Single-eccentric push-back cushion rotary guiding short section tool and method

Abstract

The invention discloses a rotary guiding short section tool and method for a single eccentric pushing and leaning cushion. The rotary guiding short section tool comprises a pushing and leaning short section, an upper connector, a lower connector, an upper connecting short section, a lower connecting short section and the eccentric pushing and leaning cushion. A radial opening, a slurry channel, a one-way valve and a drain valve are arranged in the pushing short section, the slurry channel is communicated with the radial opening through the one-way valve and the drain valve, and the eccentric pushing cushion is installed in the radial opening of the pushing short section in a sliding mode and forms a hydraulic cavity; an upper main shaft and an upper main shaft motor driving mechanism are arranged in the upper joint; one end of the upper main shaft is connected with the inner wall of the upper connecting short section; a lower main shaft and a lower main shaft motor driving mechanism are arranged in the lower connector, and one end of the lower main shaft is connected with the inner wall of the lower connecting short section. The tool shell and the stratum can be kept approximately static through the FOC reverse rotation principle at the deflecting section, opening and retracting of the eccentric pushing and leaning cushion are achieved through pressure building and control of the one-way valve set, and therefore the purpose of stable and accurate deflecting is achieved.

Description

Technical Field

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

[0002] A friction and wear testing machine is an instrument for testing the friction and wear properties of materials and lubricants under given conditions. Friction and wear testing machines can be divided into various types according to the motion form, such as reciprocating friction and wear testing machines, fretting wear testing machines, etc. The research on its tangential stiffness has been widely concerned.

[0003] Up to now, domestic and foreign scholars' research on fretting wear has focused on the influence of displacement amplitude, load, and frequency on fretting wear behavior. There is little research on the influence of system stiffness on the results of fretting wear tests. The testing methods for the system stiffness of friction and wear testing machines are still not unified, and no relevant technical standard documents have been formed. There is also less research on the system stiffness of friction and wear testing machines at home and abroad. In view of the above situation, it is necessary to conduct innovative research and application on the tangential stiffness testing method, and develop a set of tools and methods applicable to single-eccentric push pad rotary steering sub, which is of great significance to the academic community. Summary of the Invention

[0004] In order to overcome the defects existing in the prior art, the present invention aims to provide a single-eccentric push pad rotary steering sub tool and method.

[0005] The technical solution provided by the present invention to solve the above technical problems is: a single-eccentric push pad rotary steering sub tool, including a push sub, an upper joint, a lower joint, an upper connecting sub, a lower connecting sub, and an eccentric push pad;

[0006] The push sub has a radial opening, a mud channel, a check valve, and a drain valve inside. The mud channel is communicated with the radial opening through the check valve and the drain valve. The eccentric push pad is slidably installed in the radial opening of the push sub and forms a hydraulic cavity. An activation valve is provided at the lower end of the mud channel;

[0007] The two lower ends of the push sub are respectively connected to the upper connecting sub and the lower connecting sub. The upper joint and the lower joint are respectively connected to the upper connecting sub and the lower connecting sub, and rotation occurs between the upper joint and the upper connecting sub, and between the lower joint and the lower connecting sub;

[0008] An upper main shaft and an upper main shaft motor driving mechanism are provided inside the upper joint. One end of the upper main shaft is connected to the inner wall of the upper connecting sub; a lower main shaft and a lower main shaft motor driving mechanism are provided inside the lower joint. One end of the lower main shaft is connected to the inner wall of the lower connecting sub.

[0009] A further technical solution is that rollers are 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 short section.

[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, a groove matching the boss is provided on the inner wall of the radial opening, 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.

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

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

[0017] Step S2, target parameter issuance: the surface engineer sets the required well inclination increase rate and azimuth adjustment amount for this well section by measuring while drilling and designing the wellbore trajectory;

[0018] 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 activation valve at the bottom of the sub to start the pressure holding process; the mud pressure starts to increase at the front end of the hydraulic chamber, preparing to push the pad out;

[0019] Step S4, eccentric push pad extends: 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 Condition Switching: When the sensor detects that the wellbore friction resistance increases abnormally, the system automatically switches to the non-contact pushing mode: quickly retract the pads, and at the same time open the lateral jet channel, use high-pressure mud jets to remove the obstacles on the wellbore wall and provide temporary lateral force; when the wellbore stabilizes, restore the mechanical pad pushing.

[0022] Step S7, Drilling Completion and Tool Stopping: When the target well inclination and azimuth are reached or the build-up task of this section is completed, the ground sends an instruction to end the steering mode; the control system gradually reduces the pad thrust and enters the standby cruising state, waiting for the next steering instruction or until the drill string is pulled out of the well.

[0023] The present invention has the following beneficial effects: The present invention can keep the tool housing approximately stationary with the formation through the FOC reverse rotation principle in the build-up section, and use the pressure holding and one-way valve group control to realize the expansion and retraction of the eccentric pushing pad, so as to achieve the purpose of stable and accurate well deviation. Brief Description of the Drawings

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

[0025] Figure 2 It is a three-dimensional view of the device of the present invention;

[0026] Figure 3 It is a three-dimensional view of the upper sub;

[0027] Figure 4 It is a three-dimensional view of the main shaft;

[0028] Figure 5 It is a three-dimensional view of the activation valve;

[0029] Figure 6 It is a sectional view of the lower connecting nipple;

[0030] Figure 7 It is a sectional view of the lower sub;

[0031] Figure 8 It is a sectional view of the pushing short section;

[0032] Figure 9 It is a three-dimensional view of the eccentric pushing pad. Detailed Embodiment

[0033] Next, the technical solutions of the present invention will be described clearly and completely in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0034] As Figures 1-9As shown in the figure, a single-eccentric push pad rotary steering sub tool of the present invention includes a push sub 1, an upper sub 2, a lower sub 3, an upper connecting sub 4, a lower connecting sub 5, and an eccentric push pad 6;

[0035] The push sub 6 has a radial opening, a mud channel 7, a check valve 8, and a drain valve 9. The mud channel 7 is communicated with the radial opening through the check valve 8 and the drain valve 9. The eccentric push pad 6 is slidably installed in the radial opening of the push sub 1 and forms a hydraulic chamber. The mud channel 7 injects liquid into the hydraulic chamber through the check valve 8, and the hydraulic chamber discharges the liquid into the mud channel 7 through the drain valve 9. An activation valve 10 is provided at the lower end of the mud channel 7;

[0036] The two lower ends of the push sub 1 are respectively connected to the upper connecting sub 4 and the lower connecting sub 5. The upper sub 2 and the lower sub 3 are respectively connected to the upper connecting sub 4 and the lower connecting sub 5, and reverse rotation occurs between the upper sub 2 and the upper connecting sub 4, and between the lower sub 3 and the lower connecting sub 5;

[0037] An upper main shaft 11 and an upper main shaft motor driving mechanism are provided in the upper sub 2. One end of the upper main shaft 11 is connected to the inner wall of the upper connecting sub 4. A lower main shaft 12 and a lower main shaft motor driving mechanism are provided in the lower sub 3. One end of the lower main shaft 12 is connected to the inner wall of the lower connecting sub.

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

[0039] The main shaft is located inside the short sub 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 on the side wall of the short sub housing, and only one piece is provided. Its outer surface can adopt rollers or low-friction materials to reduce wear when contacting the well wall and improve the pushing efficiency;

[0041] The bottom of the radial opening is communicated with the inner cavity of the eccentric push pad 6, which is used to push or retract the push pad by means of the pressure buildup principle;

[0042] The control system therein includes the following sub-modules: Attitude measurement module: Integrating gyroscopes, accelerometers, azimuth sensors and encoders, it is used to collect downhole attitude, well inclination and azimuth data in real time; Dual-group FOC control module: Based on attitude data adjustment, it realizes the same-speed and different-direction (reverse) rotation of the short sub housing and the internal main shaft; Motor: Driving the rotation of the housing and the main shaft, through cooperation with a transmission mechanism (such as a gear or belt drive), closed-loop regulation is realized;

[0043] Activation valve 10: It is arranged at the lower end of the short sub housing and is used to close the mud flow channel during well deviation to generate pressure buildup;

[0044] Check valve 8: Automatically opens when the mud pressure reaches the set value and introduces the mud into the hydraulic chamber;

[0045] Discharge valve 9: Used to discharge the mud in the hydraulic chamber when recovery is needed, realizing the automatic retraction of the push pad.

[0046] In this embodiment, the preferred implementation is that: a convex platform is provided on the outer wall of the lower end of the eccentric push pad, a groove matching the convex platform is provided on the inner wall of the radial opening, a spring is sleeved on the eccentric push pad, the lower end of the spring presses on the convex platform, and the upper end abuts against the upper top surface of the groove.

[0047] A single-eccentric push pad rotary steering method of the present invention utilizes intelligent materials to optimize the support characteristics of the pad, adopts an adaptive rhythm control algorithm to dynamically adjust the pushing period, 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 under special circumstances.

[0048] The whole set of methods can form a complete supporting solution of "device + method" with the original short joint tool, and has significant application advantages in directional drilling of deep wells and horizontal wells.

[0049] 1. Principle of intelligent material regulation: In this method, intelligent materials are introduced into the hydraulic actuator unit of the eccentric push pad to enhance the control accuracy and response ability.

[0050] Magnetorheological fluid (MR fluid) is used as the working medium in the hydraulic chamber of the eccentric push pad, and an electromagnetic coil controller surrounding the chamber is equipped. When the control system applies magnetic fields of different intensities, the viscosity of the MR fluid will change rapidly, thereby adjusting the equivalent stiffness and damping of the hydraulic chamber in real time. When rigid pushing is required, the magnetic field is increased to make the liquid thicken rapidly, locking the position of the pad to form a "semi-active support" similar to that; when buffering or adjustment is needed, the magnetic field is weakened to make the liquid thinner, allowing the pad to produce a slight displacement relative to the wellbore 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 regulated, ensuring both sufficient steering force and avoiding impact loads caused by excessive rigidity.

[0051] This principle is similar to the application of the magnetorheological shock absorption suspension technology of automobiles on drill tools, realizing the adaptive adjustment of the support characteristics of the pad. In addition, intelligent materials can also be used on the surface of the pad, such as applying shape memory alloy inserts to make the pad change its surface morphology or friction coefficient at different temperatures, so as to automatically improve wear resistance or change the contact stiffness in high-temperature well sections. These intelligent material measures do not change the macroscopic structure of the original pad and hydraulic chamber, but only upgrade the materials and media, thereby realizing performance improvement on the premise of ensuring the structure remains unchanged.

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

[0053] This method introduces a strategy of periodic alternating pushing - releasing: within a build - up cycle, the eccentric pad actively presses against the wellbore to provide lateral force during a specific time period ("anchoring" phase), and slightly reduces the thrust or retracts locally during another time period ("releasing" phase). The anchoring phase ensures bit orientation correction and increased well inclination, while the releasing phase allows the downhole tool to get a short "break" to relieve the static friction and wear caused by continuous pressing. This pushing rhythm is not fixed, but is adaptively adjusted by the control system according to the actual situation: for example, when the sensor detects that the wellbore trajectory reaches the expected curvature and the friction force increases rapidly, the release time can be extended to reduce the friction resistance; conversely, when greater build - up force is needed, the release phase can be shortened, the anchoring time can be lengthened, or the thrust can be increased. The core of adaptive rhythm control is to avoid long - term continuous sliding friction, cycle - convert the contact state between static friction and dynamic friction, and disperse the originally possible accumulated high friction resistance, thereby reducing the resistance and sticking risk. This is somewhat inspired by the peristalsis of earthworms / moles in bionics: when an earthworm moves forward in the soil, it alternately expands and anchors and contracts and slides with the front and rear parts of its body rhythmically to overcome friction and move forward. This tool reduces the "stick - slip" effect during rotary build - up by alternately pushing against and yielding with the pad. This rhythm control can also relieve the impact caused by uneven wellbore or lithology changes, protect the tool and improve the build - up stability.

[0054] 3. Bionic-inspired Alternating Anchoring Principle: To further optimize the steering effect, this method is inspired by the natural digging motion in terms of strategy and adopts the working principle of alternating anchoring and adjustment. Similar to a mole using its claws to brace against the hole wall to stabilize its body while adjusting the digging direction, this steering method utilizes eccentric pads as "bionic anchor points": When the pads are in the anchoring stage, it is equivalent to the tool obtaining a fulcrum on the wellbore wall, and the short section housing utilizes this fulcrum to resist the drill string torque and fix the attitude; subsequently, in the release stage, the control system allows the short section housing to rotate slightly or adjust its position relative to the formation (the amplitude is only within a few degrees range and the overall tool face orientation is kept from deviating from the target azimuth). This is like a creature stabilizing a part of its body first and then twisting its "waist" to change direction when turning underground. Specifically, the FOC motor provides reverse torque to keep the housing stationary during the anchoring stage, and reduces the torque during the release stage to allow the housing to fine-tune with the drill string direction, and then quickly reverses the torque again to stabilize the housing. Since the eccentric pads continuously contact the wellbore wall, this fine-tuning does not cause the tool to completely lose stability, but allows slight slippage to adjust the anchoring position. This bionic alternating anchoring method ensures that each time the pads reapply the lateral force, they can act on a new part of the wellbore wall in the most effective posture, avoiding local extrusion or wear caused by pressing on the same point for a long time. In addition, multiple cycles of fine-tuning also make the build-up process smoother and prevent local non-circularity of the wellbore trajectory or tool jamming caused by single-point anchoring for too long. During this process, the short section housing, the main shaft, the motor, and the eccentric pads cooperate closely: the main shaft drives the drill bit to continuously rotate and cut, the short section housing is anchored by the pads to maintain orientation, the motor temporarily unloads or loads as needed to cooperate with the pad displacement, and then quickly stabilizes.

[0055] 4. Multi-dimensional Parameter Fusion Control Principle: To achieve the precise execution of the above-mentioned adaptive rhythm and bionic alternating anchoring, this method relies on a powerful multi-dimensional parameter fusion control system. The control system collects multi-source sensor data, including but not limited to: the real-time well inclination angle and azimuth angle provided by the attitude measurement unit (gyroscope / accelerometer), the contact load feedback from the pad hydraulic pressure and displacement sensors, the formation property feedback at the drill bit (such as the formation hardness or gamma value measured while drilling), the drill string mechanical parameters (such as downhole torque, WOB weight index, vibration acceleration), etc. By fusing these data, the system can comprehensively perceive the current drilling state. For example, if the sensor fusion result shows that the well inclination growth rate is lower than the target and the formation is soft, the control algorithm will increase the pushing force or extend the anchoring phase; if severe vibration and torque fluctuations are detected, it is judged that the friction is too large or a hard formation is encountered, and the algorithm automatically increases the release frequency to reduce the impact. In addition, this fusion control also introduces adaptive algorithms (such as fuzzy control or reinforcement learning models) to enable the system to continuously optimize parameters based on historical data. That is to say, the tool "learns" while working during drilling: continuously correcting the relationship model between the pushing force and the trajectory change to achieve more and more precise control. This closed-loop control logic of multi-dimensional parameter fusion ensures the reliability and real-time adaptability of the steering method - regardless of how the downhole conditions change, the system can comprehensively judge and adjust the strategy and always move forward along the predetermined trajectory. At the same time, the control system also has built-in redundancy and fault tolerance mechanisms: when the data of a certain sensor is abnormal, it can rely on the information of other dimensions to maintain the stability of the control decision and prevent out-of-control situations.

[0056] 5. Energy-saving reaction mechanism principle: Given the limited downhole power supply, this method particularly emphasizes the efficient utilization of energy. The energy-saving reaction mechanism is used to reduce the motor load and hydraulic energy consumption. The principle is to make full use of the passive reaction force to replace the active energy consumption during the generation and maintenance of the guiding force. When the eccentric pad is anchored against the wellbore wall, the friction force between the pad and the wellbore wall will naturally generate a counter-torque, offsetting part of the rotational torque transmitted from the main drill string to the short joint housing. This method cleverly utilizes this point: during the anchoring stage of the pad, the control system reduces the output of the FOC motor, and the friction force of the pad itself undertakes the main role of stabilizing the housing pressure. Only when it is detected that the housing starts to have a sliding tendency relative to the wellbore wall (indicating that the friction force is not sufficient to completely balance the torque), the motor promptly compensates for the torque to stabilize it. In this way, the torque required for directional control is mainly provided passively by the wellbore reaction force for most of the time, and the motor is in a low-power standby state, only intervening briefly for correction when necessary. This is similar to reasonably using gravity when riding a pedal bicycle downhill: pedaling hard when going uphill (motor adding force), and coasting when on flat ground or downhill (using the reaction force). At the same time, during the release stage, when the pad slightly moves away from the wellbore wall, there will be a small following rotation of the housing relative to the drill string. At this time, the motor can even switch to the regenerative braking mode, converting the kinetic energy of the short-term reverse sliding into electrical energy and recovering it to the energy storage unit (such as using the principle of motor regenerative braking). In addition, the process of driving the pad to extend by hydraulic "pressure holding" has also been optimized: in the traditional method, it is necessary to close the activation valve to accumulate enough mud pressure and then open the one-way valve to push the pad. On this basis, this solution combines MR fluid technology to precisely control the opening and closing rhythm of the valve to avoid overpressure waste. For example, when the pad approaches the target extension position, the damping is increased by the magnetorheological fluid to reduce the extension speed, and the one-way valve is immediately closed to lock the pressure after reaching the position, without continuous high-pressure liquid supply, thus saving the pump power consumption. In summary, the energy-saving reaction mechanism greatly improves the energy utilization efficiency of the system through the utilization of passive forces and energy recovery, enabling the guiding tool to maintain sufficient power supply and controllable temperature rise during long-term operation.

[0057] 6. Non-contact pushing principle: For some special working conditions (such as extremely broken and unstable wellbore walls, and the need to avoid direct contact to prevent induced well leakage, etc.), this method reserves an auxiliary guiding mode of non-contact pushing. The non-contact pushing relies on directional hydraulic jets to apply lateral forces. The principle is to form a high-speed mud jet near the lateral opening where the eccentric pad is located, and use the hydrodynamic pressure difference to "blow and squeeze" the tool in the opposite direction to change the direction of the drill bit.

[0058] In terms of specific implementation, the original hydraulic cavity and pad structure can be utilized. When the non-contact mode is required, the control system keeps the eccentric pad retracted or slightly suspended about several millimeters away from the wellbore, and at the same time opens a special bypass channel to allow some drilling fluid to flow through small nozzles or orifices at the opening of the pad (this modification does not change the main structure, only micro-holes are machined on the pad or the housing). Due to the large mud pumping flow rate, once it leads to the side orifices, a strong lateral jet is formed and rushes towards the wellbore. According to Bernoulli's principle, a high-pressure area is formed on the pad side by the jet, while a relatively low pressure is formed on the opposite side of the tool, thus generating a net lateral force that pushes the tool towards the low-pressure side. By controlling the opening and closing and the flow rate ratio of the side jets, the attitude of the drill string can be adjusted without directly contacting the wellbore. It should be noted that the non-contact pushing mode is generally only used as an auxiliary. During conventional well deviation, mechanical pad pressing is still the main method, and the jet is the auxiliary; while when the wellbore is extremely sensitive or the tool needs to be loosened temporarily, it is temporarily switched to full jet guidance. This method realizes a "water pad" type of pushing effect - similar to adding a layer of high-speed fluid lubrication between the pad and the wellbore, changing the pushing from frictional contact to hydrodynamic action. Its advantage lies in zero friction and wear, and it can avoid mechanical disturbance to the wellbore. However, considering the limited jet thrust, this mode is combined with mechanical pushing to balance accurate well deviation and wellbore protection.

[0059] To sum up, the working principle of this guiding method is an extension and enhancement of the guiding mechanism of the original single-eccentric pad RSS tool: continuing to utilize the essential mechanism of directly applying force by a single pad to change the bit direction, but making the application method of this force more controllable, flexible, and energy-saving through intelligent materials and advanced control, and realizing non-contact guidance by means of fluid mechanics under specific conditions. During the whole process, the original structural relationship is maintained among the sub-section housing, the main shaft, the eccentric pad, the hydraulic cavity, and the control system, but the interaction method is more intelligent: the main shaft still transmits the drilling torque, the sub-section housing still undertakes the guiding deflection function, the eccentric pad is still the acting point of the lateral force, the hydraulic cavity still provides the power source for the pad, and the control system becomes a smarter brain to coordinate the actions of all parts. It is precisely this idea of keeping the structure unchanged and innovating the method that enables 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 to the target well section and ready to start directional deviation, the surface and downhole control systems first complete the initialization handshake. The sub control system self-checks the status of each sensor and actuator, confirms that the eccentric pad is in the retracted position, the hydraulic chamber pressure is normal, the MR fluid magneto-control system is working properly, the motor energy storage is sufficient, etc. At the same time, the working conditions of the current well section (such as vertical well section, deviation section, holding angle section, etc.) are judged according to the measurement data. If it is judged that the well section needs to be deviated, the system will switch to the "guidance active mode"; if it is still in the vertical well section, the "vertical well passing mode" will be maintained. In this mode, the sub 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 deviation section is entered, so the system enters the guidance mode and waits.

[0062] Step 2. Target Parameter Issuance: The surface engineer sets the required hole angle increase rate and azimuth adjustment amount for this well section through measurement while drilling and designing the wellbore trajectory. This instruction is sent to the downhole sub control system through mud pulse telemetry or wired transmission. The control system reads the target parameters, such as a required build rate of 3° / 30m and a 15° right turn in azimuth, etc., and then combines the currently measured hole angle / azimuth to calculate the direction and approximate amplitude of the lateral force to be applied. At this time, the control system determines 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 requires a medium to strong pushing force 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 and precisely controls its angle using the FOC motor. Referenced by the gyro / magnetic azimuth instrument, the housing is rotated to the position where the eccentric pad points to the predetermined tool face direction. Since deviation pushing has not started yet and the drill string is generally rotating, the control system will adopt a short-term dynamic centering strategy: that is, while the drill string is rotating continuously, the motor rotates in the reverse direction at a speed slightly higher than the drill string speed to stably align the housing with the target direction. After positioning, the housing remains stationary or rotates slowly within ± a few degrees relative to the formation, thus 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. The 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 the pressure reaches the controllable threshold, the control system does not simply open the one-way valve completely at once as in the traditional method, but uses PWM (pulse width modulation) or proportional valve control technology to push out the eccentric pad in stages. First, slightly open the one-way valve to allow a small amount of high-pressure mud to enter the hydraulic chamber, so that the pad slowly extends to contact the well wall. At this stage, the MR liquid is in a low-viscosity state to provide buffering, and the pad touches the well wall at a steady speed instead of violently hitting it. The sensor detects the initial contact of the pad (signal of sudden pressure increase and displacement stop), and the control system temporarily stops the slurry feeding and waits for the shell to stabilize. Then enter the main push stage: the controller opens the valve again to increase pressure and pushes the pad further out to the required push force or displacement. During the process, the MR liquid magnetic field gradually increases to increase damping and avoid oscillation. When it is detected that the preset thrust is reached (judged by the hydraulic pressure sensor) or the pad stroke reaches the upper limit, the control system closes the one-way valve to lock the pressure and fix the pad in the current extension position. At this time, the eccentric pad has firmly pressed against the well wall and entered the anchoring state. The drill bit deviates to the required direction to start cutting the formation and achieve deflection.

[0065] Step 5, rhythmic push control: During the continuous drilling process, the system continuously cycles between "anchor force" and "release adjustment" according to the predetermined adaptive rhythm strategy. Specifically, for example, a cycle is performed every 360° rotation (or according to the rhythm frequency required) - during the approximately 270° angle, the eccentric pad maintains anchor push (the FOC motor continuously provides counter torque to keep the shell stationary), and then enters release adjustment during the approximately 90° angle (the motor torque is reduced to allow the shell to slide slightly, and the MR liquid reduces the viscosity to allow the pad to slightly buffer 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 it is found that the slope rate is not enough, the release time may be shortened or the retraction amplitude may be reduced to increase the average lateral force; on the contrary, if the friction resistance increases sharply or micro-oscillation occurs, the release time or amplitude is increased to restore the system to balance. In the whole cycle, formation feedback parameters (such as trajectory changes measured while drilling) are also taken into consideration. After several cycles, the control system evaluates the actual well inclination and azimuth deviation, and fine-tunes the target tool face direction or thrust size when necessary, and enters the next optimization cycle. Through such closed-loop regular control, the drilling trajectory is constantly pulled back to the planned curve.

[0066] Step 6: Switching working conditions: If a special situation is encountered during drilling, such as the well wall collapse causing the pad to sink into the soft mud and lose its support force, or the sensor detects an abnormal increase in borehole friction (which may indicate adhesion), the control system will trigger the corresponding response process. For example, when the pad supports the collapsed mud cake but does not produce the expected deflection effect, the system can automatically try to switch to the non-contact push mode: quickly retract the pad (open the discharge valve to release pressure, and the pad retracts under the action of the spring), and at the same time open the lateral jet channel to use high-pressure mud jets to clear the well wall obstacles and provide temporary lateral force. Once the well wall stabilizes, the mechanical pad push is restored. For another example, when a stick-slip trend is detected, the system will increase the frequency of pad release or even release it completely for a short time, allowing the drill string to rotate a few times to freely restore power transmission, and then re-anchor the guide. The entire process is completed by the control system to switch functions autonomously without human intervention, but the ground will receive status updates. In addition, if the well section is converted (for example, from the deflection section to the stable deflection section or even the horizontal section), the system will smoothly adjust the strategy according to the pre-settings: reduce the deflection force, or re-lock the housing / spindle to rotate synchronously to avoid unnecessary lateral forces. These operating procedures ensure that the tool transitions smoothly and works uninterruptedly under various working 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 guidance mode. The control system gradually reduces the thrust of the pad: first enter the release stage to release the anchor, then open the discharge valve to slowly release the pressure, let the mud in the hydraulic chamber 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 casing 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 guidance instruction or until drilling.

[0068] Short section housing: The short section housing remains the carrier of the guiding force, which transmits the lateral force to the wellbore through the eccentric push pad. However, different from the traditional continuous static state, under the adaptive rhythm control, the housing rotates slightly and re-anchors regularly. The attitude sensors (magnetic azimuth, accelerometer) integrated on the housing feed back the azimuth angle and motion state of the housing to the control system in real time, enabling the control system to accurately grasp whether the housing maintains the target orientation or slips. The bearing assembly between the housing and the internal main shaft is designed to withstand alternating torque and periodic micro-vibrations, and is supplemented with a damping structure (such as adding particles to the lubricating oil in the bearing to achieve damping) when necessary to prevent high-frequency resonance. The eccentric push pad and possible jet micropores are installed at the openings on the housing surface, and its structure needs to ensure the strength is not affected while increasing the jet channels. Overall, the short section housing is both the execution end (the action component that embodies the control instruction as a physical thrust) and the sensing hub (its motion state affects the control decision) in the cooperation mechanism.

[0069] Internal main shaft: The main shaft still transmits the rotation of the drill string to the drill bit and is the power channel for drilling. Since the short section housing may rotate in the opposite direction or vibrate slightly relative to the main shaft, the main shaft uses a universal joint or a flexible connection to ensure that these relative motions do not affect the drill bit rotation speed. Sensors for measuring the weight on bit and torque (or deduced from the change in motor current) are usually installed on the main shaft, and this data is provided to the control system to judge the anchoring effect of the pads: for example, when the pads are effectively anchored, the torque fluctuation of the main shaft decreases and the effective action of the weight on bit increases, and conversely, if the pads slip, the torque of the main shaft may drop suddenly, etc. The relative rotation angle between the main shaft and the housing is monitored by an encoder. Once the housing deviates from relative rest, the encoder signal cooperates with the gyroscope data to feedback this, enabling the motor to adjust the torque to rebalance. This forms a negative feedback control pair between the main shaft and the housing: the main shaft drives the drill bit forward, and the housing deflects to correct the direction. The two dynamically interact but reach balance under the coordination of the control system, just like the pedals (main shaft) and the handlebars (housing) need to cooperate to maintain the forward direction when riding a bicycle.

[0070] Eccentric Pushing Cushion: The eccentric cushion block is the "finger" directly affected by the entire guiding force. In the new method, its structure remains unchanged (single-eccentric telescopic cushion block), but its working mode is more diversified. First, the hydraulic cavity on the inner surface of the cushion block is filled with magnetorheological fluid, which provides variable stiffness / damping characteristics compared with traditional hydraulic oil and is regulated in real time by the control system. The cushion block is connected to the cavity through a hydraulic piston, and displacement and pressure sensors are added to the piston to accurately measure the position and force of the cushion block extending. Anti-friction rollers or low-friction materials can still be installed on the surface of the cushion block to reduce contact friction; at the same time, due to the introduction of fluid lubrication and periodic release in the new method, the surface wear of the cushion block will be further reduced. Several tiny nozzles on the cushion block (which can be set in combination with the roller position) spray mud to form a hydraulic side push when needed. This requires the internal design of the cushion block to guide a part of the liquid flow to the nozzles - by opening bypass small holes in the cushion block piston and connecting high-pressure mud to the front spray holes of the cushion block when the piston is aligned at a specific position. Usually, when the piston does not reach this position, the spray holes are not under pressure and do not affect the normal hydraulic function. The spring return mechanism of the eccentric cushion block is also optimized in the new scheme: a shape memory alloy spring can be used to replace the ordinary spring, so that it can still maintain sufficient return elastic force when the temperature rises (motor heating or environmental high temperature) and will not creep and fail. During the operation process, the cushion block, the outer shell, and the hydraulic cavity together form a pushing and relying actuator, generating thrust or retracting in response to the instructions of the control system. It provides rigid support during anchoring, gives smooth yielding during release, and acts as a hydraulic nozzle seat in the jet flow mode, with diverse and reliable functions.

[0071] Hydraulic Cavity and Valve Group: The hydraulic cavity and its valve group are the power units for driving the telescopic movement of the cushion block, and its hardware structure maintains the original design, including activation valves, check valves, and discharge valve passages. In the new method, the control of the valve group is more refined: the activation valve is controlled by pulses and can be partially opened and closed to adjust the pressure buildup rate; the check valve adds an electric control auxiliary opening and closing (parallel electromagnetic control on the basis of traditional hydraulic self-adaptation to achieve PWM flow regulation); the discharge valve adds an adjustable throttle valve to control the pressure relief speed and prevent the cushion block from suddenly retracting and impacting. The magnetorheological fluid in the hydraulic cavity requires a magnetic field generating device - a high-temperature resistant coil can be wound around the outer wall of the cavity and powered by the control system to control the strength of the magnetic field. The entire hydraulic drive module plays the role of "muscle and tendon" in the coordination mechanism: generating corresponding mechanical displacements and forces according to the "nerve signals" (electric control valve instructions, coil current, etc.) sent by the control system. It should be emphasized that this module maintains its inherent reliability through a simplified multi-channel design, and the introduction of intelligent materials and electric control does not significantly increase leakage points or failure points - because the main hydraulic path is still single, and the electric control valve still maintains the function of the original hydraulic valve in case of failure and will not get out of control.

[0072] FOC Motor and Control System: The motor and control system are the brain and center of the new method. The FOC motor provides the power for the short section housing to rotate in the opposite direction of the spindle, and its control accuracy directly determines the attitude stability of the housing. The new method enables the motor to apply precise torque to counteract the drill string torque during anchoring through advanced control algorithms (such as feedforward + feedback composite control), and to quickly respond to achieve tracking control during release fine-tuning. The motor controller and sensor fusion algorithm are highly integrated, and can adjust the motor current according to gyro and encoder data in a millisecond cycle to control the movement of the housing in a synchronous or asynchronous manner. In addition, the control system includes an embedded industrial computer that runs a real-time operating system and processes all sensor data and actuator commands. It has multiple built-in control modes: state machines such as normal guidance, adaptive rhythm, abnormal working conditions, jet mode, and vertical well mode, and switches the logic once the trigger condition is received. The control system also communicates with the ground, receiving instructions and uploading data. In the cooperation mechanism, the control system is undoubtedly the decision-making center, but it also forms a cycle of information and energy with each downhole component: the sensor feeds back the component state to the control system, the control system calculates and outputs to the motor and valve group to affect the component movement, and the component movement changes the drilling state and is captured by the sensor... Such continuous cycling constitutes a closed-loop cooperation system. It is worth mentioning that the software algorithm of the control system itself is also a key "component", which ensures the reliability and optimization degree of hardware cooperation through advanced software fault tolerance and adaptability.

[0073] Overall, the characteristics of the cooperation mechanism of each component under this guidance method are: each performs its own duties, dynamically coupled, and intelligently coordinated. The short section housing / spindle provides the mechanical framework, the pad / hydraulic actuator outputs the lateral force, and the motor / controller coordinates the direction and magnitude of the force in real time. Compared with the traditional RSS, the single eccentric pad structure simplifies the redundant components and makes the cooperation relationship more direct; on this basis, the control "brain" is given intelligence, making the whole system cooperate tacitly like a biological function.

[0074] To sum up, the present invention integrates intelligent material technology, advanced control algorithms and bionic mechanics concepts, significantly improving the accuracy, efficiency and reliability of directional drilling. It shows particular advantages in harsh environments such as deep wells and ultra-long horizontal wells, and can help oil and gas development reach the target formation more safely and efficiently. This technical solution simplifies complexity with simplicity and wins with wisdom, giving full play to the power of method innovation, elevating the existing rotary steerable tools to a new level, and bringing a revolutionary application prospect to the field of drilling orientation.

[0075] As mentioned above, it is not any form of limitation to the present invention. Although the present invention has been disclosed by the above embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some changes or modifications to equivalent embodiments of equivalent changes by using the disclosed technical content within the scope of the technical solution of the present invention. However, any simple modification, equivalent change and modification 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 shall fall 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 short section, an upper joint, a lower joint, an upper connecting short section, a lower connecting short section, 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-pull 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 two ends of the push-pull 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; An upper spindle and an upper spindle motor drive mechanism are arranged 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 arranged in the lower joint, and one end of the lower spindle is connected to the inner wall of the lower connecting short section.

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: The push-pull short section is internally provided with a posture measurement module, a dual-group FOC control module and a power supply module.

5. A single eccentric push pad rotary guide short section tool according to claim 4, 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 short section.

6. A single eccentric push pad rotary guide short section tool according to claim 4, characterized in 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 them back to the dual-group FOC control module in real time.

7. A single eccentric push pad rotary guide short section tool according to claim 1, characterized in that: 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 the eccentric push pad is sleeved with a spring, 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.

8. A method for rotating and guiding a single eccentric push pad, 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 7 for guiding, and the specific steps are as follows: Step S1, initialization and pattern recognition: When the drilling tool is lowered to the target well section and is ready to start directional deflection, the ground and downhole control systems first complete the initialization handshake; Step S2, target parameter issuance: the surface engineer sets the required well inclination increase rate and azimuth adjustment amount for this well section by measuring while drilling and designing the wellbore trajectory; 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 section to start the pressure holding process; The mud pressure begins to increase at the front end of the hydraulic chamber, preparing to push the pad out; Step S4, eccentric push pad extends: when the pressure reaches a controllable threshold, PWM is used to push the eccentric pad out in stages; Step S5, rhythmic pushing control: during the continuous drilling process, the system continuously cycles between "anchoring force" and "release adjustment" according to a predetermined adaptive rhythmic strategy; Step S6, working mode switching: the sensor detects that the borehole friction resistance increases abnormally, and the system automatically switches to the non-contact pushing mode: the pad is quickly retracted, and the lateral jet channel is opened at the same time, and the high-pressure mud jet is used to clear the well wall obstacles and provide temporary lateral force; when the well wall is stabilized, the mechanical pad pushing 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 pad thrust, enters the standby cruise state, and waits for the next guidance command or until drilling starts.

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