A multi-stage self-locking ball-catching circulation sub for half-cycle cementing and its control method

Abstract

This invention discloses a multi-stage self-locking ball-catching circulation sub and control method for half-stroke cementing, relating to the field of oil well cementing operation technology. It includes a sub assembly and an outer shell. The top of the outer shell has a discharge port. A displacement assembly is disposed within the outer shell, including a sliding sleeve slidably connected to the outer shell. The outer ring of the sliding sleeve has a receiving groove, within which a first ball is slidably connected. An upper connector is fixed to one end of the outer shell, and a lower connector is fixed to the other end. The beneficial effects of this invention are that, through the sub assembly and limiting assembly, after the second ball is inserted, the continuously supplied medium and pump pressure drive the displacement assembly to slide and complete the check valve locking operation, preventing the second ball from detaching arbitrarily and maintaining bypass requirements. Compared to traditional spring and rubber check valve structures, it offers better stability and ensures smooth cementing operations.

Description

Technical Field

[0001] This invention relates to the field of oil well cementing operation technology, and in particular to a multi-stage self-locking ball-catching circulation sub and control method for half-stroke cementing. Background Technology

[0002] In oil well cementing operations, cementing is an important operation in the drilling process. Cementing refers to the construction process of injecting cement slurry into the annular space between the wellbore and the casing after the casing is run into the well. Cementing is a key tool used to control the fluid circulation path in oil and gas drilling cementing operations. Its core function is to achieve wellbore cleaning, tool protection, and fluid management under complex working conditions through bypass design.

[0003] In existing technologies, the circulating short section generally completes the bypass operation by throwing a ball in conjunction with an elastic support, but it often lacks a stable reverse check function. When the annular pressure rises abnormally, the ball is prone to slipping and detaching, causing bypass failure and requiring the ball to be thrown again, resulting in low overall processing efficiency. Summary of the Invention

[0004] In view of the problems existing in the existing multi-stage self-locking ball-catching circulation subs for half-cycle cementing, the present invention is proposed.

[0005] Therefore, the problem that this invention aims to solve is that the circulating short sections in the prior art often do not have a stable reverse check function. When the annular pressure rises abnormally, the ball is prone to slipping and falling off, causing bypass failure and requiring the ball to be thrown again, resulting in low overall processing efficiency.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a multi-stage self-locking ball-catching circulation sub for half-cycle cementing, comprising,

[0007] A short section assembly includes an outer shell with a discharge port at its top. A displacement assembly is disposed within the outer shell, including a sliding sleeve slidably connected to the outer shell. A receiving groove is formed on the outer ring of the sliding sleeve, and a first ball is slidably connected within the receiving groove. An upper connector is fixed to one end of the outer shell, and a lower connector is fixed to the other end of the outer shell. A second ball is slidably connected within the sliding sleeve.

[0008] A limiting component is disposed on the outer ring of the outer shell, including a shear pin located inside the outer shell. A spring is fixed to one end of the shear pin, and a screw head is fixed to the other end of the spring. A movable block is rotatably connected to the top of the sliding sleeve, and a torsion spring is sleeved on the movable block.

[0009] As a preferred embodiment of the multi-stage self-locking ball-catching circulation sub for half-cycle cementing described in this invention, wherein: a first slot is provided in the outer shell, a second slot is provided in the outer shell, and the second slot is connected to the discharge port.

[0010] As a preferred embodiment of the multi-stage self-locking ball-catching circulation sub for half-cycle cementing described in this invention, wherein: the first slot and the second slot have the same inner diameter and both cooperate with the first ball; the number of receiving slots is three, and they are distributed in a circumferential array on the sliding sleeve.

[0011] As a preferred embodiment of the multi-stage self-locking ball-catching circulation sub for half-cycle cementing described in this invention, wherein: a positioning hole is provided at the top of the sliding sleeve, and a guide groove is provided at the bottom of the sliding sleeve, and both the positioning hole and the guide groove are slidably engaged with the shear pin.

[0012] As a preferred embodiment of the multi-stage self-locking ball-catching circulation sub for half-cycle cementing described in this invention, wherein: the top and bottom of the outer shell are provided with mounting holes and cooperate with shear pins, and the outer ring of the screw head is threaded into the mounting hole.

[0013] As a preferred embodiment of the multi-stage self-locking ball-catching circulation sub for half-cycle cementing described in this invention, wherein: one end of the shear pin contacts the movable block, and the outer ring of the sliding sleeve is provided with an auxiliary groove and slides in cooperation with the movable block.

[0014] As a preferred embodiment of the multi-stage self-locking ball-catching circulation sub for half-cycle cementing described in this invention, one end of the torsion spring is fixed to the movable block, and the other end of the torsion spring is fixed in the auxiliary groove.

[0015] As a preferred embodiment of the multi-stage self-locking ball-catching circulation sub for half-cycle cementing described in this invention, wherein: the inner ring of the outer shell is provided with an inclined groove, and one end of the movable block is slidably connected to the inclined groove.

[0016] As a preferred embodiment of the multi-stage self-locking ball-catching circulation sub for half-cycle cementing described in this invention, wherein: the outer ring of the sliding sleeve slides in contact with the inner ring of the outer casing and is sealed.

[0017] A control method for a multi-stage self-locking ball-catching circulation sub used in half-stroke cementing includes the following steps:

[0018] Step 1: According to the requirements of oil well cementing operations, multiple short section components are assembled and connected by upper and lower connectors to ensure installation stability and sealing. In the initial state, the sliding sleeve is in the closed state, the second ball is not placed in the sliding sleeve, the sliding sleeve blocks and covers the outlet, and the medium flows from the upper connector through the displacement component and the outer shell and is transmitted through the lower connector.

[0019] Step 2: When it is necessary to switch the discharge path, use the special operation tool to insert the tube column into the appropriate position, and then put the second ball into the upper connector.

[0020] Step 3: Continuously input the medium. When the medium conveying pressure is greater than the shearing value of the shearing pin, the shearing pin is cut off, the sliding sleeve slides to the open state, and at the same time the second ball is placed into the sliding sleeve, exposing the outlet, which allows the medium to flow out through a different channel.

[0021] The beneficial effects of this invention are as follows: by setting up the short section assembly and the limiting assembly, after the second ball is deployed, the displacement assembly can be driven to slide and displace in conjunction with the continuously supplied medium and pump pressure, and the check lock operation can be completed to prevent the second ball from falling off at will, thus maintaining the bypass requirement well. Compared with the traditional spring and rubber check structure, it has better stability and ensures that the cementing operation is carried out well. Attached Figure Description

[0022] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a structural diagram of a multi-stage self-locking ball-catching circulation sub used in half-cycle cementing.

[0024] Figure 2 This is a cross-sectional view of the closed state of a multi-stage self-locking ball-catching circulation sub used for half-cycle cementing.

[0025] Figure 3 This is a cross-sectional view of a multi-stage self-locking ball-catching circulation sub used for half-cycle cementing.

[0026] Figure 4 This is a side cross-section of the first sphere in a multi-stage self-locking ball-catching circulation sub used for half-way cementing.

[0027] Figure 5 This is a cross-sectional view of the open state of a multi-stage self-locking ball-catching circulation sub used for half-cycle cementing.

[0028] Figure 6 This is a side cross-sectional view of the first and second spheres of a multi-stage self-locking ball-catching circulation sub used for half-way cementing.

[0029] Figure 7 This is a partial structural diagram of the outer shell and sliding sleeve of a multi-stage self-locking ball-catching circulation sub used for half-cycle cementing.

[0030] Figure 8 For use in half-cycle cementing multi-stage self-locking ball-catching circulation sub Figure 7 Enlarged view of point A in the middle.

[0031] Figure 9 For use in half-cycle cementing multi-stage self-locking ball-catching circulation sub Figure 2Enlarged view of section B in the middle.

[0032] In the diagram: 1. Short section assembly; 11. Outer shell; 11-1. Discharge port; 11-2. First slot; 11-3. Second slot; 11-4. Mounting hole; 11-5. Inclined groove; 12. Displacement assembly; 12-1. Sliding sleeve; 12-11. Storage groove; 12-12. Positioning hole; 12-13. Guide groove; 12-14. Auxiliary groove; 12-2. First sphere; 13. Upper connector; 14. Lower connector; 15. Second sphere; 2. Limiting assembly; 21. Shear pin; 21-1. Spring; 21-2. Screw head; 22. Movable block; 22-1. Torsion spring. Detailed Implementation

[0033] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0034] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0035] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0036] Example 1

[0037] Reference Figure 1 and Figure 2 This is the first embodiment of the present invention. This embodiment provides a multi-stage self-locking ball-catching circulation sub for half-cycle cementing. The multi-stage self-locking ball-catching circulation sub for half-cycle cementing includes a sub assembly 1 and a limiting assembly 2. By setting the sub assembly 1 and the limiting assembly 2, after the ball-dropping operation, in conjunction with the continuously introduced medium and pump pressure, side bypass can be performed and check valve locking operation can be completed, which can well maintain the bypass requirement. Compared with the traditional spring and rubber check valve structure, the stability is better and the cementing operation can be carried out smoothly.

[0038] Specifically, the short section assembly 1 includes an outer shell 11, with a discharge port 11-1 at the top of the outer shell 11. A displacement assembly 12 is provided inside the outer shell 11, including a sliding sleeve 12-1 slidably connected inside the outer shell 11. A storage groove 12-11 is provided on the outer ring of the sliding sleeve 12-1. A first ball 12-2 is slidably connected inside the storage groove 12-11. An upper connector 13 is fixed at one end of the outer shell 11, and a lower connector 14 is fixed at the other end of the outer shell 11. A second ball 15 is slidably connected inside the sliding sleeve 12-1.

[0039] The outlet 11-1 can be used in conjunction with external pipelines to form a bypass opening for discharging cement media to the side.

[0040] By setting the displacement component 12, the discharge port 11-1 can be blocked in the initial state, allowing special tools to pass through and the second ball 15 to be inserted into the sliding sleeve 12-1 at different positions; in the open state, the discharge port 11-1 is exposed, the cement slurry is naturally bypassed and discharged, and the second ball 15 is protected against backflow.

[0041] Specifically, the limiting component 2 is set on the outer ring of the outer shell 11, including a shear pin 21 located inside the outer shell 11. One end of the shear pin 21 is fixed with a spring 21-1, and the other end of the spring 21-1 is fixed with a screw head 21-2. The top of the sliding sleeve 12-1 is rotatably connected to a movable block 22, and a torsion spring 22-1 is sleeved on the movable block 22.

[0042] By setting the limiting component 2, when the sliding sleeve 12-1 is in the sliding open state, the shear pin 21 is sheared and broken, and the movable block 22 moves the broken piece of the shear pin 21 out, avoiding contact damage between the irregular fracture surface and the sliding sleeve 12-1 or the outer shell 11.

[0043] Example 2

[0044] Reference Figures 2-9 This is the second embodiment of the present invention, which is based on the previous embodiment.

[0045] Specifically, a first slot 11-2 is provided inside the outer shell 11, and a second slot 11-3 is provided inside the outer shell 11. The second slot 11-3 is connected to the discharge port 11-1.

[0046] The first slot 11-2 and the second slot 11-3 have the same inner diameter and both fit with the first sphere 12-2. There are three storage slots 12-11, which are arranged in a circular array on the sliding sleeve 12-1.

[0047] Both sides of the inner cavities of the first slot 11-2 and the second slot 11-3 are chamfered to form beveled surfaces. During the displacement of the sliding sleeve 12-1, the first ball 12-2 contacts the beveled surface, causing the first ball 12-2 to automatically move inward until it contacts the inner wall of the outer shell 11. At this time, the first ball 12-2 protrudes from the inner ring of the sliding sleeve 12-1, as shown in the attached diagram of the instruction manual. Figure 6 As shown.

[0048] The top of the sliding sleeve 12-1 is provided with a positioning hole 12-12, and the bottom of the sliding sleeve 12-1 is provided with a guide groove 12-13. Both the positioning hole 12-12 and the guide groove 12-13 are slidably engaged with the shear pin 21.

[0049] By cooperating with the shear pin 21 and the positioning hole 12-12, the sliding sleeve 12-1 can be prevented from sliding freely in the positioning state, which would cause the discharge port 11-1 to open.

[0050] The shear pin 21 and the guide groove 12-13 are designed to guide the movement of the sliding sleeve 12-1, ensuring the stability of its linear displacement and preventing it from rotating arbitrarily.

[0051] The outer casing 11 has mounting holes 11-4 at the top and bottom, which cooperate with the shear pin 21. The outer ring of the screw head 21-2 is threaded into the mounting hole 11-4.

[0052] One end of the mounting hole 11-4 has a threaded design to engage with the threaded screw head 21-2, ensuring the installation stability of the screw head 21-2. The mounting hole 11-4 also provides sufficient space to accommodate the shearing pin 21.

[0053] One end of the shear pin 21 contacts the movable block 22, and the outer ring of the sliding sleeve 12-1 is provided with an auxiliary groove 12-14, which slides in cooperation with the movable block 22.

[0054] The auxiliary groove 12-14 is connected to the positioning hole 12-12. One end of the movable block 22 extends into the positioning hole 12-12 and contacts the shear pin 21. The auxiliary groove 12-14 can meet the space requirements for the movable block 22 to be stored and rotated. When the displacement component 12 is in the initial state, the bottom end of the movable block 22 contacts the inner wall of the auxiliary groove 12-14 and cannot rotate counterclockwise.

[0055] One end of the torsion spring 22-1 is fixed to the movable block 22, and the other end of the torsion spring 22-1 is fixed in the auxiliary groove 12-14.

[0056] By setting the torsion spring 22-1, torque can be provided to the movable block 22, and the movable block 22 can be prevented from rotating when no external force is applied.

[0057] The inner ring of the outer shell 11 has a slanted groove 11-5, and one end of the movable block 22 is slidably connected in the slanted groove 11-5.

[0058] Because the inner wall of the discharge port 11-1 is inclined, as shown in the attached diagram of the instruction manual. Figure 8 As shown, when the sliding sleeve 12-1 moves open, the movable block 22 moves accordingly, and its top end contacts the inclined surface of the inclined groove 11-5. The force is divided, causing the movable block 22 to automatically rotate clockwise and enter the auxiliary groove 12-14.

[0059] The outer ring of the sliding sleeve 12-1 slides in contact with the inner ring of the outer casing 11 and is sealed.

[0060] The storage slot 12-11 consists of a cylindrical slot and an arc-shaped slot, with the cylindrical slot located on the outer ring of the sliding sleeve 12-1 and the arc-shaped slot located on the inner ring of the sliding sleeve 12-1. The two are in a connected state and both slide in engagement with the first sphere 12-2. The first sphere 12-2 can slide freely within the cylindrical slot but cannot detach itself through the arc-shaped slot.

[0061] A valve seat is provided inside the sliding sleeve 12-1 to mate with the second ball 15, as shown in the attached diagram of the instruction manual. Figure 5 As shown, it is used to ensure the sealing of the contact between the second ball 15 and the sliding sleeve 12-1 when the second ball 15 is installed, so as to prevent material from leaking through the sliding sleeve 12-1.

[0062] The shear pin 21 includes a base and a pin shaft. The base is fixedly connected to the spring 21-1, and the other end of the base is fixedly connected to the pin shaft. The pin shaft is slidably fitted with the positioning hole 12-12, and the base is slidably fitted with the mounting hole 11-4. The diameter of the pin shaft is smaller than the diameter of the base body. A shearing ring groove is provided at the connection between the pin shaft and the base body, as shown in the attached diagram of the instruction manual. Figure 9 As shown.

[0063] The shearing groove is 2mm deep and 4mm smaller in diameter than the base material to ensure concentrated shear force.

[0064] With this design, when the pin is disconnected from the base, it can still be moved into the corresponding mounting hole 11-4 in the base after the pin has moved a certain distance.

[0065] Both mounting hole 11-4 and positioning hole 12-12 have chamfered surfaces. With this design, when the bottom end of shear pin 21 contacts the chamfer, the force distribution will automatically squeeze shear pin 21 into mounting hole 11-4.

[0066] The end of the shear pin 21 away from the spring 21-1 is an arc block made of polytetrafluoroethylene. While ensuring sturdiness and durability, it also has the advantage of low friction. When the shear pin 21 slides in contact with the outer ring of the sliding sleeve 12-1, it will not scratch the outer ring of the sliding sleeve 12-1.

[0067] The outer ring of the 12-1 sliding sleeve is equipped with two O-rings made of fluororubber, which are suitable for high-pressure environments.

[0068] A control method for a multi-stage self-locking ball-catching circulation sub used in half-stroke cementing includes the following steps:

[0069] Step 1: According to the requirements of oil well cementing operations, multiple short section components 1 are assembled vertically and connected by upper connector 13 and lower connector 14, ensuring installation stability and sealing. The upper connector 13 is located at the top of the short section component 1, and the lower connector 14 is located at the bottom of the short section component 1.

[0070] In the initial state, the sliding sleeve 12-1 is in the closed state, as shown in the attached diagram of the instruction manual. Figure 2 As shown, the second sphere 15 is not placed inside the sliding sleeve 12-1. The sliding sleeve 12-1 blocks and covers the discharge port 11-1. The medium flows from the upper connector 13 through the displacement component 12 and the outer shell 11 and is transmitted through the lower connector 14.

[0071] Step 2: When it is necessary to switch the discharge path, use the special tool to insert the tube column into the short section assembly 1 at the appropriate position, and then put the second ball 15 into the upper connector 13. At this time, the first ball 12-2 is placed in the first slot 11-2 and is in the storage state in the storage slot 12-11. The second ball 15 can directly enter the sliding sleeve 12-1.

[0072] Step 3: Continuously input the medium. Due to the sealed fit between the second ball 15 and the sliding sleeve 12-1, and the sealing of the outlet 11-1 by the sliding sleeve 12-1, the pressure on the sliding sleeve 12-1 gradually increases as the medium is introduced. When the medium delivery pressure exceeds the shearing value of the shearing pin 21, the shearing pin 21 located in the positioning hole 12-12 is sheared by the force, and the medium pushes the second ball 15 and the sliding sleeve 12-1 to slide to the open state, as shown in the attached diagram of the instruction manual. Figure 5 As shown, the discharge port 11-1 is exposed, allowing the medium to bypass and flow out.

[0073] Step 4: When the corresponding shearing pin 21 is cut, its cut surface is uneven. When the sliding sleeve 12-1 moves a certain distance, the movable block 22 contacts the inclined groove 11-5 and is squeezed, retracting into the auxiliary groove 12-14 and rotating. When the movable block 22 rotates, its end inclined surface pushes the shearing pin 21, overcoming the elastic force of the spring 21-1 and retracting into the mounting hole 11-4, so that the shearing pin 21 is completely retracted into the mounting hole 11-4, and the spring 21-1 is compressed.

[0074] Step 5: As the sliding sleeve 12-1 continues to slide, one end of the shear pin 21 slides into contact with the sliding sleeve 12-1, avoiding friction damage to the sliding sleeve 12-1 or the outer shell 11 caused by the uneven shear surface.

[0075] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A multi-stage self-locking ball-catching circulation sub for half-stroke cementing, characterized in that: include, The short section assembly (1) includes an outer shell (11), the top of which has a discharge port (11-1), and a displacement assembly (12) is provided inside the outer shell (11), including a sliding sleeve (12-1) slidably connected inside the outer shell (11). The outer ring of the sliding sleeve (12-1) has a receiving groove (12-11), and a first ball (12-2) is slidably connected inside the receiving groove (12-11). One end of the outer shell (11) is fixed with an upper connector (13), and the other end of the outer shell (11) is fixed with a lower connector (14). A second ball (15) is slidably connected inside the sliding sleeve (12-1); and... The limiting component (2) is set on the outer ring of the outer shell (11) and includes a shear pin (21) located inside the outer shell (11). One end of the shear pin (21) is fixed with a spring (21-1), and the other end of the spring (21-1) is fixed with a screw head (21-2). The top of the sliding sleeve (12-1) is rotatably connected to a movable block (22), and a torsion spring (22-1) is sleeved on the movable block (22). The outer shell (11) is provided with a first slot (11-2) and a second slot (11-3), which is connected to the discharge port (11-1); The first slot (11-2) and the second slot (11-3) have the same inner diameter and both fit with the first sphere (12-2). There are three storage slots (12-11), which are arranged in a circular array on the sliding sleeve (12-1). The top of the sliding sleeve (12-1) is provided with a positioning hole (12-12), and the bottom of the sliding sleeve (12-1) is provided with a guide groove (12-13). The positioning hole (12-12) and the guide groove (12-13) are both slidably engaged with the shear pin (21). The outer shell (11) has mounting holes (11-4) at the top and bottom, which cooperate with shear pins (21). The outer ring of the screw head (21-2) is threaded into the mounting hole (11-4).

2. The multi-stage self-locking ball-catching circulation sub for half-stroke cementing as described in claim 1, characterized in that: One end of the shear pin (21) is in contact with the movable block (22), and the outer ring of the sliding sleeve (12-1) is provided with an auxiliary groove (12-14) and slides in cooperation with the movable block (22).

3. The multi-stage self-locking ball-catching circulation sub for half-stroke cementing as described in claim 1, characterized in that: One end of the torsion spring (22-1) is fixed to the movable block (22), and the other end of the torsion spring (22-1) is fixed in the auxiliary groove (12-14).

4. The multi-stage self-locking ball-catching circulation sub for half-stroke cementing as described in claim 1, characterized in that: The inner ring of the outer shell (11) is provided with a slanted groove (11-5), and one end of the movable block (22) is slidably connected in the slanted groove (11-5).

5. The multi-stage self-locking ball-catching circulation sub for half-stroke cementing as described in claim 1, characterized in that: The outer ring of the sliding sleeve (12-1) slides in contact with the inner ring of the outer shell (11) and is sealed.

6. A control method for a multi-stage self-locking ball-catching circulation sub used in half-stroke cementing, characterized in that: Including the multi-stage self-locking ball-catching circulation sub for half-stroke cementing as described in any one of claims 1-5, it further includes the following steps: Step 1: According to the requirements of the well cementing operation, multiple short section components (1) are assembled and connected by the upper connector (13) and the lower connector (14) to ensure installation stability and sealing. In the initial state, the sliding sleeve (12-1) is in the closed state, the second ball (15) is not placed in the sliding sleeve (12-1), the sliding sleeve (12-1) covers the outlet (11-1), and the medium flows from the upper connector (13) through the displacement component (12) and the outer shell (11) and is transmitted through the lower connector (14). Step 2: When it is necessary to switch the discharge path, use the special working tool to insert the tube column into the appropriate position, and then put the second ball (15) into the upper connector (13); Step 3: Continuously input the medium. When the medium conveying pressure is greater than the shearing value of the shearing pin (21), the shearing pin (21) is cut off, the sliding sleeve (12-1) slides to the open state, and at the same time the second ball (15) is placed into the sliding sleeve (12-1), the discharge port (11-1) is exposed, and the medium can be diverted to flow out.

Images