Coiled tubing hydraulic mechanical cutting anti-blocking process

Abstract

A continuous oil pipe hydraulic mechanical cutting anti-blocking process belongs to the technical field of oil field underground operation and comprises the following steps: S1, optimizing a cutting construction anti-blocking process; and S2, a cutting anti-blocking matching tool is developed. The continuous oil pipe cutting process is safe and reliable to use and operate, matched tools are easy to machine and manufacture, high in reliability, convenient to disassemble and maintain and low in investment fund, the cutting success rate reaches 100% through multiple times of field tests, the effect is obvious, the continuous oil pipe cutting process is accepted by field constructors and technicians, and the problem that in the lifting process of the 1.5-inch continuous oil pipe, the cutting efficiency is high is solved. The problem that the tool string is blocked due to the fact that an anchor for cutting the tool string is opened in advance and the like is solved, the success rate of tubular column blocking in continuous oil pipe hydraulic mechanical cutting is increased, meanwhile, the problems that conventional construction is high in risk, long in construction period and high in well repairing cost are solved, cutting of the tubular column blocking can be efficiently and rapidly achieved, and the working efficiency is improved. The overhaul operation is promoted to improve quality and speed, and rapid and efficient recovery of the oil-water well is realized.

Description

Technical Field

[0001] This invention belongs to the field of oilfield downhole operation technology, specifically relating to a hydraulic mechanical cutting anti-jamming process for coiled tubing. Background Technology

[0002] Currently, stuck tubing strings, such as those buried in sand or those unable to be released from the original packer, require extensive workovers involving unblocking, milling, backing, and retrieval. This process is risky, time-consuming, and costly. Therefore, we have researched a 1.5-inch coiled tubing hydraulic mechanical cutting technology. This technology uses coiled tubing to deliver a string of internal cutting tools, including a hydraulic cutter, screw motor, and hydraulic anchor, to the designed cutting position. First, the tubing anchor anchors the inner wall of the tubing. The increase in fluid flow starts the screw motor, causing it to rotate at high speed. This drives the cutter to rotate at the stuck position. Due to the pressure difference, the piston inside the cutter pushes the blades out, and the rotation causes the three blades to cut into the tubing wall. Repeated rotation cuts the tubing string.

[0003] However, during use, the anchor claws of the anchor suddenly open during the cutting of 1.5-inch coiled tubing, prematurely anchoring to the inner wall of the stuck tubing. This prevents the cutting tool string from continuing to descend or be retrieved, resulting in retrieval failure or even preventing the cutting string from being retrieved. If the lifting load is increased, the coiled tubing often breaks, causing a quality accident. In addition, after the coiled tubing is cut, the prestress of the tubing disappears or the tubing rebounds at the moment of cutting, often causing the anchor claws of the anchor to be unable to retract and become stuck, resulting in cutting failure. Summary of the Invention

[0004] To address the aforementioned problems, this invention proposes a hydraulic mechanical cutting anti-jamming process for coiled tubing, comprising the following steps:

[0005] S1. Optimize the anti-jamming process during cutting operations;

[0006] S2. Develop cutting and anti-jamming tools.

[0007] Step S1 includes the following steps:

[0008] S11. Before the coiled tubing is inserted into the well, the prestressing force of the stuck tubing string will be increased by 3 to 5 tons.

[0009] S12, Coiled tubing wellbore;

[0010] S13. Repeatedly perform well flushing operations down to below the cutting point. Before construction, conduct another cutting test on the ground with the cutting tool string to understand and record the relevant parameters of each tool's opening and resetting sequence, pressure displacement, and pump pressure.

[0011] S14. First, increase the displacement to the working displacement of the hydraulic anchor, then press down the coiled tubing to apply drilling pressure of 10kN-15kN to the hydraulic anchor. After confirming that the anchor is in place, gradually increase the displacement to the working displacement of the cutter to start cutting.

[0012] In step S12, the coiled tubing is circulated through the well: the coiled tubing string assembly is Ф38.1mm coiled tubing + Φ54mm connector + Φ54mm well gauge, with a displacement Q of 170L / min, and the outlet pressure is controlled not to exceed 1MPa. The coiled tubing is lowered to the target position, the coiled tubing depth is confirmed, and a mark is made on the roller of the coiled tubing unit.

[0013] The process also includes the following steps: S15. Start with a low displacement of 50 liters. Begin with the small displacement pump truck in second gear without shifting gears. Do not shift gears or stop the machine during the cutting process. Maintain a stable pumping position and inject liquid. Starting with a displacement of 50 liters, increase the displacement by 5 liters / min every 3 minutes, gradually increasing it to 70 liters. Then, cut at displacements of 70 liters, 80 liters, 90 liters, and 100 liters in sequence. The cutting process lasts for 10 minutes. Finally, increase the displacement to 110 liters. During the entire cutting process, do not stop the pump or shift gears until the oil pipe is surging or the cutting is stable for 20 minutes before stopping the pump.

[0014] The process also includes the following steps: S16, judging the cutting situation and pulling up the tubing after confirming successful cutting; observing the change in tubing suspension weight, which decreases after tubing suspension due to pre-tension; observing the amount of fluid returning from the tubing, which decreases after fluid enters the annulus after successful tubing cutting; and observing the change in pump pressure, which decreases after successful tubing cutting as the blade is no longer under pressure.

[0015] It also includes the following steps: S17. After the cutting is completed, the pump should be stopped and the pipe string should be raised to confirm that the hydraulic anchor has been released.

[0016] It also includes the following steps: S18, raising the cutting tool: stop the pump, and at the same time control the speed <5m / min to slowly raise the continuous tubing. Pay attention to the change in the suspended weight. If no jamming is found, raise the tubing normally at a speed ≤15m / min. Raise it out of the wellhead, check the wear of the tool handle, and determine the specific cutting situation.

[0017] Step S2 includes the following steps:

[0018] S21. Develop a hydraulic anchor anti-jamming balancing valve;

[0019] S22. Develop hydraulic anchor anti-jamming and centralizing device;

[0020] S23. Develop and manufacture anti-jamming safety connector assemblies;

[0021] S24, uses a low-speed, high-torque ∮54mm screw motor.

[0022] Step S21 includes the following steps: A ∮54mm hydraulic anchor balance valve is designed for continuous tubing cutting and installed between the hydraulic anchor and the screw motor. After the pump stops, it balances the pressure difference inside and outside the tubing to prevent the hydraulic anchor claws from opening due to the pressure difference inside and outside the tubing, which would make it difficult to raise and lower the cutting string. The bypass hole of the hydraulic anchor balance valve is normally open. When the pump starts and the discharge reaches 60 liters / minute, the balance valve hole closes without affecting the cutting operation. After the cutting operation is completed, the bypass hole of the hydraulic anchor balance valve automatically opens after the pump stops to balance the pressure difference inside and outside the tubing and allow the tubing string to be raised and lowered normally.

[0023] Step S22 includes the following steps: A ∮54mm hydraulic anchor anti-jamming stabilizer was designed for continuous tubing cutting. This tool is connected to the hydraulic anchor, and various loads are applied to the stabilizer. The groove of the stabilizer body does not affect the cutting flow rate, thus solving the problem of jamming caused by uneven force on the anchor teeth of the hydraulic anchor due to well inclination and other reasons.

[0024] Step S23 includes the following steps: After the cutting tool string gets stuck, first insert a ∮16mm steel ball, and through the safety connector, apply pressure of 18-25MPa to cut off the safety pin of the bypass valve. The bypass valve opens, creating an annular channel between the 1.5-inch continuous tubing and the 27 / 8-inch tubing, relieving the liquid column pressure inside the continuous tubing, reducing the pressure difference between the inside and outside of the continuous tubing and the tubing string. Under the pressure of the return spring, the anchor claw of the anchor is retracted, solving the problem of the anchor claw getting stuck and improving the cutting success rate of the continuous tubing.

[0025] In step S23, if the anchor claws of the anchor cannot be unstuck and retrieved, a ∮21mm steel ball is inserted again to apply pressure of 18-25MPa to cut the safety pin of the safety joint, and the coiled tubing in the well is removed, thus effectively handling the jamming of the cutting tool string.

[0026] Step S24 includes the following steps: Select a low-speed, high-torque ∮54mm screw motor with an outer diameter of 54mm, a length of 3.5m, an output speed of 270-680r / min, an output torque of 400N.m, an allowable drilling pressure of 24KN, and a maximum operating temperature of 150℃.

[0027] The beneficial effects of this invention are as follows: Currently, the problem of tool string jamming in coiled tubing cutting in China includes issues such as anchor teeth not being retracted, cutter blades getting stuck in the tubing, and ineffective handling of jamming. This invention solves the problem of premature opening of the anchor teeth in the cutting tool string, causing tool string jamming. Firstly, during the cutting process, the liquid column formed by the residual liquid inside the coiled tubing opens the anchor teeth of the tool string's anchor teeth, causing premature anchoring and jamming. Secondly, after cutting, the liquid column inside the tubing can be promptly removed, ensuring timely retraction of the anchor teeth and preventing anchor tooth jamming, which leads to a coiled tubing cutting success rate of less than 50%. Therefore, by optimizing the coiled tubing cutting construction process and improving the supporting auxiliary tools, the success rate of 1.5-inch coiled tubing cutting can reach over 90%.

[0028] This invention provides a safe and reliable coiled tubing cutting process. The accompanying tools are simple to manufacture, highly reliable, easy to disassemble and maintain, and require minimal investment. After multiple field tests, the cutting success rate reached 100%, demonstrating significant effectiveness and gaining recognition from on-site construction and technical personnel. It solves the problem of tool string jamming caused by premature opening of the anchor in the cutting tool string during the tripping of 1.5-inch coiled tubing, thus improving the success rate of hydraulic mechanical cutting of coiled tubing when encountering stuck tubing strings. At the same time, this process addresses the issues of high risk, long construction cycle, and high well workover costs associated with conventional construction methods. It enables efficient and rapid cutting of stuck tubing strings, promoting faster and better workover operations and facilitating rapid and efficient resumption of production in oil and water wells. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the hydraulic anchor anti-jamming balance valve structure of the present invention;

[0030] Figure 2 This is a schematic diagram of the hydraulic anchor anti-jamming stabilizer structure of the present invention;

[0031] Figure 3 This is a schematic diagram of the anti-jamming safety connector assembly of the present invention.

[0032] 1-First upper connector, 2-Nozzle, 3-Fixed housing, 4-Piston, 5-Reset spring, 6-First lower connector, 7-First O-ring seal, 8-Second O-ring seal, 9-First U-ring seal, 10-Second U-ring seal, 11-Third O-ring seal, 12-Second upper connector, 13-First housing, 14-One-way valve, 15-Connecting cylinder, 16-Second housing, 17-Steel ball, 18-First shear pin, 19-Lower piston, 20-Second shear pin, 21-Second lower connector, 22-Rupture disc, 23-Third upper connector, 24-Straightening block, 25-Third lower connector. Detailed Implementation

[0033] To make the technical means and objectives of this invention easier to understand, the invention is further described below with reference to specific embodiments. A hydraulic mechanical cutting anti-jamming process for coiled tubing includes the following steps:

[0034] S1. Optimize the anti-jamming process during cutting operations;

[0035] S2. Develop cutting and anti-jamming tools.

[0036] S1. Optimize the anti-jamming process during cutting. The 1.5-inch coiled tubing cutting tool string assembly, construction process, and parameters were optimized, along with pre-construction preparations. In terms of specific cutting operations, the optimized operation of the high-pressure, low-displacement pump ensured a cutting success rate of over 90%.

[0037] S11. Before the coiled tubing is inserted into the well, the tubing string needs to be prestressed by 3 to 5 tons.

[0038] S12. Coiled tubing well cleaning. Tubing string assembly: Ф38.1mm coiled tubing + Φ54mm connector + Φ54mm well gauge. Q: 170L / min, control the outlet pressure not to exceed 1MPa, lower the coiled tubing to the target position, confirm the coiled tubing depth, and mark it on the rollers of the coiled tubing unit.

[0039] S13. Repeatedly flush the well down to below the cutting point. Before construction, perform another cutting test on the ground with the cutting tool string to understand and record the opening and resetting sequence of each tool, pressure displacement, pump pressure and other relevant parameters.

[0040] S14. First, increase the displacement to the working displacement of the hydraulic anchor, then press down the coiled tubing to apply drilling pressure of 10kN-15kN to the hydraulic anchor. After confirming that the anchor is in place, gradually increase the displacement to the working displacement of the cutter to start cutting.

[0041] S15. Start with a low displacement of 50 liters. Begin with the small displacement pump truck in second gear without shifting gears. Do not shift gears or stop the machine during the cutting process; maintain a stable pumping position. Increase the displacement by 5 liters / min every 3 minutes until it reaches 70 liters. Then, proceed with cutting at displacements of 70 liters, 80 liters, 90 liters, and 100 liters, continuing for 10 minutes. Finally, increase the displacement to 110 liters. Do not stop the pump or shift gears during the entire cutting process until the oil pipe starts to bulge or the cutting is stable for 20 minutes before stopping the pump.

[0042] S16. Assess the cutting situation and pull up the tubing after confirming successful cutting. Observe the change in tubing weight. Due to the pre-tension, the tubing weight decreases after the tubing string is cut. Observe the amount of fluid returning from the tubing. After successful tubing string cutting, the fluid enters the annulus, and the amount of fluid returning from the tubing decreases. Observe the change in pump pressure. After successful tubing string cutting, the blade is no longer under pressure, and the pump pressure drops.

[0043] S17. After cutting is completed, the pump should be stopped and the pipe string should be raised for trial lifting. After confirming that the hydraulic anchor has been released, the pipe string can be raised.

[0044] S18. Retrieve cutting tool: Stop the pump and simultaneously control the speed to <5m / min to slowly retrieve the coiled tubing. Pay attention to changes in the suspended weight. If no jamming is found, retrieve the tubing normally at a speed of ≤15m / min. Retrieve the tool from the wellhead and check the wear of the tool handle to determine the specific cutting situation.

[0045] S2. Develop cutting and anti-jamming tools.

[0046] S21. Develop a hydraulic anchor anti-jamming balancing valve.

[0047] like Figure 1 As shown, a ∮54mm hydraulic anchor balancing valve was designed for continuous tubing cutting. This tool consists of a first upper connector, nozzle, fixed housing, piston, return spring, first lower connector, O-ring, and U-ring. Key parameters: outer diameter 54mm, minimum inner diameter 6mm, length 530mm, bypass port closing flow rate ≥60L / min. This tool is installed between the hydraulic anchor and the screw motor to balance the pressure difference inside and outside the tubing after pump shutdown, preventing the hydraulic anchor claws from opening due to the pressure difference, which would make it difficult to raise or lower the tubing string. The bypass port of the hydraulic anchor balancing valve is normally open. After pump startup, when the flow rate reaches 60 liters / minute, the valve orifice closes without affecting the cutting operation. After the cutting operation is completed, the bypass port of the hydraulic anchor balancing valve automatically opens after pump shutdown to balance the pressure difference inside and outside the tubing, allowing for normal tubing string raising and lowering.

[0048] S22. Develop hydraulic anchor anti-jamming and centralizing device.

[0049] like Figure 2 As shown, the tool consists of a third upper connector, a centralizing body, a third lower connector, and an O-ring. A ∮54mm hydraulic anchor balancing valve was designed for coiled tubing cutting. Due to well inclination, part of the coiled tubing's weight acts on the anchor teeth, causing incomplete anchoring during cutting, resulting in vertical movement, cutting failure, and premature damage to the cutter blade. Furthermore, the eccentricity of the cutting tool and the weight of the coiled tubing act on the anchor teeth, causing deformation and jamming between the anchor teeth and the outer cylinder of the anchor, preventing the anchor claws from being retrieved. This tool connects to the hydraulic anchor, transferring various loads to the centralizer. The groove in the centralizing body does not affect the cutting flow rate, thus solving the problem of jamming caused by uneven force on the hydraulic anchor teeth due to well inclination.

[0050] S23. Develop and manufacture anti-jamming safety connector assemblies.

[0051] like Figure 3As shown, this anti-jamming safety connector is mainly used when the cutting tool string gets stuck. First, a ∮16mm steel ball is inserted, and through the safety connector, a pressure of 18-25MPa is applied to shear the safety pin of the bypass valve. The bypass valve opens, establishing a channel between the 1.5-inch coiled tubing and the 27 / 8-inch tubing. This relieves the hydraulic pressure inside the coiled tubing, reducing the pressure difference between the inside and outside of the coiled tubing and the tubing string. Under the pressure of the return spring, the anchor claw of the anchor is retracted, resolving the anchor claw jamming problem and improving the success rate of coiled tubing cutting. If the jamming still cannot be resolved and the anchor claw of the anchor is not retracted, a ∮21mm steel ball is inserted again, and a pressure of 18-25MPa is applied to shear the safety pin of the safety connector, allowing the coiled tubing in the well to be removed. This effectively handles situations where the cutting tool string gets stuck.

[0052] S24, uses a low-speed, high-torque ∮54mm screw motor.

[0053] It uses a low-speed, high-torque ∮54mm screw motor with an outer diameter of 54mm and a length of 3.5m; the output speed is 270-680r / min, the output torque is 400N.m, the allowable drilling pressure is 24KN, and the maximum operating temperature is 150℃.

[0054] The purpose of this invention is to solve the problem of stuck tubing string during hydraulic mechanical cutting of a 1.5-inch coiled tubing in a certain well.

[0055] Tubing string structure: 1.5-inch continuous tubing + 1.5-inch anchored connector + ∮54mm anti-jamming safety joint + ∮54mm anti-jamming balance valve + ∮54mm hydraulic anchor + ∮54mm screw motor + ∮54mm anti-jamming centralizer + ∮54mm cutter;

[0056] Construction process of this invention: The Φ73mm thickened tubing became stuck. After repeated lifting and lowering attempts to release the jam at 500kN, the jamming did not resolve. The construction objective was to lower the cutting tool to the 2700m position and precisely cut the stuck 27 / 8" tubing. Construction process: The continuous tubing cutting string was lowered to 2700m. The pump truck was started in second gear without shifting gears. The pump pressure increased from 9.3MPa to 15.7MPa, the pump truck speed increased from 750r / min to 1150r / min, the displacement increased from 70L to 115L, and the cutting time was 40 minutes. Water returned from the casing, and the pump pressure dropped, indicating that the stuck tubing string had been successfully cut.

[0057] By optimizing the construction process and improving the supporting tools, the problems of anchor teeth getting stuck and not being retracted, and the cutting blade getting stuck during the continuous tubing cutting process, which caused cutting failures, were solved. By solving how to effectively handle the jamming during the cutting process, the success rate of continuous tubing cutting was greatly improved.

[0058] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A coiled tubing hydromechanical cutting anti-jamming process, characterized in that, It comprises the following steps: S1, optimizing the cutting construction anti-sticking process; S2, developing cutting anti-sticking matching tools.

2. The coiled tubing hydraulic mechanical cut-and- catch prevention process of claim 1, wherein, In the step S1, it comprises the following steps: S11, before the coiled tubing goes into the well, the stuck pipe column is pulled up with a pre-tension of 3-5 tons; S12, the coiled tubing goes into the well; S13, the washing well operation is repeatedly carried out to the cutting point below, before the construction, the cutting tool string is cut again on the ground to understand and record the sequence of opening and resetting of each tool, the relevant parameters of pressure displacement and pump pressure; S14, the displacement is first increased to the working displacement of the hydraulic anchor, then the coiled tubing is pressed to add a drilling pressure of 10-15 kN to the hydraulic anchor, after the anchoring is judged, the displacement is gradually increased to the working displacement of the cutter to start cutting.

3. The coiled tubing hydraulic mechanical cutting anti-jab process of claim 2, wherein, In the step S12, the coiled tubing goes into the well: the coiled tubing column combination is Φ38.1 mm coiled tubing + Φ54 mm connector + Φ54 mm well-passing rule, the displacement Q is 170 L / min, the control outlet pressure is not more than 1 MPa, the coiled tubing is lowered to the target position, the coiled tubing depth is confirmed, and a mark is made on the drum of the coiled tubing truck.

4. The coiled tubing hydraulic mechanical cut-and- catch prevention process of claim 2, wherein, It further comprises the following step: S15, starting with a low displacement of 50 liters, starting with a small displacement pump truck in the second gear without shifting, the cutting process cannot be shifted and cannot be stopped, and a gear must be kept stable to pump liquid; the displacement is increased by 5 liters / min every 3 minutes starting from 50 liters, gradually increasing to 70 liters, and then the cutting displacement is 70 liters, 80 liters, 90 liters, 100 liters, cutting lasts for 10 minutes, and finally the displacement is increased to 110 liters, the pump is not allowed to stop or shift during the entire cutting process, until the tubing is up or the cutting is stable for 20 minutes.

5. The coiled tubing hydraulic mechanical cut-and- catch prevention process of claim 4, wherein, It further comprises the following step: S16, judging the cutting condition and confirming the success of cutting; observing the change of tubing hanging weight, due to the pre-tension, the tubing hanging weight decreases after the column is cut; observing the amount of liquid returned from the tubing, after the column is cut successfully, fluid enters the annulus, and the amount of liquid returned from the tubing decreases; observing the change of pump pressure, after the column is cut successfully, the blades are not strained, and the pump pressure decreases.

6. The coiled tubing hydraulic mechanical cut-and- catch prevention process of claim 5, wherein, It further comprises the following step: S17, after the cutting is completed, the pump should be stopped first, and after confirming that the hydraulic anchor is unanchored, the column is lifted.

7. The coiled tubing hydraulic mechanical cut-and- catch prevention process of claim 6, wherein, It further comprises the following step: S18, lifting the cutting tool: stopping the pump, and controlling the speed to be less than 5 m / min to slowly lift the coiled tubing, and observing the change of hanging weight, if no sticking phenomenon is found, the tubing is normally lifted at a speed of ≤15 m / min; the wellhead is lifted, the tool is checked for cutter handle wear, and the cutting condition is determined.

8. The coiled tubing hydraulic mechanical cutting anti-jab process of claim 1, wherein, In the step S2, it comprises the following steps: S21, developing a hydraulic anchor anti-sticking balance valve; S22, developing a hydraulic anchor anti-sticking centralizer; S23, developing an anti-sticking safety joint assembly; S24, applying a low-speed high-torque ∮54 mm screw motor.

9. The coiled tubing hydraulic mechanical cutting anti-jab process of claim 8, wherein, The step S21 comprises the following steps: a coiled tubing cutting hydraulic anchor balance valve with a diameter of 54 mm is designed and installed between the hydraulic anchor and the screw motor to balance the pressure difference between the inside and outside of the balance pipe after the pump is stopped, prevent the hydraulic anchor from opening the anchor jaw due to the pressure difference between the inside and outside of the pipe, cause the cutting pipe column to be difficult to be lifted, and keep the bypass hole of the hydraulic anchor balance valve in an open state at all times. When the displacement reaches 60 liters per minute after the pump is started, the through hole of the balance valve is closed, does not affect the cutting operation, and after the cutting operation is completed, the bypass hole of the hydraulic anchor balance valve is automatically opened after the pump is stopped to balance the pressure difference between the inside and outside of the pipe and normally lift the pipe column.

10. The coiled tubing hydraulic mechanical cutting anti-jab process of claim 8, wherein, The step S22 comprises the following steps: a coiled tubing cutting hydraulic anchor anti-stuck centralizer with a diameter of 54 mm is designed and connected to the hydraulic anchor. Various loads are applied to the centralizer, and the groove of the centralizer body does not affect the cutting displacement, thereby solving the problem of the anchor tooth of the hydraulic anchor being unevenly stressed and causing sticking due to well inclination and other reasons.

11. The coiled tubing hydraulic mechanical cutting anti-jab process of claim 8, wherein, The step S23 comprises the following steps: after the cutting tool string is stuck, a steel ball with a diameter of 16 mm is first put in, a safety joint is pressed at 18-25 MPa to shear the safety pin of the bypass valve, the bypass valve is opened, a channel is established between the 1.5-inch coiled tubing and the 27 / 8-inch pipe annulus, the liquid column pressure in the coiled tubing is unloaded, the pressure difference between the inside and outside of the coiled tubing and the pipe column is reduced, the anchor jaw of the anchor is retracted under the pressure of the reset spring, the anchor jaw of the anchor is stuck, the success rate of the coiled tubing cutting is improved.

12. The coiled tubing hydraulic mechanical cut-and- catch prevention process of claim 11, wherein, In the step S23, if the anchor jaw of the anchor cannot be stuck and recovered, a steel ball with a diameter of 21 mm is put in again, the safety joint is pressed at 18-25 MPa to shear the safety pin, the coiled tubing in the well is taken out, and effective treatment is realized after the cutting tool string is stuck.

13. The coiled tubing hydraulic mechanical cutting anti-jab process of claim 8, wherein, The step S24 comprises the following steps: a low-speed high-torque 54 mm screw motor is selected, the outer diameter is 54 mm, the length is 3.5 m, the output speed is 270-680 r / min, the output torque is 400 N.m, the allowable drilling pressure is 24 KN, and the highest use temperature is 150 DEG C.

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