One-trip multi-stage linkage ball seat mechanism and well cementation method

Abstract

The invention provides a one-trip multi-stage linkage ball seat mechanism and a well cementation method, and the ball seat mechanism comprises a shell which is connected in a tubular column and is arranged below a setting hanging / setting tool; the split ball seat is arranged in the shell and comprises a plurality of split ball seat bodies; wherein the sectioning ball seat body is arranged in the circumferential direction, the lower end of the sectioning ball seat body gathers towards the middle of the sectioning ball seat to form a conical structure, and the sectioning ball seat body can bear a pressure building ball. The construction process problem that one-time pitching multi-stage setting hanging / setting action cannot be achieved on a well cementation construction site is solved, and safety and reliability of the well cementation construction process flow are guaranteed.

Description

Technical Field

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

[0002] For vertical wells constructed with one-time tubing, a sulfide metal ball of matching size is put in. Due to its own weight, the sulfide metal ball will smoothly fall into the mouth of the ball seat and cooperate with the inner conical surface of the ball seat. After the collision and pressure, the pressure of the tubing increases. When the pressure inside the pipe reaches the value designed by the cementing engineer, the packer or the tail pipe hanger can be set. Then, the pressure is continued to make the sulfide metal ball pass through the ball seat pin and fall into the bottom recovery cage, completing the construction action of the cementing tool once.

[0003] At present, the ball seat for setting the packer or liner hanger can generally only be used for one ball setting, that is, a sulfide metal ball can only complete one setting / hanging action before the ball seat is blocked. However, as more and more deep and ultra-deep wells are being developed, the increasingly complex downhole environment has put forward higher requirements for cementing tools. In order to save the cost and time of cementing engineering construction, it is often necessary to complete two sittings or even multi-stage linkage with one ball.

[0004] With the existing cementing technology, the ball seat is usually set below the cementing tools that need to be moved, such as the packer / tail pipe hanger / tie-off in the string structure, and above the cementing tool accessories that do not need to be moved, such as the floating collar and floating shoe. By adjusting the shear pressure of the pins inside different cementing tools, they are controlled to complete the set actions in sequence and in an orderly manner. However, relying on the existing method will cause the pressure of the bottom ball seat to be too high, which poses certain construction safety hazards. Summary of the invention

[0005] In view of the above-mentioned 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 the cementing construction site cannot realize the multi-stage hanging / sealing action of one-time ball throwing, and ensure the safety and reliability of the cementing construction process.

[0006] In addition, the invention also provides a well cementing method.

[0007] According to one aspect of the present invention, a one-way multi-stage linkage ball seat mechanism is proposed, comprising: a housing connected to the pipe string and disposed below the setting / sealing tool; and A petal ball seat disposed inside the housing, the petal ball seat comprising a plurality of petal ball seat bodies; The petal ball seat body is arranged along the circumferential direction, and the lower end thereof gathers toward the middle of the petal ball seat to form a conical structure, which can carry the pressure-holding ball.

[0008] A further improvement of the present invention is that when the pressure in the column reaches a first set value, the petal ball seat body can be deformed to make the pressure-holding ball fall off from the petal ball seat.

[0009] A further improvement of the present invention is that when the pressure in the tubing string reaches a second set value, the setting / sealing tool completes setting or sealing under the action of the pressure, and the second set value is smaller than the first set value.

[0010] A further improvement of the present invention is that the petal-splitting ball seat body comprises 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 through a connecting piece; A supporting section is arranged at the lower end of the connecting section, and the supporting section is arranged to be inclined toward the inner side of the shell.

[0011] A further improvement of the present invention is that the connecting piece is a fixing bolt, and the petal ball seat is made of a material that is easy to drill out.

[0012] A further improvement of the present invention is that the pressure-holding ball is a vulcanized pressure-holding ball.

[0013] A further improvement of the present invention is that a sleeve female buckle is arranged at the upper end of the shell, and a sleeve male buckle is arranged at the lower end.

[0014] According to another aspect of the present invention, a cementing method is also proposed, which uses the one-trip multi-stage linkage ball seat mechanism to perform cementing construction.

[0015] A further improvement of the present invention is to provide a pipe string, the pipe string comprising a balanced cylinder type tail pipe hanger, a first stage ball seat, a containment nipple, a second stage ball seat, a floating collar and a floating shoe arranged from top to bottom; Among them, at least the first-stage ball seat is the one-way multi-stage linkage ball seat mechanism.

[0016] A further improvement of the present invention is that the method comprises the following steps: A pressure-holding ball is dropped from the bottom of the pipe string to the designed depth of the well, and is placed above the wellhead, and the pressure-holding ball is pressed against the first-stage ball seat position along with the drilling fluid; The pressure is held at a second set value, so that the balance cylinder type liner hanger completes the sitting and hanging action; Continue to hold the pressure until the first set value is reached, and the petal ball seat is opened, so that the pressure holding ball falls to the second-level ball seat; The pressure is held down to the seating pressure of the containment sub, so that the containment sub is seated, and the pressure is continued to be held down until the second-stage ball seat is opened; After the cement slurry is completely solidified, the drilling tool is lowered to drill out the petal ball seat to complete the cementing operation.

[0017] Compared with the prior art, the present invention has the following advantages.

[0018] The one-trip multi-stage linkage ball seat mechanism described in the present invention solves the construction process problem that the cementing construction site cannot realize multi-stage hanging / sealing actions by one ball throwing, and ensures the safety and reliability of the cementing construction process.

[0019] The one-way multi-stage linkage ball seat mechanism according to the present invention has a simple structure and a scientific and reasonable design: the ball seat mechanism is composed of only four parts, and is quick and convenient to assemble, meeting the requirements of quick and simple use on site; by precisely controlling the thickness of the petal ball seat, the effect of precisely controlling the ball seat's blocking pressure is achieved.

[0020] According to the one-way multi-stage linkage ball seat mechanism of the present invention, by matching with a conventional ball seat, two-stage sitting / sealing can be realized; if two multi-stage linkage ball seats and one conventional ball seat are matched, three-stage sitting / sealing action can be realized. By analogy, if the wear on the surface of the vulcanization pressure holding ball is ignored, an unlimited number of action processes can be realized by increasing the number of stage linkage ball seats in the pipe string.

[0021] According to the one-pass multi-stage linkage ball seat mechanism of the present invention, since the inner core material is made of soft metal that is easy to drill out, the ball seat mechanism can be quickly drilled out by a drill bit. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, in which: Figure 1 The figure shows a schematic diagram of a one-way multi-stage linkage ball seat mechanism according to an embodiment of the present invention; Figure 2 The figure is a schematic structural diagram of a petal ball seat body according to an embodiment of the present invention; It should be noted that the drawings are not necessarily drawn according to actual scale.

[0023] The meanings of the reference numerals in the accompanying drawings are as follows: 10. Shell, 11. Female buckle of casing, 12. Male buckle of casing, 13. Fixing bolt, 20. Petal ball seat, 21. Petal ball seat body, 22. Connecting section, 23. Support section, 24. Bolt hole, 30. Pressure-holding ball. DETAILED DESCRIPTION

[0025] In order to make the technical solutions and advantages of the present invention more clearly understood, the exemplary embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than an exhaustive list of all the embodiments. In addition, the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

[0026] For vertical wells constructed with one-time tubing, a sulfide metal ball of matching size is put in. Due to its own weight, the sulfide metal ball will smoothly fall into the mouth of the ball seat and cooperate with the inner conical surface of the ball seat. After the collision and pressure, the pressure of the tubing increases. When the pressure inside the pipe reaches the value designed by the cementing engineer, the packer or the tail pipe hanger can be set. Then, the pressure is continued to make the sulfide metal ball pass through the ball seat pin and fall into the bottom recovery cage, completing the construction action of the cementing tool once.

[0027] At present, the ball seat for setting the packer or liner hanger can generally only be used for one ball setting, that is, a sulfide metal ball can only complete one setting / hanging action before the ball seat is blocked. However, as more and more deep and ultra-deep wells are being developed, the increasingly complex downhole environment has put forward higher requirements for cementing tools. In order to save the cost and time of cementing engineering construction, it is often necessary to complete two sittings or even multi-stage linkage with one ball.

[0028] With the existing cementing technology, the ball seat is usually set below the cementing tools that need to be moved, such as the packer / tail pipe hanger / tie-off in the string structure, and above the cementing tool accessories that do not need to be moved, such as the floating collar and floating shoe. By adjusting the shear pressure of the pins inside different cementing tools, they are controlled to complete the set actions in sequence and in an orderly manner. However, relying on the existing method will cause the pressure of the bottom ball seat to be too high, which poses certain construction safety hazards.

[0029] In such Figure 1 In the illustrated embodiment, the one-way multi-stage linkage ball seat mechanism according to the present invention comprises: The housing 10 is a cylindrical structure, connected in the pipe string and arranged below the setting / sealing tool and above the next-level ball seat. The next-level ball seat can be an ordinary ball seat or the ball seat mechanism described in this embodiment.

[0030] A petal ball seat 20 is disposed inside the housing 10, and the petal ball seat 20 includes a plurality of petal ball seat bodies 21; The petal ball seat body 21 is arranged along the circumferential direction, and the lower end thereof gathers toward the middle of the petal ball seat 20 to form a conical structure.

[0031] In this embodiment, a small hole is formed at the end of the conical structure formed at the lower end of the petal ball seat body 21, through which fluid can flow. When the pressure-holding ball 30 is put in, the pressure-holding ball 30 falls into the conical structure and blocks the small hole, separating the top and bottom of the petal ball seat 20. Under the action of the pressure in the well, the seating or sealing of the seating / sealing tool is completed, and the pressurization is continued to open the petal ball seat 20 under the action of pressure. The pressure-holding ball 30 passes through the petal ball seat 20 and falls to the next-level ball seat, or completes a cementing and falls off the bottom of the well.

[0032] In the one-trip multi-stage linkage ball seat mechanism according to the present embodiment, the outer shell 10 can be a cylindrical short section structure, which is connected to the pipe string and is arranged between the sitting / sealing tool and the ordinary ball seat. After the pressure-holding ball 30 is put into place, the pressure-holding ball 30 will fall onto the petal ball seat 20 to achieve pressure holding above the petal ball seat 20, and the sitting / sealing tool is driven under the action of pressure to complete sitting or sealing.

[0033] In one embodiment, the petal ball seat 21 has a certain supporting capacity and a certain deformation capacity. When the pressure in the column reaches a first set value, the petal ball seat 21 can deform to make the pressure holding ball 30 fall off from the petal ball seat 20 .

[0034] In a preferred embodiment, when the pressure in the tubing reaches a second set value, the seating / sealing tool completes seating or sealing under the action of the pressure, and the second set value is less than the first set value. In this way, after the pressure-holding ball 30 falls into the petal ball seat 20, the pressure in the tubing is increased by pumping pressure from the wellhead. When the pressure reaches the second set value, the seating / sealing tool is driven to complete seating or sealing under the action of the pressure, and then the pressure in the tubing is increased. When the pressure reaches the first set value, the petal ball seat 20 is deformed, causing the pressure-holding ball 30 to fall off from the petal ball seat 20.

[0035] In one embodiment, the petal ball seat body 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 through a connecting piece; A supporting section 23 is disposed at the lower end of the connecting section 22 , and the supporting section 23 is inclined toward the inner side of the housing 10 .

[0036] In the one-way multi-stage linkage ball seat mechanism according to the present embodiment, the connecting end of the petal ball seat body 21 is an arc-shaped structure, which matches the arc surface of the inner wall of the outer shell 10, and multiple petal ball seat bodies 21 are arranged side by side along the circumferential direction to form a circle.

[0037] The connecting section 22 of the split ball seat body 21 is fixedly connected to the housing 10 via a connecting piece.

[0038] The support section 23 is inclined toward the inner side of the shell 10, and the support sections 23 of the multiple petal ball seat bodies 21 are arranged side by side to form a conical structure. The multiple petal ball seat bodies 21 are arranged closely side by side, and two adjacent support sections can be connected or separated.

[0039] In one embodiment, the connecting member is a fixing bolt 13, which firmly fixes the petal ball seat 20 on the outer shell 10 so that it does not fall off with the pressure-holding ball 30. Therefore, higher requirements are placed on the steel grade of the fixing bolt 13 to ensure that the fixing bolt 13 can withstand a pressure at least above the second set value.

[0040] The petal ball seat 20 is made of a material that is easy to drill out, including but not limited to 2A12 aluminum alloy and H62 brass that are easy to drill out.

[0041] Preferably, the pressure-holding ball 30 is a vulcanized pressure-holding ball. The vulcanized pressure-holding ball is a non-connecting part and is dropped at the wellhead when the ball seat needs to be moved. The inner core of the vulcanized pressure-holding ball is a metal ball and the outer skin is vulcanized rubber. The metal ball of the inner core provides gravity and overall strength, and the vulcanized rubber on its outer surface can form a seal with the inner surface of the petal ball seat 20, thereby holding the ball seat open.

[0042] In one embodiment, a sleeve female buckle 11 is disposed at the upper end of the housing 10 , and a sleeve male buckle 12 is disposed at the lower end of the housing 10 .

[0043] In this embodiment, the housing 10 of the ball seat mechanism can be adaptively matched according to the buckle type and specification size of the casing string, so the ball seat mechanism can adapt to casings of all specifications and types.

[0044] The one-way multi-stage linkage ball seat mechanism described in this embodiment has a simple structure and a scientific and reasonable design: the ball seat mechanism is composed of only four parts, and is quick and convenient to assemble, meeting the requirements of quick and simple use on site; by precisely controlling the thickness of the petal ball seat 20, the effect of precisely controlling the ball seat's blocking pressure is achieved.

[0045] According to another aspect of the present invention, a cementing method is also proposed, wherein the method uses the one-trip multi-stage linkage ball seat mechanism described in the above embodiment to perform cementing construction.

[0046] The method includes proposing a pipe string, the pipe string includes a setting / sealing tool, such as a balanced liquid cylinder type liner hanger, a check nipple, etc. In this embodiment, the balanced liquid cylinder type liner hanger is arranged on the pipe column, and a first-stage ball seat is arranged below the balanced liquid cylinder type liner hanger, and the first-stage ball seat is a one-trip multi-stage linkage ball seat mechanism described in the present invention; a check nipple is arranged below the first-stage ball seat, and a second-stage ball seat is arranged below the check nipple. In this embodiment, the second-stage ball seat is an ordinary ball seat. Of course, the one-trip multi-stage linkage ball seat mechanism can also be selected according to actual needs. A floating collar and a floating shoe are arranged below the second-stage ball seat.

[0047] In this embodiment, more stages of setting / sealing tools and ball seats may be added to the pipe string according to actual conditions.

[0048] According to the method described in this embodiment, a one-way multi-stage linkage ball seat mechanism is used in combination with a conventional ball seat to achieve two-stage seating / sealing; if two multi-stage linkage ball seats are matched with a conventional ball seat, a three-stage seating / sealing action can be achieved. By analogy, if the wear on the surface of the vulcanization pressure holding ball is ignored, an unlimited number of action processes can be achieved by increasing the number of stage linkage ball seats in the pipe string.

[0049] In one embodiment, the method comprises the following steps: A pressure holding ball 30 is dropped from the bottom of the pipe string to the designed depth of the well, and is placed above the wellhead. The pressure holding ball 30 is pressed against the first-stage ball seat position along with the drilling fluid. The pressure is held at a second set value, so that the balance cylinder type liner hanger completes the sitting and hanging action; Continue to hold the pressure until the first set value is reached, and the petal ball seat 20 is opened, so that the holding pressure ball 30 falls to the second-level ball seat; The pressure is held down to the seating pressure of the containment sub, so that the containment sub is seated, and the pressure is continued to be held down until the second-stage ball seat is opened; After the cement slurry is completely solidified, the drilling tool is lowered to drill out the petal ball seat 20, thus completing a cementing operation.

[0050] According to the method described in this embodiment, it solves the construction process problem that the cementing construction site cannot realize multi-stage hanging / sealing actions by one ball throwing, and ensures the safety and reliability of the cementing construction process.

[0051] According to the one-pass multi-stage linkage ball seat mechanism of the present invention, since the inner core material is made of soft metal that is easy to drill out, the ball seat mechanism can be quickly drilled out by a drill bit.

[0052] The following describes it in conjunction with specific embodiments.

[0053] Example 1 One-way multi-stage linkage ball seat mechanism, including: The housing 10 is connected in the pipe string and arranged below the setting / sealing tool and above the next-stage ball seat.

[0054] A petal ball seat 20 is disposed inside the housing 10, and the petal ball seat 20 includes a plurality of petal ball seat bodies 21; The petal ball seat body 21 is arranged along the circumferential direction, and the lower end thereof gathers toward the middle of the petal ball seat 20 to form a conical structure.

[0055] A small hole is formed at the end of the conical structure formed at the lower end of the petal ball seat body 21, through which fluid can flow. When the pressure-holding ball 30 is put in, the pressure-holding ball 30 falls into the conical structure and blocks the small hole, separating the top and bottom of the petal ball seat 20. The seating or sealing of the seating / sealing tool is completed under the action of the well pressure. The pressurization is continued, and the petal ball seat 20 is opened under the action of pressure. The pressure-holding ball 30 passes through the petal ball seat 20 and falls to the next-level ball seat, or completes a cementing and falls off the bottom of the well.

[0056] The petal ball seat 21 has a certain supporting capacity and a certain deformation capacity. When the pressure in the column reaches a first set value, the petal ball seat 21 can be deformed to make the pressure holding ball 30 fall off from the petal ball seat 20 .

[0057] When the pressure in the tubing reaches a second set value, the seating / sealing tool completes seating or sealing under the action of the pressure, and the second set value is less than the first set value. In this way, after the pressure-holding ball 30 falls into the petal ball seat 20, the pressure in the tubing is increased from the wellhead to reach the second set value, and the seating / sealing tool is driven to complete seating or sealing under the action of the pressure, and then the pressure in the tubing is increased to reach the first set value, so that the petal ball seat 20 is deformed, and the pressure-holding ball 30 falls off from the petal ball seat 20.

[0058] The petal ball seat body 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 through fixing bolts 13; a supporting section 23 is provided at the lower end of the connecting section 22, and the supporting section 23 is inclined toward the inner side of the outer shell 10.

[0059] The connecting end of the petal ball seat body 21 is a curved surface structure, matching the curved surface of the inner wall of the housing 10. A plurality of petal ball seats 21 are arranged side by side along the circumference to form a circle. The connecting section 22 of the petal ball seat body 21 is fixedly connected to the housing 10 through a connecting piece.

[0060] The support section 23 is arranged to be inclined toward the inner side of the housing 10 , and the support sections 23 of the plurality of petal ball seat bodies 21 are arranged side by side to form a conical structure, and the plurality of petal ball seat bodies 21 are arranged side by side and closely attached to each other.

[0061] The petal ball seat 20 is made of a material that is easy to drill out, such as 2A12 aluminum alloy.

[0062] The pressure holding ball 30 is a vulcanized pressure holding ball. The vulcanized pressure holding ball is a non-connecting part and is dropped at the wellhead when the ball seat needs to be moved. The inner core of the vulcanized pressure holding ball is a metal ball and the outer skin is vulcanized rubber. The metal ball of the inner core provides gravity and overall strength, and the vulcanized rubber on its outer surface can form a seal with the inner surface of the petal ball seat 20, thereby holding the ball seat open.

[0063] The upper end of the housing 10 is provided with a sleeve female buckle 11 , and the lower end of the housing 10 is provided with a sleeve male buckle 12 .

[0064] Example 2 The one-way multi-stage linkage ball seat mechanism comprises: a housing 10 connected in the pipe string and arranged below the setting / sealing tool and above the next stage ball seat. A petal ball seat 20 arranged inside the housing 10, the petal ball seat 20 comprises a plurality of petal ball seat bodies 21; wherein the petal ball seat bodies 21 are arranged along the circumferential direction, and their lower ends gather toward the middle of the petal ball seat 20 to form a tapered structure.

[0065] A small hole is formed at the end of the conical structure formed at the lower end of the petal ball seat body 21, through which fluid can flow. When the pressure-holding ball 30 is put in, the pressure-holding ball 30 falls into the conical structure and blocks the small hole, separating the top and bottom of the petal ball seat 20. The seating or sealing of the seating / sealing tool is completed under the action of the well pressure. The pressurization is continued, and the petal ball seat 20 is opened under the action of pressure. The pressure-holding ball 30 passes through the petal ball seat 20 and falls to the next-level ball seat, or completes a cementing and falls off the bottom of the well.

[0066] The petal ball seat 21 has a certain supporting capacity and a certain deformation capacity. When the pressure in the column reaches a first set value, the petal ball seat 21 can be deformed to make the pressure holding ball 30 fall off from the petal ball seat 20 .

[0067] When the pressure in the tubing reaches a second set value, the seating / sealing tool completes seating or sealing under the action of the pressure, and the second set value is less than the first set value. In this way, after the pressure-holding ball 30 falls into the petal ball seat 20, the pressure in the tubing is increased from the wellhead to reach the second set value, and the seating / sealing tool is driven to complete seating or sealing under the action of the pressure, and then the pressure in the tubing is increased to reach the first set value, so that the petal ball seat 20 is deformed, and the pressure-holding ball 30 falls off from the petal ball seat 20.

[0068] The petal ball seat body 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 through fixing bolts 13; a supporting section 23 is provided at the lower end of the connecting section 22, and the supporting section 23 is inclined toward the inner side of the outer shell 10.

[0069] The connecting end of the petal ball seat body 21 is a curved surface structure, matching the curved surface of the inner wall of the housing 10. A plurality of petal ball seats 21 are arranged side by side along the circumference to form a circle. The connecting section 22 of the petal ball seat body 21 is fixedly connected to the housing 10 through a connecting piece.

[0070] The support section 23 is arranged to be inclined toward the inner side of the housing 10 , and the support sections 23 of the plurality of petal ball seat bodies 21 are arranged side by side to form a conical structure, and the plurality of petal ball seat bodies 21 are arranged side by side and closely attached to each other.

[0071] In this embodiment, the petal ball seat 20 is made of H62 brass, and the other structures are the same as those in the first embodiment.

[0072] Example 3 A pipe string, the pipe string comprising a hanging / sealing tool, such as a balanced liquid cylinder type liner hanger, a check pup joint, etc. In the present embodiment, the balanced liquid cylinder type liner hanger is arranged on the pipe column, and a first-stage ball seat is arranged below the liner hanger, and the first-stage ball seat is the one-trip multi-stage linkage ball seat mechanism described in Example 1 or Example 2; a check pup joint is arranged below the first-stage ball seat, and a second-stage ball seat is arranged below the check pup joint, and in the present embodiment, the second-stage ball seat is an ordinary ball seat.

[0073] Example 4 A pipe string comprises three sets of seating / sealing tools and three-stage ball seats, wherein the first-stage ball seat and the second-stage ball seat are both the one-trip multi-stage linkage ball seat mechanism described in the present invention, and the third-stage ball seat is an ordinary ball seat.

[0074] Example 5 A cementing method, the method comprising the following steps: A pressure holding ball 30 is dropped from the bottom of the pipe string to the designed depth of the well, and is placed above the wellhead. The pressure holding ball 30 is pressed against the first-stage ball seat position along with the drilling fluid. The pressure is held at a second set value, so that the balance cylinder type liner hanger completes the sitting and hanging action; Continue to hold the pressure until the first set value is reached, and the petal ball seat 20 is opened, so that the holding pressure ball 30 falls to the second-level ball seat; The pressure is held down to the seating pressure of the containment sub, so that the containment sub is seated, and the pressure is continued to be held down until the second-stage ball seat is opened; After the cement slurry is completely solidified, the drilling tool is lowered to drill out the petal ball seat 20, thus completing a cementing operation.

[0075] According to the method described in this embodiment, it solves the construction process problem that the cementing construction site cannot realize multi-stage hanging / sealing actions by one ball throwing, and ensures the safety and reliability of the cementing construction process.

[0076] According to the one-pass multi-stage linkage ball seat mechanism of the present invention, since the inner core material is made of soft metal that is easy to drill out, the ball seat mechanism can be quickly drilled out by a drill bit.

[0077] It should be understood that the embodiments disclosed in the present invention are not limited to the specific structures, processing steps or materials disclosed herein, but should be extended to equivalent substitutions of these features understood by ordinary technicians in the relevant field. It should also be understood that the terms used herein are only used for the purpose of describing specific embodiments and are not meant to be limiting.

[0078] In the description of the present invention, unless otherwise specified, "plurality" means two or more than two; the orientations or positional relationships indicated by the terms "upper", "lower", "left", "right", "inner", "outer", "front end", "rear end", "head", "tail", etc. are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", "third", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0079] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0080] Certain terms are used throughout this specification to refer to specific system components. As will be appreciated by those skilled in the art, different names may be used to refer to the same component, and thus this specification is not intended to distinguish between components that differ only in name and not in function. References to "one embodiment" or "an embodiment" in the specification mean that a particular feature, structure, or characteristic described in conjunction with the embodiment is included in at least one embodiment of the invention. Therefore, the phrases "one embodiment" or "an embodiment" appearing in various places throughout the specification do not necessarily all refer to the same embodiment.

[0081] The embodiments of the present invention are given for the purpose of illustration and description, and are not intended to be exhaustive or to limit the invention to the disclosed forms. Many modifications and variations will be apparent to those of ordinary skill in the art. The embodiments are selected and described in order to better illustrate the principles and practical applications of the present invention and to enable those of ordinary skill in the art to understand the present invention and thereby design various embodiments with various modifications suitable for specific uses.

[0082] Although the preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they are aware of the basic creative concepts. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and / or modifications that fall within the scope of the present invention, and changes and / or modifications made according to the embodiments of the present invention should be included within the scope of protection of the present invention.

Claims

1. A one-way multi-stage linkage ball seat mechanism, characterized in that: include: A housing (10) connected to the pipe string and arranged below the setting / sealing tool; as well as A petal ball seat (20) disposed inside the housing (10), the petal ball seat (20) comprising a plurality of petal ball seat bodies (21); The petal ball seat body (21) is arranged along the circumferential direction, and its lower end is gathered toward the middle of the petal ball seat (20) to form a conical structure, which can carry the pressure-holding ball (30).

2. The one-way multi-stage linkage ball seat mechanism according to claim 1, characterized in that: When the pressure in the pipe column reaches a first set value, the petal ball seat body (21) can be deformed, causing the pressure-holding ball (30) to fall off from the petal ball seat (20).

3. The one-way multi-stage linkage ball seat mechanism according to claim 2, characterized in that: When the pressure in the tubing string reaches a second set value, the setting / sealing tool completes setting or sealing under the action of the pressure, and the second set value is less than the first set value.

4. The one-way multi-stage linkage ball seat mechanism according to claim 3, characterized in that: The petal ball seat body (21) comprises 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) via a connecting piece; A supporting section (23) is provided at the lower end of the connecting section (22), and the supporting section (23) is arranged to be inclined towards the inner side of the outer shell (10).

5. The one-way multi-stage linkage ball seat mechanism according to claim 4, characterized in that: The connecting piece is a fixing bolt (13), and the petal ball seat (20) is made of a material that is easy to drill out.

6. The one-way multi-stage linkage ball seat mechanism according to claim 4, characterized in that: The pressure holding ball (30) is a vulcanized pressure holding ball.

7. The one-way multi-stage linkage ball seat mechanism according to claim 5 or 6, characterized in that: The upper end of the housing (10) is provided with a sleeve female buckle (11), and the lower end is provided with a sleeve male buckle (12).

8. A cementing method, characterized in that: Cementing construction is carried out using the one-trip multi-stage linkage ball seat mechanism according to any one of claims 1 to 7.

9. The cementing method according to claim 8, characterized in that: Provided is a pipe string, the pipe string comprising a balanced hydraulic cylinder type tail pipe hanger, a first-stage ball seat, a containment nipple, a second-stage ball seat, a floating collar and a floating shoe arranged from top to bottom; Among them, at least the first-stage ball seat is a one-way multi-stage linkage ball seat mechanism according to any one of claims 1 to 7.

10. The cementing method according to claim 9, characterized in that: The following steps are involved: A pressure-holding ball (30) is dropped above the wellhead from the bottom of the pipe string to the designed depth of the well, and the pressure-holding ball (30) is pressed against the first-stage ball seat position along with the drilling fluid; The pressure is held at a second set value, so that the balance cylinder type liner hanger completes the sitting and hanging action; Continue to hold the pressure until the first set value is reached, and the petal ball seat (20) is opened, so that the holding pressure ball (30) falls to the second-level ball seat; The pressure is held down to the seating pressure of the containment sub, so that the containment sub is seated, and the pressure is continued to be held down until the second-stage ball seat is opened; After the cement slurry is completely solidified, the drilling tool is lowered to drill out the petal ball seat (20), thereby completing a cementing operation.

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