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 PDC-roller mixed drill bit. The PDC-roller hybrid drill bit comprises a drill bit body used for being connected with a drill column; the PDC assembly is arranged on the drill bit body; the drill bit comprises a drill bit body and a roller assembly arranged on the drill bit body, the roller assembly comprises a roller palm arm fixedly connected to the drill bit body, a roller shaft is arranged on the roller palm arm, a rolling wheel is rotationally arranged on the roller shaft, and a sealing assembly is arranged between the roller shaft and the rolling wheel. The sealing assembly comprises a first sealing piece and a second sealing piece, the hardness of the first sealing piece is larger than that of the second sealing piece, sealing is formed between the first sealing piece and the second sealing piece, and dynamic sealing is formed between the first sealing piece and the roller shaft. Static sealing is formed between the second sealing piece and the rolling wheel.

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, concretely relates to a PDC-roller hybrid drill bit. BACKGROUND

[0004] PDC drill bit can achieve good use effect in soft to medium hard formation, and is widely used in oil and geological drilling. However, in some medium to hard formation, especially in heterogeneous formation, the PDC drill bit has the problems of low mechanical drilling speed and insufficient service life; in directional wells, horizontal wells, large displacement wells and branch wells, the tool face is unstable, especially in the case of small well deviation, the PDC drill bit needs to be used first for directional drilling, which is a bottleneck problem in these applications, and needs to be solved urgently. In heterogeneous formation, especially in medium and above formation, the roller bit is prone to tooth breakage, has slow mechanical drilling speed and small footage, which is a bottleneck problem of the roller bit and needs to be solved urgently.

[0005] The PDC-roller hybrid drill bit has the advantages of PDC drill bit and roller bit, and has achieved certain results in speed increase and directional efficiency improvement. However, this kind of drill bit still faces the problems of short service life, low service life of roller part and premature failure. Compared with the roller, the roller has one more bearing seat, and the service life of the roller will be much higher than that of the roller. The service life of the PDC-roller hybrid drill bit will be much higher than that of the existing PDC-roller hybrid drill bit, which will be more beneficial to speed increase and efficiency improvement. However, the sealing ring at the sealing position of the current roller and roller shaft has the problem of low service life. In order to improve the service life of the sealing ring between the roller and the roller shaft, the sealing ring is usually made of metal material. However, metal sealing requires a large sealing force. When the two ends of the roller shaft are provided with metal seals, the structural characteristics of the roller and the roller shaft of the PDC-roller hybrid drill bit determine that only one of them can provide a large sealing force, which leads to sealing failure. SUMMARY

[0006] In view of the above technical problems, the utility model aims at providing a PDC-roller hybrid drill bit which can solve at least one of the above problems.

[0007] According to the utility model, a PDC-roller hybrid drill bit is provided, which comprises:

[0008] A drill bit body for connecting a drill string;

[0009] A PDC assembly disposed on the drill bit body; and

[0010] A roller assembly disposed on the drill bit body, the roller assembly comprising a roller arm fixedly connected to the drill bit body, a roller shaft disposed on the roller arm, a roller rotatably disposed on the roller shaft, and a sealing assembly disposed between the roller shaft and the roller.

[0011] In one specific embodiment, the sealing assembly comprises a first sealing member and a second sealing member, the first sealing member has a higher hardness than the second sealing member, a seal is formed between the first sealing member and the second sealing member, a dynamic seal is formed between the first sealing member and the roller shaft, and a static seal is formed between the second sealing member and the roller.

[0012] In one specific embodiment, a static seal is formed between the radially outer side of the first sealing member and the radially outer side of the second sealing member.

[0013] In one specific embodiment, the first sealing member and the second sealing member are in an integral structure.

[0014] In one specific embodiment, the first sealing member has a higher wear resistance than the second sealing member.

[0015] In one specific embodiment, the first sealing member has a lower friction than the second sealing member.

[0016] In one specific embodiment, an oil pocket and an oil channel are disposed in the roller arm, the oil channel is configured to enable oil in the oil pocket to flow to the contact surface of the roller shaft and the roller.

[0017] In one specific embodiment, an oil cup is disposed in the roller arm, the oil pocket is located in the oil cup, and a balance hole is disposed in the roller arm to communicate the oil cup with the outside.

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

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

[0020] In one specific embodiment, the axial ends of the roller shaft both extend beyond the rolling wheel, one end of the roller shaft is fixedly connected with the rolling wheel arm, an axle seat is arranged on the PDC assembly, and the other end of the roller shaft is rotatably connected with the axle seat.

[0021] The advantages of the present application are as follows.

[0022] In the working process of the PDC-rolling wheel hybrid drill bit, the rolling wheel assembly first breaks the stratum rock, forms cracks and other defects in the stratum, reduces the breaking strength of the stratum rock, and then the PDC assembly cutting teeth cut the stratum rock which has been pre-broken, covered with cracks and weakened.

[0023] Under the action of the balance hole and the oil bag, the oil bag in the oil cup and the lubricating oil or lubricating grease in the oil channel are continuously supplied to the roller shaft, the rolling wheel, the axle seat and the seal, so that the roller shaft, the rolling wheel, the axle seat and the seal work under the condition of sufficient lubrication, and the service life of the roller and the PDC-rolling wheel hybrid drill bit is greatly improved.

[0024] The sealing assembly comprises a first sealing member and a second sealing member with different physical properties, so that the two parts have different functions, and the service life of the sealing ring is greatly improved. BRIEF DESCRIPTION OF DRAWINGS

[0025] The present application will be described below with reference to the drawings.

[0026] Figure 1 The structure of the PDC-rolling wheel hybrid drill bit according to the present application is schematically shown;

[0027] Figure 2 For Figure 1 An enlarged structure diagram of the middle sealing assembly is shown schematically;

[0028] Figure 3 The top view structure diagram of the PDC-rolling wheel hybrid drill bit according to the present application is schematically shown;

[0029] Figure 4 The structure of another embodiment of the PDC-rolling wheel hybrid drill bit according to the present application is schematically shown;

[0030] Figure 5 The superhard coating in Figure 4 is replaced by the structure of the sealing assembly.

[0031] In the drawings: 1, drill bit body; 11, rolling wheel area; 12, PDC area;

[0032] 2, connecting joint; 21, shackle groove;

[0033] 3. Roller assembly; 31. Roller arm; 311. Oil bladder; 312. Oil passage; 314. Balance hole; 315. Oil cup; 316. First plug; 317. Oil filling hole; 32. Roller shaft; 323. Second plug; 33. Roller; 331. Roller caliper teeth; 332. First caliper protection teeth; 333. First blind hole; 334. Second blind hole; 34. Roller teeth; 35. Shaft seat; 30. Elastic support ring;

[0034] 4. PDC assembly; 41. Blade; 42. Cutting tooth; 43. Gauge protection block; 431. Second gauge protection tooth; 44. Active gauge protection tooth; 45. First support shaft; 46. Ultra-hard coating;

[0035] 6. Sealing assembly; 6. First seal; 62. Second seal;

[0036] 7. Second auxiliary cutting tooth;

[0037] 8. Central flow channel;

[0038] 9. Nozzle;

[0039] 10. First auxiliary cutting tooth;

[0040] 100. PDC-Roller Hybrid Drill Bit.

[0041] In this application, all the accompanying drawings are schematic drawings, used only to illustrate the principle of the present invention, and are not necessarily drawn to scale. Detailed Implementation

[0042] The present invention will now be described with reference to the accompanying drawings.

[0043] In this application, it should be noted that the directional terms or qualifiers such as "up" and "down" used in this application are all in reference to the appendix. Figure 1 In other words, they are not used to define the absolute position of the components involved, but can vary depending on the specific circumstances.

[0044] Example 1:

[0045] Figure 1 The structure of the PDC-roller hybrid drill bit 100 according to this utility model is schematically shown. For example... Figure 1 As shown, the PDC-roller hybrid drill bit 100 includes a drill bit body 1, a roller assembly 3, and a PDC assembly 4. The drill bit body 1 is generally cylindrical, and its lower end is equipped with a connecting joint 2 for connecting to a drill string (not shown) that drives the drill bit body 1 to rotate. The connecting joint 2 allows the drill bit body 1 to be attached to the drill string, enabling it to be lowered into the well along with the drill string and to rotate circumferentially with it.

[0046] The drill body 1 is divided into two parts by a plane passing through its axis: a roller area 11 and a PDC area 12. The roller assembly 3 is mounted on the upper part of the roller area 11 of the drill body 1, facing the working end face. Figure 1 The upper end face of the drill bit body 1). The PDC assembly 4 is located on the upper part of the PDC area 12 of the drill bit body 1, and the PDC assembly 4 faces the working end face.

[0047] According to this utility model, the roller assembly 3 includes a roller arm 31 fixedly connected to the drill bit body 1, a roller shaft 32 fixedly connected to the roller arm 31, a roller 33 mounted under the roller shaft 32, and roller teeth 34 embedded under the roller 33. In this embodiment, the roller shaft 32 is fixedly disposed at the upper end of the roller arm 31, and the roller shaft 32 is configured to extend obliquely approximately along the radial direction of the drill bit body 1 and the direction of the PDC assembly 4. The roller 33 is generally spherical. A hole is provided inside the roller 33 to allow the roller shaft 32 to be inserted, so that the roller 33 can be fitted onto the roller shaft 32.

[0048] According to this utility model, a sealing assembly 6 is provided between the rolling wheel 33 and the rolling wheel shaft 32. For example... Figure 2 As shown, the sealing assembly 6 includes a first seal 61 and a second seal 62 disposed on the roller shaft 32 and connected together.

[0049] According to this utility model, a static seal is formed between the radial outer side of the first sealing member 61 and the radial outer side of the second sealing member 62.

[0050] According to this utility model, the first sealing element 61 and the second sealing element 62 can be an integral structure, or they can be configured as separate structures. That is, the first sealing element 61 and the second sealing element 62 can be combined into one component, manufactured as a single part during the processing and manufacturing process. This integral structure makes the installation process more convenient. Alternatively, the first sealing element 61 and the second sealing element 62 can be manufactured as two separate parts, stacked together during installation. This separate structure makes the manufacturing of the parts more convenient.

[0051] According to this utility model, the wear resistance of the first sealing element 61 is higher than that of the second sealing element 62.

[0052] According to this utility model, the frictional resistance of the first sealing member 61 is lower than that of the second sealing member 62.

[0053] Specifically, the first sealing member 61 is made of high wear-resistant material. According to the present application, the high wear-resistant material can be bronze, carbon fiber, copper, brass, and rubber with high hardness, wear resistance and low friction. These materials have high hardness and can effectively withstand the friction of formation sand, thereby reducing the wear of the second sealing member 61. The second sealing member 62 is made of NBR (nitrile rubber), HNBR (hydrogenated nitrile rubber), FKM (fluorine rubber) and other materials. The first sealing member 61 and the second sealing member 62 form a composite structure and together constitute a sealing wear compensation structure. When assembled, the second sealing member 62 is in a compressed state, providing sufficient pressure for the first sealing member 61 to ensure the sealing of the first sealing member 61 and to compensate for the wear of the first sealing member 61.

[0054] In the present embodiment, a sealing groove for mounting the sealing assembly 6 is provided on the inner wall of the rolling wheel 33, and the second sealing member 62 is mounted in the sealing groove, thereby preventing the second sealing member 62 and the first sealing member 61 from moving axially.

[0055] In one embodiment of the sealing assembly 6, the connecting surfaces of the first sealing member 61 and the second sealing member 62 are configured as polished surfaces.

[0056] As shown in Figure 1 and Figure 3 In a preferred embodiment, the rolling wheel shaft 32 is connected to the rolling wheel arm 31 and the PDC assembly 4, respectively. As shown in Figure 1 The central axis of the rolling wheel shaft 32 is inclined relative to the central axis of the drill bit body 1, and the axial one end of the rolling wheel shaft 32 is fixedly connected to the rolling wheel arm 31, and the axial other end of the rolling wheel shaft 32 is connected to the PDC assembly 4 through the shaft seat 35. In this arrangement, the two axial ends of the rolling wheel shaft 32 are supported by the rolling wheel arm 31 and the PDC assembly 4, respectively, thereby enhancing the load-carrying capacity of the rolling wheel shaft 32.

[0057] Meanwhile, two sealing components 6 are respectively disposed at the two axial ends of the roller shaft 32. In the prior art, metal seals are usually used to improve the sealing life of the two axial ends of the roller shaft. However, during operation, because the pressure on the roller 33 is not perpendicular to the direction of the central axis of the roller shaft 32, the central axis of the roller 33 will be tilted at a certain angle to the central axis of the roller shaft 32. The sealing component 6 located at the end of the roller shaft 32 will be in a state where one end is subjected to a large radial compressive force, while the other is slightly compressed or even uncompressed, thus leading to seal failure. In this embodiment, the sealing component 6 is provided with a first sealing element 61 and a second sealing element 62 with different properties. During operation, the first sealing element 61, which has higher hardness, plays a supporting role and prevents the central axis of the roller 33 from being significantly offset from the central axis of the roller shaft 32. The second sealing element 62 has good elasticity and can ensure the sealing effect, so that both axial ends of the roller shaft 32 can achieve good sealing.

[0058] According to this invention, a plurality of roller teeth 34 are arranged along the circumferential surface of the roller 33, and are particularly evenly arranged. As the drill bit body 1 rotates, the roller 33 can break the formation rock through the roller teeth 34, thereby reducing the hardness of the formation rock.

[0059] In a preferred embodiment, such as Figure 1 As shown, the roller shaft 32 is connected to the drill bit body 1 via an elastic support ring 30. Specifically, the elastic support ring 30 is disposed within the shaft seat 35, and the roller shaft 32 is sleeved within the elastic support ring 30.

[0060] Furthermore, the elastic support ring 30 can be a ring with a grooved inner wall, a ring with a grooved outer wall, a ring with a hole in the middle of the ring wall, a ring with other structural gaps and combinations, or a wire-wound ring.

[0061] In this embodiment, the elastic support ring 30 ensures that the internal support force of the roller shaft 32 is continuous and effective, which greatly improves the stress and deformation state of the roller shaft 32, which is conducive to significantly improving the life of the roller 33, sealing assembly 6, etc., and thus improving the life of the PDC-roller hybrid drill bit 100.

[0062] According to this utility model, in a preferred embodiment, an oil bladder 311 and an oil channel 312 are provided inside the roller arm 31. The oil bladder 311 is filled with lubricating oil, and the oil channel 312 connects to the oil bladder 311. Furthermore, the oil in the oil bladder 311 can flow along the oil channel 312 to the contact surface between the roller shaft 32 and the roller 33. This arrangement reduces friction between the roller 33 and the roller shaft 32, extending the service life of the roller assembly 3. On the other hand, filling the gap between the roller 33 and the roller shaft 32 with oil prevents gravel from entering during operation and damaging the roller 33 or the roller shaft 32.

[0063] Further, the oil cup 315 is arranged in the roller arm 31 and is configured as a cylindrical barrel arranged in the roller arm 31, and the oil bag 311 is arranged in the oil cup 315. The balance hole 314 is arranged in the roller arm 31 and is configured to communicate the oil cup 315 with the outside. In this way, when the oil in the oil cup 315 is consumed during operation, the oil bag 311 is contracted under the action of atmospheric pressure, so that the oil in the oil cup 315 can flow smoothly between the roller shaft 32 and the rolling wheel 33.

[0064] In a preferred embodiment, the balance hole 314 communicates the space between the rolling wheel 33 and the roller arm 31 with the oil cup 315. As shown in the drawings, there is a space between the roller arm 31 and the rolling wheel 33, and the balance hole 314 communicates the oil bag 311 with the outside through the space, which on the one hand ensures that the oil bag 311 can work normally under atmospheric pressure, and on the other hand prevents the balance hole 314 from being blocked by rock cuttings during drilling. Figure 1

[0065] In a preferred embodiment, the oil cup 315 is arranged at a position deviating from the central axis of the drill bit body 1, so that the oil bag 311 deviates from the central axis of the drill bit body 1. In this arrangement, during drilling of the drill bit, the oil bag 311 and the oil therein are subjected to centrifugal force, and the oil bag 311 is self-adaptively deformed, 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.

[0066] Further, the oil channel 312 communicates the oil bag 311 to between the roller shaft 32 and the rolling wheel 33 from a position close to the outer side of the oil bag 311. That is, the connection point of the oil channel 312 with the oil bag 311 is located at a position close to the radial outer side of the drill bit body 1. In this arrangement, when the oil bag 311 is deformed under the action of centrifugal force, the oil in the oil bag 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.

[0067] In a specific embodiment, the end of the oil cup 315 away from the balance hole 314 is provided with a first plug 316, the first plug 316 is provided with an oil injection hole 317, the oil injection hole 317 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. In this way, when the oil in the oil bag 311 is insufficient, the oil injection plug 318 can be removed from the oil injection hole 317, and oil can be injected into the oil cup 315 through the oil injection hole 317. ​

[0068] The PDC assembly 4 comprises a blade 41 and cutting teeth 42 embedded under the blade 41, the cutting teeth 42 are arranged in a plurality, and the plurality of cutting teeth 42 are evenly arranged under the blade 41. Among them, the rolling 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 stratum. It can also be understood that the upper end edge of the cutting tooth 42 is located between the upper end edge of the rolling wheel tooth 34 and the upper end edge of the rolling wheel 33. It should be noted that the working end face here refers to the surface of the broken and cut rock, and the upper end edge here refers to the uppermost end in the axial direction of the PDC-rolling wheel hybrid drill bit 100.

[0069] In operation, the PDC-rolling wheel hybrid drill bit 100 rotates along its axis, and the working end face faces the stratum to be drilled. The rolling wheel assembly 3 can first pretreat and crush the rock of the stratum and form cracks and other defects in the unbroken stratum to reduce the crushing strength of the rock of the stratum, and then the PDC assembly 4 cuts the stratum rock which has been pre-crushed, full of cracks and weakened. That is, when the PDC-rolling wheel hybrid drill bit 100 rotates along its axis, the rolling wheel 33 rotates around the rolling wheel shaft 32 under the friction of the stratum. In the process of rotating, the rolling wheel tooth 34 is intermittently in contact with the stratum, so that the PDC-rolling wheel hybrid drill bit 100 generates periodic axial vibrations. Since the upper end edge of the rolling wheel tooth 34 is lower than the upper end edge of the cutting tooth 42, when the rolling wheel tooth 34 is in contact with the stratum, the cutting tooth 42 is not in contact with the stratum. At this time, the rolling wheel tooth 34 pretreats and crushes the stratum. When the rolling wheel 33 rotates to the position where the rolling wheel tooth 34 is not in contact with the stratum, the cutting tooth 42 is in contact with the stratum. At this time, the cutting tooth 42 cuts the stratum to periodically perform drilling work.

[0070] Therefore, on the one hand, the rolling wheel assembly 3 locally and partially crushes the bottom hole rock, and the working amount and stress are greatly reduced, and the setting of the oil pocket 311 and the oil channel 312 further reduces the friction between the rolling wheel 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 stratum rock, and the drillability of the stratum rock 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 can generate periodic axial vibrations and transmit to the drill string, effectively improving the stability of the working face of the directional well and the drilling pressure transmission efficiency, greatly improving the footage, the rate of penetration and the directional characteristics in the heterogeneous stratum, which is very beneficial to the speed-up and cost reduction of oil and gas field and mine exploration and development.

[0071] In a preferred embodiment, the tooth height of the rolling teeth 34 is set to be 0.01-5mm larger than the tooth height of the cutting teeth 42. Alternatively, the upper end edge wall of the rolling teeth 34 is set to be 0.01-5mm lower than the upper end edge wall of the cutting teeth 42. Within this range, the working efficiency is high.

[0072] In an embodiment, the connecting joint 2 at the lower end of the drill bit body 1 can be configured as a tapered connecting buckle, and is fixedly connected to 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 PDC-rolling hybrid drill bit 100 and the lower 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.

[0073] As shown in Figure 1 , the PDC assembly 4 and the rolling assembly 3 are arranged at the upper end of the drill bit body 1. Meanwhile, the PDC assembly 4 and the rolling assembly 3 are arranged as one or more. The one or more PDC assemblies 4 and the rolling 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 rolling assembly 3 can periodically and alternately perform cutting operations on the same position of the stratum.

[0074] In a preferred embodiment, the PDC assembly 4 and the rolling assembly 3 are arranged to be radially opposite.

[0075] In a preferred embodiment, a reinforcing layer is further coated on the outer wall of the rolling shaft 32, the rolling wheel 33 and the rolling arm 31. The reinforcing layer 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 rolling shaft 32, the rolling wheel 33 and the rolling 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 rolling shaft 32 and the rolling wheel 33, thereby further improving the service life of the rolling shaft 32 and the rolling wheel 33.

[0076] In a specific embodiment, the sealing surface of the shaft seat 35 and the rolling arm 31 and the rolling wheel 33 and the rolling 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 doing so, the friction is reduced, and the sealing between the end surface of the shaft seat 35 and the rolling wheel 33 and the sealing between the rolling wheel 33 and the rolling arm 31 are increased.

[0077] 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 to the outer wall of the drill bit body 1 by welding.

[0078] 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 upwardly. In this way, the rolling wheel 33 is directed towards the working end face.

[0079] In an embodiment, the profile line of the rolling wheel 33 is an arc-shaped line with a 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 formation rock. The rolling wheel 33 is installed below the roller shaft 32 and rotatably connected with the roller shaft 32.

[0080] 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 formation rock.

[0081] According to the present application, as shown in the drawings, Figure 1 As shown, the outer wall of the roller arm 31 is provided with first gauge teeth 332, which are embeddedly installed below the outer wall surface of the roller arm 31. Meanwhile, in a preferred embodiment, the rolling wheel 33 is also provided with roller gauge teeth 331 below the profile line at the radially outermost side. In this way, the first gauge teeth 332 and the roller gauge teeth 331 can effectively protect the hole diameter drilled by the PDC-roller hybrid drill bit 100 from being reduced during drilling, thereby ensuring the drilling performance and directional performance of the PDC-roller hybrid drill bit 100.

[0082] 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 gauge block 43 is provided with second gauge teeth 431 embeddedly installed below the gauge block 43.

[0083] The blade 41 is covered under the drill bit body 1, and the gauge block 43 is preferably integrally arranged with the blade 41. For example, a part of the radially outer side of the blade 41 is formed as the gauge block 43.

[0084] As shown in the drawings, Figure 1As shown, the active gauge teeth 44 can also be arranged under the gauge block 43, and the active gauge teeth 44 are arranged between the second gauge teeth 431 and the cutting teeth 42, and the maximum outer diameter of the active gauge teeth 44 is greater than or equal to the maximum outer diameter of the second gauge teeth 431. Thus, the first gauge teeth 332, the roller gauge teeth 331, the second gauge teeth 431 and the active gauge teeth 44 jointly act to effectively protect the hole diameter drilled by the PDC-roller hybrid drill bit 100 from being reduced during drilling, and further ensure the drilling performance and directional performance of the PDC-roller hybrid drill bit 100.

[0085] According to the utility model, the PDC assembly 4 is made of PDC (polycrystalline diamond compact) material. That is, the blade 41, the cutting teeth 42, the gauge block 43, the second gauge teeth 431 and the active gauge teeth 44 are all made of PDC (polycrystalline diamond compact) material. This can effectively ensure the strength of the PDC assembly 4, thereby ensuring the cutting performance of the PDC-roller hybrid drill bit 100.

[0086] Preferably, the cutting teeth 42 can be configured as plane teeth, conical teeth, ridge teeth and three-edged teeth and the like special-shaped teeth. This can further improve the cutting performance of the PDC-roller hybrid drill bit 100.

[0087] According to an embodiment of the utility model, as shown in the drawings, Figure 4 Preferably, the blade 41 can also be simultaneously provided with the second auxiliary cutting teeth 7. Similarly, the second auxiliary cutting teeth 7 are behind the cutting teeth 42, and the second auxiliary cutting teeth 7 and the first auxiliary cutting teeth 10 are distributed apart from each other in the radial direction. It should be understood that here, front and rear refer to the order of the cutting teeth 42 in contact with the stratum during rotation of the drill bit body 1, and behind the cutting teeth 42 refers to the side that lags behind the cutting teeth 42 in contact with the stratum rock.

[0088] The first auxiliary cutting teeth 10 and the second auxiliary cutting teeth 7 are made of hard alloy, ceramic or PDC material.

[0089] According to the utility model, as shown in the drawings, Figure 1As shown, the drill bit body 1 is internally provided with a center flow channel 8 extending in the axial direction and a nozzle 9. The center flow channel 8 in the drill bit body 1 is in communication 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 stratum rock surface aligned by the PDC-roller hybrid drill bit 100. On the 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 cuttings from being adhered under the roller 33 or the blade 41, and is very beneficial to improve the rate of penetration of the PDC-roller hybrid drill bit 100 and ensure the drilling performance of the PDC-roller hybrid drill bit 100.

[0090] A plurality of nozzles 9 can be provided in the drill bit body 1 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.

[0091] Embodiment Two:

[0092] In this embodiment, the structure of the roller 33, the roller shaft 32 and the PDC assembly 4 and the connection mode therebetween are different from those in Embodiment One, and are as follows.

[0093] In this embodiment, as shown in Figure 4 The first blind hole 333 and the second blind hole 334 have coinciding center axes, but the first blind hole 333 and the second blind hole 334 are not in communication with each other.

[0094] The roller shaft 32 is coaxially and rotatably arranged in the first blind hole 333, so that the roller 33 is rotatably connected with the roller shaft 32.

[0095] The first support shaft 45 is fixedly arranged on the drill bit body 1, the center axis of the first support shaft 45 coincides with the center axis of the roller shaft 32, and there is a gap between the first support shaft 45 and the roller shaft 32. The first support shaft 45 is coaxially and rotatably arranged in the second blind hole 334 of the roller 33, so that the roller 33 is rotatably connected with the PDC assembly 4.

[0096] According to Figure 4In the shown embodiment, the right axial part of the rolling wheel 33 is rotatably connected with the PDC assembly 4, and the left axial part of the rolling wheel 33 is rotatably connected with the roller shaft 32, that is, the left and right axial ends of the rolling wheel 33 are respectively supported by the roller shaft 32 and the PDC assembly 4, so that the stratum pressure received by the rolling wheel 33 during operation is dispersed to the PDC assembly 4 and the roller shaft 32, the strength of the force received by the roller shaft 32 is reduced, and the service life of the roller shaft 32 is prolonged. Further, after the force received by the roller shaft 32 is reduced, the internal sealing assembly 6 can be prevented from being damaged due to excessive inclination of the roller shaft 32, so that the service life of the rolling wheel 33 itself is prolonged.

[0097] For the structure of the first embodiment of the present application, the sealing assembly 6 needs to be arranged at both ends of the roller shaft 32. One of the functions of the sealing assembly 6 is to prevent leakage of lubricating oil between the roller shaft 32 and the rolling wheel 33. Therefore, failure of any one of the sealing assemblies 6 will cause leakage of lubricating oil, thereby reducing the reliability of the drill bit.

[0098] In contrast, according to the second embodiment of the present application, the rolling wheel 33 is rotatably connected with the roller shaft 32 by arranging the first blind hole 333 in the rolling wheel 33. Only the sealing assembly 6 (as shown in Figure 5 ) arranged at the position close to the outlet of the first blind hole 333 of the roller shaft 32 is needed to realize the sealing between the roller shaft 32 and the rolling wheel 33.

[0099] Therefore, according to the second embodiment of the present application, the number of sealing assemblies 6 on the roller shaft 32 can be reduced, and the probability of damage to the roller shaft 32 is naturally reduced, thereby improving the reliability of the drill bit.

[0100] As shown in Figure 5 In a preferred embodiment, the superhard coating 46 is arranged on the surface of the second blind hole 334 and the first supporting shaft 45. Through this arrangement, the contact surface of the second blind hole 334 and the first supporting shaft 45 can be more wear-resistant, and the stratum debris can also be prevented from entering between the second blind hole 334 and the first supporting shaft 45. 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.

[0101] As shown in Figure 5As shown, in a preferred embodiment, a sealing assembly 6 is arranged between the second blind hole 334 of the rolling wheel 33 and the first support shaft 45 of the PDC assembly 4. The specific structure of the sealing assembly 6 can refer to the structure in the first embodiment of the present application, which will not be described here. By arranging the sealing assembly 6, the lubricating oil can be stored between the second blind hole 334 and the first support shaft 45, thereby prolonging the service life of the second blind hole 334 and the first support shaft 45. In addition, the sealing assembly 6 can also prevent formation debris from entering between the second blind hole 334 and the first support shaft 45.

[0102] In the description of the present application, the description of the terms "one embodiment", "some embodiments", "example", "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 following terms does not necessarily refer to 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.

[0103] In the description of the present application, it should be understood that the terms "first", "second" are used for descriptive purposes only, 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 "multiple" is two or more, unless otherwise specifically limited.

[0104] 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, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium, or it can be the communication between two elements. For ordinary skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0105] Finally, it should be pointed out that the above description is only the preferred embodiment of the present application, and does not constitute any limitation on the present application. Although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement to some of the technical features. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A PDC-roller hybrid drill bit, comprising: a bit body (1) for connecting a drill string; a PDC assembly (4) arranged on the bit body; and a roller assembly (3) arranged on the bit body, the roller assembly comprising a roller arm (31) fixedly connected to the bit body, a roller shaft (32) arranged on the roller arm (31), a rolling wheel (33) rotatably arranged on the roller shaft (32), and a sealing assembly (6) arranged between the roller shaft (32) and the rolling wheel (33); wherein the sealing assembly (6) comprises a first sealing member (61) and a second sealing member (62), the first sealing member (61) has a higher hardness than the second sealing member (62), a seal is formed between the first sealing member (61) and the second sealing member (62), a dynamic seal is formed between the first sealing member (61) and the roller shaft (32), and a static seal is formed between the second sealing member (62) and the rolling wheel (33).

2. The PDC-roller hybrid drill bit of claim 1, wherein, A first blind hole (333) and a second blind hole (334) are respectively arranged at the axial ends of the rolling wheel (33), one end of the rolling wheel (33) is rotatably connected to the roller shaft (32) through the first blind hole (333), and the other end of the rolling wheel (33) is rotatably connected to a first support shaft (45) on the bit body (1) through the second blind hole (334).

3. The PDC-roller hybrid drill bit of claim 1, wherein, A static seal is formed between the radially outer side of the first sealing member (61) and the radially outer side of the second sealing member (62).

4. The PDC-roller hybrid drill bit of claim 1, wherein, The first sealing member (61) and the second sealing member (62) are in an integral structure.

5. The PDC-roller hybrid drill bit of claim 1, wherein, The first sealing member (61) has a higher wear resistance than the second sealing member (62).

6. The PDC-roller hybrid drill bit of claim 1, wherein, The first sealing member (61) has a lower friction than the second sealing member (62).

7. The PDC-roller hybrid drill bit of any of claims 1-6, wherein, An oil bag (311) and an oil channel (312) are arranged in the roller arm (31), the oil channel (312) is configured to enable oil in the oil bag (311) to flow to the contact surface of the roller shaft (32) and the rolling wheel (33).

8. The PDC-roller hybrid drill bit of claim 7, wherein, An oil cup (315) is arranged in the roller arm (31), the oil bag (311) is located in the oil cup (315), and a balance hole (314) is arranged in the roller arm (31) to communicate the oil cup (315) with the outside.

9. The PDC-roller hybrid drill bit of claim 8, wherein, The balance hole (314) communicates the space between the rolling wheel (33) and the roller arm (31) with the oil cup (315).

10. The PDC-roller hybrid drill bit of claim 9, wherein, A first plug (316) is arranged at the end of the oil cup (315) away from the balance hole (314), an oil injection hole (317) is formed in the first plug (316), and the oil injection hole (317) communicates with the inside of the oil bag (311).

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