Drillable drill bit

Abstract

The invention belongs to the technical field of drilling tools, and particularly relates to a drillable drill bit. The drillable drill bit includes: a sleeve; and the core body is made of a drillable material and is fixedly arranged at the end part of the sleeve. The drilling time can be saved.

Description

Technical Field

[0001] The invention belongs to the technical field of drilling tools, and in particular, relates to a drillable drill bit. Background Art

[0002] In the current drilling operation process, there is a demand for casing drilling. Casing drilling refers to a drilling technology that uses casing instead of drill pipe to apply torque and drilling pressure to the drill bit, drive the drill bit to rotate and drill, drill to the designed well depth without starting, and directly cement the well.

[0003] In the existing casing drilling operation, the entire drilling process no longer uses drill rods, drill collars, etc. During the operation, wire ropes are used to cast and fish, and the drill bit is replaced or pulled out in the casing. The casing drill bit itself can rotate with the casing, and the pressure and rotational force exerted by the cooperation of the casing and other structures can crush the contacted strata or rocks to achieve the drilling effect.

[0004] However, this operation method requires a lot of auxiliary time to cast and retrieve the drill bit, and the operation is more complicated, which is not conducive to increasing speed and efficiency. Summary of the invention

[0005] In view of the above-mentioned technical problems, the present invention aims to provide a drillable drill bit to save drilling time.

[0006] According to the present invention, there is provided a drillable drill bit, comprising:

[0007] Sleeve;

[0008] The core body is made of a drillable material and is fixedly arranged at the end of the sleeve.

[0009] In a preferred embodiment, the core body includes a plurality of first blades arranged at intervals along the circumferential direction, and a first flow channel is formed between any two adjacent first blades.

[0010] In a preferred embodiment, a plurality of first cutting teeth and first gauge teeth are provided on the first blade wing. The plurality of first cutting teeth and first gauge teeth cover the generatrix of the first blade wing, and the number of covering layers of the first cutting teeth and the first gauge teeth on each first blade wing is set to 1 to 10 layers.

[0011] In a preferred embodiment, the core body is made of aluminum alloy or copper alloy, and the first cutting teeth and the first gauge teeth are arranged on the first blade by cold inserting.

[0012] In a preferred embodiment, a mounting hole for mounting the first cutting tooth and the first gauge tooth is provided on the first blade, and the first cutting tooth and the first gauge tooth are fixed in the mounting hole of the first blade by interference fit or by interference fit combined with gluing. The surface of the first blade is strengthened by cold coating ceramic glue, the ceramic glue includes ceramic powder and resin glue, wherein the ceramic powder can be silicon carbide, silicon nitride, tungsten carbide, etc.

[0013] In a preferred embodiment, the core is connected to the sleeve via a torque transmission mechanism.

[0014] In a preferred embodiment, the torque transmission mechanism is configured as a thread.

[0015] In a preferred embodiment, the torque transmission mechanism includes a fixing member, the core body enters into the sleeve along the axial direction, and the core body and the sleeve are fixed by a radially arranged fixing member.

[0016] In a preferred embodiment, a core hole is coaxially arranged at one end of the core body close to the sleeve, and a nozzle is arranged in the core body. Both ends of the nozzle are respectively connected to the core hole and the first flow channel, and the central axis of the nozzle is inclined relative to the central axis of the core body.

[0017] In a preferred embodiment, the sleeve includes a plurality of second blades uniformly distributed at intervals along the circumference, a second flow channel is set between two adjacent second blades, and a plurality of second cutting teeth and second gauge teeth are set on the second blade. The plurality of second cutting teeth and second gauge teeth are low-temperature silver-welded to the second blade and cover the generatrix of the second blade, and the surface of the second blade is strengthened by surfacing tungsten carbide.

[0018] Compared with the prior art, the advantages of the present application are as follows.

[0019] The drillable drill bit of the present invention comprises a sleeve and a core body arranged at the end of the sleeve, wherein the core body is made of a drillable material. Under this arrangement, it is not necessary to use a wire rope to cast and fish the drill bit, and the drill bit can be directly drilled out by drilling out, thereby saving a lot of time and improving drilling efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The present invention will be described below with reference to the accompanying drawings.

[0021] Figure 1 A schematic diagram showing a first embodiment of a drillable drill bit according to the present invention is shown;

[0022] Figure 2 A schematic diagram showing a second embodiment of a drillable drill bit according to the present invention;

[0023] Figure 3 A schematic diagram showing a third embodiment of a drillable drill bit according to the present invention;

[0024] Figure 4 A schematic diagram of a fourth embodiment of a drillable drill head according to the present invention is shown.

[0025] In the figure: 1, sleeve; 2, core body; 3, second blade; 4, first blade; 5, second flow channel; 6, first flow channel; 7, first cutting tooth; 8, second cutting tooth; 9, first gauge tooth; 10, second gauge tooth; 11, nozzle; 12, torque transmission mechanism; 13, core hole; 14, through hole; 15, joint; 16, fixing piece; 100, drillable drill bit.

[0026] In the present application, all drawings are schematic drawings, which are only used to illustrate the principles of the present invention and are not drawn according to the actual scale. DETAILED DESCRIPTION

[0027] The present invention will be described below with reference to the accompanying drawings.

[0028] It should be noted that the directional terms or qualifiers "upper" and "lower" used in this application are all directed to the referenced Figure 1 They are not intended to define the absolute positions of the components involved, but may vary depending on the specific circumstances.

[0029] Embodiment 1:

[0030] Figure 1 1 shows the structure of a first embodiment of a drillable drill bit 100 according to the present invention. Figure 1 As shown, the drillable drill bit 100 comprises a sleeve 1 and a core 2, and the core 2 is coaxially fixedly arranged at the end of the sleeve 1. According to the present invention, the core 2 is made of a drillable material. With this arrangement, there is no need to use a wire rope to fish the drill bit, and the core 2 can be directly drilled out by drilling out, so that the oil and gas well can be unblocked and the next opening operation can be carried out.

[0031] In a specific embodiment, the core 2 is made of drillable aluminum alloy or copper alloy material. It is easy to understand that the drillable aluminum alloy or copper alloy material is a prior art, and its specific composition is not the technical point of the present invention, and will not be repeated here.

[0032] In a preferred embodiment, the sleeve 1 is made of alloy steel materials such as 40CrMnMoA, 42CrMo, etc. During the drilling process, the outer diameter of the drilling tool is smaller than the inner diameter of the sleeve 1, and the drilling tool can be inserted into the sleeve 1 to directly drill the core 2. The material used for the sleeve 1 in this embodiment makes the sleeve 1 high in strength, thereby improving the overall strength of the drillable drill bit 100 of the present invention.

[0033] In a specific embodiment, Figure 1 As shown, the sleeve 1 includes a joint 15, a through hole portion 14 and a torque transmission mechanism 12, wherein the inner diameters of the joint 15 and the torque transmission mechanism 12 are both larger than the inner diameter of the through hole portion 14. The core 2 is adapted to the torque transmission mechanism 12, and the lower end of the core 2 extends into the interior of the torque transmission mechanism 12 until the lower end of the core 2 abuts against the upper end of the through hole portion 14.

[0034] In this embodiment, the torque transmission mechanism 12 is a thread, that is, an external thread is provided on the outer wall of the core body 2, and an internal thread is provided on the inner wall of the sleeve 1, and the core body 2 and the sleeve 1 are fixed to each other by threaded connection.

[0035] According to the present invention, the core 2 includes a plurality of first blades 4 arranged at intervals along the circumferential direction, and each first blade 4 extends from the axial end of the overall structure of the core 2 to the side. A first flow channel 6 is provided between any two adjacent first blades 4 .

[0036] In a preferred embodiment, a ceramic glue is cold-coated on the surface of the first blade 4 for strengthening. The ceramic glue includes ceramic powder and resin glue, which are uniformly mixed to form ceramic glue. The ceramic powder can be silicon carbide, silicon nitride, tungsten carbide, etc.

[0037] A plurality of first cutting teeth 7 and first gauge teeth 9 are arranged on the first blade wing 4. The first cutting teeth 7 are arranged on the first blade wing 4 corresponding to the axial end of the core body 2, and the first gauge teeth 9 are arranged on the first blade wing 4 corresponding to the side of the core body 2.

[0038] The first cutting teeth 7 and the first gauge teeth 9 cover the generatrix of the first blade wing 4, that is, the first cutting teeth 7 and the first gauge teeth 9 are arranged in sequence along the generatrix of the first blade wing 4, and the number of covering layers of the first cutting teeth 7 and the first gauge teeth 9 on each first blade wing 4 is greater than 1 and less than or equal to 10 layers.

[0039] In a preferred embodiment, the top surface and side surfaces of the first blade 4 are sprayed with superhard material by plasma spraying, laser spraying or high velocity oxygen fuel (HVOF) spraying, and are strengthened by oxidation or the like.

[0040] In a preferred embodiment, the top surface and side surfaces of the first blade wing 4 are reinforced by applying ceramic glue or the like.

[0041] In a specific embodiment, a center hole 13 is coaxially arranged at one end of the core body 2 close to the sleeve 1, and a nozzle 11 is arranged inside the core body 2. The two ends of the nozzle 11 are respectively connected to the center hole 13 and the first flow channel 6, and the central axis of the nozzle 11 is inclined relative to the central axis of the core body 2.

[0042] Furthermore, the nozzle 11 is made of drillable copper alloy, ceramic, aluminum alloy, or a combination of copper alloy and ceramic.

[0043] Furthermore, the nozzle 11 is arranged to cover the bottom hole generatrix. In other words, the nozzle 11 and the central axis of the core body 2 have overlapping parts.

[0044] In this embodiment, if Figure 1 As shown, the sleeve 1 includes a plurality of second blades 3 uniformly distributed at intervals along the circumference, and the top of the second blade 3 is set to be arc-shaped, that is, the diameter of the top area of ​​the second blade 3 gradually decreases from bottom to top. A second flow channel 5 is set between two adjacent second blades 3.

[0045] In a preferred embodiment, tungsten carbide is built-up on the surface of the second blade wing 3, thereby strengthening the second blade wing 3.

[0046] A plurality of second cutting teeth 8 and second gauge teeth 10 are arranged on the second blade wing 3. The second cutting teeth 8 are arranged on the top arc region of the second blade wing 3. The second gauge teeth 10 are arranged on the side of the second blade wing 3 and are located below the arc region of the second blade wing 3.

[0047] The second cutting teeth 8 and the second gauge teeth 10 are low temperature silver-welded to the second blade wing 3 and cover the generatrix of the second blade wing 3. In other words, the second cutting teeth 8 and the second gauge teeth 10 are distributed along the generatrix of the second blade wing 3.

[0048] Furthermore, the top surface and side surfaces of the second blade wing 3 are strengthened by surfacing, plasma spraying, laser spraying, and the like.

[0049] In this embodiment, the first cutting teeth 7, the second cutting teeth 8, the first gauge teeth 9, and the second gauge teeth 10 are made of any superhard material such as thermally stable polycrystalline diamond (TSP), PDC composite sheet, cemented carbide, ceramic, cubic boron nitride, etc.

[0050] In a specific embodiment, the outer diameter of the first gauge teeth 9 on the first blade wing 4 is smaller than the outer diameter of the second gauge teeth 10 on the second blade wing 3 .

[0051] In this embodiment, the working principle of the drillable drill bit 100 is as follows. The joint 15 is connected to the casing (not shown in the figure) of the casing drilling process. During the drilling process, the drilling fluid flows into the annulus along the casing through the through-hole portion 14, the core hole 13, the nozzle 11, the first flow channel 6, and the second flow channel 5 in sequence. The drilling pressure of the casing is transmitted to the core body 2 through the sleeve 1. The first cutting teeth 7 on the core body 2 and the drilling fluid of the nozzle 11 are combined to break the formation to form a small wellbore at the bottom of the well, release the formation pressure at the bottom of the well, and enhance the drillability of the formation. Then the second cutting teeth 8 on the sleeve 1 are combined with the return drilling fluid to break the rock near the well wall to form a wellbore of the designed diameter. The mechanical and hydraulic combined rock breaking is conducive to improving the mechanical drilling speed. After the drillable drill bit 100 of the present invention drills to the designed well depth, there is no need to salvage the drill bit, and cement is directly injected to cement the well, which simplifies the cementing procedure and saves the completion auxiliary time. When the next process is carried out, the drill bit is directly lowered to drill out the drillable drill bit 100 of the present invention, and then the new well section is drilled, which greatly simplifies the casing drilling process, improves downhole safety, and saves drilling costs.

[0052] Embodiment 2:

[0053] Figure 1 1 shows the structure of a first embodiment of a drillable drill bit 100 according to the present invention. Figure 1 As shown, the drillable drill bit 100 comprises a sleeve 1 and a core 2, and the core 2 is coaxially fixedly arranged at the end of the sleeve 1. According to the present invention, the core 2 is made of a drillable material. With this arrangement, there is no need to use a wire rope to fish the drill bit, and the core 2 can be directly drilled out by drilling out, so that the oil and gas well can be unblocked and the next opening operation can be carried out.

[0054] In a specific embodiment, the core 2 is made of drillable aluminum alloy or copper alloy material. It is easy to understand that the drillable aluminum alloy or copper alloy material is a prior art, and its specific composition is not the technical point of the present invention, and will not be repeated here.

[0055] In a preferred embodiment, the sleeve 1 is made of alloy steel materials such as 40CrMnMoA, 42CrMo, etc. During the drilling process, the outer diameter of the drilling tool is smaller than the inner diameter of the sleeve 1, and the drilling tool can be inserted into the sleeve 1 to directly drill the core 2. The material used for the sleeve 1 in this embodiment makes the sleeve 1 high in strength, thereby improving the overall strength of the drillable drill bit 100 of the present invention.

[0056] In a specific embodiment, Figure 1As shown, the sleeve 1 includes a joint 15, a through hole portion 14 and a torque transmission mechanism 12, wherein the inner diameters of the joint 15 and the torque transmission mechanism 12 are both larger than the inner diameter of the through hole portion 14. The core 2 is adapted to the torque transmission mechanism 12, and the lower end of the core 2 extends into the interior of the torque transmission mechanism 12 until the lower end of the core 2 abuts against the upper end of the through hole portion 14.

[0057] In this embodiment, the torque transmission mechanism 12 includes a fixing member 16. Specifically, the core 2 is inserted or screwed into the sleeve 1 along the axial direction until the lower end of the core 2 abuts against the upper end of the through hole portion 14, and then the core 2 and the sleeve 1 are fixed by the radially arranged fixing member 16. Further, the fixing member 16 can be a screw or a pin.

[0058] In a preferred embodiment, the core 2 is axially inserted into the sleeve 1 by key connection, spline connection or polygonal prism connection. Specifically, mutually matching keys and keyways, or mutually matching splines and splineways, or mutually matching polygons are provided between the outer wall of the core 2 and the inner wall of the sleeve 1. After the core 2 is inserted into place, the core 2 is fixed to the sleeve 1 in the radial direction by screws or pins.

[0059] According to the present invention, the core 2 includes a plurality of first blades 4 that are evenly spaced along the circumference, and each first blade 4 extends from the axial end of the overall structure of the core 2 to the side. A first flow channel 6 is provided between any two adjacent first blades 4 .

[0060] A plurality of first cutting teeth 7 and first gauge teeth 9 are arranged on the first blade wing 4. The first cutting teeth 7 are arranged on the first blade wing 4 corresponding to the axial end of the core body 2, and the first gauge teeth 9 are arranged on the first blade wing 4 corresponding to the side of the core body 2.

[0061] In a preferred embodiment, the top surface and side surfaces of the first blade 4 are sprayed with superhard material by plasma spraying, laser spraying or high velocity oxygen fuel (HVOF) spraying, and are strengthened by oxidation or the like.

[0062] In a preferred embodiment, the top surface and side surfaces of the first blade wing 4 are reinforced by applying ceramic glue or the like.

[0063] In a specific embodiment, a center hole 13 is coaxially arranged at one end of the core body 2 close to the sleeve 1, and a nozzle 11 is arranged inside the core body 2. The two ends of the nozzle 11 are respectively connected to the center hole 13 and the first flow channel 6, and the central axis of the nozzle 11 is inclined relative to the central axis of the core body 2.

[0064] Furthermore, the nozzle 11 is made of drillable copper alloy, ceramic, aluminum alloy, or a combination of copper alloy and ceramic.

[0065] Furthermore, the nozzle 11 is arranged to cover the bottom hole generatrix. In other words, the nozzle 11 and the central axis of the core body 2 have overlapping parts.

[0066] In this embodiment, if Figure 1 As shown, the sleeve 1 includes a plurality of second blades 3 uniformly distributed at intervals along the circumference, and the top of the second blade 3 is set to be arc-shaped, that is, the diameter of the top area of ​​the second blade 3 gradually decreases from bottom to top. A second flow channel 5 is set between two adjacent second blades 3.

[0067] A plurality of second cutting teeth 8 and second gauge teeth 10 are arranged on the second blade wing 3. The second cutting teeth 8 are arranged on the top arc region of the second blade wing 3. The second gauge teeth 10 are arranged on the side of the second blade wing 3 and are located below the arc region of the second blade wing 3.

[0068] Furthermore, the top surface and side surfaces of the second blade wing 3 are strengthened by surfacing, plasma spraying, laser spraying, and the like.

[0069] In this embodiment, the first cutting teeth 7, the second cutting teeth 8, the first gauge teeth 9, and the second gauge teeth 10 are made of any superhard material such as thermally stable polycrystalline diamond (TSP), PDC composite sheet, cemented carbide, ceramic, cubic boron nitride, etc.

[0070] In a specific embodiment, the outer diameter of the first gauge teeth 9 on the first blade wing 4 is smaller than the outer diameter of the second gauge teeth 10 on the second blade wing 3 .

[0071] In this embodiment, the working principle of the drillable drill bit 100 is as follows. The joint 15 is connected to the casing (not shown in the figure) of the casing drilling process. During the drilling process, the drilling fluid flows into the annulus along the casing through the through-hole portion 14, the core hole 13, the nozzle 11, the first flow channel 6, and the second flow channel 5 in sequence. The drilling pressure of the casing is transmitted to the core body 2 through the sleeve 1. The first cutting teeth 7 on the core body 2 and the drilling fluid of the nozzle 11 are combined to break the formation to form a small wellbore at the bottom of the well, release the formation pressure at the bottom of the well, and enhance the drillability of the formation. Then the second cutting teeth 8 on the sleeve 1 are combined with the return drilling fluid to break the rock near the well wall to form a wellbore of the designed diameter. The mechanical and hydraulic combined rock breaking is conducive to improving the mechanical drilling speed. After the drillable drill bit 100 of the present invention drills to the designed well depth, there is no need to salvage the drill bit, and cement is directly injected to cement the well, which simplifies the cementing procedure and saves the completion auxiliary time. When the next process is carried out, the drill bit is directly lowered to drill out the drillable drill bit 100 of the present invention, and then the new well section is drilled, which greatly simplifies the casing drilling process, improves downhole safety, and saves drilling costs.

[0072] Embodiment three:

[0073] Figure 11 shows the structure of a first embodiment of a drillable drill bit 100 according to the present invention. Figure 1 As shown, the drillable drill bit 100 comprises a sleeve 1 and a core 2, and the core 2 is coaxially fixedly arranged at the end of the sleeve 1. According to the present invention, the core 2 is made of a drillable material. With this arrangement, there is no need to use a wire rope to fish the drill bit, and the core 2 can be directly drilled out by drilling out, so that the oil and gas well can be unblocked and the next opening operation can be carried out.

[0074] In a specific embodiment, the core 2 is made of drillable aluminum alloy or copper alloy material. It is easy to understand that the drillable aluminum alloy or copper alloy material is a prior art, and its specific composition is not the technical point of the present invention, and will not be repeated here.

[0075] In a preferred embodiment, the sleeve 1 is made of alloy steel materials such as 40CrMnMoA, 42CrMo, etc. During the drilling process, the outer diameter of the drilling tool is smaller than the inner diameter of the sleeve 1, and the drilling tool can be inserted into the sleeve 1 to directly drill the core 2. The material used for the sleeve 1 in this embodiment makes the sleeve 1 high in strength, thereby improving the overall strength of the drillable drill bit 100 of the present invention.

[0076] In a specific embodiment, Figure 1 As shown, the sleeve 1 includes a joint 15, a through hole portion 14 and a torque transmission mechanism 12, wherein the inner diameters of the joint 15 and the torque transmission mechanism 12 are both larger than the inner diameter of the through hole portion 14. The core 2 is adapted to the torque transmission mechanism 12, and the lower end of the core 2 extends into the interior of the torque transmission mechanism 12 until the lower end of the core 2 abuts against the upper end of the through hole portion 14.

[0077] In this embodiment, the torque transmission mechanism 12 is a thread, that is, an external thread is provided on the outer wall of the core body 2, and an internal thread is provided on the inner wall of the sleeve 1, and the core body 2 and the sleeve 1 are fixed to each other by threaded connection.

[0078] According to the present invention, the core 2 includes a plurality of first blades 4 that are evenly spaced along the circumference, and each first blade 4 extends from the axial end of the overall structure of the core 2 to the side. A first flow channel 6 is provided between any two adjacent first blades 4 .

[0079] A plurality of first cutting teeth 7 and first gauge teeth 9 are arranged on the first blade wing 4. The first cutting teeth 7 are arranged on the first blade wing 4 corresponding to the axial end of the core body 2, and the first gauge teeth 9 are arranged on the first blade wing 4 corresponding to the side of the core body 2.

[0080] In a preferred embodiment, the top surface and side surfaces of the first blade 4 are sprayed with superhard material by plasma spraying, laser spraying or high velocity oxygen fuel (HVOF) spraying, and are strengthened by oxidation or the like.

[0081] In a preferred embodiment, the top surface and side surfaces of the first blade wing 4 are reinforced by applying ceramic glue or the like.

[0082] In a specific embodiment, a center hole 13 is coaxially arranged at one end of the core body 2 close to the sleeve 1, and a nozzle 11 is arranged inside the core body 2. The two ends of the nozzle 11 are respectively connected to the center hole 13 and the first flow channel 6, and the central axis of the nozzle 11 is inclined relative to the central axis of the core body 2.

[0083] Furthermore, the nozzle 11 is made of drillable copper alloy, ceramic, aluminum alloy, or a combination of copper alloy and ceramic.

[0084] Furthermore, the nozzle 11 is arranged to cover the bottom hole generatrix. In other words, the nozzle 11 and the central axis of the core body 2 have overlapping parts.

[0085] In this embodiment, if Figure 1 As shown, the sleeve 1 includes a plurality of second blades 3 uniformly distributed at intervals along the circumference, and the top of the second blade 3 is set to be arc-shaped, that is, the diameter of the top area of ​​the second blade 3 gradually decreases from bottom to top. A second flow channel 5 is set between two adjacent second blades 3.

[0086] A plurality of second cutting teeth 8 and second gauge teeth 10 are arranged on the second blade wing 3. The second cutting teeth 8 are arranged on the top arc region of the second blade wing 3. The second gauge teeth 10 are arranged on the side of the second blade wing 3 and are located below the arc region of the second blade wing 3.

[0087] Furthermore, the top surface and side surfaces of the second blade wing 3 are strengthened by surfacing, plasma spraying, laser spraying, and the like.

[0088] In this embodiment, the first cutting teeth 7 and the first gauge teeth 9 are made of thermally stable polycrystalline diamond (TSP), and the second cutting teeth 8 and the second gauge teeth 10 are made of PDC composite sheets.

[0089] In this embodiment, the first cutting teeth 7 and the first gauge teeth 9 are arranged on the first blade wing 4 by cold insertion. Specifically, a mounting hole for mounting the first cutting teeth 7 and the first gauge teeth 9 is arranged on the first blade wing 4, and the first cutting teeth 7 and the first gauge teeth 9 are fixed in the mounting hole of the first blade wing 4 by interference fit, or by a combination of interference fit and adhesive. The size of the first cutting teeth 7 and the first gauge teeth 9 protruding from the surface of the first blade wing 4 is ≤2mm, and they are inserted by cold insertion process, avoiding the deficiency of the existing hot insertion and brazing process causing a significant decrease in the strength of the aluminum alloy.

[0090] In a specific embodiment, the outer diameter of the first gauge teeth 9 on the first blade wing 4 is smaller than the outer diameter of the second gauge teeth 10 on the second blade wing 3 .

[0091] In this embodiment, the working principle of the drillable drill bit 100 is as follows. The joint 15 is connected to the casing (not shown in the figure) of the casing drilling process. During the drilling process, the drilling fluid flows into the annulus along the casing through the through-hole portion 14, the core hole 13, the nozzle 11, the first flow channel 6, and the second flow channel 5 in sequence. The drilling pressure of the casing is transmitted to the core body 2 through the sleeve 1. The first cutting teeth 7 on the core body 2 and the drilling fluid of the nozzle 11 are combined to break the formation to form a small wellbore at the center of the bottom of the well, release the formation pressure at the bottom of the well, and enhance the drillability of the formation. Mechanical and hydraulic combined rock breaking is conducive to improving the mechanical drilling speed. After the drillable drill bit 100 of the present invention drills to the designed well depth, there is no need to salvage the drill bit, and cement is directly injected to cement the well, which simplifies the cementing procedure and saves completion auxiliary time. When the next process is carried out, the drill bit is directly lowered to drill out the drillable drill bit 100 of the present invention, and then the new well section is drilled, which greatly simplifies the casing drilling process, improves downhole safety, and saves drilling costs.

[0092] Embodiment four:

[0093] This embodiment is based on the third embodiment, and the torque transmission mechanism 12 (thread) of the third embodiment is replaced by the torque transmission mechanism 12 of the second embodiment (a connecting structure in which the core body 2 is axially inserted or screwed into the sleeve 1 and fixed by screws or pins), and the remaining structures are the same as those of the third embodiment and will not be repeated here.

[0094] In the description of the present invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0095] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0096] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0097] Finally, it should be noted that the above is only a preferred embodiment of the present invention and does not constitute any limitation to the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for a person skilled in the art to modify the technical solutions described in the aforementioned embodiments or to replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A drillable drill bit, characterized in that: include: Sleeve (1); The core body (2) is made of a drillable material and is fixedly arranged at the end of the sleeve (1).

2. The drill bit according to claim 1, characterized in that The core (2) comprises a plurality of first blades (4) arranged at intervals along the circumferential direction, and a first flow channel (6) is provided between any two adjacent first blades (4).

3. The drill bit according to claim 2, characterized in that: A plurality of first cutting teeth (7) and first gauge teeth (9) are arranged on the first blade wing (4); the plurality of first cutting teeth (7) and first gauge teeth (9) cover the generatrix of the first blade wing (4); and the number of covering layers of the first cutting teeth (7) and the first gauge teeth (9) on each of the first blade wing (4) is set to 1 to 10 layers.

4. The drillable drill bit according to claim 3, characterized in that The core body (2) is made of aluminum alloy or copper alloy, and the first cutting teeth (7) and the first gauge teeth (9) are arranged on the first blade (4) by cold inserting.

5. The drillable drill bit according to claim 4, characterized in that A mounting hole for mounting the first cutting tooth (7) and the first gauge tooth (9) is provided on the first blade wing (4); the first cutting tooth (7) and the first gauge tooth (9) are fixed in the mounting hole of the first blade wing (4) by interference fit or by a combination of interference fit and adhesive bonding; and a surface of the first blade wing (4) is cold-coated with ceramic glue for strengthening.

6. The drillable drill bit according to any one of claims 1 to 5, characterized in that: The core (2) is connected to the sleeve (1) via a torque transmission mechanism (12).

7. The drillable drill bit according to claim 6, characterized in that The torque transmission mechanism (12) is configured as a thread.

8. The drillable drill bit according to claim 6, characterized in that The torque transmission mechanism (12) comprises a fixing member (16); the core (2) enters the sleeve (1) along the axial direction; the core (2) and the sleeve (1) are fixed by a fixing member (16) arranged radially.

9. The drillable drill bit according to any one of claims 1 to 5, characterized in that: A core hole (13) is coaxially arranged at one end of the core body (2) close to the sleeve (1), and a nozzle (11) is arranged inside the core body (2). Two ends of the nozzle (11) are respectively connected to the core hole (13) and the first flow channel (6), and the central axis of the nozzle (11) is inclined relative to the central axis of the core body (2).

10. The drillable drill bit according to claim 9, characterized in that The sleeve (1) comprises a plurality of second blades (3) distributed in a circumferentially spaced manner, a second flow channel (5) is arranged between two adjacent second blades (3), a plurality of second cutting teeth (8) and second gauge teeth (10) are arranged on the second blade (3), the plurality of second cutting teeth (8) and second gauge teeth (10) are low-temperature silver-welded to the second blade (3) and cover the generatrix of the second blade (3), and tungsten carbide is built-up on the surface of the second blade (3).

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