A flexible composite tube perforating and slitting apparatus and method for use in in-situ leaching mining

Abstract

The application discloses a flexible composite pipe perforating and slitting device and method in in-situ leaching mining, which comprises a downhole tool string, a wellhead device and a flexible continuous pipe arranged in a wellbore; the downhole tool string comprises a spray gun, an instrument bin and a safety joint which are sequentially connected; the flexible continuous pipe is composed of a structural layer, a fiber woven reinforcing layer, a signal layer, a high-strength polymer tensile layer and the like, has a flexible bending capacity, can adapt to a pipeline with a certain bending deformation, can be flexibly moved in an inclined track of the wellbore, combines the performance advantages of different layer materials, is suitable for pipeline conveying scenes with requirements for flexibility, corrosion resistance and the like, and replaces ordinary oil pipes with the flexible continuous pipe, thereby avoiding cumbersome operations of connecting the oil pipes one by one, and realizing automatic and continuous tripping of the flexible continuous pipe by a ground pipeline winch in cooperation with a pipeline conveyor, so that automatic operation is realized, manual intervention time is reduced, and operation time is significantly shortened.

Description

Technical Field

[0001] This invention relates to the field of in-situ leaching mining technology, specifically to a flexible composite pipe perforation and slotting device and method used in in-situ leaching mining. Background Technology

[0002] Currently, in in-situ leaching mining, the existing hydraulic jet perforation technology uses tubing of approximately 9.75m in length with a diameter of φ60.3mm, φ73mm, or φ88.9mm as the construction string. Cranes or workover rigs are used for the tubing string tripping operations. This method suffers from problems such as long operation time, casing damage, and high safety risks. For example, a 1000-meter in-situ leaching uranium production well requires 103 tubing strings. The average operation time for each tubing string is 3.5 minutes, and a round trip trip takes 721 minutes, approximately 12 hours. The casing used in in-situ leaching uranium wells is made of PVC. During drilling, the wellbore inevitably exhibits some deviation. The rigid tubing exerts a radial force on the PVC casing. This radial force, combined with formation stress, can cause the PVC casing to rupture if it exceeds the strength of the PVC material. Workers operating and connecting tubing at the wellhead not only experience high labor intensity but also face safety risks such as mechanical injury, being struck by objects, and falling debris. Furthermore, using ordinary tubing also presents the problem of not being able to monitor the construction progress in real time. Summary of the Invention

[0003] The purpose of this invention is to provide a flexible composite pipe perforation and slotting device and method for in-situ leaching mining in order to solve the above-mentioned problems and overcome the defects of the prior art, as detailed below.

[0004] To achieve the above objectives, the present invention provides the following technical solution:

[0005] The present invention provides a flexible composite pipe perforation and slotting device for in-situ leaching mining, comprising a downhole tool string, wellhead equipment, and a flexible continuous pipe installed in the wellbore;

[0006] The downhole tool string includes a spray gun, an instrument compartment, a safety connector, and a roller-type depth recorder connected in sequence.

[0007] The wellhead equipment includes a wellhead tee, on which a pipeline conveyor for controlling the raising and lowering of the flexible continuous tubing inside the casing is installed, and a self-sealing wellhead sealer for sealing the annulus between the flexible continuous tubing and the casing is installed between the wellhead tee and the pipeline conveyor.

[0008] It also includes ground pipeline winches, used for winding and unwinding flexible continuous pipes, and used in conjunction with pipeline conveyors to assist in the lifting and lowering of flexible continuous pipes.

[0009] Preferably, the flexible continuous tube consists of a structural layer, a reinforcing layer, a signal layer, a tensile layer, and a protective layer. The reinforcing layer adopts a fiber braided structure, and the tensile layer is made of a high-strength polymer material.

[0010] Preferably, the instrument compartment includes a first eccentric flow channel and an instrument mounting cavity for mounting a sensor assembly.

[0011] Preferably, the sensor group includes at least one of a depth measurement sensor, a natural gamma sensor, a pressure sensor, a temperature sensor, and a wellbore image monitoring sensor.

[0012] Preferably, the ground pipeline winch includes a support frame, on which a pipeline winding wheel is rotatably mounted, and a motor is fixedly mounted on the support frame. The output shaft of the motor is connected to the shaft of the pipeline winding wheel via a sprocket transmission mechanism.

[0013] Preferably, one end of the flexible continuous tube wound on the pipeline winding wheel is rotatably connected to a liquid receiving head via a rotary sealing joint, and the liquid receiving head is fixedly mounted on the support frame by a fixed bracket.

[0014] Preferably, a safety connector capable of emergency disconnection is provided between the flexible continuous tube and the instrument compartment, and a signal line for connecting to the ground signal collection controller is laid inside the tube wall of the flexible continuous tube.

[0015] Preferably, the roller-type depth recorder includes a housing, a second eccentric flow channel is formed inside the housing, a mounting compartment is provided on one side of the outer side of the housing, and a signal cable groove communicating through the mounting compartment is also provided on the outer side of the housing. A Hall sensor and a roller structure are respectively provided in the mounting compartment.

[0016] Preferably, the roller structure includes a deflection wheel rod, one end of which is rotatably mounted in the mounting chamber via a rotating shaft, and the other end of which is rotatably connected to a roller capable of rolling against the sleeve along its axial direction. A permanent magnet is provided on the outer side of the roller, and an anti-slip ring is fitted on the outer side of the roller. A spring plate is provided between the deflection wheel rod and the inner sidewall of the mounting chamber.

[0017] A flexible composite pipe perforation and slotting device and method for in-situ leaching mining includes the following steps:

[0018] S1: The downhole tool string is connected to the surface pipeline winch via a flexible coiled tube. The pipeline conveyor enables the raising and lowering of the flexible coiled tube and the downhole tool string within the casing. The sensor in the instrument compartment monitors and controls the position of the spray gun in real time, while simultaneously collecting downhole parameters during the perforation and slotting process.

[0019] S2: The working fluid is prepared by the ground sand mixing system and the pump pressure is increased to 25-55MPa by the plunger booster pump. The sand-carrying fluid is sprayed out from the 0-10° tilt nozzle of the spray gun through the flexible continuous pipe, impacting the casing and the formation to form perforation holes and slots.

[0020] S3: After the perforation operation is completed, switch the well-washing channel of the spray gun by dropping a ball to pressurize and flush the well with clean water at a discharge rate of 0.2-3 m³ / min until the sand content of the returned fluid is <0.5%;

[0021] S4: The flexible continuous pipe is raised and lowered by a ground pipeline winch and pipeline conveyor. The raising and lowering speed is controlled at 10-25m / min. A booster pump is connected through a liquid receiving head. The roller-type depth recorder can measure the descent height of the spray gun.

[0022] The beneficial effects are:

[0023] 1. By replacing ordinary oil pipes with flexible continuous tubing, the tedious operation of connecting oil pipes one by one is avoided. The flexible continuous tubing is automatically and continuously raised and lowered by a ground pipeline winch and pipeline conveyor, realizing automated operation, reducing the time spent on manual intervention, and significantly shortening the operation time.

[0024] 2. Flexible continuous tubing consists of a structural layer, a fiber braided reinforcement layer, a signal layer, and a high-strength polymer tensile layer. It has flexible bending capabilities and can adapt to certain bending deformations. It can move flexibly in the wellbore's inclined trajectory. Combining the performance advantages of different layer materials, it is suitable for pipeline transportation scenarios that require flexibility and corrosion resistance. It reduces the radial force on the PVC casing and avoids casing rupture caused by the superposition of formation stress. Compared with traditional rigid tubing, flexible tubing has less friction and compression on the inner wall of the casing during the tripping process, and is especially suitable for PVC casing protection in in-situ leaching uranium wells.

[0025] 3. No need for frequent manual connection of tubing, avoiding risks such as mechanical injury, falling objects, and falling objects during wellhead operations, reducing the labor intensity of workers. The self-sealing wellhead sealer seals the annulus between the flexible continuous tubing and the casing to prevent leakage of high-pressure sand-carrying fluid, avoiding environmental pollution and safety accidents. The safety joint can be detached in case the downhole tool string gets stuck, protecting the equipment and safety of operations in the well.

[0026] 4. The sensor group in the instrument compartment, including depth measurement, pressure, temperature, natural gamma, and well wall image, collects downhole data in real time during the perforation and slotting process. The data is transmitted to the ground controller through the signal line in the flexible tube, which helps the construction personnel to accurately control the position of the spray gun and adjust the parameters. The construction effect can be monitored in real time, and problems such as casing deformation and poor perforation effect can be detected and solved in time, thus ensuring the construction quality.

[0027] 5. During construction, the flexible continuous pipe has great extensibility and is sensitive to pressure. Under pressure, the flexible continuous pipe will elongate. The length of the pipe measured by the pipeline conveyor at the wellhead is the length of the pipe when the pressure is low. At this time, the Hall sensor, together with the permanent magnet on the outside of the roller, can realize the real-time measurement of the descent depth, thereby reducing the position error. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is the front view of the present invention;

[0030] Figure 2 This is the present invention. Figure 1 First-direction stereoscopic view;

[0031] Figure 3 This is the present invention. Figure 1 The second-direction stereoscopic view;

[0032] Figure 4 This is a cross-sectional view of the instrument compartment of the present invention;

[0033] Figure 5 This is a perspective view of the roller-type depth recorder of the present invention;

[0034] Figure 6 This is a cross-sectional view of the roller-type depth recorder of the present invention.

[0035] The reference numerals in the attached drawings are explained as follows: 1. Casing; 2. Wellhead tee; 201. Seat plate; 3. Flexible continuous tubing; 301. Rotary sealing joint; 302. Liquid receiving head; 303. Fixed bracket; 4. Surface pipeline winch; 401. Support frame; 402. Pipeline winding wheel; 403. Motor; 404. Sprocket drive mechanism; 5. Pipeline conveyor; 6. Instrument compartment; 601. First eccentric flow channel; 602. Instrument mounting cavity. 603. Cover plate; 7. Spray gun; 8. Safety joint; 9. Self-sealing well sealer; 10. Roller-type depth recorder; 1001. Housing; 1002. Mounting chamber; 1003. Signal cable tray; 1004. Deflection wheel rod; 1005. Roller; 1006. Permanent magnet; 1007. Hall sensor; 1008. Spring plate; 1009. Anti-slip collar; 1010. Rotating shaft; 1011. Second eccentric flow channel. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be described in detail below. Obviously, the described embodiments are merely some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other implementation methods obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0037] See Figures 1-6 As shown, the present invention provides a flexible composite pipe perforation and slotting device for in-situ leaching mining, including a downhole tool string, wellhead equipment, and a flexible continuous pipe 3 installed in the wellbore;

[0038] The downhole tool string includes a spray gun 7, an instrument compartment 6, a safety connector 8, and a flexible coiled tubing 3 connected in sequence. A signal cable for connection to a surface signal acquisition controller is laid inside the flexible coiled tubing 3. The safety connector 8 enables emergency detachment between the instrument compartment 6 and the flexible coiled tubing 3. The safety connector 8 utilizes existing technology, such as a shear pin structure, and can withstand a tensile and shear force of 20 tons, possessing an emergency detachment function, which is well-known to those skilled in the art. When the downhole tool string becomes stuck downhole, such as by rock debris or casing deformation and compression, the safety connector 8 can achieve emergency detachment through the pre-set shear pin structure, preventing the entire flexible coiled tubing 3 from being unrecoverable and protecting the equipment and operational safety in the well.

[0039] See instruction manual attached Figure 1 and Figure 2 As shown, the wellhead equipment includes a wellhead tee 2, on which a pipeline conveyor 5 is installed to control the raising and lowering of the flexible coiled tubing 3 within the casing 1. A self-sealing wellhead sealer 9 is installed between the wellhead tee 2 and the pipeline conveyor 5 to seal the annulus between the flexible coiled tubing 3 and the casing 1. In practical applications, the self-sealing wellhead sealer 9 employs existing technology, well-known to those skilled in the art. It relies on the pressure of the annular space within the well and the expansion and contraction capacity of the rubber core to seal the annulus between the flexible coiled tubing 3 and the casing 1, preventing leakage of high-pressure sand-carrying fluid and other fluids within the well, avoiding the spillage of oily or wastewater and ensuring operational safety. For example, during hydraulic jetting perforation and slotting operations, it prevents high-pressure sand-carrying fluid from overflowing from the wellhead, ensuring a safe working environment and smooth construction. It also includes a surface pipeline winch 4, used for winding and unwinding the flexible coiled tubing 3, assisting the raising and lowering of the flexible coiled tubing 3 in conjunction with the pipeline conveyor 5.

[0040] The flexible coiled tubing 3 consists of a structural layer, a reinforcing layer, a tensile layer, and a protective layer. The reinforcing layer uses a fiber braided structure, and the tensile layer is made of high-strength polymer material. The flexible coiled tubing 3 possesses flexibility, allowing it to bend flexibly along the wellbore's inclined trajectory, reducing radial forces on the casing 1, preventing casing 1 from rupturing, and preventing self-jamming. The casing 1 is made of PVC material. The automated tripping operation of the flexible coiled tubing 3 eliminates the need for frequent manual tubing connections, reducing contact between wellhead personnel and high-risk machinery, lowering safety hazards such as falling objects and mechanical injuries, and significantly saving operation time.

[0041] See instruction manual attached Figure 4 As shown, the instrument compartment 6 includes a first eccentric flow channel 601 and an instrument mounting cavity 602 for installing a sensor assembly. One side of the instrument mounting cavity 602 is open, and a cover plate 603 is provided at the opening. The sensor assembly includes at least one of a depth measurement sensor, a natural gamma sensor, a pressure sensor, a temperature sensor, and a wellbore image monitoring sensor. This structure enables real-time monitoring and transmission of key parameters such as drilling depth, pressure, temperature, and natural gamma. Simultaneously, wellbore observation is conducted using the instrument compartment 6, allowing operators to promptly grasp downhole dynamics and accurately adjust drilling parameters. Compared to traditional tubing hydraulic blasting perforation and slotting operations, this technology fills the gap of lacking real-time data feedback during the drilling process, providing dual protection for drilling quality and downhole safety.

[0042] See instruction manual attached Figure 2 and Figure 3 As shown, the ground pipeline winch 4 includes a support frame 401, on which a pipeline winding wheel 402 is rotatably mounted. A motor 403 is fixedly mounted on the support frame 401, and the output shaft of the motor 403 is connected to the shaft end of the pipeline winding wheel 402 via a sprocket transmission mechanism 404. One end of the flexible continuous pipe 3 wound on the pipeline winding wheel 402 is rotatably connected to a liquid receiving head 302 via a rotary sealing joint 301. The liquid receiving head 302 is fixedly mounted on the support frame 401 via a fixed bracket 303. In practical applications, the ground pipeline winch 4 can be placed on a semi-trailer for easy relocation.

[0043] See instruction manual attached Figure 2 and Figure 6As shown, the roller-type depth recorder 10 includes a housing 1001, within which a second eccentric flow channel 1011 is formed. A mounting chamber 1002 is located on one side of the housing 1001. A signal cable groove 1003, communicating through the mounting chamber 1002, is also provided on the outer side of the housing 1001. A Hall sensor 1007 and a roller structure are respectively installed inside the mounting chamber 1002. The roller structure includes a deflection rod 1004. One end of the deflection rod 1004 is rotatably mounted inside the mounting chamber 1002 via a rotating shaft 1010. The other end of the deflection rod 1004 is rotatably connected to a roller 1005 capable of rolling against the sleeve 1 along its axial direction. A permanent magnet 1006 is provided on the outer side of the roller 1005, and an anti-slip ring 1009 is fitted on the outer side of the roller 1005. A spring plate 1008 is provided between the deflection rod 1004 and the inner wall of the mounting chamber 1002. Through the above-described structural design, with the elastic contact of the spring plate 1008 against the deflection wheel rod 1004, the roller 1005 can make close contact with the inner wall of the casing 1, and with the cooperation of the anti-slip ring 1009, achieve non-slip rolling with the inner wall of the casing 1. When the roller 1005 rotates, the permanent magnet 1006 on its outer side rotates accordingly, and the Hall sensor 1007 detects this, thus obtaining the descent depth. During construction, the flexible continuous pipe 3 has high extensibility and is sensitive to pressure. During the hydraulic sandblasting perforation and slotting process, it is necessary to control the position and reduce positional errors. During the pipe lowering process, there is no pressure inside the pipe. When the spray gun 7 reaches the ore layer position, the pressure inside the flexible continuous pipe 3 needs to rise to 40MPa. Under pressure, the flexible continuous pipe 3 will elongate. The length of the pipe measured by the wellhead wheel is the length of the pipe under low pressure. At this time, the Hall sensor 1007, in conjunction with the permanent magnet 1006 on the outer side of the roller 1005, can realize real-time measurement of the descent depth, thereby solving the above problems and reducing positional errors.

[0044] Working principle of the invention:

[0045] The downhole tool string is connected to the surface pipeline winch 4 via a flexible coiled tubing 3. The pipeline conveyor 5 enables the raising and lowering of the flexible coiled tubing 3 and the downhole tool string within the casing 1. Sensors in the instrument compartment 6 monitor and control the position of the spray gun 7 in real time, while simultaneously collecting downhole parameters during the perforation and slotting process. The working fluid is prepared by the surface sand mixing system and the pump pressure is increased to 25-55 MPa by a plunger booster pump, causing the sand-carrying fluid to be ejected from the 0-10° angle nozzle of the spray gun 7 through the flexible coiled tubing 3, impacting the casing 1 and the formation to form perforation holes and slots. After the perforation operation is completed, the spray gun well-washing channel is switched by ball dropping and pressurizing, and clean water is used for positive circulation well-washing at a discharge rate of 0.2-3 m³ / min until the sand content of the returned fluid is <0. 5%; The flexible continuous tube 3 is raised and lowered using a ground pipeline winch 4 and a pipeline conveyor 5 in conjunction. The raising and lowering speed is controlled at 10-25 m / min. A booster pump is connected through a liquid receiving head 302. The roller-type depth recorder 10 can measure the descent height of the spray gun 7. In practical applications, the pipeline conveyor 5 adopts existing technology. It can measure the descent length of the flexible continuous tube 3, and the roller-type depth recorder 10 can directly measure the descent depth of the spray gun 7. The pipeline conveyor 5 and the roller-type depth recorder 10 assist each other. Under a certain descent depth, the deformation of the flexible continuous tube 3 at that depth is compared with the descent depth to accurately determine the descent height of the spray gun 7.

[0046] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A flexible composite pipe perforation and slotting device for in-situ leaching mining, characterized in that: Includes downhole tool strings, wellhead equipment, and flexible coiled tubing installed in the wellbore (3); The downhole tool string includes a spray gun (7), an instrument compartment (6), a safety connector (8), and a roller-type depth recorder (10) connected in sequence. The wellhead equipment includes a wellhead tee (2), on which a pipeline conveyor (5) is provided for controlling the flexible continuous pipe (3) to move up and down inside the casing (1), and a self-sealing well sealer (9) is provided between the wellhead tee (2) and the pipeline conveyor (5) for sealing the annulus between the flexible continuous pipe (3) and the casing (1). It also includes a ground pipeline winch (4) for winding and unwinding the flexible continuous pipe (3), and a pipeline conveyor (5) to assist in the lifting and lowering of the flexible continuous pipe (3); The roller-type depth recorder (10) includes a housing (1001), a second eccentric flow channel (1011) is formed inside the housing (1001), an installation compartment (1002) is provided on one side of the outer side of the housing (1001), and a signal cable groove (1003) communicating through the installation compartment (1002) is also provided on the outer side of the housing (1001). A Hall sensor (1007) and a roller structure are respectively provided inside the installation compartment (1002). The roller structure includes a deflection wheel rod (1004), one end of which is rotatably mounted in the mounting chamber (1002) via a rotating shaft (1010). The other end of the deflection wheel rod (1004) is rotatably connected to a roller (1005) that can roll against the sleeve (1) along its axial direction. A permanent magnet (1006) is provided on the outer side of the roller (1005), and an anti-slip ring (1009) is fitted on the outer side of the roller (1005). A spring plate (1008) is provided between the deflection wheel rod (1004) and the inner wall of the mounting chamber (1002).

2. The flexible composite pipe perforation and slotting device for in-situ leaching mining according to claim 1, characterized in that: The flexible continuous tube (3) consists of a structural layer, a reinforcing layer, a signal layer, a tensile layer and a protective layer. The reinforcing layer adopts a fiber braided structure and the tensile layer is made of a high-strength polymer material.

3. A flexible composite pipe perforation and slotting device for in-situ leaching mining according to claim 1 or 2, characterized in that: The instrument compartment (6) includes a first eccentric flow channel (601) and an instrument mounting cavity (602) for mounting a sensor assembly.

4. The flexible composite pipe perforation and slotting device for in-situ leaching mining according to claim 3, characterized in that: The sensor group includes at least one of a depth measurement sensor, a natural gamma sensor, a pressure sensor, a temperature sensor, and a wellbore image monitoring sensor.

5. The flexible composite pipe perforation and slotting device for in-situ leaching mining according to claim 1, characterized in that: The ground pipeline winch (4) includes a support frame (401), on which a pipeline winding wheel (402) is rotatably mounted, and a motor (403) is fixedly mounted on the support frame (401). The output shaft end of the motor (403) is connected to the shaft end of the pipeline winding wheel (402) through a sprocket transmission mechanism (404).

6. The flexible composite pipe perforation and slotting device for in-situ leaching mining according to claim 5, characterized in that: One end of the flexible continuous tube (3) wound on the pipeline winding wheel (402) is sealed and rotatably connected to the liquid receiving head (302) through a rotary sealing joint (301). The liquid receiving head (302) is fixedly mounted on the support frame (401) by a fixed bracket (303).

7. A flexible composite pipe perforation and slotting device for in-situ leaching mining according to claim 1 or 6, characterized in that: The safety connector (8) is located between the flexible continuous tube (3) and the instrument compartment (6) for emergency detachment. The flexible continuous tube (3) has a signal line laid inside its wall for connection with the ground signal collection controller.

8. A method for perforating and slotting using flexible composite pipes in leaching mining, employing the flexible composite pipe perforating and slotting equipment for leaching mining as described in any one of claims 1-7, characterized in that: Includes the following steps: S1: The downhole tool string is connected to the surface pipeline winch (4) through the flexible continuous tube (3). The pipeline conveyor (5) realizes the raising and lowering of the flexible continuous tube (3) and the downhole tool string in the casing (1). The sensor in the instrument compartment (6) is used to monitor and control the position of the spray gun (7) in real time, and at the same time, the downhole parameters during the perforation and slotting process are collected. S2: The working fluid is prepared by the ground sand mixing system and the pump pressure is increased to 25-55MPa by the plunger booster pump. The sand-carrying fluid is sprayed out from the 0-10° tilt nozzle of the spray gun (7) through the flexible continuous pipe (3) to impact the casing (1) and the formation to form perforation holes and slots. S3: After the perforation operation is completed, switch the well-washing channel of the spray gun by dropping a ball to pressurize and flush the well with clean water at a discharge rate of 0.2-3 m³ / min until the sand content of the returned fluid is <0.5%; S4: The flexible continuous pipe (3) is raised and lowered by a ground pipeline winch (4) and a pipeline conveyor (5). The raising and lowering speed is controlled at 10-25m / min. A booster pump is connected through a liquid receiving head (302). The roller-type depth recorder (10) can measure the descent height of the spray gun (7).

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