Drill bit synchronous rotation pipe scraper
Technical Field
The invention relates to the technical field of drilling equipment, in particular to a synchronous rotary drill bit pipe scraper.
Background
In the oilfield exploitation process, cement blocks, cement rings, hard wax, various salt crystals and sediments, perforation burrs, ferric oxide and the like generated after the casing is rusted are often attached to the casing inner barrel, so that a pipe scraper is required to be put down to clean the casing inner barrel under the well, the success rate of tool lowering and operation is improved, and the drift diameter of the casing is kept unchanged. The scraper is usually matched with a screw motor for use, and is arranged behind the drill bit and synchronously rotates with the drill bit, so that the inner wall of the sleeve is cleaned in the drilling process, and an additional lifting process is saved.
The most common drill bit synchronous rotation scraper is a spring type sleeve scraper, a scraper plate of the scraper is connected to a shell wall through a spring, and the scraper plate expands outwards and clings to the inner wall of the sleeve under the elastic extrusion action of the spring when in use, so that scraping work is realized. This structure has a drawback: if the inner diameter of the sleeve is larger, the spring is excessively stretched, so that the elastic extrusion force provided by the spring is insufficient, and the scraping effect is not ideal; if the inner diameter of the sleeve is smaller, the spring is excessively compressed, so that the elastic extrusion force provided by the spring is excessively large, and the scraper is easily damaged due to long-term high-strength scraping. Under the condition, if the inner sleeve barrel has thicker sections of cement blocks, various salt crystals, sediments and the like, the inner diameter of the section of sleeve barrel is reduced, if the scraper directly scrapes under the action of larger elastic extrusion force, the scraper is easily damaged, the sediment is harder to touch, and even the whole drilling tool is blocked and can not rotate.
Although the change amplitude of the inner diameter of the sleeve is not large in normal use, the small change of the amplitude can cause the large change of the elastic extrusion force of the spring due to the short length of the spring, so the defect is not ignored and needs to be solved.
Disclosure of Invention
The invention aims to provide a synchronous rotary pipe scraper for a drill bit, which solves the problems of damage to a scraper or unsatisfactory scraping effect caused by the fact that the elastic extrusion force of a spring in a traditional spring type sleeve pipe scraper changes along with the change of the inner diameter of a sleeve pipe.
The invention realizes the above purpose through the following technical scheme:
The utility model provides a drill bit synchronous rotation scraper, includes the barrel, it has a plurality of mounting groove to open on the section of thick bamboo wall of barrel, there is the scraper plate through first spring coupling in the mounting groove, still be equipped with the second spring that the elastic coefficient is greater than first spring far in the mounting groove, the second spring top is equipped with the fly leaf, the bottom of first spring is installed on the fly leaf, fly leaf one end is connected with the trace, the trace end stretches out to the barrel outside, and the trace has the space of outwards stretching out or inwards shrink, and when the trace outwards stretches out, the fly leaf radially outwards removes along the barrel, when the trace inwards shrink, drives the fly leaf radially inwards removes along the barrel.
A further improvement is that the spring constant of the second spring is 10 to 12 times that of the second spring.
The further improvement is that at least three second springs are uniformly arranged along the bottom of the mounting groove, and the bottom of the movable plate is provided with jacks corresponding to each second spring.
The further improvement is that a group of opposite guide rails are arranged in the mounting groove, both ends of the movable plate are movably connected to the guide rails, and a through groove is formed in one guide rail and used for penetrating the linkage rod.
The further improvement is that the linkage rod is formed by integrating an axial rod and a radial rod, the axial rod is fixedly connected with the movable plate, and the radial rod extends outwards along the radial direction of the cylinder body.
The further improvement is that the tail end of the linkage rod is provided with a spherical groove, and a rolling ball is movably embedded in the spherical groove.
The rolling ball is further improved in that the rolling ball is made of silicon nitride materials, and the inner surface of the ball-shaped groove is covered with a silicon nitride coating.
A further improvement is that the side of the scraper plate is provided with a bolt fixing.
The invention has the beneficial effects that: when the sleeve is scraped, no matter how the actual inner diameter of the sleeve is changed, the scraper plate can scrape with almost constant extrusion force, so that the conditions of damage to the scraper and clamping of a drilling tool caused by overlarge scraping force can be avoided, and the condition of poor cleaning effect caused by overlarge scraping force can be avoided.
Drawings
FIG. 1 is a schematic diagram of the overall structure of the present invention;
FIG. 2 is a cross-sectional view of a portion of the structure of the present invention;
FIG. 3 is a schematic diagram of the connection of the guide rail to the movable plate;
In the figure: 1. a cylinder; 2. a mounting groove; 3. a first spring; 4. a doctor plate; 5. a second spring; 6. a movable plate; 7. a linkage rod; 8. a jack; 9. a guide rail; 10. a through groove; 11. a spherical groove; 12. a rolling ball; 13. and a bolt fixing member.
Detailed Description
The present application will be described in further detail with reference to the accompanying drawings, wherein it is to be understood that the following detailed description is for the purpose of further illustrating the application only and is not to be construed as limiting the scope of the application, as various insubstantial modifications and adaptations of the application to those skilled in the art can be made in light of the foregoing disclosure.
Referring to fig. 1 to 3, a synchronous rotary drill bit scraper comprises a barrel 1, wherein a plurality of mounting grooves 2 are formed in the wall of the barrel 1, scraper plates 4 are connected in the mounting grooves 2 through first springs 3, and the scraper plates 4 extend out of the side edges of the barrel 1 and are used for scraping and cleaning the inner wall of a sleeve. The doctor plate 4 is provided with bolt mounts 13 at its sides for mounting and dismounting the doctor plate 4.
The mounting groove 2 is also internally provided with a second spring 5 with an elastic coefficient far larger than that of the first spring 3, the specific elastic coefficient of the second spring 5 is 10 to 12 times that of the second spring 5, and when the second spring is subjected to the action of the same force, the deformation amount of the first spring 3 is 10 to 12 times that of the second spring 5. The second springs 5 are at least three evenly arranged along the bottom of the mounting groove 2, the bottom of the movable plate 6 is provided with jacks 8 corresponding to each second spring 5, and the stability of the movable plate 6 is ensured due to the support of the plurality of second springs 5.
The top end of the second spring 5 is provided with a movable plate 6, the bottom of the first spring 3 is arranged on the movable plate 6, one end of the movable plate 6 is connected with a linkage rod 7, and the tail end of the linkage rod 7 extends out of the cylinder body 1. In order to ensure that the movable plate 6 can stably move, a group of opposite guide rails 9 are arranged in the mounting groove 2, two ends of the movable plate 6 are movably connected to the guide rails 9, and a through groove 10 is formed in the guide rail 9 at one end of the movable plate for penetrating through the linkage rod 7. The width of the through groove 10 is equal to the width of the penetrating part of the linkage rod 7, and the length of the through groove 10 is larger than the thickness of the penetrating part of the linkage rod 7, so that the linkage rod 7 can radially move back and forth.
In normal shaving, the compression of the first spring 3 is 2-3cm, and the compression of the second spring 5 by the same force is about 2mm, and this causes the first spring 3 to deform by about 2mm due to the stacked structure, and this changes the pressing force of the first spring 3 with a small spring constant to a negligible extent.
The linkage rod 7 is formed by an axial rod and a radial rod in an integrated mode, the axial rod passes through the through groove 10 and is fixedly connected with the movable plate 6, and the radial rod extends outwards along the radial direction of the cylinder body 1. The wall of the cylinder 1 is internally provided with a space for the linkage rod 7 to extend outwards or shrink inwards, when the linkage rod 7 extends outwards, the movable plate 6 moves outwards along the radial direction of the cylinder 1, and when the linkage rod 7 shrinks inwards, the movable plate 6 is driven to move inwards along the radial direction of the cylinder 1.
The tail end of the linkage rod 7 is provided with a spherical groove 11, the inner surface of the spherical groove 11 is covered with a layer of silicon nitride coating, the spherical groove 11 is movably embedded with a rolling ball 12, and the rolling ball 12 is made of silicon nitride material. The expansion coefficient of the silicon nitride material is small, and the locking phenomenon can not occur in the spherical groove 11 at high temperature; in addition, the silicon nitride material has extremely high hardness, excellent wear resistance and lubricity, so that the rolling ball 12 can stably rotate in a poor environment. The rolling ball 12 is arranged, so that under the condition that the elastic coefficient of the second spring 5 is larger, the linkage rod 7 can still move freely against the inner wall of the sleeve, and the rotation and the up-and-down movement of the scraper cannot be influenced.
When the invention is used, the scraper is arranged behind the drill bit and synchronously rotates with the drill bit, and the scraper and the drill bit are fed into the well together. During the feeding process, the rolling ball 12 at the tail end of the linkage rod 7 is in rolling contact with the inner wall of the sleeve. When a certain section of sediment on the inner wall of the sleeve is thicker, the thickness of the sediment reaches more than 3cm, which is equivalent to the radius of the sleeve being reduced by more than 3cm, if the traditional pipe scraper is adopted, the extrusion force of the first spring 3 is obviously greatly increased, the damage of the scraper and even the blocking of a drilling tool are easily caused; the inner wall of the sleeve can force the linkage rod 7 to move radially inwards to drive the movable plate 6 to move radially inwards along the guide rail 9, and the second spring 5 is compressed, so that the distance between the movable plate 6 and the inner wall of the sleeve is almost unchanged, the extrusion force of the first spring 3 is almost unchanged at the moment, the scraping is equivalent to scraping with normal extrusion force, thicker sediment can be thinned a little by each scraping, and the thicker sediment can be completely cleaned after a plurality of times of scraping, and the conditions of damage of a scraper and locking of a drilling tool can be effectively avoided by a plurality of times of scraping. When a certain section of the inner wall of the sleeve is severely eroded by drilling fluid, the inner diameter of the sleeve is enlarged, and if the sleeve is a traditional pipe scraper, the extrusion force of the first spring 3 is obviously reduced, and the scraping effect is reduced; by using the invention, the inner diameter of the sleeve is increased to enable the linkage rod 7 to correspondingly extend outwards, the movable plate 6 can radially move outwards under the elastic action of the second spring 5, and the distance between the movable plate 6 and the inner wall of the sleeve can be kept almost unchanged, so that the first spring 3 provides sufficient extrusion force to ensure scraping and cleaning effects.
The foregoing examples illustrate only a few embodiments of the invention and are described in detail herein without thereby limiting the scope of the invention. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the invention, which are all within the scope of the invention.