CN116906018A - Old well drags fracturing clamping distance adjustable combination tool - Google Patents

Abstract

The application relates to a combination tool with adjustable clamping distance for dragging fracturing of an old well, which aims to solve the technical problems that the clamping distance can not be adjusted in the fracturing construction process of the old well, and the double-clamping double-sealing operation of the upper end and the lower end of a fracturing working section can not be realized. The tool comprises a bidirectional hydraulic slip, a hydraulic internal pressurizing packer with an expansion joint, a track type bottom sealing packer and a centralizing positioner which are sequentially connected in series; the hydraulic internal pressurizing packer with the telescopic joint comprises a hydraulic packing assembly and a telescopic assembly consisting of a cylinder outer tube and a telescopic piston tube; the hydraulic packing assembly comprises a second central tube and an outer tube, a second piston is arranged between the outer tube of the cylinder barrel and the telescopic piston tube, and the second piston is in sliding fit with the inner cavity of the outer tube of the cylinder barrel; the lower end of the cylinder barrel outer tube is provided with a guide sleeve, and the second piston is abutted with the guide sleeve when sliding downwards to the maximum distance; the lower extreme of cylinder outer tube is provided with a plurality of pressure release slots that extend along the axial and link up the cylinder outer tube.

Description

Old well drags fracturing clamping distance adjustable combination tool

Technical Field

The application relates to an oil well dragging fracturing device, in particular to an adjustable combination tool for a dragging fracturing clamping distance of an old well.

Background

In the process of carrying out fracturing construction on an old well in an oil field, because perforation sections with different perforation lengths are arranged in the old well, the tool string provided for achieving the multi-layer dragging fracturing construction requirement of one-time pipe column is required to meet the upper sealing clamp and the lower sealing clamp, the sealing clamp distance is adjustable, and the existing oil well dragging fracturing device cannot realize.

Disclosure of Invention

The application aims to solve the technical problems that the sealing clamping moment can not be adjusted in the old well fracturing construction process and the double-clamping double-sealing operation of the upper end and the lower end of a fracturing working section can not be realized, and provides an old well dragging fracturing clamping moment adjustable combination tool.

The technical scheme of the application is as follows:

the utility model provides an old well drags fracturing clamping distance adjustable combination tool which characterized in that: the hydraulic pressure type hydraulic pressure well packer comprises a bidirectional hydraulic slip, a hydraulic pressure type internal pressurizing packer with an expansion joint, a track type bottom sealing packer and a centralizing positioner which are sequentially connected in series from top to bottom;

the bidirectional hydraulic slips are used for being clamped with the upper part of the perforating section;

the hydraulic internal pressurizing packer with the telescopic joint comprises a hydraulic packing assembly and a telescopic assembly connected below the hydraulic packing assembly;

the hydraulic packing assembly comprises a second central tube and an outer barrel, and is used for sealing the upper part of the oil well fracturing section;

the telescopic assembly comprises a cylinder outer tube and a telescopic piston tube arranged in the cylinder outer tube;

the cylinder barrel outer tube of the telescopic assembly is fixed with the lower end of the outer cylinder;

the top end of the telescopic piston tube is fixedly provided with a second piston which is in sliding fit with the side wall of the inner cavity of the outer tube of the cylinder barrel;

the inner side surface of the lower end of the cylinder barrel outer tube is provided with a guide sleeve, the telescopic piston tube is in sliding fit with the inner side wall of the guide sleeve, and the second piston can be abutted with the guide sleeve when sliding along with the telescopic piston tube to the maximum distance;

the lower end of the cylinder outer tube is provided with a plurality of pressure relief slots extending along the axial direction, the pressure relief slots are positioned at the position of the cylinder outer tube close to the guide sleeve, and the pressure relief slots penetrate through the cylinder outer tube along the radial direction;

the second central tube is communicated with the telescopic piston tube;

the lower end of the telescopic piston tube is provided with a thread for connecting with a joint section of the track type bottom sealing packer;

the bidirectional hydraulic slip is provided with a first central pipe; the upper end of the second central tube of the hydraulic packing assembly is connected with the first central tube;

the centralizing locator is used for locating the tool string when the tool string is lowered and ensuring that the tool string is positioned in the center of the casing.

Further, the width of the pressure relief slit is smaller than the particle diameter of the fracturing sand or ceramsite in the oil well.

Prevent that fracturing sand or haydite that contains in the oil of gathering from getting into between flexible piston tube and the cylinder outer tube, influence the normal use of flexible piston tube.

Further, the hydraulic packing assembly further comprises a first sealing rubber sleeve and a first piston which are arranged outside the second central tube;

the first sealing rubber sleeve is arranged between the second upper joint and the outer cylinder, the upper end of the first piston extends out of the outer cylinder and is in butt joint with the first sealing rubber sleeve, and the lower end of the first piston extends into the space between the outer cylinder and the second central tube.

Further, the hydraulic internal pressurizing packer with the expansion joint further comprises a throttling assembly arranged between the hydraulic packing assembly and the expansion assembly, the throttling assembly comprises a throttling sleeve, a magnetic seat and a throttling mouth, the magnetic seat is arranged on the inner side of the lower part of the throttling sleeve and magnetically attracted with the second piston, the throttling mouth is arranged on the inner side of the magnetic seat, the throttling mouth is provided with a throttling hole, the diameter of the radial section of the throttling hole is smaller than that of the radial section of the second central pipe, and the throttling hole is communicated with the second central pipe and the expansion piston pipe;

the throttling sleeve is arranged between the outer cylinder and the outer cylinder tube; the upper section of the throttling sleeve extends between the outer cylinder and the second central tube, the lower section of the throttling sleeve extends between the outer cylinder tube and the magnetic seat, and the middle section of the throttling sleeve protrudes outwards and is abutted with the outer cylinder tube and the outer cylinder tube;

the throttling sleeve is provided with a fourth flow passage; the fourth flow passage is arranged at the upper section of the throttling sleeve, extends along the axial direction of the throttling sleeve and penetrates through the throttling sleeve upwards; the end part of the upper section of the throttling sleeve is provided with a gap with the lower end of the first piston, and the gap is communicated with the fourth flow passage;

a throttling sleeve is arranged at the lower part of the second central tube, a plurality of third flow passages are arranged on the side wall of the throttling sleeve, and the third flow passages radially penetrate through the throttling sleeve; a second annular groove is arranged between the throttling sleeve and the middle section of the throttling sleeve, and the second annular groove is communicated with the third flow passage and the fourth flow passage.

Further, the bidirectional hydraulic slip comprises a first upper joint, a first central tube, a plurality of bidirectional slip components arranged outside the first central tube, and a hydraulic driving component and a first lower joint which are symmetrically arranged at the upper end and the lower end of the bidirectional slip components;

the plurality of bi-directional slip assemblies are uniformly distributed along the central axis of the first central tube;

the hydraulic driving assembly comprises a pressing sleeve, a first connecting sleeve, a supporting ring, a second connecting sleeve and a taper sleeve;

one end of the pressing sleeve and one end of the first connecting sleeve of one hydraulic driving assembly are connected with the first upper joint; one end of the pressing sleeve and one end of the first connecting sleeve of the other hydraulic driving assembly are connected with the first lower joint; a gap is formed between the other end of the first connecting sleeve and the taper sleeve;

the other end of the taper sleeve is provided with an outer conical surface matched with the two-way slip assembly; the first connecting sleeve and the second connecting sleeve are axially connected in series;

the middle part of the first connecting sleeve is connected with the supporting ring in a sealing way, and a first runner which extends along the axial direction of the supporting ring and penetrates through the side wall of the supporting ring in the radial direction is arranged on the side wall of the supporting ring;

the inner side of the first connecting sleeve is provided with an annular cavity and a second flow passage which penetrates through the first connecting sleeve along the axial direction and towards the direction close to the bidirectional slip assembly, the first flow passage, the annular cavity and the second flow passage form a first hydraulic passage, and the first hydraulic passage is used for driving the taper sleeve to compress the bidirectional slip assembly under the action of high-pressure liquid to realize clamping.

Further, the track type bottom sealing packer comprises joint sections and a center rod, wherein the joint sections are sequentially connected in series from top to bottom, and the center rod is connected below the joint sections; the device also comprises a main sealing rubber sleeve, a conical body, a slip assembly and a centralizing guide body assembly which are sequentially sleeved on the outer side of the central rod from top to bottom;

the joint section comprises an upper connecting section used for being connected with the oil pipe, a lower connecting section connected with the central rod and a pressure guiding sand blasting assembly arranged between the upper connecting section and the lower connecting section;

the pressure guiding sand blasting assembly comprises a plurality of guiding sand outlets uniformly distributed along the circumferential direction;

the centralizing guide body assembly comprises a centralizing body main body, wherein the centralizing body main body is provided with a mounting groove, a friction body used for being in friction fit with the sleeve is arranged in the mounting groove, and the lower end of the centralizing guide body assembly is provided with a guide pin protruding inwards;

the outer surface of the lower section of the central rod is axially provided with a guide rail groove; the guide rail groove comprises a long guide rail groove and a short guide rail groove which extend along the axial direction, and a reversing guide rail groove which is connected with the lower end of the long guide rail groove and the lower end of the short guide rail groove; the long guide rail groove and the short guide rail groove are arranged at intervals along the circumferential direction;

the guide pin is matched with the guide rail groove.

Further, the slip assembly comprises a plurality of slip assemblies, each slip assembly comprises a second slip bowl, a plurality of second slip teeth and a plurality of second slip teeth retraction springs, the upper ends of the second slip teeth extend out of the upper ends of the second slip bowl, and the lower ends of the second slip teeth are connected in the second slip bowl through the second slip teeth retraction springs;

the second slip bowl is connected with the centralizer body.

Further, the cone comprises a cone cap surrounding the central rod and a cone connected below the cone cap; a first mounting cavity is formed among the cone cap, the cone and the central rod;

the central rod is provided with an annular bulge which is arranged in the first mounting cavity;

when the guide pin is matched with the top end of the short guide rail groove, a gap exists between the annular bulge and the inner surface of the lower side of the first mounting cavity;

alternatively, when the guide pin engages the top end of the long rail groove, the annular projection presses down on the push cone such that the conical surface of the cone is interposed between the slip bowl and the center rod.

Further, the righting positioner comprises a guide righting assembly and a plurality of positioning assemblies which are fixedly connected;

the guide righting assembly comprises a righting body, a connecting groove arranged on the righting body and a plurality of lower limit grooves arranged in the connecting groove;

the positioning assembly comprises a positioning body, a limiting groove arranged on the positioning body and an upper limiting groove arranged corresponding to the lower limiting groove;

the cavity formed by the lower limit groove and the upper limit groove is internally provided with a compression spring, and an elastic piece is arranged between the limit groove and the connecting groove and used for supporting the positioning body and enabling the positioning body to float along the radial direction.

Further, the positioning body comprises a positioning protrusion, and a first guide section and a second guide section which are arranged on two sides of the positioning protrusion, wherein the end face of the positioning protrusion is an arc surface.

The application has the beneficial effects that:

1. the hydraulic internal pressurizing packer with the expansion joint is adjustable in sealing distance between the hydraulic internal pressurizing packer with the expansion joint and the track type bottom sealing packer through the expansion assembly, has stronger practicability compared with the traditional mode of connecting a fixed-length pipeline, is suitable for new well perforation fracturing construction, and is also suitable for old well fracturing production increasing construction with different perforation lengths in the existing multilayer perforation sections.

2. The design of the telescopic component can effectively reduce the whole length of the whole tool string and ensure smooth well descending.

3. Through setting up the pressure guiding sand blasting subassembly at the upper end joint section of track formula bottom sealing packer, need not to assemble in addition and lead the corresponding play sand function that the pressure guiding sand blaster just had, can shorten the length of oil well fracturing tool string, facilitate the use. In addition, the main sealing rubber sleeve, the cone, the slip body assembly and the centralizing guide body assembly are sequentially sleeved outside the central rod, long guide rail grooves and short guide rail grooves are alternately formed in the lower end surface of the central rod at intervals, and sealing and clamping between the bottom sealing packer and the oil pipe are realized through matching of guide pins and the guide rail grooves.

4. The bidirectional hydraulic slips are driven by the two sets of hydraulic driving assemblies to outwards expand, so that bidirectional reliable clamping can be realized, and the slips can be prevented from being damaged due to uneven stress on two sides of the bidirectional slips.

5. The centralizing positioner combines the conventional guiding centralizing device and the conventional centralizing device into a whole, so that the composite centralizing positioner with comprehensive functions of guiding, rigid centralizing, elastic centralizing and positioning sensing is formed, the structure is compact, the functions are complete, the centralizing effect is good, the length of the whole tool string is reduced, and the tool string is more beneficial to logging in and lifting.

Drawings

FIG. 1 is a schematic diagram of an embodiment of the present application;

FIG. 2 is a schematic diagram of a two-way hydraulic slip according to an embodiment of the present application;

FIG. 3 is a schematic view of a hydraulic internal booster packer with a telescopic joint in an embodiment of the application in a retracted state;

FIG. 4 is an enlarged view of a portion of FIG. 3 at A;

FIG. 5 is a partial enlarged view at B in FIG. 3;

FIG. 6 is a schematic view of a hydraulic internal booster packer with an expansion joint in an embodiment of the application in an extended configuration;

FIG. 7 is a schematic diagram of a track-type bottom-seal packer (stuck-released state) according to an embodiment of the application;

FIG. 8 is an enlarged view of a portion of the portion I of FIG. 7;

FIG. 9 is an enlarged view of a portion of the portion II of FIG. 7;

FIG. 10 is an enlarged view of a portion of III of FIG. 7;

FIG. 11 is a schematic diagram of a composite track type bottom seal packer (clamped state) according to an embodiment of the application;

FIG. 12 is a schematic diagram of a centralizer in accordance with an embodiment of the application;

FIG. 13 is a front view of a righting assembly of a righting locator in accordance with an embodiment of the present application;

FIG. 14 is a front view of a positioning assembly of a centralizer in accordance with an embodiment of the application.

The reference numerals are as follows: 1-two-way hydraulic slips, 11-first upper joint, 12-hydraulic drive assembly, 121-compression sleeve, 122-first connecting sleeve, 123-supporting ring, 124-second connecting sleeve, 125-taper sleeve, 13-first central tube, 14-two-way slip assembly, 141-first slip bowl, 142-spring, 143-first slip tooth, 144-bow spring, 15-first lower joint;

2-a hydraulic internal pressurizing packer with an expansion joint, 21-a second upper joint, 22-a first sealing rubber sleeve, 221-a spring steel wire, 222-a first annular groove, 23-a first piston, 24-an outer cylinder, 25-a second central tube, 26-a magnetic seat, 27-a throttle nozzle, 28-a second piston, 29-a telescopic piston tube, 210-a cylinder outer tube, 2101-a pressure relief slit, 211-a guide sleeve, 212-a second hydraulic channel, 213-a throttle sleeve, 241-an upper section of the outer cylinder, 242-a middle section of the outer cylinder, 243-a lower section of the outer cylinder, 2121-a fourth flow channel, 2122-a second annular groove and 2123-a third flow channel;

3-track bottom seal packer, 31-joint section, 32-center rod, 33-main seal gum cover, 35-cone cap, 36-cone, 37-slip assembly, 38-centralizing guide assembly, 310-cemented carbide layer, 311-tubing box, 312-pilot sand outlet, 314-first installation cavity, 315-shear pin, 321-blind hole, 322-long guideway slot, 323-short guideway slot, 324-reversing guideway slot, 325-buffer slot, 326-annular protrusion, 331-circumferential groove, 332-round spring, 371-second slip socket, 372-second slip tooth, 373-second slip tooth retraction spring, 381-centralizing body, 382-supporting elastomer, 383-friction body, 384-ring sleeve, 385-guide ring, 386-guide pin, 3811-installation slot, 3851-through hole;

4-righting locator, 41-righting body, 42-platen, 43-locating body, 44-leaf spring, 45-compression spring, 46-bolt, 411-fourth upper joint, 412-intermediate, 413-righting body, 414-guide head, 4121-connecting slot, 4122-lower limit groove, 4131-righting boss, 431-limit groove, 432-upper limit groove, 433-locating boss, 434-mounting rim, 435-first guide section, 436-first guide section.

Detailed Description

In the embodiment, the front end of the old well dragging fracturing clamping distance adjustable combined tool string along the falling direction of the oil well is defined as lower, and the rear end of the old well dragging fracturing clamping distance adjustable combined tool string is defined as upper in actual use.

Referring to fig. 1, an embodiment of the present application provides a combination tool with adjustable trailing fracturing truck spacing for old wells, the combination tool comprising: the two-way hydraulic slip 1, the hydraulic internal pressurizing packer 2 with expansion joint, the track type bottom sealing packer 3 and the centralizing locator 4 are sequentially connected in series from top to bottom along the axial direction. The bidirectional hydraulic slips 1 are used for clamping the upper part of a casing, the track type bottom sealing packer 3 is used for clamping the lower part of a casing and sealing and fracturing construction section and performing perforation and fracturing, and the righting locator 4 is used for improving the locating accuracy of the tool string and ensuring that the tool string is positioned in the center of the casing when the tool string is lowered.

Referring to fig. 2, the two-way hydraulic slip 1 includes a first upper joint 11, a first lower joint 15, a first center tube 13, a two-way slip assembly 14 disposed outside of the two-way hydraulic slip first center tube, and two hydraulic drive assemblies 12. The outside of the first central tube 13 is sleeved with a two-way slip assembly 14 and a hydraulic driving assembly 12 symmetrically arranged at the upper end and the lower end of the two-way slip assembly, the upper end of the hydraulic driving assembly 12 at the upper end of the two-way slip assembly 14 is connected with a first upper joint 11, and the lower end of the other hydraulic driving assembly 12 is connected with a first lower joint 15. The two hydraulic drive assemblies 12 can drive the bi-directional slip assemblies 14 to expand outwardly simultaneously, thereby realizing reliable clamping of the slips and preventing damage to the slips caused by uneven stress on both sides of the slips.

The hydraulic drive assembly 12 includes a compression sleeve 121, a first connection sleeve 122, a support ring 123, a cone sleeve 125, and a second connection sleeve 124. Taking the hydraulic driving assembly 12 located at the upper end of the two-way slip assembly 14 as an example, the upper end of the first connecting sleeve 122 is specifically configured to be connected with the first upper joint 11; the first connecting sleeve 122 and the second connecting sleeve 124 are connected in series along the axial direction, the lower part of the first connecting sleeve 122 and the upper part of the taper sleeve 125 are sleeved in the second connecting sleeve 124, a gap is reserved between the lower end of the first connecting sleeve 122 and the upper end of the taper sleeve 125, an outer conical surface is arranged at the lower end of the taper sleeve 125, inner conical surfaces matched with the outer conical surface are arranged at the two ends of the two-way slip assembly 14, and the taper sleeve 125 can slide between the second connecting sleeve 124 and the first central tube 13 along the axial direction.

The first connecting sleeve 122 is internally provided with an annular cavity and a second flow passage which extends along the axial direction in the annular cavity and is close to the lower end of the two-way slip assembly 14 and penetrates through the lower end of the first connecting sleeve 122, the first connecting sleeve 122 is internally and hermetically connected with a supporting ring 123, the supporting ring 123 is tightly pressed in the first connecting sleeve 122 through a pressing sleeve 121, and the pressing sleeve 121 is connected in the first connecting sleeve 122 through threads; the side wall of the supporting ring 123 is provided with a first flow passage, the first flow passage is communicated with the inner cavity of the supporting ring 123 and the annular cavity of the first connecting sleeve 122, the first flow passage, the annular cavity and the second flow passage form a first hydraulic passage, the first hydraulic passage is communicated with a gap between the first connecting sleeve 122 and the taper sleeve 125, and the first hydraulic passage is used for driving the taper sleeve 125 to compress the bidirectional slip assembly 14 under the action of high-pressure liquid to realize clamping. Specifically, the first flow channel is a slit disposed on a sidewall of the support ring 123, and the slit extends along an axial direction of the support ring 123 and penetrates through the sidewall of the support ring 123 in a radial direction.

The bi-directional slip assembly 14 includes a first slip bowl 141 and a plurality of first slip teeth 143, the first slip bowl 141 being positioned between the two second coupling sleeves 124, the first slip bowl 141 having a first mounting groove therein, the first slip teeth 143 being positioned in the first mounting groove; the two outer ends of the first slip seat 141 are respectively provided with an inner conical surface, and the two inner conical surfaces are respectively abutted with the outer conical surfaces of the two conical sleeves 125.

An elastic member is provided between the first slip bowl 141 and the first slip bowl 143, and is capable of providing a contractive force to the first slip bowl 143. Specifically, the elastic component is the bow spring 144, is equipped with the second mounting groove on the first slips tooth 143, and the both ends of bow spring 144 are leaned on with the inner wall of first slips seat 141, and the middle part of bow spring 144 is leaned on with the tank bottom of second mounting groove, utilizes the elastic action of bow spring 144 can make first slips tooth 143 and sleeve pipe release joint.

A reset member is provided between the first slip bowl 141 and the cone sleeve 125 at both ends, the reset member being capable of providing a force to the cone sleeve 125 to move in a direction away from the first slip bowl 141. Specifically, the restoring member is a spring 142, a spring seat is disposed in the first slip seat 141, a spring accommodating groove extending along an axial direction is disposed in the cone sleeve 125, one end of the spring 142 abuts against the spring seat, and the other end of the spring 142 extends into the spring accommodating groove. The bow spring 144 cooperates with the spring 142 to release the first slip element 143 from engagement with the sleeve to effect a reset of the first slip element 143.

Referring to fig. 3-6, a hydraulic internal boost packer with a telescopic joint includes a hydraulic packer assembly, a throttle assembly, and a telescopic assembly.

The hydraulic packing assembly is used for sealing the annular space of a sleeve at the upper part of the oil well fracturing section and comprises a second upper joint 21, a first sealing rubber sleeve 22, a first piston 23, a second central tube 25, an outer cylinder 24 and a throttling sleeve 213; the upper end of the second upper joint 21 is provided with an oil pipe box, the lower end of the second upper joint 21 is connected with a second central pipe 25, and the outside of the second central pipe 25 is sleeved with a first sealing rubber sleeve 22, a first piston 23 and an outer cylinder 24 in sequence from top to bottom; the first sealing rubber sleeve 22 is arranged between the second upper joint 21 and the outer cylinder 24, the upper end of the first piston 23 extends out of the outer cylinder 24 and is in butt joint with the first sealing rubber sleeve 22, and the lower end of the first piston 23 extends into the space between the outer cylinder 24 and the second central tube 25;

the throttle sleeve 213 is arranged between the outer cylinder 24 and the outer cylinder tube 210, the upper section of the throttle sleeve 213 extends between the outer cylinder 24 and the second central tube 25, and the middle section of the throttle sleeve 213 is abutted with the outer cylinder 24 and the outer cylinder tube 210;

the throttle sleeve 213 has a fourth flow passage 2121; the fourth flow passage 2121 is provided at an upper section of the throttle sleeve 213 extending between the outer tube 24 and the second center tube 25, and extends axially along the throttle sleeve 213 and axially penetrates the throttle sleeve 213; the end of the upper section of the throttling sleeve is provided with a gap with the lower end of the first piston, and the gap is communicated with the fourth flow passage.

A third flow passage 2123 is arranged at the lower part of the second central tube 25, and the third flow passage 2123 radially penetrates through the second central tube 25, extends along the axial direction of the second central tube 25 and is uniformly distributed circumferentially; a second ring groove 2122 is provided between the second center tube 25 and the throttle sleeve 213, and the second ring groove 2122 communicates with the third flow passage 2123. It will be appreciated that a throttling sleeve may be embedded in the lower portion of the second central tube 25, and a plurality of third flow passages 2123 may be provided on the throttling sleeve, the third flow passages 2123 penetrating the throttling sleeve in the radial direction, and a second ring groove 2122 may be provided between the throttling sleeve and the throttling sleeve 213; the provision of the throttling sleeve facilitates replacement of the throttling sleeve without the need for replacement and maintenance of the entire second center tube 25 in the event of damage to the third flow passage 2123 caused by the action of the high-pressure liquid during use.

The fourth flow passage 2121, the second ring groove 2122 and the plurality of third flow passages 2123 form a second hydraulic passage 212 which is communicated with each other, and the high-pressure liquid in the second central tube 25 applies thrust to the first piston 23 through the second hydraulic passage 212 to drive the first sealing rubber sleeve 22 to compress so that the first sealing rubber sleeve 22 elastically changes and protrudes outwards to be closely connected with the sleeve to realize sealing.

The spring steel wires 221 are arranged at the two ends of the first sealing rubber sleeve 22, and the spring steel wires 221 can protect the deformation condition of the two ends of the first sealing rubber sleeve 22 in a compressed state and avoid failure caused by the breakage of the two ends of the first sealing rubber sleeve 22; a plurality of first ring grooves 222 are provided on the outer cylindrical surface and the inner wall surface of the first packing sleeve 22.

The throttling assembly comprises a magnetic seat 26 and a throttling mouth 27, the magnetic seat 26 is connected to the inner side of the lower section of the throttling sleeve 213, the throttling mouth 27 is arranged close to the inner side surface of the magnetic seat 26, the throttling mouth 27 is provided with a throttling hole, the area of the radial section of the throttling hole is smaller than that of the radial section of the second central tube 25, and a pressure difference is formed at the upper end and the lower end of the throttling hole; to prevent the throttle 27 from being damaged by erosion, the throttle 27 is made of an erosion resistant material.

The telescopic assembly comprises a cylinder outer tube 210, a telescopic piston tube 29, a second piston 28 and a guide sleeve 211, wherein the upper end of the cylinder outer tube 210 is connected to the outer side of the lower section of a throttle sleeve 213 and is abutted to the middle section of the throttle sleeve 213, the guide sleeve 211 is connected to the inner side of the lower end, the telescopic piston tube 29 is arranged in the cylinder outer tube 210, the upper end of the telescopic piston tube 29 is fixedly connected with the second piston 28 through threads, and the second piston 28 is in sliding fit with the inner cavity of the cylinder outer tube 210.

The cylinder barrel outer tube 210 is internally and slidably connected with a telescopic piston tube 29 through a second piston 28, the outer diameter of the second piston 28 is matched with the inner diameter of the cylinder barrel outer tube 210, the telescopic piston tube 29 is in sealing fit with a guide sleeve 211 on the inner side of the cylinder barrel outer tube 210, and when the telescopic piston tube 29 moves up and down, the second piston 28 can axially slide along the cylinder barrel outer tube 210; in the extended state during operation, the lower end of the telescopic piston tube 29 extends out of the cylinder tube 210, and an oil tube pin is machined at the lower end of the telescopic piston tube 29.

The outer barrel 24 comprises an outer barrel upper section 241, an outer barrel middle section 242 and an outer barrel lower section 243, and the inner diameter of the outer barrel upper section 241 is larger than that of the outer barrel middle section 242; the first piston 23 is positioned in the upper section 241 of the outer cylinder, and the upper end of the first piston 23 extends out of the upper end of the upper section 241 of the outer cylinder and then is abutted against the sealing rubber cylinder 222; the middle section 242 of the outer cylinder is provided with a gap with the first piston 23, and the gap is communicated with the hydraulic channel; the inner side of the outer cylinder lower section 243 is connected to the throttle sleeve 213.

The lower extreme of cylinder outer tube 210 passes through uide bushing 211 and flexible piston tube 29 sealing connection, is equipped with along the axial extension and along a plurality of pressure release slots 2101 that link up radially on the lateral wall of cylinder outer tube 210, and pressure release slots 2101 set up in the position that cylinder outer tube 210 is close to uide bushing 211, and along the circumference equipartition of cylinder outer tube 210.

Referring to fig. 7-11, the track-type bottom-seal packer 3 comprises a joint section 31 with a pressure-guiding sand blasting assembly, a main sealing rubber sleeve 33, a central rod 32, a cone, a slip assembly 37 and a centralizing guide body assembly 38 which are sequentially connected in series from top to bottom.

The upper part of the joint section 31 with the pressure guiding sand blasting assembly is connected with an oil pipe through an oil pipe box 311, the lower part is connected with a central rod 32, the middle part is provided with a plurality of pressure guiding sand blasting assemblies along the belt, each pressure guiding sand blasting assembly is provided with a plurality of guiding sand outlets 312 uniformly distributed along the circumferential direction, and the periphery of each guiding sand outlet 312 is sprayed with a high wear-resistant alloy material to form a hard alloy layer 310 so as to improve the service life of the sand blasting opening and meet the multi-layer large-displacement fracturing requirement. In this embodiment, the number of the guiding sand outlets 312 is four, and in other embodiments, the number of the guiding sand outlets 312 may be three or five, and the number of the guiding sand outlets 312 may be set according to the actual working conditions.

The main sealing rubber sleeve 33 is a single compound rubber sleeve, and the periphery and the inner hole of the main sealing rubber sleeve 33 are respectively provided with three circumferential grooves 331 which are circumferentially arranged, so that the two ends of the outer ring of the main sealing rubber sleeve 33 are bonded with the round springs 332 in a compression deformation manner of the main sealing rubber sleeve 33, and the function of the main sealing rubber sleeve is to protect the deformation conditions of the two ends of the compressed main sealing rubber sleeve 33 and avoid the breakage and failure of the two ends of the main sealing rubber sleeve 33.

The slip assembly 37 includes a second slip bowl 371 and a plurality of second slip teeth 372 and a plurality of second slip teeth retraction springs 373, the upper ends of the second slip teeth 372 extending beyond the upper ends of the second slip bowl 371, the lower ends of the slip teeth 372 being resiliently connected within the second slip bowl 371.

The righting guide body assembly 38 includes a righting body 381, a friction body 383, a supporting elastomer 382, a collar 384, a guide ring 385 disposed within the collar 384, and a guide pin 386. The guide ring 385 is provided with a through hole 3851, and the guide pin 386 passes through the through hole 3851 and then extends into a specific guide rail groove of the central rod 32. The center of the outer cylindrical surface of the centralizer body 381 is provided with a plurality of mounting grooves 3811 for mounting the friction bodies 383, and the supporting elastic body 382 can provide a force to the friction bodies 383 in a direction away from the bottom of the mounting grooves 3811. The upper end of the centralizer body 381 extends into the second slip bowl 371 and is connected to the lower end of the second slip bowl 372 by screws in conjunction with the slip bowl retraction springs 373. Specifically, referring to fig. 9, the support elastic body 382 is the bow spring 144, the middle portion of the bow spring 144 abuts against the friction body 383, and both ends of the bow spring 144 abut against the bottom of the mounting groove 3811.

The upper thread of the center rod 32 is connected with the joint section 31 of the sand blasting component with pressure guiding, the lower part is connected with the centralizing locator 4, the lower part of the outer surface of the center rod 32 is provided with a specific guide rail groove, namely a plurality of long rail grooves 322 or a plurality of short rail grooves 323, so that the axial movement and guiding functions of the centralizing guide body assembly 38 are met, and the upper part of the center rod 32 is welded with hard alloy in a spraying way and is provided with a buffer pit, thereby avoiding the influence of fracturing fluid in an oil pipe on the erosion of the oil pipe.

The upper end face of the central rod 32 is provided with a buffer groove 325, the central rod 32 is internally provided with a blind hole 321 with a downward opening, the outer cylindrical surface of the central rod 32 is provided with a plurality of long track grooves 322 and a plurality of short track grooves 323 which extend along the axial direction and are arranged at intervals, the lower ends of the long track grooves 322 and the short track grooves 323 are mutually communicated through reversing guide rail grooves 324, and the upper end of the long track grooves 322 is higher than the upper end of the short track grooves 323. The guide pin 386 can slide along the long rail groove 322 or the short rail groove 323.

The cone comprises a cone cap 35 and a cone 36, the cone 36 is connected on the central rod 32 in a penetrating way, and the direction towards the slip assembly 37 is the smaller end of the radial section area of the cone, so that the outward expansion supporting effect of the second slip teeth 372 in the slip assembly 37 is met. The inner wall of the cone cap 35, the inner wall of the cone 36 and the outer wall of the central rod 32 together form a first mounting cavity 314, the central rod 32 is provided with an annular protrusion 326, the cone cap 35 is connected with the annular protrusion 326 through a shear pin 315, and after the shear pin 315 is sheared, the annular protrusion 326 can slide in the first mounting cavity 314.

Referring to fig. 12 to 14, the righting locator 4 includes a righting body 41, a platen 42, a plurality of locating bodies 43, and a plurality of elastic members. The righting body 41 is formed as a whole from bottom to top by a guide head 414, a righting body 413, an intermediate body 412 and a fourth upper joint 411. The pressing plate 42 is fixed on the righting body 41 by bolts 46; the positioning body 43 is engaged in the pressing plate 42 and can float in the radial direction.

The elastic member is installed inside the positioning body 43 to play a role in supporting the positioning body 43, so that the positioning body 43 is ensured to be always in the maximum allowable size. When the combined tool string moves in the casing, a certain gap is formed at the joint of the casing, and when the locating body 43 passes through the gap, the tip outside the locating body 43 stretches into the casing gap, so that the lifting force (friction force) of the tubular column is changed, and the logging depth of the tool can be determined through the ground depth metering device.

Referring to fig. 13 and 14, the guide head 414 is a hemisphere. At least three centralizing bulges 4131 are uniformly distributed on the centralizing body 413 along the circumferential direction, and the surfaces of the centralizing bulges 4131 are arc surfaces. The intermediate body 412 is a cylinder, and at least three connecting grooves 4121 uniformly distributed along the circumferential direction are formed on the cylindrical surface of the cylinder.

Referring to fig. 13 to 14, in the present embodiment, the number of the connecting grooves 4121, the positioning body 43 and the elastic members is three, and the number of the centralizing protrusions 4131 is six. The three positioning bodies 43 are respectively connected in the corresponding connecting grooves 4121, each positioning body 43 is provided with a positioning protrusion 433, the surface of each positioning protrusion 433 is a plane or an arc surface, the length of each positioning protrusion 433 is smaller than the width of a gap between two adjacent sleeves, and each positioning protrusion 433 is made of hard alloy. The positioning protrusion 433 is provided with a first guide section 435 and a first guide section 436 on both sides, and the first guide section 435 is disposed near the centralizer 413. It will be appreciated that the number of the connecting grooves 4121, the positioning body 43 and the elastic members may be four or may be set according to the actual situation.

An elastic member is provided between the groove bottom of the connecting groove 4121 and the positioning body 43, and the elastic member can provide a force to the positioning body 43 in a radial direction of the cylinder away from the cylinder for supporting the positioning body 43 and floating the positioning body 43 in the radial direction. Specifically, the elastic member is a leaf spring 44, the positioning body 43 is provided with a limiting groove 431, and the length of the limiting groove 431 is adapted to the compressed length of the leaf spring 44. In this embodiment, two compression springs 45 are further disposed in the connecting slot 4121, an upper limiting groove 432 is disposed on the positioning body 43, a lower limiting groove 4122 corresponding to the position of the upper limiting groove 432 is disposed on the bottom surface of the first positioning slot, a first end of the compression spring 45 is disposed in the upper limiting groove 432, and a second end of the compression spring 45 is disposed in the lower limiting groove 4122.

The positioning body 43 is provided with two mounting edges 434, the two mounting edges 434 are respectively positioned at two sides of the positioning body 43 in the length direction, and the surface of the mounting edge 434 is lower than the surface of the positioning body 43; the two ends of the connecting groove 4121 are provided with the pressing plate 42, the pressing plate 42 comprises two limiting parts and two connecting parts, the connecting parts are located on the outer sides of the limiting parts, the connecting parts are connected to the righting body 41 through bolts 46, the limiting parts correspond to two mounting edges 434 of the positioning body 43, the positioning body 43 is limited, the surface of the pressing plate 42 is flush with the surface of the positioning body 43 when reaching a preset position, and therefore the pressing plate 42 can prevent the positioning body 43 from continuing to be far away from the righting body 41 after reaching the preset position.

The working principle of the old well dragging fracturing clamping distance adjustable combination tool provided by the embodiment of the application is as follows:

after the tool string is put into the well, as the centralizing guide body assembly 38 of the track type bottom sealing packer 3 comprises the friction body 383, the telescopic piston pipe 29 is compressed and retracted into the cylinder barrel outer pipe 210 after the combined tool string is put into the well, so that the length of the whole tool string can be shortened, and the tool string is beneficial to the well. After the combined tool string is judged to be lowered to a designated position according to the centralizing locator 4, the length of the perforating section is determined by combining stratum data, the lower sealing and clamping point of the combined tool string is accurately ensured to be positioned at the lower part of the perforating section, the upper sealing point of the telescopic piston tube 29 is positioned at the upper part of the perforating section after being extended, and the upper sealing point and the lower sealing point are ensured to completely cover the perforating section.

The righting body 41 in the righting locator 4 is used for righting the combined tool string, after the locating body 43 is in clearance contact with the sleeve pipe joint, the friction force of the pipe column changes, the descending depth of the combined tool string can be calculated according to the number of friction force changes, after the combined tool string is judged to be descended to a designated position, firstly, the combined tool string is lifted up, the guide pins 386 slide to the reversing guide rail groove 324 along the short rail groove 323 due to the action of the friction body 383, then the combined tool string is descended, the guide pins 386 are switched to the long rail groove 322 through the reversing guide rail groove 324 and slide, the annular protrusions 326 apply downward thrust to the cone 36, the cone 36 pushes the second slip seat 371 to enable the second slip seat 372 to be clamped with the sleeve pipe, the combined tool string is continuously descended, and the main sealing rubber sleeve 33 deforms under the extrusion action to realize sealing of the lower part of the perforating section.

Then, the pipe column is lifted up to ensure that the extension length of the telescopic piston pipe meets the requirement, the ground fracturing equipment supplies fracturing fluid into the pipe column, when the fracturing fluid passes through the orifice of the hydraulic internal pressurizing packer 2 with the telescopic joint, a throttling pressure difference is formed, the fracturing fluid at the upper part of the orifice enters into the piston cavity along the second hydraulic channel 212, the piston is pushed to move upwards, the first sealing rubber sleeve 22 is compressed, and the annulus between the outer cylinder 24 and the casing is sealed. Thus, a double-seal single-card fracturing sealing section is formed. The pulling force of the extension piston tube 29 is less than the friction force formed by the friction body 383 of the bottom seal packer, otherwise, when the extension piston tube 29 is lifted up, the bottom seal is unsealed. The lower periphery of the outer tube of the telescopic piston tube 29 is provided with a pressure relief slit 2101, so that when the second piston 28 stretches out, liquid flows out between the telescopic piston tube 29 and the outer tube 210.

Finally, the high pressure fluid in the casing enters the hydraulic drive assembly 12 to push the two cone sleeves 125 to move in opposite directions along the axial direction, radially prop open the first slip teeth 143, and clamp the inner wall of the casing, so that the double-seal double-clamp perforation section seal of the whole combined tool string is formed.

Claims (10)

1. The utility model provides an old well drags fracturing clamping distance adjustable combination tool which characterized in that: the hydraulic pressure type hydraulic pressure well packer comprises a bidirectional hydraulic slip (1), a hydraulic pressure type internal pressurizing packer (2) with expansion joints, a track type bottom sealing packer (3) and a centralizing positioner (4) which are sequentially connected in series from top to bottom;

the bidirectional hydraulic slips (1) are used for being clamped with the upper part of the perforating section;

the hydraulic internal pressurizing packer (2) with the telescopic joint comprises a hydraulic packing assembly and a telescopic assembly connected below the hydraulic packing assembly;

the hydraulic packing assembly comprises a second central tube (25) and an outer tube (24), and is used for sealing the upper part of the oil well fracturing section;

the telescopic assembly comprises a cylinder outer tube (210) and a telescopic piston tube (29) arranged in the cylinder outer tube (210);

the cylinder barrel outer tube (210) of the telescopic assembly is fixed with the lower end of the outer tube (24);

a second piston (28) is fixed at the top end of the telescopic piston tube (29), and the second piston (28) is in sliding fit with the side wall of the inner cavity of the cylinder tube (210);

the inner side surface of the lower end of the cylinder barrel outer tube (210) is provided with a guide sleeve (211), the telescopic piston tube (29) is in sliding fit with the inner side wall of the guide sleeve (211), and the second piston (28) can be abutted with the guide sleeve (211) when sliding along with the telescopic piston tube (29) to the maximum distance;

the lower end of the cylinder barrel outer tube (210) is provided with a plurality of pressure relief slits (2101) extending along the axial direction, the pressure relief slits (2101) are positioned at the position, close to the guide sleeve (211), of the cylinder barrel outer tube (210), and the pressure relief slits (2101) penetrate through the cylinder barrel outer tube (210) along the radial direction;

the second central tube (25) is communicated with the telescopic piston tube (29);

the lower end of the telescopic piston tube (29) is provided with threads for connecting with a joint section (31) of the track type bottom sealing packer (3);

the bidirectional hydraulic slip (1) is provided with a first central pipe (13); the upper end of a second central tube (25) of the hydraulic packing assembly is connected with the first central tube (13);

the righting locator (4) is used for locating the tool string when the tool string is lowered and ensuring that the tool string is positioned in the center of the casing.

2. The old well dragging fracturing truck-spacing adjustable combination tool according to claim 1, wherein: the width of the pressure relief slit (2101) is smaller than the particle diameter of the fracturing sand or ceramsite in the oil well.

3. The old well dragging fracturing truck-spacing adjustable combination tool according to claim 2, wherein: the hydraulic packing assembly further comprises a first sealing rubber sleeve (22) and a first piston (23) which are arranged outside the second central tube (25);

the first sealing rubber sleeve (22) is arranged between the second upper joint (21) and the outer cylinder (24), the upper end of the first piston (23) extends out of the outer cylinder (24) and is in butt joint with the first sealing rubber sleeve (22), and the lower end of the first piston (23) extends into the space between the outer cylinder (24) and the second central tube (25).

4. The old well dragging fracturing truck-spacing adjustable combination tool according to claim 3, wherein: the hydraulic internal pressurizing packer (2) with the telescopic joint further comprises a throttling assembly arranged between the hydraulic packing assembly and the telescopic assembly;

the throttling assembly comprises a throttling sleeve (213), a magnetic seat (26) which is arranged on the inner side of the lower part of the throttling sleeve (213) and magnetically attracts a second piston (28), and a throttling mouth (27) which is arranged on the inner side of the magnetic seat (26); the throttle mouth (27) is provided with a throttle hole, the diameter of the radial section of the throttle hole is smaller than that of the radial section of the second central tube (25), and the throttle hole is communicated with the second central tube (25) and the telescopic piston tube (29);

the throttling sleeve (213) is arranged between the outer cylinder (24) and the outer cylinder tube (210); the upper section of the throttling sleeve (213) stretches into the space between the outer cylinder (24) and the second central tube (25), the lower section stretches into the space between the outer cylinder tube (210) and the magnetic seat (26), and the middle section protrudes outwards and is abutted with the outer cylinder (24) and the outer cylinder tube (210);

the throttling sleeve (213) has a fourth flow passage (2121); the fourth flow passage (2121) is arranged at the upper section of the throttling sleeve (213), extends along the axial direction of the throttling sleeve (213) and penetrates the throttling sleeve (213) upwards; the upper end of the throttling sleeve (213) is provided with a gap with the lower end of the first piston (23), and the gap is communicated with the fourth flow passage (2121);

a throttling sleeve is embedded at the lower part of the second central tube (25), a plurality of third flow passages (2123) are arranged on the side wall of the throttling sleeve, and the third flow passages (2123) penetrate through the throttling sleeve along the radial direction; a second ring groove (2122) is arranged between the throttling sleeve and the middle section of the throttling sleeve (213), and the second ring groove (2122) is communicated with the third flow passage (2123) and the fourth flow passage (2121).

5. The old well dragging fracturing truck-spacing adjustable combination tool according to any one of claims 1-4, wherein: the bidirectional hydraulic slip (1) comprises a first upper joint (11), a first central pipe (13), a plurality of bidirectional slip assemblies (14) arranged outside the first central pipe (13), a hydraulic driving assembly (12) and a first lower joint (15), wherein the hydraulic driving assembly is symmetrically arranged at the upper end and the lower end of the bidirectional slip assemblies (14);

the plurality of bi-directional slip assemblies (14) are uniformly distributed along the central axis of the first central tube (13); the inner side of the two-way slip assembly (14) is provided with an inner conical surface;

the hydraulic driving assembly (12) comprises a pressing sleeve (121), a first connecting sleeve (122), a supporting ring (123), a second connecting sleeve (124) and a taper sleeve (125);

one end of a compression sleeve (121) and one end of a first connecting sleeve (122) of one hydraulic driving assembly (12) are connected with a first upper joint (11); one end of a pressing sleeve (121) and one end of a first connecting sleeve (122) of the other hydraulic driving assembly (12) are connected with a first lower joint (15); a gap is formed between the other end of the first connecting sleeve (122) and the taper sleeve (125);

the other end of the taper sleeve (125) is provided with an outer conical surface matched with the inner conical surface of the two-way slip assembly (14); the first connecting sleeve (122) and the second connecting sleeve (124) are axially connected in series;

the middle part of the first connecting sleeve (122) is connected with the supporting ring (123) in a sealing way, and a first runner which extends along the axial direction of the supporting ring (123) and penetrates through the side wall of the supporting ring (123) in the radial direction is arranged on the side wall of the supporting ring (123);

the inner side of the first connecting sleeve (122) is provided with an annular cavity and a second flow passage which penetrates through the first connecting sleeve (122) along the axial direction and towards the direction close to the bidirectional slip assembly (14), the first flow passage, the annular cavity and the second flow passage form a first hydraulic passage, and the first hydraulic passage is used for driving the taper sleeve (125) to compress the bidirectional slip assembly (14) under the action of high-pressure liquid to realize clamping.

6. The old well dragging fracturing truck-spacing adjustable combination tool according to claim 5, wherein: the track type bottom sealing packer (3) comprises a joint section (31) and a center rod (32) which are sequentially connected in series from top to bottom, wherein the center rod is connected below the joint section (31); the device also comprises a main sealing rubber sleeve (33), a conical body, a slip assembly (37) and a centralizing guide body assembly (38) which are sequentially sleeved on the outer side of the central rod (32) from top to bottom;

the joint section (31) comprises an upper connecting section used for being connected with an oil pipe, a lower connecting section connected with a central rod (32) and a pressure guiding sand blasting assembly arranged between the upper connecting section and the lower connecting section;

the pressure guiding sand blasting assembly comprises a plurality of guiding sand outlets (312) which are uniformly distributed along the circumferential direction;

the centralizing guide body assembly (38) comprises a centralizing body main body (381), the centralizing body main body (381) is provided with a mounting groove (3811), the mounting groove (3811) is provided with a friction body (383) which is used for being in friction fit with a sleeve, and the lower end of the centralizing guide body assembly (38) is provided with a guide pin (386) which protrudes inwards;

the outer surface of the lower section of the central rod (32) is axially provided with a guide rail groove; the guide rail grooves comprise a plurality of long guide rail grooves (322) and a plurality of short guide rail grooves (323) which extend along the axial direction, and reversing guide rail grooves (324) which are connected with the lower ends of the long guide rail grooves (322) and the lower ends of the short guide rail grooves (323) and correspond to each other; the long guide rail groove (322) and the short guide rail groove (323) are arranged at intervals along the circumferential direction;

the guide pin (386) mates with the guide rail groove.

7. The old well dragging fracturing truck-spacing adjustable combination tool of claim 6, wherein: the slip assembly (37) comprises a plurality of slip components, each slip component comprises a second slip base (371), a plurality of second slip teeth (372) and a plurality of second slip teeth retraction springs (373), the upper ends of the second slip teeth (372) extend out of the upper ends of the second slip bases (371), and the lower ends of the second slip teeth (372) are connected in the second slip bases (371) through the second slip teeth retraction springs (373);

the second slip bowl (371) is connected to the centralizer body (381).

8. The old well dragging fracturing truck-spacing adjustable combination tool of claim 7, wherein: the cone comprises a cone cap (35) surrounding the central rod (32) and a cone (36) connected below the cone cap (35); a first mounting cavity (314) is formed among the cone cap (35), the cone (36) and the central rod (32);

the central rod (32) is provided with an annular bulge (326), and the annular bulge (326) is arranged in the first mounting cavity (314);

the guide pin (386) is matched with the top end of the short guide rail groove (323), and a gap exists between the annular bulge (326) and the inner surface of the lower side of the first mounting cavity (314);

alternatively, the guide pins (386) engage the top ends of the long rail grooves (322) and the annular protrusions (326) push down the cone (36) into between the slip bowl and the center rod (32).

9. The old well dragging fracturing truck-spacing adjustable combination tool of claim 8, wherein: the righting positioner (4) comprises a guide righting assembly and a plurality of positioning assemblies which are fixedly connected;

the guide righting assembly comprises a righting body (41), a connecting groove (4121) arranged on the righting body (41) and a plurality of lower limit grooves (4122) arranged in the connecting groove (4121);

the positioning assembly comprises a positioning body (43), a limiting groove arranged on the positioning body (43) and an upper limiting groove (432) arranged corresponding to the lower limiting groove (4122);

a compression spring (45) is arranged in a cavity formed by the lower limit groove (4122) and the upper limit groove (432), and an elastic piece is arranged between the limit groove and the connecting groove (4121) and used for supporting the positioning body (43) and enabling the positioning body (43) to float along the radial direction.

10. The old well dragging fracturing truck-spacing adjustable combination tool of claim 9, wherein: the positioning body (43) comprises a positioning protrusion (433), and a first guide section (435) and a second guide section (436) which are arranged on two sides of the positioning protrusion (433), wherein the end face of the positioning protrusion (433) is an arc face.