A single eccentric push pad rotary guide short section tool and method

Abstract

The present invention discloses a single eccentric push pad rotary guide short section tool and method, comprising a push pad short section, an upper joint, a lower joint, an upper connecting short section, a lower connecting short section, and an eccentric push pad; the push pad short section is provided with a radial opening, a mud channel, a one-way valve, and a discharge valve, the mud channel is connected to the radial opening through the one-way valve and the discharge valve, the eccentric push pad is slidably installed in the radial opening of the push pad and forms a hydraulic chamber; the upper joint is provided with an upper spindle and an upper spindle motor drive mechanism, one end of the upper spindle is connected to the inner wall of the upper connecting short section; the lower joint is provided with a lower spindle and a lower spindle motor drive mechanism, one end of the lower spindle is connected to the inner wall of the lower connecting short section. The present invention can keep the tool housing and the formation approximately stationary in the deflection section through the FOC reverse rotation principle, and use the pressure holding and one-way valve group control to realize the expansion and retraction of the eccentric push pad, thereby achieving the purpose of stable and accurate deflection.

Description

Technical Field

[0001] The invention relates to a single eccentric push pad rotary guide short section tool and method, belonging to the technical field of oil and gas exploration and development. Background Art

[0002] A tribometer is an instrument used to test the friction and wear properties of materials and lubricants under given conditions. Based on their motion, tribometers can be categorized into various types, including reciprocating and fretting. Research on their tangential stiffness has been a focus of considerable research.

[0003] To date, domestic and international research on fretting wear has focused on the effects of displacement amplitude, load, and frequency on fretting wear behavior. The impact of system stiffness on fretting wear test results has rarely been studied. Testing methods for friction and wear testing machine system stiffness remain unstandardized, and relevant technical standards have yet to be established. Furthermore, research on friction and wear testing machine system stiffness is also limited. In response to this situation, innovative research and application of tangential stiffness testing methods are needed. The development of a set of tools and methods suitable for single-eccentric push-pad rotary guide subs is of great significance to the academic community. Summary of the Invention

[0004] In order to overcome the defects in the prior art, the present invention aims to provide a single eccentric push pad rotary guide short section tool and method.

[0005] The present invention solves the above technical problems and provides a technical solution: a single eccentric push pad rotary guide short section tool, comprising a push pad short section, an upper joint, a lower joint, an upper connecting short section, a lower connecting short section, and an eccentric push pad;

[0006] The push-pull sub has a radial opening, a mud channel, a one-way valve, and a discharge valve. The mud channel is connected to the radial opening through the one-way valve and the discharge valve. The eccentric push pad is slidably installed in the radial opening of the push-pull sub to form a hydraulic chamber. An activation valve is provided at the lower end of the mud channel.

[0007] The lower ends of the pushing short section are respectively connected to the upper connecting short section and the lower connecting short section, and the upper joint and the lower joint are respectively connected to the upper connecting short section and the lower connecting short section, and the upper joint and the upper connecting short section, and the lower joint and the lower connecting short section are both rotated;

[0008] An upper spindle and an upper spindle motor drive mechanism are provided in the upper joint, and one end of the upper spindle is connected to the inner wall of the upper connecting short section; a lower spindle and a lower spindle motor drive mechanism are provided in the lower joint, and one end of the lower spindle is connected to the inner wall of the lower connecting short section.

[0009] A further technical solution is that a roller is provided on the outer surface of the eccentric push pad.

[0010] A further technical solution is that the outer surface of the eccentric push pad is provided with a low friction material layer.

[0011] A further technical solution is that a posture measurement module, a dual-group FOC control module and a power supply module are provided inside the push-pull short section.

[0012] A further technical solution is that an electronic compartment for accommodating a posture measurement module, a dual-group FOC control module and a power supply module is provided inside the push-pull sub.

[0013] A further technical solution is that the attitude measurement module includes a gyroscope, an accelerometer, an azimuth sensor and an encoder, which are used to obtain the short section attitude, well inclination and azimuth data, and feed it back to the dual-group FOC control module in real time.

[0014] A further technical solution is that a boss is provided on the outer wall of the lower end of the eccentric push pad, and a groove is provided on the inner wall of the radial opening to cooperate with the boss. A spring is sleeved on the eccentric push pad, and the lower end of the spring is pressed on the boss, and the upper end is pressed on the upper top surface of the groove.

[0015] A single eccentric push pad rotation guide method, the specific steps are as follows:

[0016] Step S1, initialization and pattern recognition: When the drill string is lowered into the target well section and is ready to start directional deflection, the surface and downhole control systems first complete the initialization handshake;

[0017] Step S2: Target parameter issuance: Surface engineers set the required well inclination increase rate and azimuth adjustment amount for this well section through measurement while drilling and wellbore trajectory design;

[0018] Step S3, centering and positioning: The control system drives the push-pull sub to begin rotating relative to the main shaft, using the FOC motor to precisely control its angle. Next, the control system gradually closes the activation valve at the bottom of the sub to initiate the pressure-holding process. Mud pressure begins to increase at the front end of the hydraulic chamber, preparing to push the pad out.

[0019] Step S4, eccentric push pad extension: when the pressure reaches a controllable threshold, PWM is used to push the eccentric pad out in stages;

[0020] Step S5, rhythmic pushing control: During the continuous drilling process, the system continuously cycles between "anchoring force application" and "release adjustment" according to a predetermined adaptive rhythmic strategy;

[0021] Step S6, working mode switching: When the sensor detects an abnormal increase in borehole friction, the system automatically switches to non-contact pushing mode: the pads are quickly retracted, and the lateral jet channel is opened at the same time, using high-pressure mud jets to clear well wall obstacles and provide temporary lateral force; when the well wall stabilizes, the mechanical pad pushing is resumed;

[0022] Step S7, stop the tool after drilling: When the target well inclination and azimuth are reached or the deflection task of this section is completed, the ground sends a command to end the steering mode; the control system gradually reduces the pad thrust and enters the standby cruise state, waiting for the next steering command or until drilling.

[0023] The present invention has the following beneficial effects: the present invention can keep the tool housing and the formation approximately stationary through the FOC reverse rotation principle in the deflection section, and use the pressure holding and one-way valve group control to realize the expansion and retraction of the eccentric push pad, thereby achieving the purpose of stable and precise deflection. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a three-dimensional cross-sectional view of the device of the present invention;

[0025] Figure 2 A three-dimensional diagram of the device of the present invention;

[0026] Figure 3 is a three-dimensional stereogram of the upper joint;

[0027] Figure 4 A three-dimensional diagram of the main axis;

[0028] Figure 5 A three-dimensional diagram of an activated valve;

[0029] Figure 6 This is the cross-sectional view of the lower connecting short section;

[0030] Figure 7 is a cross-sectional view of the lower joint;

[0031] Figure 8 It is a cross-sectional view of the push-pull sub;

[0032] Figure 9 A three-dimensional image of an eccentric push cushion. DETAILED DESCRIPTION

[0033] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0034] like Figures 1-9As shown, a single eccentric push pad rotary guide short section tool of the present invention comprises a push pad short section 1, an upper joint 2, a lower joint 3, an upper connecting short section 4, a lower connecting short section 5, and an eccentric push pad 6;

[0035] The push-pull sub 6 has a radial opening, a mud channel 7, a one-way valve 8, and a discharge valve 9. The mud channel 7 is connected to the radial opening through the one-way valve 8 and the discharge valve 9. The eccentric push pad 6 is slidably installed in the radial opening of the push-pull sub 1 to form a hydraulic cavity. The mud channel 7 injects liquid into the hydraulic cavity through the one-way valve 8, and the hydraulic cavity discharges the liquid into the mud channel 7 through the discharge valve 9. An activation valve 10 is provided at the lower end of the mud channel 7.

[0036] The lower ends of the push-pull sub 1 are connected to the upper connecting sub 4 and the lower connecting sub 5 respectively, and the upper joint 2 and the lower joint 3 are connected to the upper connecting sub 4 and the lower connecting sub 5 respectively. The upper joint 2 and the upper connecting sub 4, and the lower joint 3 and the lower connecting sub 5 are rotated in opposite directions.

[0037] An upper spindle 11 and an upper spindle motor drive mechanism are provided in the upper joint 2, and one end of the upper spindle 11 is connected to the inner wall of the upper connecting short section 4; a lower spindle 12 and a lower spindle motor drive mechanism are provided in the lower joint 3, and one end of the lower spindle 12 is connected to the inner wall of the lower connecting short section.

[0038] In the present invention, the push-pull sub 1 is the outer frame of the tool, which has the function of achieving reverse rotation with the internal main shaft, and has an opening on its side wall for installing an eccentric push-pull pad;

[0039] The main shaft is located inside the short section housing and is responsible for transmitting torque and forming relative rotation with the housing;

[0040] The eccentric push pad 6 is installed at the opening of the side wall of the short section housing. Only one piece is provided. Its outer surface can be made of rollers or low-friction materials to reduce wear when in contact with the well wall and improve the pushing efficiency.

[0041] The bottom of the radial opening is connected to the inner cavity of the eccentric push pad 6, and is used to push or retract the push pad by means of the pressure holding principle;

[0042] The control system includes the following submodules: an attitude measurement module, which integrates a gyroscope, accelerometer, azimuth sensor, and encoder to collect downhole attitude, inclination, and azimuth data in real time; a dual-group FOC control module, which adjusts based on attitude data to achieve synchronous, counter-directional (or opposite-direction) rotation of the sub's housing and internal spindle; and a motor, which drives the housing and spindle, achieving closed-loop control through coordination with a transmission mechanism (such as gears or belt drives).

[0043] Activation valve 10: It is located at the lower end of the sub housing and is used to close the mud flow channel and generate pressure build-up during deflection;

[0044] One-way valve 8: automatically opens when the mud pressure reaches the set value, introducing the mud into the hydraulic chamber;

[0045] Discharge valve 9: used to discharge the mud in the hydraulic cavity when recovery is required, so as to realize the automatic retraction of the push pad.

[0046] In this embodiment, the preferred implementation is: a boss is provided on the outer wall of the lower end of the eccentric push pad, a groove is provided on the inner wall of the radial opening to cooperate with the boss, and a spring is provided on the eccentric push pad, the lower end of the spring is pressed on the boss, and the upper end is pressed on the upper top surface of the groove.

[0047] The present invention provides a single eccentric push pad rotation guidance method, which utilizes intelligent materials to optimize the pad support characteristics, adopts an adaptive rhythmic control algorithm to dynamically adjust the push cycle, integrates a bionic-inspired alternating anchoring strategy, combines multi-sensor information to achieve multi-dimensional parameter fusion control, introduces an energy-saving reaction mechanism to reduce energy consumption, and provides lateral force through non-contact pushing means in special circumstances.

[0048] The entire method can form a complete "device + method" solution with the original short-section tool, and has significant application advantages in deep well and horizontal well directional drilling.

[0049] 1. Principle of intelligent material control: This method introduces intelligent materials into the hydraulic actuator of the eccentric push pad to enhance control accuracy and responsiveness.

[0050] Magnetorheological fluid (MR liquid) is used as the working medium in the hydraulic cavity of the eccentric push pad, and an electromagnetic coil controller is installed around the cavity. When the control system applies magnetic fields of different intensities, the viscosity of the MR liquid changes rapidly, thereby adjusting the equivalent stiffness and damping of the hydraulic cavity in real time. When rigid pushing is required, the magnetic field is increased to rapidly thicken the liquid, locking the position of the pad to form a similar "semi-active support"; when buffering or adjustment is required, the magnetic field is weakened to thin the liquid, allowing the pad to produce slight displacement relative to the well wall to buffer vibrations and adapt to wellbore irregularities. Through the application of this intelligent material, the lateral support force of the eccentric pad can be finely controlled, which not only ensures sufficient guiding force but also avoids impact loads caused by excessive rigidity.

[0051] This principle, similar to the application of magnetorheological damping suspension technology in automobiles to drilling tools, enables adaptive adjustment of the pad's support characteristics. Furthermore, smart materials can be applied to the pad's surface. For example, shape memory alloy inserts can be used to modify the pad's surface morphology or friction coefficient at different temperatures, automatically improving wear resistance or changing contact stiffness in high-temperature well sections. These smart material approaches do not alter the macrostructure of the original pad or hydraulic chamber; instead, they upgrade the materials and media, achieving performance improvements while preserving the original structure.

[0052] 2. Adaptive rhythm control principle: Adaptive rhythm control refers to dynamically adjusting the periodic pattern of eccentric pad pushing according to downhole working conditions and trajectory requirements.

[0053] This method incorporates a cyclical, alternating push-and-release strategy: within a deflection cycle, the eccentric pad actively presses against the wellbore wall to provide lateral force during specific periods (the "anchoring" phase), while slightly reducing thrust or partially retracting during other periods (the "release" phase). The anchoring phase ensures corrected drill bit orientation and increased wellbore inclination, while the release phase provides a brief "respite" for the downhole tool, alleviating static friction and wear caused by the continuous pressure. This push-and-release rhythm is not fixed but adaptively adjusted by the control system based on actual conditions. For example, when sensors detect that the wellbore trajectory has reached the expected curvature and friction is rapidly increasing, the release period can be extended to reduce frictional resistance. Conversely, when greater deflection force is required, the release phase can be shortened, the anchoring period can be lengthened, or thrust can be increased. The core of adaptive rhythmic control is to avoid prolonged, continuous sliding friction. By cyclically switching the contact state between static and dynamic friction, the high friction that could otherwise accumulate is distributed, thereby reducing drag and the risk of stiction. This is somewhat similar to the biomimetic movement of earthworms and moles: as they advance through the soil, earthworms rhythmically expand and contract their front and rear bodies, alternating between anchoring and sliding, to overcome friction. This tool uses pads to alternately push against and yield to reduce the "stick-slip" effect during drill string rotation and deflection. This rhythmic control also mitigates impacts caused by uneven wellbore walls or varying lithology, protecting the tool and improving deflection stability.

[0054] 3. Bionic-Inspired Alternating Anchoring Principle: To further optimize the steering effect, this method strategically draws inspiration from the natural excavation motion and employs an alternating anchoring and adjustment principle. Similar to a mole using its claws to stabilize its body while adjusting its digging direction, this steering method utilizes an eccentric pad as a "bionic anchor point." During the anchoring phase, the pad acts as a fulcrum on the wellbore wall, which the subshell uses to resist drillstring torque and maintain its position. Subsequently, during the release phase, the control system allows the subshell to undergo minor rotations or position adjustments relative to the formation (within a few degrees, maintaining the overall toolface orientation within the target). This is similar to how an organism, when turning underground, first stabilizes a certain part of its body and then twists its "waist" to change direction. Specifically, the FOC motor applies reverse torque to stabilize the shell during the anchoring phase, then reduces the torque during the release phase to allow the shell to fine-tune with the drillstring's direction. The torque is then quickly reversed again to stabilize the shell. Since the eccentric pad is in continuous contact with the wellbore wall, this fine-tuning will not cause the tool to become completely unstable, but will allow slight slippage to adjust the anchoring position. This bionic alternating anchoring method ensures that each time the pad reapplies the lateral force, it can act on a new part of the wellbore wall in the most effective manner, avoiding local extrusion or wear caused by long-term pressure on the same point. In addition, multiple cycles of fine-tuning also make the deflection process smoother, and will not cause the wellbore trajectory to be partially out of round or the tool to be stuck due to single-point anchoring for too long. In this process, the short section housing, main shaft, motor and eccentric pad work closely together: the main shaft drives the drill bit to rotate and cut continuously, the short section housing is anchored by the pad to maintain orientation, and the motor is temporarily unloaded or loaded as needed to cooperate with the pad shift, and then quickly stabilized.

[0055] 4. Multi-Dimensional Parameter Fusion Control Principle: To achieve precise execution of the adaptive rhythmic and biomimetic alternating anchoring described above, this method relies on a powerful multi-dimensional parameter fusion control system. This control system integrates data from multiple sensor sources, including but not limited to: real-time wellbore inclination and azimuth provided by the attitude measurement unit (gyroscope / accelerometer), contact load feedback from pad hydraulic pressure and displacement sensors, rock formation characteristics at the drill bit (such as rock hardness or gamma value measured while drilling), and drillstring mechanical parameters (such as downhole torque, WOB weight index, and vibration acceleration). By integrating this data, the system acquires a comprehensive understanding of the current drilling status. For example, if the sensor fusion results indicate that the wellbore inclination growth rate is below the target and the rock formation is soft, the control algorithm will increase the push force or extend the anchoring phase. If severe vibration and torque fluctuations are detected, indicating excessive friction or encountering hard formations, the algorithm will automatically increase the release frequency to reduce impact. Furthermore, this fusion control system incorporates adaptive algorithms (such as fuzzy control or reinforcement learning models) to enable the system to continuously optimize parameters based on historical data. In other words, the tool "learns" as it works during drilling, continuously revising the model that correlates thrust force and trajectory changes, achieving increasingly precise control. This closed-loop control logic, incorporating multi-dimensional parameters, ensures the reliability and real-time adaptability of the guidance method. Regardless of changing downhole conditions, the system can comprehensively assess and adjust its strategy to consistently maintain the intended trajectory. Furthermore, the control system incorporates built-in redundancy and fault tolerance: if a sensor's data is abnormal, information from other dimensions can be relied upon to maintain control decisions and prevent loss of control.

[0056] 5. Energy-saving Reaction Mechanism Principle: Given the limited downhole power supply, this method emphasizes efficient energy utilization, reducing motor load and hydraulic energy consumption through an energy-saving reaction mechanism. The principle is to fully utilize passive reaction forces to replace active energy consumption during the generation and maintenance of guiding force. When the eccentric pad is anchored against the wellbore wall, the friction between the pad and the wall naturally generates a reaction torque, which partially offsets the rotational torque transmitted from the main drill string to the sub's casing. This method cleverly exploits this fact: during the pad anchoring phase, the control system reduces the output of the FOC motor, allowing the pad's own friction to take on the primary role in stabilizing the casing. Only when the casing begins to slip relative to the wellbore wall (indicating that friction is insufficient to fully balance the torque) does the motor initiate torque compensation to stabilize the sub. In this way, the torque required to maintain orientation is passively provided by the wellbore reaction force for the majority of the time, while the motor remains in low power standby mode, intervening only briefly when necessary for correction. This is similar to utilizing gravity when pedaling uphill (using the motor to apply force) and gliding along (using the reaction force) on flat or downhill terrain. At the same time, during the release phase, when the pad slightly moves away from the wellbore wall, the housing rotates slightly relative to the drill string. At this point, the motor can even switch to a dynamic braking mode, converting the brief reverse sliding kinetic energy into electrical energy and recycling it to the battery storage unit (e.g., utilizing the principle of motor regenerative braking). Furthermore, the hydraulic "holding pressure" process for driving the pad extension has been optimized: Traditional methods require closing an activation valve to accumulate sufficient mud pressure before opening a check valve to push the pad. This solution, combined with MR fluid technology, precisely controls the valve opening and closing rhythm to avoid wasteful pressure overshoot. For example, when the pad approaches the target extension position, magnetorheological fluid is used to increase damping and reduce the speed of the outflow. Once the position is reached, the check valve is immediately closed to lock the pressure, eliminating the need for continuous high-pressure fluid supply and thus saving pump power. In summary, the energy-saving reaction mechanism significantly improves the system's energy efficiency through passive force utilization and energy recovery, allowing the directional tool to maintain sufficient power and controllable temperature rise even during long-term operation.

[0057] 6. Non-contact Pushing Principle: For certain special working conditions (such as extremely unstable and fractured well walls, where direct contact must be avoided to prevent lost circulation), this method provides a non-contact pushing auxiliary steering mode. Non-contact pushing relies on a directional hydraulic jet to apply lateral force. The principle is to generate a high-speed mud jet near the lateral opening where the eccentric pad is located. The fluid dynamic pressure difference is used to "blow" the tool in the opposite direction to change the direction of the drill bit.

[0058] Specifically, the existing hydraulic chamber and pad structure can be utilized. When non-contact mode is required, the control system retracts the eccentric pad or slightly suspends it a few millimeters from the wellbore wall. Simultaneously, a special bypass channel opens, allowing some drilling fluid to flow through a small nozzle or orifice at the pad opening. (This modification does not alter the main structure; only micro-holes are machined in the pad or casing.) Due to the high mud pumping flow rate, once it reaches this side orifice, a powerful lateral jet is formed, impinging on the wellbore wall. According to Bernoulli's principle, the jet creates a high-pressure area on the pad side and a relatively low-pressure area on the opposite side of the tool, generating a net lateral force that pushes the tool toward the low-pressure side. By controlling the on / off and flow rate ratio of the side jet, the drill string can be adjusted without direct contact with the wellbore wall. It is worth noting that non-contact push-pull mode is generally used only as an auxiliary mode: during conventional deflection, mechanical pad pressure is still the primary method, supplemented by jet flow. Only when the wellbore wall is extremely sensitive or when it is necessary to temporarily loosen the tool is the full jet flow control mechanism temporarily switched to direct flow. This method achieves a "water cushion"-like pushing effect—similar to adding a layer of high-speed fluid lubrication between the pad and the wellbore wall, transforming the pushing action from frictional contact to hydrodynamic action. Its advantage is zero friction and wear, which prevents mechanical disturbance of the wellbore wall. However, given the limited thrust of the jet, this method is used in conjunction with mechanical pushing to achieve both precise deflection and wellbore protection.

[0059] In summary, the working principle of this steering method is an extension and enhancement of the original single-eccentric pad RSS tool guidance mechanism: it continues to utilize the essential mechanism of direct force applied by a single pad to change the drill bit's direction, but through intelligent materials and advanced control, this force application method is made more controllable, flexible, and energy-efficient. Under specific conditions, fluid dynamics are used to achieve contactless steering. Throughout the process, the original structural relationship between the short-section housing, main shaft, eccentric pad, hydraulic chamber, and control system is maintained, but the interaction is more intelligent: the main shaft still transmits drilling torque, the short-section housing still performs the steering deflection function, the eccentric pad remains the point of application of lateral force, the hydraulic chamber still provides the pad's power source, and the control system becomes a smarter brain to coordinate the actions of all parts. It is this approach of maintaining the same structure and innovative methods that has enabled us to achieve a performance leap on the existing tool platform.

[0060] The specific process of the present invention is as follows:

[0061] Step 1. Initialization and pattern recognition: When the drill string is lowered into the target well section and is ready to start directional deflection, the ground and downhole control systems first complete the initialization handshake. The short section control system self-checks the status of each sensor and actuator to confirm that the eccentric pad is in the retracted position, the hydraulic cavity pressure is normal, the MR liquid magnetic control system is working properly, and the motor has sufficient energy storage. At the same time, the current well section working conditions (such as vertical well section, deflection section, stable deflection section, etc.) are judged based on the measurement data. If it is determined that a well section that requires deflection is entered, the system will switch to the "guided active mode"; if it is still in the vertical well section, the "vertical well passing mode" will be maintained. In this mode, the short section housing and the main shaft are temporarily locked and rotated synchronously, and no lateral force is actively applied. In this example, it is assumed that the deflection section has been entered, so the system enters the guided mode on standby.

[0062] Step 2. Issue target parameters: Ground engineers set the required well inclination increase rate and azimuth adjustment amount for this well section through measurement while drilling and design of wellbore trajectory. This instruction is sent to the downhole short section control system through mud pulse telemetry or wired transmission. The control system reads the target parameters, such as the required inclination rate of 3° / 30m, azimuth turn 15° to the right, etc., and then calculates the direction and approximate amplitude of the lateral force to be applied based on the currently measured well inclination / azimuth. At this point, the control system specifies the "target tool face direction" (the position of the eccentric pad relative to the high side) and the "pushing force strategy". For example, it may decide that the pad should point to a certain angle to the right of the low side of the wellbore, and a medium to strong thrust is required to achieve the required trajectory change.

[0063] Step 3: Centering and positioning: The control system drives the sub housing to start rotating relative to the main shaft, using the FOC motor to precisely control its angle. Using the gyro / magnetic compass as a reference, the housing is rotated to a position where the eccentric pad points to the predetermined tool face direction. Since the inclination and pushing have not yet begun at this point, the drill string is rotating as a whole. The control system will adopt a short dynamic centering strategy: that is, while the drill string is continuously rotating, the motor rotates in the opposite direction at a speed slightly higher than the drill string speed to stabilize the housing in the target direction. After reaching the position, the housing remains stationary relative to the formation or rotates slowly within ± a few degrees, thereby locking the tool face. Next, the control system gradually closes the activation valve at the bottom of the sub to start the pressure holding process. Mud pressure begins to rise at the front end of the hydraulic chamber, preparing to push the pad out.

[0064] Step 4: Pad Extension: When pressure reaches a controllable threshold, the control system does not simply fully open the check valve all at once as in traditional methods. Instead, it uses PWM (pulse width modulation) or proportional valve control technology to push the eccentric pad out in stages. First, the check valve is slightly opened to allow a small amount of high-pressure mud to enter the hydraulic chamber, causing the pad to slowly extend and contact the wellbore wall. During this stage, the MR fluid's low viscosity provides cushioning, allowing the pad to contact the wellbore wall at a steady pace rather than violently impacting it. Sensors detect initial pad contact (signals of a sudden pressure surge and cessation of displacement), and the control system temporarily halts slurry feed, waiting for the casing to stabilize. The main push phase then begins: the controller reopens the valve to increase pressure, further extending the pad to the desired thrust or displacement. During this process, the MR fluid's magnetic field gradually strengthens, increasing damping and preventing oscillation. When the preset thrust force (determined by the hydraulic pressure sensor) is reached or the pad's travel limit is reached, the control system closes the check valve to lock pressure, securing the pad in its current extended position. At this point, the eccentric pad is firmly against the wellbore wall, entering an anchored state. The drill bit deflects in the desired direction and begins cutting the formation, achieving deflection.

[0065] Step 5: Rhythmic Push Control: During continuous drilling, the system continuously cycles between "anchoring force application" and "release adjustment" according to a predetermined adaptive rhythmic strategy. Specifically, for example, a cycle is executed every 360° of rotation (or at a desired rhythmic frequency)—during approximately 270°, the eccentric pad maintains anchoring force (the FOC motor continuously provides counter-torque to keep the casing stationary), followed by release adjustment at approximately 90° (the motor torque is reduced to allow the casing to slide slightly, and the MR fluid's viscosity decreases, allowing the pad to slightly cushion and retract a few millimeters). This ratio and duration are not constant but are adjusted in real time by the control system. The control system continuously collects data: if the build rate is insufficient, the release time may be shortened or the retraction amplitude may be reduced to increase the average lateral force; conversely, if friction increases dramatically or micro-oscillations occur, the release time or amplitude is increased to restore the system to balance. Throughout the entire cycle, formation feedback parameters (such as trajectory changes measured while drilling) are also taken into account. After several cycles, the control system evaluates the actual well inclination and azimuth deviation, fine-tuning the target toolface direction or thrust as necessary before entering the next optimization cycle. Through this closed-loop regular control, the drilling trajectory is continuously brought back to the planned curve.

[0066] Step 6: Switching Operating Modes: If a special situation arises during drilling, such as wellbore collapse causing pads to sink into soft mud and lose support, or if sensors detect an abnormally high level of borehole friction (possibly indicating sticking), the control system triggers appropriate response procedures. For example, if pads resisting the collapsing mud cake fail to generate the desired deflection, the system can automatically attempt to switch to non-contact push mode: rapidly retracting the pads (opening the bleed valve to release pressure, causing the pads to retract under spring action). Simultaneously, the lateral jet channel opens, using a high-pressure mud jet to clear the wellbore obstruction and provide a temporary lateral force. Once the wellbore stabilizes, mechanical pad push is resumed. Alternatively, if a significant stick-slip trend is detected, the system will increase the frequency of pad releases or even temporarily release them completely, allowing the drill string to rotate a few revolutions to restore power before re-anchoring the steering. The entire process is autonomously completed by the control system, requiring no human intervention, though status updates are provided to the surface. Furthermore, if a well section transition occurs (for example, from a build-up section to a stable or even horizontal section), the system smoothly adjusts its strategy based on pre-set settings: reducing the build-up force or relocking the casing / spindle to synchronize rotation to avoid unnecessary lateral forces. These operational procedures ensure smooth transitions and uninterrupted operation in various well conditions.

[0067] Step 7. Stop the tool after drilling: When the target well inclination and azimuth are reached or the inclination task of this section is completed, the ground sends a command to end the steering mode. The control system gradually reduces the thrust of the pad: first enters the release stage to release the anchor, then opens the discharge valve to slowly release the pressure, allowing the mud in the hydraulic chamber to be discharged through the annulus, and the pad retracts to the retracted position under the action of the spring reset force. At the same time, the FOC motor stops the reverse torque output, so that the short section housing rotates synchronously with the main shaft again. At this time, the tool returns to a part of the conventional drill string. Finally, the control system records all the data of this section (for subsequent analysis or self-learning), enters the standby cruise state, and waits for the next steering instruction or until drilling is started.

[0068] The subshell housing still acts as a carrier of the guiding force, transmitting lateral forces to the wellbore wall via eccentric thrust pads. However, unlike traditional systems where the housing remains stationary, the housing undergoes regular micro-rotations and re-anchoring under adaptive rhythmic control. Integrated attitude sensors (magnetic compass and accelerometers) provide real-time feedback to the control system regarding the housing's orientation and motion, enabling the control system to accurately determine whether the housing remains in the target orientation or is slipping. The bearing assembly between the housing and the internal main shaft is designed to withstand alternating torque and periodic micro-vibration. Damping structures (such as particles added to the bearing lubricant) are used as necessary to prevent high-frequency resonance. Eccentric thrust pads and possible jet micro-holes are installed at the openings on the housing surface. Their structure must increase the flow channel while ensuring strength. Overall, the subshell serves as both an actuator (the active component that translates control commands into physical thrust) and a sensing hub (its motion influences control decisions) within the coordinated mechanism.

[0069] Internal spindle: The spindle still transmits drillstring rotation to the drill bit and serves as the drilling power channel. Since the sub housing may rotate in the opposite direction or slightly vibrate relative to the spindle, universal joints or flexible connections ensure that this relative motion does not affect the drill bit speed. Sensors are typically installed on the spindle to measure weight-on-bit and torque (or inferred from changes in motor current). This data is fed into the control system to determine the effectiveness of the pad anchoring. For example, when the pad is effectively anchored, spindle torque fluctuations decrease and the effective weight-on-bit effect increases. Conversely, if the pad slips, the spindle torque may drop sharply. The relative rotation angle between the spindle and the housing is monitored by an encoder. If the housing deviates from relative static, the encoder signal, combined with gyroscope data, is fed back to the motor to adjust the torque to rebalance. This creates a negative feedback control pair between the spindle and the housing: the spindle drives the drill bit forward, while the housing deflects to correct the direction. The dynamic interaction between the two is balanced by the control system, much like the coordination between the pedals (spindle) and handlebars (housing) on ​​a bicycle to maintain forward direction.

[0070] Eccentric Push Pads: The eccentric pads act as the "finger" upon which the guiding force is applied. While the new method maintains its structure (single eccentric retractable pads), its operation is more diverse. First, the hydraulic cavity on the pad's inner surface is filled with magnetorheological fluid, which offers variable stiffness and damping characteristics compared to traditional hydraulic oil and is controlled in real time by the control system. The pad is connected to the cavity via a hydraulic piston, which incorporates displacement and pressure sensors to precisely measure the pad's extended position and applied force. Anti-friction rollers or low-friction materials can still be installed on the pad's surface to reduce contact friction. Furthermore, the new method further reduces pad surface wear by incorporating fluid lubrication and periodic release. Several tiny nozzles on the pad (which can be configured in conjunction with the rollers) spray slurry when needed, creating hydraulic thrust. This requires an internal design to direct a portion of the fluid flow to the nozzles. This can be accomplished by creating a bypass hole in the pad's piston. When the piston is aligned in a specific position, high-pressure slurry is directed to the nozzles at the front of the pad. Normally, when the piston is not in this position, the nozzles are deactivated, without affecting normal hydraulic function. The new design also optimizes the eccentric spacer's spring return mechanism: a shape memory alloy spring replaces a conventional spring, ensuring sufficient return force even at elevated temperatures (due to motor heating or ambient heat) to prevent creep failure. During operation, the spacer, housing, and hydraulic chamber together form a push-to-pull actuator, generating thrust or retracting in response to control system commands. It provides rigid support during anchoring, allows for smooth yielding during release, and acts as a hydraulic nozzle seat in jet mode, offering both versatility and reliability.

[0071] Hydraulic chamber and valve block: The hydraulic chamber and its valve block are the power unit that drives the pad's extension and retraction. The hardware structure retains the original design, including the activation valve, one-way valve, and discharge valve pathways. In the new approach, the valve block's control is more refined: the activation valve is pulse-controlled and can be partially opened and closed to adjust the pressure buildup rate; the one-way valve has been electronically assisted in opening and closing (solenoid control is connected in parallel to the traditional hydraulic self-adaptive system to achieve PWM flow regulation); and the discharge valve has been added with an adjustable throttle to control the pressure relief rate and prevent the pad from suddenly retracting and impacting. The magnetorheological fluid in the hydraulic chamber requires a magnetic field generator—a high-temperature resistant coil can be wound around the outer wall of the chamber, with the control system supplying power to control the strength of the magnetic field. The entire hydraulic drive module plays the role of "muscle and tendon" in the coordinated mechanism: according to the "nerve signals" (electrically controlled valve commands, coil current, etc.) sent by the control system, the corresponding mechanical displacement and force are generated. It is worth emphasizing that the module maintains its inherent reliability by simplifying the multi-channel design, and the introduction of smart materials and electronic controls does not significantly increase leakage or failure points - because the main hydraulic pathway remains single, and the electronically controlled valve maintains the function of the original hydraulic valve when it fails, preventing loss of control.

[0072] FOC motor and control system: The motor and control system are the brains and core of the new approach. The FOC motor provides the power for the counter-rotation of the subhousing and the main shaft, and its control accuracy directly determines the stability of the subhousing's attitude. The new approach utilizes advanced control algorithms (such as feedforward and feedback control) to enable the motor to apply precise torque to offset drillstring torque during anchoring and quickly respond to fine-tuning during release to achieve tracking control. The motor controller is highly integrated with the sensor fusion algorithm, adjusting the motor current based on gyroscopic and encoder data in millisecond cycles to control subhousing motion synchronously or asynchronously. The control system includes an embedded industrial computer running a real-time operating system to process all sensor data and actuator commands. It has built-in state machines for various control modes: normal steering, adaptive rhythm, abnormal operating conditions, jet flow mode, and vertical well mode, switching logic upon receiving trigger conditions. The control system also communicates with the surface to receive commands and upload data. In this collaborative mechanism, the control system is undoubtedly the decision-making center, but it also forms an information and energy cycle with various downhole components: sensors feed component status back to the control system, which then calculates and outputs it to the motor and valve block to influence component movement. Component movement, in turn, changes the drilling state, which is captured by sensors... This cycle continues, forming a closed-loop collaborative system. It's worth noting that the control system's software algorithm itself is also a key component, ensuring the reliability and optimization of hardware collaboration through advanced software fault tolerance and self-adaptation.

[0073] Overall, the coordinated mechanism among the components in this guidance method is characterized by distinct functions, dynamic coupling, and intelligent coordination. The stub housing / spindle provides the mechanical framework, the pad / hydraulic actuator outputs the lateral force, and the motor / controller coordinates the direction and magnitude of that force in real time. Compared to traditional RSS, the single eccentric pad structure simplifies redundant components, making coordination more straightforward. Furthermore, by imbuing the control "brain" with intelligence, the entire system works seamlessly, like biological function.

[0074] In summary, this invention integrates intelligent material technology, advanced control algorithms, and biomimetic mechanics to significantly improve the accuracy, efficiency, and reliability of directional drilling. It demonstrates particular advantages in demanding environments such as deep and ultra-long horizontal wells, helping oil and gas development reach target formations more safely and efficiently. This technical solution, while simplifying complexity and outperforming others through intelligent approaches, fully leverages the power of innovative methods, elevating existing rotary steerable tools to a new level and bringing revolutionary application prospects to the field of directional drilling.

[0075] The above description does not limit the present invention in any form. Although the present invention has been disclosed through the above embodiments, it is not intended to limit the present invention. Any technician familiar with the profession can use the technical content disclosed above to make some changes or modifications to equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are within the scope of the technical solution of the present invention.

Claims

1. A single eccentric push pad rotary guide short section tool, characterized in that: It includes a push-and-leave nipple, an upper joint, a lower joint, an upper connecting nipple, a lower connecting nipple, and an eccentric push-and-leave pad; The push-pull sub has a radial opening, a mud channel, a one-way valve, and a discharge valve. The mud channel is connected to the radial opening through the one-way valve and the discharge valve. The eccentric push pad is slidably installed in the radial opening of the push-pull sub to form a hydraulic chamber. An activation valve is provided at the lower end of the mud channel. The lower ends of the pushing short section are respectively connected to the upper connecting short section and the lower connecting short section, and the upper joint and the lower joint are respectively connected to the upper connecting short section and the lower connecting short section, and the upper joint and the upper connecting short section, and the lower joint and the lower connecting short section are both rotated; The upper joint is provided with an upper spindle and an upper spindle motor drive mechanism, and one end of the upper spindle is connected to the inner wall of the upper connecting short section; the lower joint is provided with a lower spindle and a lower spindle motor drive mechanism, and one end of the lower spindle is connected to the inner wall of the lower connecting short section; The push-pull sub is internally provided with an attitude measurement module, a dual-group FOC control module and a power supply module; The attitude measurement module includes a gyroscope, an accelerometer, an azimuth sensor and an encoder, which is used to obtain the short-section attitude, well inclination and azimuth data, and feed it back to the dual-group FOC control module in real time; The outer wall of the lower end of the eccentric push pad is provided with a boss, the inner wall of the radial opening is provided with a groove matching the boss, and a spring is sleeved on the eccentric push pad, the lower end of the spring is pressed on the boss, and the upper end is pressed on the upper top surface of the groove.

2. A single eccentric push pad rotary guide short section tool according to claim 1, characterized in that: The outer surface of the eccentric push pad is provided with a roller.

3. A single eccentric push pad rotary guide short section tool according to claim 1, characterized in that: The outer surface of the eccentric push pad is provided with a low friction material layer.

4. A single eccentric push pad rotary guide short section tool according to claim 1, characterized in that: An electronic compartment for accommodating a posture measurement module, a dual-group FOC control module and a power supply module is provided inside the push-pull sub.

5. A single eccentric push pad rotation guide method, characterized in that: The method uses a single eccentric push pad rotary guide short section tool as described in any one of claims 1 to 4 for guidance, and the specific steps are as follows: Step S1, initialization and pattern recognition: When the drill string is lowered into the target well section and is ready to start directional deflection, the surface and downhole control systems first complete the initialization handshake; Step S2: Target parameter issuance: Surface engineers set the required well inclination increase rate and azimuth adjustment amount for this well section through measurement while drilling and wellbore trajectory design; Step S3, centering and positioning: the control system drives the push-pull sub to start rotating relative to the main shaft, and uses the FOC motor to accurately control its angle; Next, the control system gradually closes the bottom activation valve of the short sub to start the pressure holding process; The mud pressure begins to increase at the front end of the hydraulic chamber, preparing to push the eccentric push pad out; Step S4, extending the eccentric push cushion: when the pressure reaches a controllable threshold, the eccentric push cushion is pushed out in stages using PWM; Step S5, rhythmic pushing control: During the continuous drilling process, the system continuously cycles between "anchoring force application" and "release adjustment" according to a predetermined adaptive rhythmic strategy; Step S6, working mode switching: When the sensor detects an abnormal increase in borehole friction, the system automatically switches to non-contact pushing mode: the eccentric pushing pad is quickly retracted, and the lateral jet channel is opened at the same time, using high-pressure mud jets to clear well wall obstacles and provide temporary lateral force; when the well wall stabilizes, the eccentric pushing pad is resumed; Step S7, stop the tool after drilling: When the target well inclination and azimuth are reached or the deflection task of this section is completed, the ground sends a command to end the guidance mode; the control system gradually reduces the thrust of the eccentric push pad and enters the standby cruise state, waiting for the next guidance command or until drilling.

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