Self-adaptive variable-diameter scraper for combined casing

Abstract

A self-adaptive variable-diameter scraper for a combined casing, comprising: an outer pipe; at least one blade assembly, each blade assembly comprising a plurality of blade blocks; an inner sliding sleeve, axially movably arranged inside the outer pipe; an elastic assembly, comprising a plurality of elastic sheets; and a caliper assembly, comprising a plurality of caliper linkage rods, wherein the upper ends of the caliper linkage rods axially movably extend into the outer pipe from the side wall of the outer pipe, and when the caliper linkage rods are squeezed by the borehole wall due to reduction of the borehole wall diameter, the upper ends can axially move upward and push the elastic sheets to pop out and disengage from the inner sliding sleeve, so that the inner sliding sleeve moves downward and drives the blade blocks to radially retract inward. The present device can automatically adjust the scraping diameter range downhole, thereby solving the problem of repeated tripping-in and tripping-out operations required for existing combined casing wellbore cleaning, and can ensure that the scraping force of the blade assembly remains substantially consistent in casings of different diameters.

Description

Combined casing self-adaptive variable-diameter scraper

[0001] The present application claims priority to the Chinese patent application No. 202411310624.3, filed on September 19, 2024, and entitled "Combined casing self-adaptive variable-diameter scraper", the entire contents of which are incorporated herein by reference. TECHNICAL FIELD

[0002] The present disclosure relates to the technical field of oilfield completion operations, and in particular to a combined casing self-adaptive variable-diameter scraper. BACKGROUND

[0003] With the gradual exploration and development of oil and gas resources towards deep layers, the proportion of deep wells, ultra-deep wells and long horizontal wells in major production areas is rapidly increasing, and the long well construction period has become a bottleneck for rapid production of deep natural gas. After drilling or perforating operations, a special casing scraper is needed for wellbore cleaning operations to remove the cement and burrs left on the inner wall of the casing. If these are not removed, it will affect the subsequent tool running, scratch the rubber of the packer, and affect the setting effect. However, as the well depth increases, the well structure becomes more complex, and more and more typical well structures are combined from top to bottom as 7" + 5", 73 / 4" + 5 1 / 2", etc. Two kinds of scrapers corresponding to the casing sizes need to be run in separately, and the casing needs to be cleaned by scraping in each trip, which leads to a long completion period.

[0004] The paper "Variable-diameter pipe scraper structure design and test" introduces a combined casing scraper with a split spring structure, but there is a problem that the scraping force differs greatly in different diameter boreholes. The patent with application No. 202110049934.4 and title "A controllable variable-diameter pipe scraper" proposes a scraper that controls the opening and closing of the scraper by installing a special hydraulic pipeline, but this patent needs to install a hydraulic pipeline independently, which has the problems of high construction difficulty and high operation cost. The patents with application No. 201910247041.3 and title "A variable-diameter pipe scraper" and application No. 202010126785.2 and title "A variable-diameter casing scraper" respectively propose scrapers that gradually open the scraper to adapt to large-diameter casings by hydraulic pressure after the ball is dropped, and scrapers that scrape the small-diameter casing below first, and then extend the scraper to scrape the large-diameter casing above after the ball is dropped.

[0005] After investigation, the variable-diameter scrapers proposed for the problem of multiple trips for cleaning operations of combined casing with large diameter on top and small diameter on the bottom mostly have the problems of complex construction operation, poor adaptability and large scraping force difference, and difficult to guarantee scraping effect, etc. Therefore, there is an urgent need for a more reliable and convenient combined casing variable-diameter scraper. SUMMARY

[0006] The present disclosure aims to provide a combined casing self-adaptive variable-diameter scraper, which can automatically adjust the scraping diameter range downhole, complete the combined casing cleaning operation with one trip of the pipe string, solve the problem of repeated tripping in the existing combined casing wellbore cleaning, and ensure that the scraping force of the scraper assembly is basically consistent in different diameter casings.

[0007] The present disclosure is achieved in this way, and provides a combined casing self-adaptive variable-diameter scraper, comprising:

[0008] an outer pipe;

[0009] at least one group of scraper assemblies, each group of scraper assemblies comprising a plurality of scraper blocks arranged circumferentially and spaced apart on the outer side of the upper portion of the outer pipe and capable of being radially retracted;

[0010] an inner sliding sleeve arranged axially movably inside the outer pipe, and the upper end of the inner sliding sleeve is capable of extending out of the side wall of the outer pipe and being connected with the scraper assembly;

[0011] a resilient assembly comprising a plurality of resilient sheets arranged circumferentially and spaced apart inside the outer pipe, the lower end of each resilient sheet is capable of abutting against a limiting position on the inner wall of the outer pipe, and the upper end is capable of being clamped in the lower end of the inner sliding sleeve to axially limit the inner sliding sleeve;

[0012] a diameter measuring assembly comprising a plurality of diameter measuring connecting rods arranged circumferentially and spaced apart on the outer side of the lower portion of the outer pipe, the upper end of the diameter measuring connecting rod is capable of extending axially movably into the outer pipe from the side wall of the outer pipe; the diameter measuring connecting rod is capable of moving the upper end thereof axially upward under the action of being extruded by the well wall when the well wall is reduced, and pushing each resilient sheet to pop out and disengage from the inner sliding sleeve, so that the inner sliding sleeve moves downward and drives each scraper block to retract radially inward.

[0013] In an optional embodiment of the present disclosure, each diameter measuring connecting rod comprises a lower diameter measuring rod, an upper diameter measuring rod and an axial sliding rod sequentially hinged from bottom to top, the lower end of the lower diameter measuring rod is hinged with the outer pipe, the included angle between the lower diameter measuring rod and the upper diameter measuring rod is obtuse, and the upper end of the axial sliding rod is capable of extending into the outer pipe.

[0014] In an optional embodiment of the present disclosure, a roller is further arranged at the hinged position of the lower diameter measuring rod and the upper diameter measuring rod.

[0015] In an optional embodiment of the present disclosure, a plurality of lower insertion holes are circumferentially arranged on the side wall of the outer pipe, the upper end of the axial sliding rod is capable of passing through the lower insertion hole, and a sealing ring is arranged between the axial sliding rod and the lower insertion hole.

[0016] In an optional embodiment of the present disclosure, a plurality of lower mounting grooves are circumferentially arranged on the outer side wall of the lower portion of the outer pipe, each diameter measuring connecting rod is mounted in the corresponding lower mounting groove, the lower end of the lower diameter measuring rod is hinged with the bottom groove wall of the lower mounting groove, the top groove wall of each lower mounting groove is provided with a lower insertion hole communicating with the inside of the outer pipe, and the upper end of the axial sliding rod is capable of passing through the lower insertion hole.

[0017] In an optional embodiment of the present disclosure, a limiting groove is formed on the inner wall of the outer tube, a clamping groove is formed on the lower outer wall of the inner sleeve, the lower end of the elastic sheet can abut against the bottom groove wall of the limiting groove, and the upper end of the elastic sheet can be clamped in the clamping groove.

[0018] In an optional embodiment of the present disclosure, an upper protruding ring is protruded inwardly from the middle inner wall of the outer tube, a lower protruding ring is protruded outwardly from the outer wall of the inner sleeve, the lower protruding ring is located below the upper protruding ring, a compression spring is sleeved on the outer sleeve of the inner sleeve, and the upper and lower ends of the compression spring can abut against the upper and lower protruding rings, respectively.

[0019] In an optional embodiment of the present disclosure, each group of scraper assemblies further comprises a driving link and at least two parallel driven links above the driving link, the driving link comprises upper and lower driving links hingedly connected, the lower end of the lower driving link is connected to the inner sleeve, the upper end of the upper driving link is hingedly connected to the lower inner wall of the scraper block, the axial direction of the lower driving link is parallel to the axial direction of the outer tube, and the axial direction of the upper driving link is inclined upward from the inside to the outside of the outer tube; the lower end of the driven link is hingedly connected to the upper inner wall of the scraper block, the upper end of the driven link is hingedly connected to the outer tube, and the axial direction of the driven link is inclined downward from the inside to the outside of the outer tube.

[0020] In an optional embodiment of the present disclosure, the upper outer wall of the inner sleeve is formed with a plurality of mounting limiting spaces, and the lower driving link can be limitingly mounted in the corresponding mounting limiting space; an adjusting spring is sleeved on the lower outer side of the lower driving link, a stop portion is formed on the outer wall of the lower driving link, and the upper and lower ends of the adjusting spring can abut against the stop portion and the bottom limiting portion of the mounting limiting space, respectively.

[0021] In an optional embodiment of the present disclosure, the inner sleeve comprises a sleeve body and a plurality of mounting plates extending upward from the upper end of the sleeve body and arranged at intervals in the circumferential direction, each mounting plate is provided with an upper limiting portion and a lower limiting portion spaced apart in the axial direction, the area enclosed by the upper limiting portion, the mounting plate and the lower limiting portion constitutes a mounting limiting space, and the lower limiting portion constitutes a bottom limiting portion; the lower limiting portion is located in the outer tube, and the upper end of the mounting plate extends out of the side wall of the outer tube.

[0022] In an optional embodiment of the present disclosure, a plurality of upper mounting grooves are formed in the upper outer wall of the outer tube at positions corresponding to the plurality of scraper blocks, respectively, the upper end of each driven link is hingedly connected to the upper groove wall of the upper mounting groove, and the bottom groove wall of each upper mounting groove is formed with an upper insertion hole communicating with the inside of the outer tube, the mounting plate and the lower driving link can move through the upper insertion hole.

[0023] In an optional embodiment of the present disclosure, the number of scraper assemblies is two and the two groups of scraper assemblies are arranged at intervals in the vertical direction, and the scraper blocks of the two groups of scraper assemblies are arranged in a staggered manner in the circumferential direction of the outer tube.

[0024] In an optional embodiment of the present disclosure, the lower limiting portion of each mounting plate corresponding to the lowest scraper assembly can abut against the upper protruding ring after the inner sliding sleeve moves downward.

[0025] In an optional embodiment of the present disclosure, a sliding rail extending along the axial direction of the outer tube is protruded on the mounting plate, and a track slot extending along the axial direction of the outer tube and penetrating up and down is provided on the lower driving rod, and the sliding rail is slidably inserted into the track slot.

[0026] In an optional embodiment of the present disclosure, the upper limiting portion on each mounting plate is detachably provided at the top end of the mounting plate.

[0027] In summary, the scraper of the present disclosure, by cooperation of the diameter measuring assembly, the elastic assembly and the inner sliding sleeve, when the scraper is lowered into a small-diameter casing from a large-diameter casing, the diameter measuring assembly can be pushed to open the elastic sheets and the inner sliding sleeve can be moved downward by extrusion of the well wall on the diameter measuring assembly, thereby driving the scraper blocks to automatically contract radially, so as to reduce the overall outer diameter of the scraper; the scraper is a self-adaptive variable-diameter scraper suitable for combined casing with large diameter on top and small diameter on bottom, which can realize automatic adjustment of the scraping diameter range of the scraper in the well by real-time sensing of the wellbore diameter by the diameter measuring assembly, without the need for special hydraulic pipelines or ball pressing operation, and the construction operation is simpler and more adaptable, and the combined casing cleaning operation can be completed with one trip of the pipe string, solving the problem of repeated tripping for cleaning of the combined casing wellbore, saving the tripping operation time and reducing the wellbore preparation period of the completion operation. In addition, the scraper blocks are driven to actively contract radially by the downward movement of the inner sliding sleeve, which can ensure that the scraping force of the scraper assembly in different diameter casings is basically consistent, and the scraping effect is better. BRIEF DESCRIPTION OF DRAWINGS

[0028] The following drawings are only intended to schematically illustrate and explain the present disclosure, and do not limit the scope of the present disclosure. Among them:

[0029] Figure 1 is a structural schematic view of the combined casing self-adaptive variable-diameter scraper provided by the present disclosure.

[0030] Figure 2 is a perspective view of the inner sliding sleeve provided with one group of scraper assemblies by the present disclosure.

[0031] Figure 3 is a perspective view of the inner sliding sleeve provided with two groups of scraper assemblies by the present disclosure.

[0032] Figure 4 is a schematic view of the cooperation of the mounting plate and the upper limiting portion provided by the present disclosure.

[0033] Figure 5 is a schematic view of the driving connecting rod provided by the present disclosure.

[0034] Explanation of reference numerals: 1, outer tube; 11, lower mounting groove; 12, limiting groove; 13, upper protruding ring; 14, upper mounting groove; 2, scraper assembly; 21, scraper block; 22, driving link; 221, upper driving rod; 222, lower driving rod; 2221, stop portion; 223, adjusting spring; 224, track groove; 23, driven rod; 3, inner sliding sleeve; 31, clamping groove; 32, lower protruding ring; 33, compression spring; 34, mounting limiting space; 35, sliding sleeve main body; 351, limiting ring; 36, mounting plate; 361, sliding rail; 37, upper limiting portion; 38, lower limiting portion; 4, elastic sheet; 5, diameter measuring assembly; 51, diameter measuring link; 511, lower diameter measuring rod; 512, upper diameter measuring rod; 513, axial sliding rod; 52, roller; 53, sealing ring. DETAILED DESCRIPTION

[0035] In order to have a clearer understanding of the technical features, objectives and effects of the present disclosure, the specific embodiments of the present disclosure will be described with reference to the drawings.

[0036] As shown in FIGS. 1-5, the present embodiment provides a combined casing self-adaptive variable-diameter scraper, comprising:

[0037] an outer tube 1;

[0038] at least one group of scraper assemblies 2, each group of scraper assemblies 2 comprising a plurality of scraper blocks 21 arranged circumferentially and spaced apart on the outer side of the upper portion of the outer tube 1 and capable of being radially contracted;

[0039] an inner sliding sleeve 3 arranged axially movably inside the outer tube 1, and the upper end of which is capable of extending out of the side wall of the outer tube 1 and being connected with the scraper assembly 2;

[0040] an elastic assembly comprising a plurality of elastic sheets 4 arranged circumferentially and spaced apart inside the outer tube 1, the lower end of each elastic sheet 4 being capable of abutting against the limiting inner wall of the outer tube 1, and the upper end being capable of being clamped to the lower end of the inner sliding sleeve 3 to axially limit the inner sliding sleeve 3;

[0041] a diameter measuring assembly 5 comprising a plurality of diameter measuring links 51 arranged circumferentially and spaced apart on the outer side of the lower portion of the outer tube 1, the upper end of the diameter measuring link 51 being capable of extending axially movably into the outer tube 1 from the side wall of the outer tube 1; the diameter measuring link 51 is capable of moving the upper end thereof axially upward under the action of the well wall being reduced and being extruded by the well wall, and pushing each elastic sheet 4 to pop out and disengage from the inner sliding sleeve 3, so as to move the inner sliding sleeve 3 downward and drive each scraper block 21 to contract radially inward.

[0042] Among them, the scraper can be applied to scrape the inner wall of the combined casing, the combined casing comprising a large-diameter casing and a small-diameter casing connected in sequence, the outer tube 1 is vertically arranged when in use, and the scraper assembly 2, the inner sliding sleeve 3 and the diameter measuring assembly 5 are distributed along the axial direction of the outer tube 1 at the upper portion, the middle portion and the lower portion of the outer tube 1, respectively.

[0043] In the initial state, the inner sleeve 3 cannot move downward in the outer tube 1 due to the presence of the elastic pieces 4 in the elastic assembly, at this time the position of the inner sleeve 3 remains unchanged, and the size of each scraper block 21 in the scraper assembly 2 can match the inner diameter of the large-diameter casing. After the scraper is lowered into the large-diameter casing, the lower part of the caliper assembly 5 can be in contact with the inner wall of the casing to sense the change in the well diameter, and each scraper block 21 in the scraper assembly 2 can perform scraping operation on the inner wall of the large-diameter casing. When the scraper continues to be lowered into the small-diameter casing, the lower part of the caliper assembly 5 will move upward after being pressed by the well wall, pushing the upper end of each caliper link 51 upward and pushing each elastic piece 4 to open, and when all the elastic pieces 4 are opened, the inner sleeve 3 can move downward and drive each scraper block 21 to contract radially inward, reducing the overall outer diameter of the scraper and matching the inner diameter of the small-diameter casing, and then performing scraping operation on the inner wall of the small-diameter casing.

[0044] Thus, in the embodiment, the scraper can make the caliper assembly 5 push each elastic piece 4 to open and the inner sleeve 3 to move downward by the pressing of the well wall on the caliper assembly 5 when the scraper is lowered from the large-diameter casing into the small-diameter casing, and then drive each scraper block 21 to automatically contract radially to reduce the overall outer diameter of the scraper. It is a self-adaptive variable-diameter scraper suitable for combined casing with large diameter on top and small diameter at bottom, which can realize automatic adjustment of scraping diameter range of the scraper in the well by the real-time sensing of the wellbore diameter by the caliper assembly 5, without the need of special hydraulic pipeline or ball pressing operation, and the operation is simpler and more adaptable, and the combined casing cleaning operation can be completed by one trip of the pipe string, solving the problem of repeated tripping for cleaning of the combined casing wellbore, saving the tripping operation time and reducing the wellbore preparation period of the completion operation. In addition, the active radial contraction of each scraper block 21 by the downward movement of the inner sleeve 3 can ensure that the scraping force of the scraper assembly 2 in different diameter casings is basically consistent, and the scraping effect is better.

[0045] In order to facilitate the caliper assembly 5 to sense the size change of the well wall and move upward when the well wall becomes smaller, each caliper link 51 includes a lower caliper link 511, an upper caliper link 512 and an axial sliding link 513 which are sequentially hinged from bottom to top, the lower end of the lower caliper link 511 is hinged to the outer tube 1, the included angle between the lower caliper link 511 and the upper caliper link 512 is obtuse, and the upper end of the axial sliding link 513 can extend into the outer tube 1.

[0046] In the natural state, the lower and upper calipers 511 and 512 maintain an obtuse angle relationship, and the hinged positions of the two calipers can closely adhere to the inner wall of the casing. Generally, a roller 52 is arranged at the hinged position of the lower and upper calipers 511 and 512. The axis of the roller 52 is perpendicular to the plane in which the axes of the two rod bodies lie, and the roller 52 rolls in contact with the well wall, thereby reducing the friction between the roller 52 and the well wall. During the process of lowering the scraper into the well (i.e., the process of gradually lowering the scraper from the wellhead to the casing), the roller 52 is in contact with the well wall and closely adheres to the casing wall in real time, so as to realize real-time sensing of the well diameter. When the scraper enters a small-diameter casing, the well diameter decreases, and the well wall will press the roller 52 inward. The roller 52 pushes the lower and upper calipers 511 and 512 inward, the included angle between the two rod bodies increases, the upper end of the upper caliper 512 moves upward, and the axial sliding rod 513 is pushed to move upward.

[0047] It can be understood that a plurality of lower insertion holes are formed in the side wall of the outer tube 1 in the circumferential direction, and the upper end of the axial sliding rod 513 can pass through the lower insertion hole (not shown in the figure). In order to prevent impurities in the well from entering the scraper and affecting the movement of the caliper assembly 5, a sealing ring 53 is arranged between the axial sliding rod 513 and the lower insertion hole to realize internal and external sealing. For example, the sealing ring 53 can be arranged in the lower insertion hole to realize sealing.

[0048] In order to facilitate processing and installation, a plurality of lower installation grooves 11 are arranged in the lower outer side wall of the outer tube 1 in the circumferential direction at intervals, and each caliper connecting rod 51 is installed in a corresponding lower installation groove 11. The lower end of the lower caliper 511 is hinged to the bottom groove wall of the lower installation groove 11, and the top groove wall of each lower installation groove 11 is provided with a lower insertion hole that communicates with the inside of the outer tube 1. The upper end of the axial sliding rod 513 can pass through the lower insertion hole to extend into the outer tube 1.

[0049] The number of lower installation grooves 11, lower insertion holes, and caliper connecting rods 51 is the same, and is determined according to actual needs. For example, in the embodiment, a total of four caliper connecting rods 51 are arranged around the outer tube 1 at intervals and at an included angle of 90 degrees.

[0050] The elastic sheet 4 described above can be, for example, a spring sheet, which is an elastic member in the form of a long strip with a certain curvature. A limiting groove 12 can be formed in the inner wall of the outer tube 1, and a clamping groove 31 can be formed in the lower outer wall of the inner sliding sleeve 3. The lower end of the elastic sheet 4 can abut against the bottom groove wall of the limiting groove 12, and the upper end of the elastic sheet 4 can be clamped in the clamping groove 31. The limiting groove 12 on the outer tube 1 and the clamping groove 31 on the inner sliding sleeve 3 can both be in the form of an annular groove, or both can include a plurality of grooves arranged at intervals in the circumferential direction. The number of elastic sheets 4 can be the same as the number of grooves arranged at intervals in the circumferential direction. For example, in an alternative embodiment, four elastic sheets 4 can be arranged at intervals around the inner sliding sleeve 3.

[0051] The lower end of the elastic sheet 4 is fixed to the outer tube 1 in the initial state, and the upper end is inclined inward and just fits into the clamping groove 31 of the inner sleeve 3 at the end to prevent the inner sleeve 3 from sliding downward. When the axial sliding rod 513 moves upward and contacts the inwardly inclined surface of the elastic sheet 4, the elastic sheet 4 is pushed outward to pop out, and the upper end of the elastic sheet 4 is disengaged from the clamping groove 31 of the inner sleeve 3.

[0052] Further, the upper convex ring 13 is inwardly convex on the inner wall of the middle part of the outer tube 1, the lower convex ring 32 is outwardly convex on the outer wall of the inner sleeve 3, the lower convex ring 32 is below the upper convex ring 13, the above-mentioned limiting groove 12 is below the upper convex ring 13, and the clamping groove 31 is below the lower convex ring 32; the inner sleeve 3 is provided with a compression spring 33, and the upper and lower ends of the compression spring 33 can abut against the upper convex ring 13 and the lower convex ring 32, respectively.

[0053] The compression spring 33 is in a compressed energy storage state in the initial state (i.e., the state that the upper end of the elastic sheet 4 is clamped on the inner sleeve 3), the lower part of the inner sleeve 3 is supported by the elastic sheet 4 from the clamping groove 31, and the upper part is supported by the upper convex ring 13 of the outer tube 1, and is in a fixed state. When the upper end of each elastic sheet 4 distributed around is disengaged from the clamping groove 31 of the inner sleeve 3, the lower part of the inner sleeve 3 loses the constraint, and the compression spring 33 pushes the inner sleeve 3 to move downward.

[0054] In order to facilitate the radial inward contraction of each scraper block 21 when the inner sleeve 3 moves downward, each scraper assembly 2 further comprises a driving link 22 and at least two parallel driven links 23 above the driving link 22, the driving link 22 comprises an upper driving link 221 and a lower driving link 222 hinged above and below, the lower end of the lower driving link 222 is connected to the inner sleeve 3, the upper end of the upper driving link 221 is hinged to the lower inner wall of the scraper block 21, and the axial direction of the lower driving link 222 is parallel to the axial direction of the outer tube 1, and the axial direction of the upper driving link 221 is inclined upward from the inside to the outside of the outer tube 1; the lower end of the driven link 23 is hinged to the upper inner wall of the scraper block 21, the upper end of the driven link 23 is hinged to the outer tube 1, and the axial direction of the driven link 23 is inclined downward from the inside to the outside of the outer tube 1.

[0055] A plurality of mounting limiting spaces 34 are formed on the upper outer wall of the inner sleeve 3, and the lower driving link 222 can be limitedly mounted in the corresponding mounting limiting space 34; an adjusting spring 223 is sleeved on the lower outer side of the lower driving link 222, a stop portion 2221 is formed on the outer wall of the lower driving link 222, and the upper and lower ends of the adjusting spring 223 can abut against the stop portion 2221 and the bottom limiting portion of the mounting limiting space 34, respectively.

[0056] In the normal scraping operation stage, the overall outer diameter of the scraper should be slightly larger than the inner diameter of the casing to be scraped, so that when the scraper blocks 21 are pressed by the well wall during scraping operation, the lower drive rod 222 can slide along the installation limiting space 34, and the damping is adjusted by the compression spring 223, and at the same time, the spring is initially in a compressed state to provide scraping force for the scraper blocks 21 to contact the inner wall of the casing.

[0057] The adjusting spring 223 is always in a compressed state, and there is a certain gap between the lower end of the lower drive rod 222 and the bottom limiting part of the installation limiting space 34, so that the lower drive rod 222 can have a small up-down floating movement during use, which ensures that the scraper blocks 21 can be tightly attached to the well wall during scraping, and the scraping effect is guaranteed. In addition, since the radial contraction of each scraper block 21 is achieved by driving the inner sleeve 3 to move downward, the adjusting spring 223 will not be subjected to a particularly large pressing force, and the force provided by the adjusting spring 223 to the scraper blocks 21 can be basically the same, which ensures that the scraping force of the scraper assembly 2 in different diameter casings is basically consistent. Each drive link 22 is composed of two rod bodies, which are connected by a hinge connection, and the included angle between the two is obtuse. The lower drive rod 222 is installed horizontally in the installation limiting space 34 and can slide up and down along the long strip-shaped installation limiting space 34. The upper drive rod 221 is connected to the lower part of the scraper block 21 by a hinge connection and is in an inclined state. The lower part of the installation limiting space 34 is provided with an adjusting spring 223, and the end of the lower drive rod 222 is in the spring.

[0058] The upper part of the scraper block 21 is connected to at least two driven rods 23, which are equal in size and length and are in parallel relationship with each other. The driven rod 23 and the scraper block 21 are connected by a hinge connection and are in an inclined state with the inclination direction opposite to that of the upper drive rod 221 (for example, the driven rod 23 and the upper drive rod 221 are arranged in a direction that is counterclockwise and clockwise rotated by a certain angle with respect to the axis of the casing 1, respectively, and the angles of counterclockwise and clockwise rotation can be the same or different). The other end of the driven rod 23 is fixedly connected to the outer pipe 1 by a hinge connection.

[0059] Generally, two driven rods 23 are provided for each scraper assembly 2. When the inner sleeve 3 moves downward, it drives the drive link 22 to move downward, and the drive link 22 applies a downward pulling force to the scraper block 21. Since the scraper block 21 is connected to two parallel driven links by a hinge connection, the scraper block 21 as a whole remains in a parallel state with the outer pipe 1 and moves downward and inward, thereby reducing the overall outer diameter of the scraper, and entering a smaller diameter casing to carry out scraping operation.

[0060] Referring to FIG. 2 and FIG. 3, the inner slide sleeve 3 comprises a slide sleeve body 35 and a plurality of mounting plates 36 extending upward from the upper end of the slide sleeve body 35 and arranged circumferentially at intervals, each mounting plate 36 is provided with an upper limiting part 37 and a lower limiting part 38 arranged at intervals in the axial direction, the area enclosed by the upper limiting part 37, the mounting plate 36 and the lower limiting part 38 constitutes the mounting limiting space 34, and the lower limiting part 38 constitutes the bottom limiting part; the lower limiting part 38 is located in the outer tube 1, and the upper end of the mounting plate 36 protrudes from the side wall of the outer tube 1.

[0061] The downward movement of the inner slide sleeve 3 is limited by the upper protruding ring 13, which can limit the downward movement distance and ensure that the overall outer diameter of the scraper block 21 is slightly larger than the inner diameter of the lower small-diameter sleeve after the scraper block 21 is driven to shrink inward, and the overall outer diameter of the roller 52 is not greater than the maximum overall outer diameter of the scraper block 21 in the open state.

[0062] In order to facilitate processing and installation, a plurality of upper mounting grooves 14 are formed in the upper outer wall of the outer tube 1 corresponding to the positions of the plurality of scraper blocks 21, the upper end of each driven rod 23 is hinged to the upper groove wall of the upper mounting groove 14, and the bottom groove wall of each upper mounting groove 14 is provided with an upper insertion hole communicating with the inside of the outer tube 1, and the mounting plate 36 and the lower driving rod 222 can move through the upper insertion hole. That is, the upper insertion hole can be formed in the bottom groove wall of the upper mounting groove 14, and the position of the upper insertion hole is arranged in the moving direction of the mounting plate 36 and the lower driving rod 222, so as to facilitate the movement of the mounting plate 36 and the lower driving rod 222.

[0063] It can be understood that the number of upper mounting grooves 14 is the same as the number of scraper blocks 21, and when the number of scraper assemblies 2 is at least two, each group of scraper assemblies 2 should be arranged at intervals along the axial direction of the outer tube 1, that is, each group of scraper assemblies 2 is distributed in multiple layers along the axial direction of the outer tube 1; each scraper block 21 of adjacent two groups of scraper assemblies 2 should be arranged at intervals along the circumferential direction of the outer tube 1, the gap between the scraper blocks 21 in the same layer can be used as a fluid channel, and the scraper blocks 21 in adjacent layers are arranged at intervals along the circumferential direction, so that the scraping range of the scraper blocks 21 can cover the circumference of the sleeve when the scraper blocks 21 are scraped upward and downward, and the scraping is more thorough. There should be a group of mounting groove assemblies corresponding to each group of scraper assemblies 2 on the outer wall of the outer tube 1, and each group of mounting groove assemblies comprises a plurality of upper mounting grooves 14 arranged at intervals along the circumferential direction of the outer tube 1.

[0064] The specific number of scraper assemblies 2 and scraper blocks 21 in each group of scraper assemblies 2 can be determined according to needs, and in the embodiment, the number of scraper assemblies 2 can be two and arranged at intervals upward and downward, and each scraper block 21 of the two groups of scraper assemblies 2 is arranged at intervals along the circumferential direction of the outer tube 1, and each group of scraper assemblies 2 can include four scraper blocks 21, which can facilitate processing and ensure that the scraping range covers the circumference of the sleeve.

[0065] In addition, the lower limiting part 38 of each mounting plate 36 corresponding to the lowest group of scraper assemblies 2 can abut against the upper protruding ring 13 after the inner slide sleeve 3 moves downward.

[0066] The number of installation limiting spaces 34 is the same as the number of scraper blocks 21. When the scraper assembly 2 is provided with one group, each installation limiting space 34 on the inner sliding sleeve 3 is provided with one layer, as shown in FIG. 2. When the scraper assembly 2 is provided with at least two groups, referring to FIG. 3, each installation limiting space 34 on the inner sliding sleeve 3 is also arranged in layers. The inner sliding sleeve 3 is provided with a plurality of limiting area groups arranged axially at intervals, and each limiting area group includes a plurality of installation limiting spaces 34 arranged circumferentially at intervals. The lower limiting portions 38 of each installation plate 36 in each limiting area group are located on the same circumference, and the upper limiting portions 37 are located on the same circumference and at the top end of the installation plate 36. The lower limiting portions 38 in the bottom limiting area group are located above the upper protruding ring 13, and the inner sliding sleeve 3 can be moved downward to abut against the upper protruding ring 13 at the lower limiting portions 38.

[0067] For the limiting area group at the bottom, a limiting ring 351 is protruded outward at the top end of the sliding sleeve body 35, and the bottom of the installation plate 36 is connected with the limiting ring 351. The portion of the limiting ring 351 corresponding to each installation plate 36 constitutes the corresponding lower limiting portion 38. For the limiting area groups at the other layers, a lower limiting block is protruded on the installation plate 36 at a position away from the top end by a certain distance, and the lower limiting block constitutes the lower limiting portion 38. The upper limiting portions 37 in each limiting area group are provided at the top end of the installation plate 36, which can be an upper limiting block provided at the top end of the installation plate 36. When the number of scraper assemblies 2 is two, as shown in FIG. 3, each installation plate 36 in the inner sliding sleeve 3 is also divided into two groups. The length of the installation plate 36 in one group is greater than that in the other group, and each installation plate 36 in the two groups is arranged circumferentially at intervals.

[0068] The circumferential outer diameter formed by the initial outward opening of the diameter measuring connecting rod 51 and the roller 52 should not be greater than the maximum circumferential outer diameter of the scraper block 21 in the open state. During the downward movement of the inner sliding sleeve 3, the inner sliding sleeve 3 will be limited by the upper protruding ring 13, limiting the downward movement distance, ensuring that the overall circumferential outer diameter of the scraper block 21 is slightly greater than the inner diameter of the lower small-diameter sleeve after the scraper block 21 is driven to shrink inward, and the circumferential outer diameter formed by each roller 52 is not greater than the maximum circumferential outer diameter of the scraper block 21 in the open state.

[0069] Further, referring to FIG. 4 and FIG. 5, a slide rail 361 extending along the axial direction of the outer tube 1 is protruded on the mounting plate 36, and a track groove 224 extending along the axial direction of the outer tube 1 and penetrating up and down is arranged on the lower driving rod 222, and the slide rail 361 is slidably inserted into the track groove 224. The slide rail 361 is located in the mounting limiting space 34, and the track groove 224 is located on the side of the lower driving rod 222 facing the mounting plate 36. By matching the slide rail 361 and the track groove 224, the movement of the lower driving rod 222 can be guided to ensure smooth operation. The upper limiting part 37 on each mounting plate 36 is detachably arranged at the top end of the mounting plate 36, for example, the upper limiting part 37 and the mounting plate 36 can be connected by screws for easy disassembly and convenient installation of the lower driving rod 222.

[0070] Further, the above-described scraper can be used for scraping a combined casing with large diameter on top and small diameter on bottom, and the self-adaptive variable-diameter working method of the scraper includes the following steps:

[0071] S1, the scraper is lowered into the large-diameter casing, the roller 52 is in contact with the inner wall of the casing to sense the well diameter in real time, the scraper block 21 is kept extruded with the casing wall under the action of the adjusting spring 223, and as the scraper is lowered, the scraper block 21 continuously performs scraping operation on the casing wall.

[0072] S2, after the large-diameter casing scraping is completed, the scraper is continuously lowered, the diameter measuring connecting rod 51 enters the small-diameter casing, the roller 52 is extruded by the well wall, pushes the lower diameter measuring rod 511 and the upper diameter measuring rod 512 inward, and makes the axial sliding rod 513 move upward.

[0073] S3, after the axial sliding rod 513 moves upward and contacts the inclined surface of the inwardly inclined elastic sheet 4, the elastic sheet 4 is pushed outward to pop out, and the upper end of the elastic sheet 4 is separated from the clamping groove 31 of the inner slide sleeve 3.

[0074] S4, after the upper ends of the elastic sheets 4 distributed around are separated from the clamping grooves 31 of the inner slide sleeves 3, the lower part of the inner slide sleeve 3 loses the constraint, and the compression spring 33 pushes the inner slide sleeve 3 to move downward.

[0075] S5, during the downward movement of the inner slide sleeve 3, the driving connecting rod 22 is driven to move downward, the driving connecting rod 22 applies downward and inward pulling force to the scraper block 21, since the scraper block 21 is connected with two parallel driven connecting rods through the hinge, the scraper block 21 moves downward and inward as a whole to keep parallel with the outer tube 1, thereby reducing the overall outer diameter of the scraper, and the scraper can be continuously lowered to enter the small-diameter casing to perform scraping operation.

[0076] In summary, the scraper in the embodiment is designed with the diameter measuring assembly 5 to sense the well diameter in real time. When the tool scrapes the upper large-diameter casing to enter the small-diameter casing, the diameter measuring link 51 is contracted under the constraint of the well wall to trigger the inner sliding sleeve 3 to move downward, the inner sliding sleeve 3 drives the driving link 22 to move downward, and the scraper block 21 is contracted inward, thereby reducing the scraping diameter of the scraper to the diameter range of the lower casing. The scraper can continue to be lowered to perform scraping and cleaning operation on the lower small-diameter casing. The multiple diameter measuring links 51 distributed around the pipe string can only trigger the contraction of the scraper block 21 after being completely compressed (even after all the elastic sheets 4 are opened), which can avoid false triggering when contacting the adherents or sand bridges on the well wall. The scraper is used to perform scraping operation on the combined casing with large diameter above and small diameter below. Without the need for tripping, replacing the tool, and additional ball dropping or pressure operation, the scraper block is self-adaptive to the casing diameter to achieve scraping of the combined casing in one trip of the pipe string.

[0077] The above merely illustrates the specific implementation of the present disclosure, and is not intended to limit the scope of the present disclosure. Any equivalent changes and modifications made by any person skilled in the art without departing from the concept and principle of the present disclosure shall fall within the scope of protection of the present disclosure.

Claims

1. A combination cannula self-adapting variable diameter skimmer, characterized by, It includes: An outer tube; At least one group of scraper assemblies, each group of scraper assemblies including a plurality of scraper blocks radially spaced and arranged on the outer side of the upper part of the outer tube and capable of being radially retracted; An inner sleeve capable of being axially moved and arranged inside the outer tube, and the upper end of the inner sleeve capable of being extended out of the side wall of the outer tube and connected with the scraper assemblies; A resilient assembly including a plurality of resilient pieces circumferentially spaced and arranged inside the outer tube, the lower end of each resilient piece capable of abutting against the limiting position on the inner wall of the outer tube, and the upper end of each resilient piece capable of being clamped in the lower end of the inner sleeve to axially limit the inner sleeve; A diameter measuring assembly including a plurality of diameter measuring connecting rods circumferentially spaced and arranged on the outer side of the lower part of the outer tube, the upper end of each diameter measuring connecting rod capable of being axially moved and extended into the outer tube through the side wall of the outer tube; the diameter measuring connecting rod capable of moving the upper end of the diameter measuring connecting rod upwardly and axially under the action of the well wall being reduced and being extruded by the well wall, and pushing each resilient piece to pop out and disengage from the inner sleeve, so that the inner sleeve moves downwardly and drives each scraper block to retract radially inwardly.

2. The combined casing self-adaptive variable-diameter scraper according to claim 1, wherein Each diameter measuring connecting rod includes a lower diameter measuring rod, an upper diameter measuring rod and an axial sliding rod sequentially hinged from bottom to top, the lower end of the lower diameter measuring rod being hinged with the outer tube, the included angle between the lower diameter measuring rod and the upper diameter measuring rod being obtuse, and the upper end of the axial sliding rod capable of being extended into the outer tube.

3. The combined casing self-adaptive variable-diameter scraper according to claim 2, wherein A roller is further arranged at the hinged position of the lower diameter measuring rod and the upper diameter measuring rod.

4. The combined casing self-adaptive variable-diameter scraper according to claim 2, wherein A plurality of lower insertion holes are circumferentially arranged on the side wall of the outer tube, the upper end of the axial sliding rod capable of passing through the lower insertion hole, and a sealing ring being arranged between the axial sliding rod and the lower insertion hole.

5. The combined casing self-adaptive variable-diameter scraper according to claim 4, wherein A plurality of lower mounting grooves are circumferentially spaced and arranged on the outer side wall of the lower part of the outer tube, each diameter measuring connecting rod being mounted in the corresponding lower mounting groove, the lower end of the lower diameter measuring rod being hinged with the bottom groove wall of the lower mounting groove, the top groove wall of each lower mounting groove being provided with a lower insertion hole communicating with the inside of the outer tube, and the upper end of the axial sliding rod capable of passing through the lower insertion hole.

6. The combined casing self-adaptive variable-diameter scraper according to claim 1, wherein A limiting groove is arranged on the inner wall of the outer tube, and a clamping groove is arranged on the outer wall of the lower part of the inner sleeve, the lower end of the resilient piece capable of abutting against the bottom groove wall of the limiting groove, and the upper end of the resilient piece capable of being clamped in the clamping groove.

7. The combined casing self-adaptive variable-diameter scraper according to claim 1, wherein An upper convex ring is inwardly protruded on the middle inner wall of the outer tube, and a lower convex ring is outwardly protruded on the outer wall of the inner sleeve, the lower convex ring being located below the upper convex ring, a compression spring being arranged on the outer sleeve of the inner sleeve, and the upper and lower ends of the compression spring capable of abutting against the upper convex ring and the lower convex ring respectively.

8. The combined sleeve self-adapting reducing scraper according to claim 7, characterized in that, each of the scraper assemblies further comprises a driving link and at least two parallel driven links above the driving link, the driving link comprises upper and lower driving links hingedly connected, the lower end of the lower driving link is connected with the inner sliding sleeve, the upper end of the upper driving link is hingedly connected with the lower inner wall of the scraper block, the axial direction of the lower driving link is parallel to the axial direction of the outer tube, and the axial direction of the upper driving link is inclined upward from the inside to the outside of the outer tube; the lower end of the driven link is hingedly connected with the upper inner wall of the scraper block, the upper end of the driven link is hingedly connected with the outer tube, and the axial direction of the driven link is inclined downward from the inside to the outside of the outer tube.

9. The combined sleeve self-adapting reducing scraper according to claim 8, characterized in that, the upper outer wall of the inner sliding sleeve is formed with a plurality of installation limiting spaces, and the lower driving link is limitingly installed in the corresponding installation limiting space; an adjusting spring is sleeved on the lower part of the outer wall of the lower driving link, a stop portion is formed on the outer wall of the lower driving link, and the upper and lower ends of the adjusting spring can be abutted against the stop portion and the bottom limiting portion of the installation limiting space, respectively.

10. The combined sleeve self-adapting reducing scraper according to claim 9, characterized in that, the inner sliding sleeve comprises a sliding sleeve body and a plurality of installation plates extending upward from the upper end of the sliding sleeve body and arranged circumferentially at intervals, each of the installation plates is provided with an upper limiting portion and a lower limiting portion spaced apart along the axial direction, the upper limiting portion, the installation plate and the lower limiting portion enclose an area constituting the installation limiting space, and the lower limiting portion constitutes the bottom limiting portion; the lower limiting portion is located in the outer tube, and the upper end of the installation plate protrudes from the side wall of the outer tube.

11. The combined sleeve self-adapting reducing scraper according to claim 10, characterized in that, a plurality of upper installation grooves are formed in the upper outer wall of the outer tube at positions corresponding to the plurality of scraper blocks, the upper end of each of the driven links is hingedly connected with the upper groove wall of the upper installation groove, and the bottom groove wall of each of the upper installation grooves is formed with an upper insertion hole communicating with the inside of the outer tube, and the installation plate and the lower driving link can move through the upper insertion hole.

12. The combined sleeve self-adapting reducing scraper according to claim 10, characterized in that, the number of the scraper assemblies is two and the two scraper assemblies are arranged at intervals in the upper and lower directions, and the scraper blocks of the two scraper assemblies are arranged in a staggered manner in the circumferential direction of the outer tube.

13. The combined sleeve self-adapting reducing scraper according to claim 12, characterized in that, the lower limiting portion of each of the installation plates corresponding to the scraper assembly of the lowest layer can abut against the upper convex ring after the inner sliding sleeve moves downward.

14. The combined sleeve self-adapting reducing scraper according to claim 10, characterized in that, a sliding rail extending along the axial direction of the outer tube is convexly formed on the installation plate, a track groove extending along the axial direction of the outer tube and penetrating through the upper and lower portions is formed on the lower driving link, and the sliding rail is slidably inserted into the track groove.

15. The combination sleeve-adapter variable diameter skimmer of claim 14, wherein, The upper limit portion on each of the mounting plates is detachably provided at the top end of the mounting plate.

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