A multi-time pressure testing mechanical slide rail type toe end sliding sleeve

Abstract

The present application relates to the field of oil and gas well downhole operation, disclose a kind of multiple pressure test mechanical slide rail type toe end sliding sleeve, including static locking mechanism is located in outer sleeve, the center guide cylinder of cooperation outer sleeve is used to form static reverse push test switching structure;Pressure test counting mechanism is located in static locking mechanism, cooperation static casing, embedded static cylinder, unlocking guide groove and reset snap spring two for forming rotatable multiple test switching structure;Sealing push mechanism is located in outer sleeve, cooperation center guide cylinder of outer sleeve and static casing is used to constitute pressure receiving structure when pressure test and work;Synchronous switching mechanism is located in outer sleeve, cooperation push ring, rotating sleeve, trapezoidal guide strip, linkage tooth edge cylinder Tapered tooth key and anti-rotation guide strip is used to form multiple pressure test limit switching structure. Through pressure conversion, multiple pressure test and final fracturing opening are completed, which greatly reduces the fault risk of downhole operation.

Description

Technical Field

[0001] This invention relates to the field of downhole operations technology for oil and gas wells, specifically to a mechanical sliding rail type toe sleeve that undergoes multiple pressure tests. Background Technology

[0002] In horizontal well fracturing and completion operations, the toe sleeve is a key downhole tool installed at the very end (toe) of the completion string. Its main function is to open it by pressurizing the surface into the string after the string has been run in and cemented, thereby establishing an initial fluid circulation channel between the inside of the string and the external formation, providing conditions for subsequent first-stage fracturing or perforation operations.

[0003] In actual oil and gas field operations, to ensure the sealing integrity of the entire completion string and cementing sheath, a high-pressure sealing test is usually required before fracturing operations. Because the opening mechanism is a single, irreversible pressure trigger, the pressure during the test must be strictly lower than the opening pressure of the sliding sleeve. This limits the test pressure and makes it impossible to truly verify the sealing reliability of the wellbore under actual high-pressure fracturing conditions. If the pressure is increased to meet the test standards, it is very easy to cause the shear pin or fracture plate to fail prematurely, resulting in the toe sliding sleeve being accidentally triggered and opened prematurely, causing the subsequent pressure test to fail completely. Faced with the alternating load impact of multiple pressurization and depressurization, traditional shear pins will experience severe metal fatigue accumulation. Even if the single pressurization does not reach the rated opening pressure, repeated pressure tests are very likely to cause the pin to fatigue and break, thus causing the sliding sleeve to open prematurely.

[0004] Although some toe sleeves using electronic timing or electronic pressure counting have appeared on the market, the downhole environment is under extreme high temperature, high pressure and strong vibration. The reliability and lifespan of electronic components, sensors and batteries are difficult to guarantee. They are prone to dormancy or failure of electronic components, which will eventually prevent the sleeve from opening. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a mechanical sliding rail type toe sleeve that can withstand multiple pressure tests. This solves the problem that existing toe sleeves, whether mechanical or electronic, are prone to fatigue and accidental opening during repeated high-pressure tests, or electronic ones are prone to failure in extreme downhole environments. Neither of these solutions can simultaneously meet the requirements of repeated high-pressure sealing tests and the reliability of downhole operations.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a mechanical slide rail type toe end sleeve subjected to multiple pressure tests, comprising: External sleeve, used in the combination of toe-end sliding sleeve structure; The end sleeve is located on the outer sleeve and is used to form the input end portion of the toe sleeve; The closed ring mechanism is located on the outer sleeve and works with the fracturing groove of the outer sleeve to form an openable and closable sleeve structure that can be closed and unblocked. The stationary locking mechanism is located on the outer sleeve and works with the central guide tube of the outer sleeve to form a stationary reverse push test switching structure; The pressure testing and counting mechanism is located in the stationary locking mechanism, and together with the stationary sleeve, the embedded stationary cylinder, the unlocking guide groove and the reset snap ring, it forms a rotatable multiple test switching structure. The sealing and pushing mechanism is located on the outer sleeve, and together with the central guide tube of the outer sleeve and the stationary sleeve, it forms a pressure receiving structure during pressure testing and operation. The synchronous switching mechanism is located on the external sleeve, and together with the push ring, rotating sleeve, trapezoidal guide strip, conical tooth key of the linkage toothed cylinder, and anti-rotation guide strip, it forms a limited number switching structure that can be tested multiple times.

[0007] Preferably, the central guide tube of the outer sleeve is fixed at the end of the outer sleeve and extends into the interior of the outer sleeve, while the fracturing slots are distributed circumferentially on the outer sleeve in a linear parallel manner. The end sleeve is engaged with the input end of the outer sleeve as a connection port of the external pressure transmission pipe. The closing ring mechanism is embedded in the interior of the outer sleeve and can contact the inner wall of the end sleeve. The stationary locking mechanism is located in the central sleeve of the outer sleeve and close to the end of the outer sleeve. The pressure test counting mechanism is located on the stationary locking mechanism. The sealing pushing mechanism is located at the port of the central guide tube of the outer sleeve and is embedded in the central guide tube. The synchronous switching mechanism is stationarily embedded in the central guide tube of the outer sleeve and is placed between the pressure test counting mechanism and the sealing pushing mechanism.

[0008] Preferably, the closed ring mechanism includes a closed sleeve, which is embedded in the outer sleeve, and its end is connected to the inner wall of the outer sleeve through a reset spring. The other end of the closed sleeve is fitted to the end of the end sleeve. The outer side of the closed sleeve is provided with circumferentially distributed closed material channels, which are parallel to and correspond to the fracturing slots of the outer sleeve. The push ring is fixed to the inner wall of the closed sleeve and is fitted to the central guide tube of the outer sleeve.

[0009] Preferably, the stationary locking mechanism includes a stationary sleeve, which is fixed to the inner wall of the central guide tube of the outer sleeve and close to the end of the outer sleeve. The embedded stationary tube is fixed inside the stationary sleeve. The unlocking guide groove is provided on the side of the stationary sleeve. The reset snap ring is provided on the side wall of the embedded stationary tube facing the pressure counting mechanism.

[0010] Preferably, the pressure testing counting mechanism includes a rotating sleeve that slides along the outer ring of the stationary sleeve, and the inner wall of the rotating sleeve abuts against the reset spring 2. The trapezoidal guide strip is disposed opposite to each other on both sides of the rotating sleeve, and the elastic force of the reset spring 2 can keep the trapezoidal guide strip in contact with the synchronous switching mechanism at all times.

[0011] Preferably, the sealing and pushing mechanism includes a piston inner cylinder, which slides along the inner wall of the closed ring sleeve mechanism, and the piston inner cylinder is simultaneously placed in contact with the pushing ring. The linkage toothed cylinder is fixed inside the piston inner cylinder and embedded in the central guide cylinder of the outer sleeve. The bottom end of the linkage toothed cylinder is provided with circumferentially distributed conical teeth.

[0012] Preferably, the synchronous switching mechanism includes a stationary toothed cylinder, which is fixed inside the central sleeve of the outer sleeve, and the internal part allows the linkage toothed cylinder to be embedded. The bottom edge of the stationary toothed cylinder is a trapezoidal guide groove that is circumferentially distributed and interlocking with each other, and the inclined surface of the trapezoidal guide groove corresponds to the inclined surface of the conical tooth key of the linkage toothed cylinder, and can also be in contact with the top inclined surface of the trapezoidal guide strip.

[0013] Preferably, the top contact strip is disposed on the inner wall of the rotating sleeve and can be embedded and slid into the unlocking guide groove.

[0014] Preferably, the piston inner cylinder has a fitting and embedding shaft fixed inside, which faces the inner stationary cylinder and can be embedded into the inner stationary cylinder, and the end of the fitting and embedding shaft is provided with a locking step block that can be elastically extended and retracted inside and outside.

[0015] Preferably, the stationary toothed cylinder has a corresponding anti-rotation groove inside, which is connected and wedges with the anti-rotation strip.

[0016] This invention provides a mechanical slide rail type toe end sleeve that undergoes multiple pressure tests. It has the following beneficial effects: 1. This invention relies on the pressurization and depressurization of external fluids to drive internal mechanical components. Through pressure conversion, multiple pressure tests and the final fracturing are completed, which greatly reduces the risk of failure in downhole operations. 2. In the pressure descent stage, the interlocking constraint between the anti-rotation guide strip and the anti-rotation guide groove plays a key role in restricting the rotation of the force-bearing components and ensuring the linear transmission of the downward thrust. At the same time, when the linear downward thrust contacts the bottom slope, it is precisely converted into a lateral sliding force, ensuring the smooth sliding of the internal structure. 3. The pressure test counting of this invention is entirely dependent on the pressure increase and decrease that occur during the operation. When pressure is increased, the rotating sleeve is pressed down and is rigidly blocked by the solid end face, while completing a partial angle deflection. When pressure is decreased, the reverse thrust of the reset spring drives the sleeve back and slides into the next station along the inclined surface of the guide groove, so that each pressure test can be converted into a count. Attached Figure Description

[0017] Figure 1 This is a perspective view of the main structure of the present invention; Figure 2 This is a schematic cross-sectional view of the structure of the present invention. Figure 1 ; Figure 3 This is a schematic diagram of the external sleeve structure assembly of the present invention; Figure 4 This is a schematic cross-sectional view of the structure of the present invention. Figure 2 ; Figure 5 This is a cross-sectional schematic diagram of the closed ring mechanism structure of the present invention; Figure 6 This is a cross-sectional schematic diagram of the external sleeve structure of the present invention; Figure 7 This is a schematic diagram of the combined structure of the stationary locking mechanism, the pressure testing and counting mechanism, and the sealing and pushing mechanism of the present invention; Figure 8 This is a cross-sectional schematic diagram of the sealing and pushing mechanism structure of the present invention; Figure 9 This is a schematic diagram of the sealing and pushing mechanism of the present invention in its installation state; Figure 10 This is a schematic diagram of the pressure testing structure of the present invention; Figure 11 This is a schematic diagram of the installation state of the pressure testing and counting mechanism of the present invention; Figure 12 This is a schematic diagram of the installation state of the synchronous switching mechanism structure of the present invention; Figure 13 This is a cross-sectional schematic diagram of the pressure testing structure assembly of the present invention.

[0018] Among them, 1. External sleeve; 2. End sleeve; 3. Closed ring mechanism; 4. Static locking mechanism; 5. Test pressure counting mechanism; 6. Sealing and pushing mechanism; 7. Synchronous switching mechanism; 31. Closed sleeve; 32. Closed material channel; 33. Reset snap ring one; 34. Push ring; 41. Static sleeve; 42. Inset static cylinder; 43. Unlocking guide groove; 44. Reset snap ring two; 51. Rotating sleeve; 52. Trapezoidal guide strip; 53. Top contact strip; 61. Piston inset cylinder; 62. Linkage toothed cylinder; 63. Anti-rotation guide strip; 64. Fitting embedded shaft; 65. Locking ladder block; 71. Static toothed cylinder; 72. Anti-rotation guide groove. Detailed Implementation

[0019] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] Please see the appendix Figure 1 - Appendix Figure 3 This invention provides a mechanical sliding rail type toe sleeve for multiple pressure tests, comprising: an outer sleeve 1 for assembling the toe sleeve structure; a central guide tube of the outer sleeve 1 fixed at the end of the outer sleeve 1 and extending into the interior of the outer sleeve 1; fracturing grooves distributed circumferentially on the outer sleeve 1 in a linear parallel arrangement; when external high-pressure fluid acts directly on the system, the outer sleeve 1 acts as the entire skeleton to bear and transmit the pushing force; and an end sleeve 2 located on the outer sleeve 1 to form the input end portion of the toe sleeve. The end sleeve 2 engages with the input end of the outer sleeve 1 and serves as the connection port of the external pressure transmission pipe. The end sleeve 2 serves as the initial force inlet for the entire system to receive external fluid pressure and directly receives the high-pressure fluid pumped in by the external pressure transmission pipe. Please see the appendix Figure 3 - Appendix Figure 5 The closing ring mechanism 3 is located in the outer sleeve 1 and works with the fracturing groove of the outer sleeve 1 to form an openable and closed sleeve structure that can be closed and unblocked. The closing ring mechanism 3 is embedded in the outer sleeve 1 and can contact the inner wall of the end sleeve 2. After receiving the downward pushing force inside the outer sleeve 1, the closing ring mechanism 3 overcomes the side friction resistance and slides downward in a straight line. Before the sliding action occurs, the pipe wall of the closing ring mechanism 3 tightly blocks the fracturing groove of the outer sleeve 1, cutting off the fluid leakage path. When the closing ring mechanism 3 is pushed down and travels to the specified depth, its own structure is misaligned with the external opening, so that the fracturing groove of the outer sleeve 1 is completely exposed, thereby opening up the internal and external space. Please see the appendix Figure 3 - Appendix Figure 5The closed-loop mechanism 3 includes a closed sleeve 31, which is embedded in the outer sleeve 1. Its end is connected to the inner wall of the outer sleeve 1 via a reset spring 33. The other end of the closed sleeve 31 is fitted to the end of the end sleeve 2. A circumferentially distributed closed material channel 32 is provided on the outer side of the closed sleeve 31, corresponding to the fracturing groove of the outer sleeve 1. A push ring 34 is fixed to the inner wall of the closed sleeve 31 and fitted to the central guide tube of the outer sleeve 1. When the upper moving component pushes downwards... When the push ring 34 is pressed, the push ring 34 directly transmits the downward thrust to the connected closed sleeve 31, forcing the closed sleeve 31 to slide downward. When the closed sleeve 31 slides downward, it simultaneously squeezes the reset spring 33, causing the reset spring 33 to elastically contract and accumulate rebound force. As the closed sleeve 31 continues to sink, the closed material channel 32 on its outer side moves downward until the closed material channel 32 is completely aligned with the fracturing groove hole of the outer sleeve 1 at the same horizontal plane, establishing a smooth discharge path for the high-pressure fluid to be ejected outward.

[0021] Please see the appendix Figure 4 - Appendix Figure 6 The stationary locking mechanism 4 is located in the outer sleeve 1 and works with the central guide tube of the outer sleeve 1 to form a stationary reverse push test switching structure. The stationary locking mechanism 4 is set inside the central sleeve of the outer sleeve 1 and close to the end of the outer sleeve 1. The stationary locking mechanism 4 acts as a stable support and reverse push base inside the central guide tube of the outer sleeve 1. Please see the appendix Figure 9 - Appendix Figure 10 The stationary locking mechanism 4 includes a stationary sleeve 41, which is fixed to the inner wall of the central guide tube of the outer sleeve 1 and close to the end of the outer sleeve 1. An inner stationary tube 42 is fixed inside the stationary sleeve 41. An unlocking guide groove 43 is provided on the side of the stationary sleeve 41. A reset spring 44 is provided on the side wall of the inner stationary tube 42 facing the pressure counting mechanism 5. When pressed down by the upper component, the stationary sleeve 41 acts as a sliding track to guide the upper structure to slide smoothly downward. At the same time, the downward pressure forces the reset spring 44 to contract and generate an upward reverse elastic force. When the protrusion of the upper component is not aligned with the unlocking guide groove 43, the flat solid surface of the stationary sleeve 41 directly blocks its continued descent. After the system completes the specified number of pressure tests, the upper component rotates to align with the unlocking guide groove 43. Then, the upper component slides directly down along the unlocking guide groove 43 into the interior of one side of the inner stationary tube 42, realizing a deep sinking action.

[0022] Please see the appendix Figure 4 - Appendix Figure 7The pressure testing and counting mechanism 5 is located on the stationary locking mechanism 4. Together with the stationary sleeve 41, the embedded stationary cylinder 42, the unlocking guide groove 43, and the reset snap ring 44, it forms a rotatable multiple test switching structure. The pressure testing and counting mechanism 5 is set on the stationary locking mechanism 4. After receiving the downward linear thrust transmitted from the upper mechanism, the pressure testing and counting mechanism 5 slides down along the outer wall of the stationary locking mechanism 4. During the downward movement, the pressure testing and counting mechanism 5 is subjected to the lateral inclined plane pushing force. This lateral force forces the pressure testing and counting mechanism 5 to rotate at a small angle along the stationary locking mechanism 4. When the external downward pressure is released, the pressure testing and counting mechanism 5 is pushed upward by the stationary locking mechanism 4 and rises back. During the retraction, it continues to be guided by the inclined plane track to complete the remaining angle of rotation, thereby realizing the switching of the mechanical test station. Please see the appendix Figure 4 - Appendix Figure 10 The pressure testing and counting mechanism 5 includes a rotating sleeve 51, which slides along the outer ring of the stationary sleeve 41 and the inner wall of the rotating sleeve 51 abuts against the reset spring 44. The trapezoidal guide strips 52 are arranged opposite each other on both sides of the rotating sleeve 51. The elastic force of the reset spring 44 can keep the trapezoidal guide strips 52 in contact with the synchronous switching mechanism 7. The externally transmitted downward thrust acts directly on the top inclined surface of the trapezoidal guide strips 52, forcing the rotating sleeve 51 to slide downward along the outer ring of the stationary sleeve 41 and press down on the reset spring 44. During this process, the trapezoidal guide strips 52 are subjected to the lateral inclined surface pressure applied from above and slide laterally along the inclined surface. This lateral sliding force directly drives the rotating sleeve 51 to produce a lateral rotation. During this period, the reset spring 44 pushes the rotating sleeve 51 upward, so that the trapezoidal guide strips 52 are tightly attached to the upper mechanism, ensuring that each vertical lifting and lowering can be stably converted into rotation. Please see the appendix Figure 10 - Appendix Figure 11 The top contact strip 53 is set on the inner wall of the rotating sleeve 51 and can be embedded and slid into the unlocking guide groove 43. During the pressure test, when the top contact strip 53 descends synchronously with the rotating sleeve 51, the bottom end of the top contact strip 53 directly impacts and hard abuts against the flat end surface of the stationary sleeve 41, directly preventing the rotating sleeve 51 from continuing to sink. After the rotating sleeve 51 has undergone multiple pressures and completed the rotation switching, the top contact strip 53 moves to a position flush with the unlocking guide groove 43. When it is subjected to downward thrust again, the top contact strip 53 successfully pierces in and slides down along the unlocking guide groove 43, enabling the rotating sleeve 51 to sink to a great depth.

[0023] Please see the appendix Figure 11 - Appendix Figure 13The sealing and pushing mechanism 6 is located on the outer sleeve 1, and works with the central guide tube of the outer sleeve 1 and the stationary sleeve 41 to form a pressure receiving structure during pressure testing and operation. The sealing and pushing mechanism 6 is set at the port of the central guide tube of the outer sleeve 1 and embedded in the central guide tube. Please see the appendix Figure 12 - Appendix Figure 13 The sealing and pushing mechanism 6 includes a piston inner cylinder 61, which slides along the inner wall of the closed ring sleeve mechanism 3. The piston inner cylinder 61 is simultaneously placed in contact with the pushing ring 34. The linkage toothed cylinder 62 is fixed inside the piston inner cylinder 61 and embedded in the central guide cylinder of the outer sleeve 1. The bottom end of the linkage toothed cylinder 62 is provided with circumferentially distributed conical teeth. External fluid pressure is directly applied to the top end face of the piston inner cylinder 61, driving the piston inner cylinder 61 to slide downward. When the piston inner cylinder 61 descends, it drags the linkage toothed cylinder 62 down together. The bottom end of the piston inner cylinder 61 will gradually approach the pushing ring 34. After the linkage toothed cylinder 62 moves down into the depth of the outer sleeve 1, the conical teeth at the bottom end of the linkage toothed cylinder 62 directly press down on the rotating sleeve 51 component below. The inclined surface of the conical teeth converts the downward linear thrust into a lateral pushing force that forces the lower mechanism to rotate laterally. Please see the appendix Figure 12 - Appendix Figure 13 The piston inner cylinder 61 has a fixed fitting shaft 64 inside, which faces the inner stationary cylinder 42 and can be embedded into the inner stationary cylinder 42. The end of the fitting shaft 64 is provided with a locking step block 65 that has internal and external elastic extension. When the piston inner cylinder 61 slides down to a great depth, it drives the fitting shaft 64 to continuously penetrate deeper into the inner cavity of the inner stationary cylinder 42. When the fitting shaft 64 slides completely into the internal space of the inner stationary cylinder 42, the locking step block 65 at the end of the fitting shaft 64 gets rid of the constraint of the narrow external space. The locking step block 65 uses its own accumulated elasticity to spring open and extend outward. After extension, the locking step block 65 directly locks against the inner wall structure of the inner stationary cylinder 42, so that the piston inner cylinder 61 is firmly pulled and cannot be retracted upward.

[0024] Please see the appendix Figure 11 - Appendix Figure 13 The synchronous switching mechanism 7 is located in the outer sleeve 1, and works with the push ring 34, the rotating sleeve 51, the trapezoidal guide strip 52, the conical tooth key of the linkage toothed cylinder 62, and the anti-rotation guide strip 63 to form a limited switching structure that can be tested multiple times. The synchronous switching mechanism 7 is statically embedded in the central guide cylinder of the outer sleeve 1 and is placed between the test counting mechanism 5 and the sealing push mechanism 6. Please see the appendix Figure 11 - Appendix Figure 13The synchronous switching mechanism 7 includes a stationary toothed cylinder 71, which is fixed inside the central sleeve of the outer sleeve 1, and allows the linkage toothed cylinder 62 to be embedded inside. The bottom edge of the stationary toothed cylinder 71 is a circumferentially distributed and interlocking trapezoidal guide groove, and the inclined surface of the trapezoidal guide groove corresponds to the inclined surface of the conical tooth key of the linkage toothed cylinder 62. At the same time, it can be in contact with the top inclined surface of the trapezoidal guide strip 52. When the linkage toothed cylinder 62 slides down into the stationary toothed cylinder 71, the anti-rotation guide strip 63 directly... The guide bar 63 slides inside the anti-rotation guide groove 72. The hard side wall of the anti-rotation guide groove 72 prevents the anti-rotation guide bar 63 from deflecting laterally, forcing the linkage toothed cylinder 62 to maintain a pure straight downward trajectory. At the same time, the trapezoidal guide groove slope of the bottom edge of the stationary toothed cylinder 71 and the conical tooth key slope of the linkage toothed cylinder 62 intersect and approach each other, jointly clamping the top slope of the trapezoidal guide bar 52. This interlocking slope pressure forces the trapezoidal guide bar 52 to slide along the slope, completing a precise angle switch. Please see the appendix Figure 12 - Appendix Figure 13 The stationary toothed cylinder 71 has a corresponding anti-rotation guide groove 72 inside, which is connected and wedges with the anti-rotation guide strip 63, so that the piston inner cylinder 61 cannot rotate.

[0025] Based on the above technical solution, this embodiment of the invention also provides a working principle of a multi-test pressure mechanical sliding rail toe sleeve, including the following: First, the toe sleeve is assembled and fixed by an outer sleeve 1 and pre-embedded in the interior of the shale layer. External fluid inputs pressure to the end sleeve 2, and the end sleeve 2 guides the fluid pressure to the interior of the outer sleeve 1, and directly acts on the piston inner cylinder 61 of the sealing and pushing mechanism 6. After receiving continuous fluid pressure, the piston inner cylinder 61 slides downward along the inner wall of the closed sleeve 31. The piston inner cylinder 61 drives the linkage toothed cylinder 62 to slide downward together. During the downward movement, the anti-rotation guide strip 63 on the outside of the linkage toothed cylinder 62 and the anti-rotation guide groove 72 inside the stationary toothed cylinder 71 of the synchronous switching mechanism 7 are connected. During the docking and sliding process, the anti-rotation guide bar 63, constrained by the anti-rotation guide groove 72, forces the linkage toothed cylinder 62 to only undergo a linear descent without rotation. After the linkage toothed cylinder 62 penetrates into the stationary toothed cylinder 71, the tapered key at the bottom of the linkage toothed cylinder 62 directly presses down on the top inclined surface of the trapezoidal guide bar 52 of the pressure counting mechanism 5. Since the trapezoidal guide bar 52 is connected to the rotating sleeve 51, this downward thrust forces the rotating sleeve 51 to slide downward along the outer ring of the stationary sleeve 41. The descent of the rotating sleeve 51 simultaneously squeezes the reset spring 44 of the stationary locking mechanism 4, causing the reset spring 44 to undergo elastic compression and store force. During the downward descent of the rotating sleeve 51 under pressure, the tapered key inclined surface of the linkage toothed cylinder 62 cooperates with the stationary toothed cylinder 71. The trapezoidal guide grooves at the bottom edges of cylinder 71, which interlock, exert a lateral sliding guiding force on the trapezoidal guide strip 52. Since the linkage toothed cylinder 62 is constrained and cannot rotate, its downward linear thrust forces the trapezoidal guide strip 52 to slide laterally along the slope of the trapezoidal guide groove. This lateral sliding directly drives the rotating sleeve 51 to rotate at a small angle along the outer ring of the stationary sleeve 41. During the pressure test, the top contact strip 53 on the inner wall of the rotating sleeve 51 is not aligned with the unlocking guide groove 43 of the stationary locking mechanism 4. The bottom end of the top contact strip 53 directly abuts against the solid end face of the stationary sleeve 41. This rigid contact hinders the further descent of the rotating sleeve 51, thus strictly limiting the sinking depth of the piston inner cylinder 61. This limited sinking depth causes the piston inner cylinder 61 to... Unable to reach the push ring 34, the closed sleeve 31 remains in place under the support of the reset snap ring 33. The closed material channel 32 is not connected to the fracturing groove of the outer sleeve 1, thus maintaining the closed state inside the tubing and completing one pressure test. After the single test, the fluid pressure input to the end sleeve 2 is released, the piston inner sleeve 61 loses its downward thrust, the reset snap ring 44 releases the stored elastic potential energy, and pushes the rotating sleeve 51 upward. When the rotating sleeve 51 retracts upward, the trapezoidal guide strip 52 slides again along the reverse slope of the trapezoidal guide groove of the stationary toothed cylinder 71, driving the rotating sleeve 51 to continue to complete the remaining angle of rotation, so that the trapezoidal guide strip 52 slides completely into the adjacent trapezoidal guide groove of the stationary toothed cylinder 71. The rotating sleeve 51 descends under pressure and rebounds after pressure relief.The inclined plane guides the rotational switching of one workstation, thus performing one mechanical pressure test count. This process is repeated multiple times. The rotating sleeve 51 rotates step-by-step using the downward pressure of the linkage toothed cylinder 62 and the inclined plane guidance of the stationary toothed cylinder 71. When the final test is completed and fracturing operations are ready, the rotating sleeve 51 rotates to a specific angle, ensuring the top contact strip 53 on the inner wall of the rotating sleeve 51 is fully aligned with the unlocking guide groove 43. High-pressure fluid is then input again through the end sleeve 2. Force drives the piston inner sleeve 61 and the linkage toothed sleeve 62 to push the rotating sleeve 51 downward. Because the top contact bar 53 is already aligned with the unlocking guide groove 43, when the rotating sleeve 51 descends, the top contact bar 53 directly embeds and slides downward along the unlocking guide groove 43. This sliding process causes the rotating sleeve 51 to exhibit a sinking depth far exceeding that of the test phase. The increase in the sinking depth of the rotating sleeve 51 removes the limitation on the descent stroke of the piston inner sleeve 61. The piston inner sleeve 61 continues to penetrate deeper, and its bottom end directly contacts the push ring 34. The downward thrust is transmitted to the push ring 34. Under this force, the push ring 34 causes the closed sleeve 31 to slide downwards against the elastic force of the reset spring 33. The downward movement of the closed sleeve 31 pushes its outer closed channel 32 to a state where it connects with the fracturing groove on the outer sleeve 1. The high-pressure fracturing fluid delivered by the end sleeve 2 passes through the closed channel 32 and is sprayed outwards from the fracturing groove of the outer sleeve 1, performing the fracturing operation. During the descent of the piston inner sleeve 61, its internal insert... The inserting shaft 64 simultaneously penetrates the inner stationary cylinder 42. When the piston inner stationary cylinder 61 reaches its maximum pressing depth, the inserting shaft 64 is fully inserted into the inner stationary cylinder 42. The locking step block 65 at the end of the inserting shaft 64, after entering the inner stationary cylinder 42, elastically extends outward, causing the locking step block 65 to tightly engage and lock inside the inner stationary cylinder 42. This engaging action locks the piston inner stationary cylinder 61 and the sealing sleeve 31 in the open state, maintaining the continuous unobstructed flow of the fracturing channel.

[0026] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A mechanical slide rail type toe end sleeve subjected to multiple pressure tests, characterized in that, include: External sleeve (1) is used for the combination of toe end sliding sleeve structure; The end sleeve (2) is located on the outer sleeve (1) and is used to form the input end portion of the toe sleeve; The closed ring mechanism (3) is located on the outer sleeve (1) and is used in conjunction with the fracturing groove of the outer sleeve (1) to form an open and closed sleeve structure that can be closed and unblocked. The stationary locking mechanism (4) is located on the outer sleeve (1) and works with the central guide tube of the outer sleeve (1) to form a stationary reverse push test switching structure. The pressure test counting mechanism (5) is located in the stationary locking mechanism (4), and works with the stationary sleeve (41), the embedded stationary cylinder (42), the unlocking guide groove (43) and the reset snap ring (44) to form a rotatable multiple test switching structure. The sealing and pushing mechanism (6) is located in the outer sleeve (1), and works with the central guide tube of the outer sleeve (1) and the stationary sleeve (41) to form a pressure receiving structure during pressure testing and operation; The synchronous switching mechanism (7) is located on the outer sleeve (1), and works with the push ring (34), the rotating sleeve (51), the trapezoidal guide strip (52), the conical tooth key of the linkage toothed cylinder (62), and the anti-rotation guide strip (63) to form a limited number switching structure that can be tested multiple times.

2. The toe end sleeve of a mechanical slide rail type for multiple pressure testing according to claim 1, characterized in that, The central guide tube of the outer sleeve (1) is fixed at the end of the outer sleeve (1) and extends into the interior of the outer sleeve (1). The fracturing slots are distributed in a linear parallel pattern on the outer sleeve (1). The end sleeve (2) is engaged at the input end of the outer sleeve (1) as the connection port of the external pressure pipe. The closing ring mechanism (3) is embedded in the interior of the outer sleeve (1) and can contact the inner wall of the end sleeve (2). The stationary locking mechanism (4) is set in the central sleeve of the outer sleeve (1) and close to the end of the outer sleeve (1). The pressure test counting mechanism (5) is set on the stationary locking mechanism (4). The sealing pushing mechanism (6) is set at the port of the central guide tube of the outer sleeve (1) and embedded in the central guide tube. The synchronous switching mechanism (7) is stationarily embedded in the central guide tube of the outer sleeve (1) and placed between the pressure test counting mechanism (5) and the sealing pushing mechanism (6).

3. The toe end sleeve of a mechanical slide rail type for multiple pressure testing according to claim 1, characterized in that, The closed ring mechanism (3) includes a closed sleeve (31), which is embedded in the outer sleeve (1) and its end is connected to the inner wall of the outer sleeve (1) through a reset snap ring (33). The other end of the closed sleeve (31) is attached to the end of the end sleeve (2). A circumferentially distributed closed material channel (32) is provided on the outside of the closed sleeve (31) and is parallel to the fracturing groove of the outer sleeve (1). The push ring (34) is fixed on the inner wall of the closed sleeve (31) and is attached to the central guide tube of the outer sleeve (1).

4. The toe end sleeve of a mechanical slide rail type for multiple pressure testing according to claim 1, characterized in that, The stationary locking mechanism (4) includes a stationary sleeve (41), which is fixed to the inner wall of the central guide tube of the outer sleeve (1) and close to the end of the outer sleeve (1). The embedded stationary tube (42) is fixed inside the stationary sleeve (41). The unlocking guide groove (43) is provided on the side of the stationary sleeve (41). The reset snap ring (44) is provided on the side wall of the embedded stationary tube (42) facing the pressure counting mechanism (5).

5. The toe-end sliding sleeve of a mechanical slide rail type for multiple pressure testing according to claim 1, characterized in that, The pressure testing counting mechanism (5) includes a rotating sleeve (51), which slides along the outer ring of the stationary sleeve (41), and the inner wall of the rotating sleeve (51) abuts against the reset snap ring (44). The trapezoidal guide strip (52) is arranged opposite to each other on both sides of the rotating sleeve (51). The elastic force of the reset snap ring (44) can keep the trapezoidal guide strip (52) in contact with the synchronous switching mechanism (7) at all times.

6. The toe end sleeve of a mechanical slide rail type for multiple pressure testing according to claim 1, characterized in that, The sealing and pushing mechanism (6) includes a piston inner cylinder (61), which slides along the inner wall of the closed ring sleeve mechanism (3) and is simultaneously placed in contact with the pushing ring (34). The linkage toothed cylinder (62) is fixed inside the piston inner cylinder (61) and embedded into the central guide cylinder of the outer sleeve (1). The bottom end of the linkage toothed cylinder (62) is provided with circumferentially distributed conical teeth.

7. The toe end sleeve of a mechanical slide rail type for multiple pressure testing according to claim 1, characterized in that, The synchronous switching mechanism (7) includes a stationary toothed cylinder (71), which is fixed inside the central sleeve of the outer sleeve (1) and allows the linkage toothed cylinder (62) to be embedded inside. The bottom edge of the stationary toothed cylinder (71) is a trapezoidal guide groove that is circumferentially distributed and interlocked with each other. The inclined surface of the trapezoidal guide groove corresponds to the inclined surface of the conical tooth key of the linkage toothed cylinder (62) and can also be in contact with the top inclined surface of the trapezoidal guide strip (52).

8. The toe end sleeve of a mechanical slide rail type for multiple pressure testing according to claim 5, characterized in that, The top contact bar (53) is located on the inner wall of the rotating sleeve (51) and can be inserted into the unlocking guide groove (43).

9. The toe end sleeve of a mechanical slide rail type for multiple pressure tests according to claim 6, characterized in that, The piston inner cylinder (61) has a fitting and embedding shaft (64) fixed inside, facing the inner stationary cylinder (42), and can be embedded into the inner stationary cylinder (42). The end of the fitting and embedding shaft (64) is provided with a locking step block (65) that can be elastically extended and retracted inside and outside.

10. The toe-end sliding sleeve of a mechanical slide rail type for multiple pressure testing according to claim 7, characterized in that, The stationary toothed cylinder (71) has a corresponding anti-rotation groove (72) inside, which is connected and wedges with the anti-rotation strip (63).

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