Drill bits for breaking rock

Abstract

The present invention relates to a drill bit for crushing rocks, comprising: a drilling sleeve, the drilling sleeve extending in the axial direction, the drilling sleeve being configured with a plurality of sleeve drilling teeth for crushing rocks, the drilling sleeve being configured with a hollow space for accommodating a rock column; and a plurality of inner crushing teeth, the plurality of inner crushing teeth being spaced apart from the end face of the working end of the drilling sleeve in the axial direction, the plurality of inner crushing teeth being located in the hollow space of the drilling sleeve; wherein, during drilling, the formation opposite to the hollow space of the drilling sleeve will not be crushed by the sleeve drilling teeth of the drilling sleeve, so that the rock column can be accommodated in the hollow space, the rock column cooperates with the drilling sleeve to limit the lateral position of the drill bit, and when the rock column extends to the plurality of inner crushing teeth, the plurality of inner crushing teeth crush the rock column. Vibration reduction can be effectively achieved by this drill bit.

Description

Technical Field

[0001] The invention relates to the technical field of oil drilling, in particular to a drill bit for breaking rocks. Background Art

[0002] The drill bit is the main tool for breaking rocks. The quality of the drill bit, whether the drill bit is suitable for the lithology (for example, hardness) and other drilling process conditions will directly affect the drilling speed, drilling quality and drilling cost. For example, if the formation hardness is too large relative to the drill bit, it will cause very obvious lateral vibration and axial vibration, leading to serious drill jumping. There are still many problems in the current drilling operation, and the research on drill bits is still in the development stage.

[0003] Existing drill bits often have a plurality of claws surrounding the main body, each of which is provided with corresponding crushing teeth for crushing the contacted formation rock. However, for formations with very high hardness, these existing drill bits will produce very large vibrations.

[0004] CN107762417A discloses a vibration-proof and damage-proof PDC drill bit with a drilling equipment protection function. The drill bit is vibration-proof by providing movable parts such as a piston and a return spring. However, these movable parts are easily damaged during use and have poor reliability.

[0005] CN109538128A discloses a vibration-proof PDC drill bit. The drill bit improves the stability of the drill bit by making each cutting tooth have its own unique placement angle, thereby improving the vibration reduction function of the drill bit. However, this configuration structure has very limited adaptability to complex conditions underground, and cannot continuously and effectively achieve the vibration reduction function in actual operations.

[0006] Therefore, there is a need for a drill bit for breaking rocks that can effectively reduce vibration. Summary of the invention

[0007] In view of the above problems, the present invention provides a drill bit for breaking rocks. Vibration reduction can be effectively achieved by using the drill bit.

[0008] According to the present invention, a drill bit for crushing rocks is proposed, comprising: a drilling sleeve, the drilling sleeve extending axially, the drilling sleeve being configured with a plurality of sleeve drilling teeth for crushing rocks, the drilling sleeve being configured with a hollow space for accommodating a rock column; and a plurality of inner crushing teeth, the plurality of inner crushing teeth being axially spaced apart from the end face of the working end of the drilling sleeve, the plurality of inner crushing teeth being located in the hollow space of the drilling sleeve; wherein, during drilling, the stratum opposite to the hollow space of the drilling sleeve will not be crushed by the sleeve drilling teeth of the drilling sleeve, so that the rock column can be accommodated in the hollow space, the rock column cooperates with the drilling sleeve to limit the lateral position of the drill bit, and when the rock column extends to the plurality of inner crushing teeth, the plurality of inner crushing teeth crush the rock column.

[0009] During the drilling process of the drill bit, the drilling sleeve first drills into the formation so that a rock column can be maintained in the hollow space. The cooperation between the rock column and the drilling sleeve can limit the lateral position of the drill bit, thereby weakening or even avoiding the lateral vibration of the drill bit. By avoiding lateral vibration, the efficiency and speed of drilling can be effectively improved. At the same time, the structural stability of the drill bit can be improved and the service life can be extended. This can effectively reduce the cost of drilling.

[0010] In one embodiment, the drill bit also includes an axially extending drill bit body, and an injection hole for distributing drilling fluid is constructed on the end face of the working end of the drill bit body. The drilling sleeve extends axially from the working end of the drill bit body, and the injection hole is connected to the hollow space, wherein a plurality of radially penetrating grooves are constructed at the working end of the drilling sleeve, and the drilling fluid injected into the hollow space by the injection hole can flow to the annulus outside the drill bit through the grooves.

[0011] In one embodiment, the groove includes a threading surface oriented toward a rotation direction of the drill bit, and the plurality of sleeve drilling teeth include a first sleeve drilling tooth protruding from the threading surface of the groove.

[0012] In one embodiment, the cutting portion of the first sleeve drilling tooth at least partially extends beyond the end surface of the working end of the drilling sleeve in the axial direction.

[0013] In one embodiment, a flow channel extending axially and communicating with the groove is constructed on the inner side surface of the drilling sleeve, and the drilling fluid entering the hollow space through the injection hole can flow to the groove through the flow channel.

[0014] In one embodiment, the inner end of the groove has a smaller cross-section than the outer end, so that the groove has a radial shape.

[0015] In one embodiment, the plurality of sleeve drilling teeth include a second sleeve drilling tooth protruding from an end surface of the working end of the drilling sleeve.

[0016] In one embodiment, the axial distance between the end face of the working end of the drilling sleeve and the inner crushing teeth is sufficient to enable the friction between the rock column in the hollow space and the inner side surface of the drilling sleeve to avoid axial vibration and torsional vibration of the drill bit.

[0017] In one embodiment, the drill bit also includes: an axially extending drill bit body; and a plurality of inner crushing ridges, wherein the plurality of inner crushing ridges are circumferentially spaced from each other on the end face of the working end of the drill bit body, and the plurality of inner crushing teeth are arranged on each inner crushing ridge.

[0018] In one embodiment, the drill bit also includes: an axially extending drill bit body; and a plurality of outer crushing ridges, wherein the plurality of outer crushing ridges are circumferentially spaced from each other on the outer circumferential surfaces of the drill bit body and the drilling sleeve, each outer crushing ridge extends axially, and a plurality of outer crushing teeth are arranged on each outer crushing ridge.

[0019] The drill bit of the present invention provides an idea of ​​breaking the formation in stages, that is, first destroying a part of the formation rock in an annular shape to form a rock column, and then breaking the rock column. In the present invention, the cooperation between the rock column and the drilling sleeve can at least weaken the lateral vibration, and in some cases can even weaken the axial vibration and / or torsional vibration. By weakening these vibrations, the occurrence of drill jumping can be avoided, effectively improving the drilling efficiency and reducing the drilling cost. The drill bit of this structure has strong adaptability and can be generally applied to a large number of formation conditions without the need for high customization. In addition, this drill bit has no moving parts, has strong structural stability, is not easy to damage, and has high reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The present invention will be described in more detail below with reference to the accompanying drawings, wherein:

[0021] Figure 1 shows a schematic diagram of a drill bit for breaking rock according to one embodiment of the present invention;

[0022] Figure 2 Shows Figure 1 A schematic side view of a drill bit in FIG.

[0023] Figure 3 Shows Figure 1 Schematic diagram of the top view of the drill bit.

[0024] In the drawings, the same reference numerals are used for the same components. The drawings are not drawn to scale. DETAILED DESCRIPTION

[0025] The present invention will be further described below in conjunction with the accompanying drawings.

[0026] Figures 1 to 3 An embodiment of a drill bit 100 for breaking rock according to the invention is schematically shown.

[0027] The drill bit 100 includes a generally cylindrical drill bit body 120. A connecting thread section (male thread) 110 is provided at the connecting end of the drill bit body 120 for connecting with other parts of the drilling tool. A drilling sleeve 130 is connected to the working end of the drill bit body 120. The drilling sleeve 130 has a generally cylindrical shape and extends axially from the working end of the drill bit body 120.

[0028] like Figure 1 As shown, the outer side surface of the drilling sleeve 130 can be aligned with the outer surface of the drill bit body 120. A cylindrical hollow space is formed inside the drilling sleeve 130. An injection hole (e.g., a nozzle) 121 is provided on the end surface of the working end of the drill bit body 120. The injection hole 121 is located in the above-mentioned hollow space to communicate with the hollow space. When the drill bit 100 is working, drilling fluid (e.g., water) can be injected into the hollow space through the injection hole 121. The functions of the drilling fluid include: (1) cooling the part being drilled; (2) providing lubrication for the part of the drill bit that contacts the rock; and (3) taking the broken rock debris away from the hollow space and the formation being drilled.

[0029] It should be understood that the injection holes may also have other arrangements, as long as they can communicate with the hollow space so as to be able to inject drilling fluid into the hollow space.

[0030] In order to facilitate the drilling fluid to flow out of the hollow space, flow to the annulus between the drill bit and the formation, and then flow to the ground, a plurality of grooves 131 may be constructed at the working end of the drilling sleeve 130. These grooves 131 may penetrate the side wall of the drilling sleeve 130 in the radial direction, so as to achieve the communication between the hollow space and the annulus. Figure 1 and Figure 3 As shown, the end (inner end) of the groove 131 close to the hollow space has a smaller cross section, while the end (outer end) of the groove 131 away from the hollow space has a larger cross section, so that the groove has a radial shape. Through this structure, the fluid carrying the cuttings can quickly flow out of the drilling sleeve 130, thereby preventing the retention and accumulation of the cuttings.

[0031] In one embodiment, a plurality of circulation channels (not shown) may be provided on the inner side of the drilling sleeve 130. Each circulation channel extends in the axial direction and communicates with a corresponding groove 131. This facilitates the drilling fluid to carry rock debris out of the hollow space.

[0032] In addition, a sleeve drilling tooth, preferably a plurality of sleeve drilling teeth, is provided at the working end of the drilling sleeve 130. For example, the plurality of sleeve drilling teeth may include a plurality of first sleeve drilling teeth 132. Figure 1 As shown, the first sleeve drilling teeth 132 are arranged on the screw-in surface of the groove 131 and protrude relative to the screw-in surface, thereby being able to cut the formation rock when the drill bit rotates. The screw-in surface here refers to the direction of rotation R of the groove 131 (see Figure 3 ) oriented side.

[0033] In a preferred embodiment, the cutting portion of the first sleeve drilling tooth 132 at least partially extends axially beyond the end surface 133 of the working end of the drilling sleeve 130. This is conducive to the first sleeve drilling tooth 132 to break the formation rock.

[0034] As an alternative or in addition, the plurality of sleeve drilling teeth may further include a plurality of second sleeve drilling teeth (not shown) protruding relative to the end surface 133 of the working end of the drilling sleeve 130. The plurality of second sleeve drilling teeth are spaced apart from each other. The second sleeve drilling teeth may also effectively break the formation rock.

[0035] It should be understood that, in the case where the second sleeve drilling teeth are provided, the drilling fluid and rock debris can be discharged through the gaps between the second sleeve drilling teeth spaced apart from each other. Therefore, the groove 131 and the first sleeve drilling teeth 132 can be omitted.

[0036] In addition, the drill bit 100 may further include a plurality of inner crushing ridges 150 disposed on the end surface of the working end of the drill bit body 120. The inner crushing ridges 150 are spaced apart from each other in the circumferential direction and are arranged substantially radially. A plurality of inner crushing teeth 151 are disposed on each inner crushing ridge 150. The inner crushing teeth 151 are disposed on the screw-in end (i.e., the end oriented toward the rotation direction R) of the inner crushing ridge 150. The inner crushing teeth 151 are used to crush the rock in the hollow space.

[0037] As required, the inner crushing teeth 151 and the inner crushing ridges 150 may also be provided with other forms or structures.

[0038] In addition, the drill bit 100 may further include a plurality of outer crushing ridges 140 disposed on the outer side of the drill bit body 120. Each outer crushing ridge 140 extends in the axial direction. The plurality of outer crushing ridges 140 are spaced apart from each other in the circumferential direction. Figure 3 As shown, each outer crushing ridge 140 can also extend to the outer side of the drilling sleeve 130 and extend to the vicinity of the working end face of the drilling sleeve 130. A plurality of outer crushing teeth are arranged on each outer crushing ridge 140. These outer crushing teeth include a plurality of first outer crushing teeth 141. These first outer crushing teeth 141 are arranged on the screw-in end of the outer crushing ridge 140. These outer crushing teeth can also include a plurality of second outer crushing teeth 142. These second outer crushing teeth 142 are arranged on the outer side of each outer crushing ridge 140. The formation outside the drilling sleeve 130 can be drilled by the first outer crushing teeth 141 and the second outer crushing teeth 142 on the outer crushing ridge 140 to ensure that the wellbore has a sufficient and appropriate size. At the same time, the arrangement of the outer crushing ridge 140 can also prevent the drill bit body 120 and the outer side of the drilling sleeve 130 from directly contacting the formation. This is conducive to reducing the resistance when the drill bit is working. In addition, channels for fluid carrying rock debris to flow to the ground may be formed between adjacent outer crushing ridges 140 .

[0039] As required, the outer crushing teeth and the outer crushing ridges 140 may also be provided with other forms or structures.

[0040] During the operation of the drill bit 100 of the present invention, the working end (or the sleeve drilling teeth) of the drilling sleeve 130 first contacts the stratum. As the drill bit 100 rotates, the drilling sleeve 130 performs annular drilling on the stratum. As a result, the stratum opposite to the hollow space of the drilling sleeve 130 will not be broken by the drilling sleeve 130, but will extend into the hollow space to form a rock column as the drill bit 100 drills. The cooperation between the rock column and the drilling sleeve 130 can limit the lateral position of the drilling sleeve 130 and even the entire drill bit 100, thereby facilitating the reduction of the lateral vibration of the drill bit 100.

[0041] The length of the rock column is limited by the distance h between the end surface 133 of the working end of the drilling sleeve 130 and the inner crushing teeth 151. When the top of the rock column extends to the inner crushing teeth 151, as the drill bit 100 rotates, the inner crushing teeth 151 crush the top of the rock column.

[0042] Thus, a staged formation rock crushing process is formed. Through this process, vibration reduction can be effectively achieved while ensuring that the drill bit 100 can effectively crush the formation rock.

[0043] In addition, the distance h can be long enough to effectively reduce the axial vibration and torsional vibration of the drill bit 100 through the friction between the inner side of the drilling sleeve 130 and the outer side of the rock column. For situations where an inclined well or a horizontal well or other situations where the drilling direction needs to be changed, the distance h needs to be relatively limited to ensure that the drilling direction can be flexibly changed.

[0044] The drill bit 100 of the present invention is particularly suitable for drilling in formations with relatively high hardness. Even in this case, no large vibration (especially lateral vibration) is generated, thereby improving the efficiency and speed of drilling and improving the safety of drilling.

[0045] In this document, unless otherwise clearly defined or there is a contradiction, directional terms such as “axial”, “radial” and “circumferential” are used to describe the entire drill bit, or to describe the drill bit body 120 and the drilling sleeve 130 as main components.

[0046] Although the present invention has been described with reference to preferred embodiments, various modifications may be made thereto and parts thereof may be replaced by equivalents without departing from the scope of the present invention. In particular, the various technical features mentioned in the various embodiments may be combined in any manner as long as there are no structural conflicts. The present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A drill bit for breaking rocks, comprising: A drill bit body extending in the axial direction, an injection hole for distributing drilling fluid is configured on the end face of the working end of the drill bit body, a drilling sleeve, the drilling sleeve is cylindrical, extends axially from the working end of the drill bit body, the drilling sleeve is configured to accommodate a hollow space in a rock column, the injection hole is connected to the hollow space, a plurality of radially penetrating grooves are configured at the working end of the drilling sleeve, the drilling fluid injected into the hollow space by the injection hole can flow to the annulus outside the drill bit through the grooves, the groove includes a screw-in surface oriented toward the rotation direction of the drill bit, the drilling sleeve is configured with a plurality of sleeve drilling teeth for crushing rocks, the plurality of sleeve drilling teeth include a first sleeve drilling tooth protruding from the screw-in surface of the groove; and A plurality of inner crushing teeth, the plurality of inner crushing teeth are axially spaced apart from an end surface of a working end of the drilling sleeve, and the plurality of inner crushing teeth are located in a hollow space of the drilling sleeve; During drilling, the stratum opposite to the hollow space of the drilling sleeve will not be crushed by the sleeve drilling teeth of the drilling sleeve, so that the rock column can be accommodated in the hollow space. The rock column cooperates with the drilling sleeve to limit the lateral position of the drill bit. When the rock column extends to the multiple inner crushing teeth, the multiple inner crushing teeth crush the rock column.

2. The drill bit for breaking rocks according to claim 1, characterized in that: The cutting portion of the first sleeve drilling tooth at least partially extends beyond the end surface of the working end of the drilling sleeve in the axial direction.

3. The drill bit for breaking rocks according to claim 2, characterized in that: A flow channel extending in the axial direction and communicating with the groove is constructed on the inner side surface of the drilling sleeve, and the drilling fluid entering the hollow space from the injection hole can flow to the groove through the flow channel.

4. The drill bit for breaking rocks according to claim 2, characterized in that: The inner end of the groove has a smaller cross-section than the outer end, so that the groove has a radial shape.

5. The drill bit for breaking rocks according to claim 1, characterized in that: The plurality of sleeve drilling teeth include a second sleeve drilling tooth protruding from an end surface of the working end of the drilling sleeve.

6. The drill bit for breaking rocks according to claim 1, characterized in that: The axial distance between the end face of the working end of the drilling sleeve and the inner crushing teeth is sufficient to ensure that the friction between the rock column in the hollow space and the inner side surface of the drilling sleeve can avoid axial vibration and torsional vibration of the drill bit.

7. The drill bit for breaking rocks according to any one of claims 1 to 6, characterized in that: The drill bit also includes: an axially extending drill bit body; and A plurality of inner crushing ridges are spaced apart from each other in the circumferential direction on the end surface of the working end of the drill bit body, and a plurality of inner crushing teeth are arranged on each inner crushing ridge.

8. The drill bit for breaking rocks according to any one of claims 1 to 6, characterized in that: The drill bit also includes: an axially extending drill bit body; and A plurality of outer crushing ridges are spaced apart from each other in the circumferential direction on the outer circumferential surfaces of the drill bit body and the drilling sleeve, each outer crushing ridge extends in the axial direction, and a plurality of outer crushing teeth are arranged on each outer crushing ridge.

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