CN115126422A

CN115126422A - Rotary steering drilling tool with self-adaptive supporting structure

Info

Publication number: CN115126422A
Application number: CN202110321614.XA
Authority: CN
Inventors: 不公告发明人
Original assignee: Beijing Quandi Technology Co ltd
Current assignee: Beijing Quandi Technology Co ltd
Priority date: 2021-03-25
Filing date: 2021-03-25
Publication date: 2022-09-30
Also published as: WO2022199666A1

Abstract

The invention relates to a rotary steering drilling tool with a self-adaptive support structure, which changes the direct connection between the tail part of a central shaft and an outer sleeve into the indirect connection through a centering sleeve by adding the centering sleeve and penetrating a flexible shaft in the centering sleeve, increases the moment arm distance in the deformation process of the flexible shaft on the basis of not obviously lengthening a flexible joint, further reduces the working pressure of a bias control mechanism, and improves the use stability and the stratum adaptability of the tool.

Description

Rotary steering drilling tool with self-adaptive supporting structure

Technical Field

The invention relates to the technical field of drilling exploration engineering, in particular to a rotary steering drilling tool with a self-adaptive support structure.

Background

With the development of the petroleum industry, deep wells, ultra-deep wells, extended reach wells and other situations with very high requirements on well drilling well tracks are increasingly appearing in the oil and gas field development process. Aiming at the requirements, the rotary steering drilling tool is generally adopted for directional drilling at present, and particularly the rotary steering drilling tool for changing the direction of a drill bit by adopting the deformation of the acting force of a flexible shaft is smooth and regular in a well hole, so that the rotary steering drilling tool is more favorable for improving the drilling quality and ensuring the drilling safety, and has wider application range and application prospect.

As shown in fig. 1, which is a schematic structural diagram of a drilling tool in the prior art, the drilling tool includes a drill bit 1, a bias control mechanism 4, an outer sleeve 6, a central shaft 8, a first centering bearing 23, a second centering bearing 24, a flexible short joint 25, a fulcrum centralizer 26, an electrical connection line 54, a bias control mechanism driving circuit 55, a control circuit 56, a side push piston accommodating space 61, a side push piston 62, a side push thrust member 63, an energy receiving end 71, an energy output end 72, a plug connector 73, a power supply circuit 81, a modem 82, and an attitude measurement circuit 83. The side thrust piston accommodating space 61, the side thrust piston 62 and the bias control mechanism 4 form a guide short section, and the guide is realized by generating side thrust, and the guide can be dynamic thrust type rotary guide, dynamic mixed type rotary guide, static thrust type rotary guide and static mixed type rotary guide, namely the type of the rotary guide is not limited, and the guide can be static bias rotary guide realized by an outer sleeve 6 or dynamic bias rotary guide. In the prior art, the flexible deformation stress point of the flexible short section is located behind the fulcrum centralizer 26, the flexible short section, namely the flexible deformation section b, is relatively short and far away from a drill bit at the end part of a drilling tool, and when the guide of the section a needs to be changed, a large acting force needs to be used.

In the process of using a rotary steering drilling tool in the prior art, a bias control mechanism 4 is required to apply acting force to a flexible short section by taking a fulcrum centralizer 26 as a fulcrum to generate proper lateral thrust, so that the flexible short section is deformed under the influence of moment of stress, and the drill bit 1 is allowed to deviate from the center line of a well hole in the steering direction; since the drill bit 1 is deflected while the drill bit 1 is kept in rotary excavation. Because the fulcrum centralizer 26 and the drill bit 1 need to keep strong rigidity and proper distance, the fulcrum centralizer 26 is arranged in front of the flexible short section in the prior art. This causes the flexible short section to set up the position too late, so must exert great counter force on the direction short section, just can make the rotatory direction reach the build slope of engineering demand. Namely, the actual acting moment arm distance in the flexible short section deformation process is the distance from the force application point of the bias control mechanism 4 to the fulcrum centralizer. The flexible short section is generally made of metal, and the flexible short section is required to generate enough deformation so that the deflection angle of the guide short section can reach a qualified build slope, so that a very large acting force is often required to be applied to generate enough torque, and the requirement on the thrust of the rotary guide side is further increased due to the limitation of the distance of the force arm; meanwhile, in order to consider the overall stability and safety of the drilling tool, the length of the flexible short section cannot be increased at will, and the required effect can be realized only by outputting stronger acting force by the bias control mechanism 4, so that the tool damages the well wall in the soft stratum drilling process, the fault rate of the bias control mechanism is increased, and the overall reliability of the tool is reduced.

Disclosure of Invention

In order to overcome the defects in the prior art, the invention provides a rotary steering drilling tool with a self-adaptive support structure.

The technical scheme adopted by the invention comprises the following steps:

a rotary steering drilling tool with a self-adaptive support structure is characterized by comprising a steering pup joint, a bias control mechanism driving circuit, an attitude measurement circuit and a self-adaptive support structure;

the guide short section comprises a side pushing device and a drill bit, and the drill bit is arranged at the front part of the guide short section;

the self-adaptive support structure comprises a flexible shaft, a righting sleeve and a fulcrum centralizer; the front part of the centering sleeve is connected with the front part of the flexible shaft, the front end of the flexible shaft is coaxially connected with the connecting part of the centering sleeve, and the flexible shaft generates flexural deformation under the action of outward thrust of the guide short section side pushing device when performing self-rotation motion along the axis of the flexible shaft and deflects along with the front part of the centering sleeve by taking the fulcrum centralizer as a fulcrum;

the lateral pushing device comprises a lateral pushing piston accommodating space and a lateral pushing piston, is arranged in front of the front end face of the centralizing sleeve and is driven by the bias control mechanism to apply acting force perpendicular to the axis of the guide short section to the guide short section; the guide short section is connected to the front part of the flexible shaft and deflects by taking the centralizer as a fulcrum;

an annular deformation space is arranged between the righting sleeve and the flexible shaft, and the front end of the annular deformation space is terminated at the interface of the guide short section and the front part of the righting sleeve.

The centralizing sleeve, the guide short section body and the flexible shaft can be fixedly connected in any mode such as threaded connection, welding, integrated machining and manufacturing, 3D printing and integrated manufacturing and the like; the pivot centralizer and the centralizing sleeve can be fixedly connected in any mode such as threaded connection, welding, integrated machining and manufacturing, 3D printing and integrated manufacturing and the like.

Preferably, an annular deformation space formed between the centering sleeve and the flexible shaft is gradually enlarged from the front to the back from a stress position where the annular deformation space is contacted with the flexible shaft to form a conical annular deformation space, and the stress position where the annular deformation space is contacted with the flexible shaft is at least positioned in front of the foremost end of the fulcrum centering device.

Preferably, the rear part of the guide short section is provided with a righting sleeve mounting position for fixedly connecting the righting sleeve with the rear part of the guide short section; the fixed connection comprises one or more combinations of threaded connection, spline connection and pin connection; the inner diameter of the centralizing sleeve is larger than the outer diameter of any section of the flexible shaft at the rear position of the root part.

Preferably, the axial length e of the annular deformation space is at least 30% of the distance f from the lower end face of the drill bit to the first fulcrum centralizer.

Further preferably, a gap between the inner diameter of the rear portion of the centering sleeve and the outer diameter of the flexible shaft at the corresponding position of the rear portion of the centering sleeve is smaller than or equal to displacement generated by flexural deformation of the flexible shaft in an elastic deformation range, or a diameter difference obtained by subtracting the outer diameter of the flexible shaft at the corresponding position from the inner diameter of the rear portion of the centering sleeve is 1-30 mm.

Preferably, the guide short section is a static offset guide short section, the guide short section comprises an outer sleeve and a central shaft, the drill bit is arranged at the top end of the front part of the central shaft, and the central shaft penetrates through the outer sleeve and the inner part of the outer sleeve and is used for connecting the drill bit and transmitting drilling power;

the offset control mechanism and the side pushing device are both arranged in the cylinder wall of the outer sleeve and are arranged in front of the front end face of the centralizing sleeve along with the outer sleeve, the offset control mechanism is a hydraulic system, the side pushing device comprises a side pushing piston and a side pushing piston accommodating space, and the side pushing part is pushed by the piston to abut against and push the well wall to generate a deflecting effect; the hydraulic system supplies electric power by means of an energy transmission piece, and the energy transmission piece comprises an energy receiving end arranged on the outer sleeve and an energy output end arranged on the righting sleeve and synchronously rotating along with the righting sleeve; the energy receiving end is in contact sliding friction electricity transmission connection with the energy output end, or the energy receiving end is in non-contact coupling induction electric energy transmission with the energy output end.

Preferably, a sealing element for preventing the rock debris in the annular space from flowing into the annular space between the centralizing sleeve and the flexible shaft is arranged between the rear part of the centralizing sleeve and the flexible shaft.

Further preferably, the sealing member is a sealing tube; the sealing tube is in cambered surface contact with the flexible shaft and the righting sleeve, and the sealing tube can deflect with the flexible shaft and the righting sleeve.

Preferably, an ultra-deep hole for realizing the electric connection between the guide short section and other circuits in a rear drill string is formed in the side wall of the flexible shaft.

Preferably, the flexible shaft outer diameter in the self-adaptive support structure is not less than 40% of the drill bit diameter, and is used for transmitting torque and weight on bit and bearing bending moment for the drill bit.

Preferably, the deflection control mechanism comprises a motor, a rotary valve rotor and a rotary valve seat, wherein the motor can drive the rotary valve rotor to rotate relative to the rotary valve seat, and can periodically distribute high-pressure drilling circulating media inside the drilling tool to the side pushing device to push against the well wall to achieve the purpose of guiding.

Preferably, the hinged sleeve is hinged to the front portion of the guide short section through a universal joint, the drill bit is arranged below the hinged sleeve, a pushing piece is arranged on the outer side of the hinged sleeve, and the side-pushing piston transmits the thrust to the well wall through the hinged sleeve and the pushing piece. It should be noted that the pushing member is typically a centralizer.

Preferably, the rear part of the flexible shaft is provided with a second fulcrum centralizer, or the outer sides of other drill strings above the flexible shaft are provided with second fulcrum centralizers, and the distance g from the second fulcrum centralizer to the fulcrum centralizer is less than 300% of the distance f from the lower end face of the drill bit to the first fulcrum centralizer.

Preferably, the bias control mechanism drive circuit and/or the steering control circuit are disposed within or above the flexible shaft.

Preferably, the second attitude measurement circuit is disposed inside or above the flexible shaft, and the second attitude measurement circuit at least includes an accelerometer and/or a magnetometer disposed radially for measuring a gravity toolface angle or inverting the gravity toolface angle by a magnetic toolface angle.

The invention has the beneficial effects that:

by adopting the rotary steering drilling tool with the self-adaptive support structure, the distance between the centralizer and the drill bit is extended by adding the self-adaptive support structure consisting of the centralizer sleeve, the fulcrum centralizer and the flexible shaft, and the flexible deformation stress point of the flexible shaft is moved backwards to the front part of the centralizer from the original rear position of the centralizer by a method of penetrating the flexible shaft into the centralizer sleeve, so that the flexibility of the rotary steering system is increased on the premise of not obviously prolonging the whole length of the drilling tool and not reducing the diameter and the length of the flexible short section, and the deformable section of the rotary steering system is extended downwards, thereby reducing the thrust required in the guiding process of the drilling tool or increasing the deflecting force of the rotary steering system under the same thrust condition, reducing the use and maintenance cost of the drilling tool and improving the whole reliability of the drilling tool; the distance from the centralizer to the well bottom can be set according to actual needs, a flexible configuration mode is achieved, the design of various drilling tools can be adapted, and various different drilling tool offset control mechanisms can be compatible.

The method through adding the sleeve of rightting and wearing to establish the flexbile shaft inside rightting the sleeve will originally set up the fulcrum centralizer that sets up in flexbile joint front portion in the sleeve outside of rightting, the front portion of rightting the sleeve and the rear portion coaxial coupling of direction nipple joint, the rear portion of direction festival passes through the flexbile shaft is connected with the rear drilling string, makes between fulcrum centralizer and the direction nipple joint be direct connection become through the indirect connection of rightting the sleeve, for embodying better effect, can keep the flexbile nipple joint among the prior art, promptly the flexbile shaft rear is through the further connection rear drilling string of flexbile nipple joint. According to the invention, the flexible shaft penetrates through the inner part of the centering sleeve and forms a deformable short section with the centering sleeve to form an annular deformation space. The moment arm distance in the deformation process of the flexible shaft is increased on the basis of not obviously lengthening the flexible joint, so that the working pressure of a bias control mechanism is reduced, and the use stability and the stratum adaptability of the tool are improved.

For the preferred scheme, the bias control mechanism driving circuit is arranged inside or above the flexible shaft, so that the length of the guide short section can be reduced to the greatest extent, the effect of the flexible section can be better exerted, the obstruction of a drill string behind the guide short section to the guide short section is reduced to the greatest extent, and the side pushing device can push the guide short section to deflect with smaller force. In addition, the offset control mechanism driving circuit is arranged behind the flexible shaft, so that damage of vibration to the circuit can be sufficiently reduced.

Drawings

FIG. 1 is a schematic diagram of a prior art well tool configuration;

FIG. 2 is a schematic structural view of embodiment 1 of the present invention;

FIG. 3 is a schematic structural view of embodiment 2 of the present invention;

FIG. 4 is a partial structural view of a sealing tube in accordance with embodiment 2 of the present invention;

FIG. 5 is a schematic structural diagram of embodiment 3 of the present invention;

fig. 6 is a schematic diagram of an improved structure in embodiment 3 of the present invention.

Description of the figure numbering:

the device comprises a drill bit 1, a flexible shaft 2, a bias control mechanism 4, a motor 41, a rotary valve rotor 42, a rotary valve seat 43, a rotary transformer 44, a centering sleeve 5, an outer sleeve 6, a sealing pipe 7, a central shaft 8, a first centering bearing 23, a second centering bearing 24, a flexible short joint 25, a fulcrum centering device 26, a centering sleeve 29, an electric connecting line 54, a bias control mechanism 55 driving circuit 56, a control circuit 61, a side push piston accommodating space 61, a side push piston 62, a side push pushing part 63, an energy receiving end 71, an energy output end 72, an energy plug connector 73, a power supply circuit 81, a modem 82, an attitude measurement circuit 83 and a second attitude measurement circuit 84.

Detailed Description

For a clearer understanding of the contents of the present invention, reference will be made to the accompanying drawings and examples.

Example 1

Fig. 2 is a schematic structural diagram of a drilling tool embodiment 1 of the present invention, which includes, in addition to part of the structure shown in fig. 1, a flexible shaft 2 and a centering sleeve 29; the front part of the righting sleeve 29 is fixedly connected with the front part of the flexible shaft 2, the flexible shaft 2 does self-rotation motion along the axis and bends under the biasing action of the guide short section, so that the front part of the flexible shaft 2 deflects by taking the fulcrum centralizer 26 as a fulcrum, and an ultra-deep hole is formed in the side wall of the flexible shaft 2 and used for realizing the electric connection of the rotary guide short section and other circuits in a rear drill string; the bias control mechanism 4 is arranged in front of the front end face of the centralizing sleeve 29 and applies acting force perpendicular to the axis of the guide short section; the guide sub deflects about the fulcrum centralizer 26. A drill bit 1 protruding out of the outer sleeve is arranged at the top end of the front part of the guide short section; an annular deformation space is arranged between the righting sleeve 29 and the flexible shaft, and the front end of the annular deformation space is connected with the front part of the righting sleeve 29 through the guide short section. In the present invention, the flexible shaft 2 is inserted into the sleeve and deformed in the sleeve, so that the flexible deformation section b is greatly close to the drill bit 1, and therefore, the build rate can be increased under the same thrust condition or the necessary thrust can be minimized under the same condition of the need for the build rate.

Example 2

Referring to fig. 3 and 4, which are schematic structural diagrams of an embodiment 2 of the drilling tool of the invention, in addition to embodiment 1, a sealing pipe 7 is added between the rear part of the centering sleeve 29 and the flexible shaft 2, and the sealing pipe 7 is used for preventing rock debris in the annular space from flowing into the annular space between the centering sleeve 29 and the flexible shaft 2. Cambered surface contact is adopted among the sealing tube 7, the flexible shaft 2 and the centering sleeve 29, and deflection is allowed to occur among the sealing tube 7, the flexible shaft 2 and the centering sleeve 29. It should be noted that the sealing tube 7 may also be replaced by a sealing bladder or other sealing member, and the sealing member mainly seals off dirt such as rock debris, and does not require fluid sealing. In the specific implementation process, the annular deformation space between the centering sleeve 29 and the flexible shaft 2 can be filled with oil and can also be used for letting drilling fluid flow in. The purpose of the seal is only to prevent debris-like dirt from filling the annular deformation space, resulting in a resistance to flexible joint deformation.

The cross section area of the annular deformation space formed between the centering sleeve 29 and the flexible shaft 2 is gradually enlarged from the front to the back from the stress position where the annular deformation space is in contact with the flexible shaft 2 to form a conical annular deformation space, and the stress position where the annular deformation space is in contact with the flexible shaft is at least positioned in front of the foremost end of the fulcrum centralizer 26. It should be noted that, because the root of the flexible shaft 2 is subjected to the greatest stress during the rotation guide whip, the tapered annular deformation space exists only near the root of the flexible shaft 2, i.e., at the position c shown in fig. 3, and the main function is to prevent the stress concentration at the root of the flexible shaft 2.

And a righting sleeve mounting position 5 is arranged at the rear part of the guide short section and is used for fixedly connecting the righting sleeve with the rear part of the guide short section. The fixed connection mode can be one or more of threaded connection, spline connection and pin connection. It should be noted that the inner diameter of the centering sleeve needs to be larger than the outer diameter of any section of the flexible shaft 2 at a later position of the root, so as to ensure that the centering sleeve 29 can be smoothly sleeved outside the flexible shaft 2. It should be noted that, in the present invention, the guide nipple refers to a section in which the biasing mechanism is specifically installed, and the guide nipple is connected to the front of the flexible shaft 2. Therefore, in the invention, the front of the flexible shaft and the rear of the guide short piece are the same concept.

The diameter difference obtained by subtracting the inner diameter of the rear part of the righting sleeve 29 from the outer diameter of the flexible shaft 2 at the corresponding position is 1-30 mm.

The clearance between the inner diameter of the rear end of the centering sleeve 29 and the outer diameter of the flexible shaft 2 at the position corresponding to the rear end of the centering sleeve 29 is less than or equal to the displacement generated by the flexible shaft 2 in the elastic deformation range. It should be noted that, during normal deflecting operation of the rotary steering, the displacement caused by the flexible deformation of the flexible shaft 2 is smaller than the annular space gap distance at the corresponding position between the centering sleeve 29 and the flexible shaft 2, so as to prevent the flexible shaft 2 from breaking under vibration of the tool or other extreme conditions. The annular space gap is not larger than the displacement resulting from yielding of the flexible shaft 2.

The well drilling tool is static bias rotary guide, the static bias rotary guide comprises an outer sleeve 6 and a central shaft 8, the bias control mechanism and a pushing element are arranged on the wall of the outer sleeve 6, the bias control mechanism is a hydraulic system, and a piston pushes the pushing element to push against the well wall to generate a deflecting effect. The hydraulic system is powered by means of an energy transmission member comprising an energy receiving end 71 arranged on the outer sleeve and an energy output end 72 arranged on the righting sleeve 29 and rotating synchronously with the righting sleeve; the energy receiving end 71 and the energy output end 72 are in contact sliding friction electric transmission connection, or the energy receiving end 71 and the energy output end 72 adopt non-contact coupling induction electric energy transmission.

Example 3

As shown in fig. 5 and 6, the technical solution adopted by the present invention includes: a rotary steering drilling tool with a self-adaptive support structure is characterized by comprising a steering pup joint, a bias control mechanism driving circuit, an attitude measurement circuit and a self-adaptive support structure;

the guide short section comprises a side pushing device and a drill bit 1, and the drill bit is arranged at the front part of the guide short section;

the adaptive support structure comprises a flexible shaft 2, a centering sleeve 6 and a fulcrum centralizer 26; the front part of the centering sleeve is connected with the front part of the flexible shaft, the front end of the flexible shaft is coaxially connected with the connecting part of the centering sleeve, and the flexible shaft generates flexural deformation under the action of outward thrust of the guide short section side pushing device when performing self-rotation motion along the axis of the flexible shaft and deflects along with the front part of the centering sleeve by taking the fulcrum centralizer as a fulcrum;

the side pushing device comprises a side pushing piston accommodating space 61 and a side pushing piston 62, the side pushing device is arranged in front of the front end face of the centralizing sleeve, and the side pushing device is driven by the bias control mechanism to apply acting force perpendicular to the axis of the guide short section to the guide short section; the guide short section is connected to the front part of the flexible shaft, and the guide short section deflects by taking the fulcrum centralizer 26 as a fulcrum; the side thrust piston 62 may push against the borehole wall directly or through other components to transmit the thrust force to the borehole wall.

An annular deformation space is arranged between the righting sleeve 6 and the flexible shaft, and the front end of the annular deformation space is terminated at the interface of the guide short section and the front part of the righting sleeve.

An annular deformation space formed between the righting sleeve and the flexible shaft is gradually enlarged from the front to the back from a stress position where the annular deformation space is contacted with the flexible shaft to form a conical annular deformation space, and the stress position where the annular deformation space is contacted with the flexible shaft is at least positioned in front of the foremost end of the fulcrum righting device.

An ultra-deep hole for realizing the electric connection between the guide short section and other circuits in a rear drill string is arranged in the side wall of the flexible shaft, and an electric connection line 54 is arranged in the hole in a penetrating manner and used for realizing the electric power and/or communication connection between the motor 41 and the bias control mechanism driving circuit 55, so that the bias control mechanism driving circuit 55 can control the motor to rotate. The deflection control mechanism comprises a motor 41, a rotary transformer 44, a rotary valve rotor 42 and a rotary valve seat 43, wherein the motor can drive the rotary valve rotor 42 to rotate relative to the rotary valve seat 43, and can periodically distribute high-pressure drilling circulating media inside the drilling tool to a side pushing device to push against a well wall to achieve the purpose of guiding. The rotary valve seat 43 is fixedly connected with the guide short section body, the rotary valve seat 43 is provided with a plurality of valve positions which are respectively in one-to-one correspondence with the side pushing piston accommodating spaces 61, the valve positions are communicated with the corresponding side pushing piston accommodating spaces 61 through flow channels, the motor 41 is fixedly connected with the guide short section body, the output end of a driving shaft of the motor is coupled with the rotary valve rotor 42, the rotary valve rotor 42 can be driven to rotate relative to the rotary valve seat 43, the side pushing piston accommodating spaces 61 can be periodically communicated with water holes in a drilling tool, high-pressure drilling fluid is obtained, and the driving side pushing pistons 62 can periodically generate thrust.

The control circuit 56 stores a preset guiding direction, and can control the motor to rotate along the direction opposite to the drilling tool through the bias control mechanism driving circuit 55, and control the driving side pushing piston 62 to push against the well wall in the direction opposite to the guiding direction. The control circuit 56 and the bias control mechanism driving circuit 55 can be implemented by using a single PCB or by dividing two PCBs. The preset mode of presetting the guiding direction can be presetting before the tool is put into the well or presetting through a signal under the pressure change or flow change of mud in the drilling process; the drilling fluid from the drill string bore will generate a pressure drop when passing through the nozzle or the throttling structure, the pressure drop is the working pressure difference of the side thrust piston 62, the specific process and principle of generating the pressure difference are common knowledge in the art, and are not described herein. The periodic communication means that the communication between the through flow passage and the driving hydraulic cylinder is periodically changed along with the rotation of the drilling tool so as to ensure that the side pushing piston 62 in a specific sector obtains hydraulic pressure. The mutual coupling refers to a connection mode which can ensure that the driving motor rotor and the rotary valve rotor synchronously rotate, and includes but is not limited to plugging.

The bias control mechanism driving circuit and the guide control circuit are both arranged in a sealed pressure-bearing bin, and the sealed pressure-bearing bin is arranged in the drill collar above the flexible shaft.

The second attitude measurement circuit is arranged in or above the flexible shaft, and at least comprises an accelerometer and a magnetometer which are arranged along the radial direction and used for measuring the face angle of the gravity tool or inverting the face angle of the gravity tool through the face angle of the magnetic tool.

And a second fulcrum centralizer 27 is arranged at the rear part of the flexible shaft, or a second fulcrum centralizer 27 is arranged on the outer side of other drill strings above the flexible shaft.

The difference between fig. 6 and fig. 5 is that the embodiment shown in fig. 6 is a lift of the embodiment shown in fig. 5, and further includes an articulated sleeve 3 and a universal joint 32, the articulated sleeve is hinged to the front portion of the guide sub through the universal joint 32, the drill bit 1 is arranged coaxially with the articulated sleeve 3, the drill bit 1 is arranged at the lower end of the articulated sleeve, the universal joint 32 is responsible for transmitting the weight and the torque, a pushing member 63 is arranged outside the articulated sleeve, the pushing member is a centralizer integrally manufactured with the articulated sleeve, and the side-push piston 62 transmits the thrust to the well wall through the articulated sleeve 3 and the pushing member 63.

The above embodiments can correspond to the cylindrical annular deformation space or the conical annular deformation space in the specific implementation process. When the scheme of the conical annular deformation space is adopted, the contact stress position between the annular deformation space and the flexible shaft is preferably curved surface contact rather than point contact, and the specific curved surface radian of the curved surface contact is designed to be matched with the bending radian generated when the flexible shaft is subjected to flexible deformation so as to increase the stress area as much as possible and reduce overlarge local pressure when the flexible shaft is subjected to stress deformation.

The patent does not limit the type of the rotary guide, and the static offset rotary guide of the guide realized by the outer sleeve or the dynamic offset rotary guide without the outer sleeve are both in the protection scope of the patent;

when the drilling tool is used for drilling operation, the torque and the bending moment required in the working process are transmitted by the flexible shaft, and the required bit pressure is transmitted by the flexible shaft and/or the centering sleeve and the outer sleeve with the thrust structure through the self-rotating torsion connecting mechanism. It should be noted that the technical innovation claimed by the present invention lies in the structural formation of the annular deformation space in the drilling tool and the effect thereof, and the transmission mode of the torque, the bending moment and the weight on bit in the working state of the drilling tool and the corresponding structural change of the drilling tool do not affect the technical scheme claimed by the present invention, and the protection scope of the present invention should not be limited thereby.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A rotary steering drilling tool with a self-adaptive support structure is characterized by comprising a steering pup joint, a bias control mechanism driving circuit, an attitude measurement circuit and a self-adaptive support structure;

the side pushing device comprises a side pushing piston accommodating space and a side pushing piston, the side pushing device is arranged in front of the front end face of the centralizing sleeve, and the bias control mechanism applies acting force perpendicular to the axis of the guide short section to the guide short section; the guide short section is connected to the front part of the flexible shaft and deflects by taking the centralizer as a fulcrum;

2. The well tool of claim 1, wherein the annular deformation space defined between the centering sleeve and the flexible shaft gradually expands from a forward to a rearward direction as the annular deformation space contacts the flexible shaft, to form a conical annular deformation space, and wherein the annular deformation space contacts the flexible shaft at a force location at least forward of the forward-most end of the fulcrum centralizer.

3. The drilling tool as claimed in claim 1 or 2, wherein the rear portion of the guide sub is provided with a righting sleeve mounting location for fixedly connecting the righting sleeve with the rear portion of the guide sub; the fixed connection comprises one or more combinations of threaded connection, spline connection and pin connection; the inner diameter of the centralizing sleeve is larger than the outer diameter of any section of the flexible shaft at the rear position of the root part.

4. A drilling tool as claimed in claim 1 or 2, wherein the annular deformation space has an axial length of at least 30% of the distance from the lower face of the drill bit to the first point centralizer.

5. The well tool of claim 1 or 4, wherein the clearance between the inner diameter of the rear portion of the centering sleeve and the outer diameter of the flexible shaft at the corresponding position of the rear portion of the centering sleeve is less than or equal to the displacement of the flexible shaft due to the flexural deformation in the elastic deformation range, or the difference between the inner diameter of the rear portion of the centering sleeve and the outer diameter of the flexible shaft at the corresponding position is 1 to 30 mm.

6. A drilling tool as claimed in claim 1 or 2, wherein the guide sub is a static offset guide sub comprising an outer sleeve and a central shaft, the drill bit being disposed at the top of the front of the central shaft, the central shaft passing through the outer sleeve and the inner sleeve for connection of the drill bit and transmission of drilling power;

7. A drilling tool as claimed in claim 1 or 2, wherein a seal is provided between the rear of the centralising sleeve and the flexible shaft to prevent debris in the annulus from flowing into the annulus between the centralising sleeve and the flexible shaft.

8. The well tool of claim 7, wherein the seal is a seal tube; the sealing tube is in cambered surface contact with the flexible shaft and the righting sleeve, and the sealing tube can deflect with the flexible shaft and the righting sleeve.

9. A well tool as claimed in claim 1 or claim 2, wherein the flexible shaft side wall is provided with an ultra-deep bore therein for enabling electrical connection of the guide sub to other circuitry in a subsequent drill string.

10. A drilling tool as claimed in claim 1 or 2, wherein the flexible shaft outer diameter in the adaptive support structure is not less than 40% of the drill bit diameter for transmitting torque and weight on bit and for taking up bending moments.

11. The well tool of claim 1, wherein the deflection control mechanism comprises a motor, a rotary valve rotor, and a rotary valve seat, wherein the motor is capable of driving the rotary valve rotor to rotate relative to the rotary valve seat, and is capable of periodically distributing high-pressure drilling circulating medium inside the well tool to the lateral thrust device to push against the well wall for steering purposes.

12. The drilling tool as claimed in claim 1, wherein the articulated sleeve is hinged to the front part of the guide short section through a universal joint, the drill bit is arranged at the front part of the articulated sleeve, the outer side of the articulated sleeve is provided with a pushing piece, and the side-pushing piston transmits the pushing force to the well wall through the articulated sleeve and the pushing piece.

13. The well tool of claim 1, wherein the rear portion of the flexible shaft is provided with a second fulcrum centralizer 27, or wherein a second fulcrum centralizer 27 is provided on the outside of the drill string above the flexible shaft.

14. A well tool as claimed in any of claims 1, 11 or 12, wherein the bias control mechanism drive circuit and/or the steering control circuit is disposed within or above the flexible shaft; when the bias control mechanism driving circuit is arranged above the flexible shaft, the bias control mechanism driving circuit is electrically connected with the motor through an electric connecting wire, and the electric connecting wire is arranged inside the flexible shaft or in the pipe wall of the flexible shaft.

15. A drilling tool as claimed in any one of claims 1, 11 or 12, wherein the first attitude measurement circuit is provided in the guide sub and the second attitude measurement circuit is provided within or above the flexible shaft, the second attitude measurement circuit comprising at least a radially disposed accelerometer and/or magnetometer for measuring or inverting a gravity toolface angle via a magnetic toolface angle, the control circuit being electrically connected to the first attitude measurement circuit via an electrical connection.