A traversable composite rubber plug for cementing and use method thereof

Abstract

The present invention discloses a traversable composite rubber plug for cementing and a method of using the same, comprising an annulus rubber plug and an inner rubber plug, wherein the lower portion of the inner wall of the annulus is provided with an inwardly protruding blocking portion which can move outward; the outer wall of the inner rubber plug is provided with wings, and the bottom of the outer wall is provided with an outwardly protruding clamping portion; the inner rubber plug can enter the inner cavity of the annulus rubber plug from the upper portion of the annulus rubber plug and be clamped on the blocking portion of the annulus rubber plug; after the blocking portion moves outward and the blocking is released, the inner rubber plug escapes from the inner cavity of the annulus rubber plug and traverses the annulus rubber plug. The composite rubber plug is characterized in that the inner rubber plug can scrape the cement slurry on the inner wall of the oil pipe; secondly, the inner rubber plug and the annulus rubber plug form a composite rubber plug which can scrape the cement slurry on the casing wall; thirdly, after the composite rubber plug falls and encounters a blocking sleeve, the inner rubber plug jumps out of the annulus rubber plug and scrapes the cement slurry on the inner wall of the oil pipe again, and can also realize a special pressure holding function in combination with an appropriate structure.

Description

Technical Field

[0001] The invention belongs to the technical field of drilling and completion equipment in oil field exploitation, and in particular relates to a cementing composite rubber plug capable of achieving penetration. Background Art

[0002] In the field of drilling and completion technology in oil fields, cementing plugs are often used. Their function is to put in cementing plugs at the final stage of the cementing process and use them to scrape the cement on the well wall to ensure the cleanliness of the wellbore. When the inner diameter of the wellbore is the same, a suitable plug can be used to scrape the well wall. However, when the wellbore or cementing pipe string changes diameter, the corresponding composite plug must be used to scrape the well wall. However, the application of composite plugs is not smooth on site, and there are many problems, such as the cement slurry on the well wall of a small inner diameter wellbore can be scraped clean, but the large inner diameter wellbore cannot be scraped clean, or the composite plug is stuck at the diameter change.

[0003] In the prior art, CN201420681345.3, "Well Cementing Composite Rubber Plug", discloses a composite rubber plug including a first rubber plug, a composite rubber plug short circuit, the composite rubber plug short circuit includes a second rubber plug, the first rubber plug and the second rubber plug are plugged and matched, and can be self-locking; the self-locking impact seat is located at the other end of the composite rubber plug short circuit, and the composite rubber plug and the self-locking impact seat can achieve self-locking. Its function is to use multiple composite rubber plugs in series, which relatively reduces the wear of a single rubber plug and the cement slurry isolation problem, and ensures the construction quality.

[0004] Application No. CN201520575560.X, "A Drill-free Grading Cementing Device with Composite Rubber Plug", discloses a drill-free graded cementing device with a composite rubber plug, which has a hollow rubber plug at the lower end of the plug seat, and the hollow rubber plug is fixed to the inner wall of the lower joint by a shear pin. When in use, after the first-stage cementing is completed, a flexible rubber plug is inserted to descend to the hollow rubber plug and compound with it, the pressure is increased to shear off the shear pin, and the composite rubber plug descends to the bottom of the well to complete the collision and pressure. It overcomes the shortcomings of the existing drill-free graded cementing device that cannot effectively scrape the residual cement slurry on the inner wall of the casing, and the low success rate of the rubber plug and the rubber plug seat falling to the bottom of the well.

[0005] However, the above existing technologies cannot achieve the function of scraping the wall of a variable diameter wellbore at one time. Summary of the invention

[0006] The present invention provides a penetrable composite rubber plug for cementing and a use method thereof, which solves at least one of the above-mentioned technical problems.

[0007] The present invention provides a method that can realize the function of scraping cement on the wall of a well with a small inner diameter by an inner rubber plug, and then when the inner rubber plug reaches the annular rubber plug (i.e., the diameter change point), it forms a composite rubber plug with it, and continues to go down to scrape cement on the wall of a well with a large inner diameter. Furthermore, it also includes that later, when the combined rubber plug reaches the stopper sleeve, the composite rubber plug can be separated, that is, the inner rubber plug can pass through the annular rubber plug, further realizing the function of scraping cement on the wall of a well with a small inner diameter, and at the same time, the setting of the inner rubber plug guide head can be matched with relevant tools to complete the sealing function, further expanding the application scope of the invention.

[0008] In order to achieve the above technical objectives, the present invention adopts the following technical solutions.

[0009] In one aspect, the present invention provides a composite rubber plug for cementing, comprising an annulus rubber plug and an inner rubber plug.

[0010] The annular rubber plug is a rubber plug with a hollow interior, a wing is provided on its outer wall, a cavity is provided inside, and a blocking portion protruding inward is provided at the lower part of its inner wall, and the blocking portion can move outward;

[0011] The outer wall of the inner rubber plug is provided with wings, and the bottom of the outer wall is provided with a clamping portion protruding outwards;

[0012] The outer diameter of the inner rubber plug is not greater than the inner diameter of the annular rubber plug, so that the inner rubber plug can enter the cavity of the ring control rubber plug from the upper part of the annular rubber plug, and the outwardly protruding clamping portion of the inner rubber plug can be clamped on the blocking portion of the annular rubber plug;

[0013] When the blocking portion of the annular rubber plug moves outward and the blocking is released, the inner rubber plug escapes from the inner cavity of the annular rubber plug and passes through the annular rubber plug.

[0014] Furthermore, the traversable composite rubber plug for cementing of the present invention comprises an annulus rubber plug including an upper vulcanized ring, annular rubber, a lower vulcanized ring, a ball locking sleeve, a ball blocking sleeve and a steel ball.

[0015] The outer wall of the ring glue is provided with a plurality of wings from top to bottom, and the upper and lower parts of the ring glue are respectively vulcanized and fixedly connected with the lower part of the upper vulcanization ring and the upper part of the lower vulcanization ring;

[0016] The lower end of the lower vulcanized ring is connected to the ball locking sleeve, the outer wall of the ball locking sleeve is provided with a shoulder, the upper part of the ball blocking sleeve is suspended on the shoulder of the ball locking sleeve, and can move upward along the ball locking sleeve;

[0017] The lower end of the ball lock sleeve is evenly provided with a plurality of ball holes in the circumference, and steel balls are arranged in the ball holes;

[0018] The inner diameter of the upper part of the ball blocking sleeve is equal to the outer diameter of the ball locking sleeve, and the lower part of the inner wall of the ball blocking sleeve is provided with an expanded hole extending outward, and the inner diameter thereof is larger than the outer diameter of the ball locking sleeve;

[0019] When the ball stopper is suspended on the shoulder of the ball stopper, its upper inner wall restricts the movement of the steel ball, causing it to protrude inward to form a blocking portion. When the ball stopper moves upward, the lower expansion hole position moves up to the steel ball position, and the steel ball can move freely outward to release the blockage.

[0020] Furthermore, the traversable composite rubber plug for cementing of the present invention is characterized in that: the inner rubber plug comprises an inner rubber, a vulcanized rod, an inner rubber plug O-ring, and a guide head;

[0021] A plurality of wings are arranged on the outer wall of the inner rubber from top to bottom, the lower part of the inner rubber is fixedly connected to the vulcanization rod by vulcanization, the lower part of the vulcanization rod is threadedly connected to the upper part of the guide head, a shoulder is arranged on the upper part of the guide head to form the clamping part, and the inner rubber plug is clamped in the inner cavity of the annular rubber plug through the contact between the shoulder on the upper part of the guide head and the steel ball.

[0022] Furthermore, in the traversable composite rubber plug for cementing of the present invention, the receiving tube located in the middle of the cementing device can be sealed by the inner rubber plug O-ring and the guide head.

[0023] Furthermore, in the penetrable composite rubber plug for cementing of the present invention, the inner diameter of the ball stopper sleeve of the annulus rubber plug is larger than the inner diameter of the stopper sleeve in the cementing device, thereby blocking the annulus rubber plug and allowing the ball stopper sleeve to move upward along the locking ball sleeve, and the lower expansion hole position moves up to the steel ball position, and the steel ball can move freely outward to release the obstruction to the inner rubber plug.

[0024] Furthermore, in the traversable composite rubber plug for cementing of the present invention, the annular rubber plug and the inner rubber plug are transitionally matched.

[0025] Furthermore, in the traversable composite rubber plug for cementing of the present invention, the upper portion of the outer wall of the hollow rubber plug is suspended in the inner cavity of the hanger through a connecting piece via copper shear nails.

[0026] On the other hand, the present invention also provides a method for using the above-mentioned penetrable composite rubber plug for cementing, including: an inner rubber plug scraping cement slurry on the wall of the oil pipe; the inner rubber plug enters the annulus rubber plug, and the clamping part of the inner rubber plug is clamped on the blocking part of the annulus rubber plug to form a composite rubber plug, scraping the cement slurry on the inner wall of the completion casing.

[0027] Furthermore, the method for using the penetrable composite rubber plug for cementing of the present invention also includes the steps of moving the blocking portion of the annulus rubber plug outward, releasing the blocking portion, allowing the inner rubber plug to escape from the inner cavity of the annulus rubber plug, penetrating the annulus rubber plug, and continuing to scrape cement slurry on the inner wall of the tool during the descending process. When reaching the receiving tube, it descends with the receiving tube, releases the locking block, and closes the closing sleeve of the cement injector.

[0028] Furthermore, the method for using the traversable composite rubber plug for cementing of the present invention comprises:

[0029] S1 fixes the annular plug in the cavity of the hanger by means of copper shear nails;

[0030] When the designed amount of cement slurry is injected into the S2 string, the inner rubber plug is put into the wellhead. The inner rubber plug goes down with the displacement fluid and scrapes the cement slurry on the wall of the oil pipe.

[0031] S3 When the inner rubber plug descends to the inner cavity of the hanger, the inner rubber plug is blocked by the blocking part at the bottom of the annular rubber plug, and the inner rubber plug and the annular rubber plug form a composite rubber plug;

[0032] As the pressure in the S4 tubing increases, the copper shear pins of the annulus plug are cut off, and the composite plug flows downward with the fluid, and the annulus plug scrapes the cement slurry on the inner wall of the completion casing;

[0033] When the S5 composite rubber plug descends to the cementing device, the preset stopper sleeve in the cementing device contacts the annular rubber plug, and at the same time, the blocking part of the annular rubber plug moves outward, contacts the blocking part, and the inner rubber plug passes through the inner hollow of the annular rubber plug;

[0034] The S6 inner rubber plug continues to scrape the cement slurry on the inner wall of the tool during the downward process;

[0035] When the S7 inner rubber plug continues to move downward to the receiving tube, its lower end and the inner hole of the receiving tube are sealed, the pressure in the casing continues to increase, and the inner rubber plug and the receiving tube cut off the second copper shear nail under the action of the liquid pressure and move downward. At the same time, the locking block is released, the closing sleeve of the cementing device is closed, and the cement slurry is blocked outside the cementing hole to complete the cementing process.

[0036] Furthermore, in the method for using the penetrable composite plug for cementing of the present invention, in S5, the preset stop sleeve in the cementing device contacts the lower part of the ball stop sleeve of the annulus plug, the ball stop sleeve moves upward, the hole expander moves to the steel ball and releases the steel ball, thereby removing the obstruction to the inner plug.

[0037] The present invention adopts the above scheme to achieve the following technical effects.

[0038] The penetrable composite rubber plug for cementing and the use method thereof can realize the penetration of the inner rubber plug to the annular rubber plug, and can realize the one-time wall scraping function of the variable diameter wellbore.

[0039] The penetrable composite rubber plug for cementing of the present invention and the use method thereof have three functions. First, the inner rubber plug can realize the function of scraping the cement slurry on the inner wall of the oil pipe (or drill pipe); second, when the inner rubber plug reaches the inner cavity of the annulus rubber plug, it is combined with the annulus rubber plug to form a composite rubber plug, which can realize the function of scraping the cement slurry on the casing wall; third, when the composite rubber plug encounters a stopper sleeve during the falling process, the inner rubber plug can pass through the inner cavity of the annulus rubber plug and realize the function of scraping the cement slurry on the inner wall of the oil pipe (or drill pipe) again, and at the same time, it can cooperate with the structure of the prior art to realize the pressure holding function. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the technical solution of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0041] Figure 1 A schematic diagram of the structure of a composite rubber plug for cementing that can be penetrated, which is composed of an inner rubber plug and an annulus rubber plug;

[0042] Figure 2 It is a schematic diagram of the structure of the penetrable composite rubber plug for cementing of the present invention inside the hanger;

[0043] Figure 3 It is a schematic diagram of the pipe column structure in an embodiment of the present invention;

[0044] Figure 4 It is a schematic structural diagram of the retaining sleeve and the receiving tube in the cementing device of the present invention.

[0045] In the figure: 1-inner rubber plug; 2-upper joint of hanger; 3-connecting piece; 4-copper shear nail; 5-annulus rubber plug; 6-lower joint of hanger; 7-inner rubber; 8-vulcanized rod; 9-inner rubber plug O-ring; 10-guide head; 11-upper vulcanized ring; 12-ring rubber; 13-lower vulcanized ring; 14-locking ball sleeve; 15-blocking ball sleeve; 16-steel ball; 17-upper joint of cementing device; 18-blocking sleeve; 19-closing sleeve; 20-locking block; 21-second copper shear nail; 22-receiving tube; 23-cementing hole; 24-lower joint of cementing device; 25-oil pipe; 26-hanger; 27-completion casing; 28-cementing device; 29-casing wellbore; 30-open hole wellbore.

[0046] It should be understood that the above drawings are only schematic and are not drawn to scale. DETAILED DESCRIPTION

[0047] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0048] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0049] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0050] In the description of the embodiments of the present invention, it should be noted that the terms “first”, “second”, etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0051] See also Figures 1 to 4 The present invention provides a penetrable composite rubber plug for cementing and a method for using the same.

[0052] See also Figure 1 , Figure 2 and Figure 3 , is a penetrable composite rubber plug for cementing of the present invention, which includes an annulus rubber plug 5, and the annulus rubber plug 5 is destructibly suspended in the inner cavity of the hanger 26. Specifically, the upper part of the outer wall of the annulus rubber plug 5 is suspended in the inner cavity of the hanger 26 through a copper shear nail 4 through a connector 3.

[0053] Specifically, the annular rubber plug 5 is a rubber plug with a hollow interior, with wings provided on its outer wall, a cylindrical inner cavity provided inside, and a blocking portion protruding inwardly provided on the lower part of its inner wall, and the blocking portion can move outwardly.

[0054] Specifically, the inner rubber plug 1 has wings on its outer wall and a clamping portion protruding outwards is provided on the bottom of the outer wall.

[0055] The outer diameter of the inner rubber plug 1 is not greater than the inner diameter of the annular rubber plug 5, so that the inner rubber plug 1 can enter the inner hollow of the annular rubber plug 5 from the upper part of the annular rubber plug 5, and the outwardly protruding clamping portion of the inner rubber plug 1 can be clamped on the blocking portion of the annular rubber plug 5, and when the blocking portion of the annular rubber plug 5 moves outward and releases the blocking, the inner rubber plug 1 escapes from the inside of the annular rubber plug 5 and passes through the annular rubber plug 5. It can be seen that the outer diameter of the inner rubber plug 1 is greater than the distance between the blocking portions.

[0056] For more details, see Figure 1 The annular rubber plug 5 is composed of the following parts: an upper vulcanized ring 11, an annular rubber 12, a lower vulcanized ring 13, a ball locking sleeve 14, a ball blocking sleeve 15, and a steel ball 16.

[0057] The outer wall of the ring glue 12 is provided with a plurality of wings from top to bottom to realize the cement slurry scraping function of the casing wall. The upper and lower parts of the ring glue 12 are respectively fixedly connected with the lower part of the upper vulcanization ring 11 and the upper part of the lower vulcanization ring 13 by vulcanization.

[0058] The ball locking sleeve 14 and the ball blocking sleeve 15 are also included. The lower end of the lower vulcanized ring 13 is connected to the ball locking sleeve 14. Specifically, the lower end of the lower vulcanized ring 13 is threadedly connected to the ball locking sleeve 14 through a thread. The outer wall of the ball locking sleeve 14 is provided with a shoulder. The upper part of the ball blocking sleeve 15 is suspended on the shoulder of the ball locking sleeve 14 and can move upward along the ball locking sleeve 14.

[0059] The lower end of the ball lock sleeve 14 is evenly provided with a plurality of ball eyes, for example, six ball eyes, and the cross-sectional shape of the ball eyes is an eight-shaped shape that is narrow inside and wide outside, and a steel ball 16 is arranged inside the ball lock sleeve 15. The inner diameter of the upper part of the ball lock sleeve 15 is equivalent to the outer diameter of the ball lock sleeve 14, and the lower part of the inner wall of the ball lock sleeve 15 is provided with an outwardly extending expansion hole, and the inner diameter is larger than the outer diameter of the ball lock sleeve 14. When the ball lock sleeve 15 is normally suspended on the shoulder of the ball lock sleeve 14, the upper inner wall thereof restricts the movement of the steel balls 16, so that it forms an inwardly protruding blocking portion, and when the ball lock sleeve 15 moves upward and the lower expansion hole position moves up to the position of the six steel balls 16, the six steel balls 16 can move freely outward, thereby releasing the blocking of the inner rubber plug 1, and the expansion hole just holds the six steel balls 16.

[0060] Furthermore, the connecting piece 3 of the hanger 26 is connected to the upper vulcanized ring 11 of the annular plug 5 through the copper shear nails 4 , and an O-ring is provided on the connecting piece 3 to seal the connecting piece 3 and the upper vulcanized ring 11 .

[0061] Furthermore, an O-ring groove is provided on the upper part of the lower thread of the lower vulcanized ring 13 to accommodate an O-ring, and the lower vulcanized ring 13 is connected to the ball-locking sleeve 14 through the thread to achieve a sealing effect.

[0062] It can be known from the above description and the accompanying drawings that the upper vulcanized ring 11, the annular rubber 12, the lower vulcanized ring 13, the ball locking sleeve 14, and the ball blocking sleeve 15 are all hollow, forming a cavity of the annular rubber plug 5. The ball blocking sleeve 15 is arranged outside the ball locking sleeve 14, and the ball blocking sleeve 15 can move upward relative to the ball locking sleeve 14 when it is subjected to upward resistance.

[0063] See also Figure 2 The inner rubber plug 1 is composed of the following components: an inner rubber 7, a vulcanized rod 8, an inner rubber plug O-ring 9, and a guide head 10.

[0064] Specifically, the outer wall of the inner rubber 7 is provided with a plurality of wings from top to bottom, which can realize the function of scraping the cement slurry on the inner wall of the oil pipe 25 (or drill pipe, the same below), and also includes a guide head 10 arranged below the inner rubber 7, the lower part of the inner rubber 7 is fixedly connected with the vulcanized rod 8 by vulcanization, and the lower part of the vulcanized rod 8 is threadedly connected with the upper part of the guide head 10. The lower part of the guide head 10 is in an inverted trapezoidal shape, and is provided with an O-ring groove, in which the inner rubber plug O-ring 9 is placed, and a shoulder is provided on the upper part of the guide head 10 to form the clamping part. The inner rubber plug 1 can be clamped in the inner cavity of the annular rubber plug 5 through the contact between the shoulder on the upper part of the guide head 10 and the steel ball 16.

[0065] From the above description and Figure 1 Figure 2 It can be seen that in the composite plug for cementing of the present invention, the outer diameter of the inner plug 1 is not greater than the inner diameter of the annular plug 5, and is smaller than the distance of the blocking portion. Specifically, generally speaking, the outer diameters of the wings of the inner plug 1 and the clamping portion of the inner plug 1 (the shoulder on the guide head 10) are equal, preferably close to the inner diameter of the annular plug 5, and the annular plug 5 is preferably transitionally matched with the inner plug, so that the inner plug 1 can be clamped and penetrated inside the annular plug 5.

[0066] See also Figure 3 The pipe string structure is mainly composed of the following parts, which are respectively from top to bottom: oil pipe 25, hanger 26, completion casing 27, and cementing device 28.

[0067] The oil pipe 25 is connected to the hanger 26 through an oil pipe buckle (or a drill pipe buckle), the hanger 26 is connected to the completion casing 27 through a casing buckle, and the casing 27 is connected to the cementing device 28 through a casing buckle. The completion casing, open hole packer, screen or other downhole devices can be connected below the cementing device 28, but they are not mentioned because they do not affect the description of the present invention. The position of the hanger 26 downhole is within the casing wellbore 29, and the completion casing 27 is within the open hole wellbore 30.

[0068] See also Figure 4 The stopper sleeve 18 is located at the upper end of the cementing device 28, and the receiving tube 22 is located in the middle of the cementing device 28. The inner diameter of the stopper sleeve 18 is not less than the inner diameter of the annular rubber plug 5, and the inner diameter of the receiving tube 22 has a sealing function after matching with the inner rubber plug O-ring 9.

[0069] See also Figure 3 and Figure 4The present application discloses a composite plug for cementing. When in use, the annulus plug 5 is preset in the inner cavity of the hanger 26, and a stopper sleeve 18 and a receiving tube 22 are arranged in the inner cavity of the cementing device 28. When the designed amount of cement slurry is injected into the pipe string, the inner plug 1 is dropped from the wellhead, and the inner plug 1 moves downward with the displacement fluid to scrape the cement slurry on the wall of the oil pipe 25. When it moves to the inner cavity of the hanger 26, its clamping part, that is, the shoulder of the guide head 10, is blocked by the blocking part at the bottom of the annulus plug 5, that is, the steel ball 16 protruding inward, and it cannot continue to move downward. At the same time, the inner plug 1 and the annulus plug 5 form a composite plug. At this time, the pressure in the oil pipe 25 rises to a certain value, and the connection between the annulus plug 5 and the hanger 26 is released, that is, the copper shear nail 4 of the annulus plug 5 is cut off, and the composite plug moves downward with the liquid flow. At this time, the annulus plug 5 plays the role of scraping the cement slurry on the inner wall of the completion casing 27. When the composite rubber plug descends to the cementing device 28, the preset stopper sleeve 18 in the cementing device 28 contacts the lower part of the ball stopper sleeve 15 of the annular rubber plug 5, and the blocking part of the annular rubber plug 5 moves outward to release the blocking. Specifically, the ball stopper sleeve 15 moves upward, and the hole expansion moves to the steel ball 16 and releases the steel ball 16, thereby releasing the blocking of the inner rubber plug 1. At this time, the inner rubber plug 1 can pass through the inner hollow of the annular rubber plug 5. The inner rubber plug 1 continues to descend, and continues to realize the function of scraping the cement slurry on the inner wall of the tool during the downward process. When it reaches the receiving tube 22, the inner rubber plug O-ring 9 below the guide head 10 forms a seal with the inner hole of the receiving tube 22, and the pressure in the casing continues to increase. Under the action of the liquid pressure, the inner rubber plug 1 and the receiving tube 22 cut off the second copper shear nail 21 and descend, and at the same time release the lock block 20, thereby closing the closing sleeve 19 of the cementing device 28, blocking the cement slurry outside the cementing hole 23, thereby completing the cementing process.

[0070] The technical solutions provided by the present invention are not limited to the above-mentioned embodiments. Any technical solutions formed by transformation and substitution using the structure and method of the present invention are within the protection scope of the present invention.

Claims

1. A traversable composite rubber plug for cementing, characterized in that: Including annular rubber plug and inner rubber plug, The annular rubber plug is a rubber plug with a hollow interior, a wing is provided on its outer wall, an inner cavity is provided inside, and a blocking part protruding inward is provided at the lower part of its inner wall, and the blocking part can move outward; The outer wall of the inner rubber plug is provided with wings, and the bottom of the outer wall is provided with a clamping portion protruding outwards; The outer diameter of the inner rubber plug is not greater than the inner diameter of the annular rubber plug, so that the inner rubber plug can enter the inner cavity of the annular rubber plug from the upper part of the annular rubber plug, and the outwardly protruding clamping portion of the inner rubber plug can be clamped on the blocking portion of the annular rubber plug; When the blocking portion of the annular rubber plug moves outward and the blocking is released, the inner rubber plug escapes from the inner cavity of the annular rubber plug and passes through the annular rubber plug.

2. The penetrable composite rubber plug for cementing according to claim 1, characterized in that: The annular rubber plug comprises an upper vulcanized ring, annular rubber, a lower vulcanized ring, a ball locking sleeve, a ball blocking sleeve and a steel ball. The outer wall of the ring glue is provided with a plurality of wings from top to bottom, and the upper and lower parts of the ring glue are respectively vulcanized and fixedly connected with the lower part of the upper vulcanization ring and the upper part of the lower vulcanization ring; The lower end of the lower vulcanized ring is connected to the ball locking sleeve, the outer wall of the ball locking sleeve is provided with a shoulder, the upper part of the ball blocking sleeve is suspended on the shoulder of the ball locking sleeve, and can move upward along the ball locking sleeve; The lower end of the ball lock sleeve is evenly provided with a plurality of ball holes in the circumference, and steel balls are arranged in the ball holes; The inner diameter of the upper part of the ball blocking sleeve is equal to the outer diameter of the ball locking sleeve, and the lower part of the inner wall of the ball blocking sleeve is provided with an expanded hole extending outward, and the inner diameter thereof is larger than the outer diameter of the ball locking sleeve; When the ball blocking sleeve is suspended on the shoulder of the ball locking sleeve, its upper inner wall limits the movement of the steel ball, causing it to protrude inward to form a blocking portion. When the ball blocking sleeve moves upward, the lower expansion hole position moves up to the steel ball position, and the steel ball can move freely outward to release the blockage.

3. The penetrable composite rubber plug for cementing according to claim 2, characterized in that: The inner rubber plug includes an inner rubber, a vulcanized rod, an inner rubber plug O-ring, and a guide head; A plurality of wings are arranged on the outer wall of the inner rubber from top to bottom, the lower part of the inner rubber is fixedly connected to the vulcanization rod by vulcanization, the lower part of the vulcanization rod is threadedly connected to the upper part of the guide head, a shoulder is arranged on the upper part of the guide head to form the clamping part, and the inner rubber plug is clamped in the inner cavity of the annular rubber plug through the contact between the shoulder on the upper part of the guide head and the steel ball.

4. The penetrable composite rubber plug for cementing according to claim 3, characterized in that: The receiving tube located in the middle of the cement injector can be sealed by an inner rubber plug O-ring and a guide head.

5. The penetrable composite rubber plug for cementing according to claim 3, characterized in that: The inner diameter of the ball stopper sleeve of the annular plug is not less than the inner diameter of the stopper sleeve in the cement injector, thereby blocking the annular plug and allowing the ball stopper sleeve to move upward along the locking ball sleeve, and the lower expansion hole position moves up to the steel ball position. The steel ball can move freely outward to release the obstruction to the inner plug.

6. The penetrable composite rubber plug for cementing according to any one of claims 1 to 5, characterized in that: The annular rubber plug and the inner rubber plug are transitionally matched.

7. The penetrable composite rubber plug for cementing according to any one of claims 1 to 5, characterized in that: The upper part of the outer wall of the annular rubber plug is suspended in the inner cavity of the hanger through a copper shear nail and a connecting piece.

8. A method for using the traversable composite rubber plug for cementing according to any one of claims 1 to 7, characterized in that: The inner rubber plug scrapes the cement slurry on the oil pipe wall; The inner rubber plug enters the annulus rubber plug, and the clamping part of the inner rubber plug is clamped on the blocking part of the annulus rubber plug to form a composite rubber plug, which scrapes the cement slurry on the inner wall of the completion casing.

9. The method for using the traversable composite rubber plug for cementing according to claim 8, characterized in that: The step also includes the following steps: the blocking portion of the annulus rubber plug moves outward, and after the blocking is released, the inner rubber plug comes out of the inner cavity of the annulus rubber plug, passes through the annulus rubber plug, continues to scrape the cement slurry on the inner wall of the tool during the downward process, and when it reaches the receiving tube, it moves downward with the receiving tube, releases the locking block, and closes the closing sleeve of the cement injector.

10. A method for using the penetrable composite rubber plug for cementing according to claim 7, characterized in that: include, S1 fixes the annular plug in the cavity of the hanger by means of copper shear nails; When the designed amount of cement slurry is injected into the S2 string, the inner rubber plug is put into the wellhead. The inner rubber plug goes down with the displacement fluid and scrapes the cement slurry on the wall of the oil pipe. S3 When the inner rubber plug descends to the inner cavity of the hanger, the inner rubber plug is blocked by the blocking part at the bottom of the annular rubber plug, and the inner rubber plug and the annular rubber plug form a composite rubber plug; As the pressure in the S4 tubing increases, the copper shear pins of the annulus plug are cut off, and the composite plug flows downward with the fluid, and the annulus plug scrapes the cement slurry on the inner wall of the completion casing; When the S5 composite rubber plug descends to the cementing device, the preset stopper sleeve in the cementing device contacts the annular rubber plug, and at the same time, the blocking part of the annular rubber plug moves outward to release the blocking, and the inner rubber plug passes through the inner hollow of the annular rubber plug; The S6 inner rubber plug continues to scrape the cement slurry on the inner wall of the tool during the downward process; When the S7 inner rubber plug continues to move downward to the receiving tube, its lower end and the inner hole of the receiving tube are sealed, the pressure in the casing continues to increase, and the inner rubber plug and the receiving tube cut off the copper shear nails connected on the receiving tube under the action of the liquid pressure and move downward. At the same time, the locking block is released, the closing sleeve of the cementing device is closed, and the cement slurry is blocked outside the cementing hole to complete the cementing process.

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