Single-stage double-plug rubber plug group for well cementation

Abstract

The invention discloses a single-stage double-plug rubber plug set for well cementation, and relates to the technical field of well cementation rubber plugs, the single-stage double-plug rubber plug set for well cementation comprises an upper rubber plug, a connecting block and a first neck bush are arranged in the upper rubber plug, a lower rubber plug is arranged below the upper rubber plug, a second neck bush is arranged in the lower rubber plug, and a fixing ring is fixedly connected to the second neck bush; a mounting block, a rupture disc, a first fixing block and a second fixing block are fixedly connected to the fixing ring, a first rotating plate is rotatably mounted on the first fixing block, and a second rotating plate is rotatably mounted on the second fixing block. The problem that in the continuous downward moving process of an existing lower rubber plug, due to the fact that a rupture disk is pressed and increased, the rupture disk is fractured in advance is solved, and in the process that cement paste pushes the lower rubber plug to move downwards to the bottommost end of a casing pipe, when the lower rubber plug is blocked by foreign matter in the casing pipe, the rupture disk is pressed and increased, the rupture disk is fractured; the first rotating plate and the second rotating plate on the upper side and the lower side of the rupture disc are fixed under the clamping effect of the butt joint block, and then the rupture disc is prevented from being broken in advance.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of cementing plugs, in particular to a single-stage double-plug cementing plug set. BACKGROUND

[0002] The cementing plug is a key tool in the cementing operation of oil drilling, which plays a role in isolation and cleaning in the casing, and is mainly used to isolate different fluids and clean the inner wall of the casing. The cementing plug prevents the leakage of greenhouse gases such as methane during production, provides a foundation for low-carbon oil and gas exploration, and realizes low-carbon exploration. At the same time, the cementing plug ensures the long-term stability of the wellbore, reduces the additional operation and energy consumption caused by well repair or re-drilling, and provides key technical support for the green and low-carbon transformation of oilfields through carbon capture and storage and other technologies.

[0003] The existing cementing plug still has some deficiencies. The patent with publication number CN101979821B discloses a self-locking cementing plug combination device, which includes an upper plug core, a lower plug core, a plug body, a float collar body, a plug seat, a float collar core seat, and a one-way valve. The upper plug core and the lower plug core are fixed together, the plug body is fixed on the upper plug core, there is a retreat groove on the outside of the lower plug core, the float collar core seat includes an upper connecting sleeve and a lower connecting sleeve, the lower end of the upper connecting sleeve is fixed on the upper end of the lower connecting sleeve, the lower part of the lower connecting sleeve is tapered from wide to narrow, and the lower part of the lower connecting sleeve is fixedly installed with the lower part of the float collar body. Through the cooperation of the self-locking device and the lower plug core, self-locking is formed when the replacement slurry ends, preventing the cement slurry from flowing back due to the failure of the float collar seal, which has good use effect, low cost, and reduces safety hazards.

[0004] Although the above-mentioned device can prevent the cement slurry from flowing back, in the current single-stage double-plug cementing process, the core function of the lower plug depends on the one-time rupture disc at the bottom of the lower plug. The rupture disc is always in a state of being pressed to break during the entire downward movement of the lower plug. Therefore, the existing lower plug has the following defects: When the lower plug moves downward and cleans the inner wall of the casing, it may be stuck or blocked halfway due to irregular wellbore, casing foreign matter, or slurry sediment. When the lower plug is stuck, the pressure generated by pumping the cement slurry will continue to act on the rupture disc. Once the pressure of the cement slurry exceeds the pressure limit of the rupture disc, it will cause the rupture disc to break prematurely. The premature rupture of the rupture disc will cause the subsequent cement slurry to mix directly with the preflush through the broken lower plug, resulting in the failure of the cement slurry performance. In the prior art, the rupture disc is triggered by seating the lower plug and the float collar, which increases the pressure on the rupture disc on the lower plug. However, during the continuous downward movement of the lower plug, there is still a risk of rupture of the rupture disc due to increased pressure. Therefore, the prior art lacks a safety protection structure to prevent the rupture disc from being triggered prematurely during the journey. SUMMARY

[0005] The purpose of this invention is to provide a single-stage double-plug rubber plug assembly for cementing, in order to solve the problem that the rupture disc will rupture prematurely due to increased pressure during the continuous downward movement of the existing rubber plug.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a single-stage double-plug rubber plug assembly for cementing, comprising an upper plug, a connecting block and a first inner liner disposed inside the upper plug, a lower plug disposed below the upper plug, a second inner liner disposed inside the lower plug, a fixing ring fixedly connected to the second inner liner, an mounting block, a fracture plate, a first fixing block and a second fixing block fixedly connected to the fixing ring, a first rotating plate rotatably mounted on the first fixing block, and a second rotating plate rotatably mounted on the second fixing block, wherein the first fixing block and the first rotating plate, and the second fixing block and the second rotating plate are connected in a manner that allows for proper connection between them. Protective components are installed between the plates. A first connecting plate, a second connecting plate, and a bracket are fixedly connected to the fixing ring. A first pressure block is slidably installed on the first connecting plate, and a second pressure block is slidably installed on the second connecting plate. A connecting plate is installed on the side of the first pressure block. An extension rod is provided between two adjacent connecting plates. A pressure rod is installed on the first connecting plate, and an adsorption component is installed below the pressure rod. A traction steel rope is fixedly connected to the top of the extension rod. A third guide wheel is rotatably installed on the bracket, and the traction steel rope is guided by the third guide wheel and connected to the second pressure block.

[0007] As a further embodiment of the present invention: the inner wall of the upper rubber plug is in contact with the outer wall of the connecting block, the central axes of the upper rubber plug, the connecting block, the first inner liner, the lower rubber plug and the second inner liner are collinear, and an automatic docking assembly is installed between the connecting block and the first inner liner.

[0008] As a further embodiment of the present invention: the lower rubber plug, the second inner liner, the fixing ring and the mounting block are fixedly connected as an integral structure, the position and number of the mounting blocks correspond one-to-one with the position and number of the first rotating plate and the second rotating plate, and the mounting blocks are made of rubber.

[0009] As a further embodiment of the present invention: the rupture disc includes a rubber disc fixedly connected to a fixing ring and a mounting block, and the rubber disc is provided with a first groove, a second groove and a third groove.

[0010] As a further embodiment of the present invention: the first groove, the second groove, and the third groove are evenly spaced on the upper and lower sides of the rubber disc, the sum of the depths of the first groove and the third groove is equal to the depth of the second groove, and twice the depth of the second groove is less than the thickness of the rubber disc.

[0011] As a further embodiment of the present invention: the first groove, the second groove and the third groove are all in the shape of a cross on the upper and lower sides of the rubber disc, and the inner wall of the third groove is inclined.

[0012] As a further scheme of the present application: the protection assembly comprises a docking groove opened on the first rotating plate, a docking block slidingly installed on the docking groove, a guide block fixedly arranged on the side surface of the first fixed block, a first alloy steel spring installed between the guide block and the docking block, a connecting belt fixedly connected to the docking block, the connecting belt being guided by the first guide wheel and the second guide wheel and connected to the sliding plate, a V-shaped groove opened on the sliding plate, the first guide wheel and the second guide wheel being rotationally connected to the fixed ring, and the sliding plate being slidingly installed on the fixed ring.

[0013] As a further scheme of the present application: the docking block is installed with heat insulation plates on the upper and lower sides, and the connection modes between the protection assembly and the first fixed block and the first rotating plate and between the second fixed block and the second rotating plate are the same.

[0014] As a further scheme of the present application: the adsorption assembly comprises first and second magnetic blocks fixedly connected to the lower rubber plug, a first connecting ring fixedly arranged on the pressure rod, first and second through holes opened on the first connecting ring, a magnetic ring arranged below the first connecting ring, and the magnetic ring, the first magnetic block and the second magnetic block being samarium-cobalt magnets.

[0015] As a further scheme of the present application: the automatic docking assembly comprises a first engaging block fixedly connected below the connecting block, a clamping groove opened on the first engaging block, a second connecting ring fixedly connected to the first inner bushing, a clamping block slidingly installed in the first inner bushing, a second alloy steel spring arranged between the first inner bushing and the clamping block, a second engaging block fixedly arranged on the second connecting ring, and the first engaging block and the second engaging block being inclined on the two sides.

[0016] Compared with the prior art, the present application has the following beneficial effects: 1. The protection assembly is arranged to prevent the rupture disc of the lower rubber plug from being broken in advance. When the displacement fluid pushes the upper rubber plug to move downward, the upper rubber plug pushes the cement slurry in the sleeve to move downward, and the cement slurry pushes the lower rubber plug to move downward to the bottom end of the sleeve. In this process, when the lower rubber plug is blocked by foreign matters in the sleeve, the four sets of first and second rotating plates on the upper and lower sides of the rupture disc are kept fixed under the clamping action of the docking block, thereby avoiding the rupture disc from being broken in advance, ensuring the safety of the device in use, and avoiding the rupture disc from being broken in advance when the lower rubber plug does not move to the specified position, so that the cement slurry is mixed with the preflush fluid, and the safety of the device in use is enhanced.

[0017] 2、The device is provided with an extension rod and an adsorption assembly, so that the device can automatically start the rupture disc after the lower rubber plug moves to the lowermost position, and when the lower rubber plug moves to the bottom of the sleeve, the magnetic ring will adsorb the first magnetic block and the second magnetic block, so as to push the pressure rod upward by using the adsorption force, in the process of upward movement of the pressure rod, the first pressure block pushes the two groups of slides below the device, the extension rod pulls the traction steel rope, the traction steel rope makes the two groups of slides above the second pressure block downward under the guidance of the third guide wheel, so that the adjacent two slides are away from each other, the connecting belt pulls the butt joint block under the guidance of the first guide wheel and the second guide wheel, so that the butt joint block is separated from the butt joint groove, and the first rotating plate and the second rotating plate are both separated from the clamping state, under the action of the cement slurry pressure, the rupture disc breaks along the inclined inner wall of the third groove, and the cement slurry is injected into the annulus, so that the protection function of the rupture disc is realized. Since the first connecting ring used with the first magnetic block and the second magnetic block is porous, the upward pressure of the lower rubber plug during downward pressing can be reduced, the stability of the device during use is ensured, and the stability of the device during use is ensured.

[0018] 3、The device is provided with an automatic butt joint assembly, when the upper rubber plug moves to the upper surface of the lower rubber plug, the first butt joint block and the second butt joint block automatically align and fit under the action of the pressure of the displacement fluid by using the inclined surface structure, and the first butt joint block moves downward and abuts against the clamping block, so that the second alloy steel spring is compressed until the clamping block is completely moved into the clamping groove, so that the function of automatically butt joining the upper rubber plug and the lower rubber plug after the cement slurry is injected into the annulus is realized, and the backflow of the cement slurry is avoided. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 It is a schematic diagram of the overall structure of the present application; Figure 2 It is a schematic diagram of the split structure of the upper rubber plug and the connecting block of the present application; Figure 3 It is Figure 2 It is an enlarged schematic diagram of the structure at A in the middle; Figure 4 It is Figure 2 It is an enlarged schematic diagram of the structure at B in the middle; Figure 5 It is a schematic diagram of the internal structure of the lower rubber plug of the present application; Figure 6 It is Figure 5 It is an enlarged schematic diagram of the structure at C in the middle; Figure 7 It is a schematic diagram of the connection structure of the lower rubber plug and the second inner liner of the present application; Figure 8 It is Figure 7 It is an enlarged schematic diagram of the structure at D in the middle; Figure 9 It is a schematic diagram of the overall split structure of the present application; Figure 10The schematic view of the split structure of the upper rubber plug and the first connecting ring of the application; Figure 11 The schematic view of the connecting structure of the fixed ring and the mounting block of the application.

[0020] Fig. 1: upper rubber plug; 2: connecting block; 3: first inner bushing; 4: lower rubber plug; 5: second inner bushing; 6: fixed ring; 7: mounting block; 8: rupture disc; 801: rubber disc; 802: first groove; 803: second groove; 804: third groove; 9: first fixed block; 10: first rotating plate; 11: second fixed block; 12: second rotating plate; 13: protection assembly; 1301: butt joint groove; 1302: butt joint block; 1303: guide block; 1304: first alloy steel spring; 1305: connecting belt; 1306: first guide wheel; 1307: second guide wheel; 1308: sliding plate; 1309: V-shaped groove; 1310: heat insulation plate; 14: first pressing block; 15: pressing rod; 16: first link plate; 17: connecting plate; 18: extension rod; 19: adsorption assembly; 1901: first magnetic block; 1902: second magnetic block; 1903: first connecting ring; 1904: first through hole; 1905: second through hole; 1906: magnetic ring; 20: second pressing block; 21: second link plate; 22: traction steel rope; 23: third guide wheel; 24: support; 25: automatic butt joint assembly; 2501: first link block; 2502: clamping groove; 2503: second connecting ring; 2504: clamping block; 2505: second alloy steel spring; 2506: second link block. DETAILED DESCRIPTION

[0021] The technical solutions in the embodiments of the application will be described clearly and completely below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the application.

[0022] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second", "third" are only for the purpose of description, and cannot be understood as indicating or implying relative importance. In the description of the present application, it should be noted that unless otherwise specifically specified and limited, the terms "mounting", "connecting", "connecting", "setting" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium, or it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances. The embodiments will be described below according to the overall structure of the present application.

[0023] Embodiment 1: As Figures 1-11As shown, the embodiment proposes a single-stage double plug rubber plug set for cementing, which comprises an upper rubber plug 1, a connecting block 2 and a first inner bushing 3 are arranged in the upper rubber plug 1, a lower rubber plug 4 is arranged below the upper rubber plug 1, a second inner bushing 5 is arranged in the lower rubber plug 4, the first inner bushing 3 and the second inner bushing 5 are used to ensure the strength of the upper rubber plug 1 and the lower rubber plug 4, the connecting block 2 facilitates subsequent butt joint of the upper rubber plug 1 and the lower rubber plug 4, the second inner bushing 5 is fixedly connected with a fixing ring 6, the fixing ring 6 is fixedly connected with a mounting block 7, a rupture disc 8, a first fixing block 9 and a second fixing block 11, the first fixing block 9 is rotatably installed with a first rotating plate 10, the second fixing block 11 is rotatably installed with a second rotating plate 12, the first rotating plate 10 and the second rotating plate 12 are respectively used to protect the upper and lower sides of the rupture disc 8, the first fixing block 9 and the first rotating plate 10 and the second fixing block 11 and the second rotating plate 12 are both installed with a protection assembly 13, the protection assembly 13 can keep the first rotating plate 10 and the second rotating plate 12 locked when the rupture disc 8 is not moved to the bottom of the casing, so as to avoid the rupture disc 8 from being ruptured in advance due to excessive pressure in the moving process, thereby enhancing the safety of the device in use, the fixing ring 6 is fixedly connected with a first abutment plate 16, a second abutment plate 21 and a bracket 24, the first abutment plate 16 is slidably installed with a first pressing block 14, the second abutment plate 21 is slidably installed with a second pressing block 20, the side surface of the first pressing block 14 is installed with a connecting plate 17, the adjacent two connecting plates 17 are provided with an extension rod 18, the first abutment plate 16 is installed with a pressing rod 15, the lower portion of the pressing rod 15 is installed with an adsorption assembly 19, the top of the extension rod 18 is fixedly connected with a traction steel wire 22, the bracket 24 is rotatably installed with a third guide wheel 23, the traction steel wire 22 is connected with the second pressing block 20 through the third guide wheel 23. When the lower rubber plug 4 is moved to the bottom of the casing, the adsorption assembly 19 can act on the pressing rod 15, the connecting plate 17 and the extension rod 18 are driven upward by the pressing rod 15, the first pressing block 14 on the first abutment plate 16 is moved upward, the extension rod 18 pulls the traction steel wire 22, the second pressing block 20 on the second abutment plate 21 is driven downward under the guidance of the third guide wheel 23, and then the protection assembly 13 on the upper and lower sides of the rupture disc 8 is respectively acted on by the first pressing block 14 and the second pressing block 20, so that the protection assembly 13 is no longer engaged with the first rotating plate 10 and the second rotating plate 12, at this time, the first rotating plate 10 and the second rotating plate 12 are automatically rotated under the pressure of the cement slurry and make the rupture disc 8 rupture, so that the lower rubber plug 4 is moved to the appropriate position and then triggers the rupture disc 8 to rupture.

[0024] Example 2: The scheme in Example 1 is further introduced in combination with a specific working mode, and details are described below: As Figures 1-3As shown, in a preferred embodiment, based on the above method, the inner wall of the upper rubber plug 1 is further fitted to the outer wall of the connecting block 2. The central axes of the upper rubber plug 1, the connecting block 2, the first inner sleeve 3, the lower rubber plug 4 and the second inner sleeve 5 are collinear. An automatic docking component 25 is installed between the connecting block 2 and the first inner sleeve 3. The automatic docking component 25 can automatically align with the lower rubber plug 4 after the upper rubber plug 1 moves to the bottom. The first inner sleeve 3 and the connecting block 2 enhance the overall strength of the upper rubber plug 1.

[0025] like Figure 4 As shown, in a preferred embodiment, based on the above method, the lower rubber plug 4, the second inner liner 5, the fixing ring 6 and the mounting block 7 are further fixedly connected as an integral structure. The position and number of the mounting blocks 7 correspond one-to-one with the position and number of the first rotating plate 10 and the second rotating plate 12. The mounting blocks 7 are made of rubber. When each set of the first rotating plate 10 and the second rotating plate 12 rotates, the rubber mounting blocks 7 will be squeezed and deformed, thereby ensuring that the cement slurry can flow downward.

[0026] like Figure 2 and Figure 4 As shown, in a preferred embodiment, based on the above method, the rupture disc 8 further includes a rubber disc 801 fixedly connected to the fixing ring 6 and the mounting block 7. The rubber disc 801 has a first groove 802, a second groove 803 and a third groove 804. The first groove 802, the second groove 803 and the third groove 804 extend to the periphery of the rubber disc 801 to form an easy-tear line, so that it will automatically rupture when subjected to excessive pressure.

[0027] like Figure 4 As shown, in a preferred embodiment, based on the above method, the first groove 802, the second groove 803, and the third groove 804 are evenly distributed on the upper and lower sides of the rubber disc 801. The sum of the depths of the first groove 802 and the third groove 804 is equal to the depth of the second groove 803. Twice the depth of the second groove 803 is less than the thickness of the rubber disc 801, ensuring the overall sealing of the rubber disc 801. At the same time, the two sets of grooves symmetrically distributed on the upper and lower sides are convenient for subsequent use as easy-tear lines. After the rubber disc 801 is broken, the cement slurry can flow downwards.

[0028] like Figure 4 As shown, in a preferred embodiment, based on the above method, the first groove 802, the second groove 803 and the third groove 804 are all in the shape of a cross on the upper and lower sides of the rubber disc 801, which facilitates the rapid injection of cement slurry. The inner wall of the third groove 804 is inclined. The inclined structure of the third groove 804 makes the rubber disc 801 more prone to breakage when it is not supported, thus enhancing the stability during use.

[0029] likeFigures 2-8 As shown in the preferred embodiment, on the basis of the above-mentioned mode, further, the protection assembly 13 comprises a docking groove 1301 opened on the first rotating plate 10, a docking block 1302 is slidingly installed on the docking groove 1301, a guide block 1303 is fixedly arranged on the side of the first fixed block 9, a first alloy steel spring 1304 is installed between the guide block 1303 and the docking block 1302, a connecting belt 1305 is fixedly connected on the docking block 1302, the connecting belt 1305 is guided by the first guide wheel 1306 and the second guide wheel 1307 and connected with the sliding plate 1308, the V-shaped groove 1309 is opened on the sliding plate 1308, the first guide wheel 1306 and the second guide wheel 1307 are rotatably connected with the fixed ring 6, and the sliding plate 1308 is slidingly installed on the fixed ring 6. When the adjacent two sliding plates 1308 are close to each other, as shown in Figure 8 As shown in the preferred embodiment, on the basis of the above-mentioned mode, further, the protection assembly 13 comprises a docking groove 1301 opened on the first rotating plate 10, a docking block 1302 is slidingly installed on the docking groove 1301, a guide block 1303 is fixedly arranged on the side of the first fixed block 9, a first alloy steel spring 1304 is installed between the guide block 1303 and the docking block 1302, a connecting belt 1305 is fixedly connected on the docking block 1302, the connecting belt 1305 is guided by the first guide wheel 1306 and the second guide wheel 1307 and connected with the sliding plate 1308, the V-shaped groove 1309 is opened on the sliding plate 1308, the first guide wheel 1306 and the second guide wheel 1307 are rotatably connected with the fixed ring 6, and the sliding plate 1308 is slidingly installed on the fixed ring 6. When the adjacent two sliding plates 1308 are close to each other, as shown in

[0030] As shown in the preferred embodiment, on the basis of the above-mentioned mode, further, the protection assembly 13 comprises a docking groove 1301 opened on the first rotating plate 10, a docking block 1302 is slidingly installed on the docking groove 1301, a guide block 1303 is fixedly arranged on the side of the first fixed block 9, a first alloy steel spring 1304 is installed between the guide block 1303 and the docking block 1302, a connecting belt 1305 is fixedly connected on the docking block 1302, the connecting belt 1305 is guided by the first guide wheel 1306 and the second guide wheel 1307 and connected with the sliding plate 1308, the V-shaped groove 1309 is opened on the sliding plate 1308, the first guide wheel 1306 and the second guide wheel 1307 are rotatably connected with the fixed ring 6, and the sliding plate 1308 is slidingly installed on the fixed ring 6. When the adjacent two sliding plates 1308 are close to each other, as shown in Figure 4 Figure 8 As shown in the preferred embodiment, on the basis of the above-mentioned mode, further, the protection assembly 13 comprises a docking groove 1301 opened on the first rotating plate 10, a docking block 1302 is slidingly installed on the docking groove 1301, a guide block 1303 is fixedly arranged on the side of the first fixed block 9, a first alloy steel spring 1304 is installed between the guide block 1303 and the docking block 1302, a connecting belt 1305 is fixedly connected on the docking block 1302, the connecting belt 1305 is guided by the first guide wheel 1306 and the second guide wheel 1307 and connected with the sliding plate 1308, the V-shaped groove 1309 is opened on the sliding plate 1308, the first guide wheel 1306 and the second guide wheel 1307 are rotatably connected with the fixed ring 6, and the sliding plate 1308 is slidingly installed on the fixed ring 6. When the adjacent two sliding plates 1308 are close to each other, as shown in

[0031] As shown in the preferred embodiment, on the basis of the above-mentioned mode, further, the protection assembly 13 comprises a docking groove 1301 opened on the first rotating plate 10, a docking block 1302 is slidingly installed on the docking groove 1301, a guide block 1303 is fixedly arranged on the side of the first fixed block 9, a first alloy steel spring 1304 is installed between the guide block 1303 and the docking block 1302, a connecting belt 1305 is fixedly connected on the docking block 1302, the connecting belt 1305 is guided by the first guide wheel 1306 and the second guide wheel 1307 and connected with the sliding plate 1308, the V-shaped groove 1309 is opened on the sliding plate 1308, the first guide wheel 1306 and the second guide wheel 1307 are rotatably connected with the fixed ring 6, and the sliding plate 1308 is slidingly installed on the fixed ring 6. When the adjacent two sliding plates 1308 are close to each other, as shown in Figure 1 Figure 2 Figure 5 Figure 6 ​​​​As shown, in a preferred embodiment, based on the above method, the adsorption assembly 19 further includes a first magnetic block 1901 and a second magnetic block 1902 fixedly connected to the lower rubber plug 4. A first connecting ring 1903 is fixedly disposed on the pressure rod 15. The first connecting ring 1903 has a first through hole 1904 and a second through hole 1905. A magnetic ring 1906 is disposed below the first connecting ring 1903. The magnetic ring 1906, the first magnetic block 1901 and the second magnetic block 1902 are all samarium cobalt magnets. The magnetic ring 1906 is used to connect with the sleeve. When the lower rubber plug 4 moves to the bottom of the sleeve, the first magnetic block 1901 and the second magnetic block 1902 on the lower rubber plug 4 are attracted to the magnetic ring 1906, so that the upper and lower sides of the rubber disc 801 are not obstructed, thus enhancing the safety of the device during use.

[0032] like Figures 1-3 As shown, in a preferred embodiment, based on the above method, the automatic docking assembly 25 further includes a first connecting block 2501 fixedly connected to the lower part of the connecting block 2. The first connecting block 2501 has a slot 2502. A second connecting ring 2503 is fixedly connected to the first inner sleeve 3. A locking block 2504 is slidably installed inside the first inner sleeve 3. A second alloy steel spring 2505 is provided between the first inner sleeve 3 and the locking block 2504. A second connecting block 2506 is fixedly provided on the second connecting ring 2503. Both sides of the first connecting block 2501 and the second connecting block 2506 are inclined. When the upper rubber plug 1 and the connecting block 2 move down to the appropriate position, the inclined surfaces of the first connecting block 2501 and the second connecting block 2506 come into contact with each other. Under the pressure of the displacement liquid, the first connecting block 2501 can press down the locking block 2504. After the inclined surface of the locking block 2504 is pressed, it will retract into the first inner liner 3, and the second alloy steel spring 2505 will be compressed until the locking block 2504 moves into the locking groove 2502, completing the docking of the upper and lower rubber plugs.

[0033] Example 3: The solutions in Embodiments 1 and 2 will be further described below with reference to their specific working methods. Specifically, when using this cementing single-stage double-plug rubber plug assembly: ... Figures 1-5 and Figures 9-11As shown, the first inner sleeve 3 and the second inner sleeve 5 are used to improve the strength of the upper rubber plug 1 and the lower rubber plug 4, and the automatic butt joint assembly 25 on the connecting block 2 facilitates the subsequent butt joint of the upper rubber plug 1 and the lower rubber plug 4, thereby avoiding the backflow of the cement slurry. The first rotating plate 10 and the second rotating plate 12 cooperate with the protection assembly 13 to support and protect the upper and lower sides of the rupture disc 8, thereby avoiding the rupture of the rupture disc 8 before it moves to the designated position. When the rupture disc 8 does not move to the bottom of the casing, the protection assembly 13 no longer protects the upper and lower sides of the rupture disc 8 under the action of the adsorption assembly 19, so that the protection of the rupture disc 8 is provided during its downward movement and activated after it touches the bottom. The first rotating plate 10 and the second rotating plate 12 are changed from the locked state to the rotatable state, so that the rupture disc 8 is automatically ruptured under the action of the cement slurry pressure. At this time, the upper rubber plug 1 can be pushed downward by the displacement fluid until the cement slurry is injected into the annulus. The specific steps are as follows, as shown in Figure 1 、 Figure 2 、 Figure 5 and Figure 6 As shown, the magnetic ring 1906 is used to be installed at the bottom of the casing. When the lower rubber plug 4 moves to the bottom of the casing, the first magnetic block 1901 and the second magnetic block 1902 on the lower rubber plug 4 are adsorbed by the magnetic ring 1906. At this time, the magnetic ring 1906 indirectly pushes the first pressing block 14, the pressing rod 15, the first connecting plate 16, the connecting plate 17 and the extension rod 18 to move upward. When the extension rod 18 moves upward, it will slide in the second connecting ring 2503, as shown in Figure 8 The extension rod 18 will also pull the traction steel rope 22, so that the traction steel rope 22 drives the second pressing block 20 on the second connecting plate 21 to move downward under the guidance of the third guide wheel 23. Then, the first pressing block 14 and the second pressing block 20 act on the protection assembly 13 on the upper and lower sides of the rupture disc 8, respectively, so that the protection assembly 13 is no longer engaged with the first rotating plate 10 and the second rotating plate 12. At this time, the first rotating plate 10 and the second rotating plate 12 are automatically rotated under the action of the cement slurry pressure and make the rupture disc 8 rupture. The lower rubber plug 4 moves to the appropriate position before the rupture disc 8 is ruptured. The first through hole 1904 and the second through hole 1905 on the first connecting ring 1903 are used to butt joint with the first magnetic block 1901 and the second magnetic block 1902, thereby ensuring the sealing effect of the whole device. At the same time, the hollow structure of the first connecting ring 1903 can be used to reduce the resistance of the first connecting ring 1903 when the lower rubber plug 4 moves downward, thereby further ensuring the safety of the device during use.

[0034] As shown in Figures 5-8 The specific steps of disengaging the first rotating plate 10 and the second rotating plate 12 are as follows. The second pressing block 20 moves downward and pushes the adjacent two sliding plates 1308 on the upper layer of the rupture disc 8. The first pressing block 14 moves upward and pushes the inner wall of the V-shaped groove 1309 on the adjacent two sliding plates 1308 on the lower layer of the device, so that the adjacent two sliding plates 1308 on the upper and lower sides of the rupture disc 8 are close to each other, as shown in Figure 8As shown, the sliding plate 1308 pulls the connecting belt 1305 when moving, the connecting belt 1305 is pulled under the guidance of the first guide wheel 1306 and the second guide wheel 1307, thereby driving the abutting block 1302 to slide in the abutting groove 1301, the first alloy steel spring 1304 on the guide block 1303 is compressed until the abutting block 1302 completely separates from the first rotating plate 10, at this time, the first rotating plate 10 is out of the clamping state and can rotate on the first fixed block 9 under the action of the cement slurry pressure, since the connection mode between the protection assembly 13 and the first fixed block 9 and the first rotating plate 10 and the connection mode between the second fixed block 11 and the second rotating plate 12 are the same, therefore, the second rotating plate 12 can also rotate on the second fixed block 11, at this time, the upper and lower sides of the rubber disc 801 are not blocked and no longer supported and protected, the first groove 802, the second groove 803 and the third groove 804 on the rubber disc 801 can be used as a tear line, the pressure of the cement slurry can make the rubber disc 801 break through the inclined inner wall of the third groove 804, and the breaking track extends along the first groove 802, the second groove 803 and the third groove 804 to the periphery of the breaking disc 8, forming a cross track, so as to inject the cement slurry into the annulus. When the upper rubber plug 1 moves to the lowermost position, the inclined surfaces of the first abutting block 2501 and the second abutting block 2506 contact each other, under the pressure of the top displacement fluid above the upper rubber plug 1, the first abutting block 2501 presses down the clamping block 2504, the inclined surface of the clamping block 2504 is retracted into the first inner liner 3 after being pressed, the second alloy steel spring 2505 is compressed, until the clamping block 2504 moves to the corresponding position of the clamping groove 2502, under the elastic force of the second alloy steel spring 2505, the second abutting block 2506 and the first abutting block 2501 are clamped with each other, completing the abutting work of the upper and lower rubber plugs.

[0035] The above merely describes the preferred embodiments of the present application, but the protection scope of the present application is not limited to this, any person skilled in the art can make equivalent replacement or change according to the technical scheme and the inventive concept of the present application within the technical range disclosed by the present application, which should be covered in the protection scope of the present application.

Claims

1. A single-stage double plug pack for cementing, comprising an upper plug (1), characterized in that, The upper glue plug (1) is provided with a connecting block (2) and a first inner bushing (3), the lower part of the upper glue plug (1) is provided with a lower glue plug (4), the lower glue plug (4) is provided with a second inner bushing (5), the second inner bushing (5) is fixedly connected with a fixed ring (6), the fixed ring (6) is fixedly connected with a mounting block (7), a rupture disc (8), a first fixed block (9) and a second fixed block (11), the first fixed block (9) is rotatably connected with a first rotating plate (10), the second fixed block (11) is rotatably connected with a second rotating plate (12), the first fixed block (9) and the first rotating plate (10) and the second fixed block (11) and the second rotating plate (12) are both provided with a protection assembly (13), the fixed ring (6) is fixedly connected with a first connecting plate (16), a second connecting plate (21) and a support (24), the first connecting plate (16) is slidably connected with a first pressing block (14), the second connecting plate (21) is slidably connected with a second pressing block (20), the side of the first pressing block (14) is provided with a connecting plate (17), the adjacent two connecting plates (17) are provided with an extension rod (18), the first connecting plate (16) is provided with a pressing rod (15), the lower part of the pressing rod (15) is provided with a suction assembly (19), the top of the extension rod (18) is fixedly connected with a traction steel rope (22), the support (24) is rotatably connected with a third guide wheel (23), the traction steel rope (22) is guided by the third guide wheel (23) and connected with the second pressing block (20).

2. A single-stage double plug packer assembly for use in well cementing according to claim 1, characterized in that, The inner wall of the upper glue plug (1) and the outer wall of the connecting block (2) are mutually attached, the central axes of the upper glue plug (1), the connecting block (2), the first inner bushing (3), the lower glue plug (4) and the second inner bushing (5) are collinear, and the connecting block (2) and the first inner bushing (3) are provided with an automatic butt joint assembly (25).

3. A single-stage double plug packer assembly for use in well cementing according to claim 1, characterized in that, The lower glue plug (4), the second inner bushing (5), the fixed ring (6) and the mounting block (7) are fixedly connected as a whole structure, the positions and quantities of the mounting block (7) one-to-one correspond to the positions and quantities of the first rotating plate (10) and the second rotating plate (12), and the material of the mounting block (7) is rubber material.

4. A single-stage double plug packer assembly for use in well cementing according to claim 1, characterized in that, The rupture disc (8) comprises a rubber disc (801) fixedly connected to the fixed ring (6) and the mounting block (7), and the rubber disc (801) is provided with a first groove (802), a second groove (803) and a third groove (804).

5. A single-stage dual plug pack for cementing a well according to claim 4, characterized in that, The first groove (802), the second groove (803) and the third groove (804) are equally spaced on the upper and lower sides of the rubber disc (801), the sum of the depths of the first groove (802) and the third groove (804) is equal to the depth of the second groove (803), and twice the depth of the second groove (803) is less than the thickness of the rubber disc (801).

6. A single-stage dual plug pack for cementing a well according to claim 5, characterized in that, The first groove (802), the second groove (803) and the third groove (804) are both "cross" shaped on the upper and lower sides of the rubber disc (801), and the inner wall of the third groove (804) is inclined.

7. A single-stage dual plug pack for cementing a well according to claim 1, characterized in that, The protection assembly (13) comprises a butt joint groove (1301) formed on the first rotating plate (10), a butt joint block (1302) slidably mounted on the butt joint groove (1301), a guide block (1303) fixedly arranged on the side of the first fixed block (9), a first alloy steel spring (1304) mounted between the guide block (1303) and the butt joint block (1302), a connecting belt (1305) fixedly connected to the butt joint block (1302), the connecting belt (1305) connected to a sliding plate (1308) through first and second guide wheels (1306, 1307), a V-shaped groove (1309) formed on the sliding plate (1308), and the first and second guide wheels (1306, 1307) rotatably connected to the fixed ring (6), wherein the sliding plate (1308) is slidably mounted on the fixed ring (6).

8. A single-stage double plug packer assembly for use in well cementing according to claim 7, characterized in that, The butt joint block (1302) is provided with heat insulation plates (1310) on the upper and lower sides thereof, and the protection assembly (13) is connected to the first fixed block (9) and the first rotating plate (10) in the same way as the second fixed block (11) and the second rotating plate (12).

9. A single-stage dual plug pack for cementing a well according to claim 1, characterized in that, The adsorption assembly (19) comprises first and second magnetic blocks (1901, 1902) fixedly connected to the lower rubber plug (4), a first connecting ring (1903) fixedly arranged on the pressing rod (15), first and second through holes (1904, 1905) formed in the first connecting ring (1903), a magnetic ring (1906) arranged below the first connecting ring (1903), and the magnetic ring (1906), the first magnetic block (1901) and the second magnetic block (1902) are samarium-cobalt magnets.

10. A single stage double plug packer assembly for use in well cementing according to claim 2, wherein, The automatic butt joint assembly (25) comprises a first link block (2501) fixedly connected to the lower side of the connecting block (2), a clamping groove (2502) formed in the first link block (2501), a second connecting ring (2503) fixedly connected to the first inner bushing (3), a clamping block (2504) slidably mounted in the first inner bushing (3), a second alloy steel spring (2505) arranged between the first inner bushing (3) and the clamping block (2504), a second link block (2506) fixedly arranged on the second connecting ring (2503), and the first link block (2501) and the second link block (2506) are both inclined.

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