CN118167202A - A rotary steerable drilling system - Google Patents

Abstract

The application discloses a rotary steering drilling system, which relates to the technical field of drilling equipment and comprises an upper joint, a lower joint and a shell, wherein the upper joint and the lower joint are connected to two ends of the shell, and the central aperture of the lower joint is smaller than that of the shell; the novel rotary shaft comprises a shell, and is characterized in that a rotating central shaft rod is arranged in the shell, a pushing component is circumferentially arranged on the outer wall of the shell, a communicating piece is sleeved outside the central shaft rod, the communicating piece is arranged in guide holes communicated with the pushing component in one-to-one correspondence, radial flow holes are formed in the central shaft rod along the direction perpendicular to an axis, and the radial flow holes can be communicated with the guide holes alternately along with rotation of the central shaft rod. The application can steer the drill bit along different directions through the plurality of groups of pushing and leaning components arranged in the circumferential direction, and has the advantages of simple structure, convenient control and the like.

Description

A rotary steerable drilling system

Technical Field

The present application relates to the technical field of drilling equipment, and in particular to a rotary steerable drilling system.

Background technique

In oil drilling projects, for some oil fields that are restricted by geographical location or in the late stage of development, it is usually necessary to develop ultra-deep wells, high-difficulty directional wells, large-reach wells and long-distance horizontal wells to obtain oil and gas deep in the formation. In order for the drill bit to reach a specific location, it is necessary to guide the direction of the drill bit. The core of rotary steerable drilling technology is the rotary steerable drilling system. It mainly consists of a downhole rotary automatic steerable drilling system, a ground monitoring system and a two-way communication technology that connects the above two parts. It has the characteristics of low friction and torsional resistance during drilling, high drilling speed, low cost, short well construction period, smooth wellbore trajectory, easy control and can extend the length of the horizontal section.

In the prior art, Bakerhughes' AutoTrack Curve rotary steerable tool and Schl umberger's PD Archer rotary steerable tool are representative. Bakerhughes' AutoTrack Curve rotary steerable tool is driven by hydraulic drive. By precisely controlling three sets of highly integrated and independent motor hydraulic pump modules, hydraulic oil is used to push the cylinder and its wings against the well wall, so as to achieve overall bending deformation of the upper part of the steerable tool to change the direction of the drill bit. Schl umberger's PD Archer rotary steerable tool is driven by mud pressure difference. The piston is driven by using a normally open disc valve to distribute the flow, and then the piston drives the palm to push against the well wall to change the direction of the drill bit.

Both of the above-mentioned rotary steerable tools have complex structures, resulting in high manufacturing and maintenance costs.

Summary of the invention

The main purpose of the present application is to provide a rotary steerable drilling system, aiming to solve the problem of high manufacturing and maintenance costs caused by the complex structure of mainstream rotary steerable tools in the prior art.

The technical solutions adopted in this application are as follows:

A rotary steerable drilling system comprises an upper joint, a lower joint and a shell, wherein the upper joint and the lower joint are connected to two ends of the shell, and the central aperture of the lower joint is smaller than the central aperture of the shell;

Among them, a rotating central shaft is arranged in the shell, a pushing assembly is arranged circumferentially on the outer wall of the shell, a connecting piece is sleeved outside the central shaft, and the connecting piece is arranged in the guide holes that are connected one by one to the pushing assembly. The central shaft is provided with radial flow holes in a direction perpendicular to the axis, and the radial flow holes can be alternately connected with the guide holes as the central shaft rotates.

Optionally, the pushing component includes:

Radial side holes, the radial side holes are circumferentially arrayed on the outer wall of the shell;

A T-shaped push rod, the T-shaped push rod is slidably disposed in the radial side hole and is pushed outward by hydraulic pressure; and

A return spring is arranged in the radial side hole and is used for returning the T-shaped push rod to its original position after pressure relief.

Optionally, a limit block is provided on one side of the radial side hole outside the shell.

Optionally, the connecting piece includes:

A connecting sleeve, the connecting sleeve is sleeved outside the central shaft, and an outer wall of the connecting sleeve is circumferentially provided with an outwardly protruding connector, and the connector is inserted into the radial side hole;

The damping seal is symmetrically arranged on the inner side walls at both ends of the connecting sleeve and is closely attached to the outer wall of the central shaft.

Optionally, the damping seal comprises:

A first sealing ring groove, wherein the first sealing groove is arranged on the inner wall of the connecting sleeve;

a second sealing ring groove, the second sealing ring groove being disposed on the outer wall of the central shaft and corresponding to the first sealing ring groove;

A damping spring, wherein the damping spring is circumferentially arrayed in the first sealing ring groove;

a connecting plate, the connecting plate being annular and fixedly connected to the damping spring; and

A sealing ring, wherein the sealing ring is fixedly connected to the connecting plate, and the sealing ring is located in the first sealing ring groove and the second sealing ring groove at the same time.

Optionally, a driving member for driving the central shaft to rotate is disposed in the shell, and the driving member includes a driving motor, and a driving gear is disposed at the output end of the driving motor. A driven gear is sleeved on the central shaft, and the driven gear is meshed with the driving gear.

Optionally, a main shaft is also provided inside the shell, the main shaft is provided with an internal flow channel connected to the upper joint, the internal flow channel is drained into the center hole of the shell, the main shaft is provided with guide vanes, a stator is provided inside the main shaft, a rotor is provided outside the main shaft, and rotating blades are provided on the rotor.

Optionally, the main shaft is also packaged with an integrated control board, on which a rectification and voltage stabilization circuit, an attitude measurement sensor, an azimuth gamma sensor, a motor drive board and a main controller are integrated.

Optionally, a pressure relief hole is further provided on the shell, and a pressure relief valve is provided at the pressure relief hole.

Optionally, the shell is detachably connected to the upper joint and the lower joint, and a sealing structure is provided between the shell and the upper joint and the lower joint.

Compared with the prior art, the beneficial effects of this application are:

A rotary steerable drilling system proposed in an embodiment of the present application has a simpler structure than the mainstream steerable tool, and includes an upper joint, a lower joint and a shell. The central aperture of the lower joint is smaller than the central aperture of the shell, thereby forming a pressure difference between the shell and the lower joint. At the same time, a rotating central shaft is arranged inside the shell, and a circumferential array of pushing components is arranged on the outer peripheral wall of the shell. A connecting piece is used to connect the radial flow holes of the central shaft to the pushing components through the guide holes. During the rotation of the central shaft, the drilling hydraulics uses the pressure difference to push a certain pushing component outward against the inner wall of the drilling well, thereby generating a pushing force to turn the drill bit. Multiple groups of pushing components arranged circumferentially can turn the drill bit in different directions.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic structural diagram of a rotary steerable drilling system provided in an embodiment of the present application at one viewing angle;

Figure 2 is an enlarged view of point A in Figure 1;

FIG3 is an enlarged view of point B in FIG1 .

Description of the reference numerals in the accompanying drawings:

1-upper joint, 2-shell, 3-lower joint, 4-center shaft, 401-axial guide hole, 402-radial flow hole, 5-connecting piece, 501-connecting sleeve, 502-guide hole, 503-damping spring, 504-connecting plate, 505-sealing ring, 6-pushing assembly, 601-radial side hole, 602-T-type pushing rod, 603-reset spring, 604-limiting block, 7-driving motor, 8-driving gear, 9-driven gear, 10-main shaft, 11-internal flow channel, 12-guide vane, 13-rotor, 14-rotating blade, 15-stator, 16-integrated control board, 17-pressure relief hole, 18-pressure relief valve, 19-sealing structure.

Detailed ways

The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

It should be noted that all directional indications in the embodiments of the present application (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

In this application, unless otherwise clearly specified and limited, the terms "connection", "fixation", etc. should be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present application, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the meaning of "and/or" appearing in the full text includes three parallel schemes. Taking "A and/or B" as an example, it includes scheme A, or scheme B, or a scheme that satisfies both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in the field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by this application.

Referring to Figures 1 to 3, the embodiment of the present application provides a rotary steerable drilling system, comprising an upper joint 1, a lower joint 3 and a housing 2, wherein the upper joint 1 and the lower joint 3 are connected to both ends of the housing 2, and the central aperture of the lower joint 3 is smaller than the central aperture of the housing 2. A rotating central shaft 4 is provided in the housing 2, a push assembly 6 is provided in the circumferential direction of the outer wall of the housing 2, a connecting piece 5 is provided on the outer surface of the central shaft 4, and the connecting piece 5 is provided in a guide hole 502 that is connected to the push assembly 6 in a one-to-one correspondence, and the central shaft 4 is provided with a radial flow hole 402 in a direction perpendicular to the axis, and the radial flow hole 402 can alternately connect with the guide hole 502 as the central shaft 4 rotates.

A rotary steerable drilling system proposed in an embodiment of the present application has a simpler structure than the mainstream steerable tool, and includes an upper joint 1, a lower joint 3 and a shell 2. The central aperture of the lower joint 3 is smaller than the central aperture of the shell 2, so as to form a pressure difference between the shell 2 and the lower joint 3. At the same time, a rotating central shaft 4 is arranged inside the shell 2, and a circumferential array of push-against assemblies 6 is arranged on the outer peripheral wall of the shell 2. The radial flow holes 402 of the central shaft 4 are connected to the push-against assemblies 6 through the guide holes 502 by means of a connecting piece 5. During the rotation of the central shaft 4, the drilling hydraulic pressure is used to push a certain push-against assemblies 6 outward against the inner wall of the drilling well by means of the pressure difference, thereby generating a push-against force to turn the drill bit. The circumferentially arranged multiple groups of push-against assemblies 6 can turn the drill bit in different directions.

Specifically:

As shown in FIG. 1 , the two ends of the shell 2 form an inwardly concave step-type connection part, and a connecting internal thread is prefabricated inside the step-type connection part. The corresponding upper joint 1 and lower joint 3 form a connection end protruding outward, and an external thread is prefabricated, so that the shell 2 is detachably connected with the upper joint 1 and the lower joint 3 by threaded connection. The upper joint 1, the shell 2, and the lower joint 3 are provided with interconnected central holes along the axial direction, and the drilling hydraulic pressure flows through the central hole. In order to form a sealed connection between the shell 2 and the upper joint 1 and the lower joint 3, a sealing structure 19 is deliberately provided between the shell 2 and the upper joint 1 and the lower joint 3. As a general rule, the sealing structure 19 is mostly a sealing ring, and multiple groups are provided along the axial direction to increase the sealing performance.

In the above, as shown in FIG. 1 and FIG. 2 , a ring platform is formed on the inner wall of the center hole of the housing 2 along the axis, and the ring platform divides the interior of the housing 2 into an upper hole area and a lower hole area. The central shaft 4 is located in the lower hole area, and an axial hole is arranged in the center of the ring platform. The central shaft 4 is installed in the axial hole through a bearing. An axial guide hole 401 is arranged through the central shaft 4 along the axial direction, and the axial guide hole 401 is used to circulate the drilling hydraulic pressure. The central shaft 4 is provided with a single radial flow hole 402 in a direction perpendicular to the axis, and the central hole diameter of the lower joint 3 is larger than the inner diameter of the axial guide hole 401, so that a pressure difference is formed between the interior of the central shaft 4 and the exterior of the upper joint 1, so that the drilling hydraulic pressure can flow out from the radial flow hole 402. At the same time, it is not difficult to understand that in order to prevent the internal pressure of the drill bit from being too high, as shown in FIG. 1 , a pressure relief hole 17 is also arranged on the side wall of the housing 2, and a pressure relief valve 18 is installed in the pressure relief hole 17, and the pressure relief valve 18 is used to relieve pressure to avoid excessive pressure inside the drill bit.

In one embodiment, in order to realize the rotation of the central shaft 4, as shown in FIG1 , a driving member for rotating the central shaft 4 is installed on the housing 2, and the driving member includes a driving motor 7, a driving gear 8 and a driven gear 9. The driving motor 7 is fixed on the housing 2, the driving gear 8 is fixedly sleeved on the output end of the driving motor 7, and the driven gear 9 is fixedly sleeved on the central shaft 4, and the driving gear 8 is meshed with the driven gear 9. It can be imagined that the driving motor 7 drives the driving gear 8 to rotate, and the meshing transmission of the driving gear 8 and the driven gear 9 is used to rotate the central shaft 4, so that the only radial flow hole 402 rotates with the central shaft 4 and is alternately connected with the guide hole, and the drilling hydraulic pressure enters the correspondingly connected push assembly 6 under the action of the pressure difference, so that the push assembly 6 is pressed against the inner wall of the wellbore, thereby applying a reverse push force to deflect the drill bit.

In this embodiment, as shown in FIG. 1 and FIG. 2 , the push assembly 6 includes a radial side hole 601, a T-shaped push rod 602, and a return spring 603. Among them, the side wall of the housing 2 is provided with a plurality of through radial side holes 601 in a circumferential array, and the lateral side holes correspond to the guide holes 502 one by one. The T-shaped push rod 602 is movably arranged in the radial side hole 601, and the cross beam end of the T-shaped push rod 602 is located on one side of the connecting piece 5 and this section is in the shape of a piston head, which is completely fitted with the inner wall of the radial side hole 601, and the vertical beam end of the T-shaped push rod 602 can extend and be received in the radial side hole 601. Further, in order to prevent the T-shaped push rod 602 from sliding out of the radial side hole 601, a limiting block 604 is provided at an end portion of the radial side hole 601 located on the outer side wall of the housing 2. It can be imagined that the setting of the limiting block 604 makes the outer port side of the radial side hole 601 close, and the T-shaped push rod 602 is blocked by the limiting block 604 and cannot slide out. At the same time, a reset spring 603 is sleeved on the vertical beam of the T-type push rod 602, and the reset spring 603 abuts between the limit block 604 and the vertical beam of the T-type push rod 602. Based on the structural design of the push assembly 6, it can be imagined that when the drilling hydraulic pressure is led from the inside of the central shaft 4 through the axial guide hole 401, the radial flow hole 402 to the guide hole 502 to the radial side hole 601, the T-type push rod 602 moves outward under the action of the drilling hydraulic pressure and abuts against the inner wall of the well. With the continuous action of the drilling hydraulic pressure, the T-type push rod 602 applies a reverse thrust to the drill bit, thereby turning the drill bit. Since a plurality of push assemblies 6 are circumferentially arranged on the side wall of the housing 2, when it is necessary to control the drill bit to rotate in a set direction, the central shaft 4 is driven to rotate by the driving motor 7, so that the radial flow hole 402 is connected with the guide hole 502 on the opposite side of the turn, thereby realizing the rotation of the drill bit in the set direction. When the drilling hydraulic pressure is restored, the T-shaped push rod 602 moves toward the inside of the radial side hole 601 under the action of the reset spring 603 to complete the reset.

Meanwhile, in the above embodiment, as shown in Fig. 1 and Fig. 2, the connecting member 5 includes a connecting sleeve 501 and a damping seal, the connecting sleeve 501 is sleeved outside the central shaft 4, and the central shaft 4 can rotate inside the connecting sleeve 501. The outer wall of the connecting sleeve 501 is circumferentially provided with a connector protruding outward, the connector corresponds to the radial side hole 601 one by one, and the connector is interference-inserted in the radial side hole 601, when the central shaft 4 rotates, the only radial flow hole 402 corresponds to a certain radial side hole 601, so that the central shaft 4, the connecting member 5 and the radial side hole 601 are connected.

The damping seals are symmetrically arranged on the inner side walls at both ends of the connecting sleeve 501 and are closely attached to the outer wall of the central shaft 4, and the radial flow holes 402 are located between the damping seals. Specifically, the damping seal includes a first sealing ring groove, a second sealing ring groove, a damping spring 503, a connecting plate 504 and a sealing ring 505. Among them, the first sealing groove is arranged on the inner wall of the connecting sleeve 501, and the second sealing ring groove is arranged on the outer wall of the central shaft 4 and corresponds to the first sealing ring groove; multiple damping springs 503 are circumferentially arrayed and fixed in the first sealing ring groove, and the connecting plate 504 is annular and fixedly connected to the damping spring 503; the sealing ring 505 is fixedly bonded to the connecting plate 504, and the sealing ring 505 is simultaneously located in the first sealing ring groove and the second sealing ring groove.

It can be imagined that based on the structural design of the damping seal, the sealing ring 505 always remains in contact with the first sealing ring groove and the second sealing ring groove under the action of the damping spring 503, thereby forming a seal for the gap between the central shaft 4 and the connecting sleeve 501. At the same time, when the central shaft 4 needs to rotate, the damping spring 503 is slightly deformed by force but does not affect the seal, providing space for the rotation of the central shaft 4, thereby ensuring that the central shaft 4 can rotate smoothly. It can be seen that the damping seal not only has a good sealing effect, but also does not affect the rotation of the central shaft 4.

Based on the above content, the rotary steerable drilling system provided in the embodiment of the present application implements the working principle of rotary steering as follows:

Since the central apertures of the housing 2 and the central shaft 4 are larger than the central aperture of the lower joint 3, a pressure difference is formed between the interior of the housing 2 and the lower joint 3. When the drilling hydraulic pressure enters the interior of the housing 2, part of the drilling hydraulic pressure flows out from the interior of the central shaft 4 through the lower joint 3. At the same time, due to the pressure difference, part of the drilling hydraulic pressure will enter the radial side hole 601 along the interior of the central shaft 4 from the radial flow hole 402 through the guide hole 502 connected to the radial flow hole 402. The drilling hydraulic pressure will push the T-type push rod 602 outward, and the T-type push rod 602 will press against the inner wall of the well to apply reverse thrust to the drill bit, thereby guiding the drill bit to complete the turn. After waiting for the turn to be completed, the drilling hydraulic pressure continues to increase, and the pressure relief valve 18 releases pressure. After the pressure is released, the reset spring 603 drives the T-type push rod 602 to complete the reset.

In the above, since a plurality of push-against assemblies 6 are circumferentially arranged on the shell 2, driven by the driving motor 7, the central shaft 4 rotates so that the radial flow hole 402 can be rotated to any position to connect with a certain guide hole 502, so that the corresponding side push-against assemblies 6 can be extended outward, thereby enabling the drill bit to be turned in different directions.

In a preferred embodiment, as shown in Figures 1 and 3, a main shaft 10 is further provided inside the shell 2, and the main shaft 10 is threadedly connected to the upper joint 1. The main shaft 10 is provided with an internal flow channel 11 that is connected to the upper joint 1, and the internal flow channel 11 drains the drilling hydraulic pressure to the inside of the shell 2. A guide vane 12 is provided on the main shaft 10, and a stator 15 is provided inside the main shaft 10, and a coil is wound on the stator 15. A rotor 13 is provided outside the main shaft 10, and a rotational connection is formed between the rotor 13 and the main shaft 10 through a bearing. The rotor 13 is a permanent magnet and a rotating blade 14 is provided on the rotor 13, wherein the guide blade 12 and the rotating blade 14 are both spiral blades, the guide blade 12 is spirally arranged in a clockwise direction, and the rotating blade 14 is spirally arranged in a counterclockwise direction.

At the same time, an integrated control board 16 is packaged inside the main shaft 10 , and the integrated control board 16 integrates a rectifier and voltage stabilization circuit, a posture measurement sensor, an orientation gamma sensor, a motor drive board and a main controller.

When the annular fluid flows to the guide vane 12 of the main shaft 10, the guide vane 12 is fixed, and the fluid flow direction will change, which is conducive to pushing the rotating blades 14 of the rotor 13 below to make the rotor 13 start to rotate. The rotation of the rotor 13 with permanent magnets will generate a changing magnetic field, so that the stator 15 with coils inside will generate electrical energy and transmit it to the integrated control board 16. The integrated control board 16 first converts the AC power generated by the stator 15 into DC power for use by other electronic components through a rectifier and voltage stabilization circuit; the attitude measurement sensor and the azimuth gamma sensor collect the current position information of the tool, and the main controller analyzes and processes the position information, and then sends the output signal to the motor drive board, thereby controlling the rotation angle of the drive motor 7, thereby controlling the steering of the drill bit.

In summary, the present application provides a rotary steerable drilling system, comprising an upper joint 1, a lower joint 3 and a housing 2, wherein the upper joint 1 and the lower joint 3 are connected to both ends of the housing 2, and the central aperture of the lower joint 3 is smaller than the central aperture of the housing 2. A rotating central shaft 4 is provided in the housing 2, a push assembly 6 is provided circumferentially on the outer wall of the housing 2, a connecting piece 5 is provided on the outer surface of the central shaft 4, and the connecting piece 5 is provided on the guide hole 502 which is connected to the push assembly 6 in a one-to-one correspondence, and the central shaft 4 is provided with a radial flow hole 402 in a direction perpendicular to the axis, and the radial flow hole 402 can be alternately connected with the guide hole 502 as the central shaft 4 rotates.

Based on the above scheme, compared with the mainstream guiding tool, the present application has a simpler structure, including an upper joint 1, a lower joint 3 and a shell 2. The central aperture of the lower joint 3 is smaller than the central aperture of the shell 2, so as to form a pressure difference between the shell 2 and the lower joint 3. At the same time, a rotating central axis 4 is arranged inside the shell 2, and a circumferential array of pushing components 6 are arranged on the outer peripheral wall of the shell 2. The radial flow hole 402 of the central axis 4 is connected to the pushing component 6 through the guide hole 502 by a connecting piece 5. During the rotation of the central axis 4, the drilling hydraulic pressure is used to push a certain pushing component 6 outward against the inner wall of the drilling well, thereby generating a pushing force to turn the drill bit. Multiple groups of pushing components 6 arranged circumferentially can make the drill bit turn in different directions.

The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims (10)

1. A rotary steerable drilling system, characterized in that it comprises an upper joint, a lower joint and a shell, wherein the upper joint and the lower joint are connected to two ends of the shell, and the central aperture of the lower joint is smaller than the central aperture of the shell; Among them, a rotating central shaft is arranged in the shell, a pushing assembly is arranged circumferentially on the outer wall of the shell, a connecting piece is sleeved outside the central shaft, and the connecting piece is arranged in the guide holes that are connected one by one to the pushing assembly. The central shaft is provided with radial flow holes in a direction perpendicular to the axis, and the radial flow holes can be alternately connected with the guide holes as the central shaft rotates. 2. The rotary steerable drilling system according to claim 1, wherein the pushing assembly comprises: Radial side holes, the radial side holes are circumferentially arrayed on the outer wall of the shell; A T-shaped push rod, the T-shaped push rod is slidably disposed in the radial side hole and is pushed outward by hydraulic pressure; and A return spring is arranged in the radial side hole and is used for returning the T-shaped push rod to its original position after pressure relief. 3. The rotary steerable drilling system according to claim 2, characterized in that a limit block is provided on one side of the radial side hole outside the shell. 4. The rotary steerable drilling system according to claim 2, wherein the connecting member comprises: A connecting sleeve, the connecting sleeve is sleeved outside the central shaft, and an outer wall of the connecting sleeve is circumferentially provided with an outwardly protruding connector, and the connector is inserted into the radial side hole; The damping seal is symmetrically arranged on the inner side walls at both ends of the connecting sleeve and is closely attached to the outer wall of the central shaft. 5. The rotary steerable drilling system according to claim 4, wherein the damping seal comprises: A first sealing ring groove, wherein the first sealing groove is arranged on the inner wall of the connecting sleeve; a second sealing ring groove, the second sealing ring groove being disposed on the outer wall of the central shaft and corresponding to the first sealing ring groove; A damping spring, wherein the damping spring is circumferentially arrayed in the first sealing ring groove; a connecting plate, the connecting plate being annular and fixedly connected to the damping spring; and A sealing ring, wherein the sealing ring is fixedly connected to the connecting plate, and the sealing ring is located in the first sealing ring groove and the second sealing ring groove at the same time. 6. The rotary steerable drilling system according to claim 1 is characterized in that a driving member for driving the central shaft to rotate is arranged in the shell, the driving member includes a driving motor, a driving gear is arranged at the output end of the driving motor, a driven gear is sleeved on the central shaft, and the driven gear is meshed with the driving gear. 7. The rotary steerable drilling system according to claim 1 is characterized in that a main shaft is also provided inside the shell, the main shaft is provided with an internal flow channel connected to the upper joint, the internal flow channel is drained into the center hole of the shell, the main shaft is provided with guide vanes, the main shaft is provided with a stator, the main shaft is provided with a rotor outside the main shaft, and the rotor is provided with rotating blades. 8. The rotary steerable drilling system according to claim 7 is characterized in that an integrated control board is also packaged on the main shaft, and the integrated control board integrates a rectifier and voltage stabilization circuit, an attitude measurement sensor, an azimuth gamma sensor, a motor drive board and a main controller. 9. The rotary steerable drilling system according to claim 1, characterized in that a pressure relief hole is also provided on the shell, and a pressure relief valve is provided at the pressure relief hole. 10. The rotary steerable drilling system according to claim 1, characterized in that the housing is detachably connected to the upper joint and the lower joint, and a sealing structure is provided between the housing and the upper joint and the lower joint.