CN207499844U - With brill pipeline scraper - Google Patents

Abstract

The utility model provides a pipe scraper while drilling, which includes an upper joint, a central pipe, a conversion joint and a lower joint connected in sequence, wherein: the central pipe is provided with a plurality of pipe scrapers at intervals along its circumferential direction, A ball seat is connected inside the conversion joint, and in the state where a sealing ball is set on the ball seat, each scraper bar can be moved from the center tube under the action of the liquid pressure flowing into the center tube. Extend radially outward. The pipe scraper while drilling of the utility model can effectively solve the technical problem of scraping pipe while drilling during drilling, and greatly saves drilling time and drilling cost.

Description

Scraper while drilling

technical field

The utility model relates to the technical field of drilling engineering, in particular to a multifunctional pipe scraper while drilling.

Background technique

During the drilling process, with the continuous increase of the well depth, in order to save the completion cost or other comprehensive considerations, the oil field generally adopts the liner cementing technology for cementing operations. The characteristic of liner cementing is to hang the liner on the inner wall of the upper technical casing through the liner hanger technology.

In order to realize the effective implementation of the liner cementing operation and facilitate the effective setting and hanging of the liner hanger, the cleaning operation of the inner wall must be carried out on the inner wall of the upper technical casing, that is, the wall scraping operation. In order to realize the effective wall scraping operation, the conventional technical method is to run the drilling tool assembly for drilling the well after the drilling is completed, and then run the wall scraper for the wall scraping of the technical casing after the drilling operation is completed. Operation.

Conventional technical means guarantee the effective casing wall scraping to a certain extent. However, with the continuous development of drilling technology, deep wells and ultra-deep wells have become the focus of drilling development. When performing wall scraping operations in deep and ultra-deep wells, Since the conventional wall scraping operation requires tripping and replacing the drilling tool assembly, the process is complicated, the cycle is long, and the cost is high. With the slump in international oil prices, in order to reduce costs and improve drilling efficiency, how to realize drilling while drilling? Wall scraping has become one of the technical problems to be solved urgently in deep wells and ultra-deep wells.

Utility model content

The purpose of the utility model is to provide a pipe scraper while drilling, which can effectively solve the technical problems of pipe scraping while drilling, and greatly save drilling time and drilling cost.

Above-mentioned purpose of the utility model can adopt following technical scheme to realize:

The utility model provides a pipe scraper while drilling, which includes an upper joint, a central pipe, a conversion joint and a lower joint connected in sequence, wherein: the central pipe is provided with a plurality of pipe scrapers at intervals along its circumferential direction, The conversion joint is connected with a ball seat, and in the state where a sealing ball is set on the ball seat, each of the scraper strips can be moved from the center tube under the action of the liquid pressure flowing into the center tube. Extend radially outward.

In an embodiment of the present utility model, an upper outer sliding sleeve and a lower outer sliding sleeve are provided on the upper sleeve of the central tube; the upper end of the upper outer sliding sleeve is connected with the upper joint through an upper shear pin, so that The lower end of the upper outer sliding sleeve is in contact with the plurality of scraper bars; the upper end of the lower outer sliding sleeve is in contact with the plurality of scraper bars, and the lower end of the lower outer sliding sleeve is in contact with the conversion joint They are connected by a lower shear pin.

In an embodiment of the present utility model, the fixed sleeve on the central tube is provided with an upper fixed sleeve and a lower fixed sleeve; the upper fixed sleeve is located in the upper outer sliding sleeve and is slidably sealed with the upper outer sliding sleeve It is provided that an upper hydraulic chamber is formed between the upper outer sliding sleeve and the upper fixed sleeve; the lower fixed sleeve is located in the lower outer sliding sleeve and is arranged to slide and seal with the lower outer sliding sleeve, and the lower A lower hydraulic chamber is formed between the outer sliding sleeve and the lower fixed sleeve; the central pipe is provided with an upper liquid flow hole communicating with the upper hydraulic chamber and a lower liquid flow hole communicating with the lower hydraulic chamber. hole.

In an embodiment of the present utility model, when the upper shearing pin and the lower shearing pin are cut off, the upper outer sliding sleeve moves up and is limited to the upper joint, and the lower outer sliding sleeve The sliding sleeve moves down and is limited to the conversion joint, the plurality of scraper strips protrude radially outward from the central tube, and the upper end of each scraper strip is against the upper fixing sleeve, The lower end of the scraper bar is against the lower fixing sleeve.

In an embodiment of the present utility model, the upper ends of each of the scraper bars are respectively provided with a first step portion and a second step portion abutting against the upper outer sliding sleeve; the lower ends of each of the scraper bars are respectively provided with There are a third step and a fourth step abutting against the lower outer sliding sleeve.

In an embodiment of the present utility model, two first arc-shaped steps and two second arc-shaped steps are provided on the outer wall of the central tube, and the outer diameter of the first arc-shaped steps is larger than that of the The outer diameter of the second arc-shaped step portion; the first step portion of the plurality of scraper bars is abutted by the upper outer sliding sleeve, and the third step portion of the plurality of scraper bars is abutted by the lower In the state where the outer sliding sleeve abuts, the outer diameters of the two first arc-shaped steps are the same as the outer diameters of the first step and the third step, and the two second arcs The outer diameters of the shaped stepped portions are respectively the same as the outer diameters of the second stepped portion and the fourth stepped portion.

In an embodiment of the present utility model, a plurality of accommodating grooves are arranged at intervals along the circumferential direction of the central tube, the scraping pipe strip is installed in the accommodating groove, and the scraping pipe strip has a scraping pipe strip A body and a plurality of elastic parts, the plurality of elastic parts are interposed between the accommodating groove and the scraper bar body, and the outer wall of the scraper bar body is provided with a plurality of scraper ribs.

In an embodiment of the present utility model, a lower outer cylinder is connected between the conversion joint and the lower joint, a tee basket is connected to the lower joint, and a plurality of through holes are provided on the tee basket.

In an embodiment of the present utility model, the upper joint is provided with an upper flow hole, the conversion joint is provided with a lower flow hole, and an upper flow chamber is formed between the upper outer sliding sleeve and the upper joint. The upper flow chamber communicates with the upper flow hole, and a lower flow chamber is formed between the lower outer sliding sleeve and the conversion joint, and the lower flow chamber communicates with the lower flow hole.

In an embodiment of the present utility model, there are three scraper bars, and the three scraper bars are arranged at equal intervals along the circumferential direction of the central tube.

The characteristics and advantages of the pipe scraper while drilling of the utility model are: the pipe scraper while drilling can be pulled out into the upper technical casing after the drilling is completed, and the wall scraping operation can be realized directly, and it is also suitable for drilling after the drilling is completed. The wall scraping operation in the upper technical casing is also suitable for the wall scraping operation after the drill plug is completed. Therefore, the scraper while drilling greatly reduces the operation time for wall scraping due to the replacement of the drilling tool assembly in the conventional wall scraping operation , improve drilling efficiency, save drilling costs, and provide technical support for the smooth progress of subsequent liner cementing operations. The utility model can greatly reduce the tripping operation due to the scraping operation in conventional liner cementing, and can greatly save the drilling and completion costs in deep wells and ultra-deep wells. operation characteristics.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings that need to be used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some implementations of the present invention. For example, those of ordinary skill in the art can also obtain other drawings based on these drawings on the premise of not paying creative efforts.

Fig. 1 is a half-sectional schematic diagram of a pipe scraper while drilling of the present invention.

Fig. 2 is a sectional view along the line A-A of Fig. 1 .

Fig. 3 is a front sectional view of the scraper bar body of the present invention.

Fig. 4 is a top view of the scraper bar body of the present invention.

Fig. 5 is a half-sectional view of the central tube of the present invention.

Fig. 6 is a sectional view taken along line B-B of Fig. 1 .

Fig. 7 is a half-sectional schematic diagram of a state in which the scraper bar of the pipe scraper while drilling of the present invention protrudes radially outward from the center pipe.

Fig. 8 is a half-sectional schematic diagram of the state where the ball seat and the sealing ball of the pipe scraper while drilling of the present invention are dropped to the ball seat basket.

Fig. 9 is a cross-sectional view along line C-C of Fig. 7 .

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. example. Based on the embodiments of the present utility model, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the scope of protection of the present utility model.

As shown in Figure 1, the utility model provides a pipe scraper while drilling, which includes an upper joint 1, a central pipe 2, a conversion joint 3 and a lower joint 4 connected in sequence, wherein: the central pipe 2 is A plurality of scraper strips 5 are arranged at intervals in the circumferential direction, and a ball seat 31 is connected inside the conversion joint 3 , and when a sealing ball 32 is set on the ball seat 31 , each scraper strip 5 Under the action of the pressure of the liquid entering the central tube 2, it can protrude radially outward from the central tube 2.

Specifically, the upper end of the upper joint 1 is provided with a standard drill collar box 11, which can be connected with the drill collar pin; the lower end of the lower joint 4 is provided with a standard drill collar pin 41, which can be connected with the drill collar box. The pipe scraper while drilling of the present utility model, when in use, its upper end connects upper drill collar or drill pipe through upper joint 1, and its lower end connects lower drill collar or drill pipe through lower joint 4.

The upper end of the central tube 2 is threadedly connected with the lower end of the upper joint 1, and the static seal is realized through an O-ring 12 between the two; the lower end of the central tube 2 is threaded with the upper end of the adapter 3, and the two are sealed through an O The ring 33 realizes static sealing; in this embodiment, the lower end of the adapter 3 is threadedly connected with the lower outer cylinder 6, and the lower end of the lower outer cylinder 6 is threaded with the lower joint 4, and the upper end of the lower outer cylinder 6 is connected with the adapter 3. The static sealing is realized by the O-ring 61 between them, and the static sealing is realized by the O-ring 62 between the lower end of the lower outer cylinder 6 and the lower joint 4 .

The scraper bar 5 is used to realize the wall scraping operation on the inner wall of the technical casing. A plurality of scraper bars 5 of the utility model are arranged at intervals along the circumferential direction of the central tube 2, and the number of scraper bars 5 can be two or three. Or four etc., do not limit here; In the present embodiment, the quantity of scraping pipe strip 5 is three, and three scraping pipe strips 5 are arranged at equal intervals along the circumferential direction of central tube 2, adopt three scraping pipe strips 5. It can not only ensure sufficient scraping of the pipe, but also ensure the strength of the central pipe 2.

In this embodiment, the central tube 2 is provided with a plurality of accommodation grooves 21 at intervals along its circumferential direction, and the scraper strip 5 is installed in the accommodation grooves 21. The scraper strip 5 has a scraper strip body 51 and a plurality of The elastic member 52 is interposed between the accommodating groove 21 and the scraper bar body 51 , and the outer wall of the scraper bar body 51 is provided with a plurality of scraper ribs 511 .

Specifically, please refer to FIG. 3 and FIG. 4, the scraper bar body 51 is generally in the shape of a strip, and the inner side 512 in contact with the bottom wall of the accommodating groove 21 of the central tube 2 is a plane structure, and the scraper bar body 51 is in a flat structure. The inner side 512 of the strip body 51 is designed as a plane structure to fit with the bottom wall of the accommodating groove 21 of the central tube 2 and also to ensure the strength of the tool in a limited space.

A plurality of scraper ribs 511 are arranged on the middle outer wall of the scraper bar body 51. In this embodiment, the scraper ribs 511 are formed into a spiral structure, and between two adjacent scraper ribs 511 A helical groove 517 is formed, and a plurality of scraper ribs 511 of the helical structure are used for the scraping operation, which can not only ensure the smooth progress of the scraper, but also ensure the contact between the inner wall of the casing and the helical structure during the operation. The effective flow of the drilling fluid ensures that the contact state between the helical structure and the inner wall of the casing is point contact rather than surface contact.

Further, a first stepped portion 513 and a second stepped portion 514 are respectively provided at the upper end of the scraper strip body 51 of the scraper strip 5, and a third stepped portion 515 and a fourth stepped portion are respectively provided at the lower end of the scraper strip body 51. The step portion 516, wherein the first step portion 513 and the third step portion 515 are respectively located at the upper end and the lower end of the plurality of scraper ribs 511, the second step portion 514 is located at the upper end of the first step portion 513, and the fourth step portion 516 Located at the lower end of the third step portion 515 .

Furthermore, in order to cooperate with the structure of the first step portion 513, the second step portion 514, the third step portion 515 and the fourth step portion 516 of the scraper strip 5, in this embodiment, as shown in FIG. 5, Two first arc-shaped steps 22 and two second arc-shaped steps 23 are arranged on the outer wall of the central tube 2, and the outer diameter of the first arc-shaped steps 22 is larger than the outer diameter of the second arc-shaped steps 23. path. Please refer to FIG. 2 , under the condition that each scraper bar 5 is accommodated in the corresponding accommodation groove 21 in the central tube 2, the outer diameters of the two first arc-shaped steps 22 are respectively in line with the first step. The outer diameters of the second stepped portion 513 and the third stepped portion 515 are the same, and the outer diameters of the two second arc-shaped stepped portions 23 are the same as the outer diameters of the second stepped portion 514 and the fourth stepped portion 516 .

The inner side 512 of the scraper bar 5 is provided with a plurality of installation holes 518 at intervals along the axial direction of the central tube 2, and each installation hole 518 is used to place an elastic member 52. In this embodiment, the elastic member 52 is a compression spring , and each scraper bar 5 has three elastic pieces 52, of course, in other embodiments, the number of elastic pieces 52 can also be selected and set according to actual needs, which is not limited here. Further, as shown in FIG. 2 and FIG. 3 , counterbore holes 211 for accommodating the elastic member 52 are also provided in each accommodation groove 21 of the central tube 2 , and in each installation hole 518 of the scraper bar body 51 A groove 5181 for accommodating the elastic member 52 is also provided.

In the embodiment of the present utility model, the upper outer sliding sleeve 24 and the lower outer sliding sleeve 25 are set on the central tube 2; , the lower end of the upper outer sliding sleeve 24 is in contact with a plurality of scraper bars 5; the upper end of the lower outer sliding sleeve 25 is in contact with a plurality of scraper bars 5; The space is connected by the lower shear pin 251.

Specifically, in this embodiment, the upper outer sliding sleeve 24 is generally in the shape of a cylinder, which is sheathed on the central pipe 2, and the upper end of the upper outer sliding sleeve 24 is inserted between the upper joint 1 and the central pipe 2, and Connected to the lower end of the upper joint 1 through the upper shear pin 241 ; The lower outer sliding sleeve 25 is generally in the shape of a cylinder, which is sheathed on the central tube 2. The lower end of the lower outer sliding sleeve 25 is inserted between the central tube 2 and the adapter 3, and is connected to the adapter through the lower shear pin 251. The upper end of the joint 3 ; the upper end of the lower outer sliding sleeve 25 is sheathed outside the lower ends of the plurality of scraper bars 5 and abuts against the third step portion 515 of the plurality of scraper bars 5 . Therefore, the plurality of scraper bars 5 are radially limited in the plurality of accommodating grooves 21 of the central tube 2 under the action of the upper outer sliding sleeve 24 and the lower outer sliding sleeve 25 .

Further, the central tube 2 is also fixed with an upper fixed sleeve 26 and a lower fixed sleeve 27; the upper fixed sleeve 26 is located in the upper outer sliding sleeve 24 and is arranged to slide and seal with the upper outer sliding sleeve 24, and the upper outer sliding sleeve An upper hydraulic chamber 242 is formed between 24 and the upper fixed sleeve 26; the lower fixed sleeve 27 is located in the lower outer sliding sleeve 25 and is slidably sealed with the lower outer sliding sleeve 25, and the lower outer sliding sleeve 25 and the lower fixed sleeve 27 A lower hydraulic chamber 252 is formed between them; the central pipe 2 is provided with an upper liquid flow hole 28 communicating with the upper hydraulic chamber 242 and a lower liquid flow hole 29 communicating with the lower hydraulic chamber 252 .

Specifically, the upper fixing sleeve 26 is generally cylindrical in shape, which is sleeved on the central tube 2 and located in the upper outer sliding sleeve 24, and the upper and lower ends of the upper fixing sleeve 26 pass through the upper fixing half ring 261 and the lower fixing half ring respectively. The ring 262 is axially limited and fixed on the central tube 2, and a plurality of O-rings 263 are arranged between the upper fixed sleeve 26 and the central tube 2 to form a static seal, and the upper fixed sleeve 26 and the upper outer sliding sleeve 24 There are also a plurality of O-rings 264 between them. The upper outer sliding sleeve 24 can be sleeved on the outer side of the upper fixed sleeve 26 along the axial direction of the central tube 2 in a sealed and slidable manner. The upper fixed sleeve 26 and the upper outer sliding sleeve 24 A dynamic seal is formed between them; the lower fixed sleeve 27 is generally in the shape of a cylinder, which is sleeved on the central tube 2 and located in the lower outer sliding sleeve 25, and the upper and lower ends of the lower fixed sleeve 27 respectively pass through the upper fixed half ring 271 1. The lower fixed half ring 272 is axially limited and fixed on the center tube 2, a plurality of O-rings 273 are arranged between the lower fixed sleeve 27 and the central tube 2 to form a static seal, and the lower fixed sleeve 27 and the lower outer A plurality of O-rings 274 are also arranged between the sliding sleeves 25, and the lower outer sliding sleeve 25 can be sleeved on the outer side of the lower fixed sleeve 27 along the axial direction of the central tube 2 in a sealed and slidable manner. A dynamic seal is formed between the sliding sleeves 25 .

In the present utility model, upper hydraulic cavity 242 and lower hydraulic cavity 252 are formed between upper fixed sleeve 26 and lower fixed sleeve 27 and upper outer sliding sleeve 24 and lower outer sliding sleeve 25 respectively. When extending outward along the radial direction of the central tube 2 under the action of the member 52, the upper end surface of each scraper bar 5 will be limited on the slope of the upper fixing sleeve 26, and the lower end surface of each scraper bar 5 will be limited on the lower surface. The inclined surface of the fixed sleeve 27 forms an axial limit to avoid the vertical displacement of the scraper bar 5 during the scraping process, and in this state, the second step portion 514 and the fourth step of each scraper bar 5 The portion 516 is respectively limited by the upper outer sliding sleeve 24 and the lower outer sliding sleeve 25, thereby forming a radial limit.

When the drilling fluid is injected into the upper hydraulic chamber 242 through the upper liquid flow hole 28 of the central pipe 2, and the drilling fluid is injected into the lower hydraulic chamber 252 through the lower liquid flow hole 29 of the central pipe 2, the effect of the hydraulic pressure of the drilling fluid Next, the upper shear pin 241 is cut off, the upper outer sliding sleeve 24 will move up to the step surface 13 of the upper joint 1, and the lower outer sliding sleeve 25 will move down to the step surface 38 of the conversion joint 3, and a plurality of scraper strips 5 will protrude radially outward from the accommodation groove 21 of the central tube 2, the upper end surface of each scraper bar 5 will abut against the upper fixing sleeve 26, and the second step portion 514 at the upper end of each scraper bar 5 will abut against Connected to the inner side of the lower end of the upper outer sliding sleeve 24, the lower end surface of each scraper bar 5 will abut against the lower fixed sleeve 27, and the fourth step portion 516 at the lower end of each scraper bar 5 will abut against the bottom of the lower outer sliding sleeve 25. Inside the upper end, in this state, each scraper bar 5 is in the working state of scraping the wall.

A ball seat 31 is designed inside the conversion joint 3, and the ball seat 31 can be seated by the sealing ball 32. The axial positioning between the ball seat 31 and the conversion joint 3 is realized by a shear pin 37. Sealing is achieved by an O-ring seal 34 .

In the embodiment of the present utility model, a lower outer cylinder 6 is connected between the conversion joint 3 and the lower joint 4, and the lower joint 4 is connected with a ball seat basket 42, and the ball seat basket 42 is provided with a plurality of through holes 421.

Specifically, the lower outer cylinder 6, the conversion joint 3, and the lower joint 4 are respectively threaded together, and the static seal is realized through an O-ring. As shown in FIG. 6, the ball seat basket 42 and the lower joint 4 are threaded The ball seat basket 42 is designed with a plurality of through holes 421 for drilling fluid circulation. In this embodiment, a circular through hole 422 is provided in the middle of the ball seat basket 42. Both sides of the circular through hole 422 are respectively provided with two fan-shaped through holes 423. Of course, in other embodiments, the plurality of through holes 421 can also be of other shapes, which are not limited here, as long as the After the ball seat 31 is located on the ball basket seat 42, the drilling fluid can be effectively circulated.

In one embodiment of the present invention, the upper joint 1 is provided with an upper flow hole 14, the conversion joint 3 is provided with a lower flow hole 35, and an upper flow hole 35 is formed between the upper outer sliding sleeve 24 and the upper joint 1. cavity 15, the upper flow cavity 15 communicates with the upper flow hole 14, and a lower flow cavity 36 is formed between the lower outer sliding sleeve 25 and the adapter 3, and the lower flow cavity 36 communicates with the lower flow hole 35.

Specifically, when the upper shear pin 241 and the lower shear pin 251 are respectively sheared under the action of the hydraulic pressure of the drilling fluid, the upper outer sliding sleeve 24 moves upwards driven by the upper hydraulic chamber 242, and the lower outer sliding sleeve 25 Driven by the lower hydraulic chamber 252 to move downward, setting the upper flow chamber 15 and the lower flow chamber 36 can prevent the connection between the upper joint 1, the upper outer sliding sleeve 24, and the center pipe 2, as well as the transition joint 3, the lower outer sliding sleeve 25, A "dead space" is formed between the central tubes 2 to ensure effective movement of the upper outer sliding sleeve 24 and the lower outer sliding sleeve 25 .

During the use of the utility model, when the drilling or drilling or drilling of the ash plug is completed, the drill is pulled out into the technical casing, and when the hanging part of the hanger on the inner wall of the technical casing is scraped, the sealing ball 32 is put into the ground, When the sealing ball 32 is seated on the ball seat 31, the ground continues to pump drilling fluid. When the hydraulic pressure of the drilling fluid reaches the design value, under the action of the liquid pressure and the upper hydraulic chamber 242 and the lower hydraulic chamber 252, the upper shear The pin 241 and the lower shear pin 251 are cut off first, and the upper hydraulic chamber 242 and the lower hydraulic chamber 252 respectively drive the upper outer sliding sleeve 24 and the lower outer sliding sleeve 25 to slide to the upper end and the lower end and respectively limit the steps on the upper joint 1 At the step surface 38 on the surface 13 and the conversion joint 3, at the same time, because the plurality of scraper bars 5 lose the radial constraint, the scraper bars 5 protrude outward along the radial direction of the central tube 2 under the action of the elastic member 52 To the inner wall of the technical casing, with the up and down movement and rotation of the drill string, the wall scraping operation on the inner wall of the technical casing is realized. At the same time, during the wall scraping operation, in order to ensure the circulation of the drilling fluid, the ground continues to carry out the pressure holding operation. After the hydraulic pressure reaches a certain value, the shear pin 37 is cut off, and the sealing ball 32 and the ball seat 31 fall together. The ball seat basket 42, because the ball seat basket 42 is designed with a plurality of through holes 421, these through holes 421 can realize the effective circulation of the drilling fluid, avoiding the impact of the drilling fluid on the tool due to the scratching operation and other downhole operations. erosion and minimize tool pressure drop in confined spaces.

The pipe scraper while drilling of the utility model can realize direct wall scraping operation after drilling into the upper technical casing after the drilling is completed, and is also suitable for the wall scraping operation after the completion of drilling and the upper technical casing. The wall scraping operation after drilling the ash plug, therefore, the pipe scraper while drilling greatly reduces the operation time of wall scraping due to the replacement of the drilling tool assembly in the conventional wall scraping operation, improves drilling efficiency, saves drilling costs, and provides a good foundation for the subsequent liner Provide technical support for the smooth progress of cementing operations. The utility model can greatly reduce the tripping operation due to the scraping operation in conventional liner cementing, and can greatly save the drilling and completion costs in deep wells and ultra-deep wells. operation characteristics.

The above are only a few embodiments of the present utility model, and those skilled in the art can make various changes or modifications to the embodiments of the present utility model according to the contents disclosed in the application documents without departing from the spirit and scope of the present utility model.

Claims (10)

1. A pipe scraper while drilling is characterized in that it comprises an upper joint, a central pipe, a conversion joint and a lower joint connected in sequence, wherein: the central pipe is provided with a plurality of pipe scrapers at intervals along its circumferential direction, The conversion joint is connected with a ball seat, and in the state where a sealing ball is set on the ball seat, each of the scraper strips can be moved from the center tube under the action of the liquid pressure flowing into the center tube. Extend radially outward. 2. The pipe scraper while drilling as claimed in claim 1, wherein an upper outer sliding sleeve and a lower outer sliding sleeve are sheathed on the central pipe; the upper end of the upper outer sliding sleeve and the upper joint are connected by upper shear pins, the lower end of the upper outer sliding sleeve abuts against the plurality of scraper bars; the upper end of the lower outer sliding sleeve abuts against the plurality of scraper bars, and the lower The lower end of the outer sliding sleeve is connected with the transition joint through a lower shear pin. 3. The pipe scraper while drilling according to claim 2, characterized in that, the center pipe is also provided with an upper fixed sleeve and a lower fixed sleeve; the upper fixed sleeve is located in the upper outer sliding sleeve And it is arranged to slide and seal with the upper outer sliding sleeve, and an upper hydraulic chamber is formed between the upper outer sliding sleeve and the upper fixing sleeve; the lower fixing sleeve is located in the lower outer sliding sleeve and is connected to the lower The outer sliding sleeve is provided with a sliding seal, and a lower hydraulic chamber is formed between the lower outer sliding sleeve and the lower fixed sleeve; the upper liquid flow hole communicated with the upper hydraulic chamber and connected with the upper hydraulic chamber is provided on the central tube. The lower liquid flow hole communicated with the lower hydraulic chamber. 4. The pipe scraper while drilling according to claim 3, characterized in that, when the upper shear pin and the lower shear pin are cut off, the upper and outer sliding sleeves move upward and limit the position to the upper joint, the lower outer sliding sleeve moves down and is limited to the conversion joint, the plurality of scraper strips protrude radially outward from the central tube, and the upper end of each scraper strip abut against the upper fixing sleeve, and the lower end of each scraper bar abuts against the lower fixing sleeve. 5. The pipe scraper while drilling according to claim 3, characterized in that, the upper ends of each scraper bar are respectively provided with a first step and a second step that abut against the upper outer sliding sleeve; The lower end of each scraper bar is respectively provided with a third step portion and a fourth step portion abutting against the lower outer sliding sleeve. 6. The pipe scraper while drilling according to claim 5, wherein two first arc-shaped steps and two second arc-shaped steps are provided on the outer wall of the central pipe, and the first The outer diameter of the arc-shaped step is larger than the outer diameter of the second arc-shaped step; the first step of the plurality of scraper bars is abutted by the upper outer sliding sleeve, and the plurality of scraper bars When the third stepped portion of the bar is abutted by the lower outer sliding sleeve, the outer diameters of the two first arc-shaped stepped portions are respectively the same as the outer diameters of the first stepped portion and the third stepped portion The dimensions are the same, and the outer diameters of the two second arc-shaped stepped portions are respectively the same as the outer diameters of the second stepped portion and the fourth stepped portion. 7. The pipe scraper while drilling according to claim 1, characterized in that, the center pipe is provided with a plurality of accommodation grooves at intervals along its circumferential direction, and the scraper strip is installed in the accommodation grooves , the scraper bar has a scraper bar body and a plurality of elastic parts, the plurality of elastic parts are sandwiched between the accommodating groove and the scraper bar body, and the outer wall of the scraper bar body is set There are multiple scraper ribs. 8. The pipe scraper while drilling according to claim 1, wherein a lower outer cylinder is connected between the conversion joint and the lower joint, and a ball seat basket is connected to the lower joint, and the ball The seat basket is provided with a plurality of through holes. 9. The pipe scraper while drilling as claimed in claim 2, characterized in that, the upper joint is provided with an upper flow hole, the conversion joint is provided with a lower flow hole, and the upper and outer sliding sleeves are connected to the An upper flow cavity is formed between the upper joints, and the upper flow cavity communicates with the upper flow hole, and a lower flow cavity is formed between the lower outer sliding sleeve and the conversion joint, and the lower flow cavity communicates with the upper flow hole. The following flow holes are connected. 10 . The scraper while drilling according to claim 1 , wherein there are three scraper strips, and the three scraper strips are arranged at equal intervals along the circumferential direction of the central tube. 11 .