A high-temperature anti-flowback cementing sliding sleeve for cementing

Abstract

The application discloses a high-temperature anti-flowback cementing sliding sleeve for cementing, and solves the technical problem that the cementing sliding sleeve does not have the anti-flowback function. The device comprises a sliding sleeve main pipe, a sealing cylinder, an outer sheath, an annular cavity, a sliding sleeve hole, a circulating hole, an opening and closing sliding sleeve, an anti-flowback sliding sleeve and an elastic component. After the opening and closing sliding sleeve moves downward under the action of an external opening and closing tool, the sliding sleeve hole is aligned with the corresponding circulating hole, cement slurry is pumped into the sliding sleeve main pipe, the cement slurry enters the annular cavity through the sliding sleeve hole, and the anti-flowback sliding sleeve is driven to move downward, so that the sliding sleeve hole, the annular cavity and the circulating hole are communicated, the anti-flowback sliding sleeve moves upward under the action of the elastic component after the cement slurry stops being pumped, and the circulating hole is closed, so that the anti-flowback function is realized. The cementing sliding sleeve has the anti-flowback function, is resistant to high temperature, and can improve the operation convenience and working efficiency.

Description

Technical Field

[0001] This invention belongs to the field of cementing sand control technology, specifically relating to a high-temperature anti-backflow cementing sliding sleeve for cementing. Background Technology

[0002] Currently, in the existing side-drilled horizontal well cementing and sand control process, the construction process is as follows: the first run of the tubing string is cemented using a staged clamp cementing machine, then the staged clamp blind plate is removed, the production layer open hole is drilled, and finally the sand control tubing string is run in for gravel filling.

[0003] The existing cementing sleeves for side-drilled horizontal wells have the following disadvantages:

[0004] 1. Cementing is achieved by using staged clamping cement. After cementing is completed, blind plates need to be drilled out, which is cumbersome and has low working efficiency.

[0005] 2. The cementing sleeve only has opening and closing functions and lacks anti-backflow function;

[0006] 3. Cementing sleeves typically use ordinary rubber sealing structures, which are difficult to meet the sealing requirements of multiple cycles of high and low temperature and hot and cold changes of 350℃.

[0007] Therefore, providing a cementing sleeve that can prevent backflow, withstand high temperatures, and is easy to operate is of great significance for improving cementing performance. Summary of the Invention

[0008] In order to solve all or some of the above problems, the purpose of this invention is to provide a high-temperature anti-backflow cementing sleeve for cementing, which has anti-backflow function, high temperature resistance, and can also improve operation convenience and work efficiency.

[0009] This invention provides a high-temperature anti-backflow cementing sleeve for cementing, comprising:

[0010] The main sliding sleeve is used to connect to the tubing column;

[0011] A sealing cylinder is threadedly connected to the bottom of the sliding sleeve main tube;

[0012] An outer sheath is threaded onto the main sliding sleeve, and an annular cavity is formed between the main sliding sleeve and the outer sheath.

[0013] Multiple sliding sleeve holes are provided on the main sliding sleeve tube, and each of the multiple sliding sleeve holes communicates with the annular cavity.

[0014] Multiple circulation holes are provided on the outer sheath.

[0015] The switch sleeve is vertically slidably connected inside the main sleeve tube;

[0016] Anti-backflow sliding sleeve; vertically slidably disposed within the annular cavity;

[0017] An elastic component is disposed within the annular cavity and is used to push the anti-backflow sliding sleeve upward.

[0018] When the switch sleeve moves downward under the action of an external switching tool, the multiple sleeve holes communicate with the annular cavity, and cement slurry is pumped into the main sleeve. As the pressure of the cement slurry gradually increases, the cement slurry enters the annular cavity through the sleeve holes and pushes the anti-backflow sleeve downward, so that the sleeve holes, the annular cavity and the circulation hole are connected. When the cement slurry pumping stops, the anti-backflow sleeve moves upward under the action of the elastic component and closes the circulation hole to achieve the anti-backflow function.

[0019] Optionally, the anti-backflow sleeve includes:

[0020] The sliding sleeve body is slidably disposed within the annular cavity;

[0021] A stepped groove is provided on the inner side wall of the sliding sleeve body and aligned with the sliding sleeve hole;

[0022] An O-ring is fixedly embedded in the inner wall of the sliding sleeve body;

[0023] There are two retaining rings, which are fixedly embedded in the inner side wall of the sliding sleeve body and closely abut against the main sliding sleeve, and the O-ring (83) is located between the two retaining rings (84).

[0024] Optionally, the sliding sleeve main tube is threaded with a receiving ring located in the annular cavity, and an elastic sealing ring is fixedly connected to the bottom of the receiving ring. After the anti-backflow sliding sleeve moves upward under the action of the elastic component, the anti-backflow sliding sleeve abuts and seals with the sealing ring.

[0025] Optionally, the elastic component includes:

[0026] A support base is disposed between the main sliding sleeve and the outer sheath;

[0027] A return spring is disposed in the annular cavity and sleeved on the main slide sleeve. The top end of the return spring is connected to the anti-backflow slide sleeve, and the bottom end is connected to the support base.

[0028] Optionally, the support base includes a fixed ring and an adjusting ring. The fixed ring is disposed on the main slide sleeve, and the adjusting ring is threaded onto the fixed ring. The outer side wall of the adjusting ring is tightly fitted with the inner side wall of the outer sheath. The bottom end of the return spring abuts against the adjusting ring, and the adjusting ring can adjust the compression of the return spring to adjust the opening force of the anti-backflow slide sleeve.

[0029] Optionally, the switch sleeve includes:

[0030] The opening and closing sleeve is vertically slidably connected inside the main sliding sleeve tube and is used to control the opening and closing of the sliding sleeve hole;

[0031] There are two stepped sections, each located at a corresponding end of the opening and closing sleeve;

[0032] There are two locking claws, each threadedly connected to the corresponding stepped portion, and the spring-loaded opening claw of the external switching tool can hook and engage with the locking claw.

[0033] Each of the stepped portions is symmetrically provided with a pair of support rings, and the two locking claws abut against the corresponding support rings. Each pair of support rings is provided with a C-shaped metal sealing ring on the side that is close to each other. The arch surfaces of the two corresponding C-shaped metal sealing rings face each other and together seal the opening and closing sleeve and the sliding sleeve main pipe.

[0034] Optionally, the sliding sleeve main pipe is internally threaded with a limiting sleeve, which is located above the opening and closing sleeve and is used to restrict the opening and closing sleeve from sliding upward.

[0035] Optionally, the inner wall of the limiting sleeve is provided with a guide slope, and the elastic opening claw of the external switching tool can retract under the action of the guide slope and separate from the locking claw.

[0036] Optionally, the outer sheath and the sliding sleeve main pipe are sealed by a sealing O-ring.

[0037] Optionally, the sliding sleeve main pipe and the sealing cylinder are sealed by a graphite sealing ring.

[0038] As can be seen from the above technical solution, the high-temperature anti-backflow cementing sleeve for cementing provided by the present invention has the following advantages:

[0039] The anti-backflow sleeve in this device requires the switch sleeve to be in the open position, and the mud pressure inside the cementing sleeve must be higher than the external pressure, reaching a set pressure value, for the anti-backflow sleeve to open. When the pressure difference between the inside and outside of the cementing sleeve disappears or the external pressure exceeds its internal pressure, the anti-backflow sleeve can automatically close, thus achieving the anti-backflow function and preventing external solid particles or cement from entering the wellbore. Components such as the C-type metal sealing ring and the stone-ground sealing ring can meet the sealing requirements of high and low temperature alternating heat and cold at 350℃, enabling the cementing sleeve to withstand high temperatures and thus improving its operational stability. Furthermore, when this cementing sleeve is applied to the cementing sand control process tubing, there is no need to insert rubber plugs during cementing operations, and no need to drill out blind plates after cementing operations. The closure of the cementing sleeve can also be verified by annular pressurization. Cementing and gravel filling operations can be completed in one tubing run. Compared with traditional cementing sand control processes, the operation is more convenient, reducing the number of drilling trips, lowering operating costs, and improving work efficiency.

[0040] Other features and advantages of the present invention will be set forth in the following description. Attached Figure Description

[0041] The accompanying drawings are provided to further understand the technical solutions of the present invention and constitute a part of the specification. They are used together with the embodiments of the present invention to explain the technical solutions of the present invention, and do not constitute a limitation on the technical solutions of the present invention.

[0042] Figure 1 This is a schematic diagram of the overall structure of an embodiment of the present invention;

[0043] Figure 2 This is a cross-sectional view of an embodiment of the present invention, showing the structure for fixing the top position of the sliding sleeve;

[0044] Figure 3 This is a cross-sectional view of an embodiment of the present invention, showing the structure at the middle position of the cementing sleeve;

[0045] Figure 4 This is a cross-sectional view of the switch sleeve in an embodiment of the present invention.

[0046] Explanation of reference numerals in the attached figures:

[0047] 1. Main sliding sleeve; 2. Sealing cylinder; 3. Outer sheath; 4. Annular cavity; 5. Sliding sleeve hole; 6. Circulation hole; 7. Switch sliding sleeve; 71. Opening and closing sleeve; 72. Stepped part; 73. Locking claw; 74. Support ring; 75. C-shaped metal sealing ring; 8. Anti-backflow sliding sleeve; 81. Sliding sleeve body; 82. Step groove; 83. O-ring; 84. Retaining ring; 9. Elastic component; 91. Support seat; 911. Fixing ring; 912. Adjusting ring; 92. Return spring; 10. Receiving ring; 11. Sealing ring; 12. Limiting sleeve; 13. Locking groove; 14. Guide slope; 15. Sealing O-ring; 16. Graphite sealing ring. Detailed Implementation

[0048] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that, unless otherwise specified, the embodiments and features described in the embodiments of the present invention can be arbitrarily combined with each other.

[0049] like Figure 1 , Figure 2 , Figure 3 , Figure 4 The illustration shows an embodiment of the present invention, which discloses a high-temperature anti-backflow cementing sleeve for cementing. It includes a main sleeve 1 for connection to the tubing string, a sealing cylinder 2 at the bottom of the main sleeve 1, and the top end of the sealing cylinder 2 inserted into the main sleeve 1 and threadedly connected to it. An outer sheath 3 is fitted onto the main sleeve 1, the top end of which is threadedly connected to the main sleeve 1, and an annular cavity 4 is formed between the main sleeve 1 and the outer sheath 3.

[0050] In one embodiment, such as Figure 1 As shown, the main sliding sleeve 1 has multiple sliding sleeve holes 5, which are arranged at equal intervals along the circumference of the main sliding sleeve 1, and each of the multiple sliding sleeve holes 5 is connected to the annular cavity 4. The outer sheath 3 has multiple circulation holes 6, and the multiple circulation holes 6 are aligned with the multiple sliding sleeve holes 5 one by one.

[0051] In one embodiment, such as Figure 1 As shown, a switch sleeve 7 is vertically slidably connected inside the main sliding sleeve 1. When the switch sleeve 7 moves downward under the action of an external switching tool, it moves to below the sleeve hole 5, meaning it no longer closes the sleeve hole 5. At this time, the multiple sleeve holes 5 are connected to the annular cavity 4. Similarly, when the switch sleeve 7 moves upward under the action of an external switching tool, it can block and close the sleeve hole 5.

[0052] In one embodiment, such as Figure 1 As shown, an anti-backflow sleeve 8 is vertically slidably connected inside the annular cavity 4. When cement slurry is pumped into the main pipe 1 of the sleeve, and as the pressure of the cement slurry gradually increases, the cement slurry enters the annular cavity 4 through the sleeve hole 5. At this time, the cement slurry pushes the anti-backflow sleeve 8 downward. When the anti-backflow sleeve 8 moves to below the circulation hole 6, the sleeve hole 5, the annular cavity 4, and the circulation hole 6 are connected.

[0053] In one embodiment, such as Figure 1 As shown, an elastic component 9 is installed inside the annular cavity 4. The elastic component 9 pushes the anti-backflow sleeve 8 upward. When the cement slurry pumping stops, the anti-backflow sleeve 8 can move upward under the action of the elastic component 9 and close the circulation hole 6 to achieve the anti-backflow function.

[0054] In this embodiment, the anti-backflow sleeve 8 requires the switch sleeve 7 to be in the open state, and the mud pressure inside the cementing sleeve to be higher than the external pressure, reaching a set pressure value, before the anti-backflow sleeve 8 can open. When the pressure difference between the inside and outside of the cementing sleeve disappears or the external pressure is higher than its internal pressure, the anti-backflow sleeve 8 can automatically close, thereby realizing the anti-backflow function and preventing external solid particles or cement from entering the wellbore.

[0055] In one embodiment, such as Figure 1 , Figure 2 As shown, the anti-backflow sliding sleeve 8 includes a sliding sleeve body 81 that is vertically slidably connected in the annular cavity 4. The inner side wall of the sliding sleeve body 81 is provided with a stepped groove 82, and multiple sliding sleeve holes 5 are respectively connected to the stepped groove 82. That is, the mud can enter the stepped groove 82 through the sliding sleeve holes 5 and push the sliding sleeve body 81 to move downward.

[0056] In one embodiment, such as Figure 1 , Figure 2 As shown, an O-ring 83 is fixedly embedded in the inner wall of the sliding sleeve body 81. At the same time, two retaining rings 84 are fixedly embedded in the inner wall of the sliding sleeve body 81, and the two retaining rings 84 are respectively in close contact with the sliding sleeve main pipe 1. The O-ring 83 is located between the two retaining rings 84 to protect the O-ring 83 and prevent the O-ring from being squeezed and deformed under high pressure, thereby ensuring the reliability of the seal.

[0057] In one embodiment, such as Figure 1 , Figure 2 As shown, a receiving ring 10 is threaded onto the main sliding sleeve 1. The receiving ring 10 is located at the upper end inside the annular cavity 4, and an elastic sealing ring 11 is fixedly connected to the bottom of the receiving ring 10. When the sliding sleeve body 81 moves upward under the action of the elastic component 9, the top end of the sliding sleeve body 81 abuts against the sealing ring 11 to seal, thereby improving the sealing effect.

[0058] In one embodiment, such as Figure 1 , Figure 3 As shown, the elastic component 9 includes a support seat 91 disposed between the sliding sleeve main body 1 and the outer sheath 3. A return spring 92 is sleeved on the sliding sleeve main body 1 and is located in the annular cavity 4. At the same time, the top end of the return spring 92 is connected to the sliding sleeve body 81 and the bottom end is connected to the support seat 91, and is used to push the sliding sleeve body 81 to move upward.

[0059] In one embodiment, such as Figure 1 , Figure 3As shown, the support base 91 includes a fixed ring 911 and an adjusting ring 912. The fixed ring 911 is threadedly connected to the sliding sleeve main tube 1, and the adjusting ring 912 is threadedly sleeved on the fixed ring 911, with the outer side wall of the adjusting ring 912 tightly fitted against the inner side wall of the outer sheath 3. Simultaneously, the bottom end of the return spring 92 abuts against the adjusting ring 912. By adjusting the number of thread turns between the adjusting ring 912 and the fixed ring 911, the compression of the return spring 92 can be adjusted, thereby adjusting the opening force of the anti-backflow sliding sleeve 8.

[0060] The opening pressure of the anti-backflow sleeve 8 can be adjusted by adjusting ring 912. The greater the compression of the return spring 92, the greater the opening pressure of the anti-backflow sleeve 8; the less the compression of the return spring 92, the smaller the opening pressure of the anti-backflow sleeve 8.

[0061] In one embodiment, such as Figure 1 , Figure 4 As shown, the switch sleeve 7 includes an opening / closing sleeve 71 vertically slidably connected within the main sleeve tube 1, and the opening / closing sleeve 71 is used to control the opening and closing of the sleeve hole 5. Stepped portions 72 are integrally formed at both ends of the opening / closing sleeve 71, and locking claws 73 are threaded onto each of the two stepped portions 72. The spring-loaded opening claw of an external switching tool can engage with the locking claws 73, allowing the external switching tool to drive the opening / closing sleeve 71 to slide vertically, thereby achieving the opening and closing control of the sleeve hole 5.

[0062] In one embodiment, such as Figure 1 , Figure 4 As shown, each step 72 is fitted with a pair of support rings 74, which are symmetrically arranged, and two locking claws 73 abut against the corresponding support rings 74. Simultaneously, a C-shaped metal sealing ring 75 is fitted on the side of each pair of support rings 74 that is close to each other. The arched surfaces of the two corresponding C-shaped metal sealing rings 75 face each other, and the C-shaped metal sealing rings 75 abut against the step 72 and the sliding sleeve main pipe 1, thereby achieving a seal between the opening / closing sleeve 71 and the sliding sleeve main pipe 1, meeting the sealing requirements under alternating high and low temperatures of 350℃.

[0063] In one embodiment, such as Figure 2 , Figure 4 As shown, the sliding sleeve main tube 1 is internally threaded with a limiting sleeve 12. The limiting sleeve 12 is located above the opening and closing sleeve 71 and is used to restrict the upward sliding of the opening and closing sleeve 71. That is, when the external switching tool drives the opening and closing sleeve 71 to move upward and abuts against the limiting sleeve 12, the opening and closing sleeve 71 closes the sliding sleeve hole 5. At the same time, the inner wall of the limiting sleeve 12 is provided with a locking groove 13, and the ratchet on the locking claw 73 can cooperate with the locking groove 13 to lock.

[0064] In one embodiment, such as Figure 2 , Figure 4 As shown, the inner wall of the limiting sleeve 12 is provided with a guide slope 14. When the opening and closing sleeve 71 abuts against the limiting sleeve 12, the elastic switch claw on the external switching tool retracts under the action of the guide slope 14, and separates the elastic switch claw from the locking claw 73, thereby realizing the smooth release of the opening and closing sleeve 71. At the same time, the ratchet on the locking claw 73 engages in the locking groove 13 to realize the stable closing of the opening and closing sleeve 71.

[0065] In one embodiment, such as Figure 1 , Figure 2 As shown, the outer sheath 3 and the sliding main tube 1 are sealed by a sealing O-ring 15. That is, the sealing O-ring 15 is fixedly embedded on the sliding main tube 1, and the sealing O-ring 15 is tightly abutted against the inner side wall of the outer sheath to ensure the seal between the outer sheath 3 and the sliding main tube 1.

[0066] In one embodiment, such as Figure 1 , Figure 3 As shown, the sliding sleeve main pipe 1 and the sealing cylinder 2 are sealed by a graphite sealing ring 16. Specifically, the outer wall of the sealing cylinder 2 is inlaid with a graphite sealing ring 16, and the graphite sealing ring 16 tightly abuts against the inner wall of the sliding sleeve main pipe 1 to achieve the sealing requirement under alternating high and low temperatures of 350℃. In this embodiment, the sealing cylinder 2 can cooperate with the sealing module pre-installed on the cementing string to achieve wellbore sealing below the sealing cylinder 2, preventing residual cement from entering the lower wellbore and effectively preventing cementing string jamming.

[0067] As described above, this device has an anti-backflow function, which can effectively prevent high-sealing cement slurry from backflowing into the wellbore. The C-type metal sealing ring and the graphite sealing ring 16 enable the device to meet the sealing requirements of subsequent high-temperature gas injection at 350℃ under alternating high and low temperatures. At the same time, the compression of the return spring 92 can be adjusted, allowing the opening pressure of the anti-backflow sleeve 8 to be adjusted.

[0068] Furthermore, when this cementing sleeve is applied to the cementing sand control process string, there is no need to insert rubber plugs during cementing operations, and there is no need to drill out blind plates after cementing operations. The closure of the cementing sleeve can also be verified by pressurizing the annulus. Cementing and gravel filling operations can be completed in one trip of the string. Compared with the traditional cementing sand control process, the operation is more convenient, the number of drilling trips is reduced, the operating cost is reduced, and the work efficiency is improved.

[0069] It should be noted that, unless otherwise stated, the technical or scientific terms used in this invention should have the ordinary meaning as understood by one of ordinary skill in the art.

[0070] Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly defined.

[0071] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. The present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A high-temperature anti-backflow cementing sleeve for well cementing, characterized in that, include: Sliding main pipe (1), used for connection with the pipe column; The sealing cylinder (2) is threadedly connected to the bottom of the sliding sleeve main tube (1); The outer sheath (3) is threaded onto the sliding sleeve main tube (1), and an annular cavity (4) is formed between the sliding sleeve main tube (1) and the outer sheath (3); Multiple sliding sleeve holes (5) are provided on the main sliding sleeve tube (1), and the multiple sliding sleeve holes (5) are respectively connected to the annular cavity (4); Multiple circulation holes (6) are provided on the outer sheath (3), and the multiple circulation holes (6) are aligned with the multiple sliding sleeve holes (5). The switch sleeve (7) is vertically slidably connected inside the main sleeve tube (1); Anti-backflow sliding sleeve (8); vertically slidably disposed within the annular cavity (4); The elastic component (9) is disposed in the annular cavity (4) and is used to push the anti-backflow sleeve (8) upward; When the switch sleeve (7) moves downward under the action of the external switch tool, the multiple sleeve holes (5) are connected to the annular cavity (4) respectively, and cement slurry is pumped into the sleeve main pipe (1). As the pressure of the cement slurry gradually increases, the cement slurry enters the annular cavity (4) through the sleeve holes (5) and pushes the anti-backflow sleeve (8) downward so that the sleeve holes (5), the annular cavity (4) and the circulation hole (6) are connected. When the cement slurry stops pumping, the anti-backflow sleeve (8) moves upward under the action of the elastic component (9) and closes the circulation hole (6) to achieve the anti-backflow function. The switch sleeve (7) includes: The opening and closing sleeve (71) is vertically slidably connected inside the sliding sleeve main tube (1) and is used to control the opening and closing of the sliding sleeve hole (5); There are two stepped sections (72), which are respectively provided at the corresponding ends of the opening and closing sleeve (71); There are two locking claws (73), which are threadedly connected to the corresponding step portion (72) respectively. The spring-loaded opening claw of the external switching tool can hook and cooperate with the locking claw (73). Each of the stepped portions (72) is symmetrically provided with a pair of support rings (74), and the two locking claws (73) abut against the corresponding support rings (74). Each pair of support rings (74) is provided with a C-shaped metal sealing ring (75) on the side that is close to each other. The arch surfaces of the two corresponding C-shaped metal sealing rings (75) face each other and jointly seal the opening and closing sleeve (71) and the sliding sleeve main tube (1). The sliding sleeve main tube (1) is internally threaded to a limiting sleeve (12), which is located above the opening and closing sleeve (71) and is used to restrict the opening and closing sleeve (71) from sliding upward. The inner wall of the limiting sleeve (12) is provided with a guide slope (14), and the elastic opening claw of the external switching tool can retract under the action of the guide slope (14) and separate from the locking claw (73).

2. The high-temperature anti-backflow cementing sleeve for cementing according to claim 1, characterized in that, The anti-backflow sleeve (8) includes: The sliding sleeve body (81) is slidably disposed within the annular cavity (4); A stepped groove (82) is provided on the inner side wall of the sliding sleeve body (81) and aligned with the sliding sleeve hole (5); O-ring (83) is fixedly embedded in the inner wall of the sliding sleeve body (81); There are two retaining rings (84), which are fixedly embedded in the inner sidewall of the sliding sleeve body (81) and closely abut against the sliding sleeve main tube (1), and the O-ring (83) is located between the two retaining rings (84).

3. The high-temperature anti-backflow cementing sleeve for cementing according to claim 1, characterized in that, The sliding sleeve main tube (1) is threaded with a receiving ring (10) located in the annular cavity (4). The bottom of the receiving ring (10) is fixedly connected with an elastic sealing ring (11). After the anti-backflow sliding sleeve (8) moves upward under the action of the elastic component (9), the anti-backflow sliding sleeve (8) and the sealing ring (11) abut and seal.

4. The high-temperature anti-backflow cementing sleeve for cementing according to claim 1, characterized in that, The elastic component (9) includes: A support base (91) is disposed between the sliding sleeve main tube (1) and the outer sheath (3); A return spring (92) is disposed in the annular cavity (4) and sleeved on the sliding sleeve main tube (1). The top end of the return spring (92) is connected to the anti-backflow sliding sleeve (8) and the bottom end is connected to the support base (91).

5. The high-temperature anti-backflow cementing sleeve for cementing according to claim 4, characterized in that, The support base (91) includes a fixed ring (911) and an adjusting ring (912). The fixed ring (911) is disposed on the sliding sleeve main tube (1). The adjusting ring (912) is threaded onto the fixed ring (911). The outer side wall of the adjusting ring (912) is tightly fitted with the inner side wall of the outer sleeve (3). The bottom end of the return spring (92) abuts against the adjusting ring (912). The adjusting ring (912) can adjust the compression of the return spring (92) to adjust the opening force of the anti-backflow sliding sleeve (8).

6. The high-temperature anti-backflow cementing sleeve for cementing according to claim 1, characterized in that, The outer sheath (3) and the sliding main tube (1) are sealed by a sealing O-ring (15).

7. The high-temperature anti-backflow cementing sleeve for cementing according to claim 1, characterized in that, The sliding sleeve main tube (1) and the sealing cylinder (2) are sealed by a graphite sealing ring (16).

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