Self-locking cement non-return sliding sleeve for one-trip half-way well cementation and anti-reflux control method

Abstract

The invention discloses a self-locking cement non-return sliding sleeve for one-trip half-way well cementation and an anti-reflux control method, and relates to the technical field of oil and gas well cementation, the self-locking cement non-return sliding sleeve comprises a well cementation non-return mechanism, the well cementation non-return mechanism comprises an upper connector, the upper connector is fixedly connected with an outer shell, the outer shell is fixedly connected with a connecting cylinder, the lower end of the connecting cylinder is fixedly connected with a lower connector, and the lower connector is fixedly connected with the lower end of the connecting cylinder. An anti-return sliding sleeve is slidably connected between the outer shell and the connecting cylinder, a driving sliding sleeve is slidably connected in the outer shell, a fracturing inner hole is formed in the surface of the outer shell, and a fracturing outer hole is formed in the surface of the connecting cylinder. By means of the well cementation non-return mechanism, the anti-return sliding sleeve can move upwards to reset after injection is completed, the situations that cement flows reversely, interlayer packing fails, the sealing performance of a cement sheath is reduced, and even annulus pressure is abnormal are avoided, the well cementation effect is improved, the sliding sleeve is driven to reset with the help of a tool subsequently, the secondary plugging effect is achieved, and the well cementation effect is improved. And cement is prevented from flowing reversely.

Description

Technical Field

[0001] The invention relates to the technical field of oil and gas well cementing, in particular to a self-locking cement check sleeve for one-trip half-stroke cementing and a backflow prevention control method. Background Art

[0002] The one-trip half-stroke cementing process technology is to install a special cementing tool, a staged cementing sleeve, at a set position in the casing string in the well. During cementing, a special process is used to cement the annular spaces of the casing annulus in the upper and lower sections of the staged cementing sleeve separately.

[0003] However, in practical applications, there are still some unresolved problems. The following are some common problems in one-trip half-stroke cementing: In the initial state, the sliding sleeve is fixed in the open position by shear pins to keep the circulation channel unobstructed and facilitate the injection of cementing fluid. After the cement slurry is injected, the shear pins are triggered by pump pressure to cut off, pushing the sliding sleeve downward to close the channel. When the sliding sleeve moves to the set position, the retaining ring or spring is embedded in the main body groove, forming a permanent mechanical lock, resulting in the sliding sleeve being unable to reset after the injection is completed, causing cement to flow backward, which may lead to failure of the interlayer seal, reduced sealing of the cement ring, and even abnormal annular pressure. Summary of the Invention

[0004] In view of the above problems existing in the existing one-trip half-stroke cementing, the present invention is proposed.

[0005] Therefore, the problem to be solved by the present invention is how to solve the problem that the sleeve cannot be reset after injection is completed, causing cement to flow backward, which may lead to interlayer sealing failure, reduced cement ring sealing, and even abnormal annular pressure.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions: a self-locking cement check sleeve for one-trip half-stroke cementing, which comprises:

[0007] The cementing non-return mechanism includes an upper joint, the upper joint is fixedly connected to an outer shell, the outer shell is fixedly connected to a connecting cylinder, the lower end of the connecting cylinder is fixedly connected to a lower joint, an anti-return sleeve is slidably connected between the outer shell and the connecting cylinder, a driving sleeve is slidably connected inside the outer shell, an inner fracturing hole is opened on the surface of the outer shell, an outer fracturing hole is opened on the surface of the connecting cylinder, a connecting head is fixedly connected to the lower joint, and a cylindrical coil spring is provided between the lower joint and the anti-return sleeve.

[0008] As a preferred solution of the self-locking cement check sleeve for one-trip half-stroke cementing described in the present invention, a limited unlocking mechanism is installed on the outer shell and the anti-return sleeve, and is arranged on the driving sleeve. The limited unlocking mechanism includes a limited assembly installed on the outer shell, and a blocking assembly is installed on the outer shell and the anti-return sleeve, and is arranged on the limited assembly.

[0009] As a preferred solution of the self-locking cement check sleeve for one-trip half-stroke cementing described in the present invention, the limiting assembly includes a groove body opened in the outer shell, a circular shell is slidably connected to the groove body, a clamping block is slidably connected to the outer shell, one end of the clamping block passes through the circular shell and is fixedly connected to the connecting block, a telescopic spring is fixedly connected between the surface of the connecting block and the inner wall of the circular shell, a clamping groove matching the clamping block is opened on the inner wall of the anti-return sleeve, and the clamping block is inserted into the clamping groove.

[0010] As a preferred solution of the self-locking cement check sleeve for one-trip half-stroke cementing described in the present invention, a short block is fixedly connected to the surface of the circular shell, a short column is fixedly connected to the connecting block, a limiting groove is provided on the inner wall of the tank body, and the limiting block is fixedly connected to the outer surface of the circular shell, and is slidably connected in the limiting groove.

[0011] As a preferred solution of the self-locking cement check sleeve for one-trip half-stroke cementing described in the present invention, the blocking component includes an air groove opened in the outer shell, a guide plate is slidably connected to the outer shell, and it passes through the air groove, a fixed block is fixedly connected to the upper end of the guide plate, and it is fixedly connected to the surface of the driving sleeve, a guide hole is opened on the surface of the guide plate, and a short column is slidably connected therein.

[0012] As a preferred solution of the self-locking cement check sleeve for one-trip half-stroke cementing described in the present invention, a piston is slidably connected in the air groove and is sleeved on the guide plate, an air bag is embedded in the outer shell, a hose is connected to the air bag, one end of the hose passes through the outer shell and is connected to the air groove, and adjacent air bags are connected by connecting pipes.

[0013] As a preferred solution of the self-locking cement check sleeve for one-trip half-stroke cementing described in the present invention, a sealing ring is provided between the piston and the air groove, and the sealing ring is sleeved on the surface of the piston; a sealing sleeve is provided between the guide plate and the outer shell, and the sealing sleeve is sleeved on the surface of the guide plate.

[0014] As a preferred solution of the self-locking cement check sleeve for one-trip half-stroke cementing described in the present invention, a reflux mechanism is installed on the outer shell, including a through hole and a groove opened on the outer shell, a valve assembly is installed in the through hole and the groove, and a sliding groove is opened on the outer surface of the driving sleeve, which cooperates with the valve assembly.

[0015] As a preferred solution of the self-locking cement check sleeve for one-trip half-stroke cementing described in the present invention, the valve assembly includes a block slidably connected to the groove, and its surface is in contact with the through hole, an L-shaped plate is slidably connected to the outer shell, and one end of the L-shaped plate is fixedly connected to the bottom of the block, and the other end is slidably connected to the slide groove, and a spring is fixedly connected between the block surface and the inner wall of the groove.

[0016] As a preferred solution of the anti-backflow control method of the self-locking cement check sleeve for one-trip half-stroke cementing according to the present invention, in which: in the initial state, the driving sleeve and the anti-backflow sleeve are both in the closed state, and no liquid flows between the inside and outside of the anti-backflow sleeve. The specific operation is: the anti-backflow sleeve is brought to the specified position along the cementing string, and the driving sleeve is moved downward and then opened by the action of the sleeve switch tool, and in this process, the limit unlocking mechanism is driven so that the block on the limit assembly realizes the preliminary unlocking of the anti-backflow sleeve, and the air bag on the blocking assembly is contracted into the anti-backflow sleeve;

[0017] The liquid passes through the fracturing inner hole and reaches the chamber formed between the outer shell and the connecting tube. As the pressure inside the chamber increases, the anti-return sleeve drives the block, causing the block to move into the round shell. The liquid inside the driving sleeve pushes the anti-return sleeve downward until the fracturing outer hole is opened. The liquid inside the driving sleeve is transmitted to the outside of the device through the fracturing inner hole, the chamber, and the fracturing outer hole in sequence. The pressure is transmitted to the outside, establishing a communication channel between the ground and the fracturing formation.

[0018] When the surface pump stops working or the formation pressure is higher than the driving sleeve pressure, the internal pressure of the anti-backflow sleeve decreases to the pre-pressure of the cylindrical coil spring. The cylindrical coil spring pushes the anti-backflow sleeve to close, blocking the connection between the inside of the device and the formation, preventing cement from flowing backward. The service tool is lifted, and the switch tool drives the driving sleeve to the closed position, achieving complete isolation between the formation and the inside of the pipe string.

[0019] The beneficial effects of the present invention are as follows: the cementing non-return mechanism can prevent the backflow sleeve from moving upward and resetting after the injection is completed, thereby avoiding reverse flow of cement, which would lead to failure of interlayer isolation, reduced sealing of cement ring, and even abnormal annular pressure, thereby improving the cementing effect, and driving the sleeve to be reset with the help of tools, thereby playing a secondary plugging role and avoiding reverse flow of cement. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0021] Figure 1 This is an overall three-dimensional structural diagram of a self-locking cement check sleeve and a backflow prevention control method for one-trip half-stroke cementing.

[0022] Figure 2 This is a cross-sectional plan view of the self-locking cement check sleeve and the anti-backflow control method for one-trip half-stroke cementing.

[0023] Figure 3 This is a partial cross-sectional three-dimensional structural diagram of a self-locking cement check sleeve and a backflow prevention control method for one-trip half-stroke cementing.

[0024] Figure 4 This diagram shows the local structural changes during the alternating travel of a self-locking cement check sleeve and an anti-backflow control method for one-trip half-stroke cementing.

[0025] Figure 5 Self-locking cement check sleeve and backflow prevention control method for one-trip half-stroke cementing Figure 2 A magnified structural diagram.

[0026] Figure 6 Self-locking cement check sleeve and backflow prevention control method for one-trip half-stroke cementing Figure 2 A magnified structural diagram of B.

[0027] Figure 7 Self-locking cement check sleeve and backflow prevention control method for one-trip half-stroke cementing Figure 2 Enlarged structure diagram of C in the middle.

[0028] Figure 8 This is a partially cutaway stereoscopic structural diagram of the outer shell and connecting tube of a self-locking cement check sleeve and a backflow prevention control method for one-trip half-stroke cementing.

[0029] Figure 9 Self-locking cement check sleeve and backflow prevention control method for one-trip half-stroke cementing Figure 8 Enlarged structural diagram of D in the middle.

[0030] Figure 10 This is a cross-sectional plan view of the outer shell and anti-return sleeve of a self-locking cement check sleeve and anti-backflow control method for one-trip half-stroke cementing.

[0031] Figure 11 This is a partial three-dimensional structural diagram of the guide plate of the self-locking cement check sleeve and the anti-backflow control method used in one-trip half-stroke cementing.

[0032] Figure 12 This is a three-dimensional structural diagram of the outer shell of a self-locking cement check sleeve and anti-backflow control method for one-trip half-stroke cementing.

[0033] In the figure: 1. Cementing check mechanism; 11. Upper joint; 12. Outer shell; 13. Connecting tube; 14. Lower joint; 15. Anti-return sleeve; 16. Driving sleeve; 17. Fracturing inner hole; 18. Fracturing outer hole; 19. Connecting head; 110. Cylindrical coil spring; 2. Limit unlocking mechanism; 21. Limit assembly; 22. Blocking assembly; 21-1. Trough; 21-2. Round shell; 21-3. Block; 21-4. Connecting block; 21-5. Telescopic spring; 21-6. Slot; 21-7. Short Block; 21-8, short column; 21-9, limit groove; 21-10, limit block; 22-1, air groove; 22-2, guide plate; 22-3, fixed block; 22-4, piston; 22-5, air bag; 22-6, hose; 22-7, connecting pipe; 22-8, guide hole; 22-9, sealing ring; 22-10, sealing sleeve; 3, reflux mechanism; 31, through hole; 32, groove; 33, valve assembly; 34, slide; 33-1, stopper; 33-2, L-shaped plate; 33-3, spring. DETAILED DESCRIPTION

[0034] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0035] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0036] Secondly, the term "one embodiment" or "embodiment" herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in various places throughout this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive of other embodiments.

[0037] Example 1

[0038] Reference Figures 1 to 3 , which is the first embodiment of the present invention, provides a self-locking cement check sleeve and anti-backflow control method for one-trip half-stroke cementing. The self-locking cement check sleeve and anti-backflow control method for one-trip half-stroke cementing include a cementing check mechanism 1. The cementing check mechanism 1 can move the anti-backflow sleeve 15 upward and reset after the injection is completed, thereby avoiding reverse flow of cement, resulting in failure of interlayer isolation, reduced sealing of the cement ring, and even abnormal annular pressure, thereby improving the cementing effect.

[0039] Specifically, the cementing non-return mechanism 1 includes an upper joint 11, to which an outer shell 12 is fixedly connected, to which a connecting tube 13 is fixedly connected, and to which a lower joint 14 is fixedly connected at the lower end of the connecting tube 13. An anti-return sleeve 15 is slidably connected between the outer shell 12 and the connecting tube 13, and a guide groove and a guide block are provided between the anti-return sleeve 15 and the connecting tube 13 to prevent the anti-return sleeve 15 from rotating during movement. A driving sleeve 16 is slidably connected inside the outer shell 12, and a fracturing inner hole 17 is provided on the surface of the outer shell 12, and a fracturing outer hole 18 is provided on the surface of the connecting tube 13. The number of the fracturing inner holes 17 and the number of the fracturing outer holes 18 are both several.

[0040] A connecting head 19 is fixedly connected to the lower joint 14, and the upper end of the connecting head 19 is in contact with the lower end of the outer shell 12. The fixed connection method between the upper joint 11, the outer shell 12, the connecting tube 13, the lower joint 14, the anti-return slip sleeve 15 and the connecting head 19 all adopts a detachable connection scheme, which is the existing technology and can be clearly understood by those skilled in the art. It will not be elaborated here. A cylindrical coil spring 110 is arranged between the lower joint 14 and the anti-return slip sleeve 15.

[0041] By driving the sleeve 16 with the help of the sleeve switching tool, it moves downward and opens, exposing the fracturing inner hole 17. The liquid passes through the fracturing inner hole 17 to the chamber formed between the outer shell 12 and the connecting tube 13. With the pressure inside the chamber, the internal liquid pushes the anti-return sleeve 15 to move downward until the fracturing outer hole 18 is opened. The internal liquid passes through the fracturing inner hole 17, the chamber, and the fracturing outer hole 18 in turn and is transmitted to the outside of the device. The pressure is transmitted to the outside to establish a communication channel between the ground and the fracturing formation. When the ground pump stops working or the formation pressure is higher than the pressure of the driving sleeve 16, the internal pressure of the anti-return sleeve 15 is reduced to the pre-pressure of the cylindrical coil spring 110. The cylindrical coil spring 110 pushes the anti-return sleeve 15 to close, blocking the communication between the inside of the device and the formation, and preventing cement from flowing backward.

[0042] Example 2

[0043] Reference Figures 2 to 12 , which is the second embodiment of the present invention, and this embodiment is based on the previous embodiment.

[0044] Specifically, a limit unlocking mechanism 2 is installed on the outer shell 12 and the anti-return sliding sleeve 15, and is arranged on the driving sliding sleeve 16. The limit unlocking mechanism 2 includes a limit component 21 installed on the outer shell 12, and a blocking component 22 is installed on the outer shell 12 and the anti-return sliding sleeve 15, and is arranged on the limit component 21.

[0045] The limit unlocking mechanism 2 can be used to initially unlock the anti-return sleeve 15 when the sliding sleeve 16 is driven to move downward, and then the anti-return sleeve 15 is pushed downward by the pressure of the liquid to achieve complete unlocking, and continue to move downward until the fracturing outer hole 18 is opened. After the use is completed and reset, the anti-return sleeve 15 can still be limited and fixed, and it can be recycled to some extent. The blocking component 22 thereon can not hinder the normal movement of the anti-return sleeve 15 when unlocking and moving it downward, and can seal the fracturing outer hole 18 after moving upward and resetting to prevent cement from solidifying therein, and prevent it from being unable to operate again when secondary cementing is required.

[0046] The limiting assembly 21 includes a groove body 21-1 opened in the outer shell 12, and a circular shell 21-2 is slidably connected in the groove body 21-1. A card block 21-3 is slidably connected to the outer shell 12, and one end of the card block 21-3 passes through the circular shell 21-2 and is fixedly connected to the connecting block 21-4. Through the arrangement of the circular shell 21-2 and the connecting block 21-4, when the side where the connecting block 21-4 is connected to the card block 21-3 contacts the inner wall of the circular shell 21-2, when the circular shell 21-2 moves toward the short block 21-7, it can drive the connecting block 21-4 and the card block 21-3 to move together. At this time, when the corresponding driving sleeve 16 moves downward, the card block 21-3 moves to initially unlock the anti-return sleeve 15.

[0047] A telescopic spring 21-5 is fixedly connected between the surface of the connecting block 21-4 and the inner wall of the round shell 21-2. A slot 21-6 is provided on the inner wall of the anti-return sliding sleeve 15 to match the block 21-3. The block 21-3 is inserted into the slot 21-6. A slope is provided at one end of the block 21-3, and a slope is provided in the slot 21-6. Through such a setting, when the driving sleeve 16 moves down a certain distance, the block 21-3 on it moves a certain distance under the transmission of the limit unlocking mechanism 2, and the block 21-3 is gradually moved out of a part of the slot 21-6, completing the preliminary unlocking, so that the slope on the block 21-3 corresponds to the slope on the slot 21-6.

[0048] When the anti-return sleeve 15 is acted on by the pressure of the liquid, the anti-return sleeve 15 squeezes the block 21-3 to move it, and the block 21-3 is completely separated from the slot 21-6 and is completely unlocked, and the anti-return sleeve 15 can move downward under the pressure of the liquid, and continue to move downward until the fracturing outer hole 18 is opened, and the anti-return sleeve 15 can still move upward and reset smoothly, so that the block 21-3 rebounds and is initially inserted into the slot 21-6. In the subsequent process of driving the sleeve 16 to move back, the round shell 21-2 is moved through the corresponding transmission to squeeze the telescopic spring 21-5 to act on the block 21-3, so that the block 21-3 moves into the slot 21-6 to complete the limit fixation.

[0049] Through the setting of the telescopic spring 21-5, when the slot 21-6 on the anti-return slip sleeve 15 squeezes the block 21-3, the block 21-3 has space to move. In the subsequent resetting process, when the block 21-3 is opposite to the slot 21-6, the circular shell 21-2 acts on the telescopic spring 21-5 to push the connecting block 21-4 and the block 21-3 to move.

[0050] A short block 21-7 is fixedly connected to the surface of the circular shell 21-2, and the short block 21-7 indirectly connects the short column 21-8 and the circular shell 21-2. A short column 21-8 is fixedly connected to the connecting block 21-4, and when the short column 21-8 moves in the guide hole 22-8 on the guide plate 22-2, the short block 21-7 can be moved or not moved, thereby moving the circular shell 21-2 when the driving sleeve 16 moves downward, and resetting the circular shell 21-2 when the driving sleeve 16 moves upward and resets.

[0051] A limiting groove 21-9 is provided on the inner wall of the trough body 21-1, and a limiting block 21-10 is fixedly connected to the outer surface of the circular shell 21-2, and is slidably connected to the limiting groove 21-9. The limiting groove 21-9 and the limiting block 21-10 can guide and limit the circular shell 21-2 to prevent it from rotating during movement.

[0052] The blocking assembly 22 includes an air groove 22-1 opened in the outer shell 12, and a guide plate 22-2 is slidably connected to the outer shell 12 and passes through the air groove 22-1. The upper end of the guide plate 22-2 is fixedly connected to a fixed block 22-3, and it is fixedly connected to the surface of the driving sleeve 16. The inner surface of the outer shell 12 is provided with a slot hole that matches the fixed block 22-3, so that the fixed block 22-3 will not be hindered when moving up and down with the driving sleeve 16. A guide hole 22-8 is opened on the surface of the guide plate 22-2, and a short column 21-8 is slidably connected therein.

[0053] The guide hole 22-8 is divided into three parts. When the short column 21-8 moves in the first and third parts, the short block 21-7 and the round shell 21-2 will not move. When the short column 21-8 moves in the second part, the short block 21-7 and the round shell 21-2 can move. When the driving sleeve 16 moves downward to open, the fixed block 22-3 and the guide plate 22-2 are driven to move. At this time, the short column 21-8 enters the third part from the first part through the second part. When the driving sleeve 16 moves upward to close, the fixed block 22-3 and the guide plate 22-2 are driven to move. At this time, the short column 21-8 enters the first part from the third part through the second part to reset, thereby completing the function of the limit assembly 21.

[0054] A piston 22-4 is slidably connected in the air groove 22-1 and is sleeved on the guide plate 22-2. An air bag 22-5 is embedded in the outer shell 12. A hose 22-6 is connected to the air bag 22-5. One end of the hose 22-6 passes through the outer shell 12 and is connected to the air groove 22-1. Adjacent air bags 22-5 are connected by a connecting pipe 22-7.

[0055] When the piston 22-4 moves downward with the guide plate 22-2, most of the gas in the airbag 22-5 is drawn into the air groove 22-1 through the hose 22-6, so that the airbag 22-5 retracts into the groove embedded in the anti-return sleeve 15, and does not hinder the subsequent downward movement of the anti-return sleeve 15. After the anti-return sleeve 15 moves up and resets, the guide plate 22-2 moves up with the driving sleeve 16 and the fixed block 22-3, so that the piston 22-4 moves up, and the gas in the air groove 22-1 is pressed into the airbag 22-5 through the hose 22-6, so that the airbag 22-5 expands to squeeze out the cement in the fracturing outer hole 18, and the fracturing outer hole 18 is sealed.

[0056] The material of the airbag 22-5 is not easy to bond with cement after solidification. This is existing technology and can be clearly understood by those skilled in the art, so it will not be elaborated here. There are several connecting pipes 22-7 and airbags 22-5. The connecting pipes 22-7 are used to keep the airbags 22-5 connected. When the piston 22-4 is running, multiple airbags 22-5 can be evacuated or inflated with the help of the hose 22-6.

[0057] A sealing ring 22-9 is provided between the piston 22-4 and the air groove 22-1. The sealing ring 22-9 is sleeved on the surface of the piston 22-4. The inner wall of the air groove 22-1 and the piston 22-4 are sealed by the sealing ring 22-9 to prevent gas from leaking from the gap therebetween. A sealing sleeve 22-10 is provided between the guide plate 22-2 and the outer shell 12. The sealing sleeve 22-10 is sleeved on the surface of the guide plate 22-2. The guide plate 22-2 and the outer shell 12 are sealed by the sealing sleeve 22-10 to prevent gas from leaking from the gap therebetween.

[0058] Example 3

[0059] Reference Figures 2 to 12 , which is the third embodiment of the present invention, is based on the first two embodiments.

[0060] Specifically, a reflux mechanism 3 is installed on the outer shell 12, including a through hole 31 and a groove 32 opened on the outer shell 12, a valve assembly 33 is installed in the through hole 31 and the groove 32, and a slide groove 34 is opened on the outer surface of the driving sleeve 16, which cooperates with the valve assembly 33.

[0061] Through the setting of the reflux mechanism 3, when the driving sleeve 16 moves downward, the limit unlocking mechanism 2 is acted on and the fluid injection is completed, and then the anti-return sleeve 15 moves back to close the fracturing outer hole 18, and then the driving sleeve 16 continues to move downward to open the through hole 31. With the help of an external suction device, the cement in the chamber formed between the outer shell 12 and the connecting tube 13 can be sucked out, so that a flow is formed between the fracturing inner hole 17, the chamber and the through hole 31, so that the cement can be fully sucked out better and the solidification in the chamber and the fracturing inner hole 17 is reduced.

[0062] The valve assembly 33 includes a stopper 33-1 that is slidably connected to the groove 32, and its surface is in contact with the through hole 31. An L-shaped plate 33-2 is slidably connected to the outer shell 12, and one end of the L-shaped plate is fixedly connected to the bottom of the stopper 33-1, and the other end of the L-shaped plate is slidably connected to the slide groove 34. A spring 33-3 is fixedly connected between the surface of the stopper 33-1 and the inner wall of the groove 32.

[0063] Through the setting of the sliding groove 34, when the driving sleeve 16 moves downward to open the fracturing inner hole 17, the L-shaped plate 33-2 will not be driven to move. After the anti-return sliding sleeve 15 is moved downward and reset, the driving sleeve 16 continues to move downward to drive the L-shaped plate 33-2 to move, driving the block 33-1 in the through hole 31 to move into the groove 32. While the driving sleeve 16 leaks the through hole 31, the block 33-1 opens the through hole 31. Through the setting of the spring piece 33-3, the block 33-1 is compressed and deformed after it moves downward, providing a force for resetting the block 33-1 and the L-shaped plate 33-2 after the driving sleeve 16 moves upward.

[0064] Example 4

[0065] Reference Figures 1 to 12 , which is the fourth embodiment of the present invention, and is based on the first three embodiments.

[0066] Specifically, the following control methods are also included:

[0067] In the initial state, the driving sleeve 16 and the anti-return sleeve 15 are both in the closed state, and no liquid flows between the inside and outside of the anti-return sleeve 15. The specific operation is as follows: the anti-return sleeve 15 is moved to the specified position along the cementing pipe string, and the driving sleeve 16 is moved downward and opened by the action of the sleeve switch tool. In this process, the limit unlocking mechanism 2 is driven, so that the block 21-3 on the limit assembly 21 realizes the preliminary unlocking of the anti-return sleeve 15, and the airbag 22-5 on the blocking assembly 22 is retracted into the anti-return sleeve 15;

[0068] The liquid passes through the fracturing inner hole 17 and reaches the chamber formed between the outer shell 12 and the connecting tube 13. As the pressure inside the chamber increases, the anti-return sleeve 15 drives the clamping block 21-3, causing the clamping block 21-3 to move into the round shell 21-2. The liquid inside the driving sleeve 16 pushes the anti-return sleeve 15 downward until the fracturing outer hole 18 is opened. The liquid inside the driving sleeve 16 is transferred to the outside of the device through the fracturing inner hole 17, the chamber, and the fracturing outer hole 18 in sequence. The pressure is transferred to the outside, establishing a communication channel between the ground and the fractured formation.

[0069] When the ground pump stops working or the formation pressure is higher than the pressure of the driving sleeve 16, the internal pressure of the anti-return sleeve 15 is reduced to the pre-pressure of the cylindrical coil spring 110. The cylindrical coil spring 110 pushes the anti-return sleeve 15 to close, blocking the connection between the inside of the device and the formation, preventing cement from flowing backward, and lifting the service tool. The switch tool drives the driving sleeve 16 to the closed position, achieving complete isolation between the formation and the inside of the pipe string.

[0070] In summary, the cementing check mechanism 1 can move the anti-return sleeve 15 upward and reset after the injection is completed. Compared with the existing technology, it avoids the reverse flow of cement, which leads to failure of interlayer isolation, reduced sealing of the cement ring, and even abnormal annular pressure, thereby improving the cementing effect and driving the sleeve 16 to be reset with the help of tools, thereby playing a secondary sealing role and avoiding reverse flow of cement.

[0071] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A self-locking cement check sleeve for one-trip half-stroke cementing, characterized by: include, A cementing check mechanism (1) comprises an upper joint (11), an outer shell (12) fixedly connected to the upper joint (11), a connecting cylinder (13) fixedly connected to the outer shell (12), a lower joint (14) fixedly connected to the lower end of the connecting cylinder (13), an anti-return sleeve (15) slidably connected between the outer shell (12) and the connecting cylinder (13), a driving sleeve (16) slidably connected inside the outer shell (12), a fracturing inner hole (17) opened on the surface of the outer shell (12), a fracturing outer hole (18) opened on the surface of the connecting cylinder (13), a connecting head (19) fixedly connected inside the lower joint (14), and a cylindrical coil spring (110) provided between the lower joint (14) and the anti-return sleeve (15).

2. The self-locking cement check sleeve for one-trip half-stroke cementing according to claim 1, characterized in that: A limit unlocking mechanism (2) is installed on the outer shell (12) and the anti-return sliding sleeve (15) and is arranged on the driving sliding sleeve (16). The limit unlocking mechanism (2) includes a limit assembly (21) installed on the outer shell (12). A blocking assembly (22) is installed on the outer shell (12) and the anti-return sliding sleeve (15) and is arranged on the limit assembly (21).

3. The self-locking cement check sleeve for one-trip half-stroke cementing according to claim 2, characterized in that: The limiting assembly (21) comprises a groove body (21-1) provided in the outer shell (12); a circular shell (21-2) is slidably connected in the groove body (21-1); a clamping block (21-3) is slidably connected on the outer shell (12); one end of the clamping block (21-3) passes through the circular shell (21-2) and is fixedly connected to a connecting block (21-4); a telescopic spring (21-5) is fixedly connected between the surface of the connecting block (21-4) and the inner wall of the circular shell (21-2); a clamping groove (21-6) matching the clamping block (21-3) is provided on the inner wall of the anti-return sliding sleeve (15); and the clamping block (21-3) is inserted into the clamping groove (21-6).

4. The self-locking cement check sleeve for one-trip half-stroke cementing according to claim 3, characterized in that: A short block (21-7) is fixedly connected to the surface of the circular shell (21-2), a short column (21-8) is fixedly connected to the connecting block (21-4), a limiting groove (21-9) is provided on the inner wall of the trough body (21-1), and a limiting block (21-10) is fixedly connected to the outer surface of the circular shell (21-2) and is slidably connected in the limiting groove (21-9).

5. The self-locking cement check sleeve for one-trip half-stroke cementing according to claim 4, characterized in that: The blocking component (22) comprises an air groove (22-1) opened in the outer shell (12); a guide plate (22-2) is slidably connected to the outer shell (12) and penetrates the air groove (22-1); a fixing block (22-3) is fixedly connected to the upper end of the guide plate (22-2) and is fixedly connected to the surface of the driving sleeve (16); a guide hole (22-8) is opened on the surface of the guide plate (22-2), and a short column (21-8) is slidably connected therein.

6. The self-locking cement check sleeve for one-trip half-stroke cementing according to claim 5, characterized in that: A piston (22-4) is slidably connected in the air groove (22-1) and is sleeved on the guide plate (22-2). An air bag (22-5) is embedded in the outer shell (12). A hose (22-6) is connected to the air bag (22-5). One end of the hose (22-6) passes through the outer shell (12) and is connected to the air groove (22-1). Adjacent air bags (22-5) are connected by a connecting pipe (22-7).

7. The self-locking cement check sleeve for one-trip half-stroke cementing according to claim 6, characterized in that: A sealing ring (22-9) is provided between the piston (22-4) and the air groove (22-1), and the sealing ring (22-9) is sleeved on the surface of the piston (22-4). A sealing sleeve (22-10) is provided between the guide plate (22-2) and the outer shell (12), and the sealing sleeve (22-10) is sleeved on the surface of the guide plate (22-2).

8. The self-locking cement check sleeve for one-trip half-stroke cementing according to claim 1, characterized in that: The outer shell (12) is provided with a reflux mechanism (3), comprising a through hole (31) and a groove (32) provided on the outer shell (12); a valve assembly (33) is provided in the through hole (31) and the groove (32); and a sliding groove (34) is provided on the outer surface of the driving sleeve (16), which cooperates with the valve assembly (33).

9. The self-locking cement check sleeve for one-trip half-stroke cementing according to claim 8, characterized in that: The valve assembly (33) includes a stopper (33-1) slidably connected to the groove (32), and its surface contacts the through hole (31); an L-shaped plate (33-2) is slidably connected to the outer shell (12), and one end of the L-shaped plate is fixedly connected to the bottom of the stopper (33-1), and the other end of the L-shaped plate is slidably connected to the slide groove (34); a spring (33-3) is fixedly connected between the surface of the stopper (33-1) and the inner wall of the groove (32).

10. A method for preventing backflow using a self-locking cement check sleeve for one-trip half-stroke cementing, characterized in that: The method comprises the self-locking cement check sleeve for one-trip half-stroke cementing according to any one of claims 1 to 9, and further comprises the following control method: In the initial state, the driving sleeve (16) and the anti-return sleeve (15) are both in a closed state, and no liquid flows between the inside and outside of the anti-return sleeve (15). The specific operation is as follows: the anti-return sleeve (15) is moved to a designated position along with the cementing pipe string, and the driving sleeve (16) is moved downward and opened by the action of the sleeve switch tool, and the limit unlocking mechanism (2) is driven in this process, so that the block (21-3) on the limit assembly (21) realizes the preliminary unlocking of the anti-return sleeve (15), and the air bag (22-5) on the blocking assembly (22) is contracted into the anti-return sleeve (15); The liquid reaches the chamber formed between the outer shell (12) and the connecting tube (13) through the fracturing inner hole (17). As the pressure inside the chamber increases, the anti-return sliding sleeve (15) drives the block (21-3), causing the block (21-3) to move into the round shell (21-2). The liquid inside the driving sliding sleeve (16) pushes the anti-return sliding sleeve (15) to move downward until the fracturing outer hole (18) is opened. The liquid inside the driving sliding sleeve (16) is sequentially transmitted through the fracturing inner hole (17), the chamber, and the fracturing outer hole (18) to the outside of the device. The pressure is transmitted to the outside, thereby establishing a communication channel between the ground and the fracturing formation. When the ground pump stops working or the formation pressure is higher than the pressure of the driving sleeve (16), the internal pressure of the anti-return sleeve (15) is reduced to the pre-pressure of the cylindrical coil spring (110), and the cylindrical coil spring (110) pushes the anti-return sleeve (15) to close, blocking the connection between the inside of the device and the formation, preventing cement from flowing in reverse, and lifting the service tool. The switch tool drives the driving sleeve (16) to the closed position, thereby achieving complete isolation between the formation and the inside of the pipe string.

Images