Flexible drill rod rubber plug

Abstract

The invention provides a flexible drill rod rubber plug, and belongs to the technical field of oil and gas field tail pipe well cementation, the flexible drill rod rubber plug comprises a core body made of an elastic plastic material, a top cover is arranged above the core body, a contraction cylinder and a socket are sequentially arranged below the core body, and the core body, the top cover and the contraction cylinder are jointly sleeved with a rubber body; a plurality of cone-frustum-shaped inner through cavities are sequentially formed in the core body in the axis direction from bottom to top in a penetrating mode, a plurality of telescopic joints made of hard metal materials are sequentially arranged in the core body in the axis direction, the number of the telescopic joints is consistent with the number of the inner through cavities, and each stage of telescopic joint is arranged in the next stage of telescopic joint in a sliding mode. The height of each stage of telescopic joint is equal, and each stage of telescopic joint is in one-to-one correspondence with the corresponding inner through cavity; when the flexible drill rod rubber plug passes through a coiled tubing wound on a large roller, the core body is elastically bent along the bent coiled tubing, and permanent deformation is avoided.

Description

Technical Field

[0001] The present invention belongs to the technical field of oil and gas well liner cementing, and particularly relates to a flexible drill pipe plug. Background Art

[0002] In the drilling operations of oil and gas fields, the liner cementing process has become the preferred technology for cementing operations in deep wells and ultra-deep wells due to its significant cost-effective advantages. In this process, the liner hanger plays a crucial role, and the drill pipe plug, as an indispensable key component of the hanger, mainly functions to effectively isolate the displacement fluid from the cement slurry and drive the injection of the cement slurry. Once the drill pipe plug fails, it will directly lead to the failure of the cementing operation. During implementation, the drill pipe plug needs to be precisely released so that the bottom of its metal skeleton can smoothly penetrate into the through-hole of the liner plug, thereby achieving the composite self-locking between the drill pipe plug and the liner plug.

[0003] In the existing technical system, the drill pipe plug is formed by compounding a metal skeleton with a rubber material having high wear resistance, oil resistance, and tear resistance through a precise injection vulcanization process under high temperature conditions. To significantly improve the operation efficiency and quality, coiled tubing technology has been widely applied to cementing operations. However, the coiled tubing is often wound around a large roller, and the coiled tubing in this part is in a bent shape. The traditional rigid drill pipe plug is extremely prone to permanent deformation during the penetration process, resulting in permanent damage, bringing great uncertainties to the cementing operation. Therefore, a flexible drill pipe plug is needed. The flexible drill pipe plug will not undergo permanent deformation when passing through the coiled tubing wound around a large roller, and at the same time, the running resistance is greatly reduced, making the cementing reliable and convenient. Summary of the Invention

[0004] Aiming at the deficiencies existing in the prior art, the purpose of the present invention is to provide a flexible drill pipe plug.

[0005] To solve the above technical problems, the present invention is realized through the following technical solutions: A flexible drill pipe plug, characterized in that: it includes a core body made of an elastic plastic material, a top cover is provided above the core body, a shrinkage cylinder and a socket are successively provided below the core body, and a colloid is commonly sleeved outside the core body, the top cover and the shrinkage cylinder; a plurality of large rubber discs and small rubber discs are provided outside the colloid.

[0006] Furthermore, a plurality of conical inner cavities are successively penetrated along the axial direction from bottom to top inside the core body, and the diameter of the upper circular surface of each stage of inner cavity is larger than the diameter of the lower circular surface of the upper stage of inner cavity, and the heights of all inner cavities are equal; a plurality of expansion joints made of hard metal materials are successively provided along the axial direction inside the core body, the number of expansion joints is the same as the number of inner cavities, each stage of expansion joint is slidably arranged in the lower stage of expansion joint, the height of each stage of expansion joint is equal, and each stage of expansion joint corresponds to the corresponding inner cavity one by one.

[0007] Further, an upper convex ring and a lower convex ring are respectively provided on the upper surface and the lower surface of the core body, an upper bite groove matching with the upper convex ring is provided on the lower surface of the top cover, and a lower bite groove matching with the lower convex ring is provided on the upper surface of the shrinkage cylinder.

[0008] Further, a plurality of annular grooves are provided on the cylindrical surface of the core body, and a plurality of annular platforms respectively engaging with the annular grooves are provided on the inner cylindrical surface of the colloid.

[0009] Further, the outer part of each expansion joint is of a tapered table surface structure, the tapered table surface of the expansion joint is consistent with the shape of the corresponding inner through cavity, the expansion joint is successively a cylindrical surface and a cylindrical boss structure below the tapered table surface, a sliding groove is provided around the cylindrical boss, an inner sliding cylindrical surface is provided inside the expansion joint, a neck hole with a diameter smaller than that of the inner sliding cylindrical surface is provided through the upper part of the inner sliding cylindrical surface, four sliding strips are vertically and evenly provided on the inner wall of the inner sliding cylindrical surface, a plurality of blocking grooves are provided at the outer edge of the bottom of the cylindrical boss, a plurality of blocking platforms are provided at the inner edge of the bottom of the cylindrical boss, and the number of the blocking grooves is equal to that of the blocking platforms.

[0010] Further, the cylindrical boss of each stage of expansion joint forms a sliding fit with the inner sliding cylindrical surface of the next stage of expansion joint, the four sliding grooves of each stage of expansion joint respectively form a sliding fit with the four sliding strips of the next stage of expansion joint, the diameter of the cylindrical surface of each stage of expansion joint is the same as the diameter of the neck hole of the next stage of expansion joint, and the blocking groove of each stage of expansion joint is adapted to the blocking platform of the next stage of expansion joint; four locking sliding grooves are provided at the bottom of the cylindrical boss of the expansion joint, a locking sliding block is slidably provided in the locking sliding grooves, a locking pin extending to the outside of the cylindrical boss is provided on the side surface of the locking sliding block, a locking spring is connected between the locking sliding block and the inner wall of the locking sliding grooves, and four locking holes respectively adapted to the four locking pins on the next stage of expansion joint are provided through between the tapered table surface and the inner sliding cylindrical surface of each stage of expansion joint.

[0011] Further, a shrinkage cavity is provided inside the shrinkage cylinder, a shrinkage neck hole with a diameter smaller than that of the shrinkage cavity is provided through the upper part of the shrinkage cavity, the shrinkage cavity forms a sliding fit with the cylindrical boss of the lowermost stage of expansion joint, the diameter of the shrinkage neck hole is the same as the diameter of the cylindrical surface of the lowermost stage of expansion joint, four shrinkage sliding strips are evenly provided on the inner wall of the shrinkage cavity of the shrinkage cylinder, the four shrinkage sliding strips respectively form a sliding fit with the sliding grooves of the lowermost stage of expansion joint, a shrinkage blocking platform adapted to the blocking groove of the lowermost stage of expansion joint is provided inward at the bottom of the shrinkage cavity, four limiting holes respectively adapted to the four locking pins on the lowermost stage of expansion joint are provided through on the shrinkage cavity, and the height of the shrinkage cylinder is equal to the height of the expansion joint.

[0012] Further, an inner cover cavity is provided in the middle of the top cover. A top cover through hole communicating with the inner cover cavity is provided on the lower surface of the top cover. Four top cover slideways are evenly provided on the inner wall of the inner cover cavity. A top lock bar is slidably provided in each of the four top cover slideways. A frustum is provided on the top lock bar. A top spring is connected between the inner wall of the inner cover cavity and the frustum. One end of the top lock bar facing the central axis of the top cover is a limit platform. A top lock arc surface is provided on the top lock bar between the frustum and the limit platform. A top lock block is provided at the top of the uppermost telescopic section. The diameter of the top lock block is equal to the diameter of the top cover through hole. Four top lock grooves for clamping the four top lock bars respectively are evenly provided on the cylindrical surface of the top lock block. A lock position inclined surface for driving the limit platform is provided on the upper part of the top lock block. A through hole is provided along the axis in the top lock block. A sealing connection block is provided at the bottom of the inner sliding cylindrical surface of the uppermost telescopic section. A main spring is provided between the sealing connection block and the upper surface of the inner cover cavity of the top cover, and the main spring passes through the inner sliding cylindrical surfaces, neck holes and through holes of all telescopic sections.

[0013] Further, the lower part of the socket is a circular inclined surface. Four socket slideways are evenly provided on the cylindrical surface of the socket and above the circular inclined surface. A driving slide bar is slidably provided in each of the four socket slideways. One end of the driving slide bar is a driving inclined surface extending to the outside of the socket. A limit block is provided on the upper part of the other end of the driving slide bar, and the limit block is located inside the socket. A limit spring is connected between the socket and the driving slide bar. A lower limit disk is provided on the upper part of the limit block. Four limit grooves for clamping the limit block respectively are evenly provided on the lower surface of the lower limit disk. A connecting block is connected to the upper surface of the lower limit disk. A high limit disk is connected to the upper surface of the connecting block. Two side support plates are symmetrically provided on the side surface of the high limit disk. Two arc rods are symmetrically provided between the two side support plates. A side sliding seat is slidably provided on each arc rod, and the side sliding seat is fixedly provided on the inner wall of the socket. Arc springs are sleeved on the outer parts of the arc rods respectively, and two ends of each arc spring are connected with the side support plate and the side sliding seat respectively. A clamping platform is provided at the bottom of the sealing connection block. A clamping hole for clamping the clamping platform is provided in the middle of the high limit disk, and the thickness of the clamping platform is less than the height of the connecting block.

[0014] Further, the core body is made of an elastic steel wire rope material. A round hole connected to the core body is provided below the top cover, and a round hole connected to the core body is provided above the shrinkage cylinder.

[0015] The beneficial effects of the present invention compared with the prior art are as follows: (1) When the flexible drill pipe rubber plug of the present invention passes through the coiled tubing wound around a large roller, the core body bends elastically along the curved coiled tubing, and the colloid also bends along with the core body. Therefore, the flexible drill pipe rubber plug can smoothly pass through the curved section of the coiled tubing. When the flexible drill pipe rubber plug reaches the straight section of the coiled tubing, the core body automatically returns to the straight state, and the colloid also returns to the straight state along with the core body. Therefore, the flexible drill pipe rubber plug will not undergo permanent deformation.

[0016] (2) During the insertion of the flexible drill pipe rubber plug of the present invention into the liner rubber plug, the socket first enters the through hole of the liner rubber plug. Subsequently, the upper chord edge of the liner rubber plug contacts the driving slide bars and the driving inclined surfaces, so that the four driving slide bars are simultaneously squeezed to slide towards the center. The clamping holes are disengaged from the clamping platforms, and the main spring provides a pulling force to pull the uppermost telescopic joint upwards. Finally, the socket, the contraction cylinder, all the telescopic joints, the top locking block and the top cover are rigidly connected together. At the same time, the conical table surfaces of each telescopic joint are closely attached to the corresponding inner through cavities, and the top surfaces of the telescopic joints also contact and fit with the top surfaces on the inner through cavities. Therefore, the core body can no longer undergo elastic bending. Thus, under the action of the oil well pressure, the flexible drill pipe rubber plug can smoothly enter the liner rubber plug.

[0017] (3) The four driving slide bars of the present invention do not contact the inner wall of the coiled tubing simultaneously. Therefore, the four limiting grooves on the low limiting disc do not lose their limiting functions simultaneously. When the socket touches the coiled tubing, the limiting spring provides an elastic force to make the limiting blocks on the driving slide bars re-insert into the corresponding limiting grooves. Therefore, the flexible drill pipe rubber plug has an anti-mis-touch function when passing through the coiled tubing. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a schematic structural diagram of the front of the present invention.

[0019] Figure 2 is a schematic structural diagram of the overall cross-section of the first embodiment of the present invention.

[0020] Figure 3 is a schematic structural diagram of the connection of the top cover, the contraction cylinder and the socket of the present invention.

[0021] Figure 4 is a schematic structural diagram of the cross-section of the colloid of the present invention.

[0022] Figure 5 is a schematic structural diagram of the cross-section of the core body of the present invention.

[0023] Figure 6 is a schematic structural diagram of the connection of the telescopic joints of the present invention.

[0024] Figure 7 is a schematic top view structural diagram of the telescopic joint of the present invention.

[0025] Figure 8 is a schematic bottom view structural diagram of the telescopic joint of the present invention.

[0026] Figure 9 is Figure 8 the partial enlarged view at B in

[0027] Figure 10 is a schematic top view structural diagram of the contraction cylinder of the present invention.

[0028] Figure 11 is a schematic bottom view structural diagram of the contraction cylinder of the present invention.

[0029] Figure 12 It is a schematic structural diagram of the cross-section of the top cover of the present invention.

[0030] Figure 13 It is a schematic structural diagram of the installation of the top lock bar of the present invention.

[0031] Figure 14 It is a schematic structural diagram of the top lock bar of the present invention.

[0032] Figure 15 It is a schematic structural diagram of the installation of the top lock block of the present invention.

[0033] Figure 16 It is a schematic structural diagram of the installation of the sealing and connecting block and the clamping table of the present invention.

[0034] Figure 17 is Figure 2 The partial enlarged view at A in

[0035] Figure 18 It is a schematic structural diagram of the socket of the present invention.

[0036] Figure 19 It is a schematic structural diagram of the interior of the socket of the present invention.

[0037] Figure 20 It is a schematic structural diagram of the installation of the low limit disc of the present invention.

[0038] Figure 21 It is a schematic exploded structural diagram of the installation of the low limit disc of the present invention.

[0039] Figure 22 It is a schematic structural diagram of the installation of the high limit disc, side support plate and arc rod of the present invention.

[0040] Figure 23 It is a schematic structural diagram of the overall cross-section of the second embodiment of the present invention.

[0041] Reference numerals: 1 - core body; 101 - internal through cavity; 102 - upper convex ring; 103 - lower convex ring; 104 - annular groove; 2 - top cover; 201 - upper bite groove; 202 - internal cover cavity; 203 - top cover through hole; 204 - top cover slideway; 3 - shrinkage cylinder; 301 - lower bite groove; 302 - shrinkage cavity; 303 - shrinkage neck hole; 304 - shrinkage slide bar; 305 - limiting hole; 306 - shrinkage retaining table; 4 - socket; 401 - circular inclined surface; 402 - socket slideway; 5 - colloid; 501 - annular platform; 6 - expansion joint; 601 - conical surface; 602 - cylindrical surface; 603 - cylindrical boss; 604 - chute; 605 - internal sliding cylindrical surface; 606 - neck hole; 607 - slide bar; 608 - blocking groove; 609 - blocking table; 610 - locking chute; 611 - locking hole; 7 - locking slider; 8 - locking pin; 9 - locking spring; 10 - top locking bar; 1001 - frustum; 1002 - limiting table; 1003 - top locking arc surface; 11 - top spring; 12 - top locking block; 1201 - top locking groove; 1202 - locking position inclined surface; 1203 - through hole; 13 - sealing and connecting block; 14 - main spring; 15 - driving slide bar; 1501 - driving inclined surface; 16 - limiting block; 17 - limiting spring; 18 - lower limiting disc; 19 - limiting groove; 20 - connecting block; 21 - upper limiting disc; 2101 - clamping hole; 22 - side support plate; 23 - arc rod; 24 - side sliding seat; 25 - arc spring; 26 - clamping table. Detailed implementation mode

[0042] In the present invention, unless otherwise stated, the orientations such as "upper" and "lower" are usually in the directions shown in the drawings, or in the vertical, perpendicular or gravitational directions; similarly, for the convenience of understanding and description, "left" and "right" are usually the left and right shown in the drawings; "inside" and "outside" refer to the inside and outside relative to the contours of the respective components, but the above orientation terms are not used to limit the present invention.

[0043] Embodiment 1: Please refer to Figures 1 - 22 the structural schematic diagram. The present invention provides the following technical solutions: A flexible drill pipe rubber plug includes a core body 1 made of an elastic material. The optional elastic material is polycarbonate. A top cover 2 is provided above the core body 1. A shrinkage cylinder 3 and a socket 4 are sequentially provided below the core body 1. The core body 1, the top cover 2 and the shrinkage cylinder 3 are commonly sleeved with a colloid 5 outside. Multiple large rubber discs and small rubber discs for sealing with the liner rubber plug are provided outside the colloid 5.

[0044] Specifically, the upper part of the colloid 5 overlaps with the top cover 2, and the lower part of the colloid 5 overlaps with the shrinkage cylinder 3. When the flexible drill pipe rubber plug and the liner rubber plug are compounded and self-locked, the socket 4 first enters the liner rubber plug; when the flexible drill pipe rubber plug passes through the coiled tubing wound around the large roller, the core 1 elastically bends along the curved coiled tubing, and the colloid 5 also bends along with the core 1. Therefore, the flexible drill pipe rubber plug can smoothly pass through the bent section of the coiled tubing. When the flexible drill pipe rubber plug reaches the straight section of the coiled tubing, the core 1 automatically returns to the straight state, and the colloid 5 also returns to the straight state along with the core 1. Therefore, the flexible drill pipe rubber plug will not undergo permanent deformation.

[0045] Considering that if the drill pipe rubber plug solution with a completely flexible design is adopted, although the deformation problem during operation in the coiled tubing can be solved, at the critical moment when forming a compound self-locking structure with the liner rubber plug, under the action of the oil well pressure, the purely flexible drill pipe rubber plug may bend under pressure and it is difficult to smoothly embed into the inner part of the liner rubber plug. Therefore, at the moment when the drill pipe rubber plug contacts the liner rubber plug, the drill pipe rubber plug needs to have the ability to instantaneously convert to a rigid state to ensure that it can accurately complete the self-locking process.

[0046] Inside the core 1, a plurality of conical frustum-shaped inner through cavities 101 are sequentially arranged along the axial direction from bottom to top, and the diameter of the upper circular surface of each inner through cavity 101 is larger than the diameter of the lower circular surface of the upper-level inner through cavity 101, and the heights of all the inner through cavities 101 are equal.

[0047] An upper convex ring 102 and a lower convex ring 103 are respectively arranged on the upper surface and the lower surface of the core 1. A upper biting groove 201 matching the upper convex ring 102 is arranged on the lower surface of the top cover 2, and a lower biting groove 301 matching the lower convex ring 103 is arranged on the upper surface of the shrinkage cylinder 3, making the connection between the core 1 and the top cover 2 and the connection between the core 1 and the shrinkage cylinder 3 more firm.

[0048] A plurality of annular grooves 104 are arranged on the cylindrical surface of the core 1, and a plurality of annular platforms 501 respectively engaging with the annular grooves 104 are arranged on the inner cylindrical surface of the colloid 5, making the colloid 5 sleeved outside the core 1, the top cover 2 and the shrinkage cylinder 3 not easy to fall off.

[0049] Inside the core body 1, a plurality of expansion joints 6 made of hard metal materials are sequentially arranged along the axial direction. The optional hard metal material is cemented carbide material added with tungsten. The number of expansion joints 6 is the same as the number of internal through cavities 101. Each stage of expansion joint 6 is slidably arranged in the next stage of expansion joint 6. The height of each stage of expansion joint 6 is equal, and each stage of expansion joint 6 corresponds to the corresponding internal through cavity 101 one by one. The outer part of each expansion joint 6 is a tapered table surface 601 structure. The tapered table surface 601 of the expansion joint 6 is the same as the shape of the corresponding internal through cavity 101. Below the tapered table surface 601 of the expansion joint 6 are sequentially a cylindrical surface 602 and a cylindrical boss 603 structure. A chute 604 is provided around the cylindrical boss 603. An internal sliding cylindrical surface 605 is provided inside the expansion joint 6. A neck hole 606 with a diameter smaller than that of the internal sliding cylindrical surface 605 is provided through the upper part of the internal sliding cylindrical surface 605. Four slide bars 607 are evenly and vertically provided on the inner wall of the internal sliding cylindrical surface 605. A plurality of blocking grooves 608 are provided at the outer edge of the bottom of the cylindrical boss 603. A plurality of blocking platforms 609 are provided at the inner edge of the bottom of the cylindrical boss 603. The number of blocking grooves 608 and blocking platforms 609 is equal.

[0050] The cylindrical boss 603 of each stage of expansion joint 6 forms a sliding fit with the internal sliding cylindrical surface 605 of the next stage of expansion joint 6. The four chutes 604 of each stage of expansion joint 6 respectively form a sliding fit with the four slide bars 607 of the next stage of expansion joint 6, ensuring that the expansion joint 6 only slides up and down without rotating. The diameter of the cylindrical surface 602 of each stage of expansion joint 6 is the same as the diameter of the neck hole 606 of the next stage of expansion joint 6. The blocking groove 608 of each stage of expansion joint 6 is adapted to the blocking platform 609 of the next stage of expansion joint 6. When all the expansion joints 6 slide to the lower position, the cylindrical boss 603 of each stage of expansion joint 6 slides to a position flush with the cylindrical boss 603 of the next stage of expansion joint 6. The blocking groove 608 of each stage of expansion joint 6 enters the corresponding blocking platform 609 of the next stage of expansion joint 6, preventing the expansion joint 6 from sliding out from below the next stage of expansion joint 6. Since the heights of all the expansion joints 6 are quite the same, each stage of expansion joint 6 slides into the interior of the next stage of expansion joint 6. When all the expansion joints 6 slide to the upper position, the upper surface of the cylindrical boss 603 of each stage of expansion joint 6 contacts the upper surface of the internal sliding cylindrical surface 605 of the next stage of expansion joint 6, thereby preventing each stage of expansion joint 6 from sliding out from above the next stage of expansion joint 6. The cylindrical surface 602 of each stage of expansion joint 6 slides into the neck hole 606 of the next stage of expansion joint 6, making the connection between two adjacent expansion joints 6 more firm; at the same time, the tapered table surface 601 of each stage of expansion joint 6 is in close fit with the corresponding internal through cavity 101, and the top surface of the expansion joint 6 also contacts and fits with the top surface of the internal through cavity 101, so that the core body 1 no longer undergoes elastic bending.

[0051] Considering that when all the expansion joints 6 slide to the upper position, it is necessary to prevent the expansion joints 6 from sliding down further. Therefore, four locking chute grooves 610 are provided at the bottom of the cylindrical boss 603 of the expansion joint 6. A locking slider 7 is slidably arranged in the locking chute grooves 610. A locking pin 8 extending to the outside of the cylindrical boss 603 is provided on the side of the locking slider 7. A locking spring 9 is connected between the inner wall of the locking slider 7 and the locking chute grooves 610. Four locking holes 611 respectively adapted to the four locking pins 8 on the next-level expansion joint 6 are provided through between the conical surface 601 and the inner sliding cylindrical surface 605 of each level of expansion joint 6.

[0052] Specifically, when the expansion joint 6 is in the lower position, the locking pins 8 on each level of expansion joint 6 are in contact with the inner sliding cylindrical surface 605 of the next-level expansion joint 6. Therefore, the locking pins 8 do not pop out of the locking chute grooves 610, and the locking spring 9 is in a compressed state. When the expansion joint 6 moves to the upper position, the locking pins 8 on each level of expansion joint 6 coincide with the locking holes 611 of the next-level expansion joint 6. The locking spring 9 provides an elastic force to insert the locking pins 8 on each level of expansion joint 6 into the locking holes 611 of the next-level expansion joint 6. The end face of the locking pin 8 is a chamfered surface, which is convenient for the locking pin 8 to be inserted into the corresponding locking hole 611. Therefore, two adjacent expansion joints 6 are locked together, thereby preventing the expansion joint 6 from sliding down.

[0053] Considering that when the core body 1 is in an elastic state, the lowermost-level expansion joint 6 also needs to be disengaged from the corresponding inner through cavity 101. Therefore, a contraction cavity 302 is provided inside the contraction cylinder 3. A contraction neck hole 303 with a diameter smaller than that of the contraction cavity 302 is provided through the upper part of the contraction cavity 302. The contraction cavity 302 forms a sliding fit with the cylindrical boss 603 of the lowermost-level expansion joint 6. The diameter of the contraction neck hole 303 is the same as the diameter of the cylindrical surface 602 of the lowermost-level expansion joint 6. Four contraction slide bars 304 are evenly provided on the inner wall of the contraction cavity 302 of the contraction cylinder 3. The four contraction slide bars 304 respectively form a sliding fit with the chute grooves 604 of the lowermost-level expansion joint 6. A contraction stop platform 306 adapted to the blocking groove 608 of the lowermost-level expansion joint 6 is provided inward at the bottom of the contraction cavity 302. Four limiting holes 305 respectively adapted to the four locking pins 8 on the lowermost-level expansion joint 6 are provided through the contraction cavity 302. The height of the contraction cylinder 3 is equal to the height of the expansion joint 6.

[0054] Specifically, when the lowermost expansion joint 6 is in the lower position, the lower surface of the lowermost expansion joint 6 is flush with the lower surface of the contraction cylinder 3, and the blocking groove 608 of the lowermost expansion joint 6 enters the corresponding contraction blocking platform 306 of the contraction cylinder 3, preventing the lowermost expansion joint 6 from sliding out from below the contraction cylinder 3, that is, the lowermost expansion joint 6 slides into the interior of the contraction cylinder 3. Therefore, when all the expansion joints 6 are in the lower position, all the expansion joints 6 can be located in the contraction cavity 302 of the contraction cylinder 3. As a result, all the expansion joints 6 no longer contact the corresponding inner through cavity 101, and the core body 1 is in an elastic state. When the lowermost expansion joint 6 slides to the upper position, the upper surface of the cylindrical boss 603 of the lowermost expansion joint 6 contacts the upper surface of the contraction cavity 302 of the contraction cylinder 3, thus preventing the lowermost expansion joint 6 from sliding out of the contraction cylinder 3. The cylindrical surface 602 of the lowermost expansion joint 6 slides into the contraction neck hole 303, making the connection between the lowermost expansion joint 6 and the contraction cylinder 3 more firm. The conical table surface 601 of the lowermost expansion joint 6 is in close fit with the corresponding inner through cavity 101. At the same time, in accordance with the above principle, the locking pin 8 on the lowermost expansion joint 6 is inserted into the limiting hole 305 of the contraction cylinder 3.

[0055] Considering that when the expansion joint 6 is in the upper position, in order to ensure that the drill pipe rubber plug is no longer bent, the uppermost expansion joint 6 needs to be connected to the top cover 2. Therefore, an inner cover cavity 202 is provided in the middle of the top cover 2, and a top cover through hole 203 communicating with the inner cover cavity 202 is provided on the lower surface of the top cover 2. Four top cover slide ways 204 are evenly provided on the inner wall of the inner cover cavity 202. A top locking bar 10 is slidably provided in each of the four top cover slide ways 204. A round table 1001 is provided on the top locking bar 10. A top spring 11 is connected between the inner wall of the inner cover cavity 202 and the round table 1001. One end of the top locking bar 10 facing the central axis of the top cover 2 is a limiting platform 1002. A top locking arc surface 1003 is provided on the top locking bar 10 between the round table 1001 and the limiting platform 1002.

[0056] The top of the uppermost expansion joint 6 is provided with a top locking block 12. The cylindrical arc surface of the top locking block 12 has the same radian as the side surface of the limiting platform 1002. The diameter of the top locking block 12 is equal to the diameter of the top cover through hole 203. Four top locking grooves 1201 for respectively clamping the four top locking bars 10 are evenly provided on the cylindrical surface of the top locking block 12. A locking position inclined surface 1202 for driving the limiting platform 1002 is provided on the upper part of the top locking block 12. A through hole 1203 is provided along the axis in the top locking block 12.

[0057] Specifically, when all the expansion joints 6 slide to the upper position, the top locking block 12 is inserted into the top cover through hole 203. The locking position inclined surface 1202 facilitates the insertion of the top locking block 12. During the insertion process of the top locking block 12, the locking position inclined surface 1202 contacts the top locking arc surface 1003, driving the top locking bar 10 to move outward, and the top spring 11 compresses and stores energy. When the top locking arc surface 1003 of the top locking bar 10 coincides with the top locking groove 1201, the top spring 11 provides elastic force, enabling the top locking arc surface 1003 of the top locking bar 10 to be inserted into the top locking groove 1201, and the limiting platform 1002 contacts the cylindrical arc surface of the top locking block 12. Therefore, a rigid connection is formed among the uppermost expansion joint 6, the top locking block 12, and the top cover 2.

[0058] At the bottom of the inner sliding cylindrical surface 605 of the uppermost expansion joint 6, there is a sealing connection block 13. Between the sealing connection block 13 and the upper surface of the inner cover cavity 202 of the top cover 2, there is a main spring 14, and the main spring 14 passes through the inner sliding cylindrical surfaces 605, neck holes 606 of all the expansion joints 6, and the through hole 1203 of the top locking block 12. When all the expansion joints 6 are in the lower position, the main spring 14 is in a stretched and energy-stored state, providing power for the expansion joints 6 to move to the upper position.

[0059] Below the socket 4 is a circular inclined surface 401. On the cylindrical surface of the socket 4 and above the circular inclined surface 401, four socket slideways 402 are evenly arranged. In each of the four socket slideways 402, there is a driving slide bar 15 sliding. One end of the driving slide bar 15 is an inclined surface 1501 extending to the outside of the socket 4, and on the upper part of the other end of the driving slide bar 15, there is a limiting block 16, and the limiting block 16 is located inside the socket 4. Between the socket 4 and the driving slide bar 15, there is a limiting spring 17. On the upper part of the limiting block 16, there is a low limiting disc 18. On the lower surface of the low limiting disc 18, four limiting grooves 19 for clamping the limiting block 16 are evenly arranged. On the upper surface of the low limiting disc 18, there is a connecting block 20 connected. On the upper surface of the connecting block 20, there is a high limiting disc 21 connected. On the side surface of the high limiting disc 21, two side support plates 22 are symmetrically arranged. Between the two side support plates 22, two arc rods 23 are symmetrically arranged. On each of the arc rods 23, there is a side sliding seat 24 sliding. The side sliding seat 24 is fixedly arranged on the inner wall of the socket 4. On the outside of each of the arc rods 23, there is an arc spring 25 sleeved. The two ends of the arc spring 25 are respectively connected with the side support plate 22 and the side sliding seat 24.

[0060] At the bottom of the sealing connection block 13, there is a clamping platform 26. In the middle of the high limiting disc 21, there is a clamping hole 2101 for clamping the clamping platform 26, and the thickness of the clamping platform 26 is less than the height of the connecting block 20.

[0061] Specifically, when the expansion joint 6 is in the lower position, the clamping platform 26 is inserted into the clamping hole 2101, and the clamping hole 2101 tightly clamps and locks the clamping platform 26. When the drill pipe rubber plug is inserted into the liner rubber plug, the circular inclined surface 401 of the socket 4 facilitates the coincidence of the socket 4 with the through hole of the liner rubber plug. The socket 4 enters the through hole of the liner rubber plug. Subsequently, the upper chord edge of the liner rubber plug contacts the driving slide bars 15 and the driving inclined surfaces 1501, so the four driving slide bars 15 are simultaneously squeezed to slide towards the center. Therefore, the four limiting blocks 16 are simultaneously disengaged from the limiting grooves 19. The arc spring 25 provides a pulling force, enabling the arc rod 23 to slide in the side sliding seat 24. Thus, the high limiting disc 21 rotates, and the clamping hole 2101 is disengaged from the clamping platform 26.

[0062] When the flexible drill pipe rubber plug passes through the coiled tubing, the socket 4 will touch the inner wall of the coiled tubing. Since the inner diameter of the coiled tubing is larger than the diameter of the socket 4, the four driving slide bars 15 on the socket 4 will not simultaneously contact the inner wall of the coiled tubing. Therefore, the four limiting grooves 19 on the low limiting disc 18 will not simultaneously lose their limiting function. After the socket 4 touches the coiled tubing, the limiting spring 17 provides an elastic force, enabling the limiting blocks 16 on the driving slide bars 15 to re-insert into the corresponding limiting grooves 19. Therefore, the flexible drill pipe rubber plug has an anti-mis-touch function when passing through the coiled tubing.

[0063] The working principle of this embodiment is as follows: When releasing the flexible drill pipe rubber plug into the coiled tubing, all the expansion joints 6 are in the lower position. The clamping platform 26 is inserted into the clamping hole 2101 of the high limiting disc 21, and the clamping hole 2101 tightly clamps and locks the clamping platform 26. The clamping platform 26 makes the uppermost expansion joint 6 in the lower position through the sealing connection block 13. The blocking groove 608 of each stage of the expansion joint 6 enters the corresponding blocking platform 609 of the next stage of the expansion joint 6, preventing the expansion joint 6 from sliding out from below the next stage of the expansion joint 6. The blocking groove 608 of the lowermost expansion joint 6 enters the corresponding contraction blocking platform 306 of the contraction cylinder 3, preventing the lowermost expansion joint 6 from sliding out from below the contraction cylinder 3. Therefore, all the expansion joints 6 are located in the contraction cavity 302 of the contraction cylinder 3, and the expansion joints 6 do not act on the inner through cavity 101. When the flexible drill pipe rubber plug passes through the coiled tubing wound around the large roller, the core body 1 elastically bends along the curved coiled tubing, and the colloid 5 also bends along with the core body 1. Therefore, the flexible drill pipe rubber plug can smoothly pass through the curved section of the coiled tubing. When the flexible drill pipe rubber plug reaches the straight section of the coiled tubing, the core body 1 automatically returns to the straight state, and the colloid 5 also returns to the straight state along with the core body 1. Therefore, the flexible drill pipe rubber plug will not undergo permanent deformation.

[0064] When the flexible drill pipe rubber plug is inserted into the liner rubber plug, the circular inclined surface 401 of the socket 4 facilitates the coincidence of the socket 4 with the through hole of the liner rubber plug. The socket 4 first enters the through hole of the liner rubber plug. Subsequently, the upper chord edge of the liner rubber plug contacts the driving slide bar 15 and the driving inclined surface 1501, so the four driving slide bars 15 are simultaneously squeezed to slide towards the center. Therefore, the four limiting blocks 16 are simultaneously disengaged from the limiting grooves 19. The arc spring 25 provides a pulling force, enabling the arc rod 23 to slide in the side sliding seat 24. Thus, the high limiting disc 21 rotates, and the clamping hole 2101 is disengaged from the clamping platform 26.

[0065] The main spring 14 provides a pulling force to pull the uppermost telescopic joint 6 upwards. The cylindrical convex platform 603 of the uppermost telescopic joint 6 slides in the inner sliding cylindrical surface 605 of the lower-level telescopic joint. When the upper surface of the cylindrical convex platform 603 of the uppermost telescopic joint 6 contacts the upper surface of the inner sliding cylindrical surface 605 of the lower-level telescopic joint, it prevents the uppermost telescopic joint 6 from sliding out from above the lower-level telescopic joint 6. At the same time, the locking pin 8 on the uppermost telescopic joint 6 coincides with the locking hole 611 of the lower-level telescopic joint 6. The locking spring 9 provides an elastic force to insert the locking pin 8 on the uppermost telescopic joint 6 into the locking hole 611 of the lower-level telescopic joint 6, thereby rigidly connecting the uppermost telescopic joint 6 and the lower-level telescopic joint 6 together. By the same principle, all the telescopic joints 6 are rigidly connected together, and the lowermost telescopic joint 6 is rigidly connected to the contraction cylinder 3.

[0066] When the uppermost telescopic joint 6 moves to the upper position, the top locking block 12 is inserted into the through hole 203 of the top cover. The locking inclined surface 1202 facilitates the insertion of the top locking block 12. During the insertion process of the top locking block 12, the locking inclined surface 1202 contacts the top locking arc surface 1003, driving the top locking bar 10 to move outwards, and the top spring 11 is compressed and stores energy. When the top locking arc surface 1003 of the top locking bar 10 coincides with the top locking groove 1201, the top spring 11 provides an elastic force to insert the top locking arc surface 1003 of the top locking bar 10 into the top locking groove 1201. The limiting platform 1002 contacts the cylindrical arc surface of the top locking block 12. Therefore, a rigid connection is formed among the uppermost telescopic joint 6, the top locking block 12, and the top cover 2.

[0067] In summary, the socket 4, the contraction cylinder 3, all the telescopic joints 6, the top locking block 12, and the top cover 2 are rigidly connected together. At the same time, the conical table surface 601 of each telescopic joint 6 is closely attached to the corresponding inner through cavity 101, and the top surface of the telescopic joint 6 also contacts and fits with the top surface on the inner through cavity 101. Therefore, the core body 1 can no longer undergo elastic bending. Thus, under the action of the oil well pressure, the flexible drill pipe rubber plug can smoothly enter the liner rubber plug.

[0068] Embodiment 2: Please refer to Figure 23Schematic structural diagram, the present invention provides the following technical solution: A flexible drill pipe rubber plug includes a core body 1 made of an elastic material. Above the core body 1, there is a top cover 2. Below the core body 1, there are successively arranged a shrinkage cylinder 3 and a socket 4. The core body 1, the top cover 2, and the outside of the shrinkage cylinder 3 are commonly sleeved with a colloid 5. Multiple large rubber discs and small rubber discs are arranged outside the colloid 5. The core body 1 is made of an elastic steel wire rope material. There is a round hole connected to the core body 1 below the top cover 2. The upper end of the core body 1 extends into the round hole below the top cover 2 for pressing. There is a round hole connected to the core body 1 above the shrinkage cylinder 3. The lower end of the core body 1 extends into the round hole above the shrinkage cylinder 3 for pressing. When the flexible drill pipe rubber plug passes through the coiled tubing wound around a large roller, the core body 1 bends elastically along the curved coiled tubing, and the colloid 5 also bends along with the core body 1. Therefore, the flexible drill pipe rubber plug can smoothly pass through the curved section of the coiled tubing. When the flexible drill pipe rubber plug reaches the straight section of the coiled tubing, the core body 1 automatically returns to the straight state, and the colloid 5 also returns to the straight state along with the core body 1. Therefore, the flexible drill pipe rubber plug will not undergo permanent deformation.

[0069] The above are only specific embodiments of the present invention, but the technical features of the present invention are not limited thereto. Any simple changes, equivalent replacements, or modifications made based on the present invention to solve substantially the same technical problems and achieve substantially the same technical effects are all covered by the protection scope of the present invention.

Claims

1. A flexible drill pipe plug, characterized in that: The invention comprises a core body (1) made of elastic material, a top cover (2) being provided above the core body (1), a shrinking tube (3) and a socket (4) being provided in sequence below the core body (1), a colloid (5) being sleeved on the outside of the core body (1), the top cover (2) and the shrinking tube (3), and a plurality of large and small colloid discs being provided on the outside of the colloid (5).

2. A flexible drill pipe plug according to claim 1, characterized in that: The core (1) is provided with a plurality of truncated cone-shaped internal through cavities (101) sequentially penetrating the interior of the core (1) from bottom to top along the axial direction, and the diameter of the upper circular surface of each level of the internal through cavity (101) is greater than the diameter of the lower circular surface of the previous level of the internal through cavity (101), and the heights of all the internal through cavities (101) are equal; The core body (1) is provided with a plurality of telescopic joints (6) made of hard metal material in sequence along the axial direction. The number of the telescopic joints (6) is consistent with the number of the internal through cavities (101). Each level of the telescopic joints (6) is slidably arranged in the next level of the telescopic joints (6). The heights of each level of the telescopic joints (6) are equal, and each level of the telescopic joints (6) corresponds one-to-one to the corresponding internal through cavities (101).

3. A flexible drill pipe plug according to claim 2, characterized in that: An upper convex ring (102) and a lower convex ring (103) are respectively provided on the upper surface and the lower surface of the core body (1), an upper bite groove (201) matching the upper convex ring (102) is provided on the lower surface of the top cover (2), and a lower bite groove (301) matching the lower convex ring (103) is provided on the upper surface of the shrink tube (3).

4. A flexible drill pipe plug according to claim 2, characterized in that: The cylindrical surface of the core (1) is provided with a plurality of annular grooves (104), and the inner cylindrical surface of the colloid (5) is provided with a plurality of annular platforms (501) respectively engaging with the annular grooves (104).

5. A flexible drill pipe plug according to claim 2, characterized in that: The outside of each telescopic joint (6) is a conical surface (601) structure, and the conical surface (601) of the telescopic joint (6) is consistent with the shape of the corresponding inner cavity (101). The telescopic joint (6) is provided with a cylindrical surface (602) and a cylindrical boss (603) structure below the conical surface (601). The cylindrical boss (603) is provided with sliding grooves (604) around it. The inside of the telescopic joint (6) is provided with an inner sliding cylindrical surface (605). The upper part of the inner sliding cylindrical surface (605) is provided with a neck hole (606) with a diameter smaller than that of the inner sliding cylindrical surface (605). The inner wall of the inner sliding cylindrical surface (605) is evenly and vertically provided with four sliding strips (607). A plurality of blocking grooves (608) are provided at the outer edge of the bottom of the cylindrical boss (603), and a plurality of blocking platforms (609) are provided at the inner edge of the bottom of the cylindrical boss (603). The number of blocking grooves (608) and blocking platforms (609) is equal.

6. A flexible drill pipe plug according to claim 5, characterized in that: The cylindrical boss (603) of each telescopic section (6) forms a sliding fit with the inner sliding cylindrical surface (605) of the next telescopic section (6), the four sliding grooves (604) of each telescopic section (6) respectively form a sliding fit with the four sliding strips (607) of the next telescopic section (6), the diameter of the cylindrical surface (602) of each telescopic section (6) is consistent with the diameter of the neck hole (606) of the next telescopic section (6), and the blocking groove (608) of each telescopic section (6) is adapted to the blocking platform (609) of the next telescopic section (6); Four locking grooves (610) are provided at the bottom of the cylindrical boss (603) of the telescopic joint (6), a locking slider (7) is slidably provided in the locking groove (610), a locking pin (8) extending to the outside of the cylindrical boss (603) is provided on the side of the locking slider (7), a locking spring (9) is connected between the locking slider (7) and the inner wall of the locking groove (610), and four locking holes (611) are respectively adapted to the four locking pins (8) on the next telescopic joint (6) through the conical surface (601) and the inner sliding cylindrical surface (605) of each telescopic joint (6).

7. A flexible drill pipe plug according to claim 6, characterized in that: The shrinking tube (3) is provided with a shrinking cavity (302) inside, and a shrinking neck hole (303) having a diameter smaller than that of the shrinking cavity (302) is provided through the upper part of the shrinking cavity (302). The shrinking cavity (302) forms a sliding fit with the cylindrical boss (603) of the lowest telescopic joint (6). The diameter of the shrinking neck hole (303) is the same as the diameter of the cylindrical surface (602) of the lowest telescopic joint (6). Four shrinking slide bars (304) are evenly provided on the inner wall of the shrinking cavity (302) of the shrinking tube (3). ), four retractable slide bars (304) respectively form a sliding fit with the slide groove (604) of the lowest telescopic joint (6), a retractable stopper (306) adapted to the blocking groove (608) of the lowest telescopic joint (6) is provided inwardly at the bottom of the retractable cavity (302), and four limiting holes (305) respectively adapted to the four locking pins (8) on the lowest telescopic joint (6) are provided through the retractable cavity (302), and the height of the retractable cylinder (3) is equal to the height of the telescopic joint (6).

8. A flexible drill pipe plug according to claim 7, characterized in that: An inner cover cavity (202) is provided in the middle of the top cover (2), a top cover through hole (203) penetrating the inner cover cavity (202) is provided on the lower surface of the top cover (2), four top cover slideways (204) are evenly provided on the inner wall of the inner cover cavity (202), a top locking strip (10) is slidably provided in each of the four top cover slideways (204), a round table (1001) is provided on the top locking strip (10), a top spring (11) is connected between the inner wall of the inner cover cavity (202) and the round table (1001), one end of the top locking strip (10) facing the central axis of the top cover (2) is a limit table (1002), and a top locking arc surface (1003) is provided on the top locking strip (10) and located between the round table (1001) and the limit table (1002); A top locking block (12) is provided at the top of the uppermost telescopic joint (6); the diameter of the top locking block (12) is equal to the diameter of the top cover through hole (203); four top locking grooves (1201) for respectively clamping four top locking strips (10) are evenly provided on the cylindrical surface of the top locking block (12); a locking inclined surface (1202) for driving the limit platform (1002) is provided on the upper part of the top locking block (12); and a through hole (1203) is provided in the top locking block (12) along the axis; A sealing block (13) is provided at the bottom of the inner sliding cylindrical surface (605) of the uppermost telescopic joint (6), a main spring (14) is provided between the sealing block (13) and the upper surface of the inner cover cavity (202) of the top cover (2), and the main spring (14) passes through the inner sliding cylindrical surfaces (605), the neck hole (606) and the through hole (1203) of the top locking block (12) of all telescopic joints (6).

9. A flexible drill pipe plug according to claim 8, characterized in that: The lower part of the socket (4) is a circular inclined surface (401), and four socket slideways (402) are evenly arranged on the cylindrical surface of the socket (4) and located above the circular inclined surface (401). A driving slide bar (15) is slidably arranged in each of the four socket slideways (402), and one end of the driving slide bar (15) is an external driving inclined surface (1501) extending to the socket (4). A limit block (16) is arranged on the upper part of the other end of the driving slide bar (15), and the limit block (16) is located inside the socket (4). A limit spring (17) is connected between the socket (4) and the driving slide bar (15), and a low limit plate (18) is arranged on the upper part of the limit block (16). The lower surface of the low limit plate (18) is The upper surface of the lower limit plate (18) is evenly provided with four limit grooves (19) for clamping the limit block (16); the upper surface of the lower limit plate (18) is connected with a connecting block (20); the upper surface of the connecting block (20) is connected with a high limit plate (21); two side support plates (22) are symmetrically provided on the side of the high limit plate (21); two arc rods (23) are symmetrically provided between the two side support plates (22); side sliding seats (24) are slidably provided on the arc rods (23); the side sliding seats (24) are fixedly provided on the inner wall of the socket (4); the outer side of the arc rods (23) is sleeved with an arc spring (25); the two ends of the arc spring (25) are respectively connected to the side support plates (22) and the side sliding seats (24); A clamping platform (26) is provided at the bottom of the sealing block (13), a clamping hole (2101) for clamping the clamping platform (26) is provided in the middle of the high limit plate (21), and the thickness of the clamping platform (26) is smaller than the height of the connecting block (20).

10. The flexible drill pipe plug according to claim 1, characterized in that: The core body (1) is made of elastic steel wire rope material, a circular hole connected to the core body (1) is provided below the top cover (2), and a circular hole connected to the core body (1) is provided above the shrinking cylinder (3).

Images