An impact drill bit for drilling a well

Abstract

The present application relates to the technical field of drilling, and discloses an impact drill bit for drilling, which comprises a drill bit main body, a plurality of wedge-shaped teeth arranged on the central part of the impact rock-breaking surface at the lower end of the drill bit main body, and a plurality of spherical teeth arranged on the circumferential outer edge of the impact rock-breaking surface, wherein each wedge-shaped tooth has the same tooth arrangement density on a concentric circle coaxial with the axis of the drill bit main body, and each spherical tooth has the same tooth arrangement density on a concentric circle coaxial with the axis of the drill bit main body. The central part of the impact rock-breaking surface is provided with wedge-shaped teeth, and the circumferential outer edge of the impact rock-breaking surface is provided with spherical teeth. The wedge-shaped teeth have high rock-breaking efficiency and good wear resistance, and the spherical teeth have high shock resistance and impact resistance. Therefore, the wedge-shaped teeth and the spherical teeth are arranged on the impact rock-breaking surface at the same time, so that the rock-breaking efficiency and wear resistance of the impact drill bit are improved, and the shock resistance and impact resistance of the impact drill bit are also improved.

Description

Technical Field

[0001] This invention relates to the field of drilling technology, and more specifically, to a percussion drill bit for drilling. Background Technology

[0002] In oil and gas drilling, underbalanced drilling media such as air or foam are used as circulating fluids in conjunction with percussion drill bits. Currently, traditional percussion drill bits all use spherical teeth at the bottom rock-breaking section. Although spherical teeth have good impact resistance, the tooth tips are in point contact. As the tooth tips wear, the rock-breaking efficiency of the percussion drill bit gradually decreases and its lifespan is shortened.

[0003] In conclusion, how to avoid the reduction in rock-breaking efficiency of impact drill bits after long-term use is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a percussion drill bit for drilling, wherein the center and outer edge of the percussion rock breaking surface are respectively provided with wedge-shaped teeth and spherical teeth, which effectively improves the rock breaking efficiency, wear resistance, shock resistance and impact resistance of the percussion drill bit.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A percussion drill bit for drilling includes a drill bit body. A plurality of wedge-shaped teeth are provided at the center of the rock-breaking surface at the lower end of the drill bit body, and a plurality of spherical teeth are provided at the outer circumference of the rock-breaking surface. Each of the wedge-shaped teeth has the same tooth density on a concentric circle coaxial with the axis of the drill bit body, and each of the spherical teeth has the same tooth density on a concentric circle coaxial with the axis of the drill bit body.

[0007] Preferably, the outer peripheral surface of the lower end of the drill bit body is provided with a conical toothed surface. The diameter of the conical toothed surface gradually decreases from the end relatively close to the rock-breaking surface to the end relatively far from the rock-breaking surface. The conical toothed surface is uniformly provided with a plurality of inverted serrations along the circumferential direction. The tooth tips of the inverted serrations are set higher than the conical toothed surface.

[0008] Preferably, the tapered insert surface is uniformly provided with at least one ring of the reversed eye teeth along the axial direction, and the reversed eye teeth include cylindrical teeth, PDC teeth, axe-shaped teeth and Mercedes teeth.

[0009] Preferably, the drill bit body has a cylindrical diameter-maintaining surface between the impact rock-breaking surface and the conical toothed surface. The diameter of the cylindrical diameter-maintaining surface is the same as the large end diameter of the conical toothed surface. The cylindrical diameter-maintaining surface has diameter-maintaining teeth, and the tooth tips of the diameter-maintaining teeth are set higher than the cylindrical diameter-maintaining surface.

[0010] Preferably, the drill bit body has a flow channel inside, and the impact rock breaking surface is uniformly provided with a plurality of fluid pulse nozzle assemblies along the circumferential direction, and the fluid pulse nozzle assemblies are connected to the flow channel.

[0011] Preferably, the drill bit body has an external spline in the middle for engaging with the internal spline of the hammer body, and the width of the keyway in the external spline is greater than the width of the internal spline of the hammer body, so as to provide a shock-absorbing strip in the keyway.

[0012] Preferably, the drill bit body has a journal section between the upper impact surface and the middle external spline, and the diameter of the journal section is the same as the minimum outer diameter of the drill bit body.

[0013] Preferably, the drill bit body has a positioning step between the external spline in the middle and the drill teeth at the lower end. The positioning step protrudes from the outer peripheral surface of the drill bit body and is used to cooperate with the hammer body to axially limit the drill bit body.

[0014] Preferably, the upper end of the drill bit body has a plurality of recessed impact grooves on the impact surface, which are used to absorb impact loads and reduce the degree of deformation of the impact surface.

[0015] Preferably, the impact groove includes at least one annular impact groove, which is coaxial with the axis of the drill bit body.

[0016] The percussion drill bit for drilling provided by this invention has wedge-shaped teeth in the center of the rock-breaking surface of the drill bit body and spherical teeth on the outer circumference of the rock-breaking surface. The wedge-shaped teeth have high rock-breaking efficiency and good wear resistance, while the spherical teeth have high vibration and impact resistance. Therefore, the simultaneous arrangement of wedge-shaped teeth and spherical teeth on the rock-breaking surface improves both the rock-breaking efficiency and wear resistance of the percussion drill bit, as well as its vibration and impact resistance. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0018] Figure 1 A schematic diagram of a specific embodiment of the drilling percussion drill bit provided by the present invention;

[0019] Figure 2 for Figure 1 A structural diagram from another direction;

[0020] Figure 3 for Figure 1 Front view diagram;

[0021] Figure 4 for Figure 1 A side view diagram;

[0022] Figure 5 for Figure 1 A side view diagram from another direction.

[0023] Figures 1-5 middle:

[0024] 10-Drill bit body; 1-Impact rock breaking surface; 11-Wedge tooth; 12-Spherical tooth; 2-Gauge protection tooth; 3-Conical insert tooth surface; 31-Reverse reaming tooth; 4-Positioning step; 5-External spline; 6-Junior journal section; 7-Impact surface; 71-Annular impact groove; 8-Flow channel; 9-Fluid pulse nozzle assembly. Detailed Implementation

[0025] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] The core of this invention is to provide a percussion drill bit for drilling, wherein the center and outer edge of the rock-breaking surface are respectively provided with wedge-shaped teeth and spherical teeth, which effectively improves the rock-breaking efficiency, wear resistance, shock resistance and impact resistance of the percussion drill bit.

[0027] The impact drilling bit provided by the present invention includes a drill bit body 10. A plurality of wedge-shaped teeth 11 are provided in the center of the impact rock-breaking surface 1 at the lower end of the drill bit body 10, and a plurality of spherical teeth 12 are provided on the outer circumference of the impact rock-breaking surface 1. Each wedge-shaped tooth 11 has the same tooth density on a concentric circle coaxial with the axis of the drill bit body 10, and each spherical tooth 12 has the same tooth density on a concentric circle coaxial with the axis of the drill bit body 10.

[0028] The drill bit body 10 is used to connect with hammers such as air hammers and foam hammers. In order to transmit torque stably and reliably, the drill bit body 10 is usually connected to the hammer body by a key or even a spline.

[0029] For example, please refer to Figure 3The drill bit body 10 has an external spline 5 in the middle for mating with the spline inside the hammer body. The width of the keyway inside the external spline 5 is greater than the width of the spline inside the hammer body, so that a damping strip can be set in the keyway. The damping strip can be a non-metallic elastic strip. The damping strip is set along the axial direction of the keyway and is used to dampen and buffer when the spline pair transmits torque, so as to eliminate the problem of local stress concentration when the spline pair transmits torque, which is conducive to improving the working environment of the spline pair and increasing the service life of the spline pair.

[0030] The drill bit body 10 has a flow channel 8 inside and a drilling fluid outlet at the impact rock breaking surface 1 at the lower end, so that the drilling fluid can flow out to clean the bottom of the well and carry away rock cuttings, thereby keeping the bottom of the well clean, avoiding repeated cutting by the drill teeth, reducing wear of the drill teeth and improving cutting efficiency.

[0031] For preferred options, please refer to [the provided text]. Figure 1 and Figure 2 The drill bit body 10 has a flow channel 8 inside. The flow channel 8 is usually arranged along the axial direction of the drill bit body 10. At the lower end of the rock breaking surface 1, a number of fluid pulse nozzle assemblies 9 are evenly arranged along the circumferential direction. The fluid pulse nozzle assemblies 9 are connected to the flow channel 8. The specific number, structure, size and distribution of the flow channel 8 and the fluid pulse nozzle assemblies 9 are determined according to the actual production needs and with reference to the existing technology.

[0032] After the circulating fluid flows into the fluid pulse nozzle assembly 9 at high speed through the flow channel 8, fluid pulse waves are generated in the cavitation excitation chamber of the fluid pulse nozzle assembly 9, and finally ejected to form pulse fluid. Compared with ordinary high-speed fluid, it is more conducive to cleaning the sand carried at the bottom of the well and can reduce the problem of secondary wear of drill teeth and improve the service life of drill teeth.

[0033] The lower end face of the drill bit body 10 is the rock-breaking surface 1. Several wedge-shaped teeth 11 are provided in the center of the rock-breaking surface 1. The tooth tip of the wedge-shaped teeth 11 is in line contact with the rock. Compared with the point contact between the tooth tip of the spherical teeth 12 and the rock, the wedge-shaped teeth 11 have stronger wear resistance. Moreover, the rock-breaking efficiency of the narrow impact surface is significantly higher than that of the circular impact surface formed after the spherical teeth 12 wears out, thus ensuring the rock-breaking efficiency and wear resistance of the impact drill bit.

[0034] Meanwhile, the outer edge of the rock-breaking surface 1 is provided with several spherical teeth 12. The spherical teeth 12 have an axisymmetric structure. During the rock-breaking process, the spherical teeth 12 are subjected to similar stress states in all directions, which makes it less likely for the wedge-shaped teeth 11 to break, thus ensuring the shock resistance and impact resistance of the impact drill bit.

[0035] In order to ensure that the force on the wedge teeth 11 in all directions of the impact rock breaking surface 1 is relatively uniform and that the impact rock breaking amount of each wedge tooth 11 is the same, each wedge tooth 11 is set to have the same tooth density on a concentric circle set coaxial with the axis of the drill bit body 10, so as to prevent a certain wedge tooth 11 from wearing out too early and affecting the overall rock breaking efficiency of the impact drill bit.

[0036] In order to ensure that the force on the spherical teeth 12 in all directions of the impact rock breaking surface 1 is relatively uniform and that the impact rock breaking amount of each spherical tooth 12 is the same, each spherical tooth 12 is set to have the same tooth density on a concentric circle set coaxial with the axis of the drill bit body 10, so as to prevent the premature wear of a certain spherical tooth 12 from affecting the overall rock breaking efficiency of the impact drill bit.

[0037] The specific structure, shape, distribution, and tooth density of the wedge teeth 11 and the spherical teeth 12 are determined based on factors such as the design rock-breaking efficiency and design service life of the impact drill bit in actual production. For example, the tooth density of the wedge teeth 11 is usually set to be slightly greater than that of the spherical teeth 12 in order to improve the overall rock-breaking efficiency of the impact drill bit.

[0038] To further improve rock breaking efficiency, it is preferable to set the central area of ​​the impact rock breaking surface 1 as a conical surface. Therefore, during the drilling process, the rock being drilled will have a matching conical surface. The matching of the conical surface of the impact rock breaking surface 1 with the conical surface of the rock can effectively improve the centering of the drill bit during drilling, reduce the radial vibration of the drill bit and each drill tooth, and thus improve the service life of the drill teeth.

[0039] In this embodiment, the rock-breaking surface 1 of the drill bit body 10 is provided with a wedge-shaped tooth 11 in the center and a spherical tooth 12 on the outer edge of the rock-breaking surface 1. The wedge-shaped tooth 11 has high rock-breaking efficiency and good wear resistance, while the spherical tooth 12 has high vibration and impact resistance. Therefore, the simultaneous arrangement of wedge-shaped teeth 11 and spherical teeth 12 on the rock-breaking surface 1 improves both the rock-breaking efficiency and wear resistance of the impact drill bit and its vibration and impact resistance.

[0040] Based on the above embodiment, the outer peripheral surface of the lower end of the drill bit body 10 is provided with a conical toothed surface 3. The diameter of the conical toothed surface 3 gradually decreases from the end that is relatively close to the rock breaking surface 1 to the end that is relatively far away from the rock breaking surface 1. The conical toothed surface 3 is uniformly provided with a number of inverted serrations 31 along the circumferential direction. The tooth tip of the inverted serrations 31 is set higher than the conical toothed surface 3.

[0041] In order to better scrape the narrow-diameter formation and crushed blocks and improve scraping efficiency, a tapered toothed surface 3 is usually provided with at least one ring of reverse-scraping teeth 31 evenly arranged in the axial direction. That is, the axis of the tooth tip circle formed by connecting the tooth tips of the ring of reverse-scraping teeth 31 is collinear with the axis of the drill bit body 10.

[0042] The tooth shape of the inverted eye tooth 31 is not limited. It can be set as a regular cylindrical tooth that is easy to process, or it can be set as a special tooth such as PDC tooth, axe tooth, and Mercedes tooth. The specific tooth shape can be determined according to the geological conditions of the formation during drilling, etc., which will not be elaborated here.

[0043] When the percussion drill bit encounters a narrowing of the upper formation and causes a block to fall, resulting in stuck drill bit, the tapered insert tooth surface 3 gradually decreases in size along the drilling direction. Therefore, the diameter of the tooth tip circle formed by the connection of the tooth tips of the relatively forward inverted slashing teeth 31 is smaller than the diameter of the tooth tip circle formed by the connection of the tooth tips of the relatively rearward inverted slashing teeth 31. This allows the inverted slashing teeth 31 to scrape the formation and the broken block at the narrowing of the diameter until the block is completely broken by the inverted slashing teeth 31 and the formation at the narrowing of the diameter is scraped to the normal wellbore size, thus enabling the normal lifting operation of the drill string.

[0044] When the impact drill bit rotates downhole, the rock inevitably has uneven fragmentation and incomplete fragmentation around the circumference of the impact rock breaking surface 1. The incompletely fragmented rock will affect the wellbore diameter.

[0045] To this end, a cylindrical diameter-maintaining surface can be provided between the impact rock-breaking surface 1 and the conical toothed surface 3 of the drill bit body 10. The diameter of the cylindrical diameter-maintaining surface is the same as the large end diameter of the conical toothed surface 3. The cylindrical diameter-maintaining surface is provided with diameter-maintaining teeth 2. The tooth tip of the diameter-maintaining teeth 2 is set higher than the cylindrical diameter-maintaining surface. Therefore, the diameter-maintaining teeth 2 can scrape and break the rock that is not completely broken, thereby meeting the circumferential size requirements of the wellbore.

[0046] The diameter-maintaining teeth 2 are usually set as columnar teeth. The specific number, structure, size and distribution of the diameter-maintaining teeth 2 are determined according to the needs of actual production, and will not be elaborated here.

[0047] Considering that impact drill bits have a certain risk of breakage during drilling operations, based on the above embodiment, in order to avoid random breakage of the drill bit body 10 and difficulty in retrieval, the drill bit body 10 can be provided with a journal section 6 between the upper impact surface 7 and the middle external spline 5. The diameter of the journal section 6 is the same as the minimum outer diameter of the drill bit body 10.

[0048] Since the diameter of the drill bit body 10 is smallest at the journal section 6, the journal section 6 is the structural weak point of the drill bit body 10. When the impact load on the impact drill bit 10 is too large, the drill bit body 10 will break at the journal section 6. Since the fracture location of the drill bit body 10 is fixed, the difficulty of salvage is effectively reduced.

[0049] Based on the above embodiments, the drill bit body 10 may be provided with a positioning step 4 between the outer spline 5 in the middle and the drill tooth part at the lower end. The positioning step 4 protrudes from the outer peripheral surface of the drill bit body 10 and is used to cooperate with the hammer body to axially limit the drill bit body 10.

[0050] When the drill bit body 10 breaks at the journal section 6, the lower middle part of the drill bit body 10 falls downward until the positioning step 4 contacts the mating part of the hammer body. Thus, the positioning step 4 is used to axially limit the lower middle part of the broken drill bit body 10, preventing the broken drill bit body 10 from falling completely and significantly reducing the difficulty of salvage.

[0051] The upper surface of the drill bit body 10 is the impact surface 7, which needs to withstand the downward impact of the moving piston of the hammer. In order to prevent the impact from causing the impact surface 7 to be upset and causing the drill bit body 10 to jam with the mating parts, preferably, the impact surface 7 at the upper end of the drill bit body 10 can be provided with a number of recessed impact grooves. The impact grooves are used to absorb the impact load and reduce the degree of deformation of the impact surface 7.

[0052] When the hammer impacts the impact surface 7 of the drill bit body 10, the impact surface 7 can bend and deform towards the recessed impact groove, thereby absorbing part of the impact load, reducing the upsetting deformation of the impact surface 7, and thus avoiding the problem of the drill bit body 10 and the mating parts getting stuck.

[0053] The impact-bearing groove can be at least one annular impact-bearing groove 71, which is coaxial with the axis of the drill bit body 10, such as... Figure 5 As shown;

[0054] The impact groove can also be a number of impact recesses. The impact recesses are evenly distributed along the circumference of the impact surface 7 and evenly distributed along the radial direction of the impact surface 7.

[0055] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0056] The drilling percussion drill bit provided by the present invention has been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of the invention. The descriptions of the embodiments above are only for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principles of the invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A percussion drill bit for drilling, characterized in that, The drill bit body (10) includes a drill bit body (10). The center of the rock-breaking surface (1) at the lower end of the drill bit body (10) is provided with a number of wedge-shaped teeth (11). The outer edge of the rock-breaking surface (1) is provided with a number of spherical teeth (12). Each wedge-shaped tooth (11) has the same tooth density on a concentric circle coaxial with the axis of the drill bit body (10). Each spherical tooth (12) has the same tooth density on a concentric circle coaxial with the axis of the drill bit body (10).

2. The drilling percussion bit according to claim 1, characterized in that, The outer circumferential surface of the lower end of the drill bit body (10) is provided with a conical toothed surface (3). The diameter of the conical toothed surface (3) gradually decreases from the end that is relatively close to the impact rock breaking surface (1) to the end that is relatively far away from the impact rock breaking surface (1). The conical toothed surface (3) is uniformly provided with a number of inverted eye teeth (31) along the circumferential direction. The tooth tip of the inverted eye teeth (31) is set higher than the conical toothed surface (3).

3. The drilling percussion bit according to claim 2, characterized in that, The conical toothed surface (3) is uniformly provided with at least one ring of the inverted eye teeth (31) along the axial direction. The inverted eye teeth (31) include cylindrical teeth, PDC teeth, axe-shaped teeth and Mercedes teeth.

4. The drilling percussion bit according to claim 2, characterized in that, The drill bit body (10) has a cylindrical diameter protection surface between the impact rock breaking surface (1) and the conical toothed surface (3). The diameter of the cylindrical diameter protection surface is the same as the large end diameter of the conical toothed surface (3). The cylindrical diameter protection surface is provided with diameter protection teeth (2), and the tooth tip of the diameter protection teeth (2) is set higher than the cylindrical diameter protection surface.

5. The drilling percussion drill bit according to any one of claims 1-4, characterized in that, The drill bit body (10) has a flow channel (8) inside, and the impact rock breaking surface is uniformly provided with a number of fluid pulse nozzle assemblies (9) along the circumferential direction. The fluid pulse nozzle assemblies (9) are connected to the flow channel (8).

6. The drilling percussion bit according to any one of claims 1-4, characterized in that, The drill bit body (10) is provided with an external spline (5) in the middle for cooperating with the internal spline of the hammer body. The width of the keyway in the external spline (5) is greater than the width of the internal spline of the hammer body, so as to set a shock-absorbing strip in the keyway.

7. The drilling percussion bit according to claim 6, characterized in that, The drill bit body (10) has a journal section (6) between the upper impact surface (7) and the middle external spline (5), and the diameter of the journal section (6) is the same as the minimum outer diameter of the drill bit body (10).

8. The drilling percussion bit according to claim 7, characterized in that, The drill bit body (10) has a positioning step (4) between the external spline (5) in the middle and the drill tooth part at the lower end. The positioning step (4) protrudes from the outer peripheral surface of the drill bit body (10) and is used to cooperate with the hammer body to axially limit the drill bit body (10).

9. The drilling percussion bit according to any one of claims 1-4, characterized in that, The upper end of the drill bit body (10) has a plurality of recessed impact grooves on the impact surface (7), which are used to absorb impact loads and reduce the degree of deformation of the impact surface (7).

10. The drilling percussion bit according to claim 9, characterized in that, The impact groove includes at least one annular impact groove (71), which is coaxial with the axis of the drill bit body (10).

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