Self-lubricating PDC-roller mixed drill bit

Abstract

The utility model belongs to the technical field of petroleum and geological drilling tools, and particularly relates to a self-lubricating PDC-roller mixed drill bit. The self-lubricating PDC-roller mixed drill bit comprises a drill bit body used for being connected with a drill column, a PDC assembly arranged on the drill bit body and a roller assembly arranged on the drill bit body, wherein the roller assembly comprises a roller palm arm fixedly connected to the drill bit body; the roller shaft is arranged on the roller palm arm; the rolling wheel is rotationally arranged on the roller shaft, and one end, far away from the roller shaft, of the rolling wheel is rotationally connected with the drill bit body; the oil bag and the oil channel are arranged in the roller palm arm, the oil bag is located at the position deviating from the central axis of the drill bit body, the oil bag is made of flexible materials, and the oil channel enables the oil bag to be communicated between the roller shaft and the rolling wheel from the position, close to the outer side, of the oil bag.

Description

[0001] Cross Reference to Related Applications

[0002] This application claims priority to international patent application PCT / CN2023 / 139329 entitled "A PDC-roller hybrid drill bit" filed on December 18, 2023, the entire contents of which are incorporated herein by reference. TECHNICAL FIELD

[0003] The utility model belongs to petroleum and geological drilling tool technical field, specifically, relate to a self -lubricating PDC - roller hybrid drill bit. BACKGROUND

[0004] In the field of oil and gas drilling and geological drilling, the drill bit is an essential downhole tool in the drilling process. The drill bit breaks the formation rock and drills into the formation, thereby forming a borehole. The design and selection of the drill bit are critical to improving the rock breaking efficiency of complex formations, improving drilling speed, and reducing drilling cost. Therefore, the quality of a borehole and the length of time used for drilling are closely related to the structure and performance of the drill bit.

[0005] PDC (polycrystalline diamond compact) drill bits can achieve good results in soft to medium-hard formations, and therefore have been widely used in oil and gas drilling. However, in some medium to hard formations, especially in heterogeneous formations, PDC drill bits have the problems of low mechanical drilling speed and insufficient life. In directional wells, horizontal wells, extended reach wells, and branch wells, PDC drill bits have the problem of unstable tool face, especially in small hole deviation conditions. Many times, a roller bit is needed to be used first for directional drilling, and the roller bit has low mechanical drilling speed and footage in some heterogeneous hard formations. Moreover, in heterogeneous formations, especially in formations above medium formations, the roller bit is prone to tooth breakage, has slow mechanical drilling speed, and has less footage.

[0006] There are PDC-roller hybrid drill bits in the prior art, which have the advantages of both PDC drill bits and roller bits, and the use of such drill bits has achieved certain results in speed improvement and directional efficiency. However, after long-term use of such drill bits, the roller and roller shaft are often severely worn and fail, resulting in problems such as short service life of the hybrid drill bit and low life. SUMMARY

[0007] In view of the above technical problems, the present utility model aims to provide a self-lubricating PDC-roller hybrid drill bit that can solve at least one of the above problems.

[0008] The utility model provides a kind of self-lubricating PDC-roller hybrid drill bit, comprising: the drill bit body for connecting drill string, PDC component being arranged on the drill bit body and roller component being arranged on the drill bit body, the roller component includes:

[0009] Roller palm arm fixedly connected on the drill bit body;

[0010] Roller shaft being arranged on the roller palm arm;

[0011] Rolling wheel being rotatably arranged on the roller shaft, and the end of rolling wheel away from the roller shaft is rotatably connected with the drill bit body;And

[0012] Oil bag and oil channel being arranged in the roller palm arm, the oil bag is located at the position deviating from the central axis of the drill bit body, the oil bag is made of flexible material, and the oil channel is communicated from the position close to the outside of the oil bag to between the roller shaft and the rolling wheel.

[0013] In one specific embodiment, first blind hole is arranged in the rolling wheel along axis, and the roller shaft is coaxially arranged in the first blind hole, so that the rolling wheel is rotatably arranged on the roller shaft.

[0014] In one specific embodiment, second support shaft is coaxially fixedly arranged at the end of the rolling wheel away from the first blind hole, third blind hole for accommodating the second support shaft is arranged on the drill bit body, the second support shaft is coaxially rotatably arranged in the third blind hole, and the axis of the first blind hole and third blind hole is aligned with each other.

[0015] In one specific embodiment, sealing assembly is arranged between the roller shaft and second support shaft and the rolling wheel, the sealing assembly includes first seal and second seal axially connected together, and the connecting surface of the first seal and the second seal is configured as polished surface.

[0016] In one specific embodiment, the friction resistance of the first seal is lower than that of the second seal, and the hardness of the first seal is greater than that of the second seal.

[0017] In one specific embodiment, oil cup is arranged in the roller palm arm, the oil bag is located in the oil cup, and balance hole is arranged in the roller palm arm to communicate the oil cup with outside.

[0018] In one specific embodiment, the balance hole communicates the space between the rolling wheel and roller palm arm with the oil cup.

[0019] In one specific embodiment, an oil cup is provided with a first plug at one end away from the balance hole, and an oil injection hole is formed in the first plug and communicates with the inside of the oil bag.

[0020] In one specific embodiment, the PDC assembly includes cutting teeth fixedly connected to the drill bit body for cutting, and a plurality of rolling teeth are arranged on the outer wall of the rolling wheel, the rolling teeth are arranged to extend beyond the cutting teeth, so that the rolling wheel can crush the rock by rotating before the PDC assembly cuts the rock of the stratum, and the tooth height of the rolling teeth is arranged to be 0.01-5mm greater than the tooth height of the cutting teeth.

[0021] In one specific embodiment, a central flow channel and a nozzle are arranged in the inside of the drill bit body.

[0022] Compared with the prior art, the advantages of the present application are as follows.

[0023] The self-lubricating PDC-rolling wheel hybrid drill bit combines the rolling wheel assembly and the PDC assembly together, has high mechanical drilling speed and good tool face stability, can significantly improve the mechanical drilling speed and footage, and achieves the purposes of reducing the labor intensity of workers, reducing the drilling cost, and accelerating the exploration and development speed of oil and gas fields and mining sites.

[0024] In the working process of the self-lubricating PDC-rolling wheel hybrid drill bit, the rolling teeth in the rolling wheel assembly first crush the rock of the stratum, form cracks and other defects in the uncrushed stratum, reduce the crushing strength of the rock of the stratum, and then are cut by the cutting teeth in the PDC assembly. On the one hand, the rolling teeth only crush the bottom hole rock in a pretreatment manner, which greatly reduces the working load and stress. On the other hand, the cutting teeth in the PDC assembly cut the weakened rock of the stratum, which greatly improves the drillability of the rock of the stratum and greatly improves the stress on the cutting teeth. As a result, the service life of the rolling wheel assembly and the PDC assembly is greatly improved. At the same time, the rolling teeth on the rolling wheel are arranged in a spaced manner, and the self-lubricating PDC-rolling wheel hybrid drill bit can generate periodic axial vibration along the drill bit body through the rolling of the rolling wheel, which is very beneficial to stabilizing the working face and improving the drilling pressure transmission efficiency, thereby promoting the tool face stability of the self-lubricating PDC-rolling wheel hybrid drill bit during drilling, and is very beneficial to improving the drilling operation efficiency of the drill bit and enhancing the drilling effect.

[0025] The utility model discloses a lubricating oil liquid is arranged at the contact part of the roller axle and the rolling wheel, and the oil bag is used to supplement the lubricating oil liquid. Since the oil bag deviates from the central axis of the drill bit, in the process of drilling, the oil bag and the oil liquid in it are affected by centrifugal force, the oil bag is self-adaptively deformed, so that the oil liquid is squeezed into the oil channel, and then the contact surface of the roller axle and the rolling wheel is lubricated, the wear of the roller axle and the rolling wheel is avoided, and the service life of the roller assembly is prolonged. Meanwhile, a composite sealing ring, i. e. a first sealing member and a second sealing member, is arranged in the sealing assembly at the two ends of the roller axle, the sealing effect between the roller axle and the rolling wheel is strengthened, and the service life is prolonged. BRIEF DESCRIPTION OF DRAWINGS

[0026] The utility model will be described below with reference to the drawings.

[0027] Figure 1 An embodiment structure of the self-lubricating PDC-rolling wheel hybrid drill bit according to the utility model is schematically shown;

[0028] Figure 2 The structure of another embodiment of the self-lubricating PDC-rolling wheel hybrid drill bit according to the utility model is schematically shown;

[0029] Figure 3 The end structure of the self-lubricating PDC-rolling wheel hybrid drill bit according to the utility model is schematically shown.

[0030] In the drawing: 1, drill bit body; 11, rolling wheel area; 12, PDC area;

[0031] 2, connecting joint; 21, shackle groove;

[0032] 3, rolling wheel assembly; 31, rolling wheel arm; 311, oil bag; 312, oil channel; 314, balance hole; 315, oil cup; 316, first plug; 317, oil injection hole; 32, roller axle; 323, second plug; 33, rolling wheel; 331, rolling wheel diameter correction tooth; 332, first gauge protection tooth; 333, first blind hole; 335, second support shaft; 34, rolling wheel tooth; 35, shaft seat;

[0033] 4, PDC assembly; 41, blade; 42, cutting tooth; 43, gauge protection block; 431, second gauge protection tooth; 44, active gauge protection tooth; 46, superhard coating; 47, third blind hole;

[0034] 6, sealing assembly;

[0035] 7, second auxiliary cutting tooth;

[0036] 8, central flow channel;

[0037] 9, nozzle;

[0038] 10. first auxiliary cutting tooth;

[0039] 100. Self-lubricating PDC-roller hybrid drill bit.

[0040] In the present application, all the drawings are schematic drawings, which are only used for explaining the principles of the present application and are not necessarily drawn in actual proportions. DETAILED DESCRIPTION

[0041] The present application will be described below with reference to the drawings.

[0042] In the present application, it is to be noted that the directional terms or limiting terms "upper", "lower" and the like used in the present application are all with reference to the drawings. Figure 1 They are not used to limit the absolute positions of the involved parts, but can be changed according to the specific circumstances.

[0043] Figure 1 The structure of the self-lubricating PDC-roller hybrid drill bit 100 according to the present application is schematically shown. As shown, the self-lubricating PDC-roller hybrid drill bit 100 comprises a drill bit body 1, a roller assembly 3 and a PDC assembly 4. The drill bit body 1 is generally in the shape of a cylinder, and a connection joint 2 is configured at the upper end of the drill bit body 1 for connecting with a drill string (not shown) that drives the drill bit body 1 to rotate. The drill bit body 1 can be connected to the drill string through the connection joint 2, so that the drill bit body 1 can be lowered into an oil well together with the drill string and rotate together with the drill string. Figure 1 The drill bit body 1 is divided into a roller zone 11 and a PDC zone 12 by a plane passing through the axis of the drill bit body 1. The roller assembly 3 is installed at the lower part of the roller zone 11 of the drill bit body 1 and faces the working end face. The PDC assembly 4 is arranged at the lower part of the PDC zone 12 of the drill bit body 1 and faces the working end face.

[0044] According to the present application, the roller assembly 3 comprises a roller arm 31 fixedly connected with the drill bit body 1, a roller shaft 32 fixedly connected with the roller arm 31, a rolling wheel 33 installed on the roller shaft 32, and a plurality of roller teeth 34 embedded on the rolling wheel 33, which are arranged along the circumferential surface of the rolling wheel 33, especially uniformly. With the rotation of the drill bit body 1, the rolling wheel 33 can crush the formation rock through the roller teeth 34, thereby reducing the hardness of the formation rock. In the present embodiment, the roller shaft 32 is fixedly arranged at the lower end of the roller arm 31 and is arranged to extend generally along the radial direction of the drill bit body 1 and to be inclined toward the PDC assembly 4. The rolling wheel 33 is generally in the shape of a sphere and is coaxially rotatably arranged on the roller shaft 32.

[0045]

[0046] ​In one specific embodiment, a first blind hole 333 for the roller shaft 32 to pass through is arranged at one end of the rolling wheel 33 along the central axis, and the rolling wheel 33 is rotatably arranged on the roller shaft 32 through the first blind hole 333.

[0047] According to the present application, the oil tank 311 and the oil channel 312 are arranged in the roller arm 31. The oil tank 311 is filled with lubricating oil, and the oil channel 312 is connected to the oil tank 311. The oil in the oil tank 311 can flow along the oil channel 312 to the contact surface between the roller shaft 32 and the rolling wheel 33. Through this arrangement, on the one hand, the friction between the rolling wheel 33 and the roller shaft 32 is reduced, and the service life of the roller assembly 3 is prolonged. On the other hand, the gap between the rolling wheel 33 and the roller shaft 32 is filled with oil, preventing gravel from entering during work and damaging the rolling wheel 33 or the roller shaft 32.

[0048] Further, the oil cup 315 is arranged in the roller arm 31, and the oil cup 315 is a cylindrical barrel arranged in the roller arm 31. The oil tank 311 is located in the oil cup 315, and the balance hole 314 is arranged in the roller arm 31 to connect the oil cup 315 to the outside. Through this arrangement, when the oil in the oil cup 315 is consumed during work, the oil tank 311 will shrink under the action of atmospheric pressure, thereby ensuring that the oil in the oil cup 315 can flow smoothly between the roller shaft 32 and the rolling wheel 33.

[0049] In a preferred embodiment, the oil cup 315 is located away from the central axis of the drill bit body 1, so that the oil tank 311 is also away from the central axis of the drill bit body 1. In this arrangement, during drilling of the drill bit, the oil tank 311 and the oil inside it are subjected to centrifugal force, and the oil tank 311 undergoes self-adaptive deformation, so that the oil is squeezed into the oil channel 312, thereby lubricating the contact surface of the roller shaft 32 and the rolling wheel 33, avoiding wear of the roller shaft 32 and the rolling wheel 33, and prolonging the service life of the roller assembly 3.

[0050] Further, the oil channel 312 connects the oil tank 311 to between the roller shaft 32 and the rolling wheel 33 from a position close to the outside of the oil tank 311. That is, the connection point of the oil channel 312 and the oil tank 311 is located at a position close to the radial outside of the drill bit body 1. In this arrangement, when the oil tank 311 deforms under the action of centrifugal force, the oil inside the oil tank 311 can also automatically enter the oil channel 312 under the action of centrifugal force, thereby enhancing the lubrication of the contact surface of the roller shaft 32 and the rolling wheel 33, avoiding wear of the roller shaft 32 and the rolling wheel 33, and prolonging the service life of the roller assembly 3.

[0051] In a preferred embodiment, the balance hole 314 connects the space between the rolling wheel 33 and the roller arm 31 to the oil cup 315. As shown in the figure, the balance hole 314 is arranged in the roller arm 31, and the balance hole 314 is connected to the oil cup 315 and the outside. Figure 1As shown, there is a space between the roller arm 31 and the rolling wheel 33, and the balance hole 314 passes through the space to connect the oil bag 311 with the outside, which on one hand ensures that the oil bag 311 can work normally under the atmospheric pressure, and on the other hand prevents the balance hole 314 from being blocked by the rock cuttings during the drilling process.

[0052] In one specific embodiment, the oil cup 315 is provided with a first plug 316 at the end away from the balance hole 314, and the first plug 316 is provided with an oil injection hole 317 which is in communication with the inside of the oil bag 311, and the oil injection hole 317 is provided with an oil injection plug 318. Through this arrangement, when the oil bag 311 is short of oil, the oil injection plug 318 can be removed from the oil injection hole 317, and the oil cup 315 can be filled with oil through the oil injection hole 317.

[0053] As shown, Figure 1 In this embodiment, the rolling wheel 33 is provided with a first blind hole 333 and a second support shaft 335 at the two axial ends respectively. The central axes of the first blind hole 333 and the second support shaft 335 coincide. The roller shaft 32 is coaxially rotatably arranged in the inside of the first blind hole 333, so that the rolling wheel 33 is rotatably connected with the roller shaft 32. The drill bit body 1 is provided with a third blind hole 47, the central axis of the third blind hole 47 coincides with the central axis of the roller shaft 32, and the second support shaft 335 is coaxially rotatably arranged in the inside of the third blind hole 47, so that the rolling wheel 33 is rotatably connected with the PDC assembly 4. In this arrangement, the two axial ends of the rolling wheel 33 are supported by the roller arm 31 and the drill bit body 1 respectively, so as to enhance the load bearing capacity of the roller shaft 32 and the rolling wheel 33. The left and right axial ends of the rolling wheel 33 are supported by the roller shaft 32 and the drill bit body 1 respectively, so as to disperse the formation pressure received by the rolling wheel 33 during the working process to the PDC assembly 4 and the roller shaft 32, reduce the strength of the force received by the roller shaft 32, and prolong the service life of the roller shaft 32. Further, the force received by the roller shaft 32 is reduced, which can avoid the damage of the internal sealing assembly 6 caused by the excessive inclination of the roller shaft 32, and thus prolong the service life of the rolling wheel 33 itself.

[0054] In one preferred embodiment, as shown, Figure 2 The third blind hole 47 and the second support shaft 335 are both provided with a superhard coating 46. Through this arrangement, the contact surface of the third blind hole 47 and the second support shaft 335 can be more wear-resistant, and the formation cuttings can also be prevented from entering between the third blind hole 47 and the second support shaft 335. It is easy to understand that the specific composition of the superhard coating 46 is well known to those skilled in the art, such as diamond, and will not be described here.

[0055] As shown, Figure 1As shown, in one preferred embodiment, a sealing assembly 6 is arranged between the second support shaft 335 of the rolling wheel 33 and the third blind hole 47 of the PCD assembly 4. The specific structure of the sealing assembly 6 can refer to the structure in the first embodiment of the utility model, which will not be described here. By arranging the sealing assembly 6, the lubricating oil can be stored between the third blind hole 47 and the second support shaft 335, thereby prolonging the service life of the third blind hole 47 and the second support shaft 335. In addition, the sealing assembly 6 can also prevent the formation of rock debris from entering between the third blind hole 47 and the second support shaft 335.

[0056] According to the utility model, a sealing assembly 6 is arranged between the rolling wheel 33 and the roller shaft 32. The sealing assembly 6 comprises a first sealing member and a second sealing member arranged on the roller shaft 32 and connected together.

[0057] In one embodiment of the sealing assembly 6, the connecting surfaces of the first sealing member and the second sealing member are both configured as polished surfaces, thereby closing the fine gap between the roller shaft 32 and the rolling wheel 33 and enhancing the sealing effect.

[0058] In one preferred embodiment, the hardness of the first sealing member is greater than that of the second sealing member, and the frictional resistance of the first sealing member is lower than that of the second sealing member.

[0059] Preferably, the first sealing member is made of a material with high hardness, wear resistance and low frictional resistance, such as PTFE bronze, PTFE carbon fiber, PTFE glass fiber, PTFE red copper or PTFE brass. The second sealing member is made of a material with low hardness and good elasticity, such as nitrile rubber, saturated nitrile rubber or fluorine rubber. Both the first sealing member and the second sealing member can play the role of supporting and sealing between the roller shaft 32 and the rolling wheel 33, the first sealing member mainly plays the role of supporting, and the second sealing member mainly plays the role of sealing, and the two mutually assist each other. In this embodiment, the first sealing member and the second sealing member can be configured as an integrated structure or as a split structure. That is, the first sealing member and the second sealing member can be combined as one part, and the first sealing member and the second sealing member are manufactured as one part in the process of manufacturing. Through this integrated structure, the installation process can be more convenient. Alternatively, the first sealing member and the second sealing member can be manufactured as two parts and used in the installation process. This split structure makes the part processing and manufacturing more convenient.

[0060] According to the utility model, an axle seat 35 is arranged at the lower end of the roller area 11 of the drill bit body 1, and the third blind hole 47 for installing the second support shaft 335 is located in the axle seat 35.

[0061] The PDC assembly 4 comprises a blade 41 and cutting teeth 42 embedded on the blade 41, and the cutting teeth 42 are arranged in a plurality of groups and evenly arranged on the blade 41. The roller teeth 34 are arranged to extend beyond the cutting teeth 42, so that the rolling wheel 33 can crush the rock by rotating before the PDC assembly 4 cuts the rock of the formation. It can also be understood that the lower end edge of the cutting teeth 42 is located between the lower end edge of the roller teeth 34 and the lower end edge of the rolling wheel 33. It should be noted that the working end face here refers to the surface of the crushed and cut rock, and the lower end edge here refers to the lowermost end in the direction of the axis of the self-lubricating PDC-rolling wheel hybrid drill bit 100.

[0062] In operation, the self-lubricating PDC-rolling wheel hybrid drill bit 100 rotates along its axis, and the working end face faces the formation to be drilled. The rolling wheel assembly 3 can first pre-process and crush the rock of the formation, and form cracks and other defects in the unbroken formation, so as to reduce the crushing strength of the rock of the formation, and then the PDC assembly 4 cuts the rock of the formation which has been pre-crushed, full of cracks and weakened. That is, when the self-lubricating PDC-rolling wheel hybrid drill bit 100 rotates along its axis, the rolling wheel 33 rotates around the roller shaft 32 under the friction of the formation. In the process of rotating, the roller teeth 34 are in intermittent contact with the formation, so that the self-lubricating PDC-rolling wheel hybrid drill bit 100 generates periodic vibrations in the axial direction. Since the lower end edge of the roller teeth 34 is lower than the lower end edge of the cutting teeth 42, when the roller teeth 34 are in contact with the formation, the cutting teeth 42 are not in contact with the formation. At this time, the roller teeth 34 pre-process and crush the formation. When the rolling wheel 33 rotates to the point where the roller teeth 34 are not in contact with the formation, the cutting teeth 42 are in contact with the formation. At this time, the cutting teeth 42 cut the formation to periodically perform drilling work.

[0063] Thus, on the one hand, the rolling wheel assembly 3 locally and partially crushes the bottom hole rock, and the working load and stress are greatly reduced, and the oil cavity 311 and the oil channel 312 further reduce the friction between the roller shaft 32 and the rolling wheel 33, prolonging the service life. On the other hand, the cutting teeth 42 of the PDC assembly 4 cut the weakened rock of the formation, and the drillability of the rock of the formation is greatly improved, and the stress on the cutting teeth 42 is greatly improved, which greatly improves the service life of the rolling wheel assembly 3 and the PDC assembly 4. At the same time, the rolling of the rolling wheel 33 generates periodic axial vibrations and transmits them to the drill string, effectively improving the stability of the working face of the directional well and the efficiency of the drilling pressure transmission, greatly improving the footage, the rate of penetration and the directional characteristics in the heterogeneous formation, which is very beneficial to the speed-up and cost reduction of oil and gas field and mine exploration and development.

[0064] In a preferred embodiment, the tooth height of the roller tooth 34 is set to be 0.01-5mm higher than the tooth height of the cutting tooth 42. Alternatively, the lower end edge wall of the roller tooth 34 is set to be 0.01-5mm lower than the lower end edge of the cutting tooth 42. Within this range, the working efficiency is high.

[0065] In an embodiment, the connecting joint 2 at the upper end of the drill bit body 1 can be configured as a tapered connecting buckle, and is fixedly connected with the drill string by a threaded connection. Meanwhile, a disconnection groove 21 is further arranged on the outer wall of the tapered connecting buckle in a circumferential direction, for realizing quick disconnection between the self-lubricating PDC-roller hybrid drill bit 100 and the upper drill string. Through this structure, the drill bit body 1 is not only convenient to install and connect, but also convenient to disassemble, and the disassembly efficiency can be significantly improved.

[0066] As shown in Figure 1 , the PDC assembly 4 and the roller assembly 3 are arranged at the lower end of the drill bit body 1. Meanwhile, the PDC assembly 4 and the roller assembly 3 are arranged as one or more. The one or more PDC assemblies 4 and the roller assemblies 3 are arranged to be alternately arranged along the circumferential direction of the drill bit body 1. Thus, when the drill bit body 1 rotates synchronously with the drill string, the PDC assembly 4 and the roller assembly 3 can periodically and alternately perform cutting operations on the same position of the stratum.

[0067] In a preferred embodiment, the PDC assembly 4 and the roller assembly 3 are arranged to be radially opposite.

[0068] In a preferred embodiment, a reinforcing layer 38 is further coated on the outer wall of the roller shaft 32, the rolling wheel 33 and the roller arm 31, respectively. The reinforcing layer 38 is preferably made of tungsten carbide material. On the one hand, this tungsten carbide material has good oxidation resistance and corrosion resistance, and can protect the roller shaft 32, the rolling wheel 33 and the roller arm 31, thereby reducing the risk of oxidation and corrosion. On the other hand, this material has good wear resistance, which can reduce the wear resistance of the roller shaft 32 and the rolling wheel 33, thereby further improving the service life of the roller shaft 32 and the rolling wheel 33.

[0069] In a specific embodiment, the shaft seat 35 and the roller arm 31, the sealing surface of the rolling wheel 33 and the roller shaft 32 are subjected to nitriding, carburizing, carbonitriding, boronizing treatment, or are coated with tungsten carbide on the surface of the material, or are directly made of corresponding materials subjected to nitriding, carburizing, carbonitriding, boronizing, such as carburizing steel, or can be made of ceramic material. By such arrangement, the friction is reduced, and the sealing between the shaft seat 35 and the end surface of the rolling wheel 33 and the sealing between the rolling wheel 33 and the roller arm 31 are increased.

[0070] According to the utility model, as Figure 1As shown, the roller arm 31 is fixedly connected with the outer wall of the drill bit body 1. For example, the roller arm 31 can be fixed on the outer wall of the drill bit body 1 by welding.

[0071] In a preferred embodiment, the roller shaft 32 is integrally arranged with the roller arm 31. The included angle between the roller shaft 32 and the roller arm 31 is obtuse, and the roller shaft 32 is arranged to extend inwardly and downwardly. In this way, the rolling wheel 33 is directed towards the working end face.

[0072] In an embodiment, the profile line of the rolling wheel 33 is an arc-shaped line with high middle and low sides. The roller teeth 34 are embedded in the middle of the rolling wheel 33 and arranged circumferentially. The roller teeth 34 are provided in plurality, and the plurality of roller teeth 34 are uniformly distributed in the circumferential direction. This structure of the roller assembly 3 is very beneficial to breaking the stratum rock. The rolling wheel 33 is mounted on the roller shaft 32 and rotatably connected with the roller shaft 32.

[0073] According to an embodiment of the present application, the contact surface between the rolling wheel 33 and the roller shaft 32 forms a sliding bearing, so that the two are rotatably connected. Preferably, an intermediate sliding sleeve or the like can be added between the sliding bearing surfaces. This can greatly improve the service life of the rolling wheel 33, thereby facilitating the improvement of the service life of the self-lubricating PDC-roller hybrid drill bit 100.

[0074] According to the present application, the roller teeth 34 are configured as first special-shaped teeth. The first special-shaped teeth can be conical teeth, wedge-shaped teeth, spherical teeth, spoon-shaped teeth or oval teeth, etc. The roller teeth 34 can be made of hard alloy, ceramic or PDC material. This can significantly improve the adaptability of the roller assembly 3 to the stratum rock.

[0075] According to the present application, as shown in the drawings, Figure 1 The first gauge protection teeth 332 are embeddedly mounted on the outer wall surface of the roller arm 31. Meanwhile, in a preferred embodiment, the roller gauge correction teeth 331 are also provided on the profile line of the rolling wheel 33 at the radially outermost side. In this way, the first gauge protection teeth 332 and the roller gauge correction teeth 331 can effectively protect the hole diameter drilled by the self-lubricating PDC-roller hybrid drill bit 100 from being reduced during drilling, thereby ensuring the drilling performance and directional performance of the self-lubricating PDC-roller hybrid drill bit 100.

[0076] According to the present application, the PDC assembly 4 further comprises a gauge block 43 formed on the radially outer side of the blade 41, and the second gauge protection teeth 431 are embeddedly mounted on the gauge block 43.

[0077] The cutter wing 41 covers the drill body 1, and the gauge block 43 is preferably integrally formed with the cutter wing 41. For example, a portion of the radially outer side of the cutter wing 41 is formed as the gauge block 43.

[0078] like Figure 1 As shown, an active diameter-maintaining tooth 44 can also be provided on the diameter-maintaining block 43. The active diameter-maintaining tooth 44 is located between the second diameter-maintaining tooth 431 and the cutting tooth 42, and the maximum outer diameter of the active diameter-maintaining tooth 44 is greater than or equal to the maximum outer diameter of the second diameter-maintaining tooth 431. Thus, the first diameter-maintaining tooth 332, the roller diameter-maintaining tooth 331, the second diameter-maintaining tooth 431, and the active diameter-maintaining tooth 44 work together to effectively protect the diameter of the hole drilled by the self-lubricating PDC-roller hybrid drill bit 100 from shrinking during the drilling process, further ensuring the drilling performance and directional performance of the self-lubricating PDC-roller hybrid drill bit 100.

[0079] According to this invention, the PDC component 4 is made of PDC (polycrystalline diamond composite) material. Specifically, the cutter wing 41, cutting teeth 42, gauge block 43, second gauge-keeping tooth 431, and active gauge-keeping tooth 44 are all made of PDC (polycrystalline diamond composite) material. This effectively ensures the strength of the PDC component 4, thereby guaranteeing the cutting performance of the self-lubricating PDC-roller hybrid drill bit 100.

[0080] Preferably, the cutting teeth 42 can be configured as planar teeth, conical teeth, ridged teeth, and triangular teeth, etc. This can further improve the cutting performance of the self-lubricating PDC-roller hybrid drill bit 100.

[0081] According to one embodiment of the present invention, such as Figure 3 As shown, the cutter wing 41 may be provided with a first auxiliary cutting tooth 10, which is located after the cutting tooth 42. Preferably, the cutter wing 41 may also be provided with a second auxiliary cutting tooth 7. Similarly, the second auxiliary cutting tooth 7 is located after the cutting tooth 42, and the second auxiliary cutting tooth 7 and the first auxiliary cutting tooth 10 are radially spaced apart from each other. It should be understood that "before" and "after" here refer to the order in which the cutting tooth 42 encounters the formation during the rotation of the drill bit body 1, and "after" refers to the side that lags behind the cutting tooth 42 in contacting the formation rock.

[0082] Both the first auxiliary cutting tooth 10 and the second auxiliary cutting tooth 7 are made of cemented carbide, ceramic or PDC material.

[0083] According to this utility model, such as Figure 1As shown, the center flow channel 8 extending along the axial direction and the nozzle 9 are arranged in the drill bit body 1. The center flow channel 8 is arranged in the drill bit body 1 and is communicated with the drill string, and the center flow channel 8 has the nozzle 9 extending to the blade 41, so that the fluid in the drill string can be sprayed to the blade 41. The nozzle 9 is at an angle with the center flow channel 8, so that the nozzle 9 is aligned with the working end face. The drilling fluid from the drill string can be sequentially sprayed to the stratum rock surface aligned with the self-lubricating PDC-roller hybrid drill bit 100 through the center flow channel 8 and the nozzle 9. On one hand, the drilling fluid sprayed by the nozzle 9 can impact the stratum rock and soften the stratum rock. On the other hand, the drilling fluid sprayed by the nozzle 9 can clean the roller assembly 3 and the PDC assembly 4, effectively avoid the drill cuttings from being adhered to the roller 33 or the blade 41, and is very beneficial to improve the rate of penetration of the self-lubricating PDC-roller hybrid drill bit 100 and ensure the drilling performance of the self-lubricating PDC-roller hybrid drill bit 100.

[0084] A plurality of nozzles 9 can be arranged in the drill bit body 1, so as to ensure the flow effect and efficiency of the drilling fluid and ensure the cleaning and cooling of the roller assembly 3 and the PDC assembly 4.

[0085] In the description of the present application, the description of the terms “one embodiment”, “some embodiments”, “an example”, “a specific example” or “some examples” means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the description of the present application, the illustrative description of the above terms does not necessarily mean the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0086] In the description of the present application, it should be understood that the terms “first”, “second” are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features limited by “first”, “second” can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of “a plurality of” is two or more, unless otherwise specifically limited.

[0087] In the present application, unless otherwise specifically defined and limited, the terms “mounting”, “connection”, “connection”, “fixing” and the like should be understood in a broad sense, for example, can be fixedly connected, or can be detachably connected, or integrally connected; can be mechanically connected, or can be electrically connected; can be directly connected, or can be indirectly connected through an intermediate medium, or can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0088] Finally, it should be noted that the above only for the preferred embodiments of the present application, and does not constitute any limitation on the present application. Although the present application is described in detail with reference to the foregoing embodiments, but for those skilled in the art, the technical solutions recorded in the foregoing examples can be modified, or part of the technical features of the equivalent replacement. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application, shall be included within the scope of the present application.

Claims

1. A self-lubricating PDC-roller hybrid bit comprising: A drill bit body (1) for connecting a drill string, a PDC assembly (4) arranged on the drill bit body, and a roller assembly (3) arranged on the drill bit body, characterized in that the roller assembly comprises: a roller arm (31) fixedly connected to the drill bit body; a roller shaft (32) arranged on the roller arm; a roller wheel (33) rotatably arranged on the roller shaft (32), an end of the roller wheel (33) away from the roller shaft (32) being rotatably connected to the drill bit body (1); and an oil pocket (311) and an oil channel (312) arranged in the roller arm (31), the oil pocket (311) being located at a position deviating from a central axis of the drill bit body (1), the oil pocket (311) being made of flexible material, and the oil channel (312) being arranged from a position close to an outer side of the oil pocket (311) to communicate the oil pocket (311) to a space between the roller shaft (32) and the roller wheel (33).

2. The self-lubricating PDC-roller hybrid bit of claim 1, wherein, A first blind hole (333) is arranged in the roller wheel (33) along an axis, and the roller shaft (32) is coaxially arranged in the first blind hole (333), so that the roller wheel (33) is rotatably arranged on the roller shaft (32).

3. The self-lubricating PDC-roller hybrid bit of claim 2, wherein, A second support shaft (335) is coaxially and fixedly arranged at an end of the roller wheel (33) away from the first blind hole (333), and a third blind hole (47) for accommodating the second support shaft (335) is arranged on the drill bit body (1), the second support shaft (335) is coaxially and rotatably arranged in the third blind hole (47), and the axes of the first blind hole (333) and the third blind hole (47) are aligned with each other.

4. The self-lubricating PDC-roller hybrid bit of claim 2, wherein, A sealing assembly (6) is arranged between the roller shaft (32) and the second support shaft (335) and the roller wheel (33), the sealing assembly (6) comprises a first sealing member and a second sealing member axially connected together, and the connecting surfaces of the first sealing member and the second sealing member are configured as polished surfaces.

5. The self-lubricating PDC-roller hybrid bit of claim 4, wherein, The frictional resistance of the first sealing member is lower than that of the second sealing member, and the hardness of the first sealing member is greater than that of the second sealing member.

6. The self-lubricating PDC-roller hybrid drill bit of any one of claims 1-5, wherein, An oil cup (315) is arranged in the roller arm (31), and the oil pocket (311) is located in the oil cup (315), and a balance hole (314) for communicating the oil cup (315) with the outside is arranged in the roller arm (31).

7. The self-lubricating PDC-roller hybrid bit of claim 6, wherein, The balance hole (314) communicates a space between the roller wheel (33) and the roller arm (31) with the oil cup (315).

8. The self-lubricating PDC-roller hybrid bit of claim 7, wherein, An end of the oil cup (315) away from the balance hole (314) is provided with a first plug (316), and an oil injection hole (317) is formed in the first plug (316) and communicates with the inside of the oil pocket (311).

9. The self-lubricating PDC-roller hybrid bit according to any one of claims 1 to 5, wherein, The PDC assembly comprises cutting teeth (42) fixedly connected with the drill bit body (1) for cutting, a plurality of rolling teeth (34) are arranged on the outer wall of the rolling wheel, the rolling teeth are arranged to extend beyond the cutting teeth, so that the rolling wheel can crush rocks by rotating before the PDC assembly cuts the stratum rocks, the tooth height of the rolling teeth is arranged to be 0.01-5mm greater than the tooth height of the cutting teeth.

10. The self-lubricating PDC-roller hybrid bit according to any one of claims 1 to 5, wherein, A center flow channel (8) and a nozzle (9) are arranged in the interior of the drill bit body.

Images