Float collar float shoe for well cementation and use method

Abstract

The invention relates to the field of float collars and float shoes, in particular to a float collar and float shoe for well cementation and a using method thereof, in actual well cementation operation, cement paste often contains solid-phase particles and additives and is prone to accumulating on the upper surface of a valve ball to form cement attachments, and the cement attachments are prone to falling off along with repeated use or time lapse. The hardened residues may cause that the valve ball and the sealing ring cannot be completely attached to each other to generate a small gap, so that the risks of sealing failure and cement paste leakage are caused, and the well cementation quality and the shaft integrity are seriously influenced. After cement paste impacts the valve element, attachments may remain on the surface of the valve element, a gap is formed between the surface of the valve element and the sealing part, shearing force is generated between the surface of the valve element and the static sealing part through rotation of the valve element, the attachments can be effectively scraped away or sheared, and rotation also ensures that the whole contact face of the valve element can scrape the sealing part. And cement paste leakage caused by local gaps is avoided.

Description

Technical Field

[0001] This invention relates to the field of float rings and float shoes, specifically to a cementing float ring and float shoe and its usage method. Background Technology

[0002] Cementing refers to the process of sealing the wellbore and reinforcing the formation by injecting cement slurry around the casing after drilling. This process protects the wellbore, stabilizes the formation, and prevents oil and gas from seeping from the formation to the wellhead, while ensuring safe production. It is a crucial step in oil and gas exploration and development. During cementing, various tools and equipment are typically used, such as cement pumps, casing, floats, and float shoes, to ensure that the cement slurry effectively fills the wellbore space and forms a solid cement sheath. The quality of cementing directly affects the safety, stability, and production efficiency of the oil well, making it an indispensable part of oil and gas exploration and development. Floats and float shoes are commonly used tools in cementing operations to ensure that the valve ball is in the correct position and protects it from the impact of the cement slurry when it is injected into the wellbore.

[0003] As a key component in cementing operations, floats and float shoes are primarily used to guide the flow of cement slurry and prevent backflow during cementing, and to achieve a sealing function through a built-in valve ball structure. In existing technologies, common floats and float shoes mostly adopt a ball valve structure, whose sealing mechanism relies on the contact seal between the valve ball and the seat ring. However, in actual cementing operations, cement slurry often contains solid particles and additives, which easily accumulate on the surface of the valve ball to form cement deposits. With repeated use or over time, these hardened residues may cause the valve ball and the sealing ring to not fit completely, creating micro-gaps, thereby leading to seal failure and the risk of cement slurry leakage, seriously affecting cementing quality and wellbore integrity. Summary of the Invention

[0004] The purpose of this invention is to provide a cementing float and its usage method to solve the problems mentioned in the background art. To achieve the above objective, this invention provides the following technical solution: A cementing float includes a shell, the top of which has a grouting port along its axial direction, the top inner part of which has a sealing part at the grouting port, the bottom inner part of which is connected to a sealing plate, and the sealing plate has a drainage hole for cement slurry to flow through, the top of which has an upper valve core vertically facing the grouting port, the upper valve core can remove cement slurry adhering to its surface when it contacts the sealing part, thereby improving the sealing performance, the sealing plate also has a lower valve core for sealing the drainage hole, the upper valve core and the lower valve core operate synchronously to achieve the sealing of the shell, improving the sealing reliability of the entire device.

[0005] Preferably, the upper valve core includes a fixed cylinder perpendicular to the sealing plate. A support rod is slidably connected to the fixed cylinder toward the grouting port. The fixed cylinder has a hollow structure and a return spring is installed inside. The return spring is connected to the end of the support rod that extends into the fixed cylinder. A support frame is fixedly connected to the outer wall of the support rod. The support frame is conical and has three universal connecting rods at its top. Each universal connecting rod is arranged obliquely along the circumference of the support frame and has the same slope as the support frame. An upper valve plate is connected to the end of each universal connecting rod away from the support frame. The universal connecting rods provide support for the upper valve plate in a triangular distribution. A compression spring is provided between the bottom of the upper valve plate and the top of the support rod. A valve core is provided at the top of the upper valve plate. The valve core is used to mate with the sealing part at the grouting port to achieve a seal and prevent cement slurry from entering the shell.

[0006] Preferably, both ends of the universal connecting rod are provided with spheres, which are respectively embedded in the support frame and the upper valve plate. The top of the upper valve plate is fixedly connected with an annular outer disc. The inner wall of the outer disc is provided with several protrusions along its circumference. When the protrusions come into contact with the sealing part, they can remove the adhering substances on the outer wall of the valve core.

[0007] Preferably, the sealing part includes a mounting bracket disposed at the top grouting port inside the housing, a sealing lip is mounted on the mounting bracket, and a plurality of elastic balls are disposed below the lip and along its circumference.

[0008] Preferably, the sealing part includes a mounting bracket, on which a sealing ring is mounted. The inner top of the mounting bracket is slidably connected to a section plate located outside the sealing ring. The section plate has an arc-shaped end that matches the arc surface of the valve core. The arc-shaped end is made of elastic silicone rubber or polyurethane material.

[0009] Preferably, a wedge block is provided perpendicular to the cut plate on the inner wall of the mounting bracket. The wedge block is telescopically connected to the mounting bracket through a connecting spring. The wedge-shaped surface of the wedge block engages with the wedge shape of the cut plate, which can push the cut plate to move radially toward the valve core. The protrusions provided on the inner wall of the outer disc intermittently contact the wedge block, driving the wedge block to telescopically move.

[0010] Preferably, each drainage hole is provided with a corresponding lower valve core, the lower valve core including a first connecting rod hinged to the outer wall of the support rod, a sealing plate is slidably connected to the sealing plate, the sealing plate is hinged to the end of the first connecting rod away from the support rod, and a second connecting rod is also hinged to the fixed cylinder, the second connecting rod being hinged to the first connecting rod to form a cross-link support mechanism.

[0011] Preferably, the method of using a cementing float band / float includes the following steps: S1: After grouting is completed, the return spring pushes the support rod to move upward, and through the support frame and universal connecting rod, it drives the upper valve plate and valve core to move toward the sealing part, so as to achieve the initial sealing of the grouting port; S2: The support rod continues to move upward to compress the compression spring. The inclined arrangement of the universal connecting rod causes the upper valve plate to rotate, which drives the valve core to rotate and contact the sealing lip, removing the surface deposits. S3: When the upper valve plate rotates, the protrusion on the outer sleeve plate contacts the elastic ball on the outer wall of the sealing lip, causing the sealing lip to vibrate, forming a dynamic seal and preventing contaminants from accumulating.

[0012] Compared with the prior art, the beneficial effects of the present invention are as follows: In this invention, after the cement slurry impacts the valve core, there may be residual deposits on its surface, resulting in a gap between it and the sealing part. The rotation of the valve core generates a shearing force between its surface and the stationary sealing part, which can effectively scrape off or shear the deposits. The rotation also ensures that the entire contact surface of the valve core can scrape against the sealing part, avoiding cement slurry leakage due to local gaps.

[0013] In this invention, when the valve core rotates, the vibration caused by the elastic ball breaks the cement slurry adhesion formed by static friction, avoiding the twisting or wear of the sealing lip due to excessive opening and closing torque. The vibration can also prevent contaminant particles from staying in the same position and grinding the sealing lip, making the wear more uniform and avoiding the formation of local deep grooves, thereby extending the service life of the sealing lip.

[0014] In this invention, when the valve core contacts the sealing lip to seal the grouting port, the edge of the sealing lip is in close contact with the outer wall of the valve core to form a line seal, and the elastic ball makes point contact with the outer wall of the valve core to form a secondary seal, thereby enhancing the sealing reliability. If tiny particles in the cement grout cause a small leak below the sealing lip, the auxiliary sealing point of the elastic ball can also block it, further improving the sealing performance of the grouting port.

[0015] In this invention, when the valve core and the sealing ring achieve a seal, the outer disc stops rotating, the wedge block remains stationary under the action of the connecting spring, and the arc end of the sectional plate abuts against the sealing ring, forming a rigid limit on the valve core. Through the rigid bearing and self-locking effect of the sectional plate, the impact resistance of the sealing structure is significantly enhanced, and leakage is completely prevented. Attached Figure Description

[0016] Figure 1 A cross-sectional view of the casing of the present invention. Figure 1 ; Figure 2 A cross-sectional view of the casing of the present invention. Figure 2 ; Figure 3 This is a plan view of the upper valve core, sealing part, and lower valve core in this invention; Figure 4 This is an exploded view of the upper valve core and sealing part in this invention; Figure 5 This is a three-dimensional structural diagram of the upper valve plate in the state where the universal connecting rod in the upper valve core drives the upper valve plate to rotate according to the present invention. Figure 6 This is a three-dimensional structural diagram of the sealing part and the outer ring of the present invention; Figure 7 This is a plan view of the sealing part and the outer ring of the present invention; Figure 8 This is a plan view of the sealing part and the outer ring according to the second embodiment of the present invention; Figure 9 This is a three-dimensional structural diagram of the lower valve core of the present invention.

[0017] In the diagram: 1. Shell; 11. Grouting port; 12. Drainage hole; 13. Sealing plate; 2. Upper valve core; 21. Fixed cylinder; 22. Support rod; 23. Return spring; 24. Support frame; 25. Universal connecting rod; 26. Upper valve plate; 27. Compression spring; 28. Valve core; 29. ​​Ball; 210. Outer disc; 211. Protrusion; 3. Sealing part; 31. Mounting bracket; 32. Sealing lip; 321. Elastic ball; 33. Sealing ring; 331. Section plate; 332. Arc end; 333. Wedge block; 4. Lower valve core; 41. First connecting rod; 42. Sealing disc; 43. Second connecting rod. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] Example 1:

[0020] Please see Figures 1 to 9 This invention provides a technical solution: a cementing float shoe, comprising a housing 1, wherein a grouting port 11 is provided on the top of the housing 1 along its axial direction, a sealing part 3 is provided on the inner top of the housing 1 at the grouting port 11, a sealing plate 13 is connected to the inner bottom of the housing 1, and a drainage hole 12 for cement slurry to flow is provided on the sealing plate 13, an upper valve core 2 is provided on the top of the sealing plate 13 vertically facing the grouting port 11, the upper valve core 2 can remove the cement slurry adhering to its surface when it contacts the sealing part 3, thereby improving the sealing performance, and a lower valve core 4 is also provided on the sealing plate 13 for sealing the drainage hole 12, the upper valve core 2 and the lower valve core 4 operate synchronously to achieve the sealing of the housing 1, thereby improving the sealing reliability of the entire device.

[0021] In this embodiment, the upper valve core 2 includes a fixed cylinder 21 perpendicular to the sealing plate 13. A support rod 22 is slidably connected to the fixed cylinder 21 toward the grouting port 11. The fixed cylinder 21 has a hollow structure and a return spring 23 is provided inside it. The return spring 23 is connected to the end of the support rod 22 that extends into the fixed cylinder 21. A support frame 24 is fixedly connected to the outer wall of the support rod 22. The support frame 24 is tapered and has three universal connecting rods 25 at its top. 5 is arranged obliquely along the circumferential direction of the support frame 24 and has the same slope as the support frame 24. The end of the universal connecting rod 25 away from the support frame 24 is connected to the upper valve plate 26. The universal connecting rod 25 provides support for the upper valve plate 26 in a triangular distribution. A compression spring 27 is provided between the bottom of the upper valve plate 26 and the top of the support rod 22. A valve core 28 is provided at the top of the upper valve plate 26. The valve core 28 is used to dock with the sealing part 3 at the grouting port 11 to achieve a seal and prevent cement slurry from entering the shell 1. Both ends of the universal connecting rod 25 are provided with balls 29, which are respectively embedded in the support frame 24 and the upper valve plate 26. The top of the upper valve plate 26 is fixedly connected with an annular outer disc 210. The inner wall of the outer disc 210 is provided with a number of protrusions 211 along its circumference. When the protrusions 211 come into contact with the sealing part 3, they can remove the adhering substances on the outer wall of the valve core 28. In the un-grouted state, the return spring 23 pushes the support rod 22 to move axially toward the grouting port 11, and the support frame 24 moves upward synchronously with the support rod 22, driving the upper valve plate 26 and the valve core 28 on its top to move toward the sealing part 3, and finally the grouting port 11 is sealed through the tight contact between the valve core 28 and the sealing part 3. Under the action of the return spring 23, the support rod 22 pushes the support frame 24 to move upward. The support frame 24 drives the upper valve plate 26 to move upward through the compression spring 27 and three sets of universal connecting rods 25. The outer sleeve plate 210 provided on the upper valve plate 26 abuts against the inner top of the housing 1 and surrounds the outer side of the sealing part 3. During this process, due to the limiting effect of the outer sleeve plate 210, the support rod 22 continues to move upward and compresses the compression spring 27. At the same time, because the universal connecting rods 25 are arranged at an angle, when the upper valve plate 26 and the support frame 24 are relatively displaced, the upper valve plate 26 will generate a circular motion, which will drive the valve core 28 to rotate, so that it makes rotational contact with the sealing part 3, thereby removing the contaminants attached to the outer wall of the valve core 28. After the cement slurry impacts the valve core 28, residues may remain on its surface, causing gaps between it and the sealing part 3. The rotation of the valve core 28 generates shearing force between its surface and the stationary sealing part 3, which can effectively scrape off or shear the residues. The rotation also ensures that the entire contact surface of the valve core 28 can scrape against the sealing part 3, avoiding cement slurry leakage due to local gaps.

[0022] In this embodiment, the sealing part 3 includes a mounting bracket 31 disposed at the top grouting port 11 inside the housing 1. A sealing lip 32 is mounted on the mounting bracket 31. Several elastic balls 321 are disposed below the lip of the sealing lip 32 along its circumference. The elastic balls 321 are integrally formed with the sealing lip 32 and can be made of elastic silicone rubber or polyurethane material. When the valve core 28 extends into the sealing lip 32, its rotational motion contacts the inner side of the sealing lip 32, removing surface deposits. At the same time, the upper valve plate 26 rotates, causing the protrusion 211 on the outer sleeve plate 210 to contact the elastic ball 321 on the outer wall of the sealing lip 32, causing the sealing lip 32 to vibrate. When the valve core 28 rotates, the vibration caused by the elastic ball 321 breaks the cement slurry adhesion formed by static friction, avoiding the twisting or wear of the sealing lip 32 due to excessive opening and closing torque. The vibration can also prevent contaminant particles from always staying in the same position to grind the sealing lip 32, making the wear more uniform and avoiding the formation of local deep grooves, thereby extending the service life of the sealing lip 32. When the valve core 28 contacts the sealing lip 32 to seal the grouting port 11, the edge of the sealing lip 32 is tightly attached to the outer wall of the valve core 28 to form a line seal. The elastic ball 321 makes point contact with the outer wall of the valve core 28 to form a secondary seal, which enhances the sealing reliability. If tiny particles in the cement grout cause a small leak below the sealing lip 32, the auxiliary sealing point of the elastic ball 321 can also block it, further improving the sealing performance of the grouting port 11.

[0023] In this embodiment, each drainage hole 12 is provided with a corresponding lower valve core 4. The lower valve core 4 includes a first connecting rod 41 hinged to the outer wall of the support rod 22. A sealing plate 42 is slidably connected to the sealing plate 13. The sealing plate 42 is hinged to the end of the first connecting rod 41 away from the support rod 22. A second connecting rod 43 is also hinged to the fixed cylinder 21. The second connecting rod 43 is hinged to the first connecting rod 41 to form a cross-link support mechanism. During grouting, the cement slurry at the grouting port 11 impacts the valve core 28, pushing the support rod 22 downwards, allowing the cement slurry to be injected into the housing 1. When the support rod 22 moves downwards, it drives the first connecting rod 41 to move, which in turn pushes the sealing disc 42 to move, opening the closed drainage hole 12. The cement slurry flows down into the well through the drainage hole 12. After grouting is completed, the pressure of the cement slurry on the upper valve core 2 disappears, and the return spring 23 pushes the support rod 22 to return to its original position. The upper valve core 2 then re-contacts the sealing part 3 to achieve a seal. At the same time, the sealing disc 42 seals the drainage hole 12. The bidirectional sealing mechanism further prevents cement slurry leakage.

[0024] Example 2:

[0025] To further improve the sealing performance of the valve core 28 and the sealing part 3 in a static state, such as Figure 8 The following improvements are made to Example 1: In this embodiment, the sealing part 3 includes a mounting bracket 31, on which a sealing ring 33 is mounted. The inner top of the mounting bracket 31 is slidably connected to a section plate 331 outside the sealing ring 33. The section plate 331 is provided with an arc end 332 that is adapted to the arc surface of the valve core 28. The arc end 332 is made of elastic silicone rubber or polyurethane material. A wedge block 333 is provided perpendicular to the section plate 331 on the inner wall of the mounting bracket 31. The wedge block 333 is telescopically connected to the mounting bracket 31 through a connecting spring. The wedge-shaped surface of the wedge block 333 is wedge-shapedly engaged with the section plate 331, which can push the section plate 331 to move radially toward the valve core 28. The protrusion 211 provided on the inner wall of the outer sleeve 210 is in intermittent contact with the wedge block 333, driving the wedge block 333 to telescopically move. When the outer disc 210 rotates, the protrusion 211 intermittently squeezes the wedge block 333, the wedge block 333 moves in extension and retraction and pushes the section plate 331 to move radially, the arc end 332 of the section plate 331 abuts against the outer wall of the sealing ring 33, and removes the adhering substances on the surface of the valve core 28. When the valve core 28 and the sealing ring 33 achieve a seal, the outer disc 210 stops rotating, the wedge block 333 remains stationary under the action of the connecting spring, and the arc end 332 of the section plate 331 abuts against the sealing ring 33, forming a rigid limit on the valve core 28. Through the rigid bearing and self-locking effect of the section plate 331, the impact resistance of the sealing structure is significantly enhanced, and leakage is completely prevented.

[0026] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A cementing float band / float shoe, comprising: The shell (1) has a grouting port (11) at its top and a sealing plate (13) connected to its bottom, with a drainage hole (12) on the sealing plate (13). Its features are: A sealing part (3) is provided at the top of the housing (1) and located at the grouting port (11); The upper valve core (2) is vertically set on the top of the sealing plate (13) and facing the grouting port (11) for contact and sealing with the sealing part (3); The upper valve core (2) includes: The fixed cylinder (21) is set perpendicular to the sealing plate (13); The support rod (22) is slidably connected inside the fixed cylinder (21) and is connected to the fixed cylinder (21) through the return spring (23); Support frame (24) is connected to the outer wall of support rod (22); Multiple universal connecting rods (25) are arranged obliquely along the circumference of the support frame (24), and their two ends are rotatably connected to the support frame (24) and the upper valve plate (26) respectively through balls (29); The upper valve plate (26) is connected to the top of the support rod (22) via a compression spring (27); The valve core (28) is located on the top of the upper valve plate (26) and is used to connect and seal with the sealing part (3); The outer plate (210) is fixedly connected to the top of the upper valve plate (26), and its inner wall is provided with a protrusion (211). The sealing part (3) includes: Mounting bracket (31) is located at the top inside the housing (1); A sealing lip (32) is mounted on a mounting bracket (31); Multiple elastic balls (321) are arranged around the circumference below the lip of the sealing lip (32).

2. The well cementing float band / float shoe according to claim 1, characterized in that: The valve core (28) is configured to generate a rotational motion when the support rod (22) moves axially, and to contact the inner surface of the sealing lip (32) to remove deposits; The protrusion (211) on the outer disc (210) comes into contact with the elastic ball (321), causing the sealing lip (32) to vibrate.

3. A cementing float band / float shoe according to claim 1, characterized in that: The sealing plate (13) is provided with a lower valve core (4) for sealing the drainage hole (12). The lower valve core (4) includes: The first connecting rod (41) is hinged to the outer wall of the support rod (22); The sealing disc (42) is slidably connected to the sealing plate (13) and hinged to the first connecting rod (41); The second link (43) is hinged to the fixed cylinder (21) and is hinged to the first link (41) to form a cross link mechanism.

4. A cementing float band / float shoe according to claim 1, characterized in that: The sealing part (3) further includes: A sealing ring (33) is installed on a mounting bracket (31); The cut-off plate (331) is connected to the mounting bracket (31) and located outside the sealing ring (33); The end of the cut plate (331) is provided with an arc end (332) that is compatible with the arc surface of the valve core (28). A wedge block (333) is set perpendicular to the section plate (331) and is telescopically connected to the mounting bracket (31) via a connecting spring. Its wedge-shaped surface is wedge-shaped and fits the section plate (331). The protrusions (211) on the inner wall of the outer disc (210) intermittently contact the wedge block (333), driving the wedge block (333) to extend and retract to push the section plate (331) to move radially.

5. A cementing float band / float shoe according to claim 1, characterized in that: The upper valve core (2) and the lower valve core (4) move synchronously through the axial movement of the support rod (22).

6. A cementing float band / float shoe according to claim 2, characterized in that: There are three universal connecting rods (25), which provide support for the upper valve plate (26) in a triangular distribution.

7. A method of using a cementing float band / float shoe, comprising using a cementing float band / float shoe as described in any one of claims 1-6, characterized in that, Includes the following steps: S1: After grouting is completed, the reset spring (23) pushes the support rod (22) to move upward, and through the support frame (24) and universal connecting rod (25), the upper valve plate (26) and valve core (28) move toward the sealing part (3) to achieve the initial sealing of the grouting port (11); S2: The support rod (22) continues to move upward to compress the compression spring (27), and the inclined arrangement of the universal connecting rod (25) causes the upper valve plate (26) to rotate, which drives the valve core (28) to rotate and contact the sealing lip (32) to remove the surface deposits; S3: When the upper valve plate (26) rotates, it contacts the elastic ball (321) on the outer wall of the sealing lip (32) through the protrusion (211) on the outer plate (210), causing the sealing lip (32) to vibrate, forming a dynamic seal and preventing contaminants from accumulating.

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