A PDC-roller hybrid drill bit

Abstract

This invention belongs to the technical field of petroleum and geological drilling tools, specifically relating to a PDC-roller hybrid drill bit. The PDC-roller hybrid drill bit includes: a drill bit body; a roller assembly disposed in the roller area, the roller assembly including a roller arm fixedly connected to the drill bit body, a roller shaft fixedly connected to the roller arm, a rolling wheel disposed on the roller shaft, and at least one roller tooth disposed in the circumferential direction of the rolling wheel; and an oil cavity and oil passage disposed within the roller arm, the oil passage being configured to allow oil in the oil cavity to flow to the contact surface of the roller shaft and the rolling wheel; wherein, sealing components for sealing with the rolling wheel are provided at both ends of the roller shaft, the sealing components including composite sealing rings. This invention can significantly improve its service life, drilling footage, mechanical drilling rate, and directional characteristics in heterogeneous formations, which is beneficial for accelerating oil and gas field and mineral exploration and development and reducing costs.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of petroleum and geological drilling tools, and particularly relates to a PDC-roller hybrid drill bit. BACKGROUND

[0002] In the field of oil and gas drilling and geological drilling, a 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 the key to improving the rock breaking efficiency of complex formations, improving the drilling speed, and reducing the 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.

[0003] A PDC (polycrystalline diamond compact) drill bit can achieve good use effect in soft to medium-hard formations, and therefore is widely used in petroleum and geological drilling. However, in some medium to hard formations, especially in heterogeneous formations, the PDC drill bit has the problems of low mechanical drilling speed and insufficient service life. In directional wells, horizontal wells, extended reach wells, and branch wells, the PDC drill bit has the problem of unstable tool face, especially in the case of small hole deviation. Many times, a roller bit is needed to be used for orientation first, 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 small footage.

[0004] There is a PDC-roller hybrid drill bit in the prior art, which has the advantages of both PDC drill bits and roller bits, and the use of the drill bit has achieved certain results in improving the drilling speed and directional efficiency. However, the drill bit still has the problems of short service time, low service life, and premature failure of the roller part. SUMMARY

[0005] In view of the above technical problems, the present application aims to provide a PDC-roller hybrid drill bit, which can greatly improve the service life, footage, mechanical drilling speed, and directional characteristics in heterogeneous formations, and is beneficial to improving the drilling speed and reducing the cost of oil and gas field and mine exploration and development.

[0006] According to the present application, a PDC-roller hybrid drill bit is provided, comprising: a bit body, the bit body being divided into a roller region and a PDC region along a plane passing through an axis of the bit body; a roller assembly arranged in the roller region, the roller assembly comprising a roller arm fixedly connected with the bit body, a roller shaft fixedly connected with the roller arm, a rolling wheel arranged on the roller shaft, and at least one roller tooth arranged circumferentially on the rolling wheel; a PDC assembly arranged in the PDC region, the PDC assembly comprising a cutting tooth fixedly connected with the bit body for cutting; and an oil cavity and an oil channel arranged in the roller arm, the oil channel being configured to enable oil in the oil cavity to flow to a contact surface of the roller shaft and the rolling wheel; wherein a sealing assembly for sealing oil is arranged between the roller shaft and the rolling wheel, the sealing assembly comprising a composite sealing ring arranged at least one end of the roller shaft.

[0007] In one specific embodiment, the composite sealing ring comprises an inner ring and an outer ring arranged coaxially side by side, the hardness of the inner ring is greater than the hardness of the outer ring, and the friction resistance of the inner ring is lower than the friction resistance of the outer ring.

[0008] In one specific embodiment, the inner ring and the outer ring are arranged in an integrated manner.

[0009] In one specific embodiment, the inner ring and the outer ring are arranged in a split manner.

[0010] In one specific embodiment, the sealing assembly further comprises an elastic sealing ring sleeved on the roller shaft and axially abutting against the composite sealing ring, the elastic sealing ring is closer to an end of the roller shaft than the composite sealing ring.

[0011] In one specific embodiment, the sealing assembly further comprises an O-shaped sealing ring radially sleeved outside the inner ring.

[0012] In one specific embodiment, a sliding piston is arranged in the oil cavity, the sliding piston divides the oil cavity into an oil chamber and a balance chamber, the oil chamber is in communication with the oil channel, and the balance chamber is in communication with the outside.

[0013] In one specific embodiment, a first plug is arranged at an end of the oil chamber away from the sliding piston, an oil injection hole is formed in the first plug, and an oil injection plug is arranged in the oil injection hole.

[0014] In one specific embodiment, the oil channel comprises a first oil path, a second oil path, and a third oil path that are sequentially in communication, wherein,

[0015] the first oil path is arranged in the roller arm;

[0016] The second oil passage is arranged along the axial direction of the roller shaft, and one end of the second oil passage penetrates the roller shaft, and a second plug is arranged at the port of the second oil passage;

[0017] The third oil passage is arranged along the radial direction of the roller shaft.

[0018] In one specific embodiment, the lower end edge of the cutting tooth is located between the lower end edge of the roller tooth and the lower end edge of the rolling wheel.

[0019] Compared with the prior art, the application has the following advantages.

[0020] The PDC-rolling wheel hybrid drill bit according to the application combines a rolling wheel assembly and a PDC assembly, has high mechanical drilling speed and good tool face stability, and can significantly improve the mechanical drilling speed and footage, and achieve 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 mines.

[0021] In the working process of the PDC-rolling wheel hybrid drill bit, the roller teeth in the rolling wheel assembly first break the formation rock, form cracks and other defects in the unbroken formation, reduce the breaking strength of the formation rock, and then the cutting teeth in the PDC assembly cut. On the one hand, the roller teeth only pretreat the broken bottom hole rock, which greatly reduces the working load and stress. On the other hand, the cutting teeth in the PDC assembly cut the weakened formation rock, which greatly improves the drillability of the formation rock 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 roller teeth on the rolling wheel are arranged in a spaced manner, and the 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 PDC-rolling wheel hybrid drill bit during drilling, and is very beneficial to improving the drilling efficiency and enhancing the drilling effect.

[0022] The application sets lubricating oil at the contact position of the roller shaft and the rolling wheel, further prolongs the service life of the rolling assembly. And a composite sealing ring is arranged in the sealing assembly at both ends of the roller shaft, the sealing effect between the roller shaft and the rolling wheel is strengthened through the different properties of the inner and outer rings of the composite sealing ring, and the service life is prolonged. BRIEF DESCRIPTION OF DRAWINGS

[0023] The application will be described below with reference to the drawings.

[0024] Figure 1 The structure of the PDC-rolling wheel hybrid drill bit according to the application is schematically shown;

[0025] Figure 2 For Figure 1Enlarged structural schematic view of part A;

[0026] Figure 3 For Figure 2 Enlarged structural schematic view of part B;

[0027] Figure 4 Schematically shows Figure 1 Structure of working end face of the PDC-roller hybrid drill bit.

[0028] In the figure: 1, drill bit body; 11, roller area; 12, PDC area;

[0029] 2, connecting joint; 21, shackle groove;

[0030] 3, roller assembly; 301, first oil way; 302, second oil way; 303, third oil way; 31, roller arm; 311, oil cavity; 312, oil channel; 313, sliding piston; 314, balance chamber; 315, oil chamber; 316, first plug; 317, oil injection hole; 318, oil injection plug; 32, roller shaft; 323, second plug; 33, roller; 331, roller gauge-correcting tooth; 332, first gauge-correcting tooth; 34, roller tooth; 35, shaft seat;

[0031] 4, PDC assembly; 41, blade; 42, cutting tooth; 43, gauge block; 431, second gauge-correcting tooth; 44, active gauge-correcting tooth;

[0032] 6, sealing assembly; 61, outer ring; 62, elastic sealing ring; 63, inner ring; 64, O-shaped sealing ring;

[0033] 7, second auxiliary cutting tooth;

[0034] 8, central flow channel;

[0035] 9, nozzle;

[0036] 10, first auxiliary cutting tooth;

[0037] 100, PDC-roller hybrid drill bit.

[0038] 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 drawn according to the actual proportion. DETAILED DESCRIPTION

[0039] The present application will be described below by means of the drawings.

[0040] In the present application, it is to be noted that the directional phrases or limiting words "upper", "lower" and the like used in the present application are all with reference to the drawings referred to in the present application. Figure 1In other words, they are not used to define the absolute position of the components involved, but can vary depending on the specific circumstances.

[0041] Figure 1 The structure of the PDC-roller hybrid drill bit 100 according to the present invention is schematically shown. For example... Figure 1 As shown, the PDC-roller hybrid drill bit 100 includes a drill body 1, a roller assembly 3, and a PDC assembly 4. The drill body 1 is generally cylindrical, and a connecting joint 2 is constructed at the upper end of the drill body 1 for connecting to a drill string (not shown) that drives the drill body 1 to rotate. The drill body 1 is divided into two parts, a roller area 11 and a PDC area 12, by a plane through its axis. The roller assembly 3 is installed in the lower part of the roller area 11 and faces the working end face. In this embodiment, the roller assembly 3 includes a roller arm 31 fixedly connected to the drill body 1, a roller shaft 32 fixedly connected to the roller arm 31, a rolling wheel 33 mounted on the roller shaft 32, and roller teeth 34 embedded in the rolling wheel 33. The roller teeth 34 include at least one and are evenly arranged along the circumferential surface of the rolling wheel 33. An oil cavity 311 and an oil passage 312 are provided inside the roller arm 31. The oil cavity 311 is filled with lubricating oil, and the oil passage 312 connects to the oil cavity 311. The oil in the oil cavity 311 can flow along the oil passage 312 to the contact surface between the roller shaft 32 and the rolling wheel 33. This arrangement reduces friction between the rolling wheel 33 and the roller shaft 32, extending the service life of the roller assembly 3. Furthermore, filling the gap between the rolling wheel 33 and the roller shaft 32 with oil prevents debris from entering during operation and damaging either the rolling wheel 33 or the roller shaft 32. The PDC assembly 4 is located in the lower part of the PDC area 12 and faces the working end face. The PDC assembly 4 includes a cutter wing 41 and cutting teeth 42 embedded in the cutter wing 41. The lower edge of the cutting teeth 42 is located between the lower edge of the roller teeth 34 and the lower edge of the rolling wheel 33. Thus, the roller assembly 3 and the PDC assembly 4 form a PDC-roller hybrid drill bit 100. It should be noted that the working face here refers to the rock surface being broken and cut, and the lower edge here refers to the lowest point along the axial direction of the PDC-roller hybrid drill bit 100.

[0042] In operation, the PDC-roller hybrid drill bit 100 rotates along its axis with the working end facing the formation to be drilled. The roller assembly 3 can first pre-process and break the formation rock and form cracks and other defects in the unbroken formation to reduce the breaking strength of the formation rock, and then the PDC assembly 4 can cut the pre-broken, crack-filled and weakened formation rock. That is, when the PDC-roller hybrid drill bit 100 rotates along its axis, the rolling wheel 33 rotates around the roller shaft 32 due to the friction of the formation. In the process of rotation, the roller teeth 34 intermittently contact the formation, so that the PDC-roller hybrid drill bit 100 generates periodic axial vibrations. 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 contact the formation, the cutting teeth 42 do not contact the formation. At this time, the roller teeth 34 pre-process and break the formation. When the rolling wheel 33 rotates to the point where the roller teeth 34 do not contact the formation, the cutting teeth 42 contact the formation. At this time, the cutting teeth 42 cut the formation. Thus, the drilling operation is periodically performed.

[0043] Thus, on the one hand, the roller assembly 3 locally and partially breaks the bottom hole rock, and the working amount and stress are greatly reduced. In addition, the oil cavity 311 and the oil channel 312 are provided to further reduce the friction between the roller shaft 32 and the rolling wheel 33, thereby prolonging the service life. On the other hand, the cutting teeth 42 of the PDC assembly 4 cut the weakened formation rock, and the drillability of the formation rock is greatly improved, and the stress on the cutting teeth 42 is greatly improved, which greatly improves the service life of the roller assembly 3 and the PDC assembly 4. At the same time, the rolling of the rolling wheel 33 generates periodic axial vibrations and transmits 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 formation, and greatly reducing the cost of oil and gas field and mine exploration and development.

[0044] In a preferred embodiment, the lower end edge of the roller teeth 34 is 0.01-5mm lower than the lower end edge of the cutting teeth 42. In this vibration range, the working efficiency is high.

[0045] 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 to the drill string by a threaded connection. At the same time, the outer wall of the tapered connecting buckle is also circumferentially provided with a buckle releasing groove 21 for realizing the quick disassembly of the 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, which can significantly improve the disassembly efficiency.

[0046] The roller assembly 3 and the PDC assembly 4 can be distributed staggered or arranged adjacent to each other, and in a preferred embodiment, are arranged in a radial opposite distribution.

[0047] In one specific embodiment, as shown in Figure 2 The oil cavity 311 is in the shape of a cylinder. Inside the oil cavity 311 is a sliding piston 313 which is able to move along the axis of the oil cavity 311. The sliding piston 313 divides the oil cavity 311 into an oil liquid chamber 315 and a balance chamber 314. The oil liquid chamber 315 is filled with oil liquid and is in communication with the oil channel 312. The balance chamber 314 is in communication with the outside. In this way, when the oil liquid in the oil liquid chamber 315 is depleted during operation, the sliding piston 313 will move towards the oil liquid chamber 315 under the action of atmospheric pressure, thus ensuring that the oil liquid in the oil liquid chamber 315 can flow smoothly between the roller shaft 32 and the roller 33.

[0048] In one specific embodiment, the end of the oil liquid chamber 315 away from the sliding piston 313 is provided with a first plug 316. The first plug 316 is provided with an oil injection hole 317. An oil injection plug 318 is arranged in the oil injection hole 317. In this way, when the oil liquid in the oil liquid chamber 315 is depleted, the oil injection plug 318 can be removed from the oil injection hole 317, and oil liquid can be injected into the oil liquid chamber 315 through the oil injection hole 317.

[0049] In one preferred embodiment, the oil channel 312 includes a first oil passage 301 arranged in the roller arm 31, a second oil passage 302 arranged in the roller shaft 32, and a third oil passage 303. One end of the first oil passage 301 is in communication with the oil liquid chamber 315, and the other end is in communication with the second oil passage 302. The second oil passage 302 is arranged along the axis of the roller shaft 32. One end of the second oil passage 302 penetrates the roller shaft 32 to form an opening, and the other end is closed by the roller shaft 32. The end of the second oil passage 302 opening is provided with a second plug 323. The third oil passage 303 is arranged along the radial direction of the roller shaft 32, and is used to guide oil liquid to the contact surface between the roller shaft 32 and the roller 33. In this way, the processing of the oil channel 312 is facilitated, and only a simple drilling process is required.

[0050] In one specific embodiment, the roller assembly further includes a shaft seat 35. The shaft seat 35 is fixedly arranged on the drill bit body 1, and the end of the roller shaft 32 away from the roller arm 31 is arranged in the shaft seat 35. In this way, the stability of the roller shaft 32 is enhanced.

[0051] As shown in Figure 1 and Figure 2As shown in the figure, the roller shaft 32 is provided with a sealing assembly 6 for preventing oil leakage. The sealing assembly 6 includes two parts provided at the upper and lower ends of the roller shaft 32 for sealing with the rolling wheel 33. According to the present application, at least one of the two parts of the sealing assembly 6 provided at the upper and lower ends of the roller shaft 32 includes a composite sealing ring (the specific structure of the composite sealing ring of the present application will be described below). That is, if the lower end of the roller shaft 32 is provided with the composite sealing ring of the present application, the upper end of the roller shaft 32 can be provided with the composite sealing ring or the metal sealing ring of the prior art, as long as the sealing of one end of the roller shaft 32 adopts the composite sealing ring of the present application.

[0052] According to the present application, as Figure 3 As shown in the figure, the composite sealing ring includes an inner ring 63 and an outer ring 61, both of which are sleeved on the roller shaft 32 and arranged axially side by side. The two radial sides of the inner ring 63 and the outer ring 61 respectively abut against the roller shaft 32 and the rolling wheel 33, and the outer ring 61 is closer to the end of the roller shaft 32 than the inner ring 63. The inner ring 63 has higher hardness, lower friction and better wear resistance than the outer ring 61. The inner ring 63 is made of materials such as PTFE bronze, PTFE carbon fiber, PTFE glass fiber, PTFE red copper or PTFE brass, which have high hardness, good wear resistance and low friction. The outer ring 61 is made of materials such as nitrile rubber, saturated nitrile rubber or fluorine rubber, which have low hardness and good elasticity. Both the inner ring 63 and the outer ring 61 can play the role of supporting and sealing between the roller shaft 32 and the rolling wheel 33. The inner ring 63 mainly plays the role of supporting, and the outer ring 61 mainly plays the role of sealing, and the two mutually assist each other.

[0053] The inner ring 63 and the outer ring 61 of the composite sealing ring can be constructed as an integral structure or a split structure.

[0054] That is, the inner ring 63 and the outer ring 61 of the composite sealing ring can be combined as one part, and the inner ring 63 and the outer ring 61 are manufactured as one part during the manufacturing process of the composite sealing ring. Through this integral structure, the installation process can be more convenient.

[0055] Alternatively, the inner ring 63 and the outer ring 61 can be manufactured as two parts, which are used in the installation process. This split structure makes the part manufacturing more convenient.

[0056] During operation, the central axis of the rolling wheel 33 will be inclined to the central axis of the rolling shaft 32 due to the pressure applied to the rolling wheel 33, which is not perpendicular to the central axis of the rolling shaft 32. Therefore, the sealing assembly 6 at the end of the rolling shaft 32 will be subjected to a greater radial compression force at one end and a slight compression or even no compression at the other end. In the present embodiment, the composite sealing ring is provided with the inner ring 63 and the outer ring 61 with different properties. During operation, the inner ring 63 with higher hardness can prevent the central axis of the rolling wheel 33 from being greatly deviated from the central axis of the rolling shaft 32, and the outer ring 61 has good elasticity to ensure the sealing effect.

[0057] As shown in Figure 3 , the elastic sealing ring 62 is arranged at one axial end of the composite sealing ring. The composite sealing ring and the elastic sealing ring 62 are both sleeved on the rolling shaft 32 and axially abut each other. The elastic sealing ring 62 is close to the end of the rolling shaft 32, i.e., the elastic sealing ring 62 axially abuts the outer ring 61. In this way, the axial sealing of the composite sealing ring to the oil is strengthened.

[0058] In a specific embodiment, the shaft seat 35, the rolling arm 31, the sealing surface of 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, or boronizing, such as carburizing steel, or are made of ceramic materials. In this way, 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 rolling arm 31 are increased.

[0059] In a preferred embodiment, the sealing assembly 6 further comprises an O-shaped sealing ring 64. The O-shaped sealing ring 64 is sleeved on the inner ring 63 of the composite sealing ring and is located between the radial surface of the inner ring 63 and the contact surface of the rolling wheel 33. In this way, the sealing of the oil is further enhanced.

[0060] Specifically, in the present embodiment, as shown in Figure 3 , the O-shaped sealing ring 64 is sleeved on the radial outer side of the inner ring 63 to strengthen the radial sealing between the inner ring 63 and the rolling wheel 33. The thickness of the O-shaped sealing ring 64 is smaller than the axial thickness of the inner ring 63, so that the radial pressure between the rolling shaft 32 and the rolling wheel 33 is mainly borne by the inner ring 63. The elastic sealing ring 62 is arranged on the side of the outer ring 61 away from the inner ring 63, and the thickness of the elastic sealing ring 62 is smaller than the radial dimension of the outer ring 61 to strengthen the axial sealing effect.

[0061] According to the present application, as shown in Figure 1As shown, the roller arm 31 is fixedly connected to 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.

[0062] 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 toward the working end face.

[0063] In an embodiment, the profile line of the rolling wheel 33 is an arc line shape 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 mounted on the roller shaft 32 and forms a rotary connection with the roller shaft 32.

[0064] 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 form a rotary connection. 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 PDC-roller hybrid drill bit 100.

[0065] According to the present application, the roller teeth 34 are configured as first special-shaped teeth. The first special-shaped teeth can be in the form of a conical tooth, a wedge-shaped tooth, a spherical tooth, a spoon-shaped tooth, or an oval tooth, etc. The roller teeth 34 can be made of cemented carbide, ceramic, or PDC material. This can significantly improve the adaptability of the roller assembly 3 to the formation rock.

[0066] According to the present application, as shown, Figure 1 In a preferred embodiment, a first gauge protection tooth 332 is provided on the outer wall of the roller arm 31, and the first gauge protection tooth 332 is embeddedly mounted on the outer wall of the roller arm 31. At the same time, in a preferred embodiment, a roller gauge correction tooth 331 is also provided on the profile line of the rolling wheel 33 at the radially outermost side. In this way, the first gauge protection tooth 332 and the roller gauge correction tooth 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.

[0067] 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 a second gauge protection tooth 431 is provided in the gauge block 43 and embeddedly mounted on the gauge block 43.

[0068] The blade 41 is wrapped on 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.

[0069] like Figure 1 As shown, an active sizing tooth 44 can also be provided on the sizing block 43. The active sizing tooth 44 is located between the second sizing tooth 431 and the cutting tooth 42, and the maximum outer diameter of the active sizing tooth 44 is greater than or equal to the maximum outer diameter of the second sizing tooth 431. Thus, the first sizing tooth 332, the roller sizing tooth 331, the second sizing tooth 431, and the active sizing tooth 44 work together to effectively protect the diameter of the hole drilled by the PDC-roller hybrid drill bit 100 from shrinking during the drilling process, further ensuring the drilling performance and directional performance of the PDC-roller hybrid drill bit 100.

[0070] According to the present invention, the PDC component 4 is made of PDC (polycrystalline diamond composite) material. That is, the cutter wing 41, cutting teeth 42, gauge protection block 43, second gauge protection tooth 431, and active gauge protection tooth 44 are all made of PDC (polycrystalline diamond composite) material. This can effectively ensure the strength of the PDC component 4, thereby ensuring the cutting performance of the PDC-roller hybrid drill bit 100.

[0071] 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 PDC-roller hybrid drill bit 100.

[0072] According to one embodiment of the present invention, such as Figure 4 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.

[0073] Both the first auxiliary cutting tooth 10 and the second auxiliary cutting tooth 7 are made of cemented carbide, ceramic or PDC material.

[0074] According to the present invention, such as Figure 1As shown, the center flow channel 8 and the nozzle 9 are arranged in the interior of the drill bit body 1 and extend along the axial direction. The center flow channel 8 and the nozzle 9 pass through the drill bit body 1 and form a flow channel for the drilling fluid. The nozzle 9 is arranged 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 injected to the surface of the stratum rock aligned by the PDC-roller hybrid drill bit 100 through the center flow channel 8 and the nozzle 9. On one hand, the drilling fluid injected by the nozzle 9 can impact the stratum rock and soften the stratum rock. On the other hand, the drilling fluid injected by the nozzle 9 can clean the roller assembly 3 and the PDC assembly 4, effectively avoid the cuttings from being adhered to the roller 33 or the blade 41, and be 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.

[0075] A plurality of nozzles 9 can be arranged 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.

[0076] In the description of the present application, it should be understood that the terms "first", "second" are used only for the purpose of description and should not be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined as "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.

[0077] In the present application, unless otherwise specifically defined and limited, the terms "mounting", "connecting", "connecting", "fixing" and the like should be understood in a broad sense, for example, can be fixedly connected, can be detachably connected, or integrally connected; can be mechanically connected, or electrically connected; can be directly connected, or indirectly connected through an intermediate medium, or the internal communication of 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.

[0078] 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 present application, the illustrative description of the above 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.

[0079] Finally, it should be noted that the above only describes 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, those skilled in the art can still modify the technical solutions recorded in the foregoing embodiments or make equivalent replacements to some technical features thereof. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A PDC-roller hybrid drill bit, characterized by, The application relates to a drill bit body (1) which is divided into a roller section and a PDC section along a plane through the axis of the drill bit body (1); a roller assembly (3) is arranged in the roller section, the roller assembly (3) comprising 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) arranged on the roller shaft (32), and at least one roller tooth (34) arranged in the circumferential direction of the rolling wheel (33); a PDC assembly is arranged in the PDC section, the PDC assembly comprising a cutting tooth (42) fixedly connected with the drill bit body (1) and used for cutting; and an oil cavity (311) and an oil channel (312) are arranged in the roller arm (31), the oil channel (312) being configured to enable oil in the oil cavity (311) to flow to the contact surface of the roller shaft (32) and the rolling wheel (33). The oil cavity (311) is provided with a sliding piston (313), the sliding piston (313) divides the oil cavity (311) into an oil chamber (315) and a balance chamber (314), the oil chamber (315) is in communication with the oil channel (312), the balance chamber (314) is in communication with the outside, one end of the oil chamber (315) away from the sliding piston (313) 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 provided with an oil injection plug (318), after the oil in the oil chamber (315) is consumed in the working process, the sliding piston (313) moves towards the oil chamber under the action of atmospheric pressure, so that the oil in the oil chamber can flow to the space between the roller shaft and the rolling wheel. A sealing assembly for sealing oil is arranged between the roller shaft (32) and the rolling wheel (33), the sealing assembly comprising a composite sealing ring arranged at least one end of the roller shaft (32), and an elastic sealing ring (62) sleeved on the roller shaft (32) and axially abutting against the composite sealing ring, the elastic sealing ring (62) being closer to the end of the roller shaft (32) than the composite sealing ring. The composite sealing ring comprises an inner ring (63) and an outer ring (61) arranged coaxially and side by side, the hardness of the inner ring (63) is greater than that of the outer ring, and the friction resistance of the inner ring (63) is lower than that of the outer ring (61). The inner ring (63) and the outer ring (61) are arranged in an integrated mode. The inner ring (63) and the outer ring (61) are arranged in a split mode. The sealing assembly further comprises an O-shaped sealing ring (64) radially sleeved outside the inner ring (63).

2. The PDC-roller hybrid drill bit of claim 1, wherein, The oil channel (312) comprises a first oil path (301), a second oil path (302) and a third oil path (303) which are sequentially communicated, wherein 3. The PDC-roller hybrid drill bit of claim 2, wherein, The first oil path (301) is arranged in the roller arm (31).

4. The PDC-roller hybrid drill bit of claim 2, wherein, ​ 5. The PDC-roller hybrid drill bit of any one of claims 2-4, wherein, ​ 6. The PDC-roller hybrid drill bit of any one of claims 1-4, wherein, ​ ​ The second oil passage (302) is arranged along the axial direction of the roller shaft (32), and one end of the second oil passage (302) penetrates the roller shaft (32), and a second plug (323) is arranged at the port of the second oil passage (302); The third oil passage (303) is arranged along the radial direction of the roller shaft (32).

7. The PDC-roller hybrid drill bit of any one of claims 1-4, wherein, The lower end edge of the cutting tooth (42) is located between the lower end edge of the roller tooth (34) and the lower end edge of the rolling wheel (33).

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