One-trip multi-stage ball seat mechanism and cementing method

Abstract

The application provides a one-trip multi-stage linkage ball seat mechanism and a cementing method, and the ball seat mechanism comprises: an outer shell connected in a pipe string and arranged below a setting / setting and sealing tool; and a split ball seat arranged in the inner part of the outer shell, wherein the split ball seat comprises a plurality of split ball seat bodies; wherein the split ball seat bodies are arranged in a circumferential direction, the lower ends of the split ball seat bodies are gathered towards the middle part of the split ball seat and form a tapered structure, and the split ball seat bodies can bear a pressure holding ball. The application solves the construction process problem that one-time ball throwing and multi-stage setting / setting and sealing actions cannot be realized on a cementing construction site, and ensures the safety and reliability of the cementing construction process.

Description

Technical Field

[0001] The present invention relates to a one-trip multi-stage linkage ball seat mechanism and a cementing method, belonging to the field of oil well cementing tools. Background Art

[0002] For vertical wells constructed with a one-time string, a sulfide metal ball of a matching size is dropped. Due to its own weight, the sulfide metal ball will smoothly fall into the ball seat opening and cooperate with the inner conical surface of the ball seat. After the bump pressure, the string pressure rises. When the pressure inside the pipe reaches the design value of the cementing engineer, the packer can be set or the liner hanger can be landed. Subsequently, continue to pump pressure to make the sulfide metal ball block the ball seat pin, and then it falls into the bottom recovery cage to complete the construction action of a cementing tool.

[0003] Currently, the setting ball seat supporting the packer or the liner hanger generally can only perform one ball drop and setting operation, that is, a sulfide metal ball can only complete one setting / landing action before blocking the ball seat. However, with the development of more and more deep wells and ultra-deep wells, the more complex downhole environment poses higher requirements on cementing tools. To save the construction cost and time of cementing engineering, it is often necessary to complete two landings or even multi-stage linkages with one ball drop.

[0004] With the existing cementing technology, the ball seat is usually set below the cementing tools that need to perform actions such as packers / liner hangers / restraining nipples in the string structure and above the cementing tool accessories that do not need to perform actions such as float collars and float shoes. By adjusting the shear pressure of the pins inside different cementing tools, their set actions are controlled to be completed in sequence. However, relying on the existing method will result in too much pressure to block the bottom ball seat, and there are certain construction safety hazards. Summary of the Invention

[0005] In view of the above technical problems existing in the prior art, the present invention proposes a one-trip multi-stage linkage ball seat mechanism to solve the construction process problem that multi-stage landing / setting actions cannot be achieved with one ball drop at the cementing construction site and ensure the safety and reliability of the cementing construction process.

[0006] In addition, the present invention also proposes a cementing method.

[0007] According to one aspect of the present invention, a one-trip multi-stage linkage ball seat mechanism is proposed, including:

[0008] A housing, which is connected in the string and is arranged below the landing or setting tool; and

[0009] A split ball seat arranged inside the housing, the split ball seat including a plurality of split ball seat bodies;

[0010] The segmented ball seat is arranged circumferentially, with its lower end converging towards the center of the segmented ball seat to form a conical structure, which can support the pressure ball.

[0011] A further improvement of the present invention is that the segmented ball seat can deform when the pressure inside the tubing reaches a first set value, causing the pressure-reducing ball to detach from the segmented ball seat.

[0012] A further improvement of the present invention is that when the pressure inside the tubing reaches a second set value, the sitting or sealing tool completes the sitting or sealing under the action of the pressure, and the second set value is less than the first set value.

[0013] A further improvement of the present invention is that the split ball seat includes a connecting section connected to the outer shell, and the outer wall of the connecting section is connected to the inner wall of the outer shell by a connector;

[0014] The lower end of the connecting section is provided with a support section, which is inclined towards the inside of the outer shell.

[0015] A further improvement of the present invention is that the connecting member is a fixing bolt, and the segmented ball seat is made of an easily drillable material.

[0016] A further improvement of the present invention is that the pressure ball is a vulcanized pressure ball.

[0017] A further improvement of the present invention is that the upper end of the outer shell is provided with a female sleeve buckle and the lower end is provided with a male sleeve buckle.

[0018] According to another aspect of the invention, a cementing method is also proposed, which uses the aforementioned one-pass multi-stage linkage ball seat mechanism for cementing operations.

[0019] A further improvement of the present invention is that it provides a tube string, the tube string comprising, from top to bottom, a balance cylinder type tailpipe hanger, a first-stage ball seat, a restraining short section, a second-stage ball seat, a float band, and a float shoe;

[0020] Among them, at least the first-level ball seat is the aforementioned one-pass multi-level linkage ball seat mechanism.

[0021] A further improvement of the present invention is that the method includes the following steps:

[0022] The design depth from the bottom of the tubing string to the bottom of the well is reached by dropping a pressure-absorbing ball above the wellhead. The pressure-absorbing ball is then pressed against the first-stage ball seat position by the drilling fluid.

[0023] When the pressure reaches the second set value, the balance cylinder type tailpipe hanger completes the sitting and hanging action;

[0024] Continue to pressurize until the first set value is reached, thus opening the segmented ball seat and causing the pressurized ball to fall to the second-level ball seat;

[0025] The pressure is increased to the settling pressure of the restraining short section, causing the restraining short section to complete settling, and pressure is continued until the second-stage ball seat is vented;

[0026] After the cement slurry has completely solidified, the drilling tool is lowered to remove the split ball seat, completing one cementing operation.

[0027] Compared with the prior art, the present invention has the following advantages.

[0028] The ball seat mechanism of the present invention solves the construction process problem that it is impossible to achieve multi-stage setting / sealing actions in a single ball drop at the cementing construction site, and ensures the safety and reliability of the cementing construction process.

[0029] The ball seat mechanism of the present invention has a simple structure and a scientific and reasonable design: the ball seat mechanism consists of only four parts, which are quick and convenient to assemble, meeting the needs of quick and simple use on site; by precisely controlling the thickness of the segmented ball seat, the effect of precisely controlling the ball seat pressure is achieved.

[0030] According to the multi-stage linkage ball seat mechanism of the present invention, by combining it with a conventional ball seat, a two-stage sitting / sealing action can be achieved; if two multi-stage linkage ball seats and one conventional ball seat are combined, a three-stage sitting / sealing action can be achieved. Similarly, if the wear on the surface of the vulcanized pressure ball is ignored, an unlimited number of action processes can be achieved by increasing the number of linkage ball seats in the tube string.

[0031] According to the ball seat mechanism of the present invention, since the inner core material is made of a soft metal that is easy to drill out, the ball seat mechanism can be quickly drilled out by a drill bit. Attached Figure Description

[0032] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, in which:

[0033] Figure 1 The diagram shown is a schematic diagram of a single-pass multi-stage linkage ball seat mechanism according to an embodiment of the present invention.

[0034] Figure 2 The diagram shown is a structural schematic of a split ball seat body according to an embodiment of the present invention;

[0035] It should be noted that the accompanying drawings are not necessarily drawn to scale.

[0036] The meanings of the reference numerals in the attached figures are as follows:

[0037] 10. Outer shell, 11. Casing female thread, 12. Casing male thread, 13. Fixing bolt, 20. Split ball seat, 21. Split ball seat body, 22. Connecting section, 23. Supporting section, 24. Bolt hole, 30. Backpressure ball. Detailed implementation mode

[0038] In order to make the technical solutions and advantages of the present invention clearer and more understandable, the exemplary embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than an exhaustive list of all embodiments. And without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other.

[0039] For a vertical well constructed with a one-time string, a sulfide metal ball of a matching size is put in. Due to its own weight, the sulfide metal ball will smoothly fall into the ball seat opening and cooperate with the inner conical surface of the ball seat. After bumping pressure, the string pressure rises. When the pressure in the pipe reaches the design value of the cementing engineer, the packer can be set or the liner hanger can be set and hung. Subsequently, continue to pressurize to make the sulfide metal ball break through the ball seat pin and thus fall into the bottom recovery cage, completing the construction action of a cementing tool.

[0040] Currently, the setting ball seat supporting the packer or the liner hanger generally can only perform one-time ball setting and setting, that is, a sulfide metal ball can only complete one setting / hanging action before breaking through the ball seat. However, with the development of more and more deep wells and ultra-deep wells, the more complex downhole environment puts higher requirements on cementing tools. To save the construction cost and construction time of cementing engineering, it is often necessary to complete two settings or even multi-stage linkage with one-time ball injection.

[0041] In the existing cementing technology, usually the ball seat is arranged below the cementing tools such as the packer / liner hanger / restraining sub that need to perform actions in the string structure and above the cementing tool accessories such as the float collar and float shoe that do not need to perform actions. By adjusting the shear pressure of the pins inside different cementing tools, their set actions are controlled to be completed in sequence. However, relying on the existing method will cause the pressure to break through the bottom ball seat to be too high, and there are certain construction safety hazards.

[0042] In the embodiment as Figure 1 shown, the one-trip multi-stage linkage ball seat mechanism according to the present invention includes:

[0043] An outer shell 10, the outer shell 10 is of a cylindrical structure, connected in the string and arranged below the setting or setting tool and above the next-level ball seat. The next-level ball seat can be a common ball seat or the ball seat mechanism described in this embodiment.

[0044] A split ball seat 20 arranged inside the outer shell 10, the split ball seat 20 includes a plurality of split ball seat bodies 21;

[0045] The segmented ball seat 21 is arranged circumferentially, with its lower end converging toward the center of the segmented ball seat 20 to form a conical structure.

[0046] In this embodiment, a small hole is formed at the end of the conical structure formed at the lower end of the segmented ball seat 21, allowing fluid to flow. When the pressure-holding ball 30 is inserted, the pressure-holding ball 30 falls into the conical structure and blocks the small hole, separating the upper and lower parts of the segmented ball seat 20. Under the action of the well pressure, the setting or sealing of the tool is completed. If the pressure is continued, the segmented ball seat 20 will open under the action of the pressure, and the pressure-holding ball 30 will pass through the segmented ball seat 20 and fall to the next stage ball seat, or complete a cementing process and fall to the bottom of the well.

[0047] In the ball seat mechanism of the single-pass multi-stage linkage according to this embodiment, the outer shell 10 can be a cylindrical short section structure, connected to the column and set between the seat or sealing tool and the ordinary ball seat. After the pressure ball 30 is put in, the pressure ball 30 will fall onto the split ball seat 20 to realize pressure above the split ball seat 20. Under the action of pressure, the seat or sealing tool is driven to complete the seat or sealing.

[0048] In one embodiment, the segmented ball seat 21 has a certain supporting capacity and a certain deformation capacity. When the pressure inside the tubing reaches a first set value, the segmented ball seat 21 can deform, causing the pressure-reducing ball 30 to detach from the segmented ball seat 20.

[0049] In a preferred embodiment, the setting or sealing tool completes setting or sealing under the action of a second set value when the pressure inside the tubing reaches a second set value, and the second set value is less than the first set value. Thus, after the pressure-holding ball 30 falls into the split ball seat 20, pressure is applied from the wellhead to increase the pressure inside the tubing. When the pressure reaches the second set value, the setting or sealing tool is driven to complete setting or sealing under the pressure. Then, the pressure inside the tubing is increased until it reaches the first set value, causing the split ball seat 20 to deform and the pressure-holding ball 30 to detach from the split ball seat 20.

[0050] In one embodiment, the split ball seat 21 includes a connecting section 22 connected to the outer shell 10, and the outer wall of the connecting section 22 is connected to the inner wall of the outer shell 10 by a connector.

[0051] The lower end of the connecting section 22 is provided with a support section 23, which is inclined toward the inside of the outer shell 10.

[0052] In the ball seat mechanism with multi-stage linkage according to this embodiment, the connecting end of the segmented ball seat body 21 is an arc-shaped structure that matches the arc surface of the inner wall of the outer shell 10. Multiple segmented ball seat bodies 21 are arranged side by side along the circumference to form a circle.

[0053] The connecting section 22 of the split ball seat 21 is fixedly connected to the outer shell 10 by a connector.

[0054] The support section 23 is inclined towards the inside of the outer shell 10. The support sections 23 of the multiple segmented ball seats 21 are arranged side by side to form a conical structure. The multiple segmented ball seats 21 are arranged side by side and closely attached. Two adjacent support sections can be connected or separated.

[0055] In one embodiment, the connector is a fixing bolt 13, which firmly fixes the split ball seat 20 to the outer shell 10 and prevents it from falling off with the pressure ball 30. Therefore, the steel grade of the fixing bolt 13 is required to ensure that the fixing bolt 13 can withstand a pressure of at least a second set value.

[0056] The split ball seat 20 is made of an easily drillable material, including but not limited to 2A12 aluminum alloy and H62 brass, which are easily drillable.

[0057] Preferably, the pressure-blocking ball 30 is a vulcanized pressure-blocking ball. The vulcanized pressure-blocking ball is a non-connecting component and is deployed at the wellhead when the ball seat needs to be activated. The inner core of the vulcanized pressure-blocking ball is a metal ball, and the outer skin is vulcanized rubber. The metal ball in the inner core provides gravity and overall strength, while the vulcanized rubber on its outer surface can form a seal with the inner surface of the segmented ball seat 20, thereby blocking the flow of the ball seat.

[0058] In one embodiment, the upper end of the outer casing 10 is provided with a female sleeve buckle 11, and the lower end of the outer casing 10 is provided with a male sleeve buckle 12.

[0059] In this embodiment, the outer shell 10 of the ball seat mechanism can be adaptively matched according to the buckle type and specification size of the sleeve string, so the ball seat mechanism can be adapted to all specifications and types of sleeves.

[0060] The ball seat mechanism of the single-pass multi-stage linkage described in this embodiment has a simple structure and a scientific and reasonable design: the ball seat mechanism consists of only four parts, which are quick and convenient to assemble and meet the needs of quick and simple use on site; by precisely controlling the thickness of the split ball seat 20, the effect of precisely controlling the ball seat pressure is achieved.

[0061] According to another aspect of the present invention, a cementing method is also proposed, wherein the method uses the single-pass multi-stage linkage ball seat mechanism described in the above embodiments for cementing operations.

[0062] The method includes proposing a pipe string, the pipe string including a mounting or sealing tool, such as a balance cylinder type tailpipe hanger, a restraining short section, etc. In this embodiment, the balance cylinder type tailpipe hanger is mounted on the pipe column, and a first-stage ball seat is provided below it. The first-stage ball seat is the single-pass multi-stage linkage ball seat mechanism described in this invention. A restraining short section is provided below the first-stage ball seat, and a second-stage ball seat is provided below the restraining short section. In this embodiment, the second-stage ball seat is a common ball seat; of course, the single-pass multi-stage linkage ball seat mechanism can also be selected according to actual needs. A float band and a float shoe are provided below the second-stage ball seat.

[0063] In this embodiment, more stages of mounting or sealing tools and ball seats can be added to the pipe string according to the actual situation.

[0064] According to the method described in this embodiment, a single-pass multi-stage linkage ball seat mechanism combined with a conventional ball seat can achieve two-stage sitting or sealing. If two of the multi-stage linkage ball seats and one conventional ball seat are used, three-stage sitting or sealing can be achieved. Similarly, if the wear on the surface of the vulcanized pressure ball is ignored, an unlimited number of action processes can be achieved by increasing the number of linkage ball seats in the tube string.

[0065] In one embodiment, the method includes the following steps:

[0066] The design depth from the bottom of the tubing string to the bottom of the well is reached, and a pressure-absorbing ball 30 is dropped above the wellhead. The pressure-absorbing ball 30 is pressed by the drilling fluid as it reaches the first-stage ball seat position.

[0067] When the pressure reaches the second set value, the balance cylinder type tailpipe hanger completes the sitting and hanging action;

[0068] Continue to pressurize until the first set value is reached, thus opening the segmented ball seat 20 and causing the pressurized ball 30 to fall to the second-stage ball seat;

[0069] The pressure is increased to the settling pressure of the restraining short section, causing the restraining short section to complete settling, and pressure is continued until the second-stage ball seat is vented;

[0070] After the cement slurry has completely solidified, the drill string is lowered to remove the split ball seat 20, completing one cementing operation.

[0071] The method described in this embodiment solves the construction process problem of not being able to achieve multi-stage setting / sealing actions in a single ball dropping operation at the cementing construction site, and ensures the safety and reliability of the cementing construction process.

[0072] According to the ball seat mechanism of the present invention, since the inner core material is made of a soft metal that is easy to drill out, the ball seat mechanism can be quickly drilled out by a drill bit.

[0073] The following description uses specific examples to illustrate the point.

[0074] Example 1

[0075] A single-pass, multi-stage linkage ball seat mechanism includes:

[0076] The outer casing 10 is connected to the column and positioned below the seat or sealing tool, and above the next-level ball seat.

[0077] A segmented ball seat 20 is disposed inside the outer casing 10, the segmented ball seat 20 comprising a plurality of segmented ball seat bodies 21;

[0078] The segmented ball seat 21 is arranged circumferentially, with its lower end converging toward the center of the segmented ball seat 20 to form a conical structure.

[0079] The lower end of the cone-shaped structure of the segmented ball seat 21 forms a small hole that allows fluid to flow. When the pressure-holding ball 30 is inserted, it falls into the cone-shaped structure and blocks the small hole, separating the upper and lower parts of the segmented ball seat 20. Under the pressure inside the well, the setting or sealing of the tool is completed. If the pressure is continued, the segmented ball seat 20 will open under the pressure, and the pressure-holding ball 30 will pass through the segmented ball seat 20 and fall to the next stage ball seat, or complete a cementing process and fall to the bottom of the well.

[0080] The segmented ball seat 21 has a certain supporting capacity and a certain deformation capacity. When the pressure inside the tubing reaches a first set value, the segmented ball seat 21 can deform, causing the pressure-reducing ball 30 to detach from the segmented ball seat 20.

[0081] When the pressure inside the tubing reaches a second set value, the setting or sealing tool completes the setting or sealing under the action of that pressure, and the second set value is less than the first set value. Thus, after the pressure-holding ball 30 falls into the segmented ball seat 20, pressure is applied from the wellhead to increase the pressure inside the tubing. When the pressure reaches the second set value, the setting or sealing tool is driven to complete the setting or sealing. Then, the pressure inside the tubing is increased until it reaches the first set value, causing the segmented ball seat 20 to deform and the pressure-holding ball 30 to detach from the segmented ball seat 20.

[0082] The split ball seat 21 includes a connecting section 22 connected to the outer shell 10. The outer wall of the connecting section 22 is connected to the inner wall of the outer shell 10 by fixing bolts 13. A support section 23 is provided at the lower end of the connecting section 22. The support section 23 is inclined towards the inside of the outer shell 10.

[0083] The connecting end of the segmented ball seat 21 has an arc-shaped structure, which matches the arc surface of the inner wall of the outer shell 10. Multiple segmented ball seats 21 are arranged side by side along the circumference to form a circle. The connecting section 22 of the segmented ball seat 21 is fixedly connected to the outer shell 10 by a connector.

[0084] The support section 23 is inclined towards the inside of the outer shell 10. The support sections 23 of the multiple segmented ball seats 21 are arranged side by side to form a conical structure. The multiple segmented ball seats 21 are arranged side by side and closely attached to each other.

[0085] The split ball seat 20 is made of an easy-to-drill material, specifically 2A12 aluminum alloy.

[0086] The pressure-blocking ball 30 is a vulcanized pressure-blocking ball. The vulcanized pressure-blocking ball is a non-connecting component and is deployed at the wellhead when the ball seat needs to be activated. The inner core of the vulcanized pressure-blocking ball is a metal ball, and the outer skin is vulcanized rubber. The inner metal ball provides gravity and overall strength, while the vulcanized rubber on its outer surface can form a seal with the inner surface of the segmented ball seat 20, thereby blocking the flow of the ball seat.

[0087] The upper end of the outer shell 10 is provided with a female sleeve buckle 11, and the lower end of the outer shell 10 is provided with a male sleeve buckle 12.

[0088] Example 2

[0089] A multi-stage ball seat mechanism includes: a housing 10 connected to a column and positioned below the seat or sealing tool, and above the next-stage ball seat. A segmented ball seat 20 is disposed inside the housing 10, the segmented ball seat 20 comprising a plurality of segmented ball seat bodies 21; wherein the segmented ball seat bodies 21 are arranged circumferentially, their lower ends converging towards the center of the segmented ball seat 20 to form a conical structure.

[0090] The lower end of the cone-shaped structure of the segmented ball seat 21 forms a small hole that allows fluid to flow. When the pressure-holding ball 30 is inserted, it falls into the cone-shaped structure and blocks the small hole, separating the upper and lower parts of the segmented ball seat 20. Under the pressure inside the well, the setting or sealing of the tool is completed. If the pressure is continued, the segmented ball seat 20 will open under the pressure, and the pressure-holding ball 30 will pass through the segmented ball seat 20 and fall to the next stage ball seat, or complete a cementing process and fall to the bottom of the well.

[0091] The segmented ball seat 21 has a certain supporting capacity and a certain deformation capacity. When the pressure inside the tubing reaches a first set value, the segmented ball seat 21 can deform, causing the pressure-reducing ball 30 to detach from the segmented ball seat 20.

[0092] When the pressure inside the tubing reaches a second set value, the setting or sealing tool completes the setting or sealing under the action of that pressure, and the second set value is less than the first set value. Thus, after the pressure-holding ball 30 falls into the segmented ball seat 20, pressure is applied from the wellhead to increase the pressure inside the tubing. When the pressure reaches the second set value, the setting or sealing tool is driven to complete the setting or sealing. Then, the pressure inside the tubing is increased until it reaches the first set value, causing the segmented ball seat 20 to deform and the pressure-holding ball 30 to detach from the segmented ball seat 20.

[0093] The split ball seat 21 includes a connecting section 22 connected to the outer shell 10. The outer wall of the connecting section 22 is connected to the inner wall of the outer shell 10 by fixing bolts 13. A support section 23 is provided at the lower end of the connecting section 22. The support section 23 is inclined towards the inside of the outer shell 10.

[0094] The connecting end of the segmented ball seat 21 has an arc-shaped structure, which matches the arc surface of the inner wall of the outer shell 10. Multiple segmented ball seats 21 are arranged side by side along the circumference to form a circle. The connecting section 22 of the segmented ball seat 21 is fixedly connected to the outer shell 10 by a connector.

[0095] The support section 23 is inclined towards the inside of the outer shell 10. The support sections 23 of the multiple segmented ball seats 21 are arranged side by side to form a conical structure. The multiple segmented ball seats 21 are arranged side by side and closely attached to each other.

[0096] In this embodiment, the split ball seat 20 is made of H62 brass, and the other structures are the same as in Embodiment 1.

[0097] Example 3

[0098] A pipe string includes a mounting or sealing tool, such as a balance cylinder type tailpipe hanger, a restraining short section, etc. In this embodiment, the balance cylinder type tailpipe hanger is mounted on the pipe string, and a first-stage ball seat is provided below it. The first-stage ball seat is a single-pass multi-stage linkage ball seat mechanism as described in Embodiment 1 or Embodiment 2. A restraining short section is provided below the first-stage ball seat, and a second-stage ball seat is provided below the restraining short section. In this embodiment, the second-stage ball seat is a common ball seat.

[0099] Example 4

[0100] A tube string, the tube string comprising three sets of mounting or sealing tools and a three-stage ball seat, wherein the first-stage ball seat and the second-stage ball seat are both the single-pass multi-stage linkage ball seat mechanism described in this invention, and the third-stage ball seat is a common ball seat.

[0101] Example 5

[0102] A cementing method, the method comprising the following steps:

[0103] The design depth from the bottom of the tubing string to the bottom of the well is reached, and a pressure-absorbing ball 30 is dropped above the wellhead. The pressure-absorbing ball 30 is pressed by the drilling fluid as it reaches the first-stage ball seat position.

[0104] When the pressure reaches the second set value, the balance cylinder type tailpipe hanger completes the sitting and hanging action;

[0105] Continue to pressurize until the first set value is reached, thus opening the segmented ball seat 20 and causing the pressurized ball 30 to fall to the second-stage ball seat;

[0106] The pressure is increased to the settling pressure of the restraining short section, causing the restraining short section to complete settling, and pressure is continued until the second-stage ball seat is vented;

[0107] After the cement slurry has completely solidified, the drill string is lowered to remove the split ball seat 20, completing one cementing operation.

[0108] The method described in this embodiment solves the construction process problem of not being able to achieve multi-stage setting / sealing actions in a single ball dropping operation at the cementing construction site, and ensures the safety and reliability of the cementing construction process.

[0109] According to the ball seat mechanism of the present invention, since the inner core material is made of a soft metal that is easy to drill out, the ball seat mechanism can be quickly drilled out by a drill bit.

[0110] It should be understood that the embodiments disclosed herein are not limited to the specific structures, processing steps, or materials disclosed herein, but should be extended to equivalent substitutions of these features as understood by those skilled in the art. It should also be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting.

[0111] In the description of this invention, unless otherwise stated, "a plurality of" means two or more; the terms "upper," "lower," "left," "right," "inner," "outer," "front end," "rear end," "head," "tail," 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 the invention 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 the invention. Furthermore, the terms "first," "second," "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0112] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0113] Certain terms are used throughout this application to refer to specific system components. As those skilled in the art will recognize, the same components may often be referred to by different names, and therefore this application is not intended to distinguish components that differ only in name and not in function. The terms "an embodiment" or "embodiment" used in the specification mean that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. Therefore, the phrase "an embodiment" or "embodiment" appearing throughout the specification does not necessarily refer to the same embodiment.

[0114] The embodiments of the present invention are given for illustrative and descriptive purposes only, and are not intended to be exhaustive or to limit the invention to the forms disclosed. Many modifications and variations will be apparent to those skilled in the art. The embodiments were chosen and described in order to better illustrate the principles and practical application of the invention, and to enable those skilled in the art to understand the invention and to design various embodiments with various modifications suitable for a particular purpose.

[0115] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and / or modifications falling within the scope of the invention, and all changes and / or modifications made according to embodiments of the invention should be covered within the protection scope of the invention.

Claims

1. A single-pass, multi-stage linkage ball seat mechanism, characterized in that, include: The outer casing (10) is connected in the column and positioned below the seat or sealing tool; as well as A segmented ball seat (20) is disposed inside the outer casing (10), the segmented ball seat (20) comprising a plurality of segmented ball seat bodies (21); The segmented ball seat (21) is arranged circumferentially, and its lower end converges toward the middle of the segmented ball seat (20) to form a cone-shaped structure, which can bear the pressure ball (30). When the pressure inside the tubing reaches a first set value, the split ball seat (21) can deform, causing the pressure-reducing ball (30) to fall out of the split ball seat (20); When the pressure inside the tubing reaches a second set value, the setting or sealing tool completes the setting or sealing under the action of the pressure, and the second set value is less than the first set value.

2. The ball seat mechanism with multi-stage linkage in one pass according to claim 1, characterized in that, The split ball seat (21) includes a connecting section (22) connected to the outer shell (10), and the outer wall of the connecting section (22) is connected to the inner wall of the outer shell (10) by a connector; The lower end of the connecting section (22) is provided with a support section (23), which is inclined toward the inside of the outer shell (10).

3. The ball seat mechanism with multi-stage linkage in one pass according to claim 2, characterized in that, The connector is a fixing bolt (13), and the split ball seat (20) is made of an easy-to-drill material.

4. The ball seat mechanism with multi-stage linkage in one pass according to claim 2, characterized in that, The pressure ball (30) is a vulcanized pressure ball.

5. The ball seat mechanism with multi-stage linkage in a single pass according to claim 3 or 4, characterized in that, The upper end of the outer shell (10) is provided with a sleeve female buckle (11), and the lower end is provided with a sleeve male buckle (12).

6. A cementing method, characterized in that, Cementing operations are carried out using a single-pass, multi-stage linkage ball seat mechanism according to any one of claims 1 to 5.

7. The cementing method according to claim 6, characterized in that, A pipe string is provided, the pipe string including, from top to bottom, a balance cylinder type tailpipe hanger, a first-stage ball seat, a restraining short section, a second-stage ball seat, a float band, and a float shoe; Wherein, at least the first-stage ball seat is a ball seat mechanism with one-pass multi-stage linkage according to any one of claims 1 to 5.

8. The cementing method according to claim 7, characterized in that, Includes the following steps: The design depth from the bottom of the tubing string to the bottom of the well is reached by dropping a pressure ball (30) above the wellhead. The pressure ball (30) is pressed by the drilling fluid to the position of the first-stage ball seat. When the pressure reaches the second set value, the balance cylinder type tailpipe hanger completes the sitting and hanging action; Continue to pressurize until the first set value is reached, and the split ball seat (20) is opened, so that the pressurized ball (30) falls to the second-level ball seat; The pressure is increased to the settling pressure of the restraining short section, causing the restraining short section to complete settling, and pressure is continued until the second-stage ball seat is vented; After the cement slurry has completely solidified, the drilling tool is lowered to remove the split ball seat (20), completing one cementing operation.

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