Graded cementing device, graded cementing well cementation device, graded cementing well cementation system and application of graded cementing well cementation device and graded cementing well cementation system

Abstract

The invention discloses a graded cementing device, a graded cementing well cementation device, a graded cementing well cementation system and application. The graded cementing device comprises a body, a first shell, a second shell, an opening sleeve, an opening ring and a piston, a first through hole is formed in the sleeve wall of the opening sleeve, the opening ring is embedded in the opening sleeve, and the opening ring covers the first through hole and is connected with the opening sleeve through a first pin; the opening sleeve is embedded in the body and the first shell, the opening sleeve is connected with the body through a second pin, a fluid channel communicated with the first through hole is formed between the opening sleeve and the first shell, and the fluid channel is communicated with a first cavity defined by the first shell; the second shell is used for being matched with a central pipe of the packer, a second cavity for containing the piston is formed between the second shell and the central pipe, and the piston is connected with the second shell through a third pin; the cementing device has the advantages that the operation is reliable, the operation delay is reduced, and the construction operation cost is reduced.

Description

Technical Field

[0001] This invention relates to the field of cementing tools for oil and gas fields, and particularly to a staged cementing injector, a cementing device, system, and application for staged cementing. Background Technology

[0002] With the development and application of highly deviated and horizontal wells into deeper formations, downhole complexities have become more prominent, posing greater challenges and difficulties to cementing technology. During cementing operations, excessively long cementing sections in a single operation lead to excessively high pressure differentials; cementing low-pressure, easily leaky wells can easily cause cementing losses; simultaneously, excessively long single-stage cementing sections result in large temperature differences between the upper and lower sections, making it difficult for cement performance to meet cementing requirements; uneven and discontinuous oil and gas distribution with excessively long intervals in between. These factors have spurred the development of staged cementing tools and related processes. However, existing staged cementing tools have some design shortcomings: the gas-tightness of the staged couplings may be low, making them susceptible to the pressure of the casing annulus; due to changes in wellbore pressure, the staged couplings may not set correctly or may set prematurely; the complex design of the staged coupling structure may require the removal of too many drilled components during the design process. Summary of the Invention

[0003] To improve the reliability of cementing operations, reduce operation delays, lower costs, and address issues such as deep wells, long open-hole sections, multiple oil, gas and water show layers, low formation pressure capacity, and easy leakage, this invention provides a staged cementing device, a staged cementing apparatus, a system, and its application, applicable to various well types such as highly deviated wells and horizontal wells, in order to further ensure cementing quality and meet the requirements of different well types.

[0004] In a first aspect, embodiments of the present invention provide a graded cement injector, which may include: a body, an opening sleeve, an opening ring, a first housing, a second housing, and a piston; the body, the first housing, and the second housing are connected in sequence.

[0005] The opening sleeve has a first through hole on its wall. An opening ring is embedded inside the opening sleeve, covering the first through hole and connected to the opening sleeve via a first pin. The opening sleeve is embedded inside the body and the first housing, and is connected to the body via a second pin. A fluid channel communicating with the first through hole is formed between the opening sleeve and the first housing, and the fluid channel communicates with a first chamber enclosed by the first housing. The second housing is used to cooperate with the central tube of the packer. A second chamber accommodating the piston is formed between the second housing and the central tube, and the piston is connected to the second housing via a third pin. The first chamber and the second chamber communicate with each other.

[0006] The opening plug, which is used to cooperate with the opening ring, is pumped into the staged cement injector to pressurize and shear the first pin. The working fluid acts on the piston through the first through hole, the fluid channel, the first chamber and the second chamber and shears the third pin to achieve the setting of the external packer.

[0007] The main body has a second through hole that connects the inside and outside of the main body; in the first state, the opening sleeve covers the second through hole; in the second state, the second pin is sheared under pressure and the opening sleeve moves so that the working fluid is injected through the second through hole into the annulus between the staged cementing device and the casing to achieve cementing.

[0008] In one embodiment, the above-mentioned graded cement injector may further include: an opening end ring located inside the opening sleeve and at a first preset distance from the opening ring, the opening end ring being connected to the opening sleeve and used to limit the opening ring.

[0009] In another embodiment, the above-mentioned graded cement injector may further include: a closing sleeve and a closing end ring nested inside the closing sleeve; the closing end ring is limited by the opening sleeve and is used to cooperate with the closing plug;

[0010] At least a portion of the closing sleeve is located between the body and the opening sleeve. The closing sleeve is connected to the body via a fourth pin. A third through hole is provided on the wall of the closing sleeve, which communicates with the second through hole. The closing plug is pumped into the graded cement injector to pressurize and shear the fourth pin, causing the third through hole and the second through hole on the closing sleeve to be misaligned, thereby closing the second through hole.

[0011] In another embodiment, the above-mentioned graded cement injector may further include: a housing seat located inside the first housing and at a second preset distance from the opening sleeve and limiting the opening sleeve; the housing seat is connected to the first housing, or the housing seat is formed by extending the first housing.

[0012] In another embodiment, the opening ring is provided with a step, which is used to cooperate with the opening plug.

[0013] In another embodiment, the first housing has a fourth through hole communicating with the first chamber, and a check valve is provided in the fourth through hole.

[0014] In another embodiment, the above-described graded cement injector may further include: an upper connector; the upper connector being connected to the body.

[0015] In a second aspect, embodiments of the present invention provide a cementing device for staged cementing, which may include: a packer and a staged cementing injector as described in the first aspect;

[0016] The central tube of the packer is connected to the second housing in the staged cement injector, and the central tube and the second housing form a second chamber for accommodating the piston in the staged cement injector.

[0017] In another embodiment, the packer may include: a central tube, and an inner wedge ring, a pressure ring, a rubber sleeve, a first wedge ring, a slip, and a second wedge ring sequentially sleeved on the outside of the central tube; a portion of the pressure ring wraps around the outside of the inner wedge ring; the inner wedge ring and the pressure ring abut against the piston.

[0018] In another embodiment, the above-described cementing device may further include: a lower connector; the lower connector is connected to the center tube of the packer and engages with the second wedge ring of the packer.

[0019] Thirdly, embodiments of the present invention provide a cementing system for staged cementing, which may include: a fluid supply pipeline and a cementing device for staged cementing as described in the second aspect, wherein the fluid supply pipeline is connected to the upper connector of the staged cementing injector in the cementing device.

[0020] Fourthly, embodiments of the present invention provide an application of the staged cementing device described in the first aspect in a cementing system.

[0021] Fifthly, embodiments of the present invention provide an application of the staged cementing cementing device as described in the second aspect in a cementing system.

[0022] The beneficial effects of the above-mentioned technical solutions provided in the embodiments of the present invention include at least the following:

[0023] This invention provides a staged cementing injector, a cementing device for staged cementing, a system, and its application. This staged cementing injector uses a mature setting method to set the injector during staged cementing operations, ensuring reliable operation, reducing operational delays, and thus lowering construction costs. Compared to existing staged cementing injectors, this injector removes less material and components, facilitating simplified, economical, and reliable staged cementing.

[0024] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the written description and the accompanying drawings.

[0025] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0026] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0027] Figure 1 This is a schematic diagram of the structure of the graded cement injector provided in an embodiment of the present invention;

[0028] Figure 2 This is a schematic diagram of the staged cement injector in the open state provided in an embodiment of the present invention;

[0029] Figure 3 This is a schematic diagram of the cementing device for staged cementing provided in an embodiment of the present invention;

[0030] Figure 4 This is a schematic diagram of the cementing device for staged cementing in the open state provided in an embodiment of the present invention;

[0031] Figure 5 This is a schematic diagram of the set-sealing state of the cementing device for staged cementing provided in an embodiment of the present invention;

[0032] Figure 6 This is a schematic diagram of the cementing device for staged cementing provided in an embodiment of the present invention at the cementing completion state.

[0033] Figure 7 This is a schematic diagram of the cementing device for staged cementing in the closed state provided in an embodiment of the present invention;

[0034] Among them, 1-stage cement injector; 2-packer; 3-opening plug; 4-closing plug; 5-sleeve;

[0035] 101-Body; 102-Opening sleeve; 103-Opening ring; 104-First housing; 105-Second housing; 106-Piston; 107-First through hole; 108-First pin; 109-Second pin; 110-Fluid passage; 111-First chamber; 112-Second chamber; 113-Third pin; 114-Second through hole; 115-Opening end ring; 116-Closing sleeve; 117-Closing end ring; 118-Fourth pin; 119-Third through hole; 120-Housing seat; 121-Ladder platform; 122-Fourth through hole; 123-Check valve; 124-Upper connector;

[0036] 21-Central tube; 22-Inner wedge ring; 23-Pressure ring; 24-Rubber sleeve; 25-First wedge ring; 26-Clip; 27-Second wedge ring; 28-Lower connector. Detailed Implementation

[0037] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0038] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," "outer," "far," "near," "front," and "rear," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this 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 this invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0039] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" 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; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0040] This invention provides a staged cement injector, referring to... Figures 1-2As shown, the graded cement injector 1 may include: a body 101, an opening sleeve 102, an opening ring 103, a first housing 104, a second housing 105, and a piston 106; the body 101, the first housing 104, and the second housing 105 are connected in sequence; a first through hole 107 is provided on the wall of the opening sleeve 102, the opening ring 103 is embedded inside the opening sleeve 102, the opening ring 103 covers the first through hole 107 and is connected to the opening sleeve 102 by a first pin 108; the opening sleeve 102 is embedded inside the body 101 and the first housing 104, and the opening sleeve 102 is connected to the body 101 by a second pin 109; a fluid channel 110 is formed between the opening sleeve 102 and the first housing 104, communicating with the first through hole 107, and the fluid channel 110 communicates with the first chamber 111 enclosed by the first housing 104; the second housing 105 is used to connect with the central tube 21 of the packer 2. The second chamber 112, which accommodates the piston 106, is formed between the second housing 105 and the central tube 21, and the piston 106 is connected to the second housing 105 by a third pin 113; the first chamber 111 and the second chamber 112 are connected; the opening plug 3, which cooperates with the opening ring 103, is pumped into the staged cement injector 1 to pressurize and shear the first pin 108; the working fluid acts on the piston 106 through the first through hole 107, the fluid channel 110, the first chamber 111 and the second chamber 112 and shears the third pin 113 to achieve the setting of the external packer 2; the body 101 is provided with a second through hole 114 that connects the inside and outside of the body 101; in the first state, the opening sleeve 102 covers the second through hole 114; in the second state, the second pin 109 is pressed to shear the opening sleeve 102 to move so that the working fluid is injected into the annulus between the staged cement injector 1 and the casing 5 through the second through hole 114 to achieve cementing.

[0041] In this embodiment of the invention, the main body 101, the first housing 104, and the second housing 105 can be sequentially connected by threads. It should be noted that the second pin 109 extends to the outer surface of the main body 101, and the third pin 113 extends to the outer surface of the second housing 105. Both the second pin 109 and the third pin 113 can be easily adjusted from the outside of the graded cement injector 1, thereby adjusting the shear pressure (shear strength) of the second pin 109 and the third pin 113. Furthermore, in this embodiment of the invention, the shear strength of the second pin 109 is higher than that of the first pin 108, and the shear strength of the third pin 113 is higher than that of the first pin 108.

[0042] Combination Figures 1 to 7As shown, the working principle of the staged cement injector in this embodiment of the invention is as follows: After the staged cement injector 1 is lowered into the wellbore, the opening plug 3 is deployed and falls onto the opening ring 103. The opening plug 3 is pressurized under primary pressure using working fluid, and the pressure shears off the first pin 108, referring to... Figure 2 and Figure 4 As shown, the opening ring 103 moves to open the first through hole 107 that was previously closed by the opening ring 103. Since no shearing fastener is provided at the first through hole 107, the working fluid enters the first chamber 111 and the second chamber 112 through the fluid channel 110 via the first through hole 107. The working fluid acts on the piston 106 in the second chamber 112. After reaching a certain pressure (secondary pressure, and the secondary pressure is greater than the primary pressure mentioned above), the third pin 113 between the piston 106 and the second housing 105 is sheared, and the piston 116 pushes the connected packer 2 to achieve setting.

[0043] After the packer 2 is set, the working fluid continues to pressurize the opening plug 3 under the action of the third-level pressure (greater than the second-level pressure), as per reference. Figure 5 As shown, the opening sleeve 102 moves to open the first through hole 107, and the working fluid flows outward through the second through hole 114 into the annulus between the staged cementing machine 1 and the casing 5 to achieve cementing.

[0044] The staged cementing device provided in this embodiment of the invention uses a mature setting method to set the staged cementing device during staged cementing operations, ensuring reliable operation, reducing operation delays, and thus lowering construction costs. Compared with existing staged cementing devices, this staged cementing device removes less material and components, thereby facilitating simplified, economical, and reliable staged cementing.

[0045] In an optional embodiment, refer to Figures 1 to 7As shown, the graded cement injector 1 may further include: an opening end ring 115 located inside the opening sleeve 102 and at a first preset distance from the opening ring 103. The opening end ring 115 is connected to the opening sleeve 102 and is used to limit the opening ring 103. In this embodiment, the opening plug 3 is pressurized under a first-level pressure using working fluid. After the pressure shears off the first pin 108, the opening ring 103 moves to open the first through hole 107 covered by the opening ring 103. The opening ring 103 continues to move a first preset distance and then abuts against the opening end ring 115. Under the secondary pressure, the working fluid continues to pressurize the opening plug 3. Since the opening end ring 115 restricts the stroke of the opening ring 103, the opening plug 3, opening sleeve 102, opening ring 103 and opening end ring 115 are no longer moving. The working fluid enters the first chamber 111 and the second chamber 112 through the fluid channel 110 via the first through hole 107. Under the secondary pressure, the working fluid exerts force on the piston 106 in the second chamber 112, shearing the third pin 113 between the piston 106 and the second housing 105, so that the packer 2 that cooperates with the piston 106 is seated, thereby improving the sealing level of the staged cement injector 1.

[0046] In another alternative embodiment, refer to Figures 1 to 7 As shown, the graded cement injector 1 may further include: a closing sleeve 116 and a closing end ring 117 nested inside the closing sleeve 116; the closing end ring 117 is limited by the opening sleeve 102 and is used to cooperate with the closing plug 4; at least a portion of the closing sleeve 116 is located between the body 101 and the opening sleeve 102, and the closing sleeve 116 is connected to the body 101 by a fourth pin 118; a third through hole 119 is provided on the cylinder wall of the closing sleeve 116, which cooperates with and communicates with the second through hole 114; the closing plug 4 is pumped into the graded cement injector 1 and pressurizes to shear the fourth pin 118 so that the third through hole 119 and the second through hole 114 on the closing sleeve 116 are misaligned, so that the closing sleeve 116 closes the second through hole 114.

[0047] In this embodiment of the invention, the fourth pin 118 is designed to extend to the outer surface of the body 101, which can be easily adjusted from the outside of the graded cement injector 1, thereby adjusting the shear pressure (shear strength) of the fourth pin 118. It should be further noted that in this embodiment, the shear strength of the fourth pin 118 is higher than that of the second pin 109.

[0048] The working principle of the closing sleeve 116 in this embodiment is as follows: In the initial state (before well entry) or during the cementing process, the third through hole 119 on the closing sleeve 116 and the second through hole 114 on the body 101 are in a connected state. After the opening sleeve 102 moves, the working fluid is injected into the annulus between the stage cementing device 1 and the casing 5 through the third through hole 119 and the second through hole 114. After the stage cementing operation is completed, refer to... Figure 6 and Figure 7 As shown, the shut-off plug 4 is pumped downhole and abuts against the shut-off end ring 117 (a ladder structure can be provided on the shut-off end ring in this embodiment to further facilitate force application and sealing). Under the fourth pressure (greater than the third pressure), force is applied to the shut-off plug 4 and the fourth pin 118 connecting the shut-off sleeve 116 and the body 101 is cut off. The shut-off plug 4 drives the shut-off sleeve 116 to move, causing the third through hole 119 and the second through hole 114 to be misaligned, and finally the shut-off sleeve 116 closes the second through hole 114.

[0049] In this embodiment, the closing end ring 117 connected to the closing sleeve 116 is not only used to match the closing plug, but also to limit the stroke of the closing sleeve 116 to prevent the closing sleeve 116 from moving without restriction. After the closing end ring 117 abuts against the opening sleeve 102, the closing sleeve 116 no longer moves.

[0050] In another alternative embodiment, refer to Figures 1 to 7 As shown, the aforementioned graded cement injector 1 may further include: a housing seat 120 located inside the first housing 104 and at a second preset distance from the opening sleeve 102, which limits the opening sleeve 102; the housing seat 120 is connected to the first housing 104, or the housing seat 120 is an extension of the first housing 104. In this embodiment, the housing seat 120 limits the opening sleeve 102, preventing it from moving without restriction. It should be noted that in this embodiment, the second preset distance is greater than the length of the upper part of the opening sleeve 102 after it covers the second through hole 114, thus ensuring that the second through hole 114 can be opened after the opening sleeve 102 moves the second preset distance.

[0051] In another alternative embodiment, refer to Figures 1 to 7 As shown, the opening ring 103 is provided with a step 121, which is used to cooperate with the opening plug 3. In this embodiment, the step 121 is designed to facilitate cooperation with the opening plug 3. The step structure enables the opening plug 3 to be stably connected with the opening ring 103. At the same time, the step structure can also completely seal the upper part of the opening plug 3, so as to enable the working fluid to pressurize the opening plug 103.

[0052] In another embodiment, refer to Figures 1 to 7As shown, the first housing 104 has a fourth through hole 122 that communicates with the first chamber 111, and a check valve 123 is provided in the fourth through hole 122.

[0053] In this embodiment, the purpose of designing a fourth through hole 122 on the first housing 104 and adding a check valve 123 is to increase the setting pressure, thereby improving the sealing performance of the entire staged cement injector 1. Its working principle is as follows: After the working fluid is injected into the annulus between the staged cement injector 1 and the sleeve 5 through the second through hole 114, the working fluid can flow from the annulus into the fourth through hole 122, and then into the first chamber 111 through the check valve 123. Specifically, when the secondary pressure cannot completely set the packer 2, the working fluid operating at the tertiary pressure further pressurizes the piston 106 through the fourth through hole 122, the first chamber 111, and the second chamber 112, making the slips in the packer 2 more tightly engaged with the sleeve 5, and further compressing the rubber sleeve in the packer 2 to achieve a more stable seal with the sleeve 5.

[0054] It should be noted that the check valve 123 in this embodiment can only be opened under three levels of pressure. The fourth through-hole 122 and check valve 123, as designed above, provide more setting pressure for the staged cement injector 1, thus achieving a more stable seal. Furthermore, it should be noted that the working fluid injected during the setting process is not cementing fluid. After setting is achieved, the working fluid is drained and cementing fluid is re-injected. The cementing fluid is injected through the second through-hole 114 into the annulus between the staged cement injector 1 and the casing 5 to perform cementing operations.

[0055] In another alternative embodiment, refer to Figures 1 to 7 As shown, the aforementioned staged cement injector 1 may further include: an upper connector 124; the upper connector 124 is connected to the body 101. In this embodiment, the upper connector 124 facilitates the connection between the staged cement injector 1 and the well access pipeline during use.

[0056] The purpose of the above-mentioned staged cementing device in the embodiments of the present invention is to overcome the shortcomings of the prior art, improve the reliability of operation, reduce operation delays, reduce costs, solve the problems of deep wells, long open hole sections, multiple oil, gas and water show layers, low formation pressure capacity, easy leakage, and difficulty in ensuring cementing quality, reduce operation time, save material costs, and be applicable to various well types such as highly deviated wells and horizontal wells.

[0057] Based on the same inventive concept, this invention also provides a cementing device for staged cementing, referring to... Figures 3-7As shown, the cementing device may include a packer 2 and the aforementioned staged cement injector 1; the central tube 21 of the packer 2 is connected to the second housing 105 of the staged cement injector 1, and the central tube 21 and the second housing 105 form a second chamber 112 to accommodate the piston 106 in the staged cement injector 1. In this embodiment, the cementing device sets the packer 2 in the working section and injects cementing fluid through the staged cement injector 1 to achieve cementing operations, thereby achieving staged cementing through the cooperation of the two.

[0058] In another alternative embodiment, refer to Figures 3-7 As shown, the packer 2 may include: a central tube 21, and an inner wedge ring 22, a pressure ring 23, a rubber sleeve 24, a first wedge ring 25, a slip 26, and a second wedge ring 27 sequentially sleeved on the outside of the central tube 21; a portion of the pressure ring 23 is wrapped around the outside of the inner wedge ring 22; the inner wedge ring 22 and the pressure ring 23 are used to cooperate with the piston 106.

[0059] The setting principle of the packer 2 is as follows: The piston 106 moves and abuts against the inner wedge ring 22 and the pressure ring 23, pushing the inner wedge ring 22 and the pressure ring 23 to continue moving, thereby compressing the rubber sleeve 24 and causing it to move. The rubber sleeve 24 pushes the first wedge ring 25 to move and together with the second wedge ring 27 pushes the slip 26 to move radially outward, so that the slip 26 engages with the casing 5. The piston 106 continues to apply pressure, and the rubber sleeve 24 expands and abuts against the casing 5 to achieve setting of the cementing device.

[0060] It should be noted that, in this embodiment, the inner wedge ring 22 and the pressure ring 23 can abut against the piston 106, or a certain gap can be reserved between them. Furthermore, to save space in the overall cementing device, in this embodiment, it is preferable that the inner wedge ring 22 and the pressure ring 23 abut against the piston 106; even further, it should be noted that, in the abutment state of the components, the inner wedge ring 22 and the pressure ring 23 are not subjected to force, i.e., they will not be squeezed or moved.

[0061] In this embodiment of the cementing device, the packer 2 achieves setting by pressurizing the working fluid in the staged cement injector 1. During the setting process, due to the structural improvement in the staged cement injector 1, the setting pressure can be increased in the case of incomplete setting, thereby improving the sealing level of the entire cementing device.

[0062] In another alternative embodiment, refer to Figures 3-7 As shown, the above-mentioned cementing device may further include: a lower connector 28; the lower connector 28 is connected to the central pipe 21 of the packer 2 and abuts against the second wedge ring 27 of the packer 2. In this embodiment, the lower connector 28 is used to connect other pipes or equipment to facilitate the lowering of the cementing device during construction.

[0063] Based on the same inventive concept, this embodiment of the invention also provides a cementing system for staged cementing, which may include: a fluid supply pipeline and the above-mentioned cementing device for staged cementing, wherein the fluid supply pipeline is connected to the upper connector 124 of the staged cementing device 1.

[0064] Based on the same inventive concept, this invention also provides an application of a staged cementing device in a cementing system.

[0065] Based on the same inventive concept, this invention also provides an application of a staged cementing cementing device in a cementing system.

[0066] For a detailed description of the cementing device, cementing system, cementing injector, and cementing apparatus described above in this invention, as well as their beneficial effects, please refer to the relevant introduction of the cementing injector described above. The embodiments of this invention will not be repeated here.

[0067] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. This disclosure is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this disclosure is limited only by the appended claims. Thus, if these modifications and variations of the invention fall within the scope of the claims of the invention and their equivalents, the invention is also intended to include these modifications and variations.

Claims

1. A graded cement injector, characterized in that, include: The system comprises a body, an opening sleeve, an opening ring, a first housing, a second housing, and a piston; the body, the first housing, and the second housing are connected in sequence. The opening sleeve has a first through hole on its wall. An opening ring is embedded inside the opening sleeve, covering the first through hole and connected to the opening sleeve via a first pin. The opening sleeve is embedded inside the body and the first housing, and is connected to the body via a second pin. A fluid channel communicating with the first through hole is formed between the opening sleeve and the first housing, and the fluid channel communicates with a first chamber enclosed by the first housing. The second housing is used to cooperate with the central tube of the packer. A second chamber accommodating the piston is formed between the second housing and the central tube, and the piston is connected to the second housing via a third pin. The first chamber and the second chamber communicate with each other. The opening plug, which is used to cooperate with the opening ring, is pumped into the staged cement injector to pressurize and shear the first pin. The working fluid acts on the piston through the first through hole, the fluid channel, the first chamber and the second chamber and shears the third pin to achieve the setting of the external packer. The main body has a second through hole that connects the inside and outside of the main body; in the first state, the opening sleeve covers the second through hole; in the second state, the second pin is sheared under pressure and the opening sleeve moves so that the working fluid is injected through the second through hole into the annulus between the staged cementing device and the casing to achieve cementing.

2. The graded cement injector according to claim 1, characterized in that, Also includes: An opening end ring is located inside the opening sleeve and at a first preset distance from the opening ring. The opening end ring is connected to the opening sleeve and is used to limit the opening ring.

3. The graded cement injector according to claim 2, characterized in that, Also includes: A closing sleeve and a closing end ring nested inside the closing sleeve; the closing end ring is limited by the opening sleeve and is used to cooperate with the closing plug; At least a portion of the closing sleeve is located between the body and the opening sleeve. The closing sleeve is connected to the body via a fourth pin. A third through hole is provided on the wall of the closing sleeve, which communicates with the second through hole. The closing plug is pumped into the graded cement injector to pressurize and shear the fourth pin, causing the third through hole and the second through hole on the closing sleeve to be misaligned, thereby closing the second through hole.

4. The graded cement injector according to claim 1, characterized in that, Also includes: A housing seat located inside the first housing and at a second preset distance from the opening sleeve, which limits the opening sleeve; The housing base is connected to the first housing, or the housing base is an extension of the first housing.

5. The graded cement injector according to claim 1, characterized in that, The opening ring is provided with a stepped platform, which is used to cooperate with the opening plug.

6. The graded cement injector according to claim 1, characterized in that, The first housing has a fourth through hole communicating with the first chamber, and a check valve is provided in the fourth through hole.

7. The graded cement injector according to any one of claims 1 to 6, characterized in that, Also includes: Upper connector; the upper connector is connected to the body.

8. A cementing device for staged cementing, characterized in that, include: Packer and graded cement injector as described in any one of claims 1 to 7; The central tube of the packer is connected to the second housing in the staged cement injector, and the central tube and the second housing form a second chamber for accommodating the piston in the staged cement injector.

9. The cementing device according to claim 8, characterized in that, The packer includes: a central tube, and an inner wedge ring, a pressure ring, a rubber sleeve, a first wedge ring, a slip, and a second wedge ring sequentially sleeved on the outside of the central tube; a portion of the pressure ring wraps around the outside of the inner wedge ring; the inner wedge ring and the pressure ring abut against the piston.

10. The cementing apparatus according to claim 8 or 9, characterized in that, Also includes: The lower connector is connected to the center tube of the packer and engages with the second wedge ring of the packer.

11. A staged cementing system, characterized in that, include: The fluid supply pipeline and the cementing apparatus for staged cementing as described in any one of claims 8 to 10, wherein the fluid supply pipeline is connected to the upper connector of the staged cementing unit in the cementing apparatus.

12. The application of a staged cementing device as described in any one of claims 1 to 7 in a cementing system.

13. The application of a cementing device for graded cementing as described in any one of claims 8 to 10 in a cementing system.

Images