A shale gas exploitation drilling rig using a self-lubricating drill bit

Abstract

This invention relates to the field of drill bit technology, specifically to a self-lubricating drill bit for shale gas extraction, comprising a toothed mechanism, three sets of clamping mechanisms, and three sets of roller cone mechanisms installed within the toothed mechanism. By installing three evenly distributed sets of clamping mechanisms within the toothed mechanism, and movably mounting the roller cone mechanisms within these mechanisms, the drill bit rotates at high speed as the external drilling equipment drives the spindle. The three evenly distributed roller cone mechanisms then efficiently drill deep into the strata. As the drill bit generates high temperatures due to high-speed rotation, the oil in the upper half of the reservoir expands rapidly due to the heat, forcing the lubricating oil in the lower half of the reservoir towards the bearing system and roller cone mechanisms. This effectively increases the amount of lubricating oil injected into the bearing system and roller cone mechanisms, thereby reducing the problem of shortened bearing life caused by reduced inherent lubricating oil, and effectively improving the lifespan and practicality of the drill bit.

Description

Technical Field

[0001] This invention relates to the field of drill bit technology, specifically to a self-lubricating drill bit for shale gas development. Background Technology

[0002] The drill bit used in shale gas extraction is a roller cone bit, which is a core rock-breaking tool used in oil drilling, geological exploration and mining. Through the coordinated work of its three rotating roller cones, it can efficiently break underground rocks and is widely used in various formations such as soft, medium and hard.

[0003] Existing roller cone drill bits mainly consist of four parts: the drill bit body, three roller cones, a bearing system, and a nozzle. During operation, under the action of drilling pressure and rotation, the roller cones roll at the bottom of the well, generating three types of combined rock-breaking action.

[0004] However, the internal teeth pre-installed on the roller cone will be worn by deep rocks under long-term high temperature and high pressure conditions, which will cause problems such as breakage and chipping of the internal teeth due to wear. In severe cases, the pressure roller rotates at high speed along the bearing system inside the tooth. The inherent amount of lubricating oil inside the bearing system will tend to dry out due to high-speed rotation or compression. Once the inherent amount of lubricating oil is reduced, the wear of the bearing system will also be aggravated, which will affect the performance of the roller cone drill bit.

[0005] In view of this, a self-lubricating drill bit for shale gas development was designed to solve the above problems. Summary of the Invention

[0006] The present invention aims to solve one of the technical problems existing in the prior art or related technologies.

[0007] Therefore, the technical solution adopted in this invention is as follows: A self-lubricating drill bit for shale gas extraction includes a toothed mechanism, three sets of clamping mechanisms and three sets of roller cone mechanisms installed within the toothed mechanism, with the roller cone mechanisms movably installed within the clamping mechanisms. The toothed mechanism includes an assembly head with a connector mounted on its outer end, and a liquid reservoir fixedly installed inside the assembly head, the liquid reservoir having three guide pipes. The clamping mechanisms include a rotating bushing installed within the assembly head, with two bushings installed within the rotating bushing, and multiple bearings movably installed between the two bushings. The gear mechanism includes a shaft movably mounted within a rotating bushing and passing through multiple bearing balls. A fixing block and a shaft are mounted on the outside of the shaft. A pressure-resistant main shell and multiple pressure-resistant secondary shells are mounted on the outside of the fixing block. A sliding sleeve is movably mounted on the outside of the shaft, and a pressure-boosting slider is mounted on the outside of the sliding sleeve. Multiple evenly distributed support plates are provided on the outside of the sliding sleeve. Two protective pads are mounted on the support plates, and multiple inner teeth are provided in the two protective pads. The inner teeth are adapted to extend through to the outside of the pressure-resistant secondary shells.

[0008] In a preferred embodiment, the present invention can be further configured such that: three grooves are provided inside the assembly head, a sealing strip is installed in the grooves, and a vertical hole communicating with the inner cavity of the connector is provided in the middle of the assembly head; A through hole is provided at the bottom of the inner side of the groove.

[0009] In a preferred embodiment, the present invention can be further configured as follows: a plug is threadedly installed on the pipe section on the outer wall of the liquid storage tank, a gasket is movably installed inside the liquid storage tank, and an annular groove is formed on the outer wall of the gasket, with a rubber ring sleeved inside the annular groove; The upper half of the cavity of the liquid reservoir and the plug is filled with oil, and the lower half of the cavity of the liquid reservoir and the plug is filled with lubricating oil.

[0010] In a preferred embodiment, the present invention can be further configured such that: three transfer cylinders are fixedly installed at the bottom of the inner cavity of the liquid storage tank, the inner wall of the transfer cylinder has multiple oil grooves, and a plug and a first spring are provided inside the transfer cylinder, the top end of the first spring being adapted to bear pressure on the plug.

[0011] In a preferred embodiment, the present invention can be further configured such that: the interior of the rotating bushing is provided with an oil inlet hole and a screw hole, and a reciprocating screw is adapted to be installed in the screw hole. The rod end of the reciprocating screw that penetrates into the inner cavity of the rotating bushing has a T-shaped structure, and the T-shaped end is adapted to bear pressure on the sliding sleeve.

[0012] In a preferred embodiment, the present invention may be further configured such that: a built-in protective pad is provided in the middle of the inner cavity of the rotating bushing, and the built-in protective pad is movably installed inside the multiple bearing balls, and the shaft is installed inside the built-in protective pad.

[0013] In a preferred embodiment, the present invention can be further configured as follows: the outer wall of the shaft is provided with a plurality of evenly distributed guide grooves, and the tapered end of the shaft extending through to the outside of the pressure-resistant main shell is provided with an annular groove; the outer wall of the pressure-boosting slider is provided with a plurality of fan-shaped grooves, and the support plate is adapted to be snapped into the fan-shaped grooves. After closing, the annular port adapters of the main pressure-resistant shell and multiple secondary pressure-resistant shells are fitted into the annular groove.

[0014] In a preferred embodiment, the present invention can be further configured such that: a pressure-bearing ring is installed on the outside of the shaft, the pressure-bearing ring has a plurality of evenly distributed annular holes, the inner wall of the support plate is provided with a support rod, and the other end of the support rod is adapted to pass through the annular hole.

[0015] In a preferred embodiment, the present invention can be further configured such that: the protective pad has a slot at one end facing the fixing block, the fixing block is provided with multiple sets of limiting plates, two adjacent limiting plates are used to provide limiting constraints for the extension of the support plate, and two adjacent slots facilitate the quick loading and unloading of the inner teeth.

[0016] In a preferred embodiment, the present invention can be further configured such that: two second springs are symmetrically distributed between the support plate and the pressure-resistant sub-shell; the pressure-resistant sub-shell has multiple holes inside; and the T-shaped rod segment inside the inner toothed section is adapted to penetrate into the holes inside the pressure-resistant sub-shell.

[0017] By adopting the above technical solution, the beneficial effects achieved by the present invention are as follows: 1. This invention installs three evenly distributed clamping mechanisms within the toothed mechanism, and movably installs roller cone mechanisms within these clamping mechanisms. With the external drilling equipment driving the spindle and causing the drill bit to rotate at high speed, the three evenly distributed roller cone mechanisms can efficiently drill deep into the interior. As the drill bit generates high temperatures due to high-speed rotation, the oil in the upper half of the reservoir expands rapidly due to the heat, forcing the lubricating oil in the lower half of the reservoir into the bearing system and roller cone mechanisms. This effectively increases the amount of lubricating oil injected into the bearing system and roller cone mechanisms, thereby reducing the problem of shortened bearing life caused by reduced inherent lubricating oil, and effectively improving the lifespan and practicality of the drill bit.

[0018] 2. This invention utilizes a socket wrench to sequentially rotate three reciprocating lead screws. The sliding sleeve and the pressure-boosting slider, which are ultimately pressed by the reciprocating lead screws, will compress multiple evenly distributed support plates. The multiple evenly distributed inner teeth can extend outwards at a constant length, thereby making efficient use of the inherent length of the inner teeth and reducing the cost of replacing them after wear.

[0019] 3. This invention sets the roller mechanism as an assembly structure and assembles a pressure-resistant main shell and multiple pressure-resistant secondary shells on the outside of the fixed block. The pressure-resistant secondary shells provide a support carrier for multiple inner teeth. When the inner teeth are completely damaged, the pressure-resistant main shell and pressure-resistant secondary shells can be disassembled and the inner teeth replaced by welding, thereby effectively reducing the subsequent maintenance cost of the drill bit. Attached Figure Description

[0020] Figure 1 This is a schematic diagram illustrating the use of the present invention; Figure 2 This is a bottom view diagram of the present invention; Figure 3 This is a schematic diagram of the drill bit mechanism of the present invention; Figure 4 This is a cross-sectional schematic diagram of the liquid storage cover of the present invention; Figure 5 For the present invention Figure 4 Enlarged view of point A in the middle; Figure 6 For the present invention Figure 1 A partial schematic diagram; Figure 7 For the present invention Figure 6 An explosion diagram; Figure 8 This is an exploded view of the clamping mechanism of the present invention; Figure 9 This is a schematic diagram of the toothed wheel mechanism of the present invention; Figure 10 For the present invention Figure 9 An explosion diagram; Figure 11 For the present invention Figure 10 A partial schematic diagram.

[0021] Figure label: 100. Toothed mechanism; 110. Connector; 120. Assembly head; 1201. Groove; 130. Sealing strip; 140. Liquid reservoir; 1401. Plug; 1402. Guide tube; 150. Gasket; 1501. Rubber ring; 160. Transfer cylinder; 1601. Oil tank; 170. Plug; 180. First spring; 200 Clamping mechanism; 210 Rotary bushing; 2101 Oil inlet; 2102 Threaded hole; 220 Reciprocating lead screw; 230 Shaft washer; 240 Internal protective washer; 250 Bearing ball; 300. Gear mechanism; 310. Fixing block; 3101. Limiting plate; 320. Pressure-resistant main shell; 330. Pressure-resistant secondary shell; 340. Shaft; 3401. Guide groove; 3402. Annular groove; 350. Sliding sleeve; 3501. Pressure-boosting slider; 3502. Fan-shaped groove; 360. Pressure-bearing ring; 3601. Annular hole; 370. Support plate; 3701. Support rod; 3702. Protective pad; 3703. Slot; 380. Internal gear; 390. Second spring. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other.

[0023] It should be understood that these descriptions are merely exemplary and are not intended to limit the scope of the invention.

[0024] The following describes, with reference to the accompanying drawings, some embodiments of the present invention, providing a self-lubricating drill bit for shale gas extraction.

[0025] Example 1: Combination Figures 1 to 11As shown, the present invention provides a self-lubricating drill bit for shale gas extraction, comprising a toothed mechanism 100, three sets of clamping mechanisms 200 and three sets of roller cone mechanisms 300 installed within the toothed mechanism 100, and the roller cone mechanisms 300 being movably installed within the clamping mechanisms 200. The toothed mechanism 100 provides an effective assembly carrier for the three sets of clamping mechanisms 200 and the three sets of roller cone mechanisms 300, facilitating self-lubricating protection for the clamping mechanisms 200 and the roller cone mechanisms 300. The clamping mechanisms 200, in conjunction with the injected lubricating oil, further enhance the wear protection of the roller cone mechanisms 300. The roller cone mechanisms 300 facilitate improving the utilization rate of the internal tooth arrangement, further enhancing the service life of the drill bit.

[0026] The tooth mechanism 100 includes an assembly head 120, a connector 110 is installed at the outer end of the assembly head 120, and a liquid reservoir 140 is fixedly installed inside the assembly head 120. The liquid reservoir 140 is provided with three guide tubes 1402. Three grooves 1201 are opened inside the assembly head 120. A sealing strip 130 is installed in the grooves 1201. A vertical hole communicating with the inner cavity of the connector 110 is opened in the middle of the assembly head 120. A through hole is provided at the bottom of the inner side of the groove 1201. A plug 1401 is threaded on the pipe section of the outer wall of the liquid storage cover 140. A gasket 150 is movably installed inside the liquid storage cover 140. An annular groove is provided on the outer wall of the gasket 150, and a rubber ring 1501 is sleeved in the annular groove. The upper half cavity of the liquid storage cover 140 and the gasket 150 is filled with oil, and the lower half cavity of the liquid storage cover 140 and the gasket 150 is filled with lubricating oil. Three transfer cylinders 160 are fixedly installed at the bottom of the inner cavity of the liquid storage tank 140. Multiple oil grooves 1601 are opened on the inner wall of the transfer cylinder 160. A plug 170 and a first spring 180 are provided inside the transfer cylinder 160. The top of the first spring 180 is adapted to bear pressure on the plug 170. The clamping mechanism 200 includes a rotating bushing 210 installed in the assembly head 120, and two bushings 230 are installed inside the rotating bushing 210. Multiple bearing balls 250 are movably installed between the two bushings 230. The rotating bushing 210 has an oil inlet hole 2101 and a screw hole 2102 inside. A reciprocating screw 220 is adapted to be installed in the screw hole 2102. The rod end of the reciprocating screw 220 that passes through the inner cavity of the rotating bushing 210 has a T-shaped structure. An internal protective pad 240 is provided in the middle of the inner cavity of the rotating bushing 210, and the internal protective pad 240 is movably installed inside the multiple bearing balls 250. The gear mechanism 300 includes a shaft 340 movably installed inside a rotating bushing 210 and passing through multiple bearing balls 250. A fixing block 310 and the shaft 340 are installed outside the shaft 340. A pressure-resistant main shell 320 and multiple pressure-resistant secondary shells 330 are installed outside the fixing block 310. A sliding sleeve 350 is movably installed outside the shaft 340, and a pressure-boosting slider 3501 is installed outside the sliding sleeve 350. Multiple evenly distributed support plates 370 are provided outside the sliding sleeve 350. Two protective pads 3702 are installed on the support plates 370, and multiple internal teeth 380 are provided inside the two protective pads 3702. The internal teeth 380 are adapted to penetrate to the outside of the pressure-resistant secondary shell 330. The shaft 340 is installed inside the built-in pad 240, and the T-shaped end is adapted to bear pressure on the sleeve 350.

[0027] Preferably, after the inner cavity of the connector 110 is connected to the middle hole of the assembly head 120, a high-pressure aqueous solution can be sprayed from the middle vertical hole of the assembly head 120 into the gap of the three sets of roller cone mechanisms 300 using an external injection device. At this time, the three sets of roller cone mechanisms 300 can cooperate with the aqueous solution to perform efficient drilling operations on deep rocks. The pipe section on the outer wall of the liquid reservoir 140 is adapted to pass through one of the grooves 1201, which facilitates the replacement of the oil in the upper cavity of the liquid reservoir 140 and the plug 150. This avoids the oil from deteriorating due to long-term use and high temperature, which would affect the smoothness of the plug 150 and the rubber ring 1501 sliding back and forth along the inner cavity of the liquid reservoir 140. When the drill bit drills into the deep rock and generates high temperature, the oil in the upper cavity expands due to the high temperature, which will squeeze the plug 150 and rubber ring 1501 to slide towards the lower cavity. The lubricating oil stored in the lower cavity will be squeezed and enter along the top port of the transfer cylinder 160. The plug 170 will be pressed down. Finally, the lubricating oil will be quickly transferred along multiple oil grooves 1601 and guide pipes 1402. Finally, the lubricating oil can be input into the rotating bushing 210 and the gear mechanism 300. This will improve the high oil volume protection of the bearing system inside the rotating bushing 210, and at the same time, it can avoid the problem of wear caused by the movement of the internal components of the gear mechanism 300 due to high temperature. In addition, the hexagonal end of the reciprocating lead screw 220 is adapted to penetrate into the groove 1201, which facilitates convenient adjustment of the outward extension of the inner tooth 380 after wear. The built-in protective pads 240 set inside the multiple bearing balls 250 are used to enhance the stability and protection of the transverse rear shaft 340. Among them, the bearing ring 360, shaft 340 and pressure-boosting slider 3501 have the same diameter and width, and the inner wall of the pressure-boosting slider 3501 has a smooth coating structure. After the reciprocating screw 220 moves laterally and pushes the sliding sleeve 350, the pressurized pressure-boosting slider 3501 can slide smoothly along the outside of the shaft 340. With the help of multiple sets of limiting plates 3101 and multiple fan-shaped grooves 3502, the constant distance between the reciprocating extension of multiple support plates 370 can be improved, effectively ensuring that the length of multiple inner teeth 380 extending out of multiple pressure-resistant subshells 330 remains consistent, which facilitates efficient drilling of deep rocks.

[0028] Example 2: Combination Figures 8 to 11 As shown, based on Embodiment 1, the outer wall of the shaft 340 is provided with a plurality of evenly distributed guide grooves 3401, and the tapered end of the shaft 340 that extends through to the outside of the pressure-resistant main shell 320 is provided with an annular groove 3402. The outer wall of the pressure-boosting slider 3501 is provided with a plurality of fan-shaped grooves 3502, and the support plate 370 is adapted to be snapped into the fan-shaped grooves 3502. After closing, the annular port adapters of the main pressure-resistant shell 320 and multiple secondary pressure-resistant shells 330 are fitted into the annular groove 3402; A bearing ring 360 is installed on the outside of the shaft 340. The bearing ring 360 has multiple evenly distributed annular holes 3601. The inner wall of the support plate 370 is provided with a support rod 3701, and the other end of the support rod 3701 is adapted to pass through the annular hole 3601.

[0029] Preferably, the outer surface of the support plate 370 has a smooth coating structure. Two adjacent protective pads 3702 are welded to the outer surface of the support plate 370. After the evenly distributed multiple inner teeth 380 are inserted into the gap between the two protective pads 3702 through the two slots 3703, the multiple inner teeth 380 can be pre-fixed to the outer wall of the support plate 370 by adhesive. After the plate end of the support plate 370 facing the fixing block 310 is adapted to be snapped into the inside of the fan-shaped groove 3502, the support rod 3701 located on the inner wall of the support plate 370 is inserted into the annular hole 3601 to obtain further stabilization and support. When the end of the inner tooth 380 that extends to the outside of the pressure-resistant sub-shell 330 is subjected to long-term rotation under high temperature and high pressure and wears out, in order to further improve the utilization rate of the inner tooth 380, the three reciprocating screws 220 can be rotated by a socket wrench until the reciprocating screws 220 extend into the inner cavity of the rotating bushing 210 through the screw hole 2102. Finally, the sliding sleeve 350 and the pressure-boosting slider 3501 will be pressed and squeeze the evenly distributed multiple support plates 370 outward, and the evenly distributed multiple inner teeth 380 can be further squeezed outward, which is conducive to improving the utilization rate of the inner tooth 380 with inherent length.

[0030] Example 3: Combination Figures 9 to 11 As shown, in the above embodiment, the protective pad 3702 has a slot 3703 at one end facing the fixing block 310, and the fixing block 310 is provided with multiple sets of limiting plates 3101. Two adjacent limiting plates 3101 are used to provide limiting constraints for the extension of the support plate 370, and two adjacent slots 3703 facilitate the quick loading and unloading of the inner teeth 380. Two second springs 390 are symmetrically distributed between the support plate 370 and the pressure-resistant sub-shell 330. The pressure-resistant sub-shell 330 has multiple holes inside, and the T-shaped rod segment inside the inner toothed rack 380 is adapted to pass through the holes inside the pressure-resistant sub-shell 330.

[0031] Preferably, the protruding tube section after the pressure-resistant main shell 320 and multiple pressure-resistant secondary shells 330 are closed is adapted to pass through the port of the rotating bushing 210, and the gap after the pressure-resistant main shell 320 and multiple pressure-resistant secondary shells 330 are closed can be fixed by welding, which facilitates providing sufficient stable support and pressure protection for the evenly distributed multiple inner teeth 380. Among them, the two second springs 390 located on the support plate 370 are pressed against the inner side of the pressure-resistant sub-shell 330, which facilitates the compression and pressure-boosting slider 3501 to apply centered pressure to the support plate 370 towards the shaft 340. The evenly distributed support plates 370 will quickly reset under pressure, which facilitates the provision of an effective assembly carrier for the subsequent replacement of the inner gear 380. The support plates 370 can slide smoothly and safely along the gap between the two adjacent limit plates 3101, further enhancing the drilling efficiency of the multiple support plates 370 and the multiple inner gears 380 in the fixed state.

[0032] The working principle and usage process of this invention are as follows: When the toothed mechanism 100 is installed on the spindle section of the external drilling equipment, the external drilling equipment controls the spindle to rotate and drives the toothed mechanism 100, the clamping mechanism 200 and the toothed cone mechanism 300 to rotate at high speed. As the spindle is pressed, the drill bit is driven to drill into the deep layer. The three sets of toothed cone mechanisms 300 rotating at high speed will effectively drill into the deep layer. As the ambient temperature of the drilling equipment rises and the drill bit overheats due to friction while drilling deep, the high temperature generated by the drill bit will first radiate to the assembly head 120. The heat energy then passes through the assembly head 120 and acts on the reservoir 140. The oil injected through the external pipe section of the reservoir 140 expands under the high temperature, causing the oil in the upper half of the reservoir 140 and the gasket 150 to expand. The pressurized gasket 150 and rubber ring 1501 will slide downwards, and the pre-... The lubricating oil stored in the lower half of the cavity of the plug 150 and the reservoir 140 is squeezed and flows into the three clamping mechanisms 200 through the three guide pipes 1402. The lubricating oil will enter the hole in the inner cavity of the rotating sleeve 210 through the oil inlet hole 2101. Finally, the lubricating oil will flow into the gear mechanism 300 through the hole in the middle of the rotating sleeve 210. This process may cause the bearing balls 250 to rotate due to the high temperature of the drill bit, resulting in increased resistance. By increasing the amount of lubricating oil filling the sealed cavity of the bearing balls 250 and the gear mechanism 300, the smoothness of the gear mechanism 300 rotation under high temperature and pressure can be improved, effectively reducing the problem of increased lubricating oil loss caused by high temperature and increased speed, which in turn leads to increased bearing wear and affects the service life of the drill bit. Meanwhile, as the wear on the outer ends of the evenly distributed internal teeth 380 increases, in order to improve the service life of the drill bit, the three sealing strips 130 are removed from the three grooves 1201, and the reciprocating screws 220 are rotated with the help of a socket wrench. The three reciprocating screws 220 are assisted in rotating and apply a lateral thrust to the three sliding sleeves 350. As the sliding sleeves 350 drive the pressure boosting slider 3501 to move laterally along the outside of the shaft 340, the pressure boosting slider 3501 will push the evenly distributed support plates 37 0. A constant compressive force is applied, and eventually, multiple evenly distributed support plates 370, together with multiple sets of protective pads 3702, extrude multiple inner teeth 380 outward. At this time, the evenly distributed multiple inner teeth 380 can extend outward toward the outside of the pressure-resistant main shell 320 and the pressure-resistant secondary shell 330. This process can further make efficient use of the constant length inner teeth 380, thereby effectively improving the service life of the gear mechanism 300 and further reducing the cost of replacing the entire drill bit due to wear of the inner teeth 380.

[0033] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A self-lubricating drill bit for shale gas extraction, comprising a tooth-handling mechanism (100), characterized in that, It also includes three sets of clamping mechanisms (200) and three sets of toothed wheel mechanisms (300) installed in the toothed wheel mechanism (100), and the toothed wheel mechanism (300) is movably installed in the clamping mechanism (200); The tooth and palm mechanism (100) includes an assembly head (120), a connector (110) is installed at the outer end of the assembly head (120), and a liquid reservoir (140) is fixedly installed inside the assembly head (120). Three guide tubes (1402) are provided on the liquid reservoir (140). The clamping mechanism (200) includes a rotating bushing (210) installed in the assembly head (120), and two bushings (230) are installed in the rotating bushing (210), and a plurality of bearing balls (250) are movably installed between the two bushings (230). The gear mechanism (300) includes a shaft (340) movably mounted inside a rotating bushing (210) and passing through multiple bearing balls (250). A fixing block (310) and a shaft (340) are mounted on the outside of the shaft (340). A pressure-resistant main shell (320) and multiple pressure-resistant secondary shells (330) are mounted on the outside of the fixing block (310). A sliding sleeve (350) is movably mounted on the outside of the shaft (340), and a pressure-boosting slider (3501) is mounted on the outside of the sliding sleeve (350). Multiple evenly distributed support plates (370) are provided on the outside of the sliding sleeve (350). Two protective pads (3702) are mounted on the support plates (370), and multiple internal teeth (380) are provided in the two protective pads (3702). The internal teeth (380) are adapted to penetrate to the outside of the pressure-resistant secondary shell (330).

2. The shale gas extraction drilling tool with a self-lubricating drill bit according to claim 1, characterized in that, The assembly head (120) has three grooves (1201) inside, and a sealing strip (130) is installed in the groove (1201). The assembly head (120) has a vertical hole in the middle that communicates with the inner cavity of the connector (110). A through hole is provided at the bottom of the inner side of the groove (1201).

3. The shale gas extraction drilling tool with a self-lubricating drill bit according to claim 1, characterized in that, A plug (1401) is threaded onto the pipe section on the outer wall of the liquid storage cover (140). A gasket (150) is movably installed inside the liquid storage cover (140). An annular groove is formed on the outer wall of the gasket (150), and a rubber ring (1501) is fitted inside the annular groove. The upper half of the cavity of the liquid reservoir (140) and the plug (150) is filled with oil, and the lower half of the cavity of the liquid reservoir (140) and the plug (150) is filled with lubricating oil.

4. The shale gas extraction drilling tool with a self-lubricating drill bit according to claim 1, characterized in that, Three transfer cylinders (160) are fixedly installed at the bottom of the inner cavity of the liquid storage cover (140). Multiple oil grooves (1601) are opened on the inner wall of the transfer cylinder (160), and a plug (170) and a first spring (180) are provided inside the transfer cylinder (160). The top of the first spring (180) is adapted to bear pressure on the plug (170).

5. A shale gas extraction drilling tool with a self-lubricating drill bit according to claim 1, characterized in that, The rotating bushing (210) has an oil inlet hole (2101) and a screw hole (2102) inside. A reciprocating screw (220) is adapted to be installed in the screw hole (2102). The end of the reciprocating screw (220) that passes through the inner cavity of the rotating bushing (210) is T-shaped and is adapted to be pressed on the sliding sleeve (350).

6. The shale gas extraction drilling tool with a self-lubricating drill bit according to claim 1, characterized in that, The inner cavity of the rotating bushing (210) is provided with a built-in protective pad (240), and the built-in protective pad (240) is movably installed inside multiple bearing balls (250), and the shaft (340) is installed inside the built-in protective pad (240).

7. A shale gas extraction drilling tool with a self-lubricating drill bit according to claim 1, characterized in that, The outer wall of the shaft (340) is provided with a plurality of evenly distributed guide grooves (3401), and the tapered end of the shaft (340) that extends through to the outside of the pressure-resistant main shell (320) is provided with an annular groove (3402). The outer wall of the pressure-boosting slider (3501) is provided with a plurality of fan-shaped grooves (3502), and the support plate (370) is adapted to be snapped into the fan-shaped grooves (3502). After closing, the annular port adapters of the main pressure-resistant shell (320) and multiple secondary pressure-resistant shells (330) are fitted into the annular groove (3402).

8. The shale gas extraction drilling tool with a self-lubricating drill bit according to claim 1, characterized in that, A pressure ring (360) is installed on the outside of the shaft (340). The pressure ring (360) has a plurality of evenly distributed annular holes (3601). The inner wall of the support plate (370) is provided with a support rod (3701), and the other end of the support rod (3701) is adapted to pass through the annular hole (3601).

9. A shale gas extraction drilling tool with a self-lubricating drill bit according to claim 1, characterized in that, The protective pad (3702) has a slot (3703) at one end facing the fixing block (310). The fixing block (310) is provided with multiple sets of limiting plates (3101). Two adjacent limiting plates (3101) are used to provide limiting constraints for the extension of the support plate (370). Two adjacent slots (3703) facilitate the quick loading and unloading of the inner teeth (380).

10. A shale gas extraction drilling tool with a self-lubricating drill bit according to claim 1, characterized in that, Two second springs (390) are symmetrically distributed between the support plate (370) and the pressure-resistant sub-shell (330). The pressure-resistant sub-shell (330) has multiple holes inside. The T-shaped rod segment inside the inner toothed rack (380) is adapted to penetrate into the holes inside the pressure-resistant sub-shell (330).

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