Coiled tubing drilling centralizer and method

Abstract

The present application relates to the technical field of coiled tubing drilling, and discloses a coiled tubing drilling centralizing device and method. The coiled tubing drilling centralizing device comprises a downhole motor and a pull rope. The downhole motor is provided with a tubing connecting structure adapted to the bottom end of the coiled tubing. The output shaft of the downhole motor is drivingly connected with a drill bit. The present application has a reasonable and compact structure, and is convenient to use. During drilling, the two half cylinders can move horizontally away from the coiled tubing and be supported on the well wall, so as to provide horizontal support for the bottom of the coiled tubing, effectively centralize and fix the drilling direction of the drill bit, reduce the influence of the stratum on the drill bit, greatly reduce the horizontal deviation of the drill bit during drilling, make the well trajectory coincide with the predetermined target, and effectively improve the accuracy, stability and operation efficiency of the coiled tubing drilling. In addition, the present application can provide effective support for the bottom of the coiled tubing, reduce the flexural force exerted by the drill bit on the coiled tubing, avoid deformation of the coiled tubing, and reduce the probability of damage to the coiled tubing.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of coiled tubing drilling, and is a coiled tubing drilling centralizer device and method. BACKGROUND

[0002] In the exploration and development of oil, gas and other resources, coiled tubing drilling technology, as an efficient and flexible drilling method, has been widely used. However, in the drilling process of the coiled tubing, the drill bit is prone to lateral deviation due to the influence of the formation, the well trajectory deviates from the predetermined target, thereby affecting the accuracy and efficiency of drilling. For example, in the drilling process, the hardness of the geological layers on both sides of the drill bit is different, resulting in different cutting forces of the drill bit on different geological layers, thereby causing the drilling direction of the drill bit to tilt. In addition, the stiffness, torsional resistance and other properties of the coiled tubing also affect the drilling efficiency and accuracy, because the drill bit is arranged at the bottom end of the coiled tubing, and in the drilling process, the drill bit will exert a bending force on the coiled tubing, which is easy to cause the deformation of the coiled tubing and cause damage to the coiled tubing.

[0003] At present, there are some technical solutions for the problem of lateral deviation of the drill bit. For example, by optimizing the structural design and material selection of the drill bit, the anti-deviation ability is improved; or advanced guiding systems and control strategies are used to accurately control the drilling direction of the drill bit. However, these methods often involve complex equipment modification and operation adjustment, which is high in cost and difficult to implement.

[0004] The Chinese patent document with publication number CN220015084U discloses a coiled tubing special centralizer, which includes a centralizer body provided with an inner through hole matched with the outer diameter of the coiled tubing; the upper, middle and lower parts of the centralizer body are respectively provided with upper, middle and lower clamping grooves, and the upper, middle and lower clamping grooves are respectively clamped with upper, middle and lower contact rings; the contact surfaces of the upper, middle and lower contact rings are protruded from the outer surface of the centralizer body. It greatly reduces the friction between the coiled tubing and the casing by centralizing the coiled tubing, and improves the running-in ability of the coiled tubing. However, it cannot well centralize the drill bit position according to the stress condition of the drill bit during the drilling process of the drill bit, and avoid the lateral deviation of the drill bit.

[0005] The Chinese patent document with the publication number CN219754485U discloses a centralizer for coiled tubing, which includes a shell and balls. The shell is provided with at least two parts and is connected by butt joint of butt joint edges. The inner surface of the shell is arranged with wedge teeth. The balls are arranged longitudinally outside the shell. The outer end surface of the shell is provided with at least two groups of flow guides. The centralizer has high adaptability. The special tooth type inside the shell is used to lock the position of the centralizer, so that the centralizer cannot move up and down. Workers can install the centralizer at any position according to the actual well conditions. When the centralizer is fixed on the tubing, the friction force can be increased to prevent the centralizer from moving up and down. The tubing is not damaged. The balls outside the centralizer can change the original sliding friction into rolling friction. However, the centralizer has poor effect on the centralization of the drill bit which is laterally deviated in the drilling process.

[0006] Therefore, it is of great significance to develop a coiled tubing drilling centralizer with simple structure, convenient operation and low cost for improving the precision and efficiency of coiled tubing drilling operation. SUMMARY

[0007] The present application provides a coiled tubing drilling centralizer and method, which overcomes the shortcomings of the prior art. The present application can effectively solve the problem that the drill bit is easily deviated laterally due to the influence of the formation during the coiled tubing drilling process, the well trajectory deviates from the predetermined target, and the precision and efficiency of drilling are affected.

[0008] One of the technical solutions of the present application is as follows: a coiled tubing drilling centralizer, which comprises a downhole motor and a pull rope. The downhole motor is provided with a tubing connection structure adapted to the bottom end of the coiled tubing. The output shaft of the downhole motor is drivingly connected with a drill bit.

[0009] The upper side of the downhole motor corresponding to the position of the tubing connection structure is provided with two open half-cylinders opposite to each other, and a gap is left between the two half-cylinders. The two half-cylinders are connected together through a plurality of elastic expansion parts. The inner cavities of the two half-cylinders are combined together to form an axial cavity. A driving part is arranged in the axial cavity, which can drive the two half-cylinders to move away from each other. The middle inner side of the driving part is provided with an axial channel for the coiled tubing to pass through.

[0010] The output shaft of the downhole motor has an axial hollow channel. The inner side of the upper part of the drill bit is provided with a transmission cavity which is in communication with the axial hollow channel. A transmission part is arranged in the transmission cavity. The pull rope is connected with the transmission part and the driving part after passing through the axial hollow channel. The transmission part can rotate with the drill bit. The centrifugal force acting on the transmission part can be transmitted to the driving part through the pull rope, so that the two half-cylinders move laterally away from each other and are supported on the well wall.

[0011] The following is a further optimization or / and improvement of the above-mentioned technical solutions:

[0012] The aforementioned drive unit may include an upper drive cylinder, which is located on the inner side of the upper part of the axial cavity. The upper drive cylinder has an axial channel in the middle for the continuous oil pipe to pass through. The upper outer side of the upper end of the upper drive cylinder has an inverted conical outer ring platform with a shape that is larger at the top and smaller at the bottom. The inner side of the upper end of the two semi-cylinders has a conical inner ring groove that is complementary to the shape of the inverted conical outer ring platform. The outer side wall of the inverted conical outer ring platform abuts against the inner side wall of the conical inner ring groove. At least two pull rope connection points are evenly distributed along the circumference at the lower end of the upper drive cylinder. Each pull rope connection point is connected to a pull rope. The other end of all the pull ropes passes through the axial hollow channel and is connected to the transmission unit.

[0013] The aforementioned drive unit may further include a lower drive cylinder and a first synchronization structure. The lower drive cylinder is provided on the inner side of the lower part of the axial cavity, and an axial channel for the continuous tubing to pass through is provided in the middle of the lower drive cylinder. A conical outer ring platform with a shape that is smaller at the top and larger at the bottom is provided on the outer side of the lower end of the lower drive cylinder. An inverted conical inner ring groove that complements the shape of the conical outer ring platform is provided on the inner side of the lower end of the two semi-cylinders. The outer side wall of the conical outer ring platform abuts against the inner side wall of the inverted conical inner ring groove. A first rope-passing hole is provided on the lower drive cylinder at the corresponding position of the pull rope connection point for the pull rope to pass through.

[0014] At least two first synchronization structures can be evenly distributed along the circumference between the upper drive cylinder and the lower drive cylinder to achieve synchronous movement of the upper drive cylinder and the lower drive cylinder towards or away from each other; each first synchronization structure can include an upper longitudinal rack, a lower longitudinal rack and an intermediate gear. The upper end of the upper longitudinal rack is mounted on the lower end face of the upper drive cylinder, and the lower longitudinal rack is mounted on the upper end face of the lower drive cylinder corresponding to the left or right position of the upper longitudinal rack. The tooth surfaces of the lower longitudinal rack and the upper longitudinal rack are opposite to each other; an intermediate gear meshes between the upper longitudinal rack and the lower longitudinal rack.

[0015] The aforementioned transmission unit may include an upper support block, a lower support block, and a counterweight block. A second rope-passing hole is provided on the drill bit corresponding to the axial hollow channel position for the pull rope to pass through. An upper support block and a lower support block are fixedly installed on the upper and lower sidewalls of the transmission cavity corresponding to the second rope-passing hole position, respectively. The upper and lower support blocks divide the transmission cavity into a symmetrical left and right half-cavity. A counterweight block is slidably installed in both the left and right half-cavities, and the counterweight blocks can only move towards or away from each other along the length of the transmission cavity. A third rope-passing hole is provided on the upper support block corresponding to the second rope-passing hole position, and a fourth rope-passing hole is provided in the lower middle part of the upper support block, connecting the left and right half-cavities. The middle part of the fourth rope-passing hole is connected to the lower part of the third rope-passing hole. Each pull rope passes through the axial hollow channel, the second rope-passing hole, the third rope-passing hole, and the fourth rope-passing hole sequentially from top to bottom before connecting to the corresponding counterweight block. The number of pull ropes connected to the two counterweight blocks is equal.

[0016] The second synchronization structure can include a transverse rack and a middle gear, the middle part of the upper support block and the upper part of the lower support block are provided with the transverse rack, and the tooth surfaces of the two transverse racks are opposite, the left end of the upper transverse rack is connected with the right side of the counterweight in the left half cavity, and the right end of the lower transverse rack is connected with the left side of the counterweight in the right half cavity; the middle gear is engaged between the two transverse racks and is rotatably arranged on the inner side of the middle part of the transmission cavity through an axle.

[0017] The front part and the rear part of the two half cylinders are respectively provided with at least one elastic expansion part, each elastic expansion part can include an inner sleeve rod, an outer sleeve tube and a tension spring, the right side of the front part or the right side of the rear part of the left half cylinder is provided with at least one inner sleeve rod, the outer side of the right part of each inner sleeve rod is sleeved with an outer sleeve tube, and the right ends of all the outer sleeve tubes are fixedly arranged on the left side of the right half cylinder; the outer side of each outer sleeve tube is sleeved with a tension spring, the right end of each tension spring is connected with the right half cylinder, and the left end of each tension spring is connected with the left half cylinder.

[0018] The lower side of the two half cylinders and the upper side of the downhole motor are provided with an annular seat, the annular seat is provided with a fifth rope passing eye for the passing of the pull rope, the fifth rope passing eye and the axial hollow hole form a rope passing hole, and the middle part of the pull rope is provided with an anti-winding part sleeved in the rope passing hole to prevent the mutual winding of the pull ropes.

[0019] The fifth rope passing eye can include a longitudinal hole section, a transverse hole section and a guide hole section, the longitudinal hole section is located on the upper part of the annular seat, the transverse hole section is located on the middle part of the annular seat, the guide hole section is located on the lower part of the annular seat, the lower end of the longitudinal hole section and the upper end of the guide hole section are in communication with the transverse hole section, and the anti-winding part is slidingly arranged in the guide hole section; the anti-winding part can include a fixed rod and a rotating rod, the fixed rod is guidingly arranged in the guide hole section, the fixed rod can only slide up and down in the guide hole section and cannot rotate in the guide hole section, all the pull ropes are divided into upper and lower two sections, the lower end of the upper section of each pull rope is connected with the upper end of the fixed rod, the lower end of the fixed rod is provided with a rotating mounting hole with an opening downward, the rotating rod is rotatably arranged in the rotating mounting hole, and the upper end of the lower section of each pull rope is connected with the lower end of the rotating rod.

[0020] The application further includes a plurality of balls, and the outer sides of the two half cylinders are provided with the balls.

[0021] The second technical scheme of the application is realized by the following measures: a continuous oil pipe drilling righting method adopts the continuous oil pipe drilling righting device, and the device comprises:

[0022] The coiled tubing drilling centralizer is connected to the coiled tubing drilling centralizer bottom end, and is lowered into the wellbore; the ground mud pump is started, and high-pressure mud is injected into the coiled tubing, and the high-pressure mud can drive the downhole motor to rotate, and drive the drill bit to rotate to realize drilling operation;

[0023] During drilling, the two counterweights rotate with the drill bit, and the centrifugal force of the two counterweights can be transmitted to the lower end of the upper drive cylinder through the pull rope, the upper drive cylinder moves the lower drive cylinder in the same direction through the first synchronization structure, and the upper drive cylinder moves through the inverted conical outer ring table, and the lower drive cylinder moves through the conical outer ring table, so that the two half cylinders can move away from each other in the direction of resisting the pre-tightening force of the elastic expansion part, until the outer side walls of the two half cylinders support or abut on the well wall, to provide lateral support for the bottom of the coiled tubing and the drill bit, so that the drilling direction of the drill bit is centered and fixed, to reduce the lateral deviation of the drill bit during drilling, and ensure that the well trajectory coincides with the predetermined target.

[0024] The present application has reasonable and compact structure, and is convenient to use, and during drilling, the two half cylinders can move laterally away from the coiled tubing and support on the well wall, to provide lateral support for the bottom of the coiled tubing, thereby effectively centering and fixing the drilling direction of the drill bit, reducing the influence of the formation on the drill bit, greatly reducing the lateral deviation of the drill bit during drilling, making the well trajectory coincide with the predetermined target, effectively improving the precision, stability and operation efficiency of coiled tubing drilling; in addition, the present application can also provide effective support for the bottom of the coiled tubing, reduce the bending force exerted by the drill bit on the coiled tubing, reduce the deformation of the coiled tubing, and greatly reduce the probability of damage to the coiled tubing.

[0025] The centrifugal force of the counterweight can be automatically adjusted according to the rotational speed of the drill bit, so that the pulling force of the pull rope on the upper drive cylinder is positively correlated with the rotational speed of the drill bit, and the lateral support force between the two half cylinders and the well wall can be flexibly adjusted according to the actual working state of the drill bit, thereby improving the efficiency and safety of drilling operation. During the lowering of the coiled tubing, the rotating ball can change the sliding friction between the coiled tubing and the well wall into rolling friction, greatly reducing the friction between the coiled tubing and the well wall, effectively reducing the lowering resistance of the coiled tubing, making the lowering process of the coiled tubing more smooth, thereby improving the operation efficiency of the coiled tubing drilling operation. The first synchronization structure and the second synchronization structure can ensure that the drill bit maintains dynamic balance during rotation, reduces vibration and wear, and prolongs the service life of the drill bit and the coiled tubing.

[0026] In addition, the structure design of the present application is relatively simple, the connection and action mechanism between the components are clear, so that the operation and maintenance become relatively easy. At the same time, since the deviation and vibration of the drill bit are reduced, the wear of the equipment is reduced, and the maintenance cost is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 2 is a schematic view of a cross-sectional structure of the embodiment 1 of the present application. Figure 1 Figure 3 is a schematic view of a cross-sectional structure of the embodiment 2 of the present application.

[0028] Figure 4 is a schematic view of a cross-sectional structure of the embodiment 3 of the present application. Figure 2 Figure 5 is a schematic view of a cross-sectional structure of the embodiment 4 of the present application. Figure 1 Figure 6 is a schematic view of a cross-sectional structure of the embodiment 5 of the present application.

[0029] Figure 7 is a schematic view of a cross-sectional structure of the embodiment 6 of the present application. Figure 3 Figure 8 is a schematic view of a cross-sectional structure of the embodiment 7 of the present application. Figure 1 Figure 9 is a schematic view of a cross-sectional structure of the embodiment 8 of the present application.

[0030] Figure 10 is a schematic view of a cross-sectional structure of the embodiment 9 of the present application. Figure 4 Figure 11 is a schematic view of a cross-sectional structure of the embodiment 10 of the present application.

[0031] In the drawings, the codes are as follows: 1 is a downhole motor, 2 is a pull rope, 3 is a coiled tubing, 4 is a drill bit, 5 is a semi-cylinder, 6 is an axial cavity, 7 is an axial hollow hole, 8 is a transmission cavity, 9 is an upper driving cylinder, 10 is an inverted conical outer ring table, 11 is a lower driving cylinder, 12 is a conical outer ring table, 13 is a first rope eye, 14 is an upper longitudinal rack, 15 is a lower longitudinal rack, 16 is a middle gear, 17 is an upper support block, 18 is a lower support block, 19 is a counterweight block, 20 is a second rope eye, 21 is a left half cavity, 22 is a right half cavity, 23 is a third rope eye, 24 is a fourth rope eye, 25 is a transverse rack, 26 is a middle gear, 27 is an inner sleeve rod, 28 is an outer sleeve tube, 29 is a tension spring, 30 is an annular seat, 31 is a longitudinal hole section, 32 is a transverse hole section, 33 is a guide hole section, 34 is a fixed rod, 35 is a rotating rod, 36 is a ball, and 37 is a ball mounting groove. DETAILED DESCRIPTION

[0032] The present application is not limited by the following embodiments, and the specific implementation manners can be determined according to the technical solutions of the present application and the actual situation.

[0033] In the present application, for the convenience of description, the relative position relationship of each component is described according to the layout mode of the drawings attached to the specification, such as the position relationship of front, back, up, down, left, right, etc. is determined according to the layout direction of the drawings attached to the specification. Figure 1

[0034] The present application will be further described below in combination with the embodiments and the drawings:

[0035] Embodiment 1: as shown in the drawings, the coiled tubing drilling centralizer device includes a downhole motor 1 and a pull rope 2, the downhole motor 1 is provided with a coiled tubing connection structure matched with the bottom end of the coiled tubing 3, and the output shaft of the downhole motor 1 is drivingly connected with a drill bit 4. Figures 1 to 4

[0036] ​​In the technical solution, the downhole motor 1 and the tubing connection structure thereon are known in the art, and the downhole motor 1 applied to the coiled tubing 3 generally adopts a screw motor or a turbine motor. The downhole motor 1 is connected to the bottom end of the coiled tubing 3 through a coiled tubing 3 adapter, and the structure can adopt a known structure in the art, wherein the bottom end or the bottom of the coiled tubing 3 is the end close to the bottom of the well. The transmission structure between the output shaft of the hydraulic motor and the drill bit 4 can also adopt the existing technology in the art.

[0037] During use, high-pressure mud is pumped into the coiled tubing 3 by a surface mud pump, the high-pressure mud is delivered to the downhole motor 1 through the coiled tubing 3, and the downhole motor 1 can convert the pressure energy of the high-pressure mud into the rotary motion of the output shaft thereof through mechanical action to drive the drill bit 4 to rotate, thereby realizing drilling operation. In addition, the mud injected into the well can also lubricate and cool the drill bit 4, and maintain the pressure balance in the well. The mud returned to the ground through the wellbore annulus can carry the cuttings back to the ground and clean the wellbore.

[0038] Corresponding to the position of the tubing connection structure, the upper side of the downhole motor 1 is provided with two open half-cylinders 5 opposite to each other, and a gap is left between the two half-cylinders 5. The two half-cylinders 5 are connected together through a plurality of elastic expansion parts, and the inner cavities of the two half-cylinders 5 are combined together to form an axial cavity 6. The axial cavity 6 is provided with a driving part capable of driving the two half-cylinders 5 to move away from each other, and the inner side of the middle part of the driving part is provided with an axial channel for the coiled tubing 3 to pass through.

[0039] In the technical solution, the shape of the half-cylinder 5 can be tile-shaped or arc-shaped close to a semicircle. After the two half-cylinders 5 are combined together with the openings opposite to each other, the axes of the two half-cylinders 5 coincide, that is, the left half-cylinder 5 is coaxially connected with the right half-cylinder 5. Under normal circumstances, the two half-cylinders 5 connected together through the elastic expansion parts can form a complete cylinder. In order to make the stress of the two half-cylinders 5 more balanced, the two half-cylinders 5 can be arranged in left-right symmetry to better realize the centralizing effect.

[0040] According to the requirements, the elastic expansion part can adopt a connecting piece with elastic expansion capability in the existing technology, such as an elastic rubber piece, a tension spring, etc. In order to smoothly lower the invention into the well through the coiled tubing 3, the outer diameter of the mud pump is equal to the outer diameter of the drill bit 4, but the outer diameters of the two are slightly larger than the outer diameter of the coiled tubing 3.

[0041] The output shaft of the downhole motor 1 has an axial hollow hole 7, the upper part of the drill bit 4 is provided with a transmission cavity 8 which is in communication with the axial hollow hole 7, the transmission cavity 8 is provided with a transmission part, and the two ends of the pull rope 2 are connected with the transmission part and the driving part respectively after passing through the axial hollow hole 7; the transmission part can rotate with the drill bit 4, and the centrifugal force received by the transmission part can be transmitted to the driving part through the pull rope 2, so that the two half cylinders 5 move in the direction away from each other, and are supported on the well wall.

[0042] In the above technical solution, the driving part is sleeved outside the bottom of the coiled tubing 3, and the two half cylinders 5 are sleeved outside the driving part; in order to facilitate the connection of the pull rope 2 with the driving part and the transmission part, the bottom of the coiled tubing 3 is provided with a rope eye which is matched with the pull rope 2.

[0043] In use, the downhole motor 1 is first connected to the bottom end of the coiled tubing 3 through the coiled tubing 3 adapter, then the driving part is sleeved outside the bottom of the coiled tubing 3, and then the two half cylinders 5 are installed outside the driving part by buckling, and the two half cylinders 5 are connected together through the elastic expansion part; at this time, under the pre-tightening force of the elastic expansion part, the two half cylinders 5 are contracted and folded outside the driving part; finally, one end of the pull rope 2 is connected with the driving part, and the other end is connected with the transmission part after passing through the rope eye on the coiled tubing 3 and the axial hollow hole 7 of the output shaft of the downhole motor 1 in sequence; the transmission part is installed in the transmission cavity 8 on the upper part of the drill bit 4, and the drill bit 4 is drivingly connected with the output shaft of the downhole motor 1.

[0044] After the installation of the downhole motor 1 and the coiled tubing 3 and the installation of other ground equipment are completed, the coiled tubing 3 and the downhole motor 1 are sent into the wellbore. The ground mud pump is started, and high-pressure mud is injected into the coiled tubing 3, which can drive the downhole motor 1 to operate, and the output shaft of the downhole motor 1 drives the drill bit 4 to rotate, thereby realizing drilling operation.

[0045] During the drilling operation, the transmission part can rotate with the drill bit 4, and the centrifugal force received by the transmission part due to the rotation of the drill bit 4 can be transmitted to the driving part through the pull rope 2, so that the driving part can drive the two half cylinders 5 to move away from each other against the pre-tightening force of the elastic expansion part, that is, to move away from the coiled tubing 3 or to move laterally, so that the two half cylinders 5 are expanded laterally until the outer side walls of the two half cylinders 5 are supported or abutted on the well wall, so as to provide lateral support for the bottom of the coiled tubing 3, thereby realizing the centralizing and fixing of the drill bit 4, so that the drilling direction of the drill bit 4 is centered and fixed, and the lateral deviation of the drill bit 4 during drilling is greatly reduced; in addition, the downhole motor 1 can also provide effective support for the bottom of the coiled tubing 3, reduce the bending force applied by the drill bit 4 to the coiled tubing 3, and reduce the torsional deformation of the coiled tubing 3, thereby greatly reducing the probability of damage to the coiled tubing 3.

[0046] When the downhole motor 1 stops operating, the drill bit 4 also stops rotating, the drive unit no longer generates centrifugal force, and the two semi-cylinders 5 move and reset towards each other under the elastic restoring force of the elastic expansion joint.

[0047] The present invention has a reasonable and compact structure and is easy to use. During the drilling process, the two semi-cylinders 5 can move laterally away from the coiled tubing 3 and be supported on the well wall to provide lateral support for the bottom of the coiled tubing 3. This effectively straightens and fixes the drilling direction of the drill bit 4, reduces the influence of the formation on the drill bit 4, greatly reduces the lateral deviation of the drill bit 4 during the drilling process, and makes the wellbore trajectory coincide with the predetermined target, effectively improving the accuracy, stability and operation efficiency of coiled tubing 3 drilling.

[0048] The above-mentioned coiled tubing drilling centralization device can be further optimized and / or improved according to actual needs:

[0049] Example 2: As an optimization of the above examples, as shown in the appendix Figure 1 As shown, the drive unit includes an upper drive cylinder 9. The upper drive cylinder 9 is located on the inner side of the upper part of the axial cavity 6. The upper drive cylinder 9 has an axial channel in the middle for the continuous oil pipe 3 to pass through. The upper outer side of the upper end of the upper drive cylinder 9 is provided with an inverted conical outer ring platform 10 that is larger at the top and smaller at the bottom. The inner side of the upper end of the two semi-cylinders 5 is provided with a conical inner ring groove that is complementary to the shape of the inverted conical outer ring platform 10. The outer side wall of the inverted conical outer ring platform 10 abuts against the inner side wall of the conical inner ring groove. At least two pull rope 2 connection points are evenly distributed along the circumference at the lower end of the upper drive cylinder 9. Each pull rope 2 connection point is connected to a pull rope 2. The other end of all pull ropes 2 passes through the axial hollow channel 7 and is connected to the transmission unit.

[0050] In the above technical solution, the upper drive cylinder 9 is fitted on the outside of the coiled tubing 3 and can move downward (i.e., towards the drill bit 4) or upward (i.e. away from the drill bit 4) along the axial direction of the coiled tubing 3; the inverted conical outer ring platform 10 and the upper drive cylinder 9 can be integrally formed, such as by machining or mold casting; the pull rope 2 and the upper drive cylinder 9 can be connected by eye bolts or eye bolts.

[0051] During drilling, the transmission unit rotates with the drill bit 4. The centrifugal force generated by the rotation of the drill bit 4 is transmitted to the upper drive cylinder 9 through the pull rope 2, causing the upper drive cylinder 9 to be subjected to a downward traction force so that the upper drive cylinder 9 can slide downward along the outer wall of the continuous tubing 3. At this time, the inverted conical outer ring platform 10 moves downward along with the upper drive cylinder 9. The inverted conical outer ring platform 10 moves downward in the conical inner ring groove at the upper end of the semi-cylinder 5, thereby pushing the two semi-cylinders 5 to move away from each other against the preload of the elastic expansion joint, that is, away from the continuous tubing 3. The tubing 3 moves directionally or laterally, causing the two semi-cylinders 5 to expand laterally until the outer walls of the two semi-cylinders 5 support or abut against the well wall, so as to provide lateral support for the bottom of the coiled tubing 3, thereby straightening and fixing the drilling direction of the drill bit 4, greatly reducing the lateral deviation of the drill bit 4 during the drilling process; in addition, the present invention can also provide effective support for the bottom of the coiled tubing 3, reduce the bending force exerted by the drill bit 4 on the coiled tubing 3, reduce the deformation of the coiled tubing 3, and greatly reduce the probability of damage to the coiled tubing 3.

[0052] When the drill bit 4 stops rotating, the upper drive cylinder 9 is no longer subjected to the traction force transmitted by the pull rope 2. Under the action of the elastic restoring force of the elastic expansion joint, the two semi-cylinders 5 move towards each other. During this process, the conical inner ring groove applies an upward pushing force to the inverted conical outer ring platform 10, thereby causing the upper drive cylinder 9 to move upward and reset.

[0053] Example 3: As an optimization of Example 2, as shown in the appendix Figure 1 As shown, the drive unit also includes a lower drive cylinder 11 and a first synchronization structure. The lower drive cylinder 11 is located on the inner side of the lower part of the axial cavity 6, and an axial channel for the continuous oil pipe 3 to pass through is provided in the middle of the lower drive cylinder 11. A conical outer ring platform 12 with a shape that is smaller at the top and larger at the bottom is provided on the outer side of the lower end of the lower drive cylinder 11. An inverted conical inner ring groove with a shape complementary to the conical outer ring platform 12 is provided on the inner side of the lower end of the two semi-cylinders 5. The outer side wall of the conical outer ring platform 12 abuts against the inner side wall of the inverted conical inner ring groove. A first rope-passing hole 13 is provided on the lower drive cylinder 11 at the corresponding connection point of the pull rope 2 for the pull rope 2 to pass through. At least two first synchronization structures are evenly distributed along the circumference between the upper drive cylinder 9 and the lower drive cylinder 11 to realize the synchronous movement of the upper drive cylinder 9 and the lower drive cylinder 11 towards or away from each other.

[0054] With this configuration, the lower drive cylinder 11 is fitted onto the outside of the coiled tubing 3 and can slide up and down along the axis of the coiled tubing 3. The conical outer ring platform 12 and the lower drive cylinder 11 can be integrally formed, such as through machining or mold casting. The first synchronization structure enables the upper drive cylinder 9 and the lower drive cylinder 11 to move synchronously, thereby making the forces on the upper and lower ends of the two semi-cylinders 5 more balanced, resulting in better contact between the two semi-cylinders 5 and the well wall, and achieving better lateral support.

[0055] Each first synchronization structure includes an upper longitudinal rack 14, a lower longitudinal rack 15, and an intermediate gear 16. The upper end of the upper longitudinal rack 14 is mounted on the lower end face of the upper drive cylinder 9. The lower longitudinal rack 15 is mounted on the upper end face of the lower drive cylinder 11, which is located to the left or right of the upper longitudinal rack 14. The tooth surfaces of the lower longitudinal rack 15 are opposite to those of the upper longitudinal rack 14. An intermediate gear 16 meshes between the upper longitudinal rack 14 and the lower longitudinal rack 15.

[0056] In the above technical solution, the intermediate gear 16 can be installed on the corresponding position on the outer side of the bottom of the continuous tubing 3 via a gear shaft. The gear shaft and the intermediate gear 16 can be set separately or as a whole, such as the gear shaft.

[0057] During use, when the upper drive cylinder 9 moves downward under the action of the pull rope 2, the upper longitudinal rack 14 moves downward along with the upper drive cylinder 9, thereby causing the intermediate gear 16 meshing with the upper longitudinal rack 14 to rotate counterclockwise. The counterclockwise rotating intermediate gear 16 can drive the lower longitudinal rack 15 to move upward. The lower longitudinal rack 15 pulls the lower drive cylinder 11 to move upward together, thereby causing the upper drive cylinder 9 and the lower drive cylinder 11 to move synchronously towards each other by an equal distance, moving the two semi-cylinders 5 away from each other by the same distance, forming a lateral support at the bottom of the continuous tubing 3, and at the same time playing a role in straightening and fixing the drilling direction of the drill bit 4, preventing the drill bit 4 from shifting laterally.

[0058] Example 4: As an optimization of the above embodiments, as shown in the appendix. Figures 1 to 2 As shown, the transmission unit includes an upper support block 17, a lower support block 18, and a counterweight block 19. A second rope-passing hole 20 is provided on the drill bit 4 corresponding to the position of the axial hollow channel 7 for the pull rope 2 to pass through. The upper support block 17 and the lower support block 18 are respectively fixedly installed on the upper and lower side walls of the transmission cavity 8 corresponding to the position of the second rope-passing hole 20. The upper support block 17 and the lower support block 18 divide the transmission cavity 8 into a left half-cavity 21 and a right half-cavity 22, which are symmetrically arranged. A counterweight block 19 is slidably installed in both the left half-cavity 21 and the right half-cavity 22. The counterweight block 19 can only move along the transmission cavity 8. The length directions can move towards or away from each other; the upper support block 17 corresponding to the position of the second rope hole 20 is provided with a third rope hole 23 that runs vertically through it, and the lower part of the upper support block 17 is provided with a fourth rope hole 24 that can connect the left half cavity 21 and the right half cavity 22. The middle part of the fourth rope hole 24 is connected to the lower part of the third rope hole 23; each pull rope 2 passes through the axial hollow channel 7, the second rope hole 20, the third rope hole 23 and the fourth rope hole 24 from top to bottom and is connected to the corresponding counterweight block 19. The number of pull ropes 2 connected to the two counterweight blocks 19 is equal.

[0059] In the above technical solution, the transmission cavity 8 and the axial hollow hole 7 are communicated through the second rope passing hole 20, the two counterweights 19 can slide linearly towards or away from each other in the corresponding half cavities, and can only slide along the length direction of the transmission cavity 8 (i.e. the left-right direction in the figure) Figure 1 The upper support block 17 and the lower support block 18 can limit the movement stroke of the two counterweights 19. The two counterweights 19 are equal in weight, the left half cavity 21 and the right half cavity 22 are left-right symmetrical structures, and the two counterweights 19 are installed in the corresponding half cavities in a left-right symmetrical manner to reduce the eccentric force. The number of the pull ropes 2 connected to the two counterweights 19 is equal, so that the stress of each pull rope 2 is equal, the pulling force of the connection points of each pull rope 2 at the lower end of the upper driving cylinder 9 is equal, the pushing force of the upper driving cylinder 9 acting on the two half cylinders 5 is equal, the support force between the two half cylinders 5 and the well wall is equal, and the righting and fixing effect of the drill bit 4 is better.

[0060] In the initial state, the two counterweights 19 are closest to each other, and the upper driving cylinder 9 and the lower driving cylinder 11 are farthest from each other. Under the pre-tightening force of the elastic expansion part, the two half cylinders 5 are in a folded state.

[0061] During drilling, the output shaft of the downhole motor 1 drives the drill bit 4 to rotate, and the two counterweights 19 rotate with the drill bit 4. The higher the rotation speed of the drill bit 4, the greater the centrifugal force acting on the two counterweights 19, and the greater the downward pulling force of the pull rope 2 transmitted to the upper driving cylinder 9, so that the distance between the two half cylinders 5 away from each other is farther, and the transverse support force between the two half cylinders 5 and the well wall is greater, and the directional force of the drill bit 4 is stronger. When the rotation speed of the drill bit 4 decreases, the centrifugal force acting on the two counterweights 19 decreases, the downward pulling force of the pull rope 2 acting on the upper driving cylinder 9 decreases, and the outward pushing force of the upper driving cylinder 9 and the lower driving cylinder 11 to the two half cylinders 5 (towards the well wall) decreases, so that the two half cylinders 5 move towards each other under the elastic restoring force of the elastic expansion part, and the upper driving cylinder 9 and the lower driving cylinder 11 move away from each other to reset, and at the same time, the pull rope 2 is pulled by the upper driving cylinder 9 to reset the two counterweights 19.

[0062] According to the requirement, to avoid the mutual entanglement of the pull ropes 2, the middle part of the pull rope 2 can be provided with an anti-entanglement part, which can be installed in the axial hollow hole 7. All the pull ropes 2 can be divided into upper and lower two sections. The upper end of each upper section pull rope 2 is connected with the pull rope 2 connection point at the lower end of the upper driving cylinder 9. The lower end of all the upper section pull ropes 2 is connected with the upper part of the anti-entanglement part. The lower part of the anti-entanglement part is connected with the upper end of all the lower section pull ropes 2. The lower end of the lower section pull rope 2 is connected with the corresponding counterweight 19. The number of the pull ropes 2 connected to the two counterweights 19 is equal. The anti-entanglement part can adopt a fish mouth, a universal ring, a BD rotating ring, a universal rotating ring, an 8-shaped rotating ring or a rotating ring in the prior art.

[0063] By such arrangement, the centrifugal force acting on the counterweight 19 can be automatically adjusted according to the rotating speed of the drill bit 4, so that the pulling force of the pull rope 2 on the upper driving cylinder 9 is positively correlated with the rotating speed of the drill bit 4, and further, the lateral supporting force between the two half cylinders 5 and the well wall can be flexibly adjusted according to the actual working state of the drill bit 4, thereby improving the efficiency and safety of the drilling operation.

[0064] Embodiment 5: As an optimization of Embodiment 4, as shown in the accompanying Figures 1 to 2 The second synchronization structure is provided between the two counterweights 19 and is capable of synchronously moving the two counterweights 19 towards or away from each other, and the second synchronization structure comprises a lateral rack 25 and a middle gear 26. The middle part of the upper supporting block 17 and the middle part of the lower supporting block 18 are both provided with the lateral rack 25, and the tooth surfaces of the two lateral racks 25 are opposite to each other. The left end of the upper lateral rack 25 is connected to the right side of the counterweight 19 in the left half cavity 21, and the right end of the lower lateral rack 25 is connected to the left side of the counterweight 19 in the right half cavity 22. The middle gear 26 is engaged between the two lateral racks 25 and is rotatably installed in the middle inner side of the transmission cavity 8 through an axle.

[0065] During use, when the two counterweights 19 move away from each other under the action of the centrifugal force, the middle gear 26 rotates counterclockwise, and the two lateral gears are both engaged with the middle gear 26. The engagement points between the two lateral racks 25 and the middle gear 26 are symmetrically arranged above and below each other, so that the two counterweights 19 can synchronously move away from each other by an equal distance, ensuring that the drill bit 4 maintains dynamic balance during rotation, reducing vibration and wear, and prolonging the service life of the drill bit 4 and the coiled tubing 3.

[0066] According to requirements, to avoid affecting the moving stroke of the lateral rack 25, the counterweight 19 at the position corresponding to the free end of each lateral rack 25 is provided with an avoiding notch, and the shape of the avoiding notch is adapted to the shape of the lateral rack 25. The axis of the middle gear 26 is perpendicular to the axis of the drill bit 4, so as to minimize the influence of the present application on the dynamic balance of the drill bit 4 during rotation.

[0067] Embodiment 6: As an optimization of the above-mentioned embodiments, as shown in the accompanying Figure 1 The front part and the rear part of the two half cylinders 5 are respectively provided with at least one elastic expansion part. Each elastic expansion part comprises an inner sleeve rod 27, an outer sleeve tube 28 and a tension spring 29. The front right side or the rear right side of the left half cylinder 5 is provided with at least one inner sleeve rod 27. The outer side of the right part of each inner sleeve rod 27 is sleeved with an outer sleeve tube 28, and the right end of all the outer sleeve tubes 28 is fixedly installed at the corresponding position on the left side of the right half cylinder 5. The outer side of each outer sleeve tube 28 is sleeved with a tension spring 29, and the right end of each tension spring 29 is connected with the right half cylinder 5, and the left end is connected with the left half cylinder 5.

[0068] Through the arrangement, the inner sleeve rod 27 and the outer sleeve tube 28 can guide and support the tension spring 29 without affecting the expansion and contraction of the tension spring 29. The tension spring 29 can provide restoring force for the reset of the two half cylinders.

[0069] Embodiment 7: As an optimization of the above embodiments, as shown in Figure 1 , 3 Fig. 7, an annular seat 30 is arranged between the lower side of the two half cylinders 5 and the upper side of the downhole motor 1, and a fifth rope passing hole is arranged on the annular seat 30 for the tension rope 2 to pass through, the fifth rope passing hole and the axial hollow hole 7 form a rope passing channel, and a winding prevention part is arranged in the middle of the tension rope 2 to prevent the winding of the tension ropes 2.

[0070] In the above technical solution, the annular seat 30 can isolate the two half cylinders 5 from the downhole motor 1, and better support the lower ends of the two half cylinders 5 to avoid misalignment. The winding prevention part can avoid the winding of the tension rope 2 in the axial hollow hole 7 and affect the reset of the two counterweights 19. In order to facilitate the successful lowering of the invention into the well through the coiled tubing 3, the outer diameter of the mud pump, the outer diameter of the drill bit 4 and the outer diameter of the annular seat 30 are equal, but the outer diameters of the three are slightly larger than the outer diameter of the coiled tubing 3.

[0071] Embodiment 8: As an optimization of embodiment 7, as shown in Figure 1 , 3 Fig. 8, the fifth rope passing hole includes a longitudinal hole section 31, a transverse hole section 32 and a guide hole section 33, the longitudinal hole section 31 is located at the upper part of the annular seat 30, the transverse hole section 32 is located at the middle part of the annular seat 30, and the guide hole section 33 is located at the lower part of the annular seat 30, the lower end of the longitudinal hole section 31 and the upper end of the guide hole section 33 are in communication with the transverse hole section 32, and the winding prevention part is slidingly installed in the guide hole section 33; the winding prevention part includes a fixed rod 34 and a rotating rod 35, the fixed rod 34 is guidingly installed in the guide hole section 33, the fixed rod 34 can only slide up and down in the guide hole section 33 and cannot rotate in the guide hole section 33, all the tension ropes 2 are divided into upper and lower sections, the lower end of the upper section of each tension rope 2 is connected with the upper end of the fixed rod 34, the lower end of the fixed rod 34 is provided with a rotating installation hole with an opening downward, the rotating rod 35 is rotatingly installed in the rotating installation hole, and the upper end of the lower section of each tension rope 2 is connected with the lower end of the rotating rod 35.

[0072] Through the arrangement, the winding of the upper sections of the tension ropes 2 can be effectively avoided, and the lower sections of the tension ropes 2 can rotate with the counterweights 19 without winding. According to the requirements, the shape of the fixed rod 34 is complementary to the shape of the guide hole section 33 to realize guiding installation, and the cross-sectional shape of the guide hole section 33 can be drum-shaped, square-shaped, hexagonal-shaped, etc.

[0073] Embodiment 9: As an optimization of the above embodiments, as shown in Figure 1 , 4As shown, it also includes ball bearings 36, and several ball bearings 36 are provided on the outer side of the two semi-cylinders 5.

[0074] During use, when the drilling speed of drill bit 4 decreases to a stop, during the lowering of coiled tubing 3, the rotating ball bearings 36 can transform the sliding friction between coiled tubing 3 and the well wall into rolling friction, greatly reducing the friction between coiled tubing 3 and the well wall, effectively reducing the lowering resistance of coiled tubing 3, making the lowering process of coiled tubing 3 smoother, thereby improving the operating efficiency of coiled tubing 3 drilling operations.

[0075] Depending on the requirements, the ball bearing 36 can be installed on the outside of the two semi-cylinders 5 in the following manner:

[0076] (1) The ball bearing 36 can be a standard hardware component such as a ball bearing or a ball spring plunger in the prior art. When in use, several radial mounting holes with outward openings (i.e., the opening direction is away from the direction of the continuous tubing) are opened at intervals on the outside of the two semi-cylinders 5. Each ball bearing or ball spring plunger is installed in the corresponding radial mounting hole.

[0077] (2) For example Figure 4 As shown, several ball bearing mounting grooves 37 with outward openings are evenly distributed along the circumference of the outer sides of the two semi-cylinders 5, and the length direction of each ball bearing mounting groove 37 is parallel to the axis direction of the semi-cylinder 5; corresponding to the position of each ball bearing mounting groove 37, the upper end face of the two semi-cylinders 5 is provided with a ball bearing inlet that can communicate with the upper end of the ball bearing mounting groove 37. The ball bearing 36 is loaded into each ball bearing mounting groove 37 through the ball bearing inlet, and the outer end of the ball bearing 36 protrudes outside the ball bearing mounting groove 37 and can roll in the ball bearing mounting groove 37; a sealing component is fixedly installed in the ball bearing inlet to prevent the ball bearing 36 from falling out; the sealing component can be a plug, rivet, etc.

[0078] (3) such as Figure 1 As shown, the outer sides of the two semi-cylinders 5 are provided with several outward-facing ball bearing mounting grooves 37, and the length direction of each ball bearing mounting groove 37 is perpendicular to the axial direction of the semi-cylinder 5. The left or right side of the two semi-cylinders 5 corresponding to the position of each ball bearing mounting groove 37 is provided with a ball bearing inlet that can communicate with one end of the ball bearing mounting groove 37. The ball bearing 36 is loaded into each ball bearing mounting groove 37 through the ball bearing inlet, and the outer end of the ball bearing 36 protrudes outside the ball bearing mounting groove 37 and can roll inside the ball bearing mounting groove 37. A sealing element is fixedly installed in the ball bearing inlet to prevent the ball bearing 36 from falling out.

[0079] Example 10: A coiled tubing drilling centering method, employing the aforementioned coiled tubing drilling centering device, comprising:

[0080] The coiled tubing drilling centralizer is connected to the coiled tubing drilling centralizer bottom end of the coiled tubing, and the coiled tubing drilling centralizer is lowered into the wellbore; the ground mud pump is started, and high-pressure mud is injected into the coiled tubing 3, and the high-pressure mud can drive the downhole motor 1 to operate, and drive the drill bit 4 to rotate to realize drilling operation.

[0081] During drilling, the two counterweights 19 rotate with the drill bit 4, and the centrifugal force of the two counterweights 19 can be transmitted to the lower end of the upper drive cylinder 9 through the pull rope 2. The upper drive cylinder 9 moves the lower drive cylinder 11 in the same direction through the first synchronization structure. The upper drive cylinder 9 moves the two half-cylinders 5 away from each other through the inverted conical outer ring table 10 and the lower drive cylinder 11 through the conical outer ring table 12, until the outer side walls of the two half-cylinders 5 support or abut against the well wall, providing lateral support for the bottom of the coiled tubing 3 and the drill bit 4, and the drilling direction of the drill bit 4 is righted and fixed, so as to reduce the lateral deviation of the drill bit 4 during drilling, and ensure that the wellbore trajectory coincides with the predetermined target.

[0082] The structure design of the present application is relatively simple, the connection between the components and the action mechanism are clear, so that the operation and maintenance become relatively easy. At the same time, due to the reduction of the deviation and vibration of the drill bit 4, the wear of the equipment is reduced, and the maintenance cost is reduced.

[0083] The above technical features respectively constitute the embodiments of the present application, which have strong adaptability and implementation effect. Non-essential technical features can be added or reduced according to actual needs to meet the needs of different situations.

Claims

1. A coiled tubing drilling centering device, characterized in that... It includes a downhole motor and a pull rope. The downhole motor is equipped with a tubing connection structure that is compatible with the bottom end of the coiled tubing. The output shaft of the downhole motor is connected to the drill bit. The downhole motor at the location corresponding to the tubing connection structure has two open semi-cylinders with opposite openings on its upper side, and a gap is left between the two semi-cylinders; the two semi-cylinders are connected together by several elastic telescopic parts, and the inner cavities of the two semi-cylinders can be enclosed to form an axial cavity; a drive unit is provided in the axial cavity to drive the two semi-cylinders to move away from each other, and an axial channel for the continuous tubing to pass through is provided on the inner side of the middle part of the drive unit. The output shaft of the downhole motor has an axial hollow channel. The upper inner side of the drill bit is provided with a transmission cavity that communicates with the axial hollow channel. The transmission cavity is equipped with a transmission unit. The two ends of the pull rope pass through the axial hollow channel and are connected to the transmission unit and the drive unit respectively. The transmission unit can rotate with the drill bit, and the centrifugal force it receives can be transmitted to the drive unit through the pull rope, thereby causing the two semi-cylinders to move laterally away from each other and be supported on the well wall.

2. The coiled tubing drilling centering device according to claim 1, characterized in that, The drive unit includes an upper drive cylinder. The upper drive cylinder is located on the inner side of the upper part of the axial cavity. An axial channel for the continuous oil pipe to pass through is provided in the middle of the upper drive cylinder. An inverted conical outer ring platform with a shape that is larger at the top and smaller at the bottom is provided on the outer side of the upper end of the upper drive cylinder. A conical inner ring groove with a shape complementary to the inverted conical outer ring platform is provided on the inner side of the upper end of the two semi-cylinders. The outer side wall of the inverted conical outer ring platform abuts against the inner side wall of the conical inner ring groove. At least two pull rope connection points are evenly distributed along the circumference at the lower end of the upper drive cylinder. A pull rope is connected to each pull rope connection point. The other end of all pull ropes passes through the axial hollow channel and is connected to the transmission unit.

3. The coiled tubing drilling centering device according to claim 2, characterized in that, The drive unit also includes a lower drive cylinder and a first synchronization structure. The lower drive cylinder is provided on the inner side of the lower part of the axial cavity, and the middle part of the lower drive cylinder is provided with an axial channel for the continuous oil pipe to pass through. The lower outer side of the lower end of the lower drive cylinder is provided with a conical outer ring platform with a shape that is smaller at the top and larger at the bottom. The inner side of the lower end of the two semi-cylinders is provided with an inverted conical inner ring groove that complements the shape of the conical outer ring platform. The outer side wall of the conical outer ring platform abuts against the inner side wall of the inverted conical inner ring groove. The lower drive cylinder at the corresponding position of the pull rope connection point is provided with a first rope threading hole for the pull rope to pass through. At least two first synchronization structures are evenly distributed along the circumference between the upper and lower drive cylinders to achieve synchronous movement of the upper and lower drive cylinders towards or away from each other; each first synchronization structure includes an upper longitudinal rack, a lower longitudinal rack, and an intermediate gear. The upper end of the upper longitudinal rack is mounted on the lower end face of the upper drive cylinder, and the lower longitudinal rack is mounted on the upper end face of the lower drive cylinder corresponding to the left or right position of the upper longitudinal rack. The tooth surfaces of the lower longitudinal rack and the upper longitudinal rack are opposite to each other; an intermediate gear meshes between the upper longitudinal rack and the lower longitudinal rack.

4. The coiled tubing drilling centering device according to claim 1, 2, or 3, characterized in that, The transmission unit includes an upper support block, a lower support block, and a counterweight block. A second rope-passing hole is provided on the drill bit corresponding to the axial hollow channel position for the pull rope to pass through. An upper support block and a lower support block are fixedly installed on the upper and lower sidewalls of the transmission cavity corresponding to the second rope-passing hole position, respectively. The upper and lower support blocks divide the transmission cavity into a symmetrical left and right half-cavity. A counterweight block is slidably installed in both the left and right half-cavities, and the counterweight blocks can only move towards or away from each other along the length of the transmission cavity. A third rope-passing hole is provided on the upper support block corresponding to the second rope-passing hole position, and a fourth rope-passing hole is provided in the lower middle part of the upper support block, connecting the left and right half-cavities. The middle part of the fourth rope-passing hole is connected to the lower part of the third rope-passing hole. Each pull rope passes through the axial hollow channel, the second rope-passing hole, the third rope-passing hole, and the fourth rope-passing hole sequentially from top to bottom before connecting to the corresponding counterweight block. The number of pull ropes connected to the two counterweight blocks is equal. Or / and, a second synchronization structure is provided between the two counterweights, enabling them to move synchronously towards or away from each other. The second synchronization structure includes a transverse rack and a central gear. A transverse rack is provided on the lower middle part of the upper support block and the upper middle part of the lower support block, and the tooth surfaces of the two transverse racks are opposite each other. The left end of the upper transverse rack is connected to the corresponding position on the right side of the counterweight in the left half cavity, and the right end of the lower transverse rack is connected to the corresponding position on the left side of the counterweight in the right half cavity. A central gear meshes between the two transverse racks, and the central gear is mounted on the inner side of the middle of the transmission cavity through a wheel axle rotation.

5. The coiled tubing drilling centering device according to claim 1, 2, or 3, characterized in that, At least one elastic telescopic part is provided between the front and rear parts of the two semi-cylinders. Each elastic telescopic part includes an inner sleeve rod, an outer sleeve tube, and a tension spring. At least one inner sleeve rod is provided on the right side of the front or rear of the left semi-cylinder. An outer sleeve tube is fitted on the outer side of the right side of each inner sleeve rod. The right ends of all outer sleeve tubes are fixedly installed at the corresponding positions on the left side of the right semi-cylinder. A tension spring is fitted on the outer side of all outer sleeve tubes. The right end of each tension spring is connected to the right semi-cylinder, and its left end is connected to the left semi-cylinder.

6. The coiled tubing drilling centering device according to claim 4, characterized in that, The elastic telescopic part includes an inner sleeve rod, an outer sleeve tube, and a tension spring. At least one inner sleeve rod is provided on the front right side and the rear right side of the left semi-cylinder. An outer sleeve tube is fitted on the outer side of the right side of each inner sleeve rod. The right ends of all the outer sleeve tubes are fixedly installed at the corresponding positions on the left side of the right semi-cylinder. A tension spring is fitted on the outer side of all the outer sleeve tubes. The right end of each tension spring is connected to the right semi-cylinder, and its left end is connected to the left semi-cylinder.

7. The coiled tubing drilling centering device according to claim 1, 2, 3, or 6, characterized in that, An annular seat is provided between the lower side of the two semi-cylinders and the upper side of the downhole motor. The annular seat has a fifth rope hole for the pull rope to pass through. The fifth rope hole and the axial hollow channel form a rope passage. The middle of the pull rope is provided with an anti-winding part fitted into the rope passage to prevent the pull ropes from getting tangled together. Or / and, the fifth rope threading hole includes a longitudinal section, a transverse section, and a guide section. The longitudinal section is located on the upper part of the annular seat, the transverse section is located in the middle of the annular seat, and the guide section is located on the lower part of the annular seat. The lower end of the longitudinal section and the upper end of the guide section are connected to the transverse section. The anti-winding part is slidably installed in the guide section. The anti-winding part includes a fixed rod and a rotating rod. The fixed rod is guided and installed in the guide section. The fixed rod can only slide up and down along the guide section and cannot rotate in the guide section. All pull ropes are divided into upper and lower sections. The lower end of the upper half of each pull rope is connected to the upper end of the fixed rod. The middle of the lower end of the fixed rod is provided with a downward-opening rotating mounting hole. A rotating rod is rotatably installed in the rotating mounting hole. The upper end of the lower half of each pull rope is connected to the lower end of the rotating rod. Or / and, also includes ball bearings, with several ball bearings provided on the outer sides of the two semi-cylinders.

8. The coiled tubing drilling centering device according to claim 4, characterized in that, An annular seat is provided between the lower side of the two semi-cylinders and the upper side of the downhole motor. The annular seat has a fifth rope hole for the pull rope to pass through. The fifth rope hole and the axial hollow channel form a rope passage. The middle of the pull rope is provided with an anti-winding part fitted into the rope passage to prevent the pull ropes from getting tangled together. Or / and, the fifth rope threading hole includes a longitudinal section, a transverse section, and a guide section. The longitudinal section is located on the upper part of the annular seat, the transverse section is located in the middle of the annular seat, and the guide section is located on the lower part of the annular seat. The lower end of the longitudinal section and the upper end of the guide section are connected to the transverse section. The anti-winding part is slidably installed in the guide section. The anti-winding part includes a fixed rod and a rotating rod. The fixed rod is guided and installed in the guide section. The fixed rod can only slide up and down along the guide section and cannot rotate in the guide section. All pull ropes are divided into upper and lower sections. The lower end of the upper half of each pull rope is connected to the upper end of the fixed rod. The middle of the lower end of the fixed rod is provided with a downward-opening rotating mounting hole. A rotating rod is rotatably installed in the rotating mounting hole. The upper end of the lower half of each pull rope is connected to the lower end of the rotating rod. Or / and, also includes ball bearings, with several ball bearings provided on the outer sides of the two semi-cylinders.

9. The coiled tubing drilling centering device according to claim 5, characterized in that, An annular seat is provided between the lower side of the two semi-cylinders and the upper side of the downhole motor. The annular seat has a fifth rope hole for the pull rope to pass through. The fifth rope hole and the axial hollow channel form a rope passage. The middle of the pull rope is provided with an anti-winding part fitted into the rope passage to prevent the pull ropes from getting tangled together. Or / and, the fifth rope threading hole includes a longitudinal section, a transverse section, and a guide section. The longitudinal section is located on the upper part of the annular seat, the transverse section is located in the middle of the annular seat, and the guide section is located on the lower part of the annular seat. The lower end of the longitudinal section and the upper end of the guide section are connected to the transverse section. The anti-winding part is slidably installed in the guide section. The anti-winding part includes a fixed rod and a rotating rod. The fixed rod is guided and installed in the guide section. The fixed rod can only slide up and down along the guide section and cannot rotate in the guide section. All pull ropes are divided into upper and lower sections. The lower end of the upper half of each pull rope is connected to the upper end of the fixed rod. The middle of the lower end of the fixed rod is provided with a downward-opening rotating mounting hole. A rotating rod is rotatably installed in the rotating mounting hole. The upper end of the lower half of each pull rope is connected to the lower end of the rotating rod. Or / and, also includes ball bearings, with several ball bearings provided on the outer sides of the two semi-cylinders.

10. A method for straightening coiled tubing drilling, employing the coiled tubing drilling straightening device according to any one of claims 4, 6, and 8, characterized in that it comprises: Connect the coiled tubing drilling centralizer to the bottom end of the coiled tubing drilling centralizer tubing, and lower the coiled tubing drilling centralizer into the wellbore; Start the surface mud pump and inject high-pressure mud into the coiled tubing. The high-pressure mud can drive the downhole motor to rotate and drive the drill bit to achieve drilling operations. During drilling, the two counterweights rotate together with the drill bit. The centrifugal force on the two counterweights is transmitted to the lower end of the upper drive cylinder through the pull rope. The upper drive cylinder moves synchronously towards the lower drive cylinder through the first synchronization structure. The upper drive cylinder and the lower drive cylinder move away from each other in a direction that resists the preload of the elastic expansion joint through the inverted conical outer ring platform and the conical outer ring platform, respectively, until the outer walls of the two semi-cylinders support or abut against the well wall. This provides lateral support for the bottom of the coiled tubing and the drill bit, straightens and fixes the drilling direction of the drill bit, reduces the lateral deviation of the drill bit during drilling, and ensures that the wellbore trajectory coincides with the predetermined target.

Images