fixing of the filter in a cut of a cutting cavity, reliable sealing of the device and a shaft annulus and effective utilization of the space of a shaft below can be achieved at the same time, and the underground pipe column structure and the operation process are greatly simplified. A sand setting pipe which is small in volume and connected with the lower section of the built-in filter is abandoned, and a casing shaft (pocket) below the notch of the cutting cavity is used as the sand setting pipe. Due to the fact that the diameter of the shaft is large, the volume capable of containing sand is obviously increased, and the stable operation time of drilling is effectively prolonged.

Description

Technical Field

[0001] This invention belongs to the field of uranium mining and metallurgy technology, specifically relating to a suspension support and pocket connection sealing device for a built-in filter in a cutting borehole. Background Technology

[0002] In in-situ leaching uranium mining, the built-in filter string plays a crucial role as a key structural component in cut-and-open-window boreholes. Currently, the built-in filter string commonly used in cut-and-open-window in-situ leaching boreholes in China has typical structural features, consisting of, from top to bottom, a guide head, packer, lead pipe, gravel feeding device, fixing device, filter tube, and settling pipe.

[0003] In terms of specific installation locations, the guide head, packer, guide pipe, and gravel dropping device are all installed in the wellbore above the borehole cutting section; the filter pipe is precisely installed in the cutting window section corresponding to the ore layer; the fixing device is arranged at the cut step at the upper end of the cutting section; the sand settling pipe is usually a pipe fitting with a bottom-sealed end, installed in the wellbore below the lower end of the cutting section.

[0004] However, the existing built-in filter string structure has a significant and unavoidable drawback: the sedimentation pipe connected to the lower section of the built-in filter has a small diameter and volume, resulting in a severely insufficient sediment-holding capacity of only 0.015m³-0.02m³. The direct consequence of this design is that the sedimentation pipe can only hold a very limited amount of sediment. In actual borehole operation, the sedimentation pipe is easily and rapidly filled with sand particles carried by the well fluid within approximately six months. Even more seriously, the sand particles may further accumulate upwards, even intruding into and clogging the filter pipe area. This series of problems not only severely shortens the stable water production cycle of the borehole, leading to a significant decrease in fluid production, but also significantly increases the frequency and cost of borehole maintenance, becoming one of the key factors restricting the long-term, efficient, and stable operation of in-situ leaching uranium boreholes. Summary of the Invention

[0005] To overcome the problems existing in related technologies, a suspension support and pocket connection sealing device for a built-in filter in a cutting borehole is provided, which is connected to the lower end of the filter tube. The device includes: a connector, a cylinder, a lever system, a push ring, a spring, and a spring seat.

[0006] The upper end of the connector is used to connect the filter tubing;

[0007] The upper end of the cylinder is connected to the lower end of the connector;

[0008] The lever system includes an upper lever and a lower lever that are hinged together by a pin, wherein the upper end of the upper lever is hinged to the upper part of the outer wall of the cylinder.

[0009] A push ring is sleeved on the outside of the cylinder and can slide along the cylinder axis. The outer wall of the push ring is hinged to the lower end of the lower lever.

[0010] A spring, sleeved on the outside of the cylinder and located below the push ring, is used to provide an elastic force that causes the push ring to slide upward along the cylinder;

[0011] A spring seat, connected to the lower end of the cylinder, is used to provide lower end support for the spring;

[0012] The outer wall of the spring seat is provided with an annular sealing groove, and a sealing component for sealing the annular space between the spring seat and the inner wall of the well barrel is installed in the groove.

[0013] When the device is lowered into the cutting chamber, the spring pushes the push ring upward, thereby driving the lever system to extend radially into a < shape, so as to suspend and support the filter string at the cut at the lower end of the cutting chamber; at the same time, the spring seat carries the sealing assembly and inserts it into the wellbore below the cut to achieve a seal.

[0014] In one possible implementation, the upper half of the device is located inside the cutting cavity, and the lower half is inserted into the wellbore below the cutting cavity.

[0015] In one possible implementation, multiple sets of first hinge seats are evenly distributed circumferentially on the upper part of the outer wall of the cylinder, and the upper end of the upper lever is hinged to the first hinge seats by a pin; multiple sets of second hinge seats are evenly distributed circumferentially on the outer wall of the push ring, and the lower end of the lower lever is hinged to the second hinge seats by a pin or bolt.

[0016] In one possible implementation, the outer wall of the cylinder is provided with an axial keyway, and the inner wall of the push ring is provided with a positioning pin that mates with the keyway, so that the push ring can slide along the axial direction of the cylinder but cannot rotate relative to it.

[0017] In one possible implementation, the spring is a pre-compression spring with a pre-compression range of 50-70 mm.

[0018] In one possible implementation, the spring seat is cylindrical, with its upper end connected to the lower end of the cylinder via an internal thread; the lower outer edge of the spring seat is provided with a guide chamfer.

[0019] In one possible implementation, the sealing assembly includes multiple sets of Y-shaped sealing rings installed in the annular sealing groove of the spring seat, with the V-shaped opening of the Y-shaped sealing rings facing upwards.

[0020] In one possible implementation, the Y-shaped sealing ring is made of nitrile rubber with a compression ratio maintained at 15%-20%.

[0021] In one possible implementation, once the device is installed, the wellbore space below the spring seat forms a sedimentation bag with an effective volume of not less than 0.3 cubic meters.

[0022] The beneficial effects of this disclosure are as follows: The device provided innovatively integrates three core functions—suspension support, annular sealing, and sand-filled bag expansion—into one unit. Through a single running operation, reliable suspension and fixation of the filter at the cutting cavity incision, reliable sealing between the device and the wellbore annulus, and effective utilization of the space below the wellbore can be achieved simultaneously, greatly simplifying the downhole tubing structure and operational procedures. It eliminates the need for the previously used, smaller-volume sand-filled pipe connected to the lower section of the built-in filter, instead utilizing the casing wellbore (bag) below the cutting cavity incision as the sand-filled pipe. Due to the larger wellbore diameter, the volume of sand that can be held is significantly increased, thereby effectively extending the stable operating time of the borehole.

[0023] The device employs a spring-driven lever deployment mechanism, enabling automatic triggering and locking of the suspension function. During lowering, the lever system remains contracted due to wellbore constraint; upon entering the cutting chamber, the well diameter increases, the spring automatically releases, pushing the push ring upwards and forcing the lever system to deploy radially, forming a stable and reliable mechanical support point. This firmly suspends the filter string in the predetermined position, avoiding the problems of unstable support or the need for complex surface operations that may exist with traditional methods. It eliminates the need for the small-volume sand-absorbing pipe previously connected to the lower section of the built-in filter, instead utilizing the casing wellbore pocket below the cutting chamber cut as the sand-absorbing pipe. Due to the larger wellbore diameter, the volume of sand that can be held is significantly increased, effectively extending the stable operating time of the borehole. Attached Figure Description

[0024] Figure 1 This is an assembly schematic diagram of a suspension support and pocket connection sealing device for a built-in filter in a cutting borehole, according to an exemplary embodiment.

[0025] Figure 2 This is an exploded view of a suspension support and pocket connection sealing device for a built-in filter in a cutting borehole, according to an exemplary embodiment.

[0026] Figure 3 This is a schematic diagram illustrating the usage state of a suspension support and pocket connection sealing device for a built-in filter in a cutting borehole, according to an exemplary embodiment. Detailed Implementation

[0027] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0028] A suspension support and pocket connection sealing device for an internal filter in a cutting drill hole is connected to the lower end of the filter tube. The device includes: a connector 1, a cylinder 2, a lever system 4, a push ring 5, a spring 6, and a spring seat 7. The upper end of the connector 1 is used to connect to the filter tube 11. The upper end of the cylinder 2 is connected to the lower end of the connector 1. The lever system 4 includes an upper lever 4-1 and a lower lever 4-3 hinged together by a pin. The upper end of the upper lever 4-1 is hinged to the upper part of the outer wall of the cylinder 2. The push ring 5 is sleeved on the filter tube. The outer wall of the push ring 5 is hinged to the lower end of the lower lever 4-3. The push ring 5 is sleeved on the outside of the cylinder 2 and located below the push ring 5, and is used to provide an elastic force to make the push ring 5 slide upward along the cylinder 2. The spring seat 7 is connected to the lower end of the cylinder 2 and is used to provide lower end support for the spring 6. The outer wall of the spring seat 7 is provided with an annular sealing groove, and a sealing component 8 for sealing the annular space between the spring seat 7 and the inner wall of the well barrel is installed in the groove.

[0029] When the device is lowered into the cutting chamber 13, the spring 6 pushes the push ring 5 upward, thereby driving the lever system 4 to extend radially into a < shape, so as to suspend and support the filter string 11 at the cut at the lower end of the cutting chamber 13; at the same time, the spring seat 7 carries the sealing assembly 8 and inserts it into the well barrel below the cut to achieve a seal.

[0030] In one possible implementation, the connector is a cylinder with internal threads at both ends. The upper internal thread is used to form a rigid connection with the filter, and the lower internal thread is connected to the cylinder body. The top external thread of the cylinder body is connected to the connector. As the core load-bearing component, the outer wall is provided with a lever system mounting hinge, mounting groove and push ring (spring) positioning step, and the bottom external thread forms a sealed connection with the spring seat.

[0031] The device also includes a hinge assembly, which may contain eight sets of hinge seats. The upper four sets of hinge seats are evenly distributed at 90° angles on the outer cylindrical surface of the cylinder, and the lower four sets of hinge seats are evenly distributed at 90° angles on the outer cylindrical surface of the push ring. Each set of hinge seats consists of two identical isosceles trapezoidal steel plates with a through hole in the middle, arranged at intervals. They are fixed to a specified height on the cylinder by welding. The diameter of the hinge seat hole and the diameter of the lever connection end form an H7 / h6 clearance fit. The hinge seat material is 316L stainless steel.

[0032] The upper lever has square steel bars with through holes machined at both ends. A raised square block is milled at the upper end, with a circular through hole machined in the center of the raised block. A deep square groove is milled at the lower end, with circular through holes machined in the centers of the upper and lower groove walls. The two ends of the lever form rotating pairs with the cylinder hinge seat and the lower lever, respectively. The upper lever can be made of 45# steel with a hardness of HRC30-34 after tempering.

[0033] The pin is a short cylinder with retaining ring grooves at both ends. After aligning the upper and lower lever connection holes, the pin is inserted, and the retaining rings (elastic retaining rings for the shaft) are engaged in the retaining ring grooves at both ends of the pin, fixing the pin in place and preventing it from coming out. The pin material can be 42CrMo.

[0034] The lower lever has square steel bars with through holes at both ends, and milled protruding square blocks at both ends. A circular through hole is machined in the center of each protruding square block. The upper end connects to the upper lever via a connecting hole, and the lower end is assembled to the push ring hinge via a connecting hole. The lower lever can be made of 45# steel with a hardness of HRC30-34 after tempering.

[0035] The push ring can be made of 45# steel, with four threaded holes evenly distributed around its circumference, and the surface is heat-treated (HRC28-32). The spring can be made of 60Si2MnA spring steel, with a pre-compression controlled within the range of 50-70mm. The upper end tightly presses against the lower end face of the push ring to provide continuous thrust for retraction. The upper part of the spring seat is machined with internal threads to form a metal-sealed connection with the cylinder. The outer diameter of the spring seat is larger than the outer diameter of the lower end of the cylinder, and the spring sits on the upper end of the spring seat. An annular groove is provided in the middle for installing three sets of Y-shaped sealing rings. The lower end face is chamfered at 45° for easy insertion into the well shaft. The Y-shaped sealing ring set can be made of nitrile rubber with a Shore hardness of 70±5HA, installed with the V-shaped opening facing upwards, and the compression rate is maintained at 15-20%.

[0036] See Figure 3 The apparatus disclosed herein shall be implemented by following the steps described above.

[0037] The assembly stage of the device includes: connector connection, connecting and tightening the lower internal thread of connector 1 to the upper external thread of the upper end of cylinder 2; push ring installation, fitting push ring 5 onto cylinder 2 from the lower end, allowing push ring 5 to slide freely axially on the outer cylindrical surface between the lower end of cylinder 2 and the limiting step; spring installation, fitting the pre-compressed spring 6 into cylinder 2, ensuring that the lower end of the spring is in contact with the upper end face of spring seat 7; and spring seat installation, screwing spring seat 7 into the lower external thread of cylinder 2 through its internal thread.

[0038] The lever system assembly includes: the upper end of the upper lever 4 is connected to the cylinder hinge seat 3 by a pin through the round hole on the square protrusion, and the lower end is connected to the round hole on the square protrusion at the upper end of the lower lever 4 by a cylindrical pin through the round hole on the square slot wall; the lower end of the lower lever 4 forms a rotating pair with the hinge seat of the push ring 5 by bolts.

[0039] The sealing system installation includes: sequentially installing two sets of Y-shaped triple sealing rings 8 into the annular groove of the spring seat 7, applying silicone-based grease, and then using a special tool to evenly press the V-shaped opening of the sealing ring into the groove.

[0040] During the downhole operation phase, the entire device is connected to the lower end of the filter string 11 via the threaded connection of connector 1, and then the drill pipe 9 is connected to the upper end of the filter string 11 via the retractable safety connector 10. During the lowering process, the filter string 11 and the entire device are slowly lowered to the design depth via the drill pipe 9. During the lowering process, the rod system 4 is constrained by the pressure of the well wall 12, and the rod system 4 extends axially and contracts radially. The middle hinge of the upper and lower levers is approximately parallel to the axis of the cylinder 2 and protrudes slightly outward to press against the well wall. The push ring 5 is at the lower stop point, and the spring 6 is compressed.

[0041] Entering the cutting chamber: When the entire device is lowered into the cutting chamber 13, due to the increase in well diameter, the lever system 4 is no longer constrained by the inner wall 12 of the well. As a result, the compressed spring 6 pushes the push ring 5 to move axially upward along the outer cylindrical surface of the cylinder 2, pushing the upper and lower sections of the lever system 4 to extend radially through the intermediate hinge in a < shape. After all four sets of levers extend radially, they resemble a lantern.

[0042] Positioning and locking: When the chamfered surface of the lower end of the spring seat 7 contacts the inner wall of the well barrel below the cutting cavity 13, it continues to be lowered. The four sets of radially extending levers of the lever system 4 suspend and support the filter string 11 at the well barrel opening at the lower end of the cutting cavity 13. At the same time, the sealing ring 8 in the groove of the outer circular surface of the sealing seat 7 is fully compressed by the inner wall of the well barrel to form an annular sealing barrier, and the sealing spring seat is annular with the well barrel.

[0043] Pocket Formation: After the fixing port is installed at the lower end of the cutting cavity 13, a sand-collecting pocket will naturally form in the wellbore space below the device. The effective volume formed is calculated to be ≥0.3m³. 3 The volume of sediment is much larger than the previous 0.015m3-0.02m3, increasing by 15-20 times.

[0044] The disclosed device innovatively integrates three core functions: suspension support, annular sealing, and sand-filled bag expansion. With a single running operation, it simultaneously achieves reliable suspension and fixation of the filter at the cutting chamber incision, reliable sealing between the device and the wellbore annulus, and effective utilization of the wellbore space below, greatly simplifying the downhole tubing structure and operational procedures.

[0045] The device employs a spring-driven lever deployment mechanism, enabling automatic triggering and locking of the suspension function. During the lowering process, the lever system remains contracted due to the constraint of the well wall; upon entering the cutting chamber, the well diameter increases, the spring automatically releases, pushing the push ring upwards, forcing the lever system to deploy radially into a "lantern" shape, forming a stable and reliable mechanical support point. This firmly suspends and supports the filter string in the predetermined position, avoiding the problems of unstable support or the need for complex ground operations that may exist in traditional methods.

[0046] Multiple Y-shaped sealing rings are arranged in the middle of the spring seat to form a multi-stage, self-tightening sealing barrier. Once the device is in place, the sealing rings are compressed by the inner wall of the wellbore, and their V-shaped structure effectively adapts to changes in the annulus size, achieving a reliable seal. This design effectively prevents gravel and rock cuttings in the cutting chamber from sinking through the annulus between the device and the wellbore, preventing them from clogging the lower sand-collecting bag or entering deeper sections of the well, thus ensuring the functional integrity of the filter and sand-collecting bag.

[0047] By sealing the wellbore below the device and using it as a sedimentation bag, its effective volume (≥0.3m³) is increased. 3 Compared to traditional small-capacity pockets (0.015-0.02m) 3 This represents a 15-20 fold increase. It significantly increases the capacity to hold drilling debris and formation sand, substantially extends the work cycle between two filter maintenance and sand removal operations, reduces the frequency of tripping in and out of the drill string, and improves the borehole's production efficiency and economic benefits.

[0048] In addition, the keyway-positioning pin fit between the push ring and the cylinder ensures that the push ring can only slide axially and cannot rotate, making the lever unfolding process smooth, synchronous, and with uniform force.

[0049] All components (such as the joint-cylinder and the cylinder-spring seat) are connected by threads, resulting in a compact structure and strong load-bearing capacity. The lower end of the spring seat is designed with a guide chamfer, and the lever system can automatically retract during lowering, reducing the risk of obstruction downhole and improving the smoothness of lowering.

[0050] The device disclosed herein is designed for the special wellbore structure of in-situ immersion boreholes with cutting windows, effectively addressing the challenges of filter installation and sealing in such wells. The selection of materials (e.g., tempered 45# steel, stainless steel, nitrile rubber) and process design (e.g., pre-compression springs, specific hardness) for key components (such as levers, hinges, and sealing rings) fully considers the harsh environment of downhole corrosion, wear, and long-term pressure, ensuring the device's durability and long-term sealing reliability.

[0051] The various embodiments of this disclosure have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or improvement of the technology in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A hanger support and pocket connection seal apparatus for a cutting drilling in-line filter, connected to the lower end of the filter string, characterized by, The device comprises a joint (1), a cylinder (2), a lever system (4), a push ring (5), a spring (6) and a spring seat (7); The upper end of the joint (1) is used for connecting a filter string (11); The cylinder (2) is connected with the lower end of the joint (1) at the upper end; The lever system (4) comprises an upper lever (4-1) and a lower lever (4-3) which are connected by a pin shaft (4-2), and the upper end of the upper lever (4-1) is hinged to the upper part of the outer wall of the cylinder (2); The push ring (5) is sleeved on the outside of the cylinder (2) and can slide axially along the cylinder (2), and the outer wall of the push ring (5) is hinged with the lower end of the lower lever (4-3); The spring (6) is sleeved on the outside of the cylinder (2) and is located below the push ring (5), and is used for providing elastic force for sliding the push ring (5) upward along the cylinder (2); The spring seat (7) is connected with the lower end of the cylinder (2) and is used for providing lower end support for the spring (6); Wherein, the outer wall of the spring seat (7) is provided with an annular sealing groove, and a sealing assembly (8) for sealing the annular space between the spring seat (7) and the inner wall of the wellbore is installed in the groove; When the device is lowered into the cutting cavity (13), the spring (6) pushes the push ring (5) to move upward, thereby driving the lever system (4) to extend radially to present a < shape, so as to support the filter string (11) at the cutout at the lower end of the cutting cavity (13); at the same time, the spring seat (7) carries the sealing assembly (8) to insert into the wellbore below the cutout, so as to realize sealing.

2. The apparatus of claim 1, wherein, The upper half of the device is located in the cutting cavity (13), and the lower half is inserted into the wellbore below the cutting cavity (13).

3. The apparatus of claim 1, wherein, The upper part of the outer wall of the cylinder (2) is uniformly distributed with a plurality of first hinge seats (3) in the circumferential direction, and the upper end of the upper lever (4-1) is hinged with the first hinge seat (3) through the pin shaft (4-2); the outer wall of the push ring (5) is uniformly distributed with a plurality of second hinge seats in the circumferential direction, and the lower end of the lower lever (4-3) is hinged with the second hinge seat through the pin shaft (4-2) or bolt.

4. The apparatus of claim 1, wherein, The outer wall of the cylinder (2) is provided with an axial key groove, and the inner wall of the push ring (5) is provided with a positioning pin matched with the key groove, so that the push ring (5) can slide axially along the cylinder (2) but cannot rotate relatively.

5. The apparatus of claim 1, wherein, The spring (6) is a pre-compressed spring, and the pre-compression amount ranges from 50 mm to 70 mm.

6. The apparatus of claim 1, wherein, The spring seat (7) is cylindrical, and the upper end thereof is connected with the outer thread of the lower end of the cylinder (2) through the inner thread; the lower end of the spring seat (7) is provided with a guide chamfer on the outer edge.

7. The apparatus of claim 1, wherein, The sealing assembly (8) comprises a plurality of Y-shaped sealing rings installed in the annular sealing groove of the spring seat (7), and the V-shaped opening of the Y-shaped sealing ring is arranged upward.

8. The apparatus of claim 7, wherein, The Y-shaped sealing ring is made of butyronitrile rubber, and the compression rate is kept at 15% to 20%.

9. The device of any one of claims 1 to 9, wherein, When the device is installed in place, the wellbore space below the spring seat (7) constitutes a sand pocket, and the effective volume thereof is not less than 0.3 cubic meters.

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