Static bias rotary steering drilling tool with sandwich cylinder structureTechnical Field
The invention relates to the technical field of drilling exploration engineering, in particular to a static bias rotary steering drilling tool with a sandwich cylinder structure.
Background
With the development of petroleum industry, well types with very high requirements on drilling well tracks, such as deep wells, ultra-deep wells, large-displacement wells and the like, are increasingly generated in the development process of oil and gas fields. In order to meet the requirement, the rotary steerable drilling tool is generally used for directional drilling at present, and particularly, the static bias rotary steerable drilling tool with better reliability is adopted, so that the well bore is smooth and regular, the drilling quality is improved, the drilling safety is ensured, and the rotary steerable drilling tool has wider application range and application prospect.
In the prior art, it is often difficult to normally run out or re-run in a high curvature wellbore without rotating the sleeve while drilling with a rotary steerable tool because the sleeve is too thick and too long. Meanwhile, the overlong non-rotating sleeve also brings difficulty to setting positions of the centralizers and carrying rock fragments.
Accordingly, one skilled in the art would provide a sandwich static biased rotary steerable drilling tool that addresses the problems set forth in the background above.
Disclosure of Invention
In order to achieve the above purpose, the present invention provides the following technical solutions: the static bias rotary steering drilling tool with the sandwich cylinder structure comprises a non-rotary sleeve, a bias control mechanism, a driving shaft assembly, a central shaft and a drill bit, wherein the rear part of the non-rotary sleeve is provided with a rear centralizing section of the non-rotary sleeve, and the front part of the non-rotary sleeve is connected with the front part of the central shaft through a structure with centralizing function;
it should be noted that the non-rotating concept of the non-rotating sleeve is relative to a drill string rotating at high speed and is not absolutely stationary. The non-rotating sleeve may also rotate slowly or intermittently relatively much, but the relatively high speed rotating drill string is close to non-rotating, and is therefore referred to as a non-rotating sleeve.
The drive shaft assembly at least comprises a centralizing sleeve and a central shaft, a rear centralizing section accommodating space is arranged in the centralizing sleeve, the axial length of the rear centralizing section accommodating space is matched with that of the rear centralizing section of the non-rotating sleeve, the inner diameter of the centralizing sleeve is mutually matched with the outer diameter of the rear centralizing section of the non-rotating sleeve, the rear centralizing section of the non-rotating sleeve can be accommodated in the centralizing sleeve, and the rear centralizing section of the non-rotating sleeve can be inserted into the centralizing sleeve;
the centralizing sleeve is connected with the rear centralizing Duan Tongzhou of the non-rotating sleeve at least through a centralizing bearing, so that the axis of the centralizing sleeve is always coincident with the axis of the non-rotating sleeve, and the centralizing sleeve is also connected with the rear drilling column so as to be capable of performing self-rotation motion along the axis of the rear drilling column under the driving of the rear drilling column;
The offset control mechanism is arranged in front of the rear centralizing section of the non-rotating sleeve and is arranged on the wall of the non-rotating sleeve and used for driving the rotary steering drilling tool to change the track direction of the borehole, and the offset control mechanism is any one or combination of a pushing type offset control mechanism and a pointing type offset control mechanism;
It should be noted that the static bias rotation guide of a sandwich cylinder structure in the present invention is not limited to any kind of bias control mechanism, for example, in a static bias hybrid rotation guide of a sandwich cylinder structure, a push-type bias control mechanism and a directional bias control mechanism exist at the same time.
The front end part of the central shaft is fixedly provided with a drill bit protruding out of the non-rotating sleeve, and the rear end of the central shaft is fixedly connected with the centralizing sleeve.
Further, preferably, the centralizing sleeve further comprises a central shaft mounting position, the centralizing sleeve is fixedly connected with the central shaft through the central shaft mounting position, the axis of the rear end of the central shaft is always coincident with that of the centralizing sleeve, the central shaft and the centralizing sleeve can synchronously and automatically rotate under the driving of a rear drill string, torque is transmitted to the drill bit, and the central shaft and the centralizing sleeve are connected in any one or combination of a bolt connection, a spline connection, a pin connection, an insertion connection and a threaded connection.
Further, preferably, the front part of the non-rotating sleeve is connected with the front part of the central shaft through a third centralizing bearing;
a front thrust bearing and a rear thrust bearing are also included for preventing the non-rotating sleeve from falling off the central shaft assembly.
The non-rotating sleeve is sleeved outside the central shaft, and the central shaft is connected with the rear drill post, so that the non-rotating outer cylinder can be prevented from falling off from the central shaft only by connecting the non-rotating sleeve with the central shaft or other parts on the driving shaft assembly through a bearing with a thrust function during drilling.
Further, preferably, the front part of the non-rotating sleeve is connected with the front part of the central shaft through a focusing centralizing bearing, and the central shaft can perform self-rotation along the axis of the central shaft and perform torsion pendulum motion relative to the non-rotating sleeve by taking the focusing centralizing bearing as the center;
It should be noted that the focusing centralizing bearing can firstly realize the function of the centralizing bearing, and allow the central shaft to rotate along the self axis in the non-rotating sleeve for driving the drill bit to rotate. The torsional pendulum motion is due to the fact that the inner (28) and outer (29) rings of the focus bearing are in spherical contact, thus permitting the front portion of the center shaft to oscillate in a cross-section along the tool axis, such as in a similar cross-section as shown in fig. 1, centered on the focus bearing.
The static bias rotary guide of the sandwich cylinder structure at least comprises a directional bias control mechanism, wherein the bias control mechanism is used for applying a force perpendicular to the axis of the central shaft to the central shaft so as to deviate the front axis of the central shaft from the axis of the non-rotary sleeve by a certain angle, the deviation angle is within 3 degrees, the axis of the drill bit deviates from the axis of the non-rotary sleeve, and the drill bit drills along the deviation direction of the drill bit, so that the guide purpose is achieved;
The centralizing sleeve is connected with the rear centralizing Duan Tongzhou of the non-rotating sleeve through at least two sets of centralizing bearings, namely a first centralizing bearing and a second centralizing bearing, or the centralizing sleeve is connected with the rear centralizing Duan Tongzhou of the non-rotating sleeve through at least one set of centralizing bearings with the length of the centralizing surface exceeding more than 1.5 times of the diameter of the rear centralizing section of the non-rotating sleeve, and is used for keeping the coaxial relationship between the centralizing sleeve and the non-rotating sleeve.
Further, preferably, an external bias pushing piece is arranged in the wall of the non-rotating sleeve and used for pushing against the well wall under the action of hydraulic pressure, so that the non-rotating sleeve is kept generally stationary relatively.
Further preferably, the device further comprises an energy transfer device for transferring electric energy from a power supply circuit provided in the centralizing sleeve or in the drill string behind it to the individual electrical consumers in the non-rotating sleeve; the energy transmission device comprises an energy emission device and an energy receiving device; the energy transmitting device is fixedly connected with the centralizing sleeve, and the energy receiving device is fixedly connected with the non-rotating sleeve; the energy receiving device is inserted in the energy transmitting device, the energy transmitting device and the energy receiving device transmit electric energy in a brush contact mode or in a non-contact coupling induction mode, and the energy transmitting device is arranged behind the centralizing bearing.
Further, preferably, the focusing centralizing bearing comprises a spherical bearing, a universal joint with a centralizing bearing sleeved inside, or a universal joint with a centralizing bearing sleeved outside.
Further, preferably, the offset control mechanism at least includes a guiding offset control mechanism, the offset control mechanism is disposed between the focusing centralizing bearing and the first centralizing bearing and is sleeved on the central shaft, the offset control mechanism is connected with the central shaft through a follow-up centralizing bearing, and can apply a force perpendicular to the axis of the central shaft between the focusing centralizing bearing and the first centralizing bearing while not affecting the rotation of the central shaft along the axis of the central shaft.
In the hybrid or directional rotary guide of the sandwich cylinder structure, the offset control mechanism is disposed on the cylinder wall and does not rotate substantially. Therefore, a follow-up centralizing bearing is required to be arranged between the offset control mechanism and the central shaft, so that the autorotation of the central shaft is not influenced.
Further, preferably, a centrally-mounted centering bearing is disposed between the first centering bearing and the third centering bearing, for ensuring stability of the drive shaft, without buckling deformation in the non-rotating sleeve or damage due to vibration.
In the case of the push-type static bias rotary guide of the sandwich cylinder structure, the length of the center shaft is increased to reduce the stability of the center shaft, although the exposed length of the non-rotary sleeve is reduced by the additional centralizing sleeve in the device. Therefore, the device gives full play to the effect, and the centrally-arranged centralizing bearing is arranged between the first centralizing bearing and the third centralizing bearing, so that the driving shaft can be effectively protected, and the stability of the driving shaft is not reduced and raised compared with the prior art.
Further, as the outer diameter of the centralizer is larger than that of the non-rotating sleeve, the centralizer is arranged on the outer side of the centralizing sleeve and can form a supporting effect with the drill bit in front of the non-rotating sleeve, so that the situation that the non-rotating sleeve and the well wall are scratched and stuck is better avoided.
Further, preferably, the bias control mechanism is a hydraulic bias control mechanism, the hydraulic bias control mechanism comprises 3-4 external bias pushing pieces arranged along the circumference of the non-rotating sleeve, and the sum of forces applied by the 3-4 external bias pushing pieces to the well wall is larger than 20000N during the rotation guiding operation, so that the non-rotating sleeve is provided with enough sliding friction force for overcoming the centralizing sleeve and the non-rotating sleeve to keep the non-rotating sleeve relatively static to the rear drill string; the centralizing sleeve is connected with the rear centralizing Duan Tongzhou of the non-rotating sleeve through at least two centralizing bearings with the distance being more than 2.5 times of the diameter of the rear centralizing section, or the centralizing sleeve is connected with the rear centralizing Duan Tongzhou of the non-rotating sleeve through at least one centralizing bearing with the length being more than 2.5 times of the diameter of the rear centralizing section of the non-rotating sleeve, and is used for keeping the coaxial relation between the centralizing sleeve and the non-rotating sleeve, and the friction force provided by the pushing piece is ensured to be larger than that of the bearing.
It is noted that, according to the conventional principle of push-type rotary steerable technique, when the rotary steerable directional drilling is performed, the borehole has a certain curvature, and when the rotary steerable tool is in the borehole having a certain curvature, a bending moment exists in the rotary steerable and the drill string behind the rotary steerable tool. In static pushing and rotating guiding, the bending moment needs to be transmitted to the rear drill column through a centralizing and thrust compound bearing which is arranged at the upper end and the lower end of the non-rotating sleeve and the upper end and the lower end of the central shaft. In the invention, the bending moment is transmitted through the non-rotating sleeve and the centralizing sleeve instead of through the bearing with the upper end and the lower end connected with the non-rotating sleeve, so that the total centralizing length between the centralizing sleeve and the non-rotating sleeve needs to meet the set requirement of the device, and the lever arm required by transmitting the bending moment can be lengthened, thus obtaining good effect.
Compared with the prior art, the invention has the beneficial effects that:
The push-type static bias rotary steering drilling tool with the sandwich cylinder structure has the advantages that the push-type static bias rotary steering drilling tool with the sandwich cylinder structure is characterized in that the support sleeve is sleeved outside the non-rotary sleeve to form the sandwich cylinder structure, and the support sleeve and the non-rotary sleeve are used for transmitting bending moment through the bearing, so that the conventional push-type static bias rotary steering is improved in the manner that the support sleeve and the non-rotary sleeve are provided with the support and thrust composite bearings at the upper end and the lower end of the non-rotary sleeve and the upper end and the lower end of the central shaft to transmit bending moment, so that the stress relation is improved, the problem that the thrust bearing of the original system bears the bending moment is solved, and the friction force from the bearing received by the non-rotary sleeve is not influenced by the fluctuation of the drilling pressure. And the centralizing sleeve is sleeved on the outer side of the non-rotating sleeve, so that the exposure length of the non-rotating sleeve is reduced. For example, in existing push-against rotary guides, the coupler and rear centralizing bearing are inserted into a non-rotating sleeve; in the invention, the coupler and the rear centralizing bearing are inserted into the centralizing sleeve, namely, the exposed parts outside the corresponding sections of the coupler and the rear centralizing bearing are centralizing sleeves. The length of the non-rotating sleeve exposed in the borehole annulus is reduced, reducing the risk of the static biased rotary steerable stuck drill.
Rotational steering for hybrid or directional static biasing. The advantages of the hybrid or directional static biased rotary steerable drilling tool of the sandwich cartridge configuration of the present invention are, for example, that disclosed in "a rotary steerable control method" described in US 6244361B 1; the disclosure of "a directional drilling device" is described in application number CN 201811504768.7. The righting connection between the non-rotating sleeve of the directional static-biased rotary guide or the hybrid static-biased rotary guide and the rear drill string is achieved through the central shaft, i.e. the non-rotating sleeve and the rear of the central shaft are in righting relation through a righting bearing, and the rear of the central shaft is generally about a section 1/3 behind the central shaft. And then the rear part of the central shaft is fixedly connected with the rear drill column, and the central shaft is inserted into the non-rotating sleeve, so that the connecting mode greatly increases the exposed area of the non-rotating sleeve, and the risk of the rotary guide drill sticking is increased. The invention adopts the method that the centering sleeve outside the non-rotating sleeve forms a sandwich structure with the rear part of the non-rotating sleeve and the central shaft, and the coaxial centering function between the non-rotating sleeve and the rear drill string is borne by the centering sleeve on the premise of not influencing and blocking the flexible deformation of the central shaft even if the non-rotating sleeve does not need to realize the coaxial centering relationship with the rear drill string through the central shaft. Therefore, the rear centralizing section of the non-rotating sleeve is inserted into the centralizing sleeve, the coaxial connection between the non-rotating sleeve and the centralizing bearing is realized by directly utilizing the bearing between the non-rotating sleeve and the centralizing sleeve, the centralizing sleeve is used as an intermediate body, the coaxial connection between the non-rotating sleeve and the centralizing sleeve rear drill column is realized, the length of the non-rotating sleeve exposed outside is shortened, and the possibility that a drilling tool faces blocking in the process of tripping or tripping in a high-curvature borehole is reduced, and the use and maintenance cost and the fault rate of an offset control mechanism of the drilling tool are reduced.
The reason why the non-rotating sleeve and the rear drill post are required to be coaxial in the beneficial effects is that the non-rotating sleeve type guide actuating mechanism is not required to rotate, so that the lateral cutting or deflection of the drill bit is controlled, and a centralizer is required to be used as a fulcrum. It is therefore necessary to ensure that the sleeve is not rotated coaxially with the trailing drill string. In addition, to ensure stability of the drill string, to prevent buckling of the drill string, etc., it is the basis for good functioning of the rotational guidance that the non-rotating sleeve remains coaxial with the rear drill string. This is also demonstrated by the extensive practice of drilling engineering.
Drawings
FIG. 1 is a schematic cross-sectional view of a hybrid static bias rotary steerable drilling tool of a sandwich construction;
FIG. 2 is a schematic partial cross-sectional view of a hybrid static bias rotary steerable drilling tool of a sandwich configuration;
FIG. 3 is a schematic cross-sectional view of a push-against static bias rotary steerable drilling tool of a sandwich construction;
FIG. 4 is a schematic partial cross-sectional view of a push-against static bias rotary steerable drilling tool of a sandwich construction;
FIG. 5 is a schematic view of a prior art connection between a central shaft and a non-rotating sleeve; the part B is a schematic diagram of a connecting mode of a non-rotating sleeve, a central shaft and a centralizing sleeve after the centralizing sleeve is added in the utility model; wherein d is the outer diameter of the centralizing section after the sleeve is not rotated;
In the figure: 1. a drill bit; 2. a focusing centralizing bearing; 3. centralizing the bearing; 501. centralizing the bearing installation position; 502. A central shaft installation position; 6. the sleeve is not rotated; 10. a biasing barrel; 11. an inner offset piston; 12. a hydraulic line; 13. an electrical connection line; 21. a third centralizing bearing; 21-2, a lower thrust bearing; 22. a follow-up righting bearing; 23. a first centralizing bearing; 23-2 upper thrust bearing; 24. a second centralizing bearing; 25. a central shaft; 26. centralizing the sleeve; 27. a centering bearing is arranged in the middle; 28. focusing and righting the bearing inner ring; 29. a focusing centralizing bearing outer ring; 53. A power fluid pipeline; 54. an electrical connection line; 55. a motor driving circuit; 56. a control module; 60. a hydraulic system; 61. an externally biased piston cylinder; 62. an externally biased piston; 63. an outer biasing abutment; 64. a motor; 65. a hydraulic pump; 67. a pressure sensor; 71. an energy receiving end; 72. an energy output; 75. a centralizer; 81. a power supply circuit; 82. a modem.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
First embodiment: referring to fig. 1,2 and 5, a sandwich static bias hybrid or directional rotary steerable drilling tool, which is one of the sandwich static bias rotary steerable of the present invention, comprises a non-rotatable sleeve 6, a bias control mechanism, a drive shaft assembly, a central shaft 25 and a drill bit 1,
The rear part of the non-rotating sleeve is provided with a non-rotating sleeve rear centralizing section a, and the front part of the non-rotating sleeve 6 is connected with the front part of the central shaft 25 through a structure with centralizing function;
The drive shaft assembly at least comprises a centralizing sleeve 26, a rear centralizing section accommodating space is formed in the centralizing sleeve 26, the axial length of the rear centralizing section accommodating space is matched with that of a rear centralizing section a of the non-rotating sleeve, the inner diameter of the centralizing sleeve 26 is mutually matched with the outer diameter of the rear centralizing section a of the non-rotating sleeve, the rear centralizing section a of the non-rotating sleeve can be accommodated in the centralizing sleeve, the rear centralizing section a of the non-rotating sleeve can be inserted into the centralizing sleeve 26, the length of the non-rotating sleeve exposed to the outside is shortened, in other words, the axial length of the rear centralizing section accommodating space is slightly larger than that of the rear centralizing section a of the non-rotating sleeve, the rear centralizing section a of the non-rotating sleeve can be accommodated in the centralizing sleeve, and a centralizing bearing can be just placed in the distance between the inner wall of the centralizing sleeve 26 and the outer circumference of the rear centralizing section a of the non-rotating sleeve;
The centralizing sleeve 26 is coaxially connected with the rear centralizing section a of the non-rotating sleeve at least through a centralizing bearing 23, so that the axis of the centralizing sleeve 26 always coincides with the axis of the non-rotating sleeve 6, and the centralizing sleeve 26 is also connected with the rear drill string so as to be capable of performing self-rotation along the axis of the rear drill string under the drive of the rear drill string;
The offset control mechanism is arranged in front of the rear centralizing section a of the non-rotating sleeve and is arranged in the wall of the non-rotating sleeve and used for driving the rotary steering drilling tool to change the track direction of the borehole;
The front end of the central shaft 25 is fixedly provided with a drill bit 1 protruding from the non-rotating sleeve 6, and the rear end of the central shaft is fixedly connected with the centralizing sleeve.
In this embodiment, the centering sleeve 26 is in threaded connection with the centering bearing, torque is transmitted by means of threads, the centering sleeve 26 is fixedly connected with the central shaft 25 through a central shaft mounting position, so that the tail axis of the central shaft 25 is always coincident with the axis of the centering sleeve 26, the central shaft 25 and the centering sleeve 26 can synchronously and automatically rotate under the driving of a rear drill string, the torque is transmitted to the drill bit 1, and the central shaft and the centering sleeve are connected in a polygonal spline threaded manner at the central bearing mounting position.
In this embodiment, as shown in fig. 1-2, the front part of the non-rotating sleeve 6 is connected with the front part of the central shaft 25 through a structure with a centralizing function, which is a focusing centralizing bearing, that is, the front part of the non-rotating sleeve 6 is connected with the front part of the central shaft 25 through the focusing centralizing bearing, and the central shaft 25 can perform self-rotation motion along the axis thereof and simultaneously perform torsion motion relative to the non-rotating sleeve 6 by taking the focusing centralizing bearing 2 as the center;
The bias control mechanism is used for applying a force perpendicular to the axis of the central shaft 25, so that the front part of the central shaft 25 deviates from the axis of the non-rotating sleeve 6, the bit axis deviates from the axis of the non-rotating sleeve, and the drill bit is drilled along the deviation direction of the bit, thereby achieving the purpose of guiding;
The centralizing sleeve 26 is coaxially connected with the rear centralizing section a of the non-rotating sleeve at least through two sets of centralizing bearings 3, and specifically, the first centralizing bearing 23 and the second centralizing bearing 24 can be coaxially connected with the rear centralizing section a of the non-rotating sleeve, or the centralizing sleeve 26 is coaxially connected with the rear centralizing section a of the non-rotating sleeve through at least one centralizing bearing with the length of centralizing surface exceeding the diameter of the rear centralizing section a of the non-rotating sleeve by more than 1.5 times, so as to keep the coaxial relationship between the centralizing sleeve 26 and the non-rotating sleeve 6;
in this embodiment, an outer biasing pushing member 63 is disposed in the wall of the non-rotating sleeve 6, and is used for pushing against the well wall under the action of hydraulic pressure, so as to ensure that the non-rotating sleeve remains substantially stationary relatively.
In this embodiment, the device further comprises an energy transmission device for transmitting electric energy from a power supply circuit 81 arranged in the rear drill string to each electric appliance in the non-rotating sleeve; the energy transfer means comprises energy emitting means 72 and energy receiving means 71; the energy transmitting device is fixedly connected with the centralizing sleeve, and the energy receiving device is fixedly connected with the non-rotating sleeve; the energy receiving device is inserted in the energy transmitting device, and the energy transmitting device is arranged behind the centralizing bearing.
In this embodiment, the power supply circuit 81 is electrically connected to the energy emitting device through an electric wire, the energy emitting device and the energy receiving device transfer electric energy by means of non-contact coupling induction, and the connectable receiving device is electrically connected to each circuit in the non-rotating sleeve including the motor driving circuit through an electric wire.
In this embodiment, a rectifying circuit is further disposed in the non-rotating sleeve, and is responsible for converting alternating current induced in the energy receiving device into direct current, and supplying the direct current to the control module in the non-rotating sleeve, and then the control module distributes the electric energy to a motor driving circuit, where the motor driving circuit is used for driving a motor in a motor pump set of the hydraulic system.
In this embodiment, the focus centering bearing 2 is a spherical bearing.
In this embodiment, a static bias hybrid rotary steerable drilling tool with a sandwich cylinder structure as shown in fig. 1 and 2 comprises a directional bias control mechanism and a pushing bias control mechanism, wherein the directional bias control mechanism is arranged between a focusing centralizing bearing 2 and a first centralizing bearing and sleeved on a central shaft 25, the bias control mechanism comprises a bias cylinder 10 and an inner bias piston 11, the bias cylinder can move along the central shaft in a gap formed by the central shaft and a non-rotating sleeve inner wall, the inner bias piston 11 pushes against the non-rotating sleeve inner wall under the action of a hydraulic system 60, 3-4 inner bias pistons are arranged on the bias cylinder at least along the circumferential direction, and 3-4 inner bias pistons generate a resultant force in a preset direction, and the resultant force can apply a force for deflecting the central shaft so as to enable the central shaft to generate deflection deformation on the driving central shaft, the bias cylinder is connected with the central shaft 25 through a follow-up centralizing bearing 22, and can apply a resultant force to the inner bias piston which is applied to the central shaft 25 between the focusing centralizing bearing and the first centralizing bearing along the axis without affecting the self-rotation motion of the central shaft along the axis.
The pushing type bias control mechanism is arranged in the cylinder wall of the non-rotating sleeve and comprises pushing pieces, the pushing pieces can be abutted against the inner surface of the well wall and can apply pushing force to the well wall, and particularly 3-4 pushing pieces arranged along the well wall can form resultant force pushing the non-rotating sleeve to deflect towards the guiding direction, and finally the rock is laterally cut to the drill bit through the rotary guiding tool, so that the build rate of the rotary guiding tool is increased.
Preferably, the follower centralizer bearing 22 may be a cemented carbide bearing or a PDC bearing.
FIG. 5 is a simplified schematic diagram of an embodiment of the present invention in comparison to a prior art drilling tool rear configuration, wherein FIG. 5A is a schematic diagram of a prior art center shaft and non-rotating sleeve connection; FIG. 5B is a schematic view of the connection of the non-rotating sleeve, the central shaft and the centralizing sleeve after the centralizing sleeve is added in the present invention; d is the outer diameter of the centralizing section after the sleeve is not rotated; as is apparent from fig. 5, in the case that the length of the central shaft 25 remains unchanged, the stress pivot of the flexible deformation of the central shaft 25 is moved backward by adding the centralizing sleeve 26, so that the moment when the central shaft 25 is deformed under stress is also increased, and the working pressure required in the guiding process of the drilling tool is reduced.
In this embodiment, the hydraulic system 60 comprises an electric motor 64, a hydraulic pump 65, a pressure sensor 67 and a corresponding line system comprising a hard pipe, a power fluid line 53, and an electrical connection line 54; the motor rotates under the drive of the motor drive circuit and transmits the rotating power to the hydraulic pump, and the hydraulic pump is used for providing hydraulic pressure for the hydraulic system, and the hydraulic pressure supply biases the piston in the control mechanism so that the piston generates thrust. The variety of hydraulic systems is very large, and this is only an example of this embodiment.
The optional conventional configurations of the other components of the well tool described above as known general components of the well tool are not intended to limit the scope of the present invention, and the replacement of the conventional components of the well tool described above while achieving the same functionality is intended to be within the scope of the present invention.
Another embodiment of the invention: referring to fig. 3, 4 and 5, a push-type static bias rotary steerable drilling tool with a sandwich structure belongs to another structural form of a static bias rotary steerable drilling tool with a sandwich structure in the present invention, and the difference between the present embodiment and the first embodiment of the present invention is that:
the front part of the non-rotating sleeve 6 is connected with the front part of the central shaft 25 through a third centralizing bearing 21;
A front thrust bearing 21-2 and a rear thrust bearing 23-2 are also included for preventing the non-rotating sleeve 6 from falling off the central shaft and assisting in transmitting bending moments and lateral forces.
Further, preferably, a centrally-mounted centering bearing is disposed between the first centering bearing and the third centering bearing, for ensuring stability of the drive shaft, without buckling deformation in the non-rotating sleeve or damage due to vibration.
In this embodiment, the following righting bearing is not required to be added.
The bias control mechanism in this embodiment is a push-leaning bias control mechanism, the bias control mechanism is a hydraulic bias control mechanism, the hydraulic bias control mechanism includes 3-4 outer bias pushing pieces 63 that are circumferentially arranged along the non-rotating sleeve, during the rotation guiding operation, 3-4 outer bias pushing pieces realize the rotation guiding function by generating a resultant force in a specific direction, which is not described here again. The sum of forces applied to the well wall by 3-4 external bias pushing and leaning pieces is larger than 20000N, and the external bias pushing and leaning pieces are used for providing enough sliding friction force between the centralizing sleeve and the non-rotating sleeve for the non-rotating sleeve to enable the non-rotating sleeve to keep relative static to the rear drilling column. The centralizing sleeve 26 is at least coaxially connected with the rear centralizing section a of the non-rotating sleeve through two centralizing bearings 3 with the spacing being more than 2.5 times the diameter of the rear centralizing section a, or the centralizing sleeve 26 is at least coaxially connected with the rear centralizing section a of the non-rotating sleeve through one centralizing bearing with the length exceeding more than 2.5 times the diameter of the rear centralizing section a of the non-rotating sleeve, so as to maintain the coaxial relationship between the centralizing sleeve 26 and the non-rotating sleeve 6, ensure the friction force provided by the pushing piece for preventing the non-rotating sleeve from rotating to be as large as possible, otherwise, the friction force for driving the non-rotating sleeve to rotate by the bearing to be as small as possible so as to realize the slow rotation of the non-rotating sleeve.
Alternative conventional configurations of other components of the well tool of the present invention are also presented in this example: the bias control mechanism can be an external biasing mechanism consisting of an external biasing piston cylinder 61, an external biasing piston 62 and an external biasing pushing piece 63;
although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made therein without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.