Sealing bushing releasing mechanism, drilling liner hanger and releasing method

Abstract

The invention provides a sealing bushing releasing mechanism, a drilling liner hanger and a releasing method. The sealing bushing releasing mechanism comprises a sealing elastic claw, a limiting sleeve and a cone body, the cone body is communicated with a hanger body, an insertion pipe is located between the cone body and the hanger body, and an annular space exists between the insertion pipe and the cone body and between the insertion pipe and the hanger body; a liquid transfer hole is formed in the insertion tube; the insertion pipe is sleeved with the sealing elastic claw, and the sealing elastic claw is of an annular structure and has certain elasticity. An annular groove is formed in the inner wall of the cone body, and the sealing elastic claw is located in the annular groove. The limiting sleeve is positioned at the upper end of the sealing elastic claw; a reducing section is arranged on the insertion pipe, and when the reducing section reaches the position of the sealing elastic claw, the sealing elastic claw shrinks towards the insertion pipe under the action of self elasticity and is separated from the annular groove. The drilling liner hanger comprises the sealing bushing releasing mechanism. The releasing method is realized by using the drilling liner hanger. The method has the beneficial effect that the operation risk can be reduced.

Description

Technical Field

[0001] This invention relates to the field of downhole tool manufacturing technology in the oil and gas industry, specifically to a sealing core release mechanism, a tailpipe hanger, and a release method. Background Technology

[0002] Tailpipe cementing is a crucial method for cementing deep and complex wells. The tailpipe hanger is a cementing tool used in the cementing process. Currently used tailpipe hangers leave some parts, such as the sealing box and casing plug, inside the hanger after cementing. After drilling out, this can create cavities and steps inside the hanger, affecting subsequent operations. Furthermore, prolonged drilling inside the hanger can damage the bonding quality between the cement sheath and the casing in the overlapping section. While the sealing box structure used in current tailpipe hangers is simple and highly reliable, it also increases drilling cycles and may leave residues after drilling, affecting the subsequent borehole diameter. Current full-bore solutions used domestically and internationally have the following main technical defects: 1. The current lock-block-guide rail type sealing box structure is complex, requiring a large radial design space, and its performance is unstable in downhole environments. 2. Small pads in the gaps between the lock-block-guide rail type sealing box body and the insertion pipe, as well as between the slider and the sealing box body, can cause the lock block to jam, making tripping difficult. 3. The slider cavity between the keel hanger body and the sealing box is an annular groove, and there is no circumferential limiting for the slider. If the sealing core is abnormally left in the well, subsequent drilling and refining will be very difficult. Therefore, it is necessary to design a keel hanger and a release method that can overcome the above problems and achieve full-bore operation.

[0003] Chinese invention patent CN102587852A, entitled "A Tailpipe Hanger and Setting Tool," discloses a tailpipe hanger and setting tool with high pressure resistance, capable of setting and releasing the tube in a single operation without rotating the tubing string. It is suitable for use in various environments, including shallow wells, deep wells, highly deviated wells, and horizontal wells. However, this invention fails to consider the technical problems of current tailpipe hangers, such as the residue remaining after full-bore drilling and sealing, and the difficulty in handling these residues, which can affect subsequent operations. Summary of the Invention

[0004] The purpose of this invention is to address at least one of the aforementioned shortcomings of the prior art. For example, one objective of this invention is to provide a simple sealing core release mechanism that can prevent "locking" from occurring. Another objective is to provide a tailpipe hanger that can reduce operational risks. Yet another objective is to provide an efficient release method.

[0005] To achieve the above objectives, the present invention provides a sealing core release mechanism, which includes a sealing claw, a limiting sleeve, and a cone-shaped body. The cone-shaped body is connected to the hanger body, and an insertion tube is located between the cone-shaped body and the hanger body. An annular space exists between the insertion tube, the cone-shaped body, and the hanger body. The insertion tube has a fluid transmission hole, through which drilling fluid can flow from the annular space to the insertion tube. The sealing claw is sleeved on the insertion tube and has a ring structure with a certain degree of elasticity. The inner wall of the cone-shaped body has discontinuous annular grooves evenly distributed around its circumference, and the sealing claw is located in the annular grooves. The limiting sleeve is located at the upper end of the sealing claw and restricts the upward movement of the sealing claw under force during construction. The insertion tube has a reduced diameter section. When the reduced diameter section reaches the position of the sealing claw, the sealing claw retracts into the insertion tube under its own elastic force and disengages from the annular groove.

[0006] According to one or more exemplary embodiments of one aspect of the present invention, the upper end of the annular groove may be provided as a conical chamfered structure, and the lower end may be provided as a plateau step.

[0007] According to one or more exemplary embodiments of one aspect of the present invention, a safety connector may be provided at the lower end of the reduced diameter section of the insertion tube.

[0008] According to one or more exemplary embodiments of one aspect of the present invention, the safety connector can be connected to the insertion tube via a scissor pin.

[0009] According to one or more exemplary embodiments of one aspect of the present invention, the bottom end of the insertion tube may be provided with a tail tube rubber plug.

[0010] According to one or more exemplary embodiments of one aspect of the present invention, the radial distance between the sealing claw and the reduced diameter section may be greater than the depth of the annular groove.

[0011] According to one or more exemplary embodiments of one aspect of the present invention, the surface of the insertion tube may be treated with a Teflon process.

[0012] Another aspect of the present invention provides a full-bore tailpipe hanger, which may include an inner structure and an outer structure. The inner structure may include a feeding mechanism and a sealing core release mechanism as described above, which are connected sequentially from top to bottom. The outer structure may include a reconnection mechanism and a mounting mechanism, which are connected sequentially from top to bottom.

[0013] Another aspect of the present invention provides a release method, which can be implemented by the full-bore hanger as described above, and the release method may include the following steps: during field operation, the insertion tube moves upward, and when the reduced diameter section of the insertion tube moves upward to the position of the sealing spring claw, the sealing spring claw retracts due to its own elasticity and disengages from the annular groove of the cone body; if the sealing spring claw fails to retract normally during the upward movement of the insertion tube, the insertion tube continues to move upward, the safety joint forcibly retracts the spring claw, the annular groove and the sealing spring claw are forcibly engaged, assisting the sealing spring claw to retract, thereby releasing the hand.

[0014] According to one or more exemplary embodiments of another aspect of the present invention, if a foreign object is attached to the insertion tube during the upward process, the insertion tube can be rotated and the sealing claw scrapes off the attached object.

[0015] Compared with the prior art, the beneficial effects of the present invention include at least one of the following:

[0016] (1) The sealing core release mechanism provided by the present invention can ensure that the force direction of the sealing claw is always parallel to the axial direction of the pipe column during the entire construction process, and will not generate radial force, causing the claw to "lock" into the pipe.

[0017] (2) The outer surface of the insertion tube in the sealing core release mechanism provided by the present invention has been treated with Teflon, which greatly improves its surface smoothness and anti-adhesion performance.

[0018] (3) The limiting sleeve in the full-bore tailpipe hanger provided by the present invention can restrict the sealing claw from being forced upward during construction, and prevent the claw from contacting the upper conical surface of the discontinuous groove of the body and being subjected to radial force.

[0019] (4) The release method provided by the present invention will not leave any parts inside the hanger after the tailpipe rubber plug is released, achieving full bore. Compared with conventional tailpipe hangers, it can save drilling time in the later stage and reduce the risk of later operation.

[0020] (5) The method of dropping the plug provided by the present invention reduces the drilling cycle and leaves no residue after drilling. Attached Figure Description

[0021] The above and other objects and / or features of the present invention will become clearer from the following description taken in conjunction with the accompanying drawings, in which:

[0022] Figure 1a A schematic diagram of the sealing release mechanism in the construction state is shown as an exemplary embodiment of the present invention;

[0023] Figure 1b A schematic diagram of the sealing release mechanism in the drilling state, according to an exemplary embodiment of the present invention, is shown.

[0024] Figure 2a A schematic diagram of the structure of the sealing claw under reset force in an exemplary embodiment of the present invention is shown;

[0025] Figure 2b A schematic diagram of a sealing claw scraping off padding material is shown in an exemplary embodiment of the present invention;

[0026] Figure 3 A schematic diagram of a sealing spring claw structure of an exemplary embodiment of the present invention is shown;

[0027] Figure 4 A schematic diagram of a tailpipe plug structure of an exemplary embodiment of the present invention is shown;

[0028] Figure 5 A schematic diagram of a fluid transfer hole structure according to an exemplary embodiment of the present invention is shown.

[0029] Explanation of key figure labels:

[0030] 1-Pelvic body, 2-Insert tube, 21-Liquid transfer hole, 22-Annular groove, 231 First-stage reduced diameter section, 232-Second-stage reduced diameter section, 24-Safety connector, 241-Scissors pin, 25-Tail tube rubber plug, 3-Limit sleeve, 4-Suspension body, 5-Sealing spring claw, 51-Chamfered conical surface, 52-Right angle chamfer. Detailed Implementation

[0031] In the following description, a sealing core release mechanism, tailpipe hanger, and release method of the present invention will be explained in detail with reference to exemplary embodiments.

[0032] In the description of this application, it should be understood that the terms "upper," "lower," "left," "right," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. In the description of this invention, unless otherwise stated, "a plurality of" or "several" means two or more. In the description of this application, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "fixing" should be interpreted broadly. For example, it can refer to a fixed connection, a detachable connection, or an integral connection; it can refer to a direct connection or an indirect connection through an intermediate medium; it can refer to the internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in this invention can be understood according to the specific circumstances.

[0033] First exemplary embodiment

[0034] This exemplary embodiment provides a sealing core release mechanism.

[0035] Figure 1a A schematic diagram of the sealing release mechanism in the construction state is shown as an exemplary embodiment of the present invention; Figure 1b A schematic diagram of the sealing release mechanism in the drilling state, according to an exemplary embodiment of the present invention, is shown. Figure 3 A schematic diagram of a sealing spring claw structure of an exemplary embodiment of the present invention is shown; Figure 4 A schematic diagram of a tailpipe plug structure of an exemplary embodiment of the present invention is shown; Figure 5 A schematic diagram of a fluid transfer orifice structure of an exemplary embodiment of the present invention is shown below. Figures 1a-1b and Figures 3-5 This exemplary embodiment describes the sealing core release mechanism. It should be noted that the top-to-bottom direction described in the specification refers to... Figures 1a-1b and Figures 3-5 The direction from left to right in the middle.

[0036] In this exemplary embodiment, as Figure 1a As shown, the sealing core release mechanism mainly includes a sealing claw 5, a limiting sleeve 3, and a cone body 1.

[0037] The vertebral body 1 is connected to the suspension body 4, and the insertion tube 2 is located between the inner walls of the vertebral body 1 and the suspension body 4. An annular space exists between the insertion tube 2 and the vertebral body 1 and the suspension body 4. Figure 5 As shown, the insertion tube 2 is provided with a fluid transfer hole 21, through which drilling fluid can flow from the annular space outside the insertion tube 2 to the insertion tube 2; as Figure 1a As shown, the sealing claw 5 is sleeved on the insertion tube 2, and the insertion tube 2 expands the sealing claw 5. Figure 3 As shown, the sealing spring claw is a ring-shaped structure with a certain degree of elasticity. The sealing spring claw has evenly distributed spring claws along its circumference. An enlarged-diameter step is provided on the lower outer wall of the spring claw. This enlarged-diameter step mates with the ring-shaped groove on the inner wall of the cone-shaped body. The upper end of the enlarged-diameter step is a conical chamfer 51, and the lower end is a right-angle chamfer 52. Figure 1aAs shown, the inner wall of the cone body 1 has an annular groove 22 to axially limit the sealing claw 5. The sealing claw 5 is located in the annular groove 22. The upper end of the annular groove 22 is a conical chamfered structure, and the lower end is a platform step. This structure can cooperate with the expanded diameter step structure of the sealing claw to limit the lower end of the sealing claw. The limiting sleeve 3 is located at the upper end of the sealing claw 5, that is, the sealing claw 5 is set between the lower end of the limiting sleeve 3 and the inner wall of the cone body 1 and the outer wall of the insertion tube 2. The limiting sleeve 3 restricts the sealing claw 5 from moving upward under force during construction. Thus, the upper end of the sealing claw 5 is limited by the limiting sleeve 3, and the lower end is limited by the annular groove 22 of the cone body 1, ensuring that the force direction of the sealing claw is always parallel to the axial direction of the insertion tube during the entire construction process, and no radial component force is generated, avoiding the situation where the sealing claw "locks up" the insertion tube.

[0038] Specifically, during well circulation or cementing operations, the sealing claw experiences upward force, meaning the force direction is the upward movement direction of the sealing claw. At this time, the limiting sleeve restricts the upper surface of the sealing claw, resulting in no contact or force between the claw and the cone surface of the body. No additional force is generated between the claw and the insertion pipe. Therefore, the claw and the insertion pipe experience light pressure sliding, preventing "locking up." Furthermore, during reverse pressure tripping, the sealing claw experiences downward force, meaning the force direction is the downward movement direction of the sealing claw. At this time, the claw is limited by the lower platform step of the body groove, and the force direction is axial, with no radial component. Again, there is no additional force between the claw and the insertion pipe, preventing the claw from "locking up" the insertion pipe.

[0039] The insertion tube has a reduced diameter section. When the reduced diameter section reaches the sealing spring claw position, the sealing spring claw retracts into the insertion tube under its own elastic force, disengaging from the annular groove. Specifically, such as... Figure 1b As shown, the reduced diameter section may include a first-stage reduced diameter section 231 and a second-stage reduced diameter section 232, with the first-stage reduced diameter section 231 positioned above the second-stage reduced diameter section 232. The outer diameter of the first-stage reduced diameter section 231 is larger than the outer diameter of the second-stage reduced diameter section 232. When the first-stage reduced diameter section 231 aligns with the sealing claw 5, the annular space between the upper and lower ends of the sealing claw 5 is connected, thus preventing the sealing claw from experiencing axial force due to a pressure difference between the upper and lower ends. If the sealing claw 5 is subjected to axial downward force, the elastic contraction of the sealing claw 5 itself will be limited by the frictional force of the right-angle chamfer structure at the lower end of the enlarged diameter step of the sealing claw 5, i.e., limited by the right-angle chamfer structure.

[0040] In this exemplary embodiment, as Figure 1bAs shown, a safety connector 24 can be provided at the lower end of the reduced-diameter section of the insertion tube. The upper inner wall of the safety connector 24 is a conical structure that matches the chamfer of the conical surface of the sealing spring claw. Here, the safety connector 24 can be located below the second-stage reduced-diameter section 232 of the insertion tube. When the insertion tube moves upward, the safety connector 24 can force contraction, providing an upward component force to cause the sealing spring claw 5 to contract towards the insertion tube. Generally, the pressure below the sealing spring claw 5 is higher than the pressure above it, causing the sealing spring claw 5 to move upward. However, there are also cases where the pressure above the sealing spring claw 5 is higher than the pressure below it. In this case, the sealing spring claw 5 tends to move downward, and the frictional force on the lower end face of the sealing spring claw 5 is greater. The second-stage reduced-diameter section 232 can provide space for the sealing spring claw 5 to retract. Of course, the present invention can also only provide a single-stage reduced-diameter section, connecting the annular space at the upper and lower ends of the sealing spring claw while providing space for the sealing spring claw to retract. However, considering factors such as the force on the sealing spring claw, a two-stage reduced-diameter structure is more reliable.

[0041] In this exemplary embodiment, as Figure 1b As shown, the safety connector 24 can be fixed to the lower end of the reduced diameter section of the insertion tube by setting a shear pin 241.

[0042] In this exemplary embodiment, as Figure 4 As shown, the bottom end of the insertion tube 2 may be provided with a tailpipe plug 25. Compared with the design of conventional tailpipe hangers, the tailpipe plug 25 here is directly fixed to the bottom end of the insertion tube 2. During the cementing process, after the tailpipe plug 25 is released, no parts remain inside the hanger, and full bore can be achieved.

[0043] In this exemplary embodiment, the surface of the insert tube can be treated with Teflon, which greatly improves its surface smoothness and enhances its anti-adhesion properties. This reduces the likelihood of gaskets adhering to the insert tube and affecting the resetting of the sealing spring.

[0044] In this exemplary embodiment, the sealing core release mechanism further includes a reverse-threaded sliding shaft and a functional threaded sleeve. The tailpipe hanger can achieve forward and reverse separation from the drill pipe via the reverse-threaded sliding shaft and the functional threaded sleeve.

[0045] Second exemplary embodiment

[0046] This exemplary embodiment provides a full-bore tailpipe hanger.

[0047] In this exemplary embodiment, the full-bore tailpipe hanger mainly includes an inner structure and an outer structure. The inner structure may include, from top to bottom, a feeding mechanism and a sealing core release mechanism as described in the first exemplary embodiment. The outer structure may include, from top to bottom, a reconnection mechanism and a mounting mechanism.

[0048] Third Exemplary Example

[0049] This exemplary embodiment provides a method for dropping hands.

[0050] Figure 2a A schematic diagram of the structure of the sealing claw under reset force in an exemplary embodiment of the present invention is shown; Figure 2b A schematic diagram of a sealing claw scraping off padding material, representing an exemplary embodiment of the present invention, is shown below. Figures 2a-2b This describes the method of dropping hands in this exemplary embodiment. It should be noted that the top-to-bottom direction described in the specification is... Figures 2a-2b The direction from left to right in the middle.

[0051] In this exemplary embodiment, the release method can be implemented using the full-bore tailpipe hanger described in the second exemplary embodiment above, and the release method mainly includes the following steps:

[0052] During on-site operation, the lifting and feeding mechanism moves the insertion tube upwards. When the reduced-diameter section of the insertion tube reaches the sealing claw position, the sealing claw retracts elastically, disengaging from the annular groove of the cone body. If any abnormality occurs during the upward movement of the insertion tube, causing the sealing claw to fail to retract normally, the insertion tube continues to move upwards. The safety joint forcibly retracts the claw, and the annular groove engages with the sealing claw, assisting in the retraction of the sealing claw and allowing it to be released, thus separating the sealing claw from the tailpipe hanger. As one embodiment of the invention, such as... Figure 2a As shown, when the reduced-diameter section of the insertion tube 2 ascends to the position of the sealing claw 5, the claw retracts inward under its own elastic force, disengaging from the annular groove 22, and the insertion tube 2 continues to ascend. The force F1 exerted by the safety connector 24 on the chamfered conical surface of the sealing claw and the reaction force F2 exerted by the chamfered conical surface of the annular groove 22 on the sealing claw 5 both cause the sealing claw 5 to retract inward. The gap H between the sealing claw 5 and the insertion tube 2 is much larger than the depth h of the annular groove 22. When an abnormal situation is encountered, the sealing claw 5 has enough space to retract to disengage from the annular groove 22 and be carried out by the safety connector 24.

[0053] In this exemplary embodiment, as Figure 2b As shown, if foreign objects become stuck in the insertion tube 2 during the upward movement of the insertion tube 2, the drill bit can be rotated to scrape and unblock the sealing claw 5.

[0054] In summary, the advantages of the present invention may include at least one of the following:

[0055] (1) The sealing core release mechanism provided by the present invention adopts the elasticity of its own material as the release power source through the improvement of the sealing core structure, which greatly reduces the structural complexity, increases the reliability of release, and avoids the risk of release failure due to the elastic block being unable to reset caused by solid particles or other reasons.

[0056] (2) The sealing core release mechanism provided by the present invention has added a limiting sleeve to limit the sealing spring claw axially, which can effectively prevent the sealing spring claw from "locking up" and inserting into the tube due to the pressure difference between the upper and lower parts.

[0057] (3) The full-bore tailpipe hanger provided by the present invention adds an annular groove to limit the circumferential positioning of the sealing claw. When the sealing claw cannot be lifted normally due to the padding problem, the strong padding problem can be dealt with by lifting and rotating the drill string. It can also significantly reduce the processing cycle when the sealing claw is abnormally left in the well for special grinding shoes.

[0058] (4) The upper end of the annular groove in the sealing core release mechanism provided by the present invention is a conical surface and the lower end is a plane. The discontinuity of the groove can restrict the circumferential rotation of the sealing claw. The lower plane of the groove can prevent the sealing claw from generating radial "clamping force" when pressing and pulling the drill. The upper conical surface of the groove can force the claw to contract when pulling the drill.

[0059] (5) The tailpipe plug in the full-bore tailpipe hanger provided by the present invention is installed at the lower end of the insertion tube. Compared with the conventional tailpipe hanger, it reduces a pair of threaded connections, which improves the safety of the tube string to a certain extent. After the tailpipe plug is released, no parts remain inside the hanger, thus achieving full bore.

[0060] (6) The lower end of the insertion tube in the full-bore tailpipe hanger provided by the present invention can be designed as a two-stage diameter reduction structure, which can provide space for the retraction of the spring claw.

[0061] (7) The full-bore tailpipe hanger provided by the present invention has a fluid transmission hole designed at the lower end of the insertion pipe to avoid a closed loop space in the annular space between the insertion pipe and the hanger body when the tailpipe is dropped and sent into the drill bit for verification.

[0062] (8) The method of discarding the casing provided by the present invention can avoid the later drilling and grinding, protect the casing, and improve the cementing quality of the overlapping section.

[0063] Although a sealing core release mechanism, tailpipe hanger, and release method of the present invention have been described above in conjunction with exemplary embodiments, those skilled in the art should understand that various modifications and changes can be made to the exemplary embodiments of the present invention without departing from the spirit and scope defined by the claims.

Claims

1. A sealing core release mechanism, characterized in that, The sealing and core release mechanism includes a sealing claw, a limiting sleeve, and a cone-shaped body. The cone body is connected to the suspension body, and the insertion tube is located between the cone body and the suspension body. There is an annular space between the insertion tube, the cone body, and the suspension body. The insertion tube is equipped with a fluid transmission hole, through which drilling fluid can flow from the annular space to the insertion tube. The sealing claw is sleeved on the insertion tube. The sealing claw has a ring structure and is elastic. The inner wall of the vertebral body is uniformly provided with discontinuous annular grooves, and the sealing claw is located in the annular grooves; The limiting sleeve is located at the upper end of the sealing spring claw, and the limiting sleeve restricts the sealing spring claw from moving upward under force during construction; The insertion tube has a reduced diameter section. When the reduced diameter section reaches the position of the sealing spring claw, the sealing spring claw retracts into the insertion tube under its own elastic force and disengages from the annular groove.

2. The sealing and repair core release mechanism according to claim 1, characterized in that, The upper end of the annular groove is designed with a chamfered conical surface, and the lower end is designed with a platform step.

3. The sealing core release mechanism according to claim 1, characterized in that, The lower end of the reduced-diameter section of the insertion tube is equipped with a safety connector.

4. The sealing core release mechanism according to claim 3, characterized in that, The safety connector is connected to the insertion tube via a shear pin.

5. The sealing core release mechanism according to claim 1, characterized in that, The bottom end of the insertion tube is provided with a tail tube rubber plug.

6. The sealing core release mechanism according to claim 1, characterized in that, The radial distance between the sealing claw and the reduced diameter section is greater than the depth of the annular groove.

7. The sealing core release mechanism according to claim 1, characterized in that, The surface of the insertion tube is treated with Teflon.

8. A full-bore tailpipe hanger, characterized in that, The full-bore tailpipe hanger comprises an inner structure and an outer structure, wherein... The inner structure includes a feeding mechanism and a sealing core release mechanism as described in any one of claims 1 to 7, connected sequentially from top to bottom; The outer structure includes a reconnection mechanism and a mounting mechanism connected sequentially from top to bottom.

9. A method of dropping one's hand, characterized in that, The release method is implemented using the full-bore suspension as described in claim 8, and the release method includes the following steps: During on-site operation, the insertion tube moves upward. When the reduced diameter section of the insertion tube moves upward to the position of the sealing claw, the sealing claw contracts due to its own elasticity and disengages from the annular groove of the cone body. If the sealing spring fails to retract properly during the upward movement of the insertion tube, the insertion tube continues to move upward, and the safety connector forcibly retracts the spring. The annular groove and the sealing spring are forcibly engaged, which helps the sealing spring retract and allows the user to release the device.

10. The method of dropping hands according to claim 9, characterized in that, If foreign objects become lodged in the insertion tube during the upward movement, rotate the insertion tube and the sealing claws will scrape off the lodged objects.

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