A motor for coiled tubing and method of use

Abstract

The application discloses a motor for coiled tubing and a use method thereof. The motor comprises an external shell and an internal transmission component installed in the external shell. The external shell is composed of a short section, a power shell, a winding shaft shell, a transmission shaft shell and an end sleeve which are sequentially screwed together. The internal transmission component is composed of a rotor, a winding shaft and a transmission shaft which are sequentially screwed together. A rubber stator corresponding to the rotor is fixedly installed in the power shell. An upper compensating sleeve is installed between the winding shaft shell and the winding shaft. A lower compensating sleeve is installed between the end sleeve and the transmission shaft. A roller bearing assembly and an oil bath type bearing assembly are respectively installed between the transmission shaft shell and the transmission shaft. The motor assembly is simultaneously increased with the stator and the rotor, so that the rotor outputs a lower rotating speed to the transmission shaft, thereby driving the fishing tool connected to the lower part of the transmission shaft to rotate and guiding the fish head into the fishing tool.

Description

Technical Field

[0001] This invention relates to a coiled tubing motor and its usage method, and more particularly to a coiled tubing motor used in horizontal wells and highly deviated wells, belonging to the field of oilfield downhole workover technology. Background Technology

[0002] In horizontal and highly deviated wells, conventional well tubing is subjected to a "pendulum force," resulting in a large friction area near the bottom edge of the wellbore. Consequently, the lifting force and torque at the wellhead cannot be effectively transmitted to the downhole horizontal section. Coiled tubing is flexible and can be easily run into the wellbore, but it cannot rotate, yet rotational power is required during drilling and workover operations.

[0003] A conventional screw motor is a high-torque, high-speed drilling screw motor. When combined with milling and cutting tools, if a conventional screw motor and bottom-hole tools are rotated together, the conventional screw motor's excessive speed often causes serious damage to bottom-hole tools such as grinding shoes and cutters, resulting in downhole accidents. Therefore, conventional screw motors are not suitable for horizontal wells and highly deviated wells. Summary of the Invention

[0004] The purpose of this invention is to provide a motor for coiled tubing and a method of using it, which can provide low-speed rotational power to coiled tubing to realize downhole coiled tubing milling and cutting operations, thereby overcoming the shortcomings of the prior art.

[0005] The technical solution of the present invention: A motor for continuous tubing includes an outer housing and an internal transmission component installed inside the outer housing. The outer housing is composed of a short section, a power housing, a shaft housing, a transmission shaft housing, and an end sleeve connected in sequence by threads. The internal transmission component is composed of a rotor, a shaft, and a transmission shaft connected in sequence by threads. A rubber stator corresponding to the rotor is fixedly installed inside the power housing. An upper mandrel sleeve is installed between the shaft housing and the shaft. A lower mandrel sleeve is installed between the end sleeve and the transmission shaft. A roller bearing assembly and an oil bath bearing assembly are respectively installed between the transmission shaft housing and the transmission shaft.

[0006] Furthermore, the outer wall of the rotor is provided with an outer helical groove, and the inner wall of the rubber stator is provided with an inner helical groove with the same pitch as the outer helical groove, and the outer helical groove and the inner helical groove are staggered.

[0007] Furthermore, a flow cavity is reserved between the upper part of the shaft, the power housing, and the shaft housing. A countersunk hole communicating with the central hole of the transmission shaft is provided in the lower part of the shaft, and a flow hole communicating with the flow cavity is provided on the side wall of the countersunk hole.

[0008] Furthermore, the roller bearing assembly includes an adjusting shim, a retaining ring, and a long shaft sleeve sequentially fitted onto the drive shaft. A set of first semicircular grooves is formed on the inner wall of the upper end of the long shaft sleeve, and a set of second semicircular grooves corresponding to the first semicircular grooves are formed on the external thread end face of the upper end of the drive shaft. The first semicircular grooves and the first semicircular grooves form a circular hole, and a pin that rolls in contact with the drive shaft is installed in each circular hole, with the end of the pin contacting the retaining ring.

[0009] Furthermore, the oil bath bearing assembly includes an annular boss on the inner wall of the drive shaft housing, and a long sleeve and a short sleeve fitted on the drive shaft. An oil injection hole is radially provided on the annular boss, and an oil plug is threaded into the oil injection hole. A set of connecting shafts is axially inserted into the annular boss, and two stop discs are symmetrically connected to both ends of the set of connecting shafts. A short sleeve is fitted on the drive shaft and between the two stop discs. An oil passage hole is provided at the lower end of the long sleeve. An oil sealing piston is fitted on the upper part of the long sleeve. A backlash ring is also fitted on the drive shaft and below the lower stop disc. A steel ball is embedded between the backlash ring and the drive shaft.

[0010] Furthermore, the oil sealing piston includes an inner sleeve fitted on a long shaft sleeve, and the upper end of the inner sleeve is slidably connected to a groove on the inner wall of the transmission shaft housing via a positioning key. A dustproof sealing ring A and a fifth sealing ring are respectively installed between the inner sleeve and the long shaft sleeve, and a fourth sealing ring is installed between the inner sleeve and the transmission shaft housing.

[0011] Furthermore, a wear-resistant pad is installed between the stop disc and the long shaft sleeve or the anti-reverse ring.

[0012] Meanwhile, the present invention also provides a method of using the motor for continuous tubing described above. First, high-pressure mud is introduced into the spiral groove between the rubber stator and the rotor. The high-pressure mud drives the rotor to rotate and outputs torque, which in turn drives the shaft and the transmission shaft to rotate together. At the same time, the upper mandrel sleeve on the shaft and the lower mandrel sleeve on the transmission shaft respectively perform eccentric compensation on the shaft and the transmission shaft, converting the eccentric rotation into fixed-axis rotation. Then, the torque is transmitted to the transmission shaft along the center line. Finally, the transmission shaft drives the grinding shoe or cutter at the end of the tool to perform grinding or cutting operations.

[0013] In the above method, the rubber stator and rotor constitute a hydraulic drive motor based on the monotro principle, and the hydraulic drive motor is provided with three or more stages.

[0014] The advantages of this invention due to the adoption of the above technical solution are as follows:

[0015] 1. The continuous tubing motor of the present invention has no bypass valve and universal joint, and its structure is simple and reasonable.

[0016] 2. The motor for coiled tubing of the present invention applies coiled tubing milling and cutting technologies, enabling operations that are difficult to achieve with conventional techniques. It can be applied to milling, reaming, cutting, sleeve milling, or any other operation that requires rotation of bottom hole tools.

[0017] 3. The continuous tubing motor of the present invention increases the number of stator and rotor heads in the motor assembly, so that the rotor outputs a lower speed to the drive shaft, thereby driving the retrieval tool connected to the lower part of the drive shaft to rotate, which can more easily guide the fish head into the retrieval tool. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of the present invention;

[0019] Figure 2 This is a schematic diagram of the structure of a roller bearing assembly;

[0020] Figure 3 This is a schematic diagram of the structure of an oil bath bearing assembly.

[0021] Explanation of reference numerals in the attached drawings: 1-Short section; 2-First sealing ring; 3-Stator; 4-Rotor; 5-Shaft; 6-Second sealing ring; 7-Shaft housing; 8-Third sealing ring; 9-Positioning key; 10-Inner sleeve; 11-Adjusting shim; 12-Retaining ring; 13-Dustproof sealing ring A; 14-Pin; 15-Fourth sealing ring; 16-Fifth sealing ring; 17-Long shaft sleeve; 18-Drive shaft housing; 19-Sixth sealing ring; 20-Wear-resistant pad ; 21-Stop plate; 22-Connecting shaft; 23-Oil plug; 24-Short shaft sleeve; 25-Anti-reverse ring; 26-Steel ball; 27-Seventh sealing ring; 28-End sleeve; 29-Wear-resistant ring; 30-Eighth sealing ring; 31-Dustproof sealing ring B; 32-Drive shaft; 33-Flow hole; 34-Power housing; 35-Upper mandrel sleeve; 36-Lower mandrel sleeve; 37-Flow cavity; 38-Counterhole; 39-Oil hole; 40-Annular boss. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0023] Embodiments of the present invention: See Figure 1The continuous tubing motor of the present invention includes an outer housing and an internal transmission component installed inside the outer housing. The outer housing is composed of a short section 1, a power housing 34, a shaft housing 7, a transmission shaft housing 18, and an end sleeve 28 connected together in sequence by threads. The internal transmission component is composed of a rotor 4, a shaft 5, and a transmission shaft 32 connected together in sequence by threads. A rubber stator 3 corresponding to the rotor 4 is fixedly installed inside the power housing 34. An upper mandrel sleeve 35 is installed between the shaft housing 7 and the shaft 5. A lower mandrel sleeve 36 is installed between the end sleeve 28 and the transmission shaft 32. A roller bearing assembly and an oil bath bearing assembly are respectively installed between the transmission shaft housing 18 and the transmission shaft 32.

[0024] The rotor 4 has an outer helical groove on its outer wall, and an inner helical groove with the same pitch as the outer helical groove is provided on the inner wall of the rubber stator 3. One lead of the outer and inner helical grooves forms a sealing cavity, also known as a stage. The rotor 4 and the rubber stator 3 mesh with each other, forming a helical sealing line based on the difference in their leads, thus creating a sealing cavity. As the rotor 4 rotates within the rubber stator 3, the sealing cavity moves axially, continuously forming and disappearing, completing its energy conversion. This allows the rubber stator 3 and rotor 4 to constitute a hydraulic drive motor based on the moiré principle. The torque output of the hydraulic drive motor is proportional to the motor pressure drop, and the speed is proportional to the flow rate. The hydraulic drive motor simultaneously increases the number of helical groove heads on the rubber stator 3 and rotor 4 to reduce the speed, and the number of stages to increase the motor torque. The required working pressure and flow rate of this motor are matched with the speed and torque of a grinding shoe or a cutting tool to obtain the optimal speed and torque. The optimal speed and torque can better realize downhole coiled tubing milling and cutting operations.

[0025] A flow cavity 37 is reserved between the upper part of the shaft 5, the power housing 34, and the shaft housing 7. A countersunk hole 38 communicating with the center hole of the drive shaft 32 is provided in the lower part of the shaft 5. A flow hole 33 communicating with the flow cavity 37 is provided on the side wall of the countersunk hole 38. In this way, the mud driven by the hydraulic motor can pass through the flow cavity 37 and the flow hole 33 in sequence and then be discharged from the center hole of the drive shaft 32.

[0026] See Figure 2 The roller bearing assembly includes an adjusting shim 11, a retaining ring 12, and a long shaft sleeve 17 sequentially fitted onto the drive shaft 32. A set of first semi-circular grooves is formed on the upper inner wall of the long shaft sleeve 17, and a set of second semi-circular grooves corresponding to the first semi-circular grooves are formed on the upper external threaded end face of the drive shaft 32. The first semi-circular grooves and the long shaft sleeve form a circular hole. A pin 14, which rolls in contact with the drive shaft 32, is installed in each circular hole, and the end of the pin 14 contacts the retaining ring 12. This invention prevents the drive shaft 32 from rotating by the roller bearing assembly, ensuring smooth operation of the motor for continuous tubing.

[0027] See Figure 3 The oil bath bearing assembly includes an annular boss 40 on the inner wall of the drive shaft housing 18, and a long bushing 17 and a short bushing 24 fitted on the drive shaft 32. An oil injection hole is provided radially on the annular boss 40, and an oil plug 23 is threaded into the oil injection hole. A set of connecting shafts 22 is inserted axially into the annular boss 40. Two stop discs 21 are symmetrically connected to both ends of the set of connecting shafts 22. A short bushing 24 is fitted on the drive shaft 32 between the two stop discs 21. An oil passage hole 39 is provided at the lower end of the long bushing 17. An inner sleeve 10 is fitted on the upper part of the long bushing 17 to form an oil sealing piston. A backstop ring 25 is also fitted on the drive shaft 32 below the lower stop disc 21. A steel ball 26 is embedded between the backstop ring 25 and the drive shaft 32. In addition, the steel ball 26 and the anti-reverse ring 25 constitute a thrust bearing, which is easy to replace, reducing the cost of maintenance tools and consequently reducing the maintenance costs for oilfield customers, thus achieving the effect of cost reduction and efficiency improvement.

[0028] The sealing piston includes an inner sleeve 10 fitted onto a long shaft sleeve 17, with the upper end of the inner sleeve 10 slidably connected to a groove on the inner wall of the drive shaft housing 18 via a positioning key 9. A dustproof sealing ring A13 and a fifth sealing ring 16 are respectively installed between the inner sleeve 10 and the long shaft sleeve 17, and a fourth sealing ring 15 is installed between the inner sleeve 10 and the drive shaft housing 18. A wear-resistant pad 20 is installed between the stop disc 21 and the long shaft sleeve 17 or the anti-reverse ring 25. This invention employs an oil bath bearing assembly to improve the wear resistance and impact resistance of the motor used in continuous tubing, enhance the lead and sealing capability, improve energy conversion efficiency, and extend the working life of the shaft.

[0029] In addition, to improve the sealing performance between the components, a first sealing ring 2 is installed at the connection between the short section 1 and the power housing 34, a second sealing ring 6 is installed at the connection between the power housing 34 and the shaft housing 7, a third sealing ring 8 is installed at the connection between the shaft housing 7 and the drive shaft housing 18, a seventh sealing ring 27 is installed at the connection between the drive shaft housing 18 and the end sleeve 28, and a sixth sealing ring 19 is installed between the lower end of the long shaft sleeve 17 and the drive shaft 32.

[0030] Working principle of the invention:

[0031] The application of the coiled tubing motor in coiled tubing milling technology of the present invention refers to the following: after the coiled tubing machine drives the coiled tubing and the milling tool string at its front end to the target position, working fluid is pumped in through the surface equipment. The working fluid enters the tool string (coiled tubing + connector + double-lobe check valve + hydraulic release + hydraulic anchor + workover screw motor + milling tool) through the coiled tubing to drive the coiled tubing motor, which in turn drives the milling tool to rotate. Through reasonable working pressure difference and drilling pressure control, the milling tool can automatically take in the object to be milled under the action of drilling pressure, and under the action of torque, it can move forward to shear and mill it.

[0032] In practical implementation, high-pressure mud is first introduced into the spiral groove between the rubber stator 3 and the rotor 4. The high-pressure mud drives the rotor 4 to rotate and output torque, which in turn drives the shaft 5 and the transmission shaft 32 to rotate together. Simultaneously, the upper mandrel sleeve 35 on the shaft 5 and the lower mandrel sleeve 36 on the transmission shaft 32 respectively perform eccentric compensation, converting the eccentric rotation into fixed-axis rotation. The torque is then transmitted along the centerline to the transmission shaft 32. Finally, the transmission shaft 32 drives the milling or cutting tool at the end of the tool to perform milling or cutting operations. Therefore, this invention can realize coiled tubing milling and cutting operations in highly deviated and horizontal wells, and can also be applied to reaming, milling, or any other operations requiring bottom hole tool rotation in horizontal and highly deviated wells.

Claims

1. A motor for continuous tubing, comprising an outer housing and an internal transmission component mounted within the outer housing, characterized in that: The outer housing is composed of a short section (1), a power housing (34), a shaft housing (7), a transmission shaft housing (18), and an end sleeve (28) connected in sequence by threads. The internal transmission component is composed of a rotor (4), a shaft (5), and a transmission shaft (32) connected in sequence by threads. A rubber stator (3) corresponding to the rotor (4) is fixedly installed inside the power housing (34). An upper mandrel sleeve (35) is installed between the shaft housing (7) and the shaft (5). A lower mandrel sleeve (36) is installed between the end sleeve (28) and the transmission shaft (32). Roller bearing assemblies and oil bath bearing assemblies are respectively installed between them; the roller bearing assembly includes an adjusting shim (11), a retaining ring (12), and a long shaft sleeve (17) sequentially fitted on the drive shaft (32). A set of first semi-circular grooves is provided on the inner wall of the upper end of the long shaft sleeve (17), and a set of second semi-circular grooves corresponding to the first semi-circular grooves are provided on the external thread end face of the upper end of the drive shaft (32). The first semi-circular grooves and the first semi-circular grooves form a circular hole. A pin (14) that rolls in contact with the drive shaft (32) is installed in each circular hole, and the end of the pin (14) contacts the retaining ring (12); the oil bath bearing assembly includes a set of The inner wall of the drive shaft housing (18) has an annular boss (40) and a long bushing (17) and a short bushing (24) fitted on the drive shaft (32). An oil filling hole is radially provided on the annular boss (40), and an oil plug (23) is threaded into the oil filling hole. A set of connecting shafts (22) is axially inserted into the annular boss (40). Two stop discs (21) are symmetrically connected to both ends of the set of connecting shafts (22). A short bushing (24) is fitted on the drive shaft (32) between the two stop discs (21). An oil passage hole (39) is provided at the lower end of the long bushing (17), and an inner sleeve (24) is fitted on the upper part of the long bushing (17). 10) A sealing piston is formed. A retaining ring (25) is also fitted on the drive shaft (32) and below the lower stop plate (21). A steel ball (26) is embedded between the retaining ring (25) and the drive shaft (32). The sealing piston includes an inner sleeve (10) fitted on a long shaft sleeve (17). The upper end of the inner sleeve (10) is slidably connected to the sliding groove on the inner wall of the drive shaft housing (18) through a positioning key (9). A dustproof sealing ring A (13) and a fifth sealing ring (16) are respectively installed between the inner sleeve (10) and the long shaft sleeve (17). A fourth sealing ring (15) is installed between the inner sleeve (10) and the drive shaft housing (18).

2. The motor for continuous tubing according to claim 1, characterized in that: The outer wall of the rotor (4) is provided with an outer spiral groove, and the inner wall of the rubber stator (3) is provided with an inner spiral groove with the same pitch as the outer spiral groove, and the outer spiral groove and the inner spiral groove are arranged in a staggered manner.

3. The motor for continuous tubing according to claim 1, characterized in that: A flow cavity (37) is reserved between the upper part of the shaft (5), the power housing (34), and the shaft housing (7). A countersunk hole (38) communicating with the center hole of the transmission shaft (32) is provided in the lower part of the shaft (5). A flow hole (33) communicating with the flow cavity (37) is provided on the side wall of the countersunk hole (38).

4. The motor for continuous tubing according to claim 1, characterized in that: A wear-resistant pad (20) is installed between the stop plate (21) and the long shaft sleeve (17) or the anti-reverse ring (25).

5. A method of using a motor for continuous tubing as described in any one of claims 1 to 4, characterized in that: First, high-pressure slurry is introduced into the spiral groove between the rubber stator (3) and the rotor (4). The high-pressure slurry drives the rotor (4) to rotate and outputs torque, which in turn drives the shaft (5) and the transmission shaft (32) to rotate together. At the same time, the upper mandrel sleeve (35) on the shaft (5) and the lower mandrel sleeve (36) on the transmission shaft (32) respectively perform eccentric compensation on the shaft (5) and the transmission shaft (32), converting the eccentric rotation into fixed-axis rotation. Then, the torque is transmitted to the transmission shaft (32) along the center line. Finally, the transmission shaft (32) drives the grinding shoe or cutter at the end of the tool to perform grinding or cutting operations.

6. The method of using the motor for continuous tubing according to claim 5, characterized in that: The rubber stator (3) and rotor (4) constitute a hydraulic drive motor based on the monotro principle, and the hydraulic drive motor is provided with three or more stages.

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