An easy build angle mixing type rotary steerable drilling system

Abstract

The application discloses a mixed type rotary steering drilling system with easy build-up, which comprises a front bearing body, a drilling pressure torque deflection transmission short section and a deflection control system, and further comprises a plurality of serially connected universal drilling pressure torque transmission short sections arranged behind the drilling pressure torque deflection transmission short section; the drilling pressure torque deflection transmission short section and the universal drilling pressure torque transmission short sections all comprise a universal joint, a drill bit is fixedly connected to the front end of the front bearing body, the output end of the universal joint is fixedly connected to the rear end of the front bearing body, and a front pushing and abutting assembly is arranged on the circumferential surface of the front bearing body; the deflection control system controls the drilling direction by controlling the radial pushing and abutting piece of the front pushing and abutting assembly to push and abut the well wall along the radial direction of the front bearing body, so that the front bearing body generates a deflection angle relative to the input shaft of the universal joint with the center point position of the universal joint as the center, and the build-up rate is improved; and the directional drilling can be realized through a high-curvature wellbore since the deflection angle is generated by overcoming a small force for the deflection of the universal joint.

Description

Technical Field

[0001] The present invention relates to the technical field of oil exploitation and drilling, in particular to an easy-to-deflect hybrid rotary steering drilling system. Background Art

[0002] Rotary steerable drilling technology is currently the most representative and advanced drilling technology in the world. Based on the operating mode of the downhole tool system, rotary steerable systems (RSS) are divided into four types: static bias push, dynamic bias push, static bias pointing, and dynamic bias pointing. Push and pointing are two types of existing steerable drilling systems based on different drill bit guidance principles. The push-bit type uses a biasing mechanism (a piston pushes against the wellbore wall) to bias the drill bit near the drill bit, directly providing lateral force. The pointing-bit type uses a biasing mechanism (an eccentric ring or eccentric disc) to directly or indirectly deflect the drill bit from the wellbore axis, pointing it in the steerable direction. The biasing mechanism operates in two modes: static bias and dynamic bias. Static bias means that during drilling, the biasing mechanism does not rotate with the drill string, providing a fixed lateral force in a specific direction. Dynamic bias means that the biasing mechanism rotates with the drill string during drilling, relying on a control system to generate a directional, periodic lateral force at a specific location.

[0003] In the article "Study on the Deflection Performance of Push-to-Push and Point-to-Point Rotary Steering Tools" published by Zheng Deshuai, Gao Deli, Feng Jiangpeng and Zhang Hongbao, Petroleum Drilling Technology, 2011, 33(6): 10-13, the advantages and disadvantages of the deflection performance of various rotary steering tools were evaluated. Specifically, the push-to-pull rotary steering system requires the driving piston of its bias mechanism to use a very large lateral force to push the drill bit away from the original wellbore to achieve slow steering, that is, the drill bit rotation angle (well inclination angle) that can be achieved is small, and the deflection function cannot be completed efficiently, and the deflection rate is low. In addition, during the steering process, a very large lateral force needs to be applied to the drill bit, making it difficult to control the wellbore direction. Therefore, the quality of the wellbore trajectory formed is poor, that is, the deflection stability is poor. Specifically, in addition to the above-mentioned disadvantages, the static offset push-to-pull drill bit also has an extremely low deflection rate and cannot drill a wellbore with a high deflection rate.

[0004] Furthermore, long-term practical experience has shown that the pusher components of a dynamic offset push-pull drill bit system rotate with the drill bit and, under push pressures ranging from hundreds of kilograms to several tons, generate significant friction with the rock, resulting in severe wear and a short service life. Drilling operations often fail due to pusher component failure. Therefore, a guide structure that can facilitate deflection creation is urgently needed to address these field challenges.

[0005] The static offset directional rotary steering system controls the combination of eccentric rings above the drill bit to offset the drill bit in a fixed direction. Although this system can produce a stable inclination rate, the underside of the drill bit lacks reliable variable diameter support that can adapt to the wellbore shape. During guidance, the eccentric rings, center drive shaft and other mechanisms and components are subjected to high-intensity alternating stress and are prone to fatigue damage. In addition, its control unit must be installed on a stable platform. The dynamic offset directional rotary steering system requires an independent reversing motor to maintain its deflection, which requires a large amount of motor power. In addition, other forms of dynamic offset rotary steering also have problems such as difficulty in controlling the wellbore trajectory. Summary of the Invention

[0006] The purpose of the present invention is to provide an easy-to-inclin hybrid rotary steering drilling system, which generates a pushing deflection force by controlling the radial pushing member of the front pushing assembly to push the radial well wall of the front bearing body, so that the front bearing body generates a deflection angle relative to the input shaft of the universal joint with the center point position of the drilling pressure torque deflection transmission short section as the center and the contact point between the stabilizer and the well wall as the fulcrum, thereby completing the hybrid rotary steering function. The system only needs to generate a very small pushing deflection force through the front pushing assembly to rotate the universal joint and realize the rotary steering function of the drill bit, and uses the contact point between the stabilizer and the well wall as the fulcrum, which increases the reliability and inclinating stability of the system.

[0007] The technical solutions of the present invention are as follows:

[0008] A hybrid rotary steerable drilling system that is easy to deflect, includes a front bearing body, a drilling pressure torque deflection transmission short section and a deflection control system, the drilling pressure torque deflection transmission short section includes a universal joint, the front end of the front bearing body is fixedly connected to a drill bit, and the rear end is fixedly connected to the output end of the universal joint, and the circumferential surface of the front bearing body is provided with a front pushing assembly; the deflection control system controls the radial pushing member of the front pushing assembly to push against the well wall along the radial direction of the front bearing body, so that the front bearing body generates a deflection angle relative to the input end of the universal joint with the center point position of the universal joint as the center.

[0009] Preferably, the easy-to-deflect hybrid rotary steerable drilling system also includes a stabilizer arranged behind the front pushing assembly. If the center point of the stabilizer is located behind the center point of the universal joint, the distance between the center point of the stabilizer and the center point of the universal joint is not greater than 3 times the diameter of the drill bit; the deflection control system controls the radial pushing member of the front pushing assembly to push against the well wall along the radial direction of the front bearing body, so that the front bearing body generates a deflection angle relative to the input end axis of the universal joint with the center point of the universal joint as the center and the contact point between the stabilizer and the well wall as the fulcrum.

[0010] Preferably, the front bearing body and the weight-on-bit torque deflection transmission sub are both through-structures, and the through-structures form a main flow channel for the circulation of drilling circulating medium.

[0011] Preferably, the easy-to-deflect hybrid rotary steerable drilling system further comprises an elastic flow tube passing through the hollow structure of the universal joint and connecting the input end and the output end of the universal joint.

[0012] Preferably, the weight-on-bit torque deflection transmission sub is provided with an elastic stabilizing device for preventing the front push assembly from driving the front load-bearing body to rotate about the universal joint. The elastic stabilizing device maintains the coaxiality of the input shaft and output shaft of the universal joint. The input shaft may be a load-bearing drill collar connected to the input end of the universal joint, and the output shaft may be a load-bearing drill collar connected to the output end of the universal joint.

[0013] Preferably, the elastic stabilization device includes an elastic tube that passes through the hollow structure of the universal joint, connecting the input and output ends of the universal joint. This through-structure fully utilizes the space near the universal joint, leaving ample room for the elastic tube to deform, allowing it to withstand greater deformation. The elastic tube provides a damping force that keeps the input and output shafts of the universal joint aligned. This damping force is significantly less than the force required to deflect a conventional flexible joint, and the deflection point is lower, further facilitating the release of tool guidance performance.

[0014] Preferably, the limiting mechanism includes a lever structure and a supporting drill collar shell, a deflection space is generated between the lever structure and the inner wall of the supporting drill collar shell, and the lever structure is in contact with the inner wall of the supporting drill collar shell to withstand the thrust of the rotary guide hydraulic piston and / or the bending moment caused by the vibration downhole and / or the lateral component caused by the drilling pressure.

[0015] Preferably, the elastic stabilization device includes a plurality of elastic shafts centrally symmetrically arranged in a ring within the universal joint supporting drill collar housing, the elastic shafts providing a damping force that causes the input shaft and the output shaft of the universal joint to be in the same straight line; and / or the elastic stabilization device includes a plurality of leaf springs arranged in a deflection space between the lever structure and the supporting drill collar housing.

[0016] Preferably, the WOB torque deflection transmission sub also includes a limit mechanism for limiting the deflection angle within a range of 0° to 5°. When the WOB torque deflection transmission sub is rotated to any angle within the range, the restoring force provided by the elastic stabilization device, which drives the universal joint input and output ends back to a coaxial state, can overcome the radial force component generated at the rated maximum WOB at that angle. The radial force component is approximately the WOB multiplied by sinα, thus maintaining the tendency for the universal joint input and output ends to return to a coaxial state.

[0017] Preferably, the deflection control system includes an electrical actuator for controlling the radial pushing member to radially push the front supporting body against the well wall to generate a deflection force, a posture measurement device and a downhole computing device for measuring the deflection angle of the front supporting body; the downhole computing device includes a computing chip electrically connected to the posture measurement device, the electrical actuator and the power supply device.

[0018] Preferably, the computing chip receives the deflection angle information collected by the attitude measurement device and compares it with the target deflection angle information to calculate the steering direction and steering force, and then controls the electrical actuator to make the front pushing component generate a thrust force opposite to the steering direction on the well wall, and through closed-loop control, the angular size and rotation amplitude of the drilling pressure torque deflection transmission short section are consistent with the preset value.

[0019] Preferably, the attitude measurement equipment includes a deflection sensor for measuring the size and direction of the universal joint angle of the drilling pressure torque deflection transmission short section, and the corresponding deflection angle information includes the rotation direction information and angle size information of the front bearing body relative to the universal joint input shaft measured by the deflection sensor; the target deflection angle information includes the rotation direction information and angle size information of the front bearing body relative to the universal joint input shaft pre-stored in the downhole computing device or transmitted to the downhole computing device through the communication device.

[0020] Preferably, the attitude measurement device includes a first accelerometer and / or a first magnetometer provided on the front carrier body, and the corresponding deflection angle information includes the well inclination angle information and azimuth angle information measured by the accelerometer and magnetometer; the target deflection angle information includes the target well inclination angle information and target azimuth angle information of the front carrier body relative to the universal joint input axis, which are pre-stored in the downhole computing device or transmitted to the downhole computing device through the communication device.

[0021] Preferably, the attitude measurement device includes an accelerometer and / or magnetometer arranged on the front carrying body, and also includes a rear attitude measurement device arranged behind the drilling pressure torque deflection transmission short section, the rear attitude measurement device includes at least a group of rear acceleration sensors, and a group of rear magnetometers, for realizing attitude measurement in an environment with less vibration and magnetic interference; the deflection angle information includes the well inclination angle information and azimuth angle information measured by the first accelerometer and the second magnetometer, and the target deflection angle information includes the target well inclination angle information and target azimuth angle information of the front carrying body relative to the universal joint input shaft, which is pre-stored in the downhole computing device or transmitted to the downhole computing device through the communication device.

[0022] Preferably, the axial distance between the centralizer and the center point of the universal joint is less than or equal to 8 times the maximum diameter of the drill bit; and at least one of the weight-on-bit torque deflection transmission mechanisms is arranged within 20 times the maximum diameter of the drill bit; and / or the average outer diameter of the front bearing body is 50%-100% of the outer diameter of the drill bit.

[0023] Preferably, the front-end push-pull assembly is symmetrically arranged in 2-6 groups around the circumferential surface of the front-end bearing body. The front-end push-pull assembly includes a hydraulic piston and radial push-pull members. The front-end bearing body and the push-pull members rotate synchronously with the drill bit. The multiple groups of push-pull members periodically push against the wellbore wall to generate a combined force acting on the front-end bearing body to guide the direction. The radial push-pull members include ribs or hydraulic piston drive sleeves. The hydraulic piston is powered by the drilling circulating medium in the main flow channel. The electrical actuator controls the diversion device to alternately supply the hydraulic piston with high-pressure drilling fluid in the main flow channel.

[0024] Preferably, the electrical actuator includes an electric motor, an electric rotary valve and a motor driver. The electric rotary valve includes a rotary valve motor end and a rotary valve follower end. The motor driver is arranged in the downhole computing device. According to the control instructions of the downhole computing device, the rotary valve motor end is rotated relative to the rotary valve follower end, so that the rotary valve motor end is diverted through the diversion device to realize the control of the front rib assembly.

[0025] Preferably, the rigid universal joint is a cross-axis universal joint, a ball cage universal joint, a ball fork universal joint or a ball hinge universal joint.

[0026] Preferably, the power supply equipment includes a downhole turbine generator, and the downhole turbine generator is arranged behind the drilling pressure torque deflection transmission short section.

[0027] Preferably, a communication device is further provided behind the weight-on-bit torque transmission deflection sub to enable communication between the downhole computing device and the wellhead equipment.

[0028] Preferably, a first WOB torque deflection transmission subsection and a second WOB torque deflection transmission subsection are sequentially provided behind the front carrying body, the distance between the center points of the universal joints of the first WOB torque deflection transmission subsection and the second WOB torque deflection transmission subsection is less than 3 times the maximum diameter of the drill bit, the centralizer is arranged between the first WOB torque deflection transmission subsection and the second WOB torque deflection transmission subsection, or the centralizer is arranged in front of the first WOB torque deflection transmission subsection; the distance from the centroid of the universal joint in the first WOB torque deflection transmission subsection to the centroid of the drill bit is less than 20 times the maximum diameter of the drill bit; the input shaft of the universal joint in the first WOB torque deflection transmission subsection is fixedly connected to the output shaft of the universal joint of the second WOB torque deflection transmission subsection, the first WOB torque deflection transmission subsection includes a first elastic stabilization device, and the second WOB torque deflection transmission subsection includes a second elastic stabilization device.

[0029] Preferably, the front bearing body includes a guide sleeve and a central shaft that rotates freely within the guide sleeve via radial and axial thrust bearings. The front thrust assembly is disposed on the circumferential surface of the guide sleeve. The front end of the central shaft is fixedly connected to a drill bit, and the rear end is fixedly connected to the output bearing housing of the universal joint. The WOB torque deflection transmission sub also includes a universal joint output bearing housing sleeved on the outside of the universal joint. A gap is defined between the universal joint output bearing housing and the universal joint to form a deflection space within which the universal joint can deflect 0° to 5° relative to the axis of the fixed sleeve. The centralizer is disposed outside the universal joint output shaft bearing housing, and the distance between the centralizer's center point and the universal joint of the first WOB torque deflection transmission sub is less than or equal to 2 meters. The bearing housing in the present invention is a drill collar housing capable of bearing and transmitting WOB torque.

[0030] Preferably, the easy-to-deflect hybrid rotary steerable drilling system further comprises one or more interconnected universal WOD torque transmission subs located behind the WOD torque deflection transmission subs, each of which comprises the universal joint and the limiting mechanism; the WOD torque deflection transmission subs and the WOD torque deflection transmission subs are through-hole structures, and the distance between the universal joint centers of the universal WOD torque transmission subs is less than 10 times the maximum diameter of the drill bit. The distance from the universal joint centroid of the WOD torque deflection transmission sub closest to the drill bit to the drill bit should be less than 15 times the maximum diameter of the drill bit, to ensure that the front bearing body does not scrape against the wellbore wall with high curvature.

[0031] Preferably, the elastic stabilizing device passes through the weight-on-bit torque deflection transmission sub and the weight-on-bit torque deflection transmission sub;

[0032] Preferably, the sum of the length of the universal weight-on-bit torque transmission sub array formed by the plurality of interconnected universal weight-on-bit torque transmission subs and the length of the front bearing body and the drill bit is greater than the length of the branch well section.

[0033] The advantages of the present invention over the prior art are:

[0034] 1. The deflection control system of the hybrid rotary steerable drilling system that is easy to deflect is designed to control the radial push member of the front push assembly to push against the well wall in the radial direction of the front bearing body, so that the front bearing body generates a deflection angle relative to the input shaft of the universal joint with the center point of the universal joint as the center, thereby controlling the drilling direction and improving the deflection rate. Since the deflection angle only requires overcoming the relatively small force of the universal joint deflection, the pushing force of the front push assembly can be reduced, and the overall reliability of the system can be improved. In particular, for the dynamic offset method in which the front bearing body and the front push assembly rotate with the drill bit, since a smaller force is used to achieve the same guiding effect, the interaction force between the push member and the rock is reduced. Therefore, under the conditions of the same number of rotations and footage, the wear of the radial push member will be greatly reduced, thereby greatly reducing the probability of failure of the radial push member. At the same time, for the dynamic offset rotary guide driven by mud power, it also greatly reduces the system's demand for the pressure difference between the water hole and the annulus, which is of great help in reducing the overall pressure consumption of the tool and has great engineering significance and practical value.

[0035] 2. In the hybrid rotary steerable drilling system for easy deflection described herein, when the centralizer is positioned between the center point of the universal joint and the front push assembly, the push assembly causes the front support body to rotate about the universal joint, thereby changing the wellbore trajectory. The centralizer then provides support for the system. Furthermore, when the center point of the centralizer 5 coincides with the center point of the universal joint 21, deflection stability is further enhanced.

[0036] 3. In the easily deflectable hybrid rotary steerable drilling system described herein, the WOB torque deflection transmission sub is equipped with an elastic stabilizing device designed to prevent the front push assembly from driving the front bearing body to rotate about the center point of the universal joint. This further enhances system stability, enabling the easily deflectable hybrid rotary steerable drilling system to be used not only for wellbore deflection but also for conventional vertical well drilling, while also making the universal joint less susceptible to failure due to impact forces, WOB, and lateral vibration. At any rotation angle of the WOB torque deflection transmission sub, the restoring force provided by the elastic stabilizing device, which drives the universal joint input and output ends back to a coaxial state, must be greater than the radial force component generated at the rated maximum WOB at that angle.

[0037] 4. In the easy-to-deflect hybrid rotary steerable drilling system of the present invention, the weight-on-bit torque deflection transmission sub also includes a limiting mechanism 23 that limits the deflection angle to within the range of 0° to 5°. This mechanism is used to withstand the thrust of the rotary steerable hydraulic piston or the bending moment caused by vibration downhole, thereby extending the service life of the universal joint.

[0038] 5. The deflection control system for the easy-to-deflect hybrid rotary steerable drilling system of the present invention includes an electrical actuator for controlling the radial push of the front bearing body against the wellbore wall to generate a deflection force, an attitude measurement device for measuring the deflection angle of the universal joint, and a downhole computing device. The attitude measurement device, the electrical actuator, and the power supply are all electrically connected to a computing chip in the downhole computing device. The computing chip receives the deflection angle information collected by the attitude measurement device and compares it with the target deflection angle information to calculate the steering direction and steering force. The computing chip then controls the electrical actuator to cause the front bearing assembly to generate a combined thrust force against the wellbore wall opposite to the steering direction. Closed-loop control ensures that the universal joint angle and rotation amplitude of the weight-on-bit torque deflection transmission sub are consistent with preset values. The control strategy is simple, reliable, and easy to implement. Furthermore, because the pushing force of the front bearing assembly is relatively low, the electrical actuator can control the diversion device to alternately supply high-pressure drilling fluid in the main flow channel M to the hydraulic piston 42, thereby controlling the deflection of the front bearing body. This eliminates the need for an additional power source for the hydraulic piston of the front bearing assembly.

[0039] 6. The easy-to-inclination hybrid rotary steerable drilling system of the present invention can be configured to have two drilling pressure torque deflection transmission subs continuously arranged behind the front bearing body for wellbore with an inclination rate of less than 20 degrees / 30 meters, thereby greatly increasing the maximum rotation angle of the front bearing body relative to the input end of the universal joint and reducing the wear of the universal joint.

[0040] 7. The easy-to-inclination hybrid rotary steerable drilling system of the present invention aims to solve the problem of uncontrollable deep wellbore trajectory of ultra-short radius (wellbore curvature greater than 1 degree / meter) branch wells. By arranging a universal drilling torque transmission short section array behind the drilling torque deflection transmission short section, it adapts to high curvature while ensuring drilling torque transmission, and ensures the stability of wellbore trajectory control when guidance is required. It solves the contradiction between drilling torque transmission, adaptability to high curvature wellbores and stability of wellbore trajectory control. Moreover, the front-mounted bearing body, guidance implementation method, drilling torque deflection transmission short section and / or universal drilling torque transmission short section of the present invention are easy to miniaturize, and their lengths can be shortened or lengthened according to drilling requirements, thereby cooperating with the easy-to-inclination hybrid rotary steerable drilling system and the ability to adapt to wellbore curvatures with extremely high inclination rates and achieve stable control of the wellbore trajectory. It provides an effective means for wellbore trajectory control of the entire section of ultra-short radius branch wells. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 1 is a schematic axial cross-sectional view of Example 1 of the easy-to-deflect hybrid rotary steerable drilling system of the present invention;

[0042] Figure 2 It is an enlarged schematic diagram of the axial cross section of the weight-on-bit torque deflection transmission sub of the easy-to-deflect hybrid rotary steerable drilling system of the present invention;

[0043] Figure 3 1 is a schematic axial cross-sectional view of Example 4 of the easy-to-deflect hybrid rotary steerable drilling system of the present invention;

[0044] Figure 4 1 is a schematic axial cross-sectional view of Example 5 of the easy-to-deflect hybrid rotary steerable drilling system of the present invention;

[0045] Figure 5 2. It is a structural diagram of Example 6 of the easy-to-deflect hybrid rotary steerable drilling system of the present invention;

[0046] Figure 6 1 is a schematic axial cross-sectional view of Example 6 of the easy-to-deflect hybrid rotary steerable drilling system of the present invention;

[0047] Figure 7 2. FIG. 2 is a schematic cross-sectional view in the direction D of Example 6 of the easy-to-deflect hybrid rotary steerable drilling system of the present invention;

[0048] Figure 8 It is a partially enlarged schematic diagram of the axial cross-sectional diagram of Example 6 of the easy-to-deflect hybrid rotary steerable drilling system of the present invention.

[0049] The reference numerals are as follows:

[0050] 1-front bearing body, 11-drill bit, 111-drill bit connecting component, 112-universal joint connecting component, 12-guide sleeve, 121-radial thrust bearing, 122-axial thrust bearing, 13-center shaft;

[0051] 2-weight-on-bit torque deflection transmission sub, 21-universal joint, 211-output shaft, 212-input shaft, 22-elastic stabilizing device, 221-elastic tube, M-main channel, 222-leaf spring, 223-pressure-bearing seal, 23-limiting mechanism, 232-load-bearing drill collar housing, 24-fixing sleeve, 25-deflection space;

[0052] 2A - First WOB torque deflection transmission sub, 2B - Second WOB torque deflection transmission sub, 21A - Universal joint of first WOB torque deflection transmission sub, 21B - Universal joint of second WOB torque deflection transmission sub, 22A - First elastic stabilizer, 22B - Second elastic stabilizer, 26 - Anti-fouling seal; 27 - Anti-dropout part

[0053] 3- deflection control system, 31- electrical actuator, 311- motor, 312- electric rotary valve, 3121 rotary valve motor end, 3122- rotary valve follower end,

[0054] 32-attitude measurement device, 321-first accelerometer, 322-first magnetometer, 33-downhole computing device, 323-deflection sensor;

[0055] 4-front push assembly, 41-radial push member, 411-wing rib, 42-hydraulic piston;

[0056] 5- Centralizer,

[0057] 6-Power supply equipment, 61-Cables and energy transmission lines,

[0058] 7-Universal drilling pressure torque transmission short section,

[0059] 8-Main well. DETAILED DESCRIPTION

[0060] In order to facilitate understanding of the present invention, the following Figure 1-8 The present invention is described in more detail with reference to specific embodiments. The hybrid type of the easy-to-inclined hybrid rotary steering drilling system described in the present invention refers to a hybrid of push-type rotary steering and pointing-type rotary steering, and is not limited to dynamic offset mode and static offset mode.

[0061] Example 1

[0062] An easy-to-deflect hybrid rotary steering drilling system, first taking the dynamic offset rotary steering as an example, Figure 1As shown, the device comprises a front-end bearing body 1, a WOB torque deflection transmission sub 2, and a deflection control system 3. The WOB torque deflection transmission sub 2 includes a universal joint 21 and an elastic stabilizing device 22 that aligns the input and output shafts of the universal joint 21. A drill bit 11 is fixedly connected to the front end of the front-end bearing body 1. The drill bit 11 can be integrally formed with the front-end bearing body 1. The rear end of the front-end bearing body 1 is fixedly connected to the output shaft of the universal joint 21. Of course, the front-end bearing body 1 can also be integrally formed with the output shaft 211 of the universal joint 21. The input shaft 212 of the universal joint 21 can be directly fixedly connected to the drill string. Here, the output shaft 211 and input shaft 212 of the universal joint 21 rotate relative to the drill string as a whole, thereby driving the drill bit to rotate and transmitting WOB and torque to the drill bit. The circumferential surface of the front bearing body 1 is provided with a front pushing assembly 4; the deflection control system 3 controls the radial pushing member 41 of the front pushing assembly 4 to push the front bearing body 1 against the wellbore wall in the radial direction of the wellbore 1 to generate a radial pushing force. The radial pushing force overcomes the damping force of the elastic stabilizing device 22, causing the front bearing body 1 to generate a deflection angle relative to the input shaft 212 of the universal joint 21 with the center point of the universal joint 21 as the center, thereby achieving a hybrid steering function of the drill bit 11 with the advantages of push-type rotary steering and directional rotary steering, which can achieve a large inclination rate and accurate guidance, facilitating the control of the wellbore trajectory. It should be noted that the deflection angle is the composite angle of the well inclination angle and the azimuth angle required for deflection relative to the input shaft 212 of the universal joint 21.

[0063] For the generation and control of the deflection angle, the output shaft 211 of the universal joint 21 is exactly the input end of the deflection angle, that is, the radial pushing member 41 pushes against the well wall along the radial direction of the front bearing body 1 to generate a pushing deflection force, so that the front bearing body 1 drives the Figure 1 The output shaft 211 of the universal joint 21 deflects, generating a deflection angle. The present invention controls the drilling direction and improves the build rate by controlling the radial push member 41 to push against the wellbore wall in different directions, generating a push and deflection force that causes the drill bit 11 and the front support body 1 to rotate about the center point of the universal joint 21. Furthermore, since generating the deflection angle only requires overcoming the relatively small force that causes the universal joint 21 to deflect, the push force of the front push assembly 4 can be reduced, thereby improving the overall reliability of the system.

[0064] To effectively transmit the pushing action of the front pushing assembly 4 to the drill bit 11 and drive the drill bit 11 to rotate about the WOB torque deflection transmission sub 2, the average outer diameter of the front supporting body 1 is between 50% and 100% of the maximum outer diameter of the drill bit 11, and the front supporting body 1 must maintain a certain degree of rigidity. The front supporting body 1 may include a drill bit connection component 111 and a universal joint connection component 112. The universal joint connection component 112 may also be the output shaft of the universal joint or the bearing drill collar housing at the output end of the universal joint 21. This facilitates the placement of the power output structure of the hydraulic piston 42 of the front pushing assembly 4 within the front supporting body 1.

[0065] Example 2

[0066] Different from the above embodiment, Figure 1-4 As shown, the easy-to-deflect hybrid rotary steerable drilling system of the present invention further includes a centralizer 5 arranged behind the front pushing assembly 4, and the centralizer 5 is used to increase the deflection stability.

[0067] The centralizer 5 is preferably arranged between the front pushing component 4 and the center point of the universal joint 21. The deflection control system 3 controls the radial pushing member 41 of the front pushing component 4 to push the well wall radially along the front bearing body 1, so that the front bearing body 1 generates a deflection angle relative to the input shaft 212 of the universal joint 21 with the center point of the universal joint 21 as the center and the contact point of the centralizer 5 with the well wall as the fulcrum. At this time, the contact point from the drill bit to the centralizer 5 and the well wall is the force arm L1, and the contact point from the center point of the universal joint 21 to the centralizer 5 and the well wall is the force arm L2. The axial force of the rear drill string will generate a component force at the universal joint 21 to enhance the deflection. The component force is transmitted to the drill bit 11 through a lever with the centralizer 5 as the fulcrum, which can enhance the deflection.

[0068] Preferably, the center point of the centralizer 5 coincides with the center point of the universal joint 21 to further enhance the deflection stability.

[0069] If the center point of the centralizer 5 is located behind the center point of the universal joint, the axial distance between the center point of the centralizer 5 and the center point of the universal joint is not greater than 3 times the diameter of the drill bit. Within this range, sufficient deflection stability can still be guaranteed.

[0070] As a preference, Figure 1As shown, the front bearing body 1 and the WOB torque deflection transmission sub 2 are both hollow structures. The elastic stabilization device 22 includes an elastic tube 221 that passes through the hollow structure of the universal joint 21 and connects the input shaft 212 and output shaft 211 of the universal joint 21. The hollow structure of the front bearing body 1 and the through-hole of the elastic tube 221 form the main flow channel M for the circulation of drilling circulating medium.

[0071] The central through hole of the elastic tube 221 is used for flowing drilling circulating medium, and the wall thickness should be no less than 3 mm, so as to reliably prevent the front push assembly 4 from driving the front bearing body 1 to rotate around the center point of the universal joint 21, thereby increasing the stability of the system, so that the easy-to-inclined hybrid rotary directional drilling system can not only be used for wellbore inclination but also for conventional straight well drilling, and the universal joint 21 is not easy to fail under the action of impact force. And the elastic tube 221 can be reasonably selected according to the wellbore expansion situation, the inclination rate requirement and the drilling pressure situation to adjust the size of the universal joint 21 damping. In addition, the universal joint 21 of the present invention is not only able to flow drilling circulating medium, but also can pass through the cable and energy transmission line 61 to connect the well and the front push assembly 4, thereby providing power or signal transmission for the front push assembly 4. Specifically, the cable and energy transmission line 61 can be arranged in the side wall of the elastic tube 221. As a preference, Figure 1-2 As shown, the WOB torque deflection transmission sub 2 also includes a limiting mechanism 23 for limiting the deflection angle to within a range of 0° to 5°. The limiting mechanism 23 comprises a lever structure and a load-bearing drill collar housing 232. The lever structure contacts the inner wall of the load-bearing drill collar housing 232 to withstand the thrust of the rotary steerable hydraulic piston 42 or bending moments caused by downhole vibration. The lever structure can be formed by the output and input shafts of the universal joint 21 and the load-bearing drill collar housing 232 to limit the deflection of the output shaft of the universal joint 21.

[0072] At this time, if Figure 2 As shown, a deflection space 25 is generated between the lever structure and the inner wall of the bearing drill collar shell 232. Preferably, the elastic stabilizing device can also be a plurality of leaf springs 222 arranged in the deflection space 25. When the drill string causes the WOB torque deflection transmission sub 2 to deflect due to external force, that is, it immediately rotates relative to the bearing drill collar shell 232, the deflection space 25 is occupied, and the leaf spring 222 is compressed, thereby generating an elastic force that hinders the rotation of the WOB torque deflection transmission sub 2. This elastic force helps to restore the coaxial state of the two output shafts and the input shaft of the WOB torque deflection transmission sub 2, which is beneficial to the transmission of WOB torque and the protection of the WOB torque deflection transmission sub 2. Preferably, the output shaft 211 of the universal joint 21 and the rear end connection of the front bearing body 1 can be provided as follows. Figure 2The pressure-bearing seal 223 shown may be an extension structure of the leaf spring or an elastic sleeve structure similar to the leaf spring.

[0073] Preferably, the rigid universal joint includes a cross-axis universal joint, a ball cage universal joint, a ball fork universal joint or a ball hinge universal joint.

[0074] Example 3

[0075] Different from the above embodiment, the deflection control system 3 includes an electrical actuator 31 for controlling the radial pushing member 41 to push the front bearing body 1 radially against the well wall to generate a deflection force, a posture measurement device 32 for measuring the deflection angle of the universal joint, and a downhole computing device 33;

[0076] The downhole computing device 33 includes a computing chip electrically connected to the attitude measurement device 32, the electrical actuator device 31, and the power supply device 6. The computing chip receives the deflection angle information collected by the attitude measurement device 32 and compares it with the target deflection angle information to calculate the steering direction and steering force. This computing chip then controls the electrical actuator device 31 to cause the front-end push assembly 4 to generate a thrust force against the wellbore wall opposite to the steering direction. Through closed-loop control, the rotation angle and amplitude of the universal joint 21 of the weight-on-bit torque deflection transmission sub 2 are consistent with preset values, thereby controlling the wellbore trajectory. The closed-loop control algorithm is executed at a frequency between 0.5 and 60 seconds per cycle.

[0077] Preferably, the attitude measurement device 32 includes a deflection sensor 323 for measuring the rotational angle and direction of the universal joint 21 of the weight-on-bit torque deflection transmission sub 2. The corresponding deflection angle information includes the rotational direction and angle information of the front carrier body 1 relative to the universal joint input shaft 212, as measured by the deflection sensor 323. The target deflection angle information includes the rotational direction and angle information of the front carrier body 1 relative to the universal joint input shaft 212, pre-stored in the downhole computing device 33 or transmitted to the downhole computing device 33 via communication equipment. In this case, the deflection control system 3 tracks the changing process information of the deflection angle.

[0078] Alternatively, the attitude measurement device 32 includes a first accelerometer 321 and / or a first magnetometer 322 provided on the front supporting body 1. Specifically, the device can be placed on the front supporting body 1, preferably near the location of the front pushing assembly 4 on the front supporting body 1, to measure the attitude of the front supporting body 1. The corresponding deflection angle information includes the well inclination and azimuth information measured by the first accelerometer 321 and the first magnetometer 322. The target deflection angle information includes the target well inclination and azimuth information pre-stored in the downhole computing device 33 or transmitted to the downhole computing device 33 via communication equipment. In this case, the deflection control system 3 tracks the changes in the deflection angle.

[0079] The first accelerometer 321 and / or the first magnetometer 322 provided on the front supporting body 1 are used to measure the posture information of the front supporting body 1, namely the deflection angle information. This posture information is uploaded to the wellhead via a communication system for interaction with personnel and / or uploaded to a computing chip for wellbore trajectory control.

[0080] Or the attitude measurement device 32 includes, in addition to the first accelerometer 321 and / or the first magnetometer 322 provided on the front supporting body 1, a rear attitude measurement device provided behind the drilling pressure torque deflection transmission short section 2, and the rear attitude measurement device includes at least a set of second accelerometers and a set of second magnetometers, for achieving attitude measurement in an environment with less vibration and magnetic interference. At this time, the deflection angle information includes the well inclination information measured by the first accelerometer and the azimuth information measured by the second magnetometer, and the target deflection angle information includes the target well inclination information and target azimuth information pre-stored in the downhole computing device 33 or transmitted to the downhole computing device 33 via a communication device. The first accelerometer and the second accelerometer can be any one or a combination of quartz accelerometers or MEMS accelerometers. Because in drilling engineering, the well inclination control requirements are more stringent, and the azimuth control requirements are relatively loose. Therefore, the well inclination angle is measured by the first accelerometer on the front carrier body, and the azimuth angle can be measured by the first magnetometer on the front carrier body. The measurement result of the second magnetometer set at the rear can also be regarded as the azimuth angle at the front carrier body 1.

[0081] Preferably, the communication device can be any one or a combination of a mud pulse generator that transmits signals via mud pulses, an intelligent drill pipe, or an electromagnetic wave remote communication facility. The communication device is located behind the WOB torque deflection transmission sub 2 and is used to enable communication between the downhole computing device 33 and the wellhead equipment. The power supply device 6 includes a downhole turbine generator located behind the WOB torque deflection transmission sub 2, connected to the downhole computing device 33 via a cable and energy transmission line 61. In order to better and more safely implement the rotary steering function, the WOB torque deflection transmission sub 2 should be as short as possible, with at least one WOB torque deflection transmission sub 2 located within 4 meters of the drill bit.

[0082] Preferably, the front pushing assembly 4 is symmetrically provided with 2-6 groups on the central surface of the circumferential surface of the front bearing body 1, and the front pushing assembly 4 includes a hydraulic piston 42 and a radial pushing member 41, and the radial pushing member 41 includes a rib 411 or a hydraulic piston drive sleeve.

[0083] The hydraulic piston 42 is powered by drilling fluid, ie, drilling circulating medium. The electrical actuator 31 controls the diversion device to alternately provide the hydraulic piston 42 with high-pressure drilling fluid in the main channel M.

[0084] Preferably, the electrical actuator 31 includes a motor 311, an electric rotary valve 312, and a motor driver. The motor driver is located on a chip in the downhole computing device 33. The electric rotary valve 312 includes a rotary valve motor end 3121 and a rotary valve follower end 3122, each of which is provided with a flow hole. The motor driver adjusts the electric rotary valve 312 to a fixed direction based on control commands from the downhole computing device 33, i.e., rotates the rotary valve motor end 3121 relative to the rotary valve follower end 3122, causing the rotary valve motor end 3121 to divert mud through the flow hole of the diverter device, thereby controlling the hydraulic piston 42 of the front push assembly 4. For specific control methods, see U.S. Patent No. 2012 / 0160565A1 or U.S. Patent No. 005553679A.

[0085] Example 4

[0086] like Figure 2As shown, the easy-to-deflect hybrid rotary steerable drilling system of the present invention may include two WOB torque deflection transmission subsections 2 provided behind the front carrying body 1, namely a first WOB torque deflection transmission subsection 2A and a second WOB torque deflection transmission subsection 2B. The distance between the center point of the universal joint 21A of the first WOB torque deflection transmission subsection and the center point of the universal joint 21B of the second WOB torque deflection transmission subsection is less than 3 times the maximum diameter of the drill bit. The centralizer 5 is provided between the first WOB torque deflection transmission subsection 2A and the second WOB torque deflection transmission subsection 2B, or in front of the first WOB torque deflection transmission subsection 2A, or the center of the centralizer 5 coincides with the center point of the universal joint 21A of the first WOB torque deflection transmission subsection or the center point of the universal joint 21B of the second WOB torque deflection transmission subsection. When the centralizer 5 is arranged in front of the first WOB torque deflection transmission sub 2A, the distance between the center point of the centralizer 5 and the center point of the universal joint 21A of the first WOB torque deflection transmission sub shall not exceed 5 times the maximum diameter of the drill bit.

[0087] The input shaft of the universal joint 21A of the first WOB torque deflection transmission sub and the output shaft of the universal joint 21B of the second WOB torque deflection transmission sub are fixedly connected (including by threaded connection, integral molding, or other fixed connection methods). The fixed connection is covered by an anti-fouling seal 26, which can be an elastic sleeve that serves as an auxiliary component of the elastic stabilization device. The first WOB torque deflection transmission sub 2A includes a first elastic stabilization device 22A, and the second WOB torque deflection transmission sub 2B includes a second elastic stabilization device 22B. The first elastic stabilization device 22A extends through the universal joint 21A of the first WOB torque deflection transmission sub and can extend forward to the front support body 1. The second elastic stabilization device 22B extends through the universal joint 21B of the second WOB torque deflection transmission sub and can extend rearward to the drill string fixture.

[0088] Because the greater the rotation angle of the WOB torque deflection transmission sub 2, the lower its reliability. However, to ensure deflection, the front push assembly 4 must drive the front support body 1 to rotate as far as possible relative to the universal joint 21A of the first WOB torque deflection transmission sub 2, as close to the drill bit 11 as possible, achieving the highest possible rotation angle near the drill bit 11. Furthermore, to ensure the effectiveness of the WOB torque deflection transmission sub 2, the centralizing fulcrum of the centralizer 5 is essential. Therefore, the present invention proposes a centralized arrangement of double universal joints (21A and 21B), that is, the input shaft of the universal joint 21A of the first WOB torque deflection transmission subsection and the output shaft of the universal joint 21B of the second WOB torque deflection transmission subsection are both relatively short and directly fixedly connected, or the input shaft of the universal joint 21A of the first WOB torque deflection transmission subsection and the output shaft of the universal joint 21B of the second WOB torque deflection transmission subsection are directly integrally formed; and the first elastic stabilizing device 22A and the second elastic stabilizing device 22B are arranged in a "back-to-back" manner on the universal joint 21A of the first WOB torque deflection transmission subsection and the universal joint 21B of the second WOB torque deflection transmission subsection, combined with the centering effect of the stabilizer 5, thereby achieving the coordinated unification of the inclination stability, inclination rate and system reliability in most drilling requirements.

[0089] Example 5

[0090] The easy-to-deflect hybrid rotary steerable drilling system of the present invention can also be a static offset rotary steerable drilling system, specifically Figure 4As shown, the front bearing body 1 includes a guide sleeve 12 and a central shaft 13 that rotates freely in the guide sleeve 12 through a radial thrust bearing 121 and an axial thrust bearing 122. The front pushing assembly 4 is provided on the circumferential surface of the guide sleeve 12. The front end of the central shaft 13 is fixedly connected to the drill bit 11 (or the drill bit 11 and the central shaft 13 are formed as one piece), and the rear end is fixedly connected to the output shaft 211 of the universal joint 21 (or the central shaft 13 and the output shaft 211 of the universal joint 21 are formed as one piece). The drilling pressure torque deflection transmission short section 2 also includes a fixed sleeve 24 that is sleeved on the outside of the universal joint 21. A gap is provided between the fixed sleeve 24 and the universal joint 21 to form a deflection space 25. At this time, the fixed sleeve 24 can serve as a limiting mechanism 2 of the universal joint 21. 3, the deflection space 25 is created between the lever structure and the inner wall of the fixed sleeve 24. Preferably, the elastic stabilizing device can also be a plurality of leaf springs 222 disposed within the deflection space 25. When the drill string deflects the WOB torque deflection transmission sub 2 due to external force, the lever structure (which can be the lever structure formed by the output and input shafts of the universal joint 21 and the fixed sleeve 24) rotates relative to the fixed sleeve 24. The deflection space 25 is occupied, and the leaf springs 222 are compressed, thereby generating an elastic force that resists the rotation of the WOB torque deflection transmission sub 2. This elastic force helps restore the coaxiality of the output and input shafts of the WOB torque deflection transmission sub 2, facilitating the transmission of WOB torque and protecting the WOB torque deflection transmission sub 2. Preferably, the universal joint 21 can deflect 0° to 5° relative to the axis of the fixed sleeve 24 within the deflection space 25.

[0091] The centralizer 5 is arranged outside the guide sleeve 12 or the fixed sleeve 24, and when the centralizer 5 is located outside the fixed sleeve 24, the distance between its center point and the center point of the universal joint 21 is no more than 3 times the diameter of the drill bit.

[0092] Example 6

[0093] The easy-to-deflect hybrid rotary steerable drilling system, such as Figure 5-8As shown, the device further includes one or more interconnected universal WOB torque transmission subs 7 positioned behind the WOB torque deflection transmission sub. The structure of the universal WOB torque transmission subs 7 is identical to that of the WOB torque deflection transmission sub 2, including the universal joint 21, the elastic stabilization device 22, and the limit mechanism 23. Preferably, the universal WOB torque transmission subs 7 also include an elastic tube or other elastic stabilization device. In the static offset, easy-to-deflect rotary steering device, the universal WOB torque transmission subs 7 also include the fixed sleeve. This facilitates the drilling of ultra-short radius lateral wells from the sidewall of the main wellbore 8. If the main wellbore 8 has been cemented, pre-opening operations are required before drilling ultra-short radius lateral wells from the sidewall of the main wellbore 8. Sealing measures are added between the universal joints of each universal WOB torque transmission sub to prevent leakage of mud flowing through the hollow universal joints. Ultra-short radius lateral wells, as defined in the present invention, refer to lateral wells with a maximum wellbore curvature exceeding 1 degree / meter.

[0094] Preferably, the distance between the center points of the universal joints of the universal weight-on-bit torque transmission sub 7 should be less than 10 times the wellbore diameter.

[0095] Preferably, the plurality of interconnected universal WOD torque transmission subs 7 form a universal WOD torque transmission sub array, and the length of the universal WOD torque transmission sub array is greater than the length of the front bearing body 1. This arrangement can fully release the bending moment to help the front bearing body 1 and the WOD torque deflection transmission sub 2 adapt to the window generated by side drilling and the wellbore with large curvature. The safety of ultra-short radius branch well drilling technology is improved, and the risk of the front bearing body 1, the front push assembly 4 or the drill bit 11 getting stuck at the side drilling branch is avoided. Preferably, the one or more interconnected universal WOD torque transmission subs behind the WOD torque deflection transmission sub are all through structures, and the elastic stabilization device 22 can be an elastic flow tube of one or more interconnected universal WOD torque transmission subs that integrally penetrates the rear of the WOD torque deflection transmission sub.

[0096] Preferably, an anti-falling part 27 is provided at the connection between the drill pressure torque deflection transmission short section 2 and the front load-bearing body 1. Specifically, the anti-falling part 27 is an arc-shaped part, one end of which is clamped to the tail of the front load-bearing body 1, and the other end is clamped to the bearing drill collar shell of the drill pressure torque deflection transmission short section 2, so as to prevent the drill pressure torque deflection transmission short section 2 from falling off from the front load-bearing body 1 when the thrust of the radial pushing member 41 is too large, and can provide double protection for the deflection of the universal joint 21A of the first drill pressure torque deflection transmission short section.

[0097] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. An easy-to-deflect hybrid rotary steerable drilling system, characterized in that: The drill bit is rotated relative to the drill bit by the plurality of plurality of plurality of plurality of plurality of plurality of plurality of plurality of plurality of plurality of plurality of plurality of plurality of plurality of plurality of plurality of plurality of plurality of plurality of plurality of plurality of plurality of plurality of plurality of plurality of plurality of plurality of plurality of plurality of plurality of plurality of plurality of plurality of plurality of plurality of plurality of plurality of plurality of plurality of plurality of plurality of plurality of plurality of plurality of plurality of plurality of plurality of plurality of plurality of plurality of plurality of plurality of plurality of plurality of plurality of plurality of plurality of plurality of plurality of plurality of plurality of plurality of The front bearing body and the weight-on-bit torque deflection transmission sub are both through-structures, and the through-structures form a main channel for the circulation of drilling circulating medium; It also includes an elastic flow tube that passes through the hollow structure of the universal joint and connects the input end and the output end of the universal joint; and / or the drilling pressure torque deflection transmission short section also includes an elastic stabilization device that keeps the input shaft and the output shaft of the universal joint in a coaxial state; the elastic stabilization device includes an elastic tube that passes through the through structure of the universal joint and is coaxially connected to the input end and the output end of the universal joint.

2. The easy-to-deflect hybrid rotary steerable drilling system according to claim 1 is characterized in that The WOB torque deflection transmission sub and the universal WOB torque transmission sub both further include a limiting mechanism for limiting the deflection angle within a range of 0° to 5°.

3. The easy-to-deflect hybrid rotary steerable drilling system according to claim 1, characterized in that: It also includes a stabilizer arranged behind the front pushing assembly. If the center point of the stabilizer is located behind the center point of the universal joint, the distance between the center point of the stabilizer and the center point of the universal joint is not greater than 3 times the diameter of the drill bit; the deflection control system controls the radial pushing members of the front pushing assembly to push against the well wall along the radial direction of the front bearing body, so that the front bearing body generates a deflection angle relative to the input end axis of the universal joint with the center point of the universal joint as the center and the contact point between the centralizer and the well wall as the fulcrum.

4. The easy-to-deflect hybrid rotary steerable drilling system according to claim 2, characterized in that The limiting mechanism includes a lever structure and a supporting drill collar shell. A deflection space is generated between the lever structure and the inner wall of the supporting drill collar shell. The lever structure contacts the inner wall of the supporting drill collar shell and is used to withstand the thrust of the rotary steering hydraulic piston and / or the bending moment caused by the vibration downhole and / or the lateral component force caused by the bit pressure.

5. The easy-to-deflect hybrid rotary steerable drilling system according to claim 1, characterized in that: A movable gap is left between the elastic tube and the universal joint.

6. The easy-to-deflect hybrid rotary steerable drilling system according to claim 4, characterized in that: The elastic stabilization device includes a plurality of elastic rods centrally and symmetrically arranged on the inner surface of the bearing drill collar shell, and the elastic rods provide a restoring force to keep the input shaft and the output shaft of the universal joint in the same straight line; and / or the elastic stabilization device includes a plurality of leaf springs arranged in the deflection space between the lever structure and the bearing drill collar shell. When the deflection angle of the drilling pressure torque deflection transmission short section rotates to any angle in the range of 0° to 5°, the damping force provided by the elastic stabilization device to drive the input end and the output end of the universal joint to return to a coaxial state should be greater than the radial component force generated under the rated maximum drilling pressure at this angle.

7. The easy-to-deflect hybrid rotary steerable drilling system according to claim 1, characterized in that: The deflection control system includes an electrical actuator for controlling the radial pushing member to radially push the front supporting body against the well wall to generate a deflection force, a posture measurement device and a downhole computing device for measuring the deflection angle of the front supporting body; the downhole computing device includes a computing chip electrically connected to the posture measurement device, the electrical actuator and the power supply device.

8. The easy-to-deflect hybrid rotary steerable drilling system according to claim 7, characterized in that: The computing chip receives the deflection angle information collected by the attitude measurement device and compares it with the target deflection angle information to calculate the steering direction and steering force, and then controls the electrical actuator to make the front pushing component generate a thrust force opposite to the steering direction on the well wall. Through closed-loop control, the angle and rotation amplitude of the drilling pressure torque deflection transmission short section are consistent with the preset values, thereby controlling the wellbore trajectory.

9. The easy-to-deflect hybrid rotary steerable drilling system according to claim 8, characterized in that: The attitude measurement equipment includes a deflection sensor for measuring the universal joint angle and rotation direction of the drilling pressure torque deflection transmission short section, and the corresponding deflection angle information includes the rotation direction information and angle size information of the front bearing body relative to the universal joint input shaft measured by the deflection sensor; the target deflection angle information includes the rotation direction information and angle size information of the front bearing body relative to the universal joint input shaft pre-stored in the downhole computing device or transmitted to the downhole computing device through the communication device.

10. The easy-to-deflect hybrid rotary steerable drilling system according to claim 9, characterized in that: The attitude measurement device includes a first accelerometer and / or a first magnetometer provided on the front carrier body, and the corresponding deflection angle information includes the well inclination angle information and / or azimuth angle information measured by the accelerometer and / or magnetometer; the target deflection angle information includes the target well inclination angle information and / or target azimuth angle information of the front carrier body relative to the universal joint input axis, which is pre-stored in the downhole computing device or transmitted to the downhole computing device through the communication device.

11. The easy-to-deflect hybrid rotary steerable drilling system according to claim 10, characterized in that: The attitude measurement equipment includes an accelerometer and / or magnetometer arranged on the front carrying body, and also includes a rear attitude measurement equipment arranged behind the drilling pressure torque deflection transmission short section, and the rear attitude measurement equipment includes at least a group of second acceleration sensors and a group of second magnetometers, which are used to realize attitude measurement in an environment with less vibration and magnetic interference; the deflection angle information includes the well inclination angle information and azimuth angle information measured by the first accelerometer and the second magnetometer, and the target deflection angle information includes the target well inclination angle information and target azimuth angle information of the front carrying body relative to the universal joint input shaft, which are pre-stored in the downhole computing device or transmitted to the downhole computing device through the communication device.

12. The easy-to-deflect hybrid rotary steerable drilling system according to claim 3, characterized in that: The axial distance between the centralizer and the center point of the universal joint is less than or equal to 8 times the maximum diameter of the drill bit; and at least one of the weight-on-bit torque deflection transmission mechanisms is arranged within a range of 20 times the maximum diameter of the drill bit from the centralizer to the drill bit; and / or the average outer diameter of the front bearing body is 50%-100% of the outer diameter of the drill bit.

13. The easy-to-deflect hybrid rotary steerable drilling system according to claim 7, characterized in that: The front pushing assembly is symmetrically provided with 2-6 groups on the circumferential surface center of the front bearing body. The front bearing body and the pushing assemblies arranged on its surface rotate with the drill bit. The front pushing assembly includes a hydraulic piston and a radial pushing member. The radial pushing member includes a rib or a hydraulic piston drive sleeve. The hydraulic piston is powered by the drilling circulating medium in the main channel. The electrical actuator alternately provides the hydraulic piston with high-pressure drilling fluid in the main channel by controlling the diversion device.

14. The easy-to-deflect hybrid rotary steerable drilling system according to claim 13, characterized in that: The electrical actuator includes an electric motor, an electric rotary valve and a motor driver. The electric rotary valve includes a rotary valve motor end and a rotary valve follower end. The rotary valve motor end and the rotary valve follower end, and the motor driver are arranged on the downhole computing device. According to the control instructions of the downhole computing device, the rotary valve motor end is rotated relative to the rotary valve follower end, so that the rotary valve motor end is diverted through the diversion device to realize the control of the front rib assembly.

15. The easy-to-deflect hybrid rotary steerable drilling system according to claim 1, characterized in that: The universal joint is a cross-axis universal joint, a ball cage universal joint, a ball fork universal joint or a ball hinge universal joint.

16. The easy-to-deflect hybrid rotary steerable drilling system according to claim 7, characterized in that: The power supply equipment includes a downhole turbine generator, which is arranged behind the drilling pressure torque deflection transmission short section; and / or a communication device is also arranged behind the drilling pressure torque deflection transmission short section to realize communication between the downhole computing equipment and the wellhead equipment.

17. The easy-to-deflect hybrid rotary steerable drilling system according to claim 3, characterized in that: A first WOB torque deflection transmission subsection and a second WOB torque deflection transmission subsection are sequentially provided behind the front carrying body. The distance between the center points of the universal joints of the first WOB torque deflection transmission subsection and the second WOB torque deflection transmission subsection is less than 3 times the maximum diameter of the drill bit. The centralizer is arranged between the first WOB torque deflection transmission subsection and the second WOB torque deflection transmission subsection, or the centralizer is arranged in front of the first WOB torque deflection transmission subsection. The distance from the centroid of the universal joint in the first WOB torque deflection transmission subsection to the centroid of the drill bit is less than 20 times the maximum diameter of the drill bit. The input shaft of the universal joint of the first WOB torque deflection transmission subsection is fixedly connected to the output shaft of the universal joint of the second WOB torque deflection transmission subsection. The first WOB torque deflection transmission subsection includes a first elastic stabilization device, and the second WOB torque deflection transmission subsection includes a second elastic stabilization device.

18. The easy-to-deflect hybrid rotary steerable drilling system according to claim 3, characterized in that: The front bearing body includes a guide sleeve and a central shaft that rotates freely in the guide sleeve through a radial thrust bearing and an axial thrust bearing. The front pushing assembly is arranged on the circumferential surface of the guide sleeve. The front end of the central shaft is fixedly connected to the drill bit, and the rear end is fixedly connected to the output shaft of the universal joint. The drilling pressure torque deflection transmission short section also includes a limiting mechanism so that the universal joint can only deflect 0° to 5° relative to the axis of the fixed sleeve; the centralizer is arranged on the outside of the guide sleeve or the fixed sleeve, and the distance between the center point of the centralizer and the universal joint of the first drilling pressure torque deflection transmission short section is less than or equal to 2 meters.

19. The easy-to-deflect hybrid rotary steerable drilling system according to claim 1, characterized in that: The distance between the center points of the universal joints of the universal drilling pressure torque transmission short section is less than 10 times the maximum diameter of the drill bit; the distance from the centroid of the universal joint of the drilling pressure torque deflection transmission short section closest to the drill bit to the drill bit should be less than 15 times the maximum diameter of the drill bit.

20. The easy-to-deflect hybrid rotary steerable drilling system according to claim 19, characterized in that: The sum of the length of the universal weight-on-bit torque transmission sub array formed by the plurality of serially connected universal weight-on-bit torque transmission subs and the length of the front bearing body and the drill bit is greater than the length of the branch well section.

21. The easy-to-deflect hybrid rotary steerable drilling system according to claim 1, characterized in that: The WOB torque deflection transmission sub and the universal WOB torque transmission sub are both through structures, and the elastic stabilizing device passes through the WOB torque deflection transmission sub and the universal WOB torque transmission sub.

22. The easy-to-deflect hybrid rotary steerable drilling system according to claim 1, characterized in that: The WOB torque deflection transmission sub also includes an anti-dropping member, which is an arc-shaped member, one end of which is clamped to the bearing housing of the universal joint output end, and the other end of which is clamped to the bearing housing of the universal joint input end.

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