Mechanical impact and water jet combined grooving stress unloading drilling device and drilling method

Abstract

The present invention discloses a mechanical impact and water jet combined grooving stress unloading drilling device and a drilling method, belonging to the technical field of oil drilling engineering. The device includes a boosting mechanism, an impact mechanism, and a drill bit. The impact mechanism includes an upper sub, a casing, and a lower sub. An impact hammer is fitted in the middle of the upper sub, and a transmission mandrel is fitted in the middle of the lower sub. The drill bit includes a matrix. A grooving outer cylinder is coaxially and fixedly arranged at the bottom end of the radial outer side of the matrix. PDC teeth are arranged on the matrix, and a plurality of impregnated diamonds are arranged on the grooving outer cylinder along the circumferential direction. When the drill bit reaches the bottom of the well, the impregnated diamonds contact the bottom of the well prior to the PDC teeth. A conventional flow channel is arranged on the matrix, and a conventional nozzle is arranged at the bottom end of the conventional flow channel. A high-pressure hose passes through the inner cavities of the upper sub, the casing, the transmission mandrel, the matrix, and the grooving outer cylinder and then a high-pressure nozzle is arranged. The present invention can realize annular grooving of the bottom-hole rock to unload the stress of the bottom-hole rock and combined rock breaking by mechanical impact and ultra-high-pressure water jet, thereby greatly improving the drilling rate.

Description

Technical Field

[0001] The invention belongs to the technical field of oil drilling engineering, and particularly relates to a drilling device and a drilling method for combined mechanical impact and water jet grooving stress unloading. Background Technique

[0002] In the process of oil and gas field development, drilling is a key link. As the well depth increases, the rock mass in the basement area is subjected to the combined action of strong in-situ stress and hydrostatic pressure, which makes the rock more plastic and harder. This strengthening effect of the bottom-hole rock caused by stress increases the drilling cycle and drilling cost. Coupled with the abrasiveness and natural heterogeneity of the rock matrix, the drilling rate is greatly reduced. Existing technologies usually increase the rock-breaking efficiency and improve the drilling rate through single mechanical impact or ultra-high-pressure jet, but the rock-breaking efficiency of each of these two methods is limited by physical conditions and it is difficult to achieve the best rock-breaking effect.

[0003] Therefore, how to reduce the compressive effect on the bottom-hole rock under the combined action of in-situ stress and hydrostatic column pressure, reduce the difficulty of rock fragmentation, and thus improve the mechanical drilling rate is the research direction of current drilling technology.

[0004] Based on this, the present application proposes a drilling device and a drilling method for combined mechanical impact and water jet grooving stress unloading, which can realize the circumferential grooving of the bottom-hole rock to unload the stress of the bottom-hole rock and the combined rock-breaking of mechanical impact and ultra-high-pressure water jet, thereby greatly improving the drilling rate. Summary of the Invention

[0005] The purpose of the invention is to overcome the deficiencies of the above-mentioned prior art and provide a drilling device for combined mechanical impact and water jet grooving stress unloading.

[0006] To achieve the above purpose, the invention adopts the following technical scheme:

[0007] The drilling device for combined mechanical impact and water jet grooving stress unloading includes a pressurizing mechanism, an impact mechanism, and a drill bit that are connected in sequence from top to bottom along the axial direction;

[0008] A first normal pressure flow channel and a first pressurizing flow channel are arranged in the pressurizing mechanism, and the lower end of the first pressurizing flow channel is connected to a high-pressure hose;

[0009] The impact mechanism includes an upper sub, a casing, and a lower sub that are coaxially and fixedly connected in sequence. The upper end of the upper sub is fixedly connected to the lower end of the pressurizing mechanism. The upper sub is provided with a second normal pressure flow channel that penetrates axially. An impact hammer is slidably fitted axially in the middle of the upper sub. A disc spring is arranged between the stepped end face of the outer wall of the impact hammer and the stepped end face of the inner wall of the upper sub. A drive mandrel is slidably and sealingly fitted axially in the middle of the lower sub. A second through hole for connecting the inner cavity of the casing and the inner cavity of the drive mandrel is provided at the upper end of the drive mandrel. The bottom end of the impact hammer and the upper end of the drive mandrel are located in the inner cavity of the casing to achieve the transmission of impact.

[0010] The drill bit includes a matrix fixedly connected coaxially with the drive mandrel. A cutting groove outer cylinder is coaxially and fixedly arranged at the bottom end of the radial outer side of the matrix. PDC teeth are arranged on the matrix. A number of impregnated diamonds are evenly arranged on the cutting groove outer cylinder along the circumferential direction. When the drill bit reaches the bottom of the well, the impregnated diamonds contact the bottom of the well prior to the PDC teeth.

[0011] A conventional flow channel that penetrates the bottom end and is connected to the inner cavity of the drive mandrel is arranged on the matrix. A conventional nozzle is arranged at the bottom end of the conventional flow channel.

[0012] The high-pressure hose is provided with a high-pressure nozzle after passing through the upper sub, the inner cavity of the casing, the drive mandrel, the matrix, and the cutting groove outer cylinder.

[0013] Preferably, the pressurizing mechanism includes an outer cylinder body. Inside the outer cylinder body, there are a rotating drive shaft, a conversion joint, a power conversion cylinder, a filter cylinder, a plunger, and a sleeve from top to bottom in sequence.

[0014] The rotating drive shaft is coaxially and fixedly connected to the outer cylinder body. The conversion joint is coaxially and fixedly arranged at the lower end of the rotating drive shaft. The lower part of the conversion joint is connected to the power conversion cylinder through a matching structure. The matching structure converts the rotational movement of the conversion joint into the axial reciprocating movement of the power conversion cylinder.

[0015] The filter cylinder is fixedly arranged at the bottom end of the power conversion cylinder. The upper part of the plunger is fixedly arranged at the bottom end of the inner cavity of the filter cylinder. The sleeve is coaxially and fixedly connected to the outer cylinder body. A plunger hole for matching with the plunger is arranged in the middle of the sleeve. A liquid inlet check valve is arranged at the bottom end of the inner cavity of the plunger. A high-pressure sleeve is fixedly arranged at the bottom end of the plunger hole. A liquid outlet check valve is arranged at the bottom end of the plunger hole.

[0016] The inner cavities of the rotating drive shaft, the conversion joint, and the power conversion cylinder are connected. An annular cavity is formed between the filter cylinder and the outer cylinder body. A sleeve flow channel that penetrates axially is arranged on the sleeve. A first flow hole for connecting its inner cavity with the annular cavity is arranged on the power conversion cylinder. A second flow hole for connecting its inner cavity with the annular cavity is arranged on the filter cylinder. The inner cavities of the filter cylinder and the plunger are connected.

[0017] The inner cavity of the connected rotating transmission shaft, the inner cavity of the adapter, the inner cavity of the power conversion cylinder, the first flow hole, the annular cavity, and the sleeve flow channel form the first atmospheric pressure flow channel; the second flow hole, the inner cavity of the filter cartridge, the inner cavity of the plunger, the plunger hole, and the inner cavity of the high-pressure casing form the first pressurized flow channel.

[0018] Preferably, the filter cartridge has a cylindrical structure with a sealed top end.

[0019] Preferably, a first through hole for connecting the second atmospheric pressure flow channel and the inner cavity of the upper joint and a bypass flow channel penetrating from the inner cavity of the upper joint to the outside are provided on the upper joint below the disc spring, and a bypass nozzle is provided in the bypass flow channel.

[0020] Preferably, a sealing cap is fixedly provided at the top end of the inner cavity of the upper joint.

[0021] Preferably, a plurality of cutter wings are uniformly arranged along the circumferential direction at the bottom end of the matrix, and a plurality of PDC teeth are provided on each cutter wing.

[0022] Preferably, a plurality of gauge protection parts are uniformly arranged along the circumferential direction on the outside of the grooving outer cylinder. The gauge protection parts include an outer arc gauge protection part axially extending along the radial outer wall surface of the grooving outer cylinder, an inner arc gauge protection part axially extending along the radial inner wall surface of the grooving outer cylinder, and a connecting part connecting the bottom ends of the outer arc gauge protection part and the inner arc gauge protection part;

[0023] A plurality of impregnated diamonds are uniformly arranged along the generatrix extension direction on the outer side surfaces of the outer arc gauge protection part, the inner arc gauge protection part, and the connecting part.

[0024] Preferably, the radial outer wall surfaces of all the outer arc gauge protection parts are located on the same cylindrical surface, and the radial inner wall surfaces of all the inner arc gauge protection parts are located on the same cylindrical surface.

[0025] Preferably, the radial cross-section of the connecting part has a semi-circular ring structure.

[0026] The present invention also provides a drilling method for stress unloading by combined mechanical impact and water jet grooving.

[0027] The drilling method for stress unloading by combined mechanical impact and water jet grooving is implemented based on a drilling device for stress unloading by combined mechanical impact and water jet grooving. The drilling method includes the following steps:

[0028] Step 1, when the drill bit reaches the bottom of the well, the impregnated diamonds at the bottom end of the grooving outer cylinder contact the bottom of the well prior to the PDC teeth;

[0029] Apply the drilling pressure and torque. Under the combined action of the drilling fluid pressure in the casing, the bottom hole thrust on the drill bit, and the disc spring, the impact hammer realizes pulsed impact on the drill bit, and the pressurizing mechanism pressurizes the drilling fluid and then forms a high-pressure jet through spraying via the first pressurized flow channel, the high-pressure hose, and the high-pressure nozzle;

[0030] Under the combined action of the weight on bit, torque, pulse impact, and high-pressure jet, the impregnated diamond cuts a circular groove on the bottom end face of the wellbore, unloading the bottom-hole pressure;

[0031] Step 2: The drill bit continues to drill, the depth of the circular groove continuously deepens, and the PDC teeth start to contact the bottom-hole rock inside the circular groove and break it;

[0032] Step 3: Under the combined action of the weight on bit, torque, pulse impact, and high-pressure jet, the impregnated diamond continues to cut the circular groove, and the PDC teeth continue to break the rock inside the circular groove, achieving combined rock breaking;

[0033] During this process:

[0034] The drilling fluid is ejected outward along the first normal flow channel, sleeve flow channel, casing inner cavity, second through hole, transmission mandrel inner cavity, conventional flow channel, and conventional nozzle, transporting the broken cuttings to the annulus.

[0035] The beneficial effects of the present invention are:

[0036] Through the combined setting of the pressurizing mechanism, impact mechanism, and drill bit, the present invention realizes cutting a circular groove on the bottom-hole rock surface, releasing the local stress of the bottom-hole rock, and reducing the difficulty of the bottom-hole drill bit "penetrating" into the rock formation during drilling; at the same time, the mechanical impact generated by the impact mechanism can cause cracks on the bottom-hole rock surface, thereby reducing the threshold pressure for the ultra-high-pressure jet to cut into the rock; ultimately, it realizes stress unloading of the bottom-hole rock by cutting a circular groove on the bottom-hole rock, and combined rock breaking by mechanical impact and ultra-high-pressure water jet, thus greatly improving the drilling rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The schematic diagrams in the specification forming a part of this application are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an improper limitation to this application.

[0038] Figure 1 is a schematic structural diagram of the drilling device for combined cutting groove stress unloading of mechanical impact and water jet of the present invention;

[0039] Figure 2 is a schematic structural diagram of the drill bit in the present invention;

[0040] Figure 3 is Figure 2 a sectional view taken along the A-A direction of

[0041] Figure 4 is a schematic structural diagram of the gauge protection part in the present invention;

[0042] Wherein:

[0043] 11. First atmospheric pressure flow channel; 12. First pressurization flow channel; 13. High-pressure hose; 131. High-pressure nozzle; 14. Outer cylinder; 15. Rotating transmission shaft; 16. Adapter; 17. Power conversion cylinder; 171. First flow hole; 18. Filter cylinder; 181. Second flow hole; 19. Plunger; 191. Inlet check valve; 192. High-pressure sleeve; 193. Outlet check valve; 110. Sleeve; 1101. Sleeve flow channel;

[0044] 21. Upper joint; 211. Second atmospheric pressure flow channel; 212. First through hole; 213. Bypass flow channel; 214. Bypass nozzle; 215. Sealing cap; 22. Casing; 23. Lower joint; 24. Impact hammer; 241. Seal; 25. Disc spring; 26. Drive mandrel; 261. Second through hole; 262. Anvil cap cover plate;

[0045] 31. Matrix; 311. Conventional flow channel; 312. Conventional nozzle; 32. Grooved outer cylinder; 33. PDC teeth; 34. Impregnated diamond; 35. Blade; 36. Gauge section; 361. Outer arc gauge section; 362. Inner arc gauge section; 363. Connecting section. Detailed implementation manners

[0046] It should be noted that the following detailed description is exemplary and is intended to provide further illustration of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this application belongs.

[0047] It should be noted that the terms used herein are only for the purpose of describing specific implementation manners and are not intended to limit the exemplary implementation manners according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "include" and / or "comprise" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0048] In the present invention, terms such as "upper", "lower", "bottom", "top", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only relationship terms determined for the convenience of describing the structural relationship of each component or element of the present invention, and do not specifically refer to any component or element in the present invention, and should not be construed as a limitation on the present invention.

[0049] In the present invention, terms such as "connected" and "joined" should be understood in a broad sense, indicating that it can be a fixed connection, an integral connection or a detachable connection; it can be directly connected or indirectly connected through an intermediate medium. For those related scientific research or technical personnel in the field, the specific meanings of the above terms in the present invention can be determined according to specific circumstances, and should not be construed as a limitation on the present invention.

[0050] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0051] Embodiment 1:

[0052] As Figure 1 shown, a combined mechanical impact and water jet grooving stress unloading drilling device includes a pressurizing mechanism, an impact mechanism, and a drill bit that are connected in sequence from top to bottom along the axial direction;

[0053] A first atmospheric pressure flow channel 11 and a first pressurizing flow channel 12 are arranged in the pressurizing mechanism, and the lower end of the first pressurizing flow channel 12 is connected to a high-pressure hose 13;

[0054] The impact mechanism includes an upper joint 21, a casing 22, and a lower joint 23 that are coaxially and fixedly connected in sequence. The upper end of the upper joint 21 is fixedly connected to the lower end of the pressurizing mechanism. A second atmospheric pressure flow channel 211 that penetrates axially is arranged on the upper joint 21, and the second atmospheric pressure flow channel 211 is used to connect the first atmospheric pressure flow channel 11 and the cavity of the casing 22. An impact hammer 24 is slidably fitted axially in the middle of the upper joint 21. A disc spring 25 is arranged between the stepped end face of the outer wall of the impact hammer 24 and the stepped end face of the inner wall of the upper joint 21. The upper end of the disc spring 25 abuts against and is fixedly connected to the stepped end face of the inner wall of the upper joint 21, and the lower end of the disc spring 25 abuts against and is fixedly connected to the stepped surface of the outer wall of the impact hammer 24. A seal 241 is arranged between the outer wall of the impact hammer 24 above the disc spring 25 and the inner wall of the upper joint 21. A transmission core shaft 26 is slidably and sealingly fitted axially in the middle of the lower joint 23. The transmission core shaft 26 and the lower joint 23 achieve axial sliding fit and torque transmission through splines. A second through hole 261 for connecting the inner cavity of the casing 22 and the inner cavity of the transmission core shaft 26 is arranged at the upper end of the transmission core shaft 26; the bottom end of the impact hammer 24 and the upper end of the transmission core shaft 26 are located in the inner cavity of the casing 22 to achieve the transmission of impact; specifically, an anvil cap cover plate 262 is arranged at the upper end of the transmission core shaft 26 to prevent the transmission core shaft 26 from slipping out of the lower joint 23 downward;

[0055] The drill bit includes a matrix 31 that is coaxially and fixedly connected to the transmission core shaft 26. A grooving outer cylinder 32 is coaxially and fixedly arranged at the bottom end of the radial outer side of the matrix 31. PDC teeth 33 are arranged on the matrix 31. A plurality of impregnated diamonds 34 are uniformly arranged on the grooving outer cylinder 32 along the circumferential direction; when the drill bit reaches the bottom of the well, the impregnated diamonds 34 contact the bottom of the well prior to the PDC teeth 33;

[0056] A conventional flow channel 311 that penetrates the bottom end and is communicated with the inner cavity of the transmission core shaft 26 is arranged on the matrix 31, and a conventional nozzle 312 is arranged at the bottom end of the conventional flow channel 311;

[0057] The high-pressure hose 13 is provided with a high-pressure nozzle 131 after passing through the upper joint 21, the inner cavity of the casing 22, the transmission mandrel 26, the base body 31, and the grooved outer cylinder 32.

[0058] Preferably, the pressurizing mechanism includes an outer cylinder 14. Inside the outer cylinder 14, from top to bottom, there are a rotating transmission shaft 15, a conversion joint 16, a power conversion cylinder 17, a filter cylinder 18, a plunger 19, and a sleeve 110. The bottom end of the outer cylinder 14 is coaxially and fixedly connected to the top end of the upper joint 21.

[0059] The rotating transmission shaft 15 is coaxially and fixedly connected to the outer cylinder 14. The conversion joint 16 is coaxially and fixedly arranged at the lower end of the rotating transmission shaft 15. The lower part of the conversion joint 16 is connected to the power conversion cylinder 17 through a matching structure. The outer wall of the power conversion cylinder 17 is in sliding fit with the inner wall of the outer cylinder 14. The matching structure converts the rotational movement of the conversion joint 16 into the axial reciprocating movement of the power conversion cylinder 17. The matching structure that converts the rotational movement of the conversion joint 16 into the axial reciprocating movement of the power conversion cylinder 17 is a prior art and will not be elaborated here. For example, a pin shaft is provided on the power conversion cylinder 17, and a cylindrical cam groove matching with the pin shaft is provided on the conversion joint 16 to achieve the conversion between rotational movement and axial reciprocating movement.

[0060] The filter cylinder 18 is fixedly arranged at the bottom end of the power conversion cylinder 17. The upper part of the plunger 19 is fixedly arranged at the bottom end of the inner cavity of the filter cylinder 18. The sleeve 110 is coaxially and fixedly connected to the outer cylinder 14. A plunger hole matching with the plunger 19 is provided in the middle of the sleeve 110. A liquid inlet check valve 191 is arranged at the bottom end of the inner cavity of the plunger 19. A high-pressure sleeve 192 is fixedly arranged at the bottom end of the plunger hole. A liquid outlet check valve 193 is arranged at the bottom end of the plunger hole.

[0061] The inner cavities of the rotating transmission shaft 15, the conversion joint 16, and the power conversion cylinder 17 are connected. An annular cavity is formed between the filter cylinder 18 and the outer cylinder 14. An axially penetrating sleeve flow channel 1101 is provided on the sleeve 110. A first flow hole 171 for connecting its inner cavity with the annular cavity is provided on the power conversion cylinder 17. A second flow hole 181 for connecting its inner cavity with the annular cavity is provided on the filter cylinder 18. The inner cavities of the filter cylinder 18 and the plunger 19 are connected.

[0062] The connected inner cavities of the rotating transmission shaft 15, the conversion joint 16, the power conversion cylinder 17, the first flow hole 171, the annular cavity, and the sleeve flow channel 1101 form a first atmospheric pressure flow channel 11. The second flow hole 181, the inner cavity of the filter cylinder 18, the inner cavity of the plunger 19, the plunger hole, and the inner cavity of the high-pressure sleeve 192 form a first pressurizing flow channel 12. The upper end of the high-pressure hose 13 is connected to the bottom end of the high-pressure sleeve 192.

[0063] In this application, the principle of generating ultra-high pressure jet is as follows:

[0064] In the initial state, the inlet check valve 191 and the outlet check valve 193 are both closed. The drilling fluid enters the inner cavity of the plunger 19 along the inner cavity of the rotating transmission shaft 15, the inner cavity of the adapter 16, the inner cavity of the power conversion cylinder 17, the first flow hole 171, the annular cavity, the second flow hole 181, and the inner cavity of the filter cylinder 18. During the upward movement of the plunger 19 following the filter cylinder 18 and the power conversion cylinder 17, the inlet check valve 191 opens, and the drilling fluid enters the plunger hole between the bottom end of the plunger 19 and the outlet check valve 193. During the downward movement of the plunger 19 following the filter cylinder 18 and the power conversion cylinder 17, the inlet check valve 191 closes. When the pressure of the drilling fluid in the plunger hole between the bottom end of the plunger 19 and the outlet check valve 193 reaches a certain value, the outlet check valve 193 opens, so that the pressurized drilling fluid is ejected along the high-pressure casing 192, the high-pressure hose 13, and the high-pressure nozzle 131 to form a jet.

[0065] With the axial reciprocating operation of the plunger 19, a pulsed ultra-high pressure jet is formed.

[0066] Preferably, the filter cylinder 18 is in a cylindrical structure with a sealed top end.

[0067] Preferably, on the upper joint 21 below the disc spring 25, there is a first through hole 212 for communicating the second normal pressure flow channel 211 and the inner cavity of the upper joint 21, and a bypass flow channel 213 that penetrates from the inner cavity of the upper joint 21 to the outside. A bypass nozzle 214 is arranged in the bypass flow channel 213.

[0068] Preferably, a sealing cap 215 is fixedly arranged at the top end of the inner cavity of the upper joint 21.

[0069] Preferably, as Figures 2 - 4 shown, a plurality of cutter wings 35 are uniformly arranged along the circumferential direction at the bottom end of the matrix 31, and a plurality of PDC teeth 33 are arranged on each cutter wing 35.

[0070] Preferably, a plurality of gauge protection parts 36 are uniformly arranged along the circumferential direction on the grooving outer cylinder 32. The gauge protection parts 36 include an outer arc gauge protection part 361 that axially extends along the radial outer wall surface of the grooving outer cylinder 32, an inner arc gauge protection part 362 that axially extends along the radial inner wall surface of the grooving outer cylinder 32, and a connecting part 363 that connects the bottom end of the outer arc gauge protection part 361 and the bottom end of the inner arc gauge protection part 362;

[0071] A plurality of impregnated diamonds 34 are uniformly arranged on the outer side surfaces of the outer arc gauge protection part 361, the inner arc gauge protection part 362, and the connecting part 363 along the generatrix extension direction.

[0072] Preferably, the radial outer wall surfaces of all the outer arc diameter retaining portions 361 are located on the same cylindrical surface, and the radial inner wall surfaces of all the inner arc diameter retaining portions 362 are located on the same cylindrical surface.

[0073] Preferably, the radial cross-section of the connecting portion 363 is in a semi-annular structure.

[0074] Embodiment 2:

[0075] A drilling method of combined mechanical impact and water jet grooving stress unloading is implemented based on a drilling device of combined mechanical impact and water jet grooving stress unloading. The drilling method includes the following steps:

[0076] Step 1, when the drill bit reaches the bottom of the well, the impregnated diamond 34 at the bottom end of the grooving outer cylinder 32 contacts the bottom of the well prior to the PDC tooth 33.

[0077] Apply the drilling pressure and torque. Under the combined action of the drilling fluid pressure in the casing 22, the bottom hole thrust on the drill bit, and the disc spring 25, the impact hammer 24 realizes pulsed impact on the drill bit. After the pressurizing mechanism pressurizes the drilling fluid, it forms a high-pressure jet through the first pressurizing flow path 12, the high-pressure hose 13, and the high-pressure nozzle 131.

[0078] Under the combined action of the drilling pressure, torque, pulsed impact, and high-pressure jet, the impregnated diamond 34 cuts a circular groove on the bottom end face of the drilling bottom hole to unload the bottom hole pressure.

[0079] Step 2, the drill bit continues to drill, the depth of the circular groove continues to deepen, and the PDC tooth 33 starts to contact the bottom hole rock inside the circular groove and break it.

[0080] Step 3, under the combined action of the drilling pressure, torque, pulsed impact, and high-pressure jet, the cutting of the circular groove by the impregnated diamond 34 and the breaking of the rock inside the circular groove by the PDC tooth 33 continue, realizing combined rock breaking.

[0081] During this process:

[0082] The drilling fluid sprays outwards along the first normal pressure flow path 11, the sleeve flow path 1101, the inner cavity of the casing 22, the second through hole 261, the inner cavity of the drive mandrel 26, the normal flow path 311, and the normal nozzle 312, washes the impregnated diamond 34 and the PDC tooth 33, and then transports the broken rock cuttings to the annulus.

[0083] Through the combined setting of a pressurizing mechanism, an impact mechanism, and a drill bit, the present invention realizes circumferential grooving on the bottom-hole rock surface, releases the local stress of the bottom-hole rock, and reduces the difficulty of the bottom-hole drill bit "penetrating" into the rock formation during the drilling process. At the same time, the mechanical impact generated by the impact mechanism can cause cracks to appear on the bottom-hole rock surface by the drill bit, thereby reducing the threshold pressure for the ultra-high-pressure water jet to cut into the rock. Ultimately, circumferential grooving of the bottom-hole rock is realized to unload the stress of the bottom-hole rock, and rock breaking is achieved through the combination of mechanical impact and ultra-high-pressure water jet, thereby significantly improving the drilling rate.

[0084] Although the specific implementation manners of the present invention are described above in conjunction with the accompanying drawings, it is not a limitation to the present invention. Those skilled in the art should understand that, based on the technical solutions of the present invention, various modifications or deformations that can be made by those skilled in the art without creative efforts are still within the protection scope of the present invention.

Claims

1. A mechanical impact and water jet combined grooving stress unloading drilling device, characterized in that It includes a pressurizing mechanism, an impact mechanism, and a drill bit that are connected in sequence from top to bottom along the axis. A first normal pressure flow channel and a first pressurizing flow channel are arranged in the pressurizing mechanism, and the lower end of the first pressurizing flow channel is connected to a high-pressure hose. The impact mechanism includes an upper joint, a casing, and a lower joint that are coaxially and fixedly connected in sequence. The upper end of the upper joint is fixedly connected to the lower end of the pressurizing mechanism. A second normal pressure flow channel that penetrates axially is arranged on the upper joint. An impact hammer is slidably fitted axially in the middle of the upper joint. A disc spring is arranged between the stepped end face of the outer wall of the impact hammer and the stepped end face of the inner wall of the upper joint. A transmission core shaft is slidably and sealingly fitted axially in the middle of the lower joint. A second through hole for communicating the inner cavity of the casing and the inner cavity of the transmission core shaft is arranged at the upper end of the transmission core shaft. The bottom end of the impact hammer and the upper end of the transmission core shaft are located in the inner cavity of the casing to achieve the transmission of impact. The drill bit includes a matrix that is coaxially and fixedly connected to the transmission core shaft. A grooving outer cylinder is coaxially and fixedly arranged at the bottom end of the radial outer side of the matrix. PDC teeth are arranged on the matrix. A number of impregnated diamonds are evenly arranged on the grooving outer cylinder along the circumferential direction. When the drill bit reaches the bottom of the well, the impregnated diamonds contact the bottom of the well prior to the PDC teeth. A conventional flow channel that penetrates the bottom end and is communicated with the inner cavity of the transmission core shaft is arranged on the matrix, and a conventional nozzle is arranged at the bottom end of the conventional flow channel. The high-pressure hose is provided with a high-pressure nozzle after passing through the upper joint, the inner cavity of the casing, the transmission core shaft, the matrix, and the grooving outer cylinder.

2. The mechanical impact and water jet combined grooving stress unloading drilling device according to claim 1, characterized in that, The pressurizing mechanism includes an outer cylinder body. Inside the outer cylinder body, there are a rotating transmission shaft, a conversion joint, a power conversion cylinder, a filter cylinder, a plunger, and a sleeve from top to bottom in sequence. The rotating transmission shaft is coaxially and fixedly connected to the outer cylinder body. The conversion joint is coaxially and fixedly arranged at the lower end of the rotating transmission shaft. The lower part of the conversion joint is connected to the power conversion cylinder through a matching structure, and the matching structure converts the rotational movement of the conversion joint into the axial reciprocating movement of the power conversion cylinder. The filter cylinder is fixedly arranged at the bottom end of the power conversion cylinder. The upper part of the plunger is fixedly arranged at the bottom end of the inner cavity of the filter cylinder. The sleeve is coaxially and fixedly connected to the outer cylinder body. A plunger hole that cooperates with the plunger is arranged in the middle of the sleeve. A liquid inlet one-way valve is arranged at the bottom end of the inner cavity of the plunger. A high-pressure sleeve is fixedly arranged at the bottom end of the plunger hole. A liquid outlet one-way valve is arranged at the bottom end of the plunger hole. The inner cavities of the rotating transmission shaft, the conversion joint, and the power conversion cylinder are connected and communicated. An annular cavity is formed between the filter cylinder and the outer cylinder body. A sleeve flow channel that penetrates axially is arranged on the sleeve. A first flow hole for connecting its inner cavity with the annular cavity is arranged on the power conversion cylinder. A second flow hole for connecting its inner cavity with the annular cavity is arranged on the filter cylinder. The inner cavities of the filter cylinder and the plunger are connected and communicated. The connected inner cavity of the rotating transmission shaft, the inner cavity of the conversion joint, the inner cavity of the power conversion cylinder, the first flow hole, the annular cavity, and the sleeve flow channel form a first normal pressure flow channel; the second flow hole, the inner cavity of the filter cylinder, the inner cavity of the plunger, the plunger hole, and the inner cavity of the high-pressure sleeve form a first pressurizing flow channel.

3. The mechanical impact and water jet combined grooving stress unloading drilling device according to claim 2, characterized in that, The filter cylinder is in a cylindrical structure with a sealed top end.

4. The mechanical impact and water jet combined grooving stress unloading drilling device according to claim 1, characterized in that, A first through hole for communicating with a second normal pressure flow path and the inner cavity of the upper joint, and a bypass flow path penetrating from the inner cavity of the upper joint to the outside are provided on the upper joint below the disc spring, and a bypass nozzle is provided in the bypass flow path.

5. The mechanical impact and water jet combined grooving stress unloading drilling device according to claim 1, wherein A sealing cap is fixedly provided at the top end of the inner cavity of the upper joint.

6. The mechanical impact and water jet combined grooving stress unloading drilling device according to claim 1, wherein, A plurality of cutter wings are uniformly arranged along the circumferential direction at the bottom end of the matrix, and a plurality of PDC teeth are arranged on each cutter wing.

7. The mechanical impact and water jet combined grooving stress unloading drilling device according to claim 1, characterized in that, A plurality of gauge protection parts are uniformly arranged along the circumferential direction on the cutting groove outer cylinder. The gauge protection parts include an outer arc-shaped gauge protection part axially extending along the radial outer wall surface of the cutting groove outer cylinder, an inner arc-shaped gauge protection part axially extending along the radial inner wall surface of the cutting groove outer cylinder, and a connecting part connecting the bottom ends of the outer arc-shaped gauge protection part and the inner arc-shaped gauge protection part; A plurality of impregnated diamonds are uniformly arranged on the outer side surfaces of the outer arc-shaped gauge protection part, the inner arc-shaped gauge protection part, and the connecting part along the generatrix extension direction.

8. The mechanical impact and water jet combined grooving stress unloading drilling device according to claim 7, characterized in that, The radial outer wall surfaces of all the outer arc-shaped gauge protection parts are located on the same cylindrical surface, and the radial inner wall surfaces of all the inner arc-shaped gauge protection parts are located on the same cylindrical surface.

9. The mechanical impact and water jet combined grooving stress unloading drilling device according to claim 8, wherein The radial cross section of the connecting part is in a semi-circular ring structure.

10. The method for stress unloading drilling by combined mechanical impact and water jet grooving is implemented based on the combined mechanical impact and water jet grooving stress unloading drilling device according to any one of claims 2 to 9, and is characterized in that, The drilling method includes the following steps: Step 1: When the drill bit reaches the bottom of the well, the impregnated diamonds at the bottom end of the cutting groove outer cylinder contact the bottom of the well prior to the PDC teeth. Apply drilling pressure and torque. Under the combined action of the drilling fluid pressure in the casing, the bottom hole thrust on the drill bit, and the disc spring, pulsed impact of the impact hammer on the drill bit is achieved, and after the pressurizing mechanism pressurizes the drilling fluid, it is sprayed through the first pressurizing flow path, the high-pressure hose, and the high-pressure nozzle to form a high-pressure jet. Under the combined action of the drilling pressure, torque, pulsed impact, and high-pressure jet, the impregnated diamonds cut a circular groove on the bottom end face of the drilling well bottom to unload the bottom hole pressure. Step 2: The drill bit continues to drill, the depth of the circular groove continuously deepens, and the PDC teeth start to contact the bottom hole rock inside the circular groove and break it. Step 3: Under the combined action of the drilling pressure, torque, pulsed impact, and high-pressure jet, the cutting of the circular groove by the impregnated diamonds and the breaking of the rock inside the circular groove by the PDC teeth continue, achieving combined rock breaking. During this process: The drilling fluid is sprayed out along the first normal pressure flow path, the sleeve flow path, the inner cavity of the casing, the second through hole, the inner cavity of the transmission mandrel, the normal flow path, and the normal nozzle, and the broken rock cuttings are transported to the annulus.

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