A double-layer pipe lifting tool for reverse circulation bottom drainage

Abstract

The present invention discloses a double-layer pipe lifting tool for reverse circulation bottom-hole drainage assistance, which includes three parts: a locking track mechanism, a core replacement mechanism and a diversion mechanism. The locking track mechanism is composed of a self-locking track, an inner tube, etc.; the core replacement mechanism is composed of a suction nozzle, a diversion nozzle, etc.; the diversion mechanism is composed of an inner pipe joint, a reverse thrust spring, etc. The upper pipe column joint, the inner tube and the lower pipe column joint are respectively connected to the upper and lower pipe column joints, the bottom end of the locking track mechanism is connected to the top end of the diversion mechanism, and the core replacement mechanism is clamped in the locking track mechanism and the diversion mechanism through a self-locking protrusion. The present invention adopts the jet lifting principle to improve the migration speed and fluidity of the return fluid, realizes the drainage and lifting of the mixed slurry with high sand content and large-sized rock cuttings in the well, and effectively prevents the occurrence of pump jamming; a core replacement mechanism is set to realize the remote replacement of the downhole pump core, and different specifications of pump cores can be replaced according to process requirements to change the lift and pump pressure of the lifting tool, and meet the requirements of replacing the pump core erosion in the application, thereby improving the production operation efficiency and safety.

Description

Technical Field

[0001] The invention belongs to the field of energy mining equipment, and in particular relates to a reverse circulation well bottom drainage-aiding double-layer pipe lifting tool. Background Art

[0002] In recent years, due to the increasing demand for resources such as oil and natural gas in social production and life, the exploitation depth of oil and natural gas resources has been increasing. The annular pressure in the lower part of the land well increases with the depth. In the development of deepwater oil, gas and hydrates, there is a narrow density window in the shallow surface drilling, and the formation is loose and soft and easy to leak. The pressure in the wellbore needs to be precisely controlled during the drilling process, otherwise it is easy to cause the well wall to become unstable, and a well leakage accident occurs, affecting the drilling efficiency. At present, methods such as configuring drilling fluid, using gas, inflation, and foaming are commonly used to control the pressure of the wellbore liquid column, but these methods are difficult to implement, and each has mutually matching process requirements, and the applicability is poor. The existing patent CN 101725543 A proposes an annular turbine suction pump, which drives the internal turbine to rotate through the drilling fluid, drives the outer turbine pump blades to rotate, and realizes the lifting of the drilling fluid, but the turbine blades are exposed outside, so that the tool cannot be used in most complex well sections, which is very restrictive.

[0003] Horizontal wells and extended-reach wells are currently widely used in the fields of oil, natural gas, shale gas and natural gas hydrate exploitation. However, the rock cuttings generated during the drilling process and the large amount of sand and gravel brought out by the flow of oil and gas during the production process, the rock cuttings or sand and gravel are easily deposited on the lower well wall of horizontal wells, high-angle wells, extended-reach wells, complex structure wells, etc. under the action of gravity. In the daily drilling process, if the mixed slurry migration cannot be well achieved and the flow rate of the annular return fluid cannot be increased, the accumulation of rock cuttings or sand and gravel will form a rock cutting bed or sand settling, which greatly affects the efficiency and safety of the drilling and completion process. The existing patent CN 112482986 A proposes a downhole hydraulic lifting tool, in which the drilling fluid flowing in the drill pipe drives the turbine power mechanism to rotate, and the screw axial flow mechanism rotor is driven to rotate through the turbine center shaft and the universal joint mechanism to achieve the lifting of the annular drilling fluid and the migration of the horizontal section annular cuttings, but its structure is complex, the efficiency is low, the life is short, and it is easy to get stuck in the pump and pipeline blockage.

[0004] At the same time, through the investigation of various types of pumps that can be used for underground lifting, it was found that none of them can meet the drainage operations such as reverse circulation pressure-controlled drilling, high-sand oil production, and natural gas hydrate drilling and production. There are still many deficiencies in the application process, mainly manifested as follows:

[0005] (1) Existing jet pumps, etc., after long-term suction and lifting of high-sand mixed slurry, will suffer from erosion, wear and blockage, which will seriously affect their working performance and reduce operating efficiency. In addition, they cannot divert the power fluid, and it is impossible to install power drilling tools, pressure-controlled jetting tools, etc. at the bottom.

[0006] (2) The existing turbine hydraulic lifting tools have a complex structure. Since the sand content of the mixed liquid is often high during the production process, it is very easy for the pump to get stuck and the pipeline to get blocked, which will consume a lot of manpower and material resources for shutdown and maintenance, causing significant economic losses.

[0007] (3) Existing electric-driven pumps such as disc pumps, multi-stage centrifugal pumps and plunger pumps require cable connections and need to be lowered to the seabed individually or attached to the operating pipe string, resulting in complex processes and heavy workload.

[0008] (4) The existing replaceable core jet pump has a complex structure, the core components are easily damaged, and the reliability is low.

[0009] Therefore, in order to meet the needs of concentric drill pipe reverse circulation controlled pressure drilling technology, concentric double-tube sand removal and oil production technology, double-layer tube natural gas hydrate drilling and production technology, etc., and at the same time solve the shortcomings of the above-mentioned existing downhole lifting pumps, it is urgent to invent a new type of reverse circulation bottom hole auxiliary drainage double-layer tube lifting tool, which can accurately control the downhole pressure and facilitate core replacement, increase the migration speed and fluidity of the annular return fluid, reduce the rock cuttings deposition in the pipeline, have a simple structure, and effectively prevent pump sticking and pipeline blockage, thereby improving production operation efficiency and safety. Summary of the invention

[0010] 1. Technical issues to be solved

[0011] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a double-layer pipe lifting tool for reverse circulation bottom hole drainage. The present invention adopts a self-locking slideway core replacement mechanism to achieve replaceable pump cores to solve the problems of pump core erosion and wear; it can be directly connected to the production pipe string and drilled with the pipe string to solve the problems of complex layout process and large workload of existing production lifting pumps; it adopts a jet lifting structure and a self-locking slideway structure to control the injection flow of the power fluid and replace the core replacement mechanism with different inner diameters to meet the needs of different degrees of suction and lifting of the return fluid and accurately control the downhole pressure; it adopts the principle of negative pressure absorption, and there are no moving components inside the downhole pipe string to solve the problem of easy pump jam and pipeline blockage, and reduce the loss of shutdown and maintenance; it adopts a self-locking slideway structure, the core replacement structure is simple, and the service life and reliability are improved.

[0012] (II) Technical solution

[0013] The objective of the present invention is achieved through the following technical solutions: a reverse circulation bottom-assisted double-layer pipe lifting tool, characterized in that it is composed of a locking rail mechanism, a core replacement mechanism and a diversion mechanism; wherein the locking rail mechanism is composed of an upper pipe column joint 1, an inner pipe 2, an upper inner pipe joint 4, a self-locking rail 5 and a self-locking joint 11, the self-locking joint 11 is provided with a boss Ⅰ1101, a boss Ⅱ1103, a boss Ⅲ1104 and a boss Ⅳ1107, the bottom end of the upper pipe column joint 1 is connected to the boss Ⅳ1107 of the self-locking joint 11 by a threaded connection, the bottom end of the inner pipe 2 is connected to the top of the upper inner pipe joint 4 by a threaded connection, and the upper The bottom end of the inner pipe joint 4 and the self-locking track 5 are both connected to the boss Ⅰ1101 of the self-locking joint 11 through threads; the core replacement mechanism is composed of a return liquid boosting pipe 3, a self-locking nut 6, a self-locking convex head spring 7, a self-locking convex head 8, a nozzle boosting pipe connecting tube 9, a suction nozzle 10, a high-pressure water inlet cylinder 12, a rubber sealing ring 14 and a diverter nozzle 15. The return liquid boosting pipe 3 is provided with a diffusion pipe 301, a self-locking convex head mounting hole 302 and a throat 303. The bottom end of the return liquid boosting pipe 3 is connected to the top of the nozzle boosting pipe connecting tube 9 through threads, and the self-locking nut 6 is connected to the self-locking convex head mounting hole 302 of the return liquid boosting pipe 3. Through threaded connection, the self-locking convex head 8 is connected to the self-locking nut 6 through the self-locking convex head spring 7. The self-locking convex head 8 is always in contact with the self-locking track 5 under the thrust of the self-locking convex head spring 7. The bottom end of the nozzle booster pipe connecting tube 9 is connected to the top end of the suction nozzle 10 through a threaded connection. The bottom end of the suction nozzle 10 and the top end of the diverter nozzle 15 are respectively connected to the top and bottom ends of the high-pressure water inlet cylinder 12 through a threaded connection. A plurality of rubber sealing rings 14 are installed on the sealing ring groove 12-1 of the high-pressure water inlet cylinder 12; the diverter mechanism is composed of an inner pipe joint 13, a thrust bearing 16, a spring sand prevention cylinder 17, a reverse thrust spring 18, and a spring mounting cylinder 1 9 and a lower pipe column joint 20, the inner pipe joint 13 is provided with a boss V 1301 and a boss VI 1303, the boss V 1301 of the inner pipe joint 13 is connected with the boss II 1103 of the self-locking joint 11 by threads, the top of the lower pipe column joint 20 is connected with the boss III 1104 of the self-locking joint 11 by threads, the boss VI 1303 of the inner pipe joint 13 is connected with the top of the spring mounting tube 19 by threads, the spring sand prevention tube 17 is fixed at the top of the thrust bearing 16, the spring sand prevention tube 17 can do circumferential movement, and the bottom end of the thrust bearing 16 is connected with the bottom end of the spring mounting tube 19 by a reverse thrust spring 18.

[0014] The reverse circulation bottom-hole drainage double-layer pipe lifting tool is characterized in that: the inner pipe 2 is provided with support blocks 201 evenly distributed circumferentially, and is fixedly connected to the upper pipe column joint 1 by welding.

[0015] The reverse circulation bottom-hole drainage double-layer pipe lifting tool is characterized in that: the self-locking track 5 is provided with a self-locking convex head inclined surface 501, a rising inclined surface 502, a core replacement lowering platform 503, an old core upper moving platform 504, a suction platform 505, an increasing inclined surface 506 and a guide platform 507 distributed in a stepped manner, and the self-locking convex head 8 can move along the guide surface of the self-locking track 5, thereby completing the self-locking and unlocking of the core replacement mechanism.

[0016] The reverse circulation bottom-hole drainage double-layer pipe lifting tool is characterized in that: the self-locking joint 11 is provided with keyway-type boosting holes 1102 evenly distributed circumferentially for the circulation of high-pressure power fluid; it is provided with suction holes 1105 evenly distributed circumferentially for the circulation of mixed slurry; it is provided with a pump core hole 1106 for the installation of a core replacement mechanism.

[0017] The reverse circulation bottom-hole drainage double-layer pipe lifting tool is characterized in that the inner pipe joint 13 is provided with a diversion hole Ⅰ1302 for the circulation of power fluid.

[0018] The reverse circulation bottom-hole drainage double-layer pipe lifting tool is characterized in that the nozzle booster pipe connecting tube 9 is provided with rectangular holes 9-1 evenly distributed in the circumferential direction for the circulation of mixed slurry.

[0019] The reverse circulation bottom-hole drainage double-layer pipe lifting tool is characterized in that the high-pressure water inlet cylinder 12 is provided with circumferentially evenly distributed diversion holes II 12-2 for the circulation of power fluid.

[0020] The reverse circulation bottom-hole drainage double-layer pipe lifting tool is characterized in that a thin-walled tube 1701 is provided in the middle of the spring sand prevention tube 17 to prevent sand and gravel from depositing and clogging the reverse thrust spring 18.

[0021] The reverse circulation bottom-hole drainage double-layer pipe lifting tool is characterized in that the upper pipe column joint 1 and the top end of the inner pipe 2 are both provided with threads for connecting the upper pipe column.

[0022] The reverse circulation bottom-hole drainage double-layer pipe lifting tool is characterized in that the bottom end of the lower pipe column joint 20 is provided with a thread for connecting the lower pipe column.

[0023] A suction and lifting method for a reverse circulation bottom-hole drainage double-layer pipe lifting tool, characterized in that: when performing production operations, its working procedures can be divided into a power fluid input process, a power fluid downward movement process, a power fluid diversion process and a mixed slurry suction and lifting process, and the steps are as follows:

[0024] S1. Power fluid input process: The tool is connected to the downhole device assembly. The frequency conversion control cabinet on the ground controls the speed of the ground pump and the power fluid flow rate, which can adjust the mixed slurry suction and lifting speed, and then control the return fluid production. After the power fluid is pressurized by the ground pump, it passes through the upper pipe string of the tool to reach the annulus between the upper pipe string joint 1 and the inner pipe 2;

[0025] S2, the process of power fluid moving downward: the high-pressure power fluid enters the annulus between the upper pipe joint 1 and the inner pipe 2 through the pressure-increasing hole 1102 of the self-locking joint 11 and enters the annulus between the inner pipe joint 13 and the lower pipe joint 20, and then passes through the diverter hole I 1302 of the inner pipe joint 13 and the diverter hole II 12-2 of the high-pressure water inlet cylinder 12 in sequence, and reaches the high-pressure water inlet cylinder 12;

[0026] S3, power fluid diversion process: high-pressure power fluid is diverted in the high-pressure water inlet cylinder 12, a part of the power fluid enters the diversion nozzle 15 downward, and enters the lower pipe column through the spring sand prevention cylinder 17, the spring installation cylinder 19 and the lower pipe column joint 20 in sequence; the other part of the power fluid moves upward and enters the suction nozzle 10;

[0027] S4. Mixed slurry suction and lifting process: The power fluid sprayed by the suction nozzle 10 will generate negative pressure adsorption between the suction nozzle 10 and the return liquid booster pipe 3. The mixed slurry is sucked into the return liquid booster pipe 3 through the suction hole 1105 of the self-locking joint 11 and the rectangular hole 9-1 of the nozzle booster pipe connecting tube 9 in turn. The power fluid is mixed with the mixed slurry to form the return liquid and enters the inner pipe 2 after being decelerated and pressurized. The return liquid enters the upper tubing string of the tool and is transported through the tubing string to the ground for sand removal, oil-gas-liquid separation and purification. The cycle is repeated to achieve high-efficiency production operations.

[0028] A core replacement method for a reverse circulation bottom-assisted drainage double-layer pipe lifting tool, characterized in that: when performing a core replacement operation, its working procedure can be divided into a power fluid pumping process, an old core unlocking process, an old core returning process and a core replacement self-locking process, and the steps are as follows:

[0029] S1, power fluid pumping process: after the power fluid is pressurized by the ground pump, it passes through the upper pipe string of the tool and reaches the inner pipe 2;

[0030] S2, the process of unlocking the old core: the high-pressure power fluid exerts pressure on the return fluid boosting pipe 3, and the return fluid boosting pipe 3 moves downward under the action of the pressure, driving the self-locking protrusion 8 to move downward, and the position of the self-locking protrusion 8 moves from the suction platform 505 of the self-locking track 5 to the old core upper moving platform 504, the reverse thrust spring 18 is compressed, and the injection of power fluid into the inner tube 2 is stopped. The core replacement mechanism moves upward under the reset thrust of the reverse thrust spring 18, and the self-locking protrusion 8 moves to the guide platform 507 through the increased inclined surface 506 of the self-locking track 5, completing the unlocking of the core replacement mechanism;

[0031] S3, old core return process: change the power fluid pumping direction, inject power fluid into the annulus between the upper pipe string joint 1 and the inner pipe 2, the core replacement mechanism moves upward under the action of the power fluid, and is taken out through the pipe string to the receiving device on the ground;

[0032] S4, core replacement self-locking process: change the power fluid pumping direction, inject power fluid into the inner tube 2, and the new core replacement mechanism enters the pipe string from the issuing device on the ground. As the power fluid enters the pump core hole 1106 of the self-locking joint 11, the self-locking protrusion 8 extends under the driving force of the self-locking protrusion spring 7, and passes through the self-locking protrusion inclined surface 501, the guide platform 507, and the rising inclined surface 502 of the self-locking track 5 in sequence to reach the core replacement lowering platform 503. The self-locking protrusion 8 is always in contact with the self-locking track 5 under the thrust of the self-locking protrusion spring 7. At the same time, the lower diverter nozzle 15 is in contact with the spring sand prevention cylinder 17 and squeezes the reverse thrust spring 18. After stopping the injection of power fluid, the core replacement mechanism moves upward under the thrust of the reverse thrust spring 18, and the self-locking protrusion 8 moves to the suction platform 505 of the self-locking track 5 to complete the core replacement operation.

[0033] (III) Beneficial effects

[0034] The beneficial effects of the present invention are:

[0035] (1) It can lift and drain the mixed slurry with high sand content and large-sized cuttings in the well;

[0036] (2) The pump core can be easily replaced without stopping for maintenance, thus improving production efficiency;

[0037] (3) It can be directly connected to the production string and lowered with the string, with simple layout process and small workload;

[0038] (4) By controlling the injection flow of the power fluid and replacing the core replacement mechanism with different inner diameters, different degrees of suction and lifting of the return fluid can be achieved, and the downhole pressure can be accurately controlled with high safety;

[0039] (5) The annular return fluid has high fluidity, the rock debris deposition in the pipeline is low and there are no moving components inside, which effectively prevents pump jams and pipeline blockages;

[0040] (6) It has a wide range of applications and is suitable for reverse circulation pressure-controlled drilling, high-sand oil production, natural gas hydrate drilling and other drainage operations;

[0041] (7) The core component of the core replacement adopts a self-locking slide structure, which has a simple structure and high reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 A cross-sectional view of the overall structure of the present invention;

[0043] Figure 2 It is a schematic diagram of the three-dimensional cross-sectional structure of the core replacement mechanism of the present invention;

[0044] Figure 3 This is a schematic cross-sectional view of the structure of the return liquid boosting pipe of the present invention;

[0045] Figure 4 This is a schematic diagram of the self-locking track structure of the present invention;

[0046] Figure 5 It is a top view schematic diagram of the upper pipe column joint and the inner pipe structure of the present invention;

[0047] Figure 6 It is a schematic diagram of the cross-sectional structure of the self-locking joint of the present invention;

[0048] Figure 7 It is a schematic diagram of the cross-sectional structure of the inner pipe joint of the present invention;

[0049] Figure 8 This is a schematic diagram of the structure of the spring sand prevention tube of the present invention;

[0050] Fig. 9 This is a schematic diagram of the core replacement process of the present invention;

[0051] Fig.10 A flow chart of a core replacement method for a reverse circulation bottom-hole drainage double-layer pipe lifting tool provided by the present invention;

[0052] Fig.11 A flow chart of a suction and lifting method of a reverse circulation bottom-hole drainage double-layer pipe lifting tool provided by the present invention;

[0053] 1. Upper pipe column joint; 2. Inner pipe; 3. Return liquid booster pipe; 4. Upper inner pipe joint; 5. Self-locking track; 6. Self-locking nut; 7. Self-locking convex spring; 8. Self-locking convex; 9. Nozzle booster pipe connecting tube; 10. Suction nozzle; 11. Self-locking joint; 12. High-pressure water inlet cylinder; 13. Inner pipe joint; 14. Rubber sealing ring; 15. Diverter nozzle; 16. Thrust bearing; 17. Spring sand prevention cylinder; 18. Thrust spring; 19. Spring installation cylinder; 20. Lower pipe column joint; 9-1. Rectangular hole; 12-1. Sealing ring groove; 12-2. Diverter hole II; 201. Support block; 301, diffuser; 302, self-locking boss mounting hole; 303, throat; 501, self-locking boss inclined surface; 502, rising inclined surface; 503, replacement core lowering platform; 504, old core upper platform; 505, suction platform; 506, heightening inclined surface; 507, guide platform; 1101, boss I; 1102, boosting hole; 1103, boss II; 1104, boss III; 1105, suction hole; 1106, pump core hole; 1107, boss IV; 1301, boss V; 1302, diverter hole I; 1303, boss VI; 1701, thin-walled cylinder. DETAILED DESCRIPTION

[0054] The technical solution of the present invention is described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0055] In the description of the present invention, it should be noted that the directions or positional relationships indicated by "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc. are directions or positional relationships based on the drawings, which are only for the convenience of describing the present invention 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 cannot be understood as limiting the present invention. In addition, "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0056] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0057] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0058] Embodiment 1

[0059] The reverse circulation bottom-hole drainage double-layer pipe lifting tool described in this embodiment is used in a vertical well section.

[0060] As shown in the figure, a reverse circulation well bottom drainage double-layer pipe lifting tool is composed of a locking rail mechanism, a core replacement mechanism and a diversion mechanism; wherein the locking rail mechanism is composed of an upper pipe column joint 1, an inner pipe 2, an upper inner pipe joint 4, a self-locking rail 5 and a self-locking joint 11, and the self-locking joint 11 is provided with a boss Ⅰ1101, a boss Ⅱ1103, a boss Ⅲ1104 and a boss Ⅳ1107, the bottom end of the upper pipe column joint 1 is connected to the boss Ⅳ1107 of the self-locking joint 11 by a thread, the bottom end of the inner pipe 2 is connected to the top of the upper inner pipe joint 4 by a thread, and the bottom end of the upper inner pipe joint 4 and the self-locking rail 5 are connected to the self-locking joint 11 by a thread. The boss Ⅰ1101 of the locking joint 11 is connected by threads; the core replacement mechanism is composed of a return liquid boosting pipe 3, a self-locking nut 6, a self-locking convex head spring 7, a self-locking convex head 8, a nozzle boosting pipe connecting tube 9, a suction nozzle 10, a high-pressure water inlet cylinder 12, a rubber sealing ring 14 and a diverter nozzle 15. The return liquid boosting pipe 3 is provided with a diffusion pipe 301, a self-locking convex head mounting hole 302 and a throat 303. The bottom end of the return liquid boosting pipe 3 is connected to the top of the nozzle boosting pipe connecting tube 9 by threads, the self-locking nut 6 is connected to the self-locking convex head mounting hole 302 of the return liquid boosting pipe 3 by threads, and the self-locking convex head is connected to the self-locking convex head mounting hole 302 of the return liquid boosting pipe 3 by threads. The head 8 is connected to the self-locking nut 6 through the self-locking convex head spring 7. The self-locking convex head 8 is always in contact with the self-locking track 5 under the thrust of the self-locking convex head spring 7. The bottom end of the nozzle booster pipe connecting tube 9 is connected to the top end of the suction nozzle 10 through a thread. The bottom end of the suction nozzle 10 and the top end of the diverter nozzle 15 are respectively connected to the top and bottom ends of the high-pressure water inlet cylinder 12 through a thread. A plurality of rubber sealing rings 14 are installed on the sealing ring groove 12-1 of the high-pressure water inlet cylinder 12; the diverter mechanism is composed of an inner pipe joint 13, a thrust bearing 16, a spring sand prevention cylinder 17, a reverse thrust spring 18, a spring mounting cylinder 19 and a lower pipe column. The inner pipe joint 13 is composed of a boss V 1301 and a boss VI 1303. The boss V 1301 of the inner pipe joint 13 is connected to the boss II 1103 of the self-locking joint 11 by threads. The top of the lower pipe column joint 20 is connected to the boss III 1104 of the self-locking joint 11 by threads. The boss VI 1303 of the inner pipe joint 13 is connected to the top of the spring mounting tube 19 by threads. The spring sand prevention tube 17 is fixed to the top of the thrust bearing 16. The spring sand prevention tube 17 can move circumferentially. The bottom end of the thrust bearing 16 is connected to the bottom end of the spring mounting tube 19 by a reverse thrust spring 18.

[0061] The reverse circulation bottom-hole drainage double-layer pipe lifting tool is characterized in that: the inner pipe 2 is provided with support blocks 201 evenly distributed circumferentially, and is fixedly connected to the upper pipe column joint 1 by welding.

[0062] The reverse circulation bottom-hole drainage double-layer pipe lifting tool is characterized in that: the self-locking track 5 is provided with a self-locking convex head inclined surface 501, a rising inclined surface 502, a core replacement lowering platform 503, an old core upper moving platform 504, a suction platform 505, an increasing inclined surface 506 and a guide platform 507 distributed in a stepped manner, and the self-locking convex head 8 can move along the guide surface of the self-locking track 5, thereby completing the self-locking and unlocking of the core replacement mechanism.

[0063] The reverse circulation bottom-hole drainage double-layer pipe lifting tool is characterized in that: the self-locking joint 11 is provided with keyway-type boosting holes 1102 evenly distributed circumferentially for the circulation of high-pressure power fluid; it is provided with suction holes 1105 evenly distributed circumferentially for the circulation of mixed slurry; it is provided with a pump core hole 1106 for the installation of a core replacement mechanism.

[0064] The reverse circulation bottom-hole drainage double-layer pipe lifting tool is characterized in that the inner pipe joint 13 is provided with a diversion hole Ⅰ1302 for the circulation of power fluid.

[0065] The reverse circulation bottom-hole drainage double-layer pipe lifting tool is characterized in that the nozzle booster pipe connecting tube 9 is provided with rectangular holes 9-1 evenly distributed in the circumferential direction for the circulation of mixed slurry.

[0066] The reverse circulation bottom-hole drainage double-layer pipe lifting tool is characterized in that the high-pressure water inlet cylinder 12 is provided with circumferentially evenly distributed diversion holes II 12-2 for the circulation of power fluid.

[0067] The reverse circulation bottom-hole drainage double-layer pipe lifting tool is characterized in that a thin-walled tube 1701 is provided in the middle of the spring sand prevention tube 17 to prevent sand and gravel from depositing and clogging the reverse thrust spring 18.

[0068] The reverse circulation bottom-hole drainage double-layer pipe lifting tool is characterized in that the upper pipe column joint 1 and the top end of the inner pipe 2 are both provided with threads for connecting the upper pipe column.

[0069] The reverse circulation bottom-hole drainage double-layer pipe lifting tool is characterized in that the bottom end of the lower pipe column joint 20 is provided with a thread for connecting the lower pipe column.

[0070] The working process of the present invention for pumping and lifting the mixed slurry is as follows: when used for concentric drill pipe reverse circulation controlled pressure drilling and concentric double-tube sand removal and oil production, the tool is connected to the downhole device combination of the drilling and completion system. The frequency conversion control cabinet on the ground controls the speed of the ground pump and the flow rate of the power fluid to adjust the suction and lifting speed of the mixed slurry, thereby controlling the output of the return fluid. After the power fluid is pressurized by the ground pump, it passes through the upper tubular column of the tool to reach the annulus between the upper tubular column joint 1 and the inner pipe 2. The high-pressure power fluid enters the annulus between the inner pipe joint 13 and the lower tubular column joint 20 through the pressurization hole 1102 of the self-locking joint 11 from the annulus between the upper tubular column joint 1 and the inner pipe 2, and then passes through the diversion hole Ⅰ1302 of the inner pipe joint 13 and the diversion hole Ⅱ12-2 of the high-pressure water inlet cylinder 12 in turn to reach the high-pressure water inlet cylinder 12. The power fluid is diverted in the high-pressure water inlet cylinder 12, and a part of the power fluid flows downward. The power fluid flows into the diversion nozzle 15, and then passes through the spring sand prevention tube 17, the spring installation tube 19 and the lower pipe joint 20 to enter the lower pipe. The other part of the power fluid moves upward to enter the suction nozzle 10. The power fluid sprayed by the suction nozzle 10 will generate a negative pressure adsorption effect between the suction nozzle 10 and the return liquid booster pipe 3. The mixed slurry is sucked into the return liquid booster pipe 3 through the suction hole 1105 of the self-locking joint 11 and the rectangular hole 9-1 of the nozzle booster pipe connecting tube 9 in turn. The power fluid is mixed with the mixed slurry to form the return liquid and enters the inner pipe 2 after being decelerated and pressurized. The return liquid enters the upper pipe of the tool, moves through the pipe to the ground, removes sand, separates oil and gas, and purifies it. The cycle is repeated to achieve high-efficiency production operations. At the same time, we can control the mixed slurry suction and lifting speed by controlling the power fluid injection flow and replacing the core replacement mechanism with different inner diameters, and finely control the downhole pressure.

[0071] The core changing process of the present invention is as follows: after the power fluid is pressurized by the ground pump, it reaches the inner tube 2 through the upper pipe string of the tool, and the high-pressure power fluid exerts pressure on the return fluid boosting pipe 3. The return fluid boosting pipe 3 moves downward under the action of the pressure, driving the self-locking protrusion 8 to move downward, and the position of the self-locking protrusion 8 moves from the suction platform 505 of the self-locking track 5 to the old core upper moving platform 504, the reverse thrust spring 18 is compressed, and the injection of power fluid into the inner tube 2 is stopped. The core replacement mechanism moves upward under the reset thrust of the reverse thrust spring 18, and the self-locking protrusion 8 moves to the guide platform 507 through the increased inclined surface 506 of the self-locking track 5, completing the unlocking of the core replacement mechanism, changing the power fluid pumping direction, and injecting power fluid into the annulus between the upper pipe string joint 1 and the inner tube 2. The core replacement mechanism moves upward under the action of the power fluid and reaches the ground through the pipe string. The receiving device on the surface is taken out, the power fluid pumping direction is changed, and power fluid is injected into the inner tube 2. The new core replacement mechanism enters the pipe string from the issuing device on the ground. As the power fluid enters the pump core hole 1106 of the self-locking joint 11, the self-locking protrusion 8 extends out under the driving force of the self-locking protrusion spring 7, and passes through the self-locking protrusion inclined surface 501, the guide platform 507, and the rising inclined surface 502 of the self-locking track 5 in turn, and reaches the core replacement lowering platform 503. The self-locking protrusion 8 is always in contact with the self-locking track 5 under the thrust of the self-locking protrusion spring 7. At the same time, the lower diversion nozzle 15 is in contact with the spring sand prevention cylinder 17 and squeezes the reverse thrust spring 18. After the injection of power fluid is stopped, the core replacement mechanism moves upward under the thrust of the reverse thrust spring 18, and the self-locking protrusion 8 moves to the suction platform 505 of the self-locking track 5 to complete the core replacement operation.

[0072] Embodiment 2

[0073] The reverse circulation bottom-hole drainage double-layer pipe lifting tool described in this embodiment is used in the horizontal section.

[0074] As shown in the figure, a reverse circulation well bottom drainage double-layer pipe lifting tool is composed of a locking rail mechanism, a core replacement mechanism and a diversion mechanism; wherein the locking rail mechanism is composed of an upper pipe column joint 1, an inner pipe 2, an upper inner pipe joint 4, a self-locking rail 5 and a self-locking joint 11, and the self-locking joint 11 is provided with a boss Ⅰ1101, a boss Ⅱ1103, a boss Ⅲ1104 and a boss Ⅳ1107, the bottom end of the upper pipe column joint 1 is connected to the boss Ⅳ1107 of the self-locking joint 11 by a thread, the bottom end of the inner pipe 2 is connected to the top of the upper inner pipe joint 4 by a thread, and the bottom end of the upper inner pipe joint 4 and the self-locking rail 5 are connected to the self-locking joint 11 by a thread. The boss Ⅰ1101 of the locking joint 11 is connected by threads; the core replacement mechanism is composed of a return liquid boosting pipe 3, a self-locking nut 6, a self-locking convex head spring 7, a self-locking convex head 8, a nozzle boosting pipe connecting tube 9, a suction nozzle 10, a high-pressure water inlet cylinder 12, a rubber sealing ring 14 and a diverter nozzle 15. The return liquid boosting pipe 3 is provided with a diffusion pipe 301, a self-locking convex head mounting hole 302 and a throat 303. The bottom end of the return liquid boosting pipe 3 is connected to the top of the nozzle boosting pipe connecting tube 9 by threads, the self-locking nut 6 is connected to the self-locking convex head mounting hole 302 of the return liquid boosting pipe 3 by threads, and the self-locking convex head is connected to the self-locking convex head mounting hole 302 of the return liquid boosting pipe 3 by threads. The head 8 is connected to the self-locking nut 6 through the self-locking convex head spring 7. The self-locking convex head 8 is always in contact with the self-locking track 5 under the thrust of the self-locking convex head spring 7. The bottom end of the nozzle booster pipe connecting tube 9 is connected to the top end of the suction nozzle 10 through a thread. The bottom end of the suction nozzle 10 and the top end of the diverter nozzle 15 are respectively connected to the top and bottom ends of the high-pressure water inlet cylinder 12 through a thread. A plurality of rubber sealing rings 14 are installed on the sealing ring groove 12-1 of the high-pressure water inlet cylinder 12; the diverter mechanism is composed of an inner pipe joint 13, a thrust bearing 16, a spring sand prevention cylinder 17, a reverse thrust spring 18, a spring mounting cylinder 19 and a lower pipe column. The inner pipe joint 13 is composed of a boss V 1301 and a boss VI 1303. The boss V 1301 of the inner pipe joint 13 is connected to the boss II 1103 of the self-locking joint 11 by threads. The top of the lower pipe column joint 20 is connected to the boss III 1104 of the self-locking joint 11 by threads. The boss VI 1303 of the inner pipe joint 13 is connected to the top of the spring mounting tube 19 by threads. The spring sand prevention tube 17 is fixed to the top of the thrust bearing 16. The spring sand prevention tube 17 can move circumferentially. The bottom end of the thrust bearing 16 is connected to the bottom end of the spring mounting tube 19 by a reverse thrust spring 18.

[0075] The reverse circulation bottom-hole drainage double-layer pipe lifting tool is characterized in that: the inner pipe 2 is provided with support blocks 201 evenly distributed circumferentially, and is fixedly connected to the upper pipe column joint 1 by welding.

[0076] The reverse circulation bottom-hole drainage double-layer pipe lifting tool is characterized in that: the self-locking track 5 is provided with a self-locking convex head inclined surface 501, a rising inclined surface 502, a core replacement lowering platform 503, an old core upper moving platform 504, a suction platform 505, an increasing inclined surface 506 and a guide platform 507 distributed in a stepped manner, and the self-locking convex head 8 can move along the guide surface of the self-locking track 5, thereby completing the self-locking and unlocking of the core replacement mechanism.

[0077] The reverse circulation bottom-hole drainage double-layer pipe lifting tool is characterized in that: the self-locking joint 11 is provided with keyway-type boosting holes 1102 evenly distributed circumferentially for the circulation of high-pressure power fluid; it is provided with suction holes 1105 evenly distributed circumferentially for the circulation of mixed slurry; it is provided with a pump core hole 1106 for the installation of a core replacement mechanism.

[0078] The reverse circulation bottom-hole drainage double-layer pipe lifting tool is characterized in that the inner pipe joint 13 is provided with a diversion hole Ⅰ1302 for the circulation of power fluid.

[0079] The reverse circulation bottom-hole drainage double-layer pipe lifting tool is characterized in that the nozzle booster pipe connecting tube 9 is provided with rectangular holes 9-1 evenly distributed in the circumferential direction for the circulation of mixed slurry.

[0080] The reverse circulation bottom-hole drainage double-layer pipe lifting tool is characterized in that the high-pressure water inlet cylinder 12 is provided with circumferentially evenly distributed diversion holes II 12-2 for the circulation of power fluid.

[0081] The reverse circulation bottom-hole drainage double-layer pipe lifting tool is characterized in that a thin-walled tube 1701 is provided in the middle of the spring sand prevention tube 17 to prevent sand and gravel from depositing and clogging the reverse thrust spring 18.

[0082] The reverse circulation bottom-hole drainage double-layer pipe lifting tool is characterized in that the upper pipe column joint 1 and the top end of the inner pipe 2 are both provided with threads for connecting the upper pipe column.

[0083] The reverse circulation bottom-hole drainage double-layer pipe lifting tool is characterized in that the bottom end of the lower pipe column joint 20 is provided with a thread for connecting the lower pipe column.

[0084] The working process of the present invention for pumping and lifting mixed slurry is as follows: when used for double-layer pipe natural gas hydrate drilling and production, a single or multiple tools are simultaneously connected to the downhole device combination of the horizontal well section, and the frequency conversion control cabinet on the ground controls the speed of the ground pump and the flow rate of the power fluid to adjust the mixed slurry suction and lifting speed, thereby controlling the return fluid production. After the power fluid is pressurized by the ground pump, it passes through the upper pipe string of the tool to reach the annulus between the upper pipe string joint 1 and the inner pipe 2. The high-pressure power fluid enters the annulus between the inner pipe joint 13 and the lower pipe joint 20 through the pressurization hole 1102 of the self-locking joint 11 from the annulus between the upper pipe string joint 1 and the inner pipe 2, and then passes through the diverter hole Ⅰ1302 of the inner pipe joint 13 and the diverter hole Ⅱ12-2 of the high-pressure water inlet cylinder 12 in turn, and reaches the high-pressure water inlet cylinder 12. The power fluid is split in the high-pressure water inlet cylinder 12. A part of the power fluid enters the split nozzle 15 downward, and enters the lower pipe string through the spring sand prevention cylinder 17, the spring installation cylinder 19 and the lower pipe string joint 20 in turn. The other part of the power fluid moves upward and enters the suction nozzle 10. The power fluid sprayed from the suction nozzle 10 will produce a negative pressure adsorption effect between the suction nozzle 10 and the return liquid booster pipe 3. The mixed slurry is sucked into the return liquid booster pipe 3 through the suction hole 1105 of the self-locking joint 11 and the rectangular hole 9-1 of the nozzle booster pipe connecting cylinder 9 in turn. The power fluid is mixed with the mixed slurry to form the return liquid and enters the inner pipe 2 after being decelerated and pressurized. The return liquid enters the upper pipe string of the tool and is transported to the mining platform at the sea level through the pipe string for deep processing, thereby realizing high-efficiency mining of the mixed slurry.

[0085] The core changing process of the present invention is as follows: after the power fluid is pressurized by the ground pump, it reaches the inner tube 2 through the upper pipe string of the tool, and the high-pressure power fluid exerts pressure on the return fluid boosting pipe 3. The return fluid boosting pipe 3 moves downward under the action of the pressure, driving the self-locking protrusion 8 to move downward, and the position of the self-locking protrusion 8 moves from the suction platform 505 of the self-locking track 5 to the old core upper moving platform 504, the reverse thrust spring 18 is compressed, and the injection of power fluid into the inner tube 2 is stopped. The core replacement mechanism moves upward under the reset thrust of the reverse thrust spring 18, and the self-locking protrusion 8 moves to the guide platform 507 through the increased inclined surface 506 of the self-locking track 5, completing the unlocking of the core replacement mechanism, changing the power fluid pumping direction, and injecting power fluid into the annulus between the upper pipe string joint 1 and the inner tube 2. The core replacement mechanism moves upward under the action of the power fluid and reaches the ground through the pipe string. The receiving device on the surface is taken out, the power fluid pumping direction is changed, and power fluid is injected into the inner tube 2. The new core replacement mechanism enters the pipe string from the issuing device on the ground. As the power fluid enters the pump core hole 1106 of the self-locking joint 11, the self-locking protrusion 8 extends out under the driving force of the self-locking protrusion spring 7, and passes through the self-locking protrusion inclined surface 501, the guide platform 507, and the rising inclined surface 502 of the self-locking track 5 in turn, and reaches the core replacement lowering platform 503. The self-locking protrusion 8 is always in contact with the self-locking track 5 under the thrust of the self-locking protrusion spring 7. At the same time, the lower diversion nozzle 15 is in contact with the spring sand prevention cylinder 17 and squeezes the reverse thrust spring 18. After the injection of power fluid is stopped, the core replacement mechanism moves upward under the thrust of the reverse thrust spring 18, and the self-locking protrusion 8 moves to the suction platform 505 of the self-locking track 5 to complete the core replacement operation.

[0086] Obviously, the above embodiments are merely examples for clear explanation, and are not intended to limit the implementation methods. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from them are still within the protection scope of the invention.

Claims

1. A double-layer pipe lifting tool for reverse circulation bottom drainage. Features The invention comprises a rail locking mechanism, a core replacement mechanism and a flow diversion mechanism; wherein the rail locking mechanism is composed of an upper pipe column joint (1), an inner pipe (2), an upper inner pipe joint (4), a self-locking rail (5) and a self-locking joint (11); the self-locking joint (11) is provided with a boss I (1101), a boss II (1103), a boss III (1104) and a boss IV (1107); the bottom end of the upper pipe column joint (1) is connected to the boss IV (1107) of the self-locking joint (11) by threading; the bottom end of the inner pipe (2) is connected to the top end of the upper inner pipe joint (4) by threading; the bottom end of the upper inner pipe joint (4) and the self-locking rail (5) are both connected to the boss I (1101) of the self-locking joint (11) by threading; The core mechanism is composed of a return liquid boosting pipe (3), a self-locking nut (6), a self-locking convex head spring (7), a self-locking convex head (8), a nozzle boosting pipe connecting tube (9), a suction nozzle (10), a high-pressure water inlet tube (12), a rubber sealing ring (14) and a diversion nozzle (15). The return liquid boosting pipe (3) is provided with a diffusion pipe (301), a self-locking convex head mounting hole (302) and a throat pipe (303). The bottom end of the return liquid boosting pipe (3) is connected to the top end of the nozzle boosting pipe connecting tube (9) through a thread, the self-locking nut (6) is connected to the self-locking convex head mounting hole (302) of the return liquid boosting pipe (3) through a thread, and the self-locking convex head (8) is connected to the self-locking nut (3) through the self-locking convex head spring (7). 6), the self-locking convex head (8) is always in contact with the self-locking track (5) under the thrust of the self-locking convex head spring (7), the bottom end of the nozzle booster pipe connecting tube (9) is connected to the top end of the suction nozzle (10) through a thread, the bottom end of the suction nozzle (10) is connected to the top end of the high-pressure water inlet cylinder (12) through a thread, the top end of the diverter nozzle (15) is connected to the bottom end of the high-pressure water inlet cylinder (12) through a thread, and a plurality of rubber sealing rings (14) are installed on the sealing ring groove (12-1) of the high-pressure water inlet cylinder (12); the diverter mechanism is composed of an inner pipe joint (13), a thrust bearing (16), a spring sand prevention cylinder (17), a reverse thrust spring (18), a spring installation cylinder (19) and a lower pipe column joint (20 ), the inner pipe joint (13) is provided with a boss V (1301) and a boss VI (1303), the boss V (1301) of the inner pipe joint (13) is connected to the boss II (1103) of the self-locking joint (11) by threading, the top of the lower pipe column joint (20) is connected to the boss III (1104) of the self-locking joint (11) by threading, the boss VI (1303) of the inner pipe joint (13) is connected to the top of the spring installation cylinder (19) by threading, the spring sand prevention cylinder (17) is fixed to the top of the thrust bearing (16), the spring sand prevention cylinder (17) can move circumferentially, and the bottom of the thrust bearing (16) is connected to the bottom of the spring installation cylinder (19) by a reverse thrust spring (18).

2. A double-layer pipe lifting tool for reverse circulation bottom drainage according to claim 1, Features: The inner tube (2) is provided with support blocks (201) evenly distributed in the circumferential direction, and the support blocks (201) are fixedly connected to the upper pipe column joint (1) by welding.

3. A double-layer pipe lifting tool for reverse circulation bottom drainage according to claim 1, Features: The self-locking track (5) is provided with a self-locking convex head inclined surface (501), an ascending inclined surface (502), a core replacement lowering platform (503), an old core upper moving platform (504), a suction platform (505), an increasing inclined surface (506) and a guide platform (507) which are distributed in a stepped manner. The self-locking convex head (8) can move along the guide surface of the self-locking track (5), thereby completing the self-locking and unlocking of the core replacement mechanism.

4. A double-layer pipe lifting tool for reverse circulation bottom drainage according to claim 1, Features: The self-locking joint (11) is provided with keyway-type boosting holes (1102) evenly distributed in the circumference for the circulation of high-pressure power fluid; it is provided with suction holes (1105) evenly distributed in the circumference for the circulation of mixed slurry; it is provided with a pump core hole (1106) for the installation of a core replacement mechanism.

5. A double-layer pipe lifting tool for reverse circulation bottom drainage according to claim 1, Features: The inner pipe joint (13) is provided with a diversion hole I (1302) for the circulation of power fluid.

6. A double-layer pipe lifting tool for reverse circulation bottom drainage according to claim 1, Features: The nozzle booster pipe connecting tube (9) is provided with rectangular holes (9-1) evenly distributed in the circumferential direction for the circulation of the mixed slurry.

7. A double-layer pipe lifting tool for reverse circulation bottom drainage according to claim 1, Features: The high-pressure water inlet cylinder (12) is provided with circumferentially evenly distributed diversion holes II (12-2) for the circulation of power fluid.

8. A double-layer pipe lifting tool for reverse circulation bottom drainage according to claim 1, Features: The spring sand prevention cylinder (17) is provided with a thin-walled cylinder (1701) in the middle, which can prevent sand and gravel from being deposited and blocking the reverse thrust spring (18).

9. A suction lifting method for a double-layer pipe lifting tool for reverse circulation bottom drainage. Features: When carrying out production operations, the working procedures can be divided into the power fluid input process, the power fluid downward movement process, the power fluid diversion process and the mixed slurry suction and lifting process. The steps are as follows: S1, power fluid input process: the tool is connected to the downhole device assembly, and the frequency conversion control cabinet on the ground controls the power fluid flow by controlling the rotation speed of the ground pump, thereby adjusting the mixed slurry suction and lifting speed, thereby controlling the return fluid production. After the power fluid is pressurized by the ground pump, it passes through the upper pipe string of the tool to reach the annulus between the upper pipe string joint (1) and the inner pipe (2), and the upper pipe string joint (1) and the inner pipe (2) are fixedly connected by welding with a support block (201); S2, the process of the power fluid moving downward: the high-pressure power fluid enters the annular space between the upper pipe column joint (1) and the inner pipe (2) through the pressure-increasing hole (1102) of the self-locking joint (11) and enters the annular space between the inner pipe joint (13) and the lower pipe column joint (20), and then passes through the diverter hole I (1302) of the inner pipe joint (13) and the diverter hole II (12-2) of the high-pressure water inlet cylinder (12) in sequence, and reaches the high-pressure water inlet cylinder (12); S3, power fluid diversion process: the bottom end of the high-pressure water inlet cylinder (12) is connected to the top end of the diversion nozzle (15) by threaded connection, the top end of the high-pressure water inlet cylinder (12) is connected to the top end of the suction nozzle (10) by threaded connection, the top end of the spring mounting cylinder (19) is connected to the inner pipe joint (13) by boss VI (1303), the spring sand prevention cylinder (17) is fixed to the top end of the thrust bearing (16), and the high-pressure power fluid is diverted in the high-pressure water inlet cylinder (12), a part of the power fluid flows downward into the diversion nozzle (15), and then passes through the spring sand prevention cylinder (17), the spring mounting cylinder (19) and the lower pipe column joint (20) to enter the lower pipe column; the other part of the power fluid moves upward into the suction nozzle (10); S4, mixed slurry suction and lifting process: the power fluid sprayed by the suction nozzle (10) will generate a negative pressure adsorption effect between the suction nozzle (10) and the return liquid booster pipe (3), and the mixed slurry is sucked into the return liquid booster pipe (3) through the suction hole (1105) of the self-locking joint (11) and the rectangular hole (9-1) of the nozzle booster pipe connecting tube (9) in turn, and the power fluid is mixed with the mixed slurry to form the return liquid, which is decelerated and pressurized and then enters the inner pipe (2), and the return liquid enters the upper pipe string of the tool, and is transported through the pipe string to the ground for sand removal, oil, gas and liquid separation and purification, and the cycle is repeated to achieve high-efficiency production operations.

10. A core replacement method for a double-layer pipe lifting tool for reverse circulation bottom drainage. Features: When performing a core replacement operation, the working procedure can be divided into the process of pumping in the power fluid, unlocking the old core, returning the old core, and self-locking the replacement core. The steps are as follows: S1, power fluid pumping process: after the power fluid is pressurized by the surface pump, it passes through the upper pipe string of the tool and reaches the inner pipe (2); S2, the process of unlocking the old core: the bottom end of the return liquid boosting pipe (3) is connected to the top end of the nozzle boosting pipe connecting tube (9) by a threaded connection, the self-locking convex head (8) is connected to the self-locking nut (6) by the self-locking convex head spring (7), and the high-pressure power fluid exerts pressure on the return liquid boosting pipe (3). The return liquid boosting pipe (3) moves downward under the action of the pressure, driving the self-locking convex head (8) to move downward. The position of the self-locking convex head (8) moves from the suction platform (505) of the self-locking track (5) to the old core upper moving platform (504), the reverse thrust spring (18) is compressed, and the injection of power fluid into the inner tube (2) is stopped. The core replacement mechanism moves upward under the reset thrust of the reverse thrust spring (18), and the self-locking convex head (8) moves to the guide platform (507) through the increased inclined surface (506) of the self-locking track (5), completing the unlocking of the core replacement mechanism; S3, the old core return process: the power fluid pumping direction is changed, and the power fluid is injected into the annulus between the upper pipe column joint (1) and the inner pipe (2). The core replacement mechanism moves upward under the action of the power fluid and is taken out through the pipe column to the receiving device on the ground; S4, core replacement self-locking process: the power fluid pumping direction is changed, and the power fluid is injected into the inner tube (2). The new core replacement mechanism enters the pipe column from the sending device on the ground. As the power fluid enters the pump core hole (1106) of the self-locking joint (11), the self-locking convex head (8) extends under the driving force of the self-locking convex head spring (7), and passes through the self-locking convex head inclined surface (501), the guide platform (507), and the rising inclined surface (502) of the self-locking track (5) in sequence, and reaches The core replacement platform (503) moves downward, and the self-locking convex head (8) is always in contact with the self-locking track (5) under the thrust of the self-locking convex head spring (7). At the same time, the lower diversion nozzle (15) contacts the spring sand prevention cylinder (17) and squeezes the reverse thrust spring (18). After the injection of power fluid stops, the core replacement mechanism moves upward under the thrust of the reverse thrust spring (18), and the self-locking convex head (8) moves to the suction platform (505) of the self-locking track (5), completing the core replacement operation.

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