Directional PDC drill bit for shale gas exploitation

Abstract

The invention relates to the technical field of shale gas exploitation, and discloses a directional PDC (polycrystalline diamond compact) drill bit for shale gas exploitation, which mainly comprises a drill bit base, a PDC drill bit body and a drill bit connecting pipe, and is provided with a quick disassembly and assembly mechanism, a tunneling mechanism and a drill bit base protection mechanism, the rapid dismounting and mounting mechanism realizes rapid dismounting and mounting of the PDC drill bit body through cooperation of a clamping telescopic column, an auxiliary spring, a bayonet socket and other parts, the maintenance time is shortened, the resource consumption is reduced, the tunneling mechanism comprises blades, reinforced drill teeth, chip removal and heat dissipation grooves and a rotary jet nozzle, and the rotary jet nozzle can enable drilling fluid to be subjected to high-speed rotary jet flow; a chip removal heat dissipation groove is in a spiral shape, chips can be discharged, the performance of the drill bit is improved, the service life of the drill bit is prolonged, a drill bit base protection mechanism reduces pressure and friction of a drill bit base through a protection telescopic column abrasion-resistant protection plate and the like, the drill bit base and a connecting pipe are sealed in a multi-layer mode through metal, rubber and a graphite sealing ring, and the sealing performance is ensured; the drill working efficiency is improved.

Description

Technical Field

[0001] The invention relates to the technical field of shale gas exploitation, and in particular to a directional PDC drill bit for shale gas exploitation. Background Art

[0002] Polycrystalline diamond composite drill bit, referred to as PDC drill bit, has a round composite piece welded on a cylindrical cutting tool, and the cutting tool is then mounted on the drill bit body. Since this drill bit was successfully manufactured and used in the early 1970s, it has developed rapidly. Compared with natural diamond drill bits, the cost of PDC drill bits has been greatly reduced, but it is only suitable for soft to medium-hard formations. In actual operations, PDC drill bits can use lower drilling pressure and higher rotation speed, can achieve high footage, and the unit footage cost is also lower. Moreover, the PDC drill bit system is cleverly designed. During installation, components such as the telescopic column work together and can be quickly replaced during maintenance, which greatly improves the convenience of operation and saves a lot of cost and time.

[0003] According to a highly efficient shockproof PDC drill bit disclosed on the patent website (authorization announcement number: CN216922028U), "This application discloses a highly efficient shockproof PDC drill bit, including a connecting rod, a conical disk is fixedly connected to the top of the connecting rod, a carcass is fixedly connected to the top of the conical disk, a plurality of crushing cutter heads are arranged on the top of the carcass, each crushing cutter head is composed of a fixed tool holder fixedly connected to the outer surface of the carcass and a plurality of crushing teeth fixedly connected to the outer surface of the fixed tool holder, a plurality of clearing blocks are arranged on the outer surface of the conical disk, each clearing block is composed of a convex block fixedly connected to the outer surface of the conical disk and a plurality of clearing convex bodies fixedly connected to the outer surface of the convex block, an outer ring is fixedly connected to the bottom of the carcass, and a gauge tooth is arranged on the outer surface of the outer ring. The vibration generated by the drill bit during drilling and recovery is reduced by arranging clearing blocks, conical disks and crushing convex bodies." Based on the above, the applicant believes that there are the following defects: The original PDC drill bit device has many defects. In terms of maintenance and replacement, there is no quick disassembly and assembly mechanism. The entire base needs to be disassembled to remove the PDC drill bit body, which is time-consuming and wastes resources. The replacement and maintenance efficiency is low, the sealing performance is poor, and there is no multi-layer sealing structure at the installation point of the base and the connecting pipe. Impurities are easy to enter and fluids are easy to leak. The seal is unstable under high temperature and high friction, and wear seriously affects work efficiency.

[0004] Therefore, it is necessary to design a directional PDC drill bit for shale gas extraction that is highly practical, easy to maintain and highly efficient. Summary of the invention

[0005] The object of the present invention is to provide a directional PDC drill bit for shale gas exploitation to solve the problems raised in the above background technology.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions: a directional PDC drill bit for shale gas exploitation, comprising a drill bit base, a PDC drill bit body is installed at the bottom end of the drill bit base, a drill bit connecting pipe is installed at the top of the drill bit base, a quick disassembly and assembly mechanism is arranged on the surface of the drill bit base, a tunneling mechanism is arranged on the surface of the PDC drill bit body, and a drill bit base protection mechanism is arranged on the surface of the drill bit base; The quick disassembly and assembly mechanism comprises a threaded connection seat, the threaded connection seat is fixedly connected to the top of the drill base, the bottom end of the drill connecting tube is provided with a connecting internal thread, a metal sealing ring is sleeved at the connection between the drill base and the drill connecting tube, a rubber sealing ring is sleeved at the connection between the drill base and the drill connecting tube, a graphite sealing ring is installed at the outer end of the rubber sealing ring, a fixing seat is fixedly connected to the bottom of the drill base, a clamping telescopic column is fixedly connected to the outer end of the fixing seat, an auxiliary spring is sleeved on the surface of the clamping telescopic column, a plug-in slot is provided at the bottom end of the drill base, an auxiliary plug-in interface is provided at the inner outer end of the plug-in slot, and the PDC drill bit The top of the PDC drill body is fixedly connected with a socket, and the surface of the socket is fixedly connected with an auxiliary limiting socket block, and an external fixing ring is installed between the drill bit base and the PDC drill bit body. The PDC drill bit body is clamped and limited by clamping the telescopic column and the auxiliary spring, and the socket is plugged into the plug slot, and the auxiliary limiting socket block is plugged into the auxiliary plug interface for installation. When the PDC drill bit body needs to be disassembled, the external fixing ring can be removed, and only the PDC drill bit body can be dismantled without disassembling the drill bit base, which can effectively reduce maintenance time, reduce waste of resources, and realize rapid replacement and repair.

[0007] According to the above technical solution, the drill bit base and the PDC drill bit body are threadedly connected by a threaded connection seat and a connecting internal thread, the rubber sealing ring is sleeved on the surface of the metal sealing ring, and the connection is sealed and protected by the metal sealing ring, the rubber sealing ring and the graphite sealing ring at the installation place of the drill bit base and the drill bit connecting pipe. The metal sealing ring uses the good pressure resistance and wear resistance of the metal to withstand greater pressure and prevent larger particles of impurities from entering the connection gap. The rubber sealing ring uses the high elasticity of the rubber to fill the tiny gap, enhance the sealing effect, and prevent fluid leakage; the outermost layer is provided with a layer of graphite sealing ring, which has good high temperature resistance and self-lubricating properties, and can maintain stable sealing performance in harsh environments of high temperature and high friction, while reducing the wear between the sealing rings and the connecting parts. These components ensure the sealing of the connection and ensure the efficiency of the drill bit when it is working.

[0008] According to the above technical solution, the plug socket is plugged into the plug slot, and the auxiliary limit plug block is plugged into the auxiliary plug interface.

[0009] According to the above technical solution, the outer ends of the clamping telescopic column and the auxiliary spring are in contact with the inner wall of the PDC drill bit body.

[0010] The higher the drilling speed, the lower the drilling speed, the faster the drilling speed will be, and the faster the drilling speed will be.PDC drill bit has a lot of advantages and disadvantages, so it is more suitable for drilling wells in drilling sites. The higher the drilling speed, the smaller the drilling speed will be, and the higher the drilling speed will be.PDC drill bit has a lot of advantages and disadvantages, so it is more cost-effective to drill wells in drilling sites.PDC drill bit has a lot of advantages and disadvantages, so it is more cost-effective to drill wells in drilling sites.PDC drill bit has a lot of advantages and disadvantages, so it is more cost-effective to drill wells in drilling sites.PDC drill bit has a lot of advantages and disadvantages, so it is more cost-effective to drill wells in drilling sites.PDC drill bit has a lot of advantages and disadvantages, so it is more cost-effective to drill wells in drilling sites.PDC drill bit has a lot of advantages and disadvantages, so it is more cost-effective to drill wells in drilling sites.PDC drill bit has a lot of advantages and disadvantages, so it is more cost-effective to drill wells in drilling sites

[0011] According to the above technical solution, the chip removal and heat dissipation grooves are opened between adjacent blades, and the chip removal and heat dissipation grooves are distributed in a spiral shape, and their depths gradually increase from the front end to the rear end of the PDC drill bit body.

[0012] According to the above technical solution, the drill base protection mechanism includes a connecting plate, which is fixedly connected to the left and right ends of the drill base, a protective telescopic column is fixedly connected to the surface of the connecting plate, a protective spring is sleeved on the surface of the protective telescopic column, a wear-resistant protective plate is fixedly connected to the outer end of the protective telescopic column, and a reinforcing plate is fixedly connected to the surface of the wear-resistant protective plate.

[0013] According to the above technical solution, the surface of the wear-resistant protective plate is coated with a tungsten carbide coating, and a wavy anti-slip structure is provided at its edge.

[0014] Compared with the prior art, the beneficial effects achieved by the present invention are: 1. The present invention is provided with a quick disassembly and assembly mechanism, and the PDC drill bit body is clamped and limited by clamping the telescopic column and the auxiliary spring. The plug-in seat is plugged into the plug-in slot, and the auxiliary limit plug-in block is plugged into the auxiliary plug-in interface to achieve installation. When the PDC drill bit body needs to be disassembled, the external fixing ring can be removed, and only the PDC drill bit body can be disassembled without disassembling the drill bit base, which can effectively reduce the maintenance time and reduce the waste of resources, and can also realize rapid replacement and repair.

[0015] 2. The present invention is provided with a tunneling mechanism. During the use of the device, tunneling operations are performed through the reinforced drill teeth on the surface of the blade. During the tunneling process, the rotating jet nozzle on the surface of the PDC drill bit body sprays drilling fluid. Through the special spiral guide groove design, the drilling fluid generates a high-speed rotating jet when it sprays out of the nozzle. Compared with the traditional direct injection hydraulic structure, the rotating jet can more efficiently crush the bottom rock of the well, especially in shale gas extraction, the impact and stripping effect on the rock is significantly enhanced. At the same time, it can also effectively clean the bottom rock cuttings to prevent the accumulation of rock cuttings from affecting drilling. The chip removal and heat dissipation groove can discharge the debris, ensure the smooth flow of drilling fluid, reduce the repeated crushing of rock cuttings, and improve the cutting performance and service life of the drill bit.

[0016] 3. The present invention is provided with a drill base protection mechanism. When the device is excavating, the durability of the drill base is directly related to the stability of the entire drilling operation. The system adopts a combination design of a protective telescopic column, a protective spring, a wear-resistant protective plate and a reinforcing plate. When the drill bit contacts the formation and generates pressure, the protective telescopic column can be flexibly extended and retracted, and cooperates with the buffering effect of the protective spring to effectively disperse the impact force. The wear-resistant protective plate can resist direct friction with the formation, and the reinforcing plate further enhances the structural strength. Such a design can not only reduce the pressure and friction on the drill base, but also adapt to the irregular shape of the formation surface during drilling, avoid excessive wear caused by local stress concentration, and extend the service life of the drill base.

[0017] 4. The present invention provides metal sealing rings, rubber sealing rings and graphite sealing rings to seal and protect the joints at the installation places of the drill base and the drill connecting pipe. The metal sealing rings use the good pressure resistance and wear resistance of metal to withstand greater pressure and prevent larger particle impurities from entering the connection gap. The rubber sealing ring uses the high elasticity of rubber to fill tiny gaps, enhance the sealing effect, and block fluid leakage. The outermost layer is further provided with a layer of graphite sealing rings, which have good high temperature resistance and self-lubricating properties, and can maintain stable sealing performance in harsh environments of high temperature and high friction, while reducing the wear between the sealing rings and the connecting parts. These components ensure the sealing of the joints and ensure the efficiency of the drill bit when it is working. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings: Figure 1 It is an overall schematic diagram of the present invention; Figure 2 is a schematic diagram of a PDC drill bit body of the present invention; Figure 3It is a schematic diagram of the quick disassembly and assembly mechanism of the present invention; Figure 4 1. It is a schematic diagram of a separated view of a PDC drill bit body of the present invention; Figure 5 It is a schematic diagram of the socket of the present invention; Figure 6 It is a schematic diagram of the drill base protection mechanism of the present invention.

[0019] In the figure: 1. drill base; 2. PDC drill body; 3. drill connecting pipe; 4. excavation mechanism; 41. blade; 42. reinforced drill teeth; 43. chip removal and heat dissipation groove; 44. installation port; 45. rotary jet nozzle; 5. drill base protection mechanism; 51. connecting plate; 52. protective telescopic column; 53. protective spring; 54. wear-resistant protective plate; 55. strengthening plate; 6. quick disassembly and assembly mechanism; 61. threaded connection seat; 62. connecting internal thread; 63. metal sealing ring; 64. rubber sealing ring; 65. graphite sealing ring; 66. fixing seat; 67. clamping telescopic column; 68. auxiliary spring; 69. plug-in slot; 601. auxiliary plug-in interface; 602. plug-in seat; 603. auxiliary limit plug-in block; 604. external fixing ring. DETAILED DESCRIPTION

[0020] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] The present invention provides the following technical solutions: Embodiment 1

[0022] See also Figure 1-6 The present invention provides a technical solution: a directional PDC drill bit for shale gas exploitation, comprising a drill bit base 1, a PDC drill bit body 2 is installed at the bottom of the drill bit base 1, a drill bit connecting pipe 3 is installed at the top of the drill bit base 1, a quick disassembly mechanism 6 is arranged on the surface of the drill bit base 1, the PDC drill bit body 2 and the drill bit connecting pipe 3, a tunneling mechanism 4 is arranged on the surface of the PDC drill bit body 2, and a drill bit base protection mechanism 5 is arranged on the surface of the drill bit base 1; The quick disassembly and assembly mechanism 6 includes a threaded connection seat 61, which is fixedly connected to the top of the drill base 1. The bottom end of the drill connecting tube 3 is provided with a connecting internal thread 62. A metal sealing ring 63 is sleeved at the connection between the drill base 1 and the drill connecting tube 3. A rubber sealing ring 64 is sleeved at the connection between the drill base 1 and the drill connecting tube 3. A graphite sealing ring 65 is installed at the outer end of the rubber sealing ring 64. A fixed seat 66 is fixedly connected to the bottom of the drill base 1. A clamping telescopic column 67 is fixedly connected to the outer end of the fixed seat 66. An auxiliary spring 68 is sleeved on the surface of the clamping telescopic column 67. A plug-in slot 69 is provided at the bottom of the drill base 1. An auxiliary plug-in interface 601 is provided at the outer end of the plug-in slot 69. The top of the PDC drill body 2 is fixedly connected to the drill base 1. A plug socket 602 is connected, and an auxiliary limit plug block 603 is fixedly connected to the surface of the plug socket 602. An external fixing ring 604 is installed between the drill bit base 1 and the PDC drill bit body 2. The PDC drill bit body 2 is clamped and limited by clamping the telescopic column 67 and the auxiliary spring 68. The plug socket 602 is plugged into the plug slot 69, and the auxiliary limit plug block 603 is plugged into the auxiliary plug interface 601 to achieve installation. When the PDC drill bit body 2 needs to be disassembled, the external fixing ring 604 can be removed, and only the PDC drill bit body 2 can be disassembled without disassembling the drill bit base 1, which can effectively reduce the maintenance time and reduce the waste of resources, and can also achieve rapid replacement and repair; The drill bit base 1 and the PDC drill bit body 2 are threadedly connected through a threaded connection seat 61 and a connecting internal thread 62. The rubber sealing ring 64 is sleeved on the surface of the metal sealing ring 63. The metal sealing ring 63, the rubber sealing ring 64 and the graphite sealing ring 65 are used to seal and protect the connection at the installation place of the drill bit base 1 and the drill bit connecting pipe 3. The metal sealing ring 63 uses the good pressure resistance and wear resistance of metal to withstand greater pressure and prevent larger particles of impurities from entering the connection gap. The rubber sealing ring 64 uses the high elasticity of rubber to fill the tiny gap, enhance the sealing effect, and prevent fluid leakage; the outermost layer is provided with a layer of graphite sealing ring, and the graphite sealing ring 65 has good high temperature resistance and self-lubricating properties, and can maintain stable sealing performance in a harsh environment of high temperature and high friction, while reducing the wear between the sealing rings and the connecting parts. These components ensure the sealing of the connection and the efficiency of the drill bit when it is working. The plug socket 602 is plugged into the plug slot 69, and the auxiliary limit plug block 603 is plugged into the auxiliary plug port 601; The outer ends of the clamping telescopic column 67 and the auxiliary spring 68 are in contact with the inner wall of the PDC drill bit body 2 . Embodiment 2

[0023] See also Figure 1-6On the basis of the first embodiment, the excavation mechanism 4 further comprises a blade wing 41, the blade wing 41 is fixedly connected to the surface of the PDC drill bit body 2, the reinforced drill teeth 42 are fixedly connected to the surface of the blade wing 41, the chip removal and heat dissipation groove 43 is opened on the surface of the PDC drill bit body 2, the surface of the PDC drill bit body 2 is provided with an installation port 44, and a rotating jet nozzle 45 is installed inside the installation port 44. During the use of the device, the excavation operation is performed through the reinforced drill teeth 42 on the surface of the blade wing 41. During the excavation process, the surface of the PDC drill bit body 2 rotates The jet nozzle 45 will spray the drilling fluid. Through the special spiral guide groove design, the drilling fluid will generate a high-speed rotating jet when it is ejected from the nozzle. Compared with the traditional direct injection hydraulic structure, the rotating jet can more efficiently break the bottom rock of the well, especially in shale gas mining, the impact and stripping effect on the rock is significantly enhanced. At the same time, it can also effectively clean the bottom rock cuttings to prevent the accumulation of rock cuttings from affecting drilling. The chip removal and heat dissipation groove 43 can discharge the debris, ensure the smooth flow of drilling fluid, reduce the repeated crushing of rock cuttings, and improve the cutting performance and service life of the drill bit; The chip removal and heat dissipation grooves 43 are arranged between adjacent blades 41, and the chip removal and heat dissipation grooves 43 are distributed in a spiral shape, and the depth thereof gradually increases from the front end to the rear end of the PDC drill bit body 2; The drill bit base protection mechanism 5 includes a connecting plate 51, which is fixedly connected to the left and right ends of the drill bit base 1. A protective telescopic column 52 is fixedly connected to the surface of the connecting plate 51. A protective spring 53 is sleeved on the surface of the protective telescopic column 52. A wear-resistant protective plate 54 is fixedly connected to the outer end of the protective telescopic column 52. A reinforcing plate 55 is fixedly connected to the surface of the wear-resistant protective plate 54. During the excavation process of the device, the drill bit base 1 can reduce the pressure on the drill bit base 1 through the coordinated use of the protective telescopic column 52, the protective spring 53, the wear-resistant protective plate 54 and the reinforcing plate 55, reduce the friction on the drill bit base 1, can better fit the irregular shape of the formation surface during the drilling process, and reduce the wear caused by local stress concentration; The surface of the wear-resistant protective plate 54 is coated with a tungsten carbide coating, and a wave-shaped anti-slip structure is provided at its edge.

[0024] In actual operation, when the device is used, the PDC drill bit body 2 is clamped and limited by clamping the telescopic column 67 and the auxiliary spring 68, and the plug seat 602 is plugged into the plug slot 69, and the auxiliary limit plug block 603 is plugged into the auxiliary plug interface 601 to achieve installation. When the PDC drill bit body 2 needs to be disassembled, the external fixing ring 604 is removed, and only the PDC drill bit body 2 can be disassembled without disassembling the drill bit base 1, which can effectively reduce the maintenance time and reduce the waste of resources, and can also achieve rapid replacement and maintenance; At the installation place of the drill base 1 and the drill connecting pipe 3, the connection is sealed and protected by a metal sealing ring 63, a rubber sealing ring 64 and a graphite sealing ring 65. The metal sealing ring 63 uses the good pressure resistance and wear resistance of metal to withstand greater pressure and prevent larger particles of impurities from entering the connection gap. The rubber sealing ring 64 uses the high elasticity of rubber to fill the tiny gap to enhance the sealing effect and prevent fluid leakage. The outermost layer is provided with a layer of graphite sealing ring. The graphite sealing ring 65 has good high temperature resistance and self-lubricating properties, and can maintain stable sealing performance in a harsh environment of high temperature and high friction, while reducing the wear between the sealing rings and the connecting parts. Through these components, the sealing of the connection is guaranteed, and the efficiency of the drill bit during operation is guaranteed; During the use of the device, the excavation operation is performed through the reinforced drill teeth 42 on the surface of the blade 41. During the excavation process, the rotating jet nozzle 45 on the surface of the PDC drill bit body 2 will spray the drilling fluid. Through the special spiral guide groove design, the drilling fluid generates a high-speed rotating jet when it sprays out of the nozzle. Compared with the traditional direct injection hydraulic structure, the rotating jet can more efficiently break the bottom rock of the well, especially in shale gas extraction, the impact and stripping effect on the rock is significantly enhanced. At the same time, it can also effectively clean the bottom rock cuttings to prevent the accumulation of rock cuttings from affecting drilling. The chip heat dissipation groove 43 can discharge the debris, ensure the smooth flow of drilling fluid, reduce the repeated crushing of rock cuttings, and improve the cutting performance and service life of the drill bit; During the excavation process of the device, the drill base 1 will reduce the pressure on the drill base 1 and the friction on the drill base 1 through the coordinated use of the protective telescopic column 52, the protective spring 53, the wear-resistant protective plate 54 and the reinforcing plate 55, so that it can better fit the irregular shape of the formation surface during the drilling process and reduce the wear caused by local stress concentration.

[0025] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0026] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A directional PDC drill bit for shale gas extraction, comprising a drill bit base (1), characterized in that: A PDC drill bit body (2) is installed at the bottom end of the drill bit base (1), a drill bit connecting pipe (3) is installed at the top of the drill bit base (1), a quick disassembly mechanism (6) is provided on the surfaces of the drill bit base (1), the PDC drill bit body (2) and the drill bit connecting pipe (3), a tunneling mechanism (4) is provided on the surface of the PDC drill bit body (2), and a drill bit base protection mechanism (5) is provided on the surface of the drill bit base (1); The quick disassembly and assembly mechanism (6) comprises a threaded connection seat (61), the threaded connection seat (61) is fixedly connected to the top of the drill base (1), the bottom end of the drill connecting tube (3) is provided with a connecting internal thread (62), a metal sealing ring (63) is sleeved at the connection between the drill base (1) and the drill connecting tube (3), a rubber sealing ring (64) is sleeved at the connection between the drill base (1) and the drill connecting tube (3), a graphite sealing ring (65) is installed at the outer end of the rubber sealing ring (64), and a fixing seat (66) is fixedly connected to the bottom of the drill base (1). The outer end of the fixing seat (66) is fixedly connected to a clamping telescopic column (67), the surface of the clamping telescopic column (67) is sleeved with an auxiliary spring (68), the bottom end of the drill bit base (1) is provided with a plug-in slot (69), the inner outer end of the plug-in slot (69) is provided with an auxiliary plug-in interface (601), the top of the PDC drill bit body (2) is fixedly connected to a plug-in seat (602), the surface of the plug-in seat (602) is fixedly connected to an auxiliary limit plug-in block (603), and an external fixing ring (604) is installed between the drill bit base (1) and the PDC drill bit body (2).

2. A directional PDC drill bit for shale gas extraction according to claim 1, characterized in that: The drill bit base (1) and the PDC drill bit body (2) are threadedly connected via a threaded connection seat (61) and a connecting internal thread (62), and the rubber sealing ring (64) is sleeved on the surface of the metal sealing ring (63).

3. A directional PDC drill bit for shale gas extraction according to claim 2, characterized in that: The plug socket (602) is plugged into the plug slot (69), and the auxiliary limit plug block (603) is plugged into the auxiliary plug interface (601).

4. A directional PDC drill bit for shale gas extraction according to claim 3, characterized in that: The outer ends of the clamping telescopic column (67) and the auxiliary spring (68) are in contact with the inner wall of the PDC drill bit body (2).

5. A directional PDC drill bit for shale gas extraction according to claim 4, characterized in that: The excavation mechanism (4) comprises a blade (41), the blade (41) being fixedly connected to the surface of a PDC drill bit body (2), the reinforced drill teeth (42) being fixedly connected to the surface of the blade (41), the chip removal and heat dissipation groove (43) being provided on the surface of the PDC drill bit body (2), the surface of the PDC drill bit body (2) being provided with a mounting opening (44), and a rotating jet nozzle (45) being installed inside the mounting opening (44).

6. A directional PDC drill bit for shale gas extraction according to claim 5, characterized in that: The chip removal and heat dissipation grooves (43) are arranged between adjacent blades (41), and the chip removal and heat dissipation grooves (43) are distributed in a spiral shape, with the depth gradually increasing from the front end to the rear end of the PDC drill bit body (2).

7. A directional PDC drill bit for shale gas extraction according to claim 6, characterized in that: The drill base protection mechanism (5) comprises a connecting plate (51), the connecting plate (51) being fixedly connected to the left and right ends of the drill base (1), a protective telescopic column (52) being fixedly connected to the surface of the connecting plate (51), a protective spring (53) being sleeved on the surface of the protective telescopic column (52), a wear-resistant protective plate (54) being fixedly connected to the outer end of the protective telescopic column (52), and a reinforcing plate (55) being fixedly connected to the surface of the wear-resistant protective plate (54).

8. A directional PDC drill bit for shale gas extraction according to claim 7, characterized in that: The surface of the wear-resistant protective plate (54) is coated with a tungsten carbide coating, and a wave-shaped anti-slip structure is provided on its edge.

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