WO2023284883A1

WO2023284883A1 - Flexible branch downhole drilling tool

Info

Publication number: WO2023284883A1
Application number: PCT/CN2022/106238
Authority: WO
Inventors: 徐梓辰; 杨忠华
Original assignee: 蓝土地能源技术有限公司
Priority date: 2021-07-16
Filing date: 2022-07-18
Publication date: 2023-01-19
Also published as: CN115613974A; WO2023284901A1

Abstract

A flexible branch downhole drilling tool, comprising a drill bit (5) and a flexible segment. The flexible segment comprises a plurality of power pup joints (2) and a plurality of turning pup joints (3) driven by hydraulic pressure; the adjacent power pup joints are connected by the turning pup joint structures; the flexible segment is mounted at a front end of a rigid drill string (1). Therefore, in the flexible branch downhole drilling tool, the rigid drill string applies a bit pressure for the drill bit to a transfer segment, and the bit pressure is then applied to the drill bit by each power pup joint; the rotational torque is generated by the power pup joints and applied to the drill bit; the bit pressure and the rotational torque are respectively applied to the drill bit independently of each other so that the bit pressure and the rotational torque applied to the drill bit have good controllability; when the turning structures are the turning pup joints, the turning pup joints are disposed between the plurality of power pup joints; each turning pup joint and each power pup joint are relatively short, so that the length of a rigid segment of the whole drilling tool is greatly shortened, and a borehole having a small radius of curvature which is difficult to construct by conventional power drilling tools can be constructed.

Description

A flexible branch drilling tool

technical field

The invention belongs to the technical field of exploration drilling tools, and in particular relates to a flexible branch drilling tool.

Background technique

In oil and natural gas extraction, the development efficiency of oil and gas reservoirs can be significantly improved by drilling branch wells. The branch wells here are branch wellbores connected to the main well, which is equivalent to increasing the channels for oil or gas production, which will naturally improve Development efficiency has obvious advantages in economic benefits, but because branch wells need to reach the oil and gas reservoirs, in the drilling process, branch wells must be bent, which makes drilling difficult and requires special drilling equipment. Drilling equipment needs to be able to drive the drill bit to rotate and drill, and it needs to be able to turn.

Steering drilling technology can artificially control the wellbore trajectory to drill toward the pre-designed target layer. This technology enables the drill bit to bypass obstacles to reach the oil reservoir, and can explore scattered oil reservoirs and heavy oil reservoirs, which is better than traditional vertical wells. For example, in the prior art, the Chinese patent document with the publication number CN2135055Y records a kind of flexible hinged steering power drilling tool for drilling, and the Chinese patent document with the publication number CN2548742Y records a multi-axis drill Among the ball joints, the Chinese patent document whose publication number is CN112814568A records a flexible steering drilling tool, which can be used for steering drilling and is suitable for drilling branch wells.

However, at present, the drilling tools for steerable drilling still have the following deficiencies: one is that the length of the rigid section of the existing conventional steerable drilling tool is longer, and it is difficult to drill a small radius of curvature well section with a larger turning range during the drilling process; The power of some steerable drilling tools will be attenuated, and it is difficult to meet the drilling power for long-distance branch wells.

Contents of the invention

The present invention aims to provide a flexible branch drilling tool to solve the technical problems of small turning range and low drilling power in the prior art.

In order to solve the problems of the technologies described above, the present invention adopts the following technical solutions:

A flexible branch drilling tool is provided, including:

A flexible section, the flexible section includes a multi-section power sub-joint and a multi-section turning sub-section, adjacent power sub-joints are connected by a turning structure, and the multi-section power sub-section is connected to the multi-section turning sub-section ahead;

a transmission sub-joint, which is also connected in front of the foremost power sub-joint through a turning structure;

Drill bit, a power shaft is provided in the power sub-joint, a universal joint transmission device is provided in the turning structure, an output shaft is provided in the transmission sub-joint, the power shaft, universal joint transmission device, output The shafts are connected sequentially, and the drill bit is installed at the front end of the output shaft;

Each of the power sub-joints, each turning structure, the transmission sub-joint and the drill bit is provided with a communicating hydraulic flow channel, and each of the power shafts is provided with a rotor that can be driven by hydraulic pressure to apply rotation to the drill bit. torque.

Preferably, the turning structure is a turning joint, the universal joint transmission device is a universal ball shaft, and each turning joint includes a first shell and a second shell, and the front end of the first shell is correspondingly inserted into the The rear end of the second housing, and a first gap for turning is provided between the front end of the first housing and the corresponding rear end of the second housing, and a sealing ring is provided in the first gap; one end of the universal ball shaft The other end is correspondingly located in the first housing, and the other end is correspondingly located in the second housing.

Preferably, each of the power sub-joints includes a third housing, the power shaft is correspondingly installed in the third housing through bearings, the front end of the third housing is connected to the first housing of the previous turning sub-joint, and the rear end Connect with the second casing of the next turning sub;

Each of the power shaft and the output shaft is hollow, and a first flow hole is provided in the drill bit,

The two ends of the power shaft are respectively provided with connection grooves, the two ends of the universal ball shaft are respectively provided with ball heads, the ball heads are installed in the connection grooves, and the ball head and the connection grooves are arranged along the circumferential direction. There is a second flow hole; a sealing sleeve is connected between the rear end of the power shaft and the front end of the corresponding first housing, and a second gap is provided between the universal ball shaft and the corresponding first housing and second housing , the power shaft, the output shaft, the inner hole of the drill bit, each of the second flow holes, each of the second gaps, and each of the sealing sleeves are connected to form the hydraulic flow channel;

A third gap is provided between the third housing and the corresponding power shaft, and a third flow hole is provided on the wall surface of each power shaft, and the third gap is correspondingly connected to the second gap on the rear side thereof, The fluid in the hydraulic channel can flow into the third gap correspondingly to drive the rotor to rotate.

Preferably, a stator is arranged in the third housing, and the stator is matched with the rotor on the corresponding power shaft to define a hydraulic flow space.

Preferably, the front end of the flexible branch drilling tool is equipped with an attitude measurement module, and the rear end is equipped with a tool face angle measurement module and an information transmission module, and the attitude measurement module and the tool face angle measurement module are connected to the information transmission module.

Preferably, the attitude measurement module includes a well inclination sensor, the tool face angle measurement module includes a magnetometer and/or an acceleration sensor; the information transmission module is a mud pulse generator.

Preferably, the transmission pup joint includes a fourth housing, the output shaft is installed in the fourth housing through a radial bearing set and an axial thrust bearing set; the rear end of the fourth housing is connected to the adjacent turning In the second casing of the pup joint, the rear end of the output shaft is provided with a connection groove, and the universal ball shaft adjacent to the output shaft is correspondingly connected in the connection groove; the attitude measurement module is arranged inside the fourth casing The front end, the tool face angle measurement module and the information transmission module are arranged in one of the turning joints.

Preferably, an eccentric centralizing wing is provided on the outside of the fourth shell or the fourth shell is a fourth shell with a bent angle.

Preferably, the rotor includes multiple flat impellers.

Preferably, it also includes a rigid drill string, the rigid drill string is hollow, the flexible section is installed at the front end of the rigid drill string, and the rigid drill string is used to apply WOB to the flexible section.

Compared with prior art, the beneficial effect of the present invention is:

1. The flexible branch drilling tool includes a flexible section. The flexible section includes multiple power nipples driven by hydraulic pressure. Adjacent power nipples are connected by turning nipples. The flexible section is installed at the front end of the rigid drill string. Therefore, the flexible For branch drilling tools, the drilling pressure is applied to the drill bit by the rigid drill string, and the rotary torque is applied to the drill bit by each power sub. The drilling pressure and the rotary torque are applied to the drill bit independently of each other. In series, the torque of each power nipple can be continuously increased from top to bottom, and finally the bottom bit can obtain greater torque.

2. Since the flexible branch drilling tool is equipped with multiple turning nipples and multiple power nipples, each turning nipple and power nipple are relatively short, which greatly shortens the length of the rigid section of the overall drilling tool. It is capable of constructing holes with small curvature radius that are difficult to construct with conventional power drilling tools.

Description of drawings

The accompanying drawings are used to provide a further understanding of the present invention, and constitute a part of the description, and are used together with the embodiments of the present invention to explain the present invention, and do not constitute a limitation to the present invention. In the attached picture:

Fig. 1 is a partial sectional view of an embodiment of the flexible lateral drilling tool of the present invention.

Fig. 2 is a cross-sectional view of the front part of the flexible section in an embodiment of the flexible lateral drilling tool of the present invention.

FIG. 3 is an enlarged view of part A of FIG. 2 .

FIG. 4 is an enlarged view of part B of FIG. 1 .

Fig. 5 is a schematic structural view of another embodiment of the flexible lateral drilling tool of the present invention.

In the figure, each label is shown as: 1. Rigid drill string; 2. Power nipple; 21. Third shell; 22. Power shaft; 221. Connection groove; 222. Universal ball key; 223. Third flow hole; 23. The third gap; 24. The rotor; 26. The stator; 27. The bearing; 3. The turning joint; 31. The first shell; 311. The first outer step; 312. The second outer step; 32. The second shell; 33. Universal ball shaft; 331. Ball head; 34. First clearance; 341. First sealing ring; 342. Second sealing ring; 343. First inner step; 344. Second inner step; 35. Ball seat ;36, sealing sleeve; 37, the second gap; 4, the transmission nipple; 41, the fourth shell; 42, the output shaft; 421, the connecting shaft; 422, the connecting groove; 43, radial bearing group; 44, Axial thrust bearing group; 45. Eccentric righting wing; 5. Drill bit; 51. First flow hole; 6. Hydraulic flow channel; 7. Information transmission module; 71. Surface angle measurement module; 72. Signal line; 73 , Attitude measurement module; 8, Signal subsection.

detailed description

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

A flexible lateral drilling tool, please refer to Figures 1 to 5.

As shown in Figure 1, the flexible branch drilling tool includes a rigid drill string 1 and a flexible section installed at the front end of the rigid drill string 1, wherein the rigid drill string 1 is used to apply WOB to the flexible section, where the WOB is Refers to the forward drilling pressure of the flexible branch drilling tool in the wellbore, and the flexible section can turn to drill curved branch wells.

The flexible section includes multi-section power sub-joints 2 and multi-section turning sub-joints 3. Adjacent power sub-sections 2 are connected by a turning structure. The power sub-sections 2 are used to apply the rotation power of the flexible branch drilling tool. Each turning sub-section 3 all can realize the turning of certain angle range. The front end of the flexible section is provided with a transmission nipple 4, and the rigid drill string 1 is connected to the power nipple 2 in front of the flexible drill pipe formed by the multi-section turning nipple 3 at the rear end, and the driving nipple 4 is connected to the front end through a turning structure Power sub-joint 2 on. The sum of the axial lengths of the multi-section power sub-joint 2 and the multi-section turning sub-joint 3 is greater than the axial length of the pre-drilled branch well.

The front end of the transmission nipple 4 is connected with the drill bit 5. On the one hand, the transmission nipple 4 plays the role of assisting the drill bit 5 to turn, and on the other hand, it plays the role of connecting the drill bit 5 with the power nipple 2 behind. Each power nipple 2 applies The rotating torque is finally transmitted to the drill bit 5 through the transmission nipple 4.

Therefore, in the flexible branch drilling tool of this embodiment, the drilling pressure is applied to the drill bit 5 by the rigid drill string 1, and the rotary torque is applied to the drill bit 5 by each power nipple 2, and the drilling pressure and the rotary torque are applied to the drill bit 5 independently of each other, so that The weight-on-bit and rotational torque applied to the drill bit 5 are well controllable, and the torque of each power sub 2 can be accumulated, and finally the rotational torque transmitted to the drill bit 5 is stronger.

Specifically, as shown in Figure 2 and Figure 3, the turning structure between the power subs is a turning sub, and each turning sub 3 includes a first shell 31 and a second shell 32, and the first shell 31 and the second shell A universal ball shaft 33 is provided in the housing 32, the rear end of the universal ball shaft 33 is correspondingly located in the first housing 31, and the front end is correspondingly located in the second housing 32, the front and rear ends of the universal ball shaft 33 are provided with ball heads 331, Used to connect the front and rear power nipples 2.

The front end of the first casing 31 of the turning nipple 3 is tapered, and the rear end of the second casing 32 corresponds to a tapered interface, so that the front end of the first casing 31 is correspondingly inserted into the rear end of the second casing 32, and the front end of the first casing 31 A first gap 34 for turning is provided between the rear end of the corresponding second housing 32. The first gap 34 is an annular space, and a sealing ring is provided in the first gap 34, including a first sealing ring 341 and a second sealing ring. The ring 342 seals the first gap 34 to prevent leakage of the high-pressure liquid medium circulating inside, and prevent external hydraulic fluid from entering the inside of the first housing 31 and the second housing 32 during drilling.

The front end of the first shell 31 is provided with a first outer step 311 and a second outer step 312, and the rear end of the second shell 32 is provided with a first inner step 343 and a second inner step 344, and the first sealing ring 341 is located on the second inner step 344. Between the second inner step 344 and the second sealing ring 342 is located between the first outer step 311 and the first inner step 343 .

A ball seat 35 is arranged inside the second housing 32, and the front end of the first housing 31 is a spherical shape matched with the ball seat 35, so that the first housing 31 can smoothly swing along the second housing 32, because there is a first gap 34 When the second housing 32 turns relative to the first housing 31, one side of the first sealing ring 341 and the second sealing ring 342 can be compressed and deformed, therefore, the first housing 31 and the second housing 32 can be within a certain angle range For turning, since there are multiple turning joints 3 in the flexible section, each turning joint 3 can turn at a certain angle, so that the flexible section as a whole has a larger turning range.

As shown in Figure 4, each power pup joint 2 includes a third shell 21, the front and rear ends of the third shell 21 are tapered threads, the rear end of the first shell 31 and the front end of the second shell 32 are corresponding tapered threads , so that the front end of the third casing 21 is connected to the first casing 31 of the previous turning sub, and the rear end is connected to the second casing 32 of the following turning sub. In this embodiment, the front and rear ends of the third casing 21 are connected to the corresponding first casing. The first shell 31 and the second shell 32 can be connected by thread.

As shown in Figure 4, each power sub-joint 2 is provided with a power shaft 22, and the power shaft 22 is installed in the third housing 21 through a bearing 27, and the hydraulic medium can flow through the bearing 27, and the two ends of the power shaft 22 are respectively provided with The connection groove 221, the ball head 331 at the end of the universal ball shaft 33 is correspondingly installed in the connection groove 221 through the universal ball key 222, and the universal ball key 222 is connected in the connection groove 221 through a pin shaft structure, a tooth socket or teeth, It is used to transmit torque between the ball head 331 and the connecting groove 221 .

Since the universal ball shaft 33 is installed inside the first shell 31 and the second shell 32, and its two ends are installed in the connection groove 221 on the adjacent power shaft 22 by the ball head 331 through the universal ball key 222, when When the adjacent power shaft 22 deflects, the turning angle of the power shaft 22 is borne by the two ball heads 331, which reduces the wear of the ball head 331 and the connecting groove 221. For example, when the power shaft 22 turns 6°, the power shaft 22 The deflection angles of the ball heads 331 on both sides are respectively 3°, which greatly reduces the wear on the ball heads and the connecting groove 221 .

When the power shaft 22 turns, the first shell 31 of the turning joint 3 swings relative to the second shell 32 .

As shown in Figure 2, the transmission pup joint 4 includes a fourth housing 41, an output shaft 42 is arranged in the fourth housing 41, a drill bit 5 is arranged at the front end of the output shaft 42, and the output shaft 42 passes through a radial bearing group 43 and an axial thrust The bearing group 44 is installed in the fourth housing 41 , the radial bearing group 43 includes a plurality of ball bearings, and the axial thrust bearing group 44 can be composed of an axial sliding bearing or a thrust ball bearing group. The rear end of the fourth housing 41 is threadedly connected to the second housing 32 of the adjacent turning nipple. The output shaft 42 includes a connecting shaft portion 421 at the rear end, and a connecting groove 422 is provided at the end of the connecting shaft portion 421. The ball head 331 of the adjacent universal ball shaft 33 is correspondingly connected in the connection groove 422 to realize the connection between the transmission nipple 4 and the flexible section. It is known that the front end of the rigid drill string 1 is threadedly connected to the rear end of the first casing corresponding to the turning sub, and will not be described in detail here.

In this embodiment, the rigid drill string 1 is hollow, and as shown in FIG. 331 and the corresponding connection groove are provided with a second flow hole (not shown in the figure) along the circumference, and a sealing sleeve 36 is connected between the rear end of the power shaft 22 and the corresponding front end of the first housing 31, and the sealing sleeve 36 is Flexible, and the second gap 37 is provided between the universal ball shaft 33 and the corresponding first housing 31, the second housing 32, the second gap 37 is an annular space, therefore, in combination with the rigid drill as shown in Figure 2 The column 1, each power shaft 2, the output shaft 42, the inner hole of the drill bit 5, each second flow hole, each second gap 37, and each sealing sleeve 36 are connected to form the hydraulic flow channel 6 indicated by the arrow in Fig. 2 , from The high-pressure hydraulic medium injected into the end of the rigid drill string 1 can flow forward along the hydraulic channel 6 .

As shown in FIG. 4 , each power shaft 22 is provided with a rotor 24 that can be driven by hydraulic pressure. The rotor 24 is connected to the power shaft 22 as a fixed connection or integrally formed. When the high-pressure liquid medium is flushing, the rotor 24 can drive the power shaft 22. Rotate to apply a rotational torque to the drill bit 5. The rotor 24 includes multiple sets of blades, and each set of blades includes multiple flat impellers, which is conducive to shortening the length of each power sub, thereby greatly reducing the turning radius of the flexible branch drilling tool. The impellers are arranged at a certain angle , so that the high-pressure drilling fluid flows along the diversion direction to produce oblique scour to the impeller. Since the impeller and the power shaft 22 are fixed, under the action of the scouring force, the impeller will rotate around the power shaft 22 and drive the power shaft 22 to turn, converting the high-pressure fluid energy into mechanical energy for drilling.

Further, as shown in FIG. 4 , a third gap 23 is provided between the third shell 21 and the power shaft 22 inside it. The third gap 23 is an annular space, and a third gap 23 is provided on the wall surface of each power shaft 22 . The flow hole 223, therefore, the high-pressure liquid medium circulating in the hydraulic channel 6 can enter the third gap 23 through the third flow hole 223 to drive the rotor 24 to rotate, and the end of the third gap 23 is correspondingly connected to the second gap on the rear side thereof 37, so that the fluid in the hydraulic channel 6 can continuously flow into the third gap 23 to drive the rotor to rotate.

Further, as shown in FIG. 4, a stator 26 is arranged in the third housing 21, and the stator 26 is matched with the rotor 24 on the internal power shaft 22 to define a hydraulic flow space, which includes several and the liquid flow channel between the rotor 24, so that the limited space of the liquid medium between the stator and the rotor is limited to wash the rotor 24 intensively, and the torque of the rotor 24 is larger.

As shown in Figure 2, an eccentric centralizing wing 45 is provided on the outer wall of the transmission nipple 4. When the flexible branch drilling tool is drilling, the eccentric centralizing wing 45 will apply an eccentric thrust to the drill bit 5. Therefore, when the rigid drill string 1 applies During weight-on-bit, it can meet the needs of deflection drilling. During deflection, the drill bit 5 will deflect with the turning nipple at the front end as the deflection center and the contact point between the eccentric righting wing 45 and the well wall as the fulcrum.

When the flexible branch drilling tool is drilling, the flexible branch drilling tool is rotated at the wellhead end to adjust the direction of the tool face of the flexible branch drilling tool to realize turning and steering. In other embodiments, the front end of the fourth housing of the transmission nipple may also be designed with a curved angle for turning guidance.

Since the output shaft 42 and the corresponding ball head are hinged, when the drill bit 5 is deflected, the bending moment generated by the drill bit 5 is avoided from being transmitted to the upper part of the drill tool, so that the drill bit 5 can be more easily formed by the eccentric righting wing 45. The fulcrum deflects in the direction of the guide. At the same time, because the drill bit 5 eliminates the transmission of the bending moment, when the drill bit 5 is deflected, the radius of the arc formed by the deflection center point where the frontmost turning nipple is located and the fulcrum where the eccentric righting wing 45 is located is as short as possible to improve manufacturing. oblique performance purposes.

Further, as shown in FIG. 1, the front end of the flexible branch drilling tool is provided with an attitude measurement module 73, and the rear end is provided with a tool face angle measurement module 71 and an information transmission module 7. The attitude measurement module 73 and the tool face angle measurement module 71 signal Connected to the information transmission module 7, wherein, in this embodiment, the attitude measurement module 73 is arranged at the front end inside the fourth shell 41, and the tool face angle measurement module 71 and the information transmission module 7 are arranged at the signal pup joint adjacent to the rigid drill string 1 8, the signal sub-joint 8 is similar in structure to the turning sub-joint. The tool face angle measurement module 71 is connected to the information transmission module 7 through the signal line 72, and the attitude measurement module 73 is also connected to the information transmission module 7 through the internal signal line (not shown in the figure). Pass Module 7.

The attitude measurement module 73 includes a well inclination sensor, the tool face angle measurement module 71 includes a magnetometer or an acceleration sensor; the information transmission module 7 is a mud pulse generator. The inclination angle sensor here is used to measure the inclination angle of the wellbore, which is the angle between the central axis of a point in the wellbore and the earth's plumb line; the magnetometer and acceleration sensor are used to measure the inclination angle of the flexible branch drilling The tool face angle of the tool, the tool face angle is the angle of the tool face during the build-up process, which can be used to assist in controlling the guidance; the mud pulse generator can communicate with the ground equipment, and is used to connect the attitude measurement module and the tool face angle measurement module The measured information is sent to the wellhead.

As shown in Figure 5, in another embodiment, the tool face angle measurement module 71 can also be arranged in the turning joint 3 in the middle of the flexible section, and the attitude measurement module 73 at the front end and the tool face angle measurement module 71 in the middle pass through The signal line 72 is electrically connected to the information transfer module 7 .

During construction, the flexible section of the flexible branch drilling tool is connected to the well by the rigid drill string 1, and the rigid drill string 1 can transmit the drilling pressure required for drilling to the flexible section. The rigid drill string 1, The power shaft 22 in each power sub-joint 2, the universal ball shaft 33 in each turning sub-joint 3, and the output shaft 42 in the transmission sub-joint 4 are sequentially connected, and the drill bit 5 is installed at the front end of the output shaft 42, so the rigidity The drill string 1, each power sub-joint 2, each turning sub-joint 3, transmission sub-joint 4 and drill bit 5 are provided with a hydraulic passage 6 communicating with each other, and each power shaft 22 is provided with a rotor 24 that can be driven by hydraulic pressure, so , the hydraulic medium such as high-pressure water can be injected into the rigid drill string 1, the hydraulic medium circulates along the hydraulic flow channel 6, and the hydraulic medium in the hydraulic flow channel 6 enters the third gap 23 where the rotor 24 is located through the third flow hole 223, The rotors 24 are rotated, and the accumulated torque of each rotor 24 drives the drill bit 5 to rotate. The high-pressure water flows out from the first flow hole 51 in the drill bit 5 and scours the working surface of the wellbore, and finally flows out from the wellhead.

Since the flexible branch drilling tool is equipped with multiple turning nipples 3 and multiple power nipples 2, each power nipple 2 can provide independent torque. Therefore, under the premise of meeting the drilling power demand, The turning sub 3 and the power sub 2 are relatively short, which greatly shortens the length of the rigid section of the overall drilling tool. In oil and gas development, the flexible branch drilling tool can be transmitted to the high-curvature branch wellbore through the turning sub 3, or the flexible branch drilling tool can be sent to the high-curvature branch well section to realize the branch well drilling operation, so that the small curvature that is difficult to operate with conventional power drilling tools can be realized. radius wellbore for construction.

It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is a relationship between these entities or operations. any such actual relationship or order exists between them. Furthermore, the term "comprises", "comprises" or any other variation thereof is intended to cover a non-exclusive inclusion such that a process, method, article, or apparatus comprising a set of elements includes not only those elements, but also includes elements not expressly listed. other elements of or also include elements inherent in such a process, method, article, or device.

Although the embodiments of the present invention have been shown and described, those skilled in the art can understand that various changes, modifications and substitutions can be made to these embodiments without departing from the principle and spirit of the present invention. and modifications, the scope of the invention is defined by the appended claims and their equivalents.

Claims

A flexible branch drilling tool, characterized in that it comprises:

A flexible section, the flexible section includes a plurality of power sub-joints, and adjacent power sub-joints are connected by a turning structure;

a transmission sub-joint, which is also connected in front of the foremost power sub-joint through a turning structure;

Drill bit, a power shaft is provided in the power sub-joint, a universal joint transmission device is provided in the turning structure, an output shaft is provided in the transmission sub-joint, the power shaft, universal joint transmission device, output The shafts are connected sequentially, and the drill bit is installed at the front end of the output shaft;

Each of the power sub-joints, each turning structure, the transmission sub-joint and the drill bit is provided with a communicating hydraulic flow channel, and each of the power shafts is provided with a rotor that can be driven by hydraulic pressure to apply rotation to the drill bit. torque.
The flexible branch drilling tool according to claim 1, wherein the turning structure is a turning sub, the universal transmission device is a universal ball shaft, and each of the turning subs includes a first housing and a second casing. The housing, the front end of the first housing is correspondingly inserted into the rear end of the second housing, and a first gap for turning is provided between the front end of the first housing and the corresponding rear end of the second housing, in the first gap A sealing ring is provided; one end of the universal ball shaft is correspondingly located in the first housing, and the other end is correspondingly located in the second housing.
The flexible branch drilling tool according to claim 2, wherein each of the power nipples includes a third casing, the power shaft is correspondingly installed in the third casing through a bearing, and the front end of the third casing is connected to the third casing. The first casing of the previous turning sub is connected, and the rear end is connected with the second casing of the following turning sub;

Each of the power shaft and the output shaft is hollow, and a first flow hole is provided in the drill bit,

The two ends of the power shaft are respectively provided with connection grooves, the two ends of the universal ball shaft are respectively provided with ball heads, the ball heads are installed in the connection grooves, and the ball head and the connection grooves are arranged along the circumferential direction. There is a second flow hole; a sealing sleeve is connected between the rear end of the power shaft and the front end of the corresponding first housing, and a second gap is provided between the universal ball shaft and the corresponding first housing and second housing , the power shaft, the output shaft, the inner hole of the drill bit, each of the second flow holes, each of the second gaps, and each of the sealing sleeves are connected to form the hydraulic flow channel;

A third gap is provided between the third housing and the corresponding power shaft, and a third flow hole is provided on the wall surface of each power shaft, and the third gap is correspondingly connected to the second gap on the rear side thereof, The fluid in the hydraulic channel can flow into the third gap correspondingly to drive the rotor to rotate.
The flexible branch drilling tool according to claim 3, wherein a stator is arranged in the third casing, and the stator is matched with the rotor on the corresponding power shaft to define a hydraulic flow space.
The flexible branch drilling tool according to claim 1, characterized in that: the front end of the flexible branch drilling tool is provided with an attitude measurement module, and the rear end is provided with a tool face angle measurement module and an information transmission module, the attitude measurement module, the tool face The angle measurement module is signal connected to the information transfer module.
The flexible branch drilling tool according to claim 5, characterized in that: the attitude measurement module includes a well inclination angle sensor, the tool face angle measurement module includes a magnetometer and/or an acceleration sensor; the information transmission module is a mud pulse generator.
The flexible branch drilling tool according to claim 6, wherein the transmission nipple includes a fourth housing, and the output shaft is installed in the fourth housing through a radial bearing set and an axial thrust bearing set The rear end of the fourth casing is connected to the second casing of the adjacent turning joint, the rear end of the output shaft is provided with a connection groove, and the universal ball shaft adjacent to the output shaft is correspondingly connected in the connection groove; The attitude measurement module is arranged at the inner front end of the fourth housing, and the tool face angle measurement module and information transmission module are arranged in one of the turning joints.
The flexible branch drilling tool according to claim 1, characterized in that: the outer side of the fourth shell is provided with an eccentric centralizing wing or the fourth shell is a fourth shell with an angle.
The flexible branch drilling tool according to claim 1, wherein the rotor comprises a plurality of flat impellers.
The flexible branch drilling tool according to claim 1, further comprising a rigid drill string, the rigid drill string is hollow, the flexible section is installed at the front end of the rigid drill string, and the rigid drill string is used to The flexible segment applies weight on bit.