A self-vibrating drill bit flexible drilling tool

Abstract

The present invention discloses a self-vibrating drill-feeding flexible drilling tool proposed by the present invention, which relates to the technical field of flexible drilling tools and mainly includes a flexible drill string and a self-vibrating short section. The various parts are connected by a universal transmission mechanism to shorten the length of the rigid section of the overall drilling tool, which can meet the needs of small curvature radius guided drilling. Especially in the sliding guided drilling process, the self-vibrating short section can continuously generate vibrations, so that the downhole drill string produces creeping and reduces sliding friction, effectively avoiding the occurrence of sticking drill, which is conducive to the transmission of drilling pressure to the drill bit and improves the drilling time efficiency.

Description

Technical Field

[0001] The invention relates to the technical field of flexible drilling tools, and in particular to a self-vibrating drill-feeding flexible drilling tool. Background Art

[0002] In the field of oil and gas exploration, the application of directional drilling technology allows the wellbore to be drilled deep into the target layer according to the pre-designed trajectory. This technology requires the combination of downhole tools to complete directional, deflection, steady-angle drilling, horizontal drilling, etc., which can effectively develop thin oil and gas reservoirs and has more advantages than traditional vertical well exploration. For example, in the production of oil and natural gas, branch wells are drilled through directional drilling technology. On the basis of the pre-drilled main wellbore, several new branch wellbores can be formed at different well depths or different directions through deflection and directional drilling, so as to increase the oil leakage area of ​​the oil and gas reservoir. Oil and gas reservoirs with different well depths can also be developed in layers. In this way, the formation of branch wellbores through directional drilling is equivalent to increasing the channels for oil or gas production, which can significantly improve the development efficiency of oil and gas reservoirs, achieve the purpose of improving development efficiency, and improve economic benefits.

[0003] However, the current directional drilling tools will have a supporting pressure phenomenon during the drilling process, especially in the deflection section. Since the wellbore itself is curved in the deflection section, the drilling pressure cannot be applied to the drill bit during the application process or the pressurization effect is poor, causing the drilling process to get stuck or encounter resistance, resulting in slow drilling. Furthermore, due to the poor effect of the drilling power applied along the axial direction of the drill string, the friction resistance between the downhole drill bit and the well wall has become more and more significant in terms of drilling, especially in long well sections with small curvature radii. The additional torque and friction resistance caused by the friction between the drill bit and the well wall lead to low mechanical speed and even supporting pressure, which seriously affects the drilling speed. Therefore, there is an urgent need for a tool or technology to alleviate the supporting pressure and reduce the wear resistance of the drill string to improve the pressurization effect and increase the drilling efficiency. Summary of the invention

[0004] 1. Technical issues to be resolved

[0005] In order to overcome the shortcomings of the existing technology, a self-vibrating drill-feeding flexible drilling tool is proposed. By adopting a self-vibrating short section, the downhole drill string produces continuous axial creep to reduce sliding friction, avoid the occurrence of sticking drill, which is beneficial to applying drilling pressure and improving drilling efficiency.

[0006] (II) Technical solution

[0007] The present invention is implemented by the following technical solution: The present invention proposes a self-vibrating drill-feeding flexible drilling tool, comprising:

[0008] A flexible drill string, the flexible drill string comprising a plurality of mutually connected universal transmission short sections;

[0009] and at least one self-vibrating short sub, which is serially connected in the flexible drill string and includes a pulse module and an oscillation module, or a combination of a pulse module and a telescopic module, wherein the pulse module can continuously generate pressure pulses when high-pressure drilling fluid passes through, and the pressure pulses act on the oscillation module to generate continuous axial vibration or act on the telescopic module mechanism to generate continuous axial creep;

[0010] Furthermore, adjacent universal transmission short sections, the flexible drill string and the self-vibrating short section, and the pulse module and the oscillation module or the telescopic module are all connected via a universal transmission mechanism, and the sealing and stability of the drill string during vibration are ensured by elastic seals and a seismic self-stabilizing system.

[0011] Furthermore, the length of the self-vibrating short section is less than 5 times the diameter of the drill bit, and there is at least one universal transmission short section between it and the flexible drilling tools at both ends; the axial length from the drill bit to the uppermost universal transmission short section is greater than the preset length of the directional wellbore trajectory. It should be noted that the pulse module includes a rotatable rotor and a stator, and the rotor rotates relative to the stator, and the periodic throttling effect generated can realize hydraulic pulses; the telescopic module is a hydraulic piston; the oscillation module includes at least a housing, a core shaft and a spring group, and the spring group can generate damping and thrust to achieve oscillation when the housing and the core shaft move relative to each other.

[0012] Furthermore, the pulse module comprises an upper pulse joint and a lower pulse joint, a pulse rotating part composed of a rotating shaft and a pulse valve head is mounted inside the upper pulse joint, and an annular gap is arranged between the pulse rotating part and the upper pulse joint.

[0013] Furthermore, the pulse rotating part is composed of the rotating shaft and the pulse valve head connected by threads. Since the rotating shaft and the pulse valve head are both provided with shoulders, when the rotating shaft and the pulse valve head are connected and fixed, at least one blade group and a bearing group can be provided in the interval between the shoulders. The blade group is a turbine blade group, which can convert the energy of high-pressure drilling fluid into mechanical energy to drive the pulse rotating part to rotate.

[0014] The pulse lower joint is a hollow cylinder with stepped inner and outer shoulders, in which a pulse valve seat is fixedly arranged. The pulse valve seat and the pulse valve head together constitute a pulse valve group. When the pulse valve group is working, the pulse rotating part rotates while the pulse valve seat is fixed.

[0015] Furthermore, the pulse valve head and the pulse valve seat are both provided with flow passages that are interconnected, and the flow passages can connect the turbine blade flow passage and the internal flow passage of the pulse lower joint, so that the high-pressure drilling fluid can continue to flow forward into the internal flow passage space after flowing through the turbine blade flow passage and completing work;

[0016] When the rotating shaft drives the pulse valve head to rotate, since the pulse valve seat is fixed, the pulse valve head rotates relative to the pulse valve seat to generate periodic changes in the cross section of the flow channel, thereby generating a pulse pressure wave.

[0017] Furthermore, an upper bearing group, a lower bearing group, an adjustment ring and a clamping washer are arranged in the gap between the rotating shaft and the pulse upper joint;

[0018] Furthermore, the rotating shaft is a cylindrical structure with a thread at one end and an outer step at the other end. The outer step can be integrally formed or a shaft cap connected to the rotating shaft by a thread. When the rotating shaft is threadedly connected to the pulse valve head, the gap between the upper end surface of the pulse valve head and the outer step of the rotating shaft can compress and fix the blade group rotor and the inner rings of the bearings of the upper bearing group and the lower bearing group; the outer rings of the bearings of the blade group stator and the upper bearing group and the lower bearing group are compressed and fixed between the inner shoulder of the pulse lower joint and the lower connecting joint in the universal transmission mechanism by an adjusting ring and a compression washer, ensuring that when the turbine blade group is working, the high-pressure drilling fluid energy is converted into mechanical energy, driving the pulse rotating part to rotate while the pulse valve seat is fixed.

[0019] Furthermore, wear-resistant materials are provided between the friction surfaces of the pulse valve group or wear-resistant materials are partially provided.

[0020] Furthermore, the pulse module and the oscillation module or the pulse module and the telescopic module are connected via a universal transmission mechanism, and a free motion angle of the universal transmission mechanism is greater than 2°.

[0021] Furthermore, the oscillation module includes a core shaft, a shell, a lower joint and a spring clip group, wherein the core shaft is provided with at least two levels of external shoulders, and the drilling pressure is transmitted to the lower joint by one of the external shoulders; at least two levels of internal shoulders corresponding to the core shaft are provided in the shell, wherein the spring clip group is arranged in the annular space between the second level internal shoulder and the spring clip seat at the lower end of the core shaft, and the spring clip group can convert the pulse pressure wave into elastic potential energy, thereby generating axial vibration.

[0022] The spring sheet seat is fixed to the front end of the core shaft through threaded connection, and is inserted into the interior of the lower joint together with the core shaft to fit with the inner annulus thereof.

[0023] The core shaft, the two-stage shoulders on the shell, the spring seat and the inner annular space of the lower joint can all slide relative to each other, and the sliding surfaces are sealed by sealing elements.

[0024] The housing is threadedly connected and fixed to the lower joint; during the process of lowering the drilling tool, the weight of the lower drilling tool can be transferred from the housing to the spring sheet group through the lower joint, and at this time, the spring sheet group is compressed and accumulates potential energy, and then is continuously transferred backward by the spring sheet seat through the mandrel. Similarly, during the process of lifting the drilling tool, the pulling force from the rear is transferred from the mandrel through the spring sheet seat to the spring sheet group, and at this time, the spring sheet group is also compressed and accumulates potential energy, and then is continuously transferred forward by the housing through the lower joint.

[0025] The lower joint is provided with a throat constriction inside. When the pulse valve group is working, the pressure-bearing surface of the throat constriction generates a periodic axial force under the action of the pressure pulse, and the force acts on the pressure-bearing surface of the throat constriction and the lower surface of the spring plate seat at the same time, so that the spring plate group generates a periodic axial displacement, thereby forming a continuous axial vibration.

[0026] Furthermore, the telescopic module comprises a piston, a cylinder and a drill feed joint. The piston reciprocates in the cylinder under the action of the pulse pressure wave, and its axial displacement can be transmitted downward through the drill feed joint to cause the drill string to creep.

[0027] Furthermore, the cylinder body includes an upper joint of the cylinder liner, an outer shell of the cylinder liner and a lower joint of the cylinder liner, and the upper joint of the cylinder liner, the outer shell of the cylinder liner and the lower joint of the cylinder liner are fixed by threaded connection to form a stepped inner annulus; the piston is a hollow cylinder as a whole, and a stepped outer step is provided on the outside of the piston and is sleeved in the interior of the cylinder body, and the stepped outer step is located in the stepped inner annulus to form a piston chamber; the piston chamber is connected to a low-pressure throttling hole or a nozzle provided on the outer shell of the cylinder liner, so that when the pressure pulse is high pressure, a pressure difference is formed between the upper and lower surfaces of the piston, pushing the piston downward, and transmitting the pressure to the drill feed joint.

[0028] Furthermore, the piston is threadedly connected and fixed to the drill feed joint. During the process of lowering the drill tool, the weight of the lower drill tool is transferred from the drill feed joint to the piston. At this time, the piston moves downward, and its stepped outer step is in close contact with the upper end surface of the cylinder liner lower joint to complete the force transfer. Similarly, when lifting the drill tool, the axial lifting force is transferred from the cylinder liner lower joint to the piston, and at this time, the stepped outer step is in close contact with the upper end surface of the cylinder liner lower joint to complete the force transfer.

[0029] Furthermore, when a pulse occurs, the pressure pulse acts on the piston surface, causing the pressure difference between the upper and lower surfaces of the piston to change periodically, thereby forming continuous axial creep.

[0030] (III) Beneficial effects

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] The self-vibrating drill-feeding flexible drilling tool proposed in the present invention mainly includes a flexible drill string and a self-vibrating short section. The various parts are connected by a universal transmission mechanism to shorten the length of the rigid section of the overall drill tool, which can meet the needs of small curvature radius guided drilling. It is particularly suitable for guided drilling. Since the self-vibrating short section can continuously generate axial vibration, the downhole drill string will creep and reduce sliding friction, effectively avoiding the occurrence of sticking drill, which is conducive to applying drilling pressure and improving drilling efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments made with reference to the following drawings:

[0034] Figure 1 It is a schematic diagram of the overall structure of a self-vibrating drill-feeding flexible drilling tool;

[0035] Figure 2 It is a schematic diagram of the first structure of a self-vibrating drill-feeding flexible drilling tool;

[0036] Figure 3 A second structural schematic diagram of a self-vibrating drill-feeding flexible drilling tool;

[0037] In the figure: 1-bottom hole power drilling tool; 2-universal transmission short section; 4-self-vibration short section; 5-drill bit; 6-rigid drill string; 7-pulse module; 8-oscillation module; 9-rotating shaft; 10-pulse upper joint; 11-pulse lower joint; 12-pulse valve head; 13-blade group; 14-upper bearing group; 15-lower bearing group; 16-universal transmission mechanism; 16a-upper connecting joint; 16b-lower connecting joint; 16c-ball seat; 16d-elastic sealing element; 16e-ball head;

[0038] 17-guide nipple; 17a-guide mechanism; 18-adjusting ring; 19-pressing washer; 20-pulse valve seat; 21-core shaft; 22-housing; 23-lower joint; 24-shrapnel group; 25-telescopic module; 26-shrapnel seat; 27-piston; 28-cylinder body; 28a-cylinder sleeve upper joint; 28b-cylinder sleeve shell; 28c-and cylinder sleeve lower joint;

[0039] 29-drill feed joint; 30-stepped inner annulus; 31-stepped outer step; 32-piston chamber; 33-low-pressure throttling hole or nozzle; 34-wear-resistant material; 35-piston sealing system; 36-anti-seismic self-stabilizing system; M-pulse flow channel; N-liquid distribution flow channel; 37-power output shaft. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0041] Example 1: Please refer to Figure 1 , 2 3. The present invention provides a self-vibrating drill-feeding flexible drilling tool, comprising:

[0042] A flexible drill string, wherein the flexible drill string comprises a plurality of universal transmission short sections 2 which are serially connected to each other.

[0043] And at least one self-vibrating short section 4, the self-vibrating short section 4 is connected in series in the flexible drill string. Preferably, the self-vibrating short section 4 in this embodiment is connected in series in the lower position of the overall drilling tool assembly. During the drilling process, the axial vibration generated by the self-vibrating short section 4 located in the lower position can change the friction state between the lower drilling tool and the well wall, making it easier to transmit the drilling pressure to the bottom hole drill bit 5. The self-vibrating short section 4 includes a pulse module 7 and an oscillation module 8, wherein the pulse module 7 can continuously generate pressure pulses when high-pressure drilling fluid passes through, and the pressure pulses act on the oscillation module 8 to generate continuous axial vibration or act on the hydraulic piston mechanism in the telescopic module 25 to generate continuous axial creep;

[0044] Preferably, this embodiment is used in the process of directional drilling, and other downhole power drilling tools 1 can also be matched at the lowest end of the flexible drill string. Preferably, the downhole power drilling tool 1 in this embodiment is a turbine, and the flexible drill string and the downhole power drilling tool 1 are connected by a universal transmission short section 2. The downhole power drilling tool 1 also includes a guide short section 17 or a guide mechanism 17a, whose power is transmitted to the drill bit 5 through a power output shaft 37 hinged to the power output shaft of the downhole power drilling tool 1 to complete the directional drilling;

[0045] In order to improve the passability of the overall drilling tool assembly in a wellbore trajectory with a small curvature radius, the adjacent universal transmission short sections 2, the flexible drill string and the self-vibration short section 4, and the pulse module 7 and the oscillation module 8 or the telescopic module 25 are all connected through a universal transmission mechanism 16, and the elastic seal 16d and the seismic self-stabilization system 36 are used to ensure the sealing and stability of the drill string during vibration.

[0046] Preferably, the universal transmission short section 2 in this embodiment includes at least an upper connecting joint 16a and a lower connecting joint 16b, and the upper connecting joint 16a and the lower connecting joint 16b are connected via a universal transmission mechanism 16, and the universal transmission mechanism 16 should include a seismic self-stabilizing system 36. Preferably, the seismic system 36 can be a spring.

[0047] In this embodiment, the length of the self-vibrating short section 4 is less than 5 times the diameter of the drill bit, and there is at least one universal transmission short section 2 between it and the flexible drilling tools at both ends; the axial length from the drill bit to the uppermost universal transmission short section is greater than the preset length of the directional wellbore trajectory.

[0048] In this embodiment, the pulse module 7 includes a pulse upper joint 10 and a pulse lower joint 11. The pulse upper joint 10 is internally provided with a pulse rotating part composed of a rotating shaft 9 and a pulse valve head 12, and an annular gap is provided between the pulse rotating part and the pulse upper joint 10.

[0049] Preferably, the pulse rotating part is formed by the rotating shaft 9 and the pulse valve head 12 being connected by threads. Since the rotating shaft 9 and the pulse valve head 12 are both provided with shoulders, when the rotating shaft 9 and the pulse valve head 12 are connected and fixed, at least one blade group and a bearing group can be provided in the interval between the shoulders. The blade group is a turbine blade group, which can convert the energy of the high-pressure drilling fluid into mechanical energy to drive the pulse rotating part to rotate.

[0050] Furthermore, the pulse lower joint 11 is a hollow cylinder provided with stepped inner and outer shoulders, and a pulse valve seat 20 is fixedly provided inside the cylinder. The pulse valve seat 20 and the pulse valve head 12 together constitute a pulse valve group. When the pulse valve group is working, the pulse rotating part rotates while the pulse valve seat 20 is fixed.

[0051] In addition, the pulse valve head 12 and the pulse valve seat 20 are both provided with flow passages that are interconnected, and the flow passages can connect the turbine blade flow passage and the internal flow passage of the pulse lower joint 11, so that the high-pressure drilling fluid can continue to flow forward into the internal flow passage space after flowing through the turbine blade flow passage and completing work;

[0052] When the rotating shaft 9 drives the pulse valve head to rotate, since the pulse valve seat 20 is fixed, the pulse valve head rotates relative to the pulse valve seat to generate periodic changes in the cross section of the flow channel, thereby generating a pulse pressure wave.

[0053] In particular, an upper bearing group 14, a lower bearing group 15, an adjustment ring 18 and a compression washer 19 are also arranged in the gap between the rotating shaft 9 and the pulse upper joint 10;

[0054] The rotating shaft is a cylindrical structure with a thread at one end and an outer step at the other end. The outer step can be integrally formed or a shaft cap connected to the rotating shaft 9 by a thread. When the rotating shaft is threadedly connected to the pulse valve head, the interval between the upper end surface of the pulse valve head 12 and the outer step of the rotating shaft 9 can press and fix the blade group rotor and the inner rings of the upper bearing group 14 and the lower bearing group 15; the outer rings of the bearings of the blade group stator and the upper bearing group 14 and the lower bearing group 15 are pressed and fixed between the inner shoulder of the pulse lower joint 11 and the lower connecting joint 16b in the universal transmission mechanism 16 by the adjusting ring and the pressing washer ring, ensuring the stability of the blade group 13 and the rotating shaft 9. Under the action of the turbine blade group, the high-pressure drilling fluid energy is converted into mechanical energy, driving the pulse rotating part to rotate while the pulse valve seat 20 is fixed.

[0055] Preferably, wear-resistant material 34 is provided between the friction surfaces of the pulse valve group or wear-resistant material is partially provided to ensure the service life of the pulse valve group.

[0056] In this embodiment, the pulse module and the oscillation module are connected via a universal transmission mechanism, and the free movement angle of the universal transmission mechanism is greater than 2°.

[0057] In this embodiment, the oscillation module 8 includes a mandrel 21, a housing 22, a lower joint 23 and a spring piece group 24, which is hinged with the pulse lower joint 11 through a universal transmission mechanism 16, specifically including a ball head 16e and a ball seat 16c, the outer shoulder of the pulse lower joint 11 is provided with a ball head 16e, the upper end of the mandrel 21 is provided with an inner shoulder, and a ball seat 16c is provided in the inner shoulder, the surfaces of the ball head 16e and the ball seat 16c fit and slide with each other, and the drilling pressure transmission under the deflection condition can be realized, wherein the mandrel 21 is provided with at least two levels of outer shoulders, and the drilling pressure is transmitted to the lower joint 23 by one of the outer shoulders;

[0058] At least two levels of inner shoulders corresponding to the core shaft 21 are arranged in the shell 22, wherein the spring group 24 is arranged in the annular space between the second level inner shoulder and the spring seat 26 at the lower end of the core shaft 21, and the spring group 24 can convert the pulse pressure wave into elastic potential energy, thereby generating axial vibration.

[0059] Preferably, the spring seat 26 is fixed to the front end of the core shaft 21 by threaded connection, and is inserted into the interior of the lower joint 23 together with the core shaft 21 to fit the inner annulus thereof.

[0060] The core shaft 21, the two-stage shoulders on the housing 22, the spring seat 26 and the inner annular space of the lower joint 23 can all slide relative to each other, and the sliding surfaces are sealed by sealing members.

[0061] The housing 22 is threadedly connected and fixed to the lower joint 23; during the process of lowering the drilling tool, the weight of the lower drilling tool can be transferred from the housing 22 to the spring sheet group 24 through the lower joint 23. At this time, the spring sheet group 24 is compressed and accumulates potential energy, and then is continuously transferred backward by the spring sheet seat 26 through the mandrel 21. Similarly, during the process of lifting the drilling tool, the pulling force from the rear is transferred from the mandrel 21 through the spring sheet seat 26 to the spring sheet group 24. At this time, the spring sheet group 24 is also compressed and accumulates potential energy, and then is continuously transferred forward by the housing 22 through the lower joint 23.

[0062] A throat neck is provided inside the lower joint 23. When the pulse valve group is working, the pressure-bearing surface of the throat neck generates a periodic axial force under the action of the pressure pulse. The force acts on the pressure-bearing surface of the throat neck and the lower surface of the shrapnel seat 26 at the same time, causing the shrapnel group 24 to generate periodic axial displacement, thereby forming continuous axial vibration.

[0063] Example 2: Figure 3 , which is different from the first embodiment in that the self-vibration in the present embodiment is generated by connecting the telescopic module 25 below the pulse module 7, and using the pressure pulse to make the telescopic module 25 produce continuous reciprocating motion in the axial direction to form axial vibration. When the pressure is high, the pressure wave acts on the upper surface of the piston 27 to form an axial thrust to push the piston 27 out, driving the drill feed joint 29 downward. When the pressure is low, the extended piston 27 will be retracted into the telescopic module 25 due to the forward resistance of the lower drill tool, and this is repeated. Specifically, the telescopic module 25 includes a piston 27, a cylinder body 28 and a drill feed joint 29. The cylinder body 28 includes a cylinder liner upper joint 28a, a cylinder liner outer shell 28b and a cylinder liner lower joint 28c. The cylinder liner upper joint 28a, the cylinder liner outer shell 28b and the cylinder liner lower joint 28c are connected. The piston 27 is a hollow cylinder as a whole, and a stepped outer step 31 is arranged on the outside thereof and is sleeved inside the cylinder body 28, and the stepped outer step 31 is located in the stepped inner annulus 30 to form a piston chamber 32; the piston chamber 32 is connected to a low-pressure throttling hole or a nozzle 33 arranged on the cylinder shell 28b, so that when the pressure pulse is high pressure, a pressure difference is formed between the upper and lower surfaces of the piston, pushing the piston 27 downward, and transmitting the pressure to the drill feed joint 29.

[0064] Furthermore, the piston 27 is threadedly connected and fixed to the drill feed joint 29. During the process of lowering the drill tool, the weight of the lower drill tool is transferred from the drill feed joint 29 to the piston 27. At this time, the piston 27 moves downward, and its stepped outer step 31 is in close contact with the upper end surface of the cylinder liner lower joint 28c to complete the force transmission. Similarly, when lifting the drill tool, the axial lifting force is transferred from the cylinder liner lower joint 28c to the piston 27. At this time, the stepped outer step 31 is in close contact with the upper end surface of the cylinder liner lower joint 28c to complete the force transmission.

[0065] Furthermore, when a pulse occurs, the pressure pulse acts on the piston surface, causing the pressure difference between the upper and lower surfaces of the piston 27 to change periodically, thereby forming a continuous axial creep.

[0066] Further, such as Figure 2 As shown, the self-vibrating short section 4 includes a pulse module 7 and an oscillation module 8, and the pulse module and the oscillation module are connected by a universal transmission mechanism; or Figure 3 As shown, the self-oscillating short section 4 includes a pulse module 7 and a telescopic module 25, and the pulse module and the telescopic module are connected by a universal transmission mechanism.

[0067] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic features of the present invention. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is defined by the attached claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention. Any figure mark in the claims should not be regarded as limiting the claims involved.

[0068] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A self-vibrating drill-feeding flexible drilling tool, characterized in that: include: A flexible drill string, the flexible drill string comprising a plurality of universal transmission short sections (2) connected in series with each other; and at least one self-vibrating short joint (4), the self-vibrating short joint (4) being connected in series in the flexible drill string; the self-vibrating short joint (4) comprising a pulse module (7), or the self-vibrating short joint (4) comprising a pulse module (7) and an oscillation module (8), or the self-vibrating short joint (4) comprising a pulse module (7) and a telescopic module (25); wherein the pulse module (7) is capable of continuously generating pressure pulses when high-pressure drilling fluid passes through; the pressure pulses act on the oscillation module (8) to generate continuous axial vibration, or act on the telescopic module (25) mechanism to generate axial creep; Adjacent universal transmission short sections (2) and the universal transmission short sections (2) and the self-oscillating short sections (4) are connected via a universal transmission mechanism (16); The telescopic module (25) comprises a piston (27), a cylinder (28) and a drill feed joint (29); the piston (27) reciprocates in the cylinder (28) under the action of a pulse pressure wave, and its axial displacement can be transmitted downward through the drill feed joint (29) to cause the drill string to creep; The cylinder body (28) comprises a cylinder liner upper joint (28a), a cylinder liner outer shell (28b) and a cylinder liner lower joint (28c), wherein the cylinder liner upper joint (28a), the cylinder liner outer shell (28b) and the cylinder liner lower joint (28c) are fixed by threaded connection and form a stepped inner annulus (30); the piston (27) is a hollow cylinder as a whole, and is provided with a stepped outer step (31) on the outside and is sleeved inside the cylinder body (28), and the stepped outer step (31) is located in the stepped inner annulus (30) to form a piston chamber (32); the piston chamber (32) is communicated with a low-pressure throttling hole or a bumper (33) provided on the cylinder liner outer shell (28b), so that when the pressure pulse is high pressure, a pressure difference is formed between the upper and lower surfaces of the piston, pushing the piston (27) downward, and transmitting the pressure to the drill feed joint (29).

2. The self-vibrating drill bit flexible drilling tool according to claim 1, characterized in that: The length of the self-vibrating short section (4) is less than 5 times the diameter of the drill bit, and there is at least one universal transmission short section (2) between it and the flexible drilling tools at both ends; the axial length from the drill bit to the uppermost universal transmission short section is greater than the preset length of the directional wellbore trajectory.

3. The self-vibrating drill-feeding flexible drilling tool according to claim 1, characterized in that: The pulse module (7) comprises a pulse rotating part; The pulse rotating part is composed of a rotating shaft (9) and a pulse valve head (12) connected by threads, and the rotating shaft (9) is connected to at least one blade group and a bearing group, and the blade group is a turbine blade group, which can convert the energy of high-pressure drilling fluid into mechanical energy to drive the pulse rotating part to rotate; A pulse valve seat (20) is fixedly arranged inside the pulse module, and the pulse valve seat (20) and the pulse valve head (12) together form a pulse valve group. When the pulse valve group is working, the pulse rotating part rotates while the pulse valve seat (20) remains fixed.

4. The self-vibrating drill-feeding flexible drilling tool according to claim 3, characterized in that: The pulse valve head (12) and the pulse valve seat (20) are both provided with flow passages that are interconnected, and the flow passages can connect the turbine blade flow passage and the internal flow passage of the pulse lower joint (11), so that the high-pressure drilling fluid can continue to flow forward into the internal flow passage space after flowing through the turbine blade flow passage and completing work; When the rotating shaft (9) drives the pulse valve head to rotate, since the pulse valve seat (20) is fixed, the pulse valve head rotates relative to the pulse valve seat to generate a periodic change in the cross section of the flow channel, thereby generating a pulse pressure wave.

5. A self-vibrating drill-feeding flexible drilling tool according to claim 3 or 4, characterized in that: An upper bearing group (14), a lower bearing group (15), an adjustment ring (18) and a pressing washer (19) are also arranged in the gap between the rotating shaft (9) and the pulse upper joint (10); The gap between the upper end surface of the pulse valve head (12) and the outer step of the rotating shaft (9) can be used to press and fix the blade group rotor and the inner rings of the bearings of the upper bearing group (14) and the lower bearing group (15); the blade group stator and the outer rings of the bearings of the upper bearing group (14) and the lower bearing group (15) are pressed and fixed between the inner shoulder of the pulse lower joint (11) and the lower connecting joint (16b) in the universal transmission mechanism (16) by the adjusting ring (18) and the pressing washer (19), so as to ensure that when the turbine blade group is working, the high-pressure drilling fluid energy is converted into mechanical energy, driving the pulse rotating part to rotate while the pulse valve seat (20) is fixed.

6. The self-vibrating drill-feeding flexible drilling tool according to claim 4, characterized in that: The friction surfaces of the pulse valve group are provided with wear-resistant materials or wear-resistant materials are partially provided.

7. The self-vibrating drill-feeding flexible drilling tool according to claim 1, characterized in that: The pulse module and the oscillation module or the pulse module and the telescopic module are connected via a universal transmission mechanism, and a free motion angle of the universal transmission mechanism is greater than 2°.

8. A self-vibrating drill-feeding flexible drilling tool according to claim 1 or 7, characterized in that: The oscillation module (8) comprises a core shaft (21), a shell (22), a lower joint (23) and a spring group (24); the spring group (24) can convert pulse pressure waves into elastic potential energy, thereby generating axial vibration.

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