Device and process for derusting inner wall of oil pipe by adopting coiled tubing

Abstract

The invention relates to the technical field of rust removal of the inner wall of an oil pipe, in particular to a device and a process for removing rust on the inner wall of the oil pipe by adopting a continuous oil pipe, which are used for solving the problem that the rust of the pipe can only be cleaned on the ground on the site at present. The continuous scraping and cutting module comprises an arc-shaped scraping and cutting gear, and a fixed shaft rotates in the middle of the lower connector. One end of the double-end gear shaft is connected with a bevel gear, the other end of the double-end gear shaft is connected with a straight spur gear, and an inner gear ring is connected in the third upper connector; the process comprises the following steps: acquiring parameter information of a construction well; well entering simulation; compiling a derusting construction design; tools required by rust removal are prepared; finishing a working site; derusting the inner wall of the oil pipe; when the continuous scraping and cutting module is put into an oil pipe, the straight scraping and cutting gear is attached to the inner wall of the oil pipe to roll and drives the double-end gear shaft to rotate, the third upper connector and the third lower connector rotate relatively, and therefore the straight scraping and cutting gear and the arc-shaped scraping and cutting gear conduct scraping and cutting around the inner wall of the oil pipe.

Description

Technical Field

[0001] The present invention relates to the technical field of rust removal for the inner wall of oil pipes, and particularly to a device and process for removing rust from the inner wall of oil pipes using coiled tubing. Background Art

[0002] In the process of petroleum engineering operations, various pipes such as casings, oil pipes, and drill pipes are tools that are often used on-site, and some pipes need to be reused. However, during use and storage, the surface of the pipes will oxidize and rust. The main reasons are as follows: during the tripping operation in the use process, repeated friction causes the anti-rust layer on the surface of the pipes to fall off, losing its protective effect, resulting in oxidation of the pipes in the air; long-term immersion in high-temperature and high-pressure kill fluids causes the anti-rust layers on the inner and outer surfaces of the pipes to corrode and fall off, resulting in oxidation reactions; during storage, improper maintenance causes rust on the inner and outer surfaces of the pipes.

[0003] In order to ensure the construction quality at the operation site, it is necessary to perform rust removal operations on the inner wall of the pipe string that has been lowered into the well. Currently, on-site, only the pipes can be cleaned of rust on the ground. Generally, a pipe gauge is used in combination with a sledgehammer to remove rust, which has high labor intensity, slow operation efficiency, and poor cleaning effect. Therefore, there is an urgent need for a tool and process that can remove rust from the oil pipes that have been lowered into the well to ensure high-efficiency and high-quality completion of construction operations at the operation site. Summary of the Invention

[0004] The present invention provides a device for removing rust from the inner wall of an oil pipe using coiled tubing and a process for removing rust from the inner wall of an oil pipe to solve the problem that currently, only the pipes can be cleaned of rust on the ground at the operation site.

[0005] In order to alleviate the above technical problems, the technical solution provided by the present invention lies in:

[0006] A device for removing rust from the inner wall of an oil pipe using a coiled tubing, comprising: an equal-diameter connection joint connected to the end of the coiled tubing; a continuous scraping module connected to the equal-diameter connection head; the continuous scraping module includes: a third upper joint; a third lower joint rotatably fixed at the lower part of the third upper joint; a straight scraping gear rotatably fixed within the third lower joint; a driving gear rotatably fixed within the third lower joint and meshing with the straight scraping gear; a double-headed gear shaft rotatably fixed within the third upper joint and the third lower joint, and the axis of the double-headed gear shaft is parallel to the axes of the third upper joint and the third lower joint; an arc scraping gear rotatably fixed in the middle of the lower joint; one end of the double-headed gear shaft is connected with a bevel gear meshing with the driving gear, the other end of the double-headed gear shaft is connected with a spur cylindrical gear, and an internal gear ring meshing with the spur cylindrical gear is connected within the third upper joint; when the continuous scraping module is lowered into the oil pipe, the straight scraping gear rolls along the inner wall of the oil pipe and drives the double-headed gear shaft to rotate, so that the third upper joint and the third lower joint rotate relative to each other, and thus the straight scraping gear and the arc scraping gear scrape around the inner wall of the oil pipe.

[0007] Furthermore, it further includes: a check valve connected to the equal-diameter connection joint; a safety joint connected to the check valve; a rotating precision brush module connected to the safety joint; the rotating precision brush module includes: a second upper joint connected to the safety joint; a central tube integrally provided with the second upper joint and in a cylindrical shape; a second lower joint connected to the bottom of the central tube; a precision brush barrel sleeved on the central tube; the precision brush barrel includes: a barrel body; bristles connected to the outer wall of the barrel body; two annular grooves opened on the outer wall of the barrel body; a universal air bubble nozzle connected to one of the annular grooves; a directional impact nozzle connected to the other annular groove; an oval through hole opened on the side wall of the central tube and communicating with the universal air bubble nozzle and the directional impact nozzle; a part of the liquid in the coiled tubing passes through the check valve, then enters the central tube through the safety joint, enters the annular groove of the barrel body through the oval through hole on the central tube, and is ejected to the inner wall of the oil pipe through the universal air bubble nozzle, and at the same time, a reverse force is generated when ejected from the directional impact nozzle to drive the precision brush barrel to rotate, so that the bristles scrape the inner wall of the oil pipe.

[0008] Furthermore, it further includes: a pulse rust removal module connected to the rotary precision brush module; the pulse rust removal module includes: a fourth upper joint connected to the third lower joint and having a diversion cavity formed inside; a vane type diversion wheel rotatably disposed in the diversion cavity inside the fourth upper joint; a spherical spray head connected to the fourth upper joint; a diversion inclined hole is formed on the fourth upper joint; an interactive liquid passing hole is formed inside the spherical spray head, a side liquid discharge hole is formed on the side wall of the spherical spray head, and a bottom liquid discharge hole is formed at the bottom of the spherical spray head; when the other part of the liquid in the coiled tubing passes through the diversion inclined hole, an oblique impact force is generated to impact the vane type diversion wheel to rotate at a high speed, and the rotating vane type diversion wheel intermittently blocks the interactive liquid passing hole, so that the liquid intermittently enters the interactive liquid passing hole and is pulsed out from the side liquid discharge hole and the bottom liquid discharge hole to the inner wall of the tubing respectively.

[0009] Furthermore, a diversion wheel shaft is connected in the diversion cavity of the upper joint, and the vane type diversion wheel rotates on the diversion wheel shaft.

[0010] A rust removal process for the inner wall of a tubing, the rust removal process uses a rust removal device, and includes the following steps:

[0011] S1. Obtain the parameter information of the construction well;

[0012] S2. Downhole simulation;

[0013] S3. Compile a rust removal construction design;

[0014] S4. Prepare the tools required for rust removal;

[0015] S5. Repair the operation site;

[0016] S6. Implement the rust removal work on the inner wall of the tubing.

[0017] Furthermore, step S4 further includes:

[0018] S41. Prepare a coiled tubing operation device with corresponding operation capacity according to the requirements of the rust removal construction design;

[0019] S42. Prepare well control devices such as a blowout preventer box, a blowout preventer pipe, a blowout preventer, etc. and a reducing flange matching the tubing hanger;

[0020] S43. Determine a lifting device according to the heights and maximum loads of the coiled tubing wellhead injection head, the blowout preventer box, the blowout preventer pipe, the blowout preventer, the wellhead production tree, etc.;

[0021] S44. The depth counter of the coiled tubing should be calibrated before operation;

[0022] S45. A chip catcher, a choke manifold and a surface filter should be prepared before operation;

[0023] S46. Prepare the pumping equipment and auxiliary devices according to the design requirements;

[0024] S47. Prepare sufficient liquid storage tanks, metering tanks, and waste liquid storage tanks according to the requirements of the operation construction;

[0025] S48. Prepare equal-diameter connection joints, rotary micrometer brush modules, continuous scraping modules, and pulsed derusting modules that meet the construction requirements;

[0026] S49. Prepare derusting working fluid and adhesive solution with performance and quantity meeting the requirements of the construction design. The resistance reduction rate of the derusting working fluid is not less than 40%, and the viscosity of the adhesive solution is not less than 40 mPa·S.

[0027] Furthermore, step S6 further includes:

[0028] S61. Equipment placement, installation, and pressure testing;

[0029] S62. Connect the tool string;

[0030] S63. Derusting construction.

[0031] Furthermore, step S61 further includes:

[0032] S611. The placement, installation, and pressure testing of the coiled tubing equipment shall meet the requirements of relevant standards;

[0033] S612. Connect the pumping equipment, surface high-pressure filter, and coiled tubing reel in sequence and conduct pressure testing according to the well control design until qualified;

[0034] S613. Install a debris catcher, choke manifold, recovery pipeline, and liquid storage tank outward from the casing gate in sequence and conduct pressure testing according to the well control design until qualified.

[0035] Furthermore, step S62 further includes:

[0036] S621. Flush the coiled tubing with the working medium until the liquid properties at the inlet and outlet ends are consistent, conduct a ball test, and then connect the equal-diameter connection joint to the free end of the coiled tubing;

[0037] S622. Connect the pressure testing pull plate to conduct a load test on the connector, gradually increase the pulling force, and the pulling force shall be greater than the release working load of the safety joint. The connector is qualified if there is no slip;

[0038] S623. Conduct overall pressure testing on the inlet pipeline, coiled tubing, equal-diameter connection joint, etc. The pressure testing shall meet the requirements of the construction design;

[0039] S624. Connect the equal-diameter connection joint, check valve, safety joint, rotary micrometer brush module, continuous scraping module, and pulsed derusting module in sequence from top to bottom;

[0040] S625. Start the pumping equipment, debug the performance of each tool in the tool string at different displacement rates, observe the working conditions of each tool, and do not allow the tool string to enter the well if it does not meet the requirements;

[0041] S626. Connect the blowout preventer pipe to the wellhead blowout preventer, and conduct a pressure test on the overall blowout prevention device above the master valve of the tubing head. The pressure test should meet the requirements of the construction design.

[0042] Furthermore, step S63 also includes:

[0043] S631. Clear the counter, record the position where the bottom end of the tool string is located when cleared, open the wellhead main valve, and lower the coiled tubing;

[0044] S632. Slowly lower the coiled tubing;

[0045] S633. During the normal lowering process, conduct a pull-up and lowering test every 300 m and record the data. Start the pump circulation from when the tool enters the well, and the return displacement should be 0.40 m3 / min to 0.45 m3 / min;

[0046] S634. If there is resistance during the process, the applied pressure shall not exceed 20 kN. Record the depth of the resistance position and the hook load value at the actual exploration of the resistance position, and then slowly pull up and lower the coiled tubing tool string at a speed not greater than 10 m / min to 5 m / min for activity rust removal;

[0047] S635. After rust removal is completed, circulate and wash the well for more than 1.5 rounds, and pull up the coiled tubing to the wellhead;

[0048] S636. Confirm that the tool string has completely entered the blowout preventer pipe, and close the wellhead main valve;

[0049] S637. Confirm that the wellhead main valve is completely closed, relieve the pressure of the blowout preventer pipe, remove and discard the drilling and grinding tool, and remove all equipment at the wellhead.

[0050] The beneficial effects of the present invention are analyzed as follows:

[0051] A device for removing rust from the inner wall of an oil pipe using a coiled tubing, comprising an equal-diameter connecting joint connected to the end of the coiled tubing; a continuous scraping module connected to the equal-diameter connector; the continuous scraping module includes: a third upper joint; a third lower joint rotatably fixed at the lower part of the third upper joint; a straight scraping gear rotatably fixed within the third lower joint; a driving gear rotatably fixed within the third lower joint and meshing with the straight scraping gear; a double-headed gear shaft rotatably fixed within the third upper joint and the third lower joint, and the axis of the double-headed gear shaft is parallel to the axes of the third upper joint and the third lower joint; an arc scraping gear rotatably fixed in the middle of the lower joint; one end of the double-headed gear shaft is connected with a bevel gear meshing with the driving gear, the other end of the double-headed gear shaft is connected with a spur cylindrical gear, and an internal gear ring meshing with the spur cylindrical gear is connected within the third upper joint.

[0052] The straight scraping gear and the arc scraping gear of the continuous scraping module bite into the inner wall of the pipe string. When lowering, the straight scraping gear rotates around its center under the action of the biting force, and at the same time drives the driving gear to rotate. The bevel gears of the double-headed gear shaft and the driving gear mesh with each other. Therefore, driven by the driving gear, through the transmission and change of the transmission direction of the double-headed gear shaft, the third lower joint rotates along the internal gear ring of the third upper joint, ensuring that the scraping of the inner wall of the pipe string by the straight scraping gear and the arc scraping gear is carried out without dead angles of 360 degrees. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the related art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the related art. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0054] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0055] Figure 2 It is a full-sectional structure schematic diagram of the equal-diameter connecting joint of the present invention;

[0056] Figure 3 It is a structural schematic diagram of the coiled tubing connecting core pipe of the present invention;

[0057] Figure 4 It is a half-sectional structure schematic diagram of the coiled tubing joint housing of the present invention;

[0058] Figure 5 It is a half-sectional and top-view structure schematic diagram of the coiled tubing joint sliding tapered slip of the present invention;

[0059] Figure 6Schematic diagram of the half-section and top view of the wedge slider of the coiled tubing joint of the present invention;

[0060] Figure 7 Schematic diagram of the half-section structure of the rotary micrometer brush module of the present invention;

[0061] Figure 8 Schematic diagram of the half-section structure of the central tube of the present invention;

[0062] Figure 9 Schematic diagram of the half-section structure of the micrometer brush barrel of the present invention;

[0063] Figure 10 Schematic diagram of the full-section and top view of the universal cavitation nozzle of the present invention;

[0064] Figure 11 Schematic diagram of the full-section and top view of the directional impact nozzle of the present invention;

[0065] Figure 12 Schematic diagram of the half-section and top view of the spacer ring of the present invention;

[0066] Figure 13 Schematic diagram of the structure at the second lower joint of the present invention;

[0067] Figure 14 Schematic diagram of the full-section structure of the continuous scraping module of the present invention;

[0068] Figure 15 For the present invention Figure 14 Schematic diagram of the structure of A-A in;

[0069] Figure 16 For the present invention Figure 14 Schematic diagram of the structure of B-B in;

[0070] Figure 17 For the present invention Figure 14 Schematic diagram of the structure of C-C in;

[0071] Figure 18 For the present invention Figure 14 Schematic diagram of the structure of D-D in;

[0072] Figure 19 Schematic diagram of the structure of the third upper joint of the present invention;

[0073] Figure 20 Schematic diagram of the full-section and top view of the double-headed gear shaft of the present invention;

[0074] Figure 21 Schematic diagram of the full-section and left view of the driving gear of the present invention;

[0075] Figure 22 Schematic diagram of the full-section and left view of the arc-shaped scraping gear of the present invention;

[0076] Figure 23 Full-sectional and top-view structural schematic diagrams of the movable bushing of the present invention;

[0077] Figure 24 Full-sectional structural schematic diagram of the third lower joint of the present invention;

[0078] Figure 25 Full-sectional structural schematic diagram of the pulse rust-removing head of the present invention;

[0079] Figure 26 For the present invention Figure 25 Structural schematic diagram of E-E in;

[0080] Figure 27 For the present invention Figure 25 Structural schematic diagram of F-F in;

[0081] Figure 28 Full-sectional and top-view structural schematic diagrams of the fourth upper joint of the present invention;

[0082] Figure 29 Full-sectional and top-view structural schematic diagrams of the vane-type flow guide wheel of the present invention;

[0083] Figure 30 Full-sectional and top-view structural schematic diagrams of the spherical spray head of the present invention.

[0084] Icon:

[0085] 100. Equal-diameter connection joint; 110. Coiled tubing connection core tube; 111. Sealing section; 120. Joint housing; 121. Serrated structure; 122. Screw hole; 130. Coiled tubing joint sliding tapered slip; 131. Small serrated structure; 132. Large serrated structure; 140. Coiled tubing joint wedge-shaped slider; 150. First lower joint; 200. Rotary micrometer brush module; 210. Second upper joint; 220. Central tube; 221. Oval through-hole; 230. Micrometer brush barrel; 231. Barrel body; 2311. Directional nozzle seat; 2312. Universal nozzle seat; 232. Brush bristles; 233. Universal cavitation nozzle; 234. Directional impact nozzle; 240. Spacer ring; 250. Second lower joint; 300. Continuous scraping module; 310. Third upper joint; 311. Inner support of connecting bearing; 312. Inner gear ring; 320. Double-headed gear shaft; 330. Driving gear; 340. Straight scraping gear; 350. Arc-shaped scraping gear; 360. Support spring; 370. Movable bushing; 380. Rotating shaft; 390. Third lower joint; 391. Outer support of connecting bearing; 392. Mounting seat; 393. First scraping gear seat; 394. Second scraping gear seat; 395. Spiral central hole passage; 400. Pulse rust removal module; 410. Fourth upper joint; 411. Internal thread at the upper end; 412. Internal diversion inclined hole; 413. Diversion cavity; 414. Diversion wheel shaft; 415. External thread at the lower end; 420. Vane-type diversion wheel; 430. Spherical injection head; 431. Upper-end thread; 432. Interactive liquid passage hole; 433. Diversion wheel groove; 434. Internal partition layer; 435. Side liquid discharge hole; 436. Bottom liquid discharge hole. Detailed implementation manner

[0086] The technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0087] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. In addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0088] In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "installation", "connection", and "coupling" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0089] Embodiment 1

[0090] As Figures 1 - 30 shown, a device for removing rust from the inner wall of an oil pipe using a coiled tubing includes: an equal-diameter connection joint 100 connected to the end of the coiled tubing; a continuous scraping module 300 connected to the equal-diameter connection head; the continuous scraping module 300 includes: a third upper joint 310; a third lower joint 390 rotatably fixed at the lower part of the third upper joint 310; a straight scraping gear 340 rotatably fixed in the third lower joint 390; a driving gear 330 rotatably fixed in the third lower joint 390 and meshing with the straight scraping gear 340; a double-headed gear shaft 320 rotatably fixed in the third upper joint 310 and the third lower joint 390, and the axis of the double-headed gear shaft 320 is parallel to the axes of the third upper joint 310 and the third lower joint 390; an arc scraping gear 350 rotatably fixed in the middle of the lower joint; one end of the double-headed gear shaft 320 is connected with a bevel gear meshing with the driving gear 330, the other end of the double-headed gear shaft 320 is connected with a straight cylindrical gear, and an internal gear ring 312 meshing with the straight cylindrical gear is connected in the third upper joint 310; when the continuous scraping module 300 is lowered into the oil pipe, the straight scraping gear 340 rolls while fitting on the inner wall of the oil pipe and drives the double-headed gear shaft 320 to rotate, so that the third upper joint 310 and the third lower joint 390 rotate relative to each other, and thus the straight scraping gear 340 and the arc scraping gear 350 scrape around the inner wall of the oil pipe.

[0091] The working mechanism of the rust removal device provided in this embodiment:

[0092] The straight scraping gear 340 and the arc scraping gear 350 of the continuous scraping module 300 bite into the inner wall of the pipe string. When lowering, the straight scraping gear 340 rotates around its center under the action of the biting force, and at the same time drives the driving gear 330 to rotate. The bevel gears of the double-headed gear shaft 320 mesh with the bevel gears of the driving gear 330. Therefore, under the drive of the driving gear 330, through the transmission and change of the transmission direction by the double-headed gear shaft 320, the third lower joint 390 rotates along the internal gear ring 312 of the third upper joint 310, ensuring that the scraping of the inner wall of the pipe string by the straight scraping gear 340 and the arc scraping gear 350 is carried out without dead angles for 360 degrees;

[0093] The third upper joint 310 is of a cylindrical structure. An internal thread that mates with the second lower joint 250 is machined at the upper end. The lower end is a connecting bearing inner support 311. A connecting bearing that is jointly borne by the upper outer support of the third lower joint 390 is provided. An internal gear ring 312 that mates with the upper spur gear of the double-headed gear shaft 320 is machined at the end near the connecting bearing inner support 311 inside the third upper joint 310. The double-headed gear shaft 320 is of a dumbbell-shaped columnar structure. One end is a spur cylindrical gear that mates with the internal gear ring 312 of the third upper joint 310. The other end is a bevel gear that mates with the driving gear 330. The middle part is a fixed shaft that fixes the double-headed gear shaft 320 on the fixed seat of the third lower joint 390. The driving gear 330 is of a flat cylindrical structure with a central through hole. A bevel gear is machined at one end to mate with the bevel gear of the double-headed gear shaft 320. A spur gear is machined on the outer wall at the other end to mate with the straight scraping gear 340. The straight scraping gear 340 is of a chess-piece-like structure with a central through hole. A spur gear is machined at its edge to mate with the spur gear of the driving gear 330. At the same time, the spur gear at the edge, under the action of the support spring 360, closely adheres to the inner wall of the pipe column and bites into the rust layer, and uses the hardness of the spur gear to cut and scrape the rust scale on the inner wall of the pipe column. The arc-shaped scraping gear 350 is similar to the straight scraping gear 340, except that an arc surface that fits the inner wall of the pipe column is machined at its edge to ensure closer fitting during cutting and scraping and improve the rust removal effect. The support spring 360 is a spring with a certain elastic force. One end is fixed on the spring seat, and the other end is fixed on the movable bushing 370 of the straight scraping gear 340, enabling the straight scraping gear 340 to move within a certain range under the action of the support spring 360 and providing a certain elastic force for the straight scraping gear 340 to bite into the inner wall of the pipe column. The movable bushing 370 is of a racket shape. A shaft hole that mates with the rotating shaft 380 is machined at the center of its racket net. The length and diameter at the racket handle can be machined according to the inner diameter of the support spring 360 to ensure that the support spring 360 can be sleeved. The rotating shaft 380 is of a cylindrical structure. Its length should ensure that it passes through the central through hole of the straight scraping gear 340 and the central through holes of the two movable bushings 370 at the same time, and snap spring grooves are machined at both ends for placing limit snap springs. The third lower joint 390 is of a cylindrical structure and mainly includes a connecting bearing outer support 391, a mounting seat 392, a first scraping gear seat 393, a second scraping gear seat 394, a spiral central channel 395, and a lower connecting thread. A step for placing a bearing is machined at the uppermost end of the third lower joint 390 for the connecting bearing outer support 391, and it is mated and fixedly connected with the connecting bearing inner support 311 of the third upper joint 310 to fix the connecting bearing, enabling the third upper joint 310 and the third lower joint 390 to rotate relative to each other. The mounting seat 392 is a groove for placing the driving gear 330 machined in the inner cavity of the third lower joint 390, and a pin hole is machined at the position corresponding to the central axis of the driving gear 330. The size of the groove ensures that the driving gear 330 can rotate freely.The inner end of the first scraping gear seat 393 communicates with the mounting seat 392, and the outer end penetrates through the body. Its width can be determined according to the width of the straight scraping gear 340. Grooves in the shape of rounded rectangles are machined on the two side walls at the central axis position. The height thereof is equal to the diameter of the central axis of the straight scraping gear 340, and the width is greater than the diameter of the central axis of the straight scraping gear 340 to ensure that the central axis moves within the rounded rectangle grooves. A columnar groove for placing the support spring 360 and a base for fixing the spring are machined on one side. The second scraping gear seat 394 is similar to the first scraping gear seat 393. The difference is that the first scraping gear seat 393 only has a columnar groove for the support spring 360 on one side, while the second scraping gear seat 394 has columnar grooves on both sides. The spiral central channel 395 is formed by machining a number of spiral through holes inside the third lower joint 390 to ensure the normal flow of liquid. The number and diameter thereof can be determined according to the space inside the third lower joint 390. The lower connecting thread is a male thread connected to the fourth upper joint 410.

[0094] Regarding the structure of the rotary precision ruler brush module 200, specifically:

[0095] It further includes: a check valve connected to the equal-diameter connection joint 100; a safety joint connected to the check valve; a rotary precision ruler brush module 200 connected to the safety joint; the rotary precision ruler brush module 200 includes: a second upper joint 210 connected to the safety joint; a central tube 220 integrally provided with the second upper joint 210 and in a cylindrical shape; a second lower joint 250 connected to the bottom of the central tube 220; a precision ruler brush cylinder 230 sleeved on the central tube 220; the precision ruler brush cylinder 230 includes: a cylinder body 231; bristles 232 connected to the outer wall of the cylinder body 231; two annular grooves opened on the outer wall of the cylinder body 231; a universal cavitation nozzle 233 connected to one of the annular grooves; a directional impact nozzle 234 connected to the other annular groove; an oval through hole 221 opened on the side wall of the central tube 220 and communicating with the universal cavitation nozzle 233 and the directional impact nozzle 234; a part of the liquid in the coiled tubing passes through the check valve, then enters the central tube 220 through the safety joint, enters the annular groove of the cylinder body 231 through the oval through hole 221 on the central tube 220, and is ejected to the inner wall of the tubing through the universal cavitation nozzle 233. At the same time, it is ejected from the directional impact nozzle 234 to generate a reverse force to drive the rotation of the precision ruler brush cylinder 230, so that the bristles 232 scrape the inner wall of the tubing.

[0096] The coiled tubing connection mandrel 110 is a cylinder with a variable outer diameter. The coiled tubing and the joint housing 120 are respectively sleeved on the coiled tubing connection mandrel 110. The coiled tubing joint sliding tapered slip 130 is located in the cavity between the coiled tubing and the joint housing 120 and clamps the two together. The coiled tubing joint wedge-shaped slider 140 is located between the joint housing 120 and the coiled tubing connection mandrel 110. One end of the coiled tubing joint wedge-shaped slider 140 is wedged into the wedge slot between the coiled tubing and the coiled tubing connection mandrel 110, and the other end of the coiled tubing joint wedge-shaped slider 140 abuts against the joint coiled tubing screw inserted into the joint housing 120. The upper coiled tubing connection mandrel 110 is a cylindrical structure, and a sealing section 111 with an outer diameter slightly larger than the inner diameter of the coiled tubing is machined on the outer wall of its left end. The coiled tubing and the sealing section 111 of the coiled tubing connection mandrel 110 are in interference fit. Six annular sealing grooves and three pressing grooves are machined on the sealing section 111 of the coiled tubing connection mandrel 110. Three annular sealing grooves and three pressing grooves are alternately distributed from the left end to the right end of the sealing section 111, and the other three annular sealing grooves are continuously distributed; the middle part of the coiled tubing connection mandrel 110 is a groove, and the outer diameter of the groove is the same as the inner diameter of the coiled tubing cutting body of the coiled tubing; the right end of the coiled tubing connection mandrel 110 is a cylinder larger than the outer diameter of the groove. Two annular sealing grooves are machined at the left end of the cylinder for installing O-rings, and external threads are machined at the right end of the cylinder. The outer diameter of the joint housing 120 is the same as the outer diameter of the equal-diameter connection joint 100 and the two are coaxial. A serrated structure 121 is machined on the inner wall of the left end of the joint housing 120; the middle part of the inner wall of the joint housing 120 is a groove, and a first-stage and a second-stage step are machined on the right side of the groove. Looking from left to right, the inner diameter of the first-stage step is smaller than the inner diameter of the groove and is a cylindrical surface. A screw hole 122 is machined at the left end of the first-stage step for installing the upper joint coiled tubing screw; the inner diameter of the second-stage step is smaller than the inner diameter of the first-stage step, and internal threads are machined on the inner wall of the second-stage step, and the internal threads are matched with the external threads on the outer wall of the coiled tubing connection mandrel 110. The coiled tubing joint sliding tapered slip 130 is a cylindrical structure. A small serrated structure 131 is machined on the inner wall of the coiled tubing joint sliding tapered slip 130, and a large serrated structure 132 opposite to the small serrated structure 131 is machined on the outer wall of the coiled tubing joint sliding tapered slip 130; the coiled tubing joint sliding tapered slip 130 is located inside the cavity between the joint housing 120 and the coiled tubing, and the large serrated structure 132 on the outer wall of the coiled tubing joint sliding tapered slip 130 is matched with the serrated structure 121 on the inner wall of the left end of the joint housing 120;The small serrated structure 131 on the inner wall of the coiled tubing joint sliding tapered slip 130 clamps tightly against the outer wall of the coiled tubing cutting body, increasing the frictional resistance between the coiled tubing connector and the coiled tubing cutting body. The inner diameter of the coiled tubing joint wedge-shaped slider 140 is the same as the outer diameter at the groove of the upper coiled tubing connection core pipe 110. The left end outer wall of the upper coiled tubing joint wedge-shaped slider 140 is machined into a tapered surface with a smaller left outer diameter and a larger right outer diameter, and the right end outer wall of the upper coiled tubing joint wedge-shaped slider 140 is a cylindrical surface. The coiled tubing joint wedge-shaped slider 140 is formed by combining two half-rings with the same structure. One end of the half-ring is a double clamping structure, and the other end is a single clamping structure. The single clamping structure of one half-ring engages with the double clamping structure of the other half-ring to form an integral coiled tubing joint wedge-shaped slider 140, which is located at the middle position between the joint housing 120 and the coiled tubing connection core pipe 110. The right end of the coiled tubing joint wedge-shaped slider 140 abuts against the coiled tubing joint screw. The left end of the coiled tubing joint wedge-shaped slider 140 is wedged between the coiled tubing and the coiled tubing connection core pipe 110. The coiled tubing joint wedge-shaped slider 140 provides an extrusion force for the end of the coiled tubing. The first lower joint 150 is machined with a male thread at the lower end to connect with the second upper joint 210;

[0097] The second upper joint 210 is processed with internal threads at the upper part of the rotary precision ruler brush module 200 to cooperate with the first lower joint 150. The central tube 220 and the second upper joint 210 are of an integral hollow cylindrical structure. That is, a limiting step is processed at the lower part of the second upper joint 210 to limit the precision ruler brush cylinder 230, and the diameter of the part below the limiting step is smaller than the inner diameter of the precision ruler brush cylinder 230. Oval through holes 221 are opened at positions corresponding to the nozzles on the precision ruler brush cylinder 230 to make it communicate inside and outside. External threads matching the second lower joint 250 are processed at the lowermost end of the central tube 220. The precision ruler brush cylinders 230 are sleeved on the central tube 220 in groups of two with a spacer ring 240 in between. It mainly consists of a cylinder body 231, bristles 232, a universal cavitation nozzle 233 and a directional impact nozzle 234. The cylinder body 231 is a cylindrical structure with a certain thickness and length, and its inner diameter is slightly larger than the outer diameter of the central tube 220. Two annular concave grooves with a rectangular cross-section are processed at positions on its inner wall corresponding to the through holes of the central tube 220. Four through directional nozzle seats 2311 with a certain angle are evenly arranged in the circumferential direction of the upper groove among them for installing the directional impact nozzle 234. Four universal nozzle seats 2312 are evenly arranged in the circumferential direction of the lower groove for installing the universal cavitation nozzle. The bristles 232 are short steel wires with a certain length embedded in the part of the outer wall of the cylinder body 231 where there are no universal cavitation nozzles and directional impact nozzles 234, so that they are embedded in the outer wall of the cylinder body 231 for a certain length and exposed for a certain length, making them arranged in a spiral shape. There is a certain gap between each row for the flow of the liquid containing iron filings to avoid pressure buildup and blockage. The universal cavitation nozzle 233 is spherical with a limiting shoulder, and a through hole with a certain angle is processed inside the spherical center perpendicular to the limiting shoulder. The directional impact nozzle 234 is flat cylindrical, and a flared through hole with a large end and a small end is processed inside. The spacer ring 240 is a ring with a certain thickness and width sleeved on the central tube 220, and its inner diameter is larger than the outer diameter of the central tube 220, and its outer diameter is the same as the outer diameter of the steel body of the precision ruler brush cylinder 230. The upper part of the second lower joint 250 has internal threads connected to the central tube 220, and the lower part has male threads connected to the third upper joint 310.

[0098] Regarding the structure of the pulsed rust removal module 400, specifically:

[0099] It further includes: a pulse rust removal module 400, connected to the rotary close scale brush module 200; the pulse rust removal module 400 includes: a fourth upper joint 410, connected to the third lower joint 390 and having a diversion cavity 413 formed therein; a vane type diversion wheel 420, rotatably disposed in the diversion cavity 413 inside the fourth upper joint 410; a spherical spray head 430, connected to the fourth upper joint 410; a diversion inclined hole is formed on the fourth upper joint 410; an interactive liquid passage hole 432 is formed inside the spherical spray head 430, a side liquid discharge hole 435 is formed on the side wall of the spherical spray head 430, and a bottom liquid discharge hole 436 is formed at the bottom of the spherical spray head 430; when another part of the liquid in the coiled tubing passes through the diversion inclined hole, an oblique impact force is generated to impact the vane type diversion wheel 420 to rotate at a high speed, and the rotating vane diversion wheel intermittently blocks the interactive liquid passage hole 432, so that the liquid intermittently enters the interactive liquid passage hole 432 and is pulsed out from the side liquid discharge hole 435 and the bottom liquid discharge hole 436 to the inner wall of the tubing respectively.

[0100] The fourth upper joint 410 is of a cylindrical structure and mainly consists of an internal thread 411 at the upper end, a diversion inclined hole 412 inside, a diversion cavity 413, a diversion wheel shaft 414, and an external thread 415 at the lower end. The internal thread 411 at the upper end is an internal thread machined at the upper end of the fourth upper joint 410 to cooperate with the third lower joint 390. The diversion inclined hole 412 inside is a number of through square holes with a certain slope arranged in a circular pattern machined on the bottom plane of the internal thread 411 at the upper end inside the fourth upper joint 410, enabling the liquid to enter the diversion cavity 413 through the inclined holes at a certain injection angle. The diversion cavity 413 is an annular cavity with a certain depth machined inside the lower end of the fourth upper joint 410, and its size can be determined according to the size of the vane-type diversion wheel 420 to ensure that the vane-type diversion wheel 420 rotates freely inside it, while the bottom is connected to the diversion inclined hole 412 inside. The diversion wheel shaft 414 is a shaft left in the center inside the diversion cavity 413 for fixing the vane-type diversion wheel 420, and its diameter can be determined according to the central shaft hole of the vane-type diversion wheel 420. The external thread 415 at the lower end is an external thread machined on the outer wall of the other end of the fourth upper joint 410 to cooperate with the upper-end thread 431 of the spherical injection head 430. The vane-type diversion wheel 420 is a structure with a number of blades at a certain angle and a central shaft hole, and is a flat columnar shape with a certain thickness, and a central shaft hole is machined in its center and sleeved on the diversion wheel shaft 414 to ensure free rotation. The spherical injection head 430 is of a hemispherical structure and mainly has an upper-end thread 431, an alternating liquid-passing hole 432, a diversion wheel groove 433, an internal partition 434, a side liquid-draining hole 435, and a bottom liquid-draining hole 436. The upper-end thread 431 is an internal thread machined on the upper part of the spherical injection head 430 to cooperate with the external thread 415 at the lower end. The alternating liquid-passing hole 432 is a number of through holes arranged in a circular pattern machined inside the spherical injection head 430, and two adjacent through holes lead to the side liquid-draining hole 435 and the bottom liquid-draining hole 436 respectively. When the vane-type diversion wheel 420 rotates, it will periodically block the alternating liquid-passing hole 432, generating a pulsed shock wave. The diversion wheel groove 433 is a cylindrical groove machined at the central position of the alternating liquid-passing hole 432, and its diameter can be determined according to the size of the diversion wheel shaft 414. The internal partition 434 is a horizontal partition machined inside the spherical injection head 430 to separate the side liquid-draining hole 435 and the bottom liquid-draining hole 436 from each other. The side liquid-draining hole 435 is a number of communication holes machined on the side wall of the spherical injection head 430, and the inside is connected to a part of the alternating liquid-passing hole 432. The bottom liquid-draining hole 436 is a number of communication holes machined at the bottom semi-circle of the spherical injection head 430, and the inside is connected to another part of the alternating liquid-passing hole 432.

[0101] Embodiment 2

[0102] A rust-removing process for the inner wall of an oil pipe. This rust-removing process uses the rust-removing device in Embodiment 1 and includes the following steps:

[0103] S1. Obtain the parameter information of the construction well;

[0104] S2. Conduct downhole simulation;

[0105] S3. Compile the rust removal construction design;

[0106] S4. Prepare the tools required for rust removal;

[0107] S5. Trim the operation site;

[0108] S6. Implement the rust removal work on the inner wall of the tubing.

[0109] The parameter information of the construction well that needs to be obtained in step S1 includes: the type of the construction well, the casing specification, the casing damage situation, and the specification model of the Christmas tree; the well deviation data of the construction well; the formation pressure coefficient, temperature, and fluid properties; the current wellhead pressure, production capacity, and leakage situation; the original production interval, downhole debris, and previous operation measures; the current downhole string structure situation;

[0110] The specific downhole simulation in step S2 is as follows: According to parameters such as the wellbore structure, well deviation data, and production casing, conduct software simulation on the wellbore trajectory of the construction well; the input coiled tubing parameters should meet the requirements of SY / T6895, input the working fluid parameters and tool string data, conduct coiled tubing downhole simulation, and perform the following work according to the simulation results: When the simulation result shows that the coiled tubing can reach the bottom of the string, record the normal lowering and lifting hook loads; when the simulation result shows that the coiled tubing cannot reach the bottom of the string, add a hydraulic oscillator to the coiled tubing, or use a metal drag reducer, or use both at the same time, and conduct simulation until the simulation result shows that the coiled tubing can reach the bottom of the string, then record the normal lowering and lifting hook loads. If the result still shows that it cannot reach the bottom of the string, replace the coiled tubing with other sizes for simulation;

[0111] The compilation of the rust removal construction design in step S3 includes: Compile the coiled tubing rust removal construction design according to the well testing geological design, well testing engineering design, and downhole simulation results. The coiled tubing rust removal construction design should formulate detailed construction steps, operation requirements, material preparation, etc., and refine and improve the quality, well control, and environmental protection requirements; the coiled tubing rust removal construction design should be changed simultaneously with the changes in the well testing geological design and well testing engineering design;

[0112] The trimming of the operation site in step S5 includes: Survey the road entering the well site to ensure the smooth passage of coiled tubing construction vehicles; conduct well site leveling to ensure that it can bear the construction equipment and there is enough operation space around the wellhead; the operation site should have the conditions for blowout and testing and meet the requirements of blowout ignition.

[0113] Regarding the preparation of the tools required for rust removal in step S4, further includes:

[0114] S41. Prepare coiled tubing operation equipment with corresponding operation capacity according to the requirements of rust removal construction design;

[0115] S42. Prepare well control devices such as blowout preventer boxes, blowout preventer pipes, blowout preventers, etc., and reducing diameter flanges matching the tubing head;

[0116] S43. Determine the lifting equipment according to the heights and maximum loads of the coiled tubing wellhead injection head, blowout preventer box, blowout preventer pipe, blowout preventer, wellhead production tree, etc.;

[0117] S44. Calibrate the coiled tubing depth counter before operation;

[0118] S45. Prepare a chip catcher, choke manifold and surface filter before operation;

[0119] S46. Prepare the pump injection equipment and auxiliary devices according to the design requirements;

[0120] S47. Prepare sufficient liquid storage tanks, metering tanks and waste liquid storage tanks according to the requirements of the operation construction;

[0121] S48. Prepare equal-diameter connection joints 100, rotary density brush modules 200, continuous scraping modules 300 and pulsed rust removal modules 400 that meet the construction requirements;

[0122] S49. Prepare rust removal working fluid and glue with performance and quantity meeting the requirements of the construction design. The resistance reduction rate of the rust removal working fluid is not less than 40%, and the viscosity of the glue is not less than 40 mPa·S.

[0123] Regarding the implementation of rust removal work on the inner wall of the tubing in step S6, it further includes:

[0124] S61. Equipment placement, installation and pressure testing;

[0125] S62. Connect the tool string;

[0126] S63. Rust removal construction.

[0127] Regarding equipment placement, installation and pressure testing in step S61, it further includes:

[0128] S611. The placement, installation and pressure testing of the coiled tubing equipment shall meet the requirements of relevant standards;

[0129] S612. Connect the pump injection equipment, surface high-pressure filter and coiled tubing drum in sequence, and pass the pressure test according to the well control design;

[0130] S613. Install a chip catcher, choke manifold, recovery pipeline and liquid storage tank outward from the casing gate in sequence, and pass the pressure test according to the well control design.

[0131] Regarding the connection of the tool string in step S62, it further includes:

[0132] S621. Flush the coiled tubing with the working medium until the liquid properties at the inlet and outlet ends are consistent. Conduct a ball test, and then connect the equal-diameter connection joint 100 to the free end of the coiled tubing;

[0133] S622. Connect the pressure test pull disk to test the load of the connector. Gradually increase the pulling force, and the pulling force should be greater than the release working load of the safety joint. It is qualified if there is no slip of the connector;

[0134] S623. Conduct an overall pressure test on the inlet pipeline, coiled tubing, equal-diameter connection joint 100, etc. The pressure test should meet the requirements of the construction design;

[0135] S624. Connect the equal-diameter connection joint 100, check valve, safety joint, rotary density brush module 200, continuous scraping module 300, and pulsed derusting module 400 in sequence from top to bottom;

[0136] S625. Start the pumping equipment, debug the performance of each tool in the tool string at different displacements, observe the working conditions of each tool, and if it does not meet the requirements, the tool string is not allowed to enter the well;

[0137] S626. Connect the blowout preventer pipe to the wellhead blowout preventer, and conduct an overall pressure test on the blowout prevention device above the master valve of the tubing hanger. The pressure test should meet the requirements of the construction design.

[0138] Regarding the derusting construction in step S63, it further includes:

[0139] S631. Clear the counter, record the position where the bottom end of the tool string is located when clearing, open the main valve of the wellhead, and lower the coiled tubing;

[0140] S632. Slowly lower the coiled tubing;

[0141] S633. During the normal lowering process, conduct a lifting and lowering test every 300 m and record the data. Start the pump and circulate from the time the tool enters the well, and the return displacement should be 0.40 m3 / min to 0.45 m3 / min;

[0142] S634. If there is a blockage during the process, the applied pressure shall not exceed 20 kN. Record the depth of the blockage position and the hook load value at the actual exploration of the blockage position, and then slowly lift and lower the coiled tubing tool string at a speed not greater than 10 m / min to 5 m / min for derusting;

[0143] S635. After derusting is completed, circulate and wash the well for more than 1.5 rounds, and lift the coiled tubing to the wellhead;

[0144] S636. Confirm that the tool string has completely entered the blowout preventer pipe and close the main valve of the wellhead;

[0145] S637. Confirm that the main wellhead valve is fully closed, relieve the pressure of the blowout preventer pipe, remove and discard the drill grinding tool, and remove all equipment at the wellhead.

[0146] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A device for removing rust from the inner wall of a tubing using a coiled tubing, characterized in that ； it includes: an equal-diameter connecting joint (100) connected to the end of the coiled tubing; a continuous scraping module (300) connected to the equal-diameter connecting head; the continuous scraping module (300) includes: a third upper joint (310); a third lower joint (390) rotatably fixed about the lower part of the third upper joint (310); a straight scraping gear (340) rotatably fixed within the third lower joint (390); a driving gear (330) rotatably fixed within the third lower joint (390) and meshing with the straight scraping gear (340); a double-headed gear shaft (320) rotatably fixed within the third upper joint (310) and the third lower joint (390), and the axis of the double-headed gear shaft (320) is parallel to the axes of the third upper joint (310) and the third lower joint (390); an arc-shaped scraping gear (350) rotatably fixed at the middle of the lower joint; one end of the double-headed gear shaft (320) is connected with a bevel gear meshing with the driving gear (330), the other end of the double-headed gear shaft (320) is connected with a spur cylindrical gear, and an internal gear ring (312) meshing with the spur cylindrical gear is connected within the third upper joint (310); when the continuous scraping module (300) is lowered into the tubing, the straight scraping gear (340) rolls while fitting against the inner wall of the tubing and drives the double-headed gear shaft (320) to rotate, causing the third upper joint (310) and the third lower joint (390) to rotate relative to each other, so that the straight scraping gear (340) and the arc-shaped scraping gear (350) scrape around the inner wall of the tubing.

2. The device for removing rust from the inner wall of a tubing using a coiled tubing according to claim 1, characterized in that ； it further includes: a check valve connected to the equal-diameter connecting joint (100); a safety joint connected to the check valve; a rotating precision brush module (200) connected to the safety joint; the rotating precision brush module (200) includes: a second upper joint (210) connected to the safety joint; a central tube (220) integrally provided with the second upper joint (210) and in a tubular shape; a second lower joint (250) connected to the bottom of the central tube (220); a precision brush barrel (230) sleeved on the central tube (220); the precision brush barrel (230) includes: a barrel body (231); brush bristles (232) connected to the outer wall of the barrel body (231); two annular grooves opened on the outer wall of the barrel body (231); a universal cavitation nozzle (233) connected within one of the annular grooves; a directional impact nozzle (234) connected within the other annular groove; an oval through-hole (221) opened on the side wall of the central tube (220) and communicating with the universal cavitation nozzle (233) and the directional impact nozzle (234); A part of the liquid in the coiled tubing passes through the check valve and then enters the oval through-hole (221) on the central tube (220) through the safety joint, enters the annular groove of the cylinder body (231), and is ejected to the inner wall of the tubing through the universal cavitation nozzle (233). At the same time, it is ejected from the directional impact nozzle (234) to generate a reverse force to drive the micrometer brush cylinder (230) to rotate, so that the bristles (232) scrape the inner wall of the tubing.

3. The device for removing rust from the inner wall of a tubing using a coiled tubing according to claim 2, characterized in that ； it further comprises: a pulsed rust removal module (400), connected to the rotating micrometer brush module (200); the pulsed rust removal module (400) comprises: a fourth upper joint (410), connected to the third lower joint (390) and having a diversion cavity (413) opened therein; a vane type diversion wheel (420), rotating in the diversion cavity (413) inside the fourth upper joint (410); a spherical spray head (430), connected to the fourth upper joint (410); a diversion inclined hole is opened on the fourth upper joint (410); an interactive liquid passing hole (432) is opened inside the spherical spray head (430), a side liquid discharge hole (435) is opened on the side wall of the spherical spray head (430), and a bottom liquid discharge hole (436) is opened at the bottom of the spherical spray head (430); When another part of the liquid in the coiled tubing passes through the diversion inclined hole, it generates an oblique impact force to impact the vane type diversion wheel (420) to rotate at a high speed. The rotating vane type diversion wheel intermittently blocks the interactive liquid passing hole (432), so that the liquid intermittently enters the interactive liquid passing hole (432) and is pulsed out to the inner wall of the tubing from the side liquid discharge hole (435) and the bottom liquid discharge hole (436) respectively.

4. The device for removing rust from the inner wall of a tubing using a coiled tubing according to claim 3, characterized in that; a diversion wheel shaft (414) is connected in the diversion cavity (413) of the upper joint, and the vane type diversion wheel (420) rotates on the diversion wheel shaft (414).

5. A rust removal process for the inner wall of a tubing, the rust removal process using the rust removal device according to any one of claims 1-4, characterized in that it comprises the following steps: S1. Obtain the parameter information of the construction well; S2. Conduct in-well simulation; S3. Compile a rust removal construction design; S4. Prepare the tools required for rust removal; S5. Repair the operation site; S6. Implement the rust removal work on the inner wall of the tubing.

6. The rust removal process for the inner wall of a tubing according to claim 5, characterized in that ； step S4 further comprises: S41. Prepare a coiled tubing operation device with corresponding operation capacity according to the requirements of the rust removal construction design; S42. Prepare well control devices such as a blowout preventer box, a blowout preventer pipe, a blowout preventer, etc. and a reducing flange matching the tubing head; S43. Determine the lifting equipment according to the heights and maximum loads of the coiled tubing wellhead injection head, blowout preventer box, blowout preventer pipe, blowout preventer, wellhead production tree, etc.; S44. The depth counter of the coiled tubing should be calibrated before operation. S45. Before operation, a chip catcher, a choke manifold and a surface filter shall be prepared; S46. Prepare the pumping equipment and auxiliary devices according to the design requirements; S47. Prepare sufficient liquid storage tanks, metering tanks and waste liquid storage tanks according to the requirements of the operation construction; S48. Prepare equal-diameter connecting joints (100), rotary micrometer brush modules (200), continuous scraping modules (300) and pulsed derusting modules (400) that meet the construction requirements; S49. Prepare derusting working fluids and adhesive fluids with performance and quantity meeting the requirements of the construction design. The resistance reduction rate of the derusting working fluid shall not be less than 40%, and the viscosity of the adhesive fluid shall not be less than 40 mPa·S.

7. The derusting process for the inner wall of the tubing according to claim 5, characterized in that ； step S6 further includes: S61. Equipment placement, installation and pressure testing; S62. Connect the tool string; S63. Derusting construction.

8. The derusting process for the inner wall of the tubing according to claim 7, characterized in that ； step S61 further includes: S611. The placement, installation and pressure testing of the coiled tubing equipment shall meet the requirements of relevant standards; S612. Connect the pumping equipment, the surface high-pressure filter and the coiled tubing reel in sequence and conduct pressure testing according to the well control design to be qualified; S613. Install a chip catcher, a choke manifold, a recovery pipeline and a liquid storage tank outward from the casing gate in sequence and conduct pressure testing according to the well control design to be qualified.

9. The derusting process for the inner wall of the tubing according to claim 7, characterized in that ； step S62 further includes: S621. Flush the coiled tubing with the working medium until the liquid properties at the inlet and outlet ends are the same, conduct a ball passing test, and then connect the equal-diameter connecting joint (100) to the free end of the coiled tubing; S622. Connect a pressure testing pull disc to conduct a load test on the connector, gradually increase the pulling force, and the pulling force shall be greater than the release working load of the safety joint. It is qualified if the connector does not slip; S623. Conduct overall pressure testing on the inlet pipeline, the coiled tubing, the equal-diameter connecting joint (100), etc. The pressure testing shall meet the requirements of the construction design; S624. Connect the equal-diameter connecting joint (100), check valve, safety joint, rotary micrometer brush module (200), continuous scraping module (300) and pulsed derusting module (400) from top to bottom in sequence; S625. Start the pumping equipment, debug the performance of each tool in the tool string at different displacement rates, observe the working conditions of each tool, and do not allow the tool string to enter the well if it does not meet the requirements; S626. Connect the blowout preventer pipe to the wellhead blowout preventer and conduct overall pressure testing on the blowout prevention device above the master valve of the tubing head. The pressure testing shall meet the requirements of the construction design.

10. The derusting process for the inner wall of the tubing according to claim 7, characterized in that ； step S63 further includes: S631. Clear the counter, record the position where the bottom end of the tool string is located when clearing, open the wellhead main valve, and lower the coiled tubing; S632. Slowly lower the coiled tubing; S633. During the normal lowering process, conduct a up-and-down test every 300 m and record the data. Start the pump and circulate from the time the tool enters the well, and the return displacement rate shall be 0.40 m3 / min to 0.45 m3 / min; S634. If there is resistance during the process, the applied pressure shall not exceed 20 kN. Record the depth of the position where resistance is encountered and the hook load value during the actual exploration of the position where resistance is encountered. Then, slowly lift and lower the coiled tubing tool string at a speed not greater than 10 m / min to 5 m / min for activities to remove rust. S635. After rust removal is completed, circulate and wash the well for more than 1.5 rounds, and lift the coiled tubing to the wellhead. S636. Confirm that the tool string has completely entered the blowout preventer pipe and close the main wellhead valve. S637. Confirm that the main wellhead valve is completely closed, relieve the pressure of the blowout preventer pipe, remove and discard the drilling and grinding tool, and remove all equipment at the wellhead.

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