A self-breaking core drilling bit

Abstract

This invention belongs to the field of geological exploration technology and discloses a self-cutting core drilling bit to solve the problems of long time cycles and low efficiency caused by reinstalling core cutting tools. The invention includes a drill bit body with blades and cutting teeth mounted on them. A core channel is formed in the middle of the drill bit body, and a pressure oil channel is provided on the drill bit body. At least one mounting groove is formed on the inner wall of the core channel, and the cutting teeth are installed in the mounting groove. A first spring is provided between the mounting groove and the cutting teeth. A locking pin hole is formed on the inner wall of the mounting groove, and an elastic locking pin is installed in the cutting teeth. A piston is installed in the pressure oil channel. The piston can slide and compress the elastic locking pin, separating it from the locking pin hole, thereby allowing the cutting teeth to extend into the core channel to cut the core.

Description

Technical Field

[0001] This invention belongs to the field of geological exploration technology, specifically relating to a self-breaking core drilling bit. Background Technology

[0002] Core samples are rock samples extracted during geological exploration by lowering coring tools into a well to the determined stratigraphic level and designed depth. Core samples provide the most direct and practical data for understanding underground oil reservoirs and the characteristics of their fluids. Currently, core samples are primarily obtained using coring drill bits. During drilling, the resulting rock samples typically require specialized coring tools to extract them in chunks.

[0003] Currently, the main method for extracting rock cores from coring drill bits is through the use of specialized coring tools. These tools primarily include an inner core, an outer core, core claws, and a centralizer. The inner core is inserted around the rock core to protect it; the outer core bears the drilling pressure and transmits torque during core drilling, driving the drill bit's rotation and protecting the inner core; the core claws cut the rock core and support the extracted core column.

[0004] Using specialized core-cutting tools to cut rock cores presents the following problems during use:

[0005] The core drill bit stops drilling, and then a core tool is installed inside the core drill bit. Then, the core tool and the core drill bit are rotated together, and the core claw on the core tool is used to cut the core. The whole process takes a long time, resulting in low core extraction efficiency. Summary of the Invention

[0006] To address the problems of long processing times and low efficiency caused by reinstalling coring tools to cut rock cores, this invention provides a self-cutting core drill bit that can cut the rock core after drilling is completed without the need to reinstall existing coring tools, thereby greatly improving the efficiency of core extraction.

[0007] To solve the technical problem, the technical solution adopted by this invention is as follows:

[0008] A self-cutting core drilling bit includes a drill bit body with at least three blades and multiple cutting teeth. A core channel is formed in the middle of the drill bit body. The drill bit body has a pressure oil channel, and the inner wall of the core channel has at least one mounting groove in the radial direction. Cutting teeth for cutting the core are installed in the mounting groove. A first spring is provided between the mounting groove and the cutting teeth to drive the cutting teeth out of the mounting groove. A locking pin hole is provided on the inner wall of the mounting groove, and an elastic locking pin is installed in the cutting teeth to match the locking pin hole. A piston is installed in the pressure oil channel. Under pressure in the pressure oil channel, the piston can slide and compress the elastic locking pin, causing the elastic locking pin to separate from the locking pin hole, thereby allowing the cutting teeth to extend out of the mounting groove and into the core channel to cut the core.

[0009] In some embodiments, the pressure oil passage includes a vertical passage and a horizontal passage. The vertical passage is arranged along the length of the drill bit body. The vertical passage and the horizontal passage are perpendicularly connected to each other. The horizontal passage is arranged parallel to the mounting groove and a piston is installed in the horizontal passage. A second spring is provided between the piston and the end of the horizontal passage.

[0010] In some embodiments, the vertical channel connects to two horizontal channels, which are located on the upper and lower sides of the mounting groove, respectively.

[0011] In some embodiments, the piston has a first channel at the end away from the second spring, and a second channel communicating with the first channel is provided inside the piston. The drill bit body has a through hole for connecting the transverse channel and the mounting groove. When the piston contacts and compresses the elastic locking pin, the second channel is aligned with the through hole and pressurized oil is input into the mounting groove.

[0012] In some embodiments, a limiting block is fixedly installed on the side of the piston facing the second spring, and when the limiting block contacts the bottom of the transverse channel, the second channel of the piston is aligned with the through hole.

[0013] In some embodiments, an annular cavity is provided at one end of the drill bit body away from the cutter blade, and a pressure oil channel is connected to the annular cavity. The annular cavity is equipped with a rotating ring in an annular shape, and a connector is provided on the rotating ring that is connected to the annular cavity. The connector is connected to an external pipeline.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] During the use of the self-cutting core drill bit of the present invention, when the core drill bit is in normal drilling, no pressure oil is supplied to the annular cavity and pressure oil channel. The cutting teeth are held in the mounting groove by the cooperation of the elastic locking pin and the locking pin hole (i.e., the cutting teeth do not extend out of the core), thus preventing the cutting teeth from contacting and damaging the core in the core channel. After the core drill bit has retrieved the core (i.e., the desired core has been obtained from the core channel), pressure oil is supplied to the annular cavity through a pipe. The pressure oil enters the transverse channel through the vertical channel. Overcoming the resistance of the second spring, the pressure oil slides in the transverse channel and squeezes the elastic locking pin in the locking pin hole. The cutting teeth, losing the locking effect of the elastic locking pin, extend out of the mounting groove and enter the core channel under the pushing action of the first spring to contact the core. The core drill bit continues to rotate (without pressing down), causing the cutting teeth to rotate, thereby cutting the core. After cutting, the cutting teeth act as a support for the core, preventing it from falling out of the core channel; finally, it can be pulled out of the drill bit together with the core drill bit.

[0016] In this invention, during the cutting process of the rock core, the pressure oil in the annular cavity, vertical channel and horizontal channel is drawn in reverse through the pipeline. The piston is reset under the action of the second spring, thereby disconnecting the second channel from the through hole. This allows the cutting tooth to maintain a certain strength under the oil pressure of the first spring and the pressure oil.

[0017] During normal drilling, the piston of the core drill bit of the present invention will move away from the second spring under the action of centrifugal force. Therefore, the piston will not contact the elastic locking pin of the cutting tooth under the action of centrifugal force and the force of the second spring. At the same time, the centrifugal force of the first spring and the cutting tooth will also offset part of the elastic force of the first spring. Therefore, the cutting tooth will not extend out of the mounting groove during normal drilling, thereby ensuring the normal drilling of the core drill bit.

[0018] In summary, compared with the existing method of installing coring tools to cut rock cores, the present invention can shorten the coring time and improve the coring efficiency because it does not require reinstalling the coring tools and can complete the self-cutting of the rock core by controlling the cutting teeth. Attached Figure Description

[0019] Figure 1 This is a cross-sectional view of an embodiment of the present invention.

[0020] Figure 2 for Figure 1 A magnified view of a portion of point A in the diagram;

[0021] Figure 3 For this Figure 2 A schematic diagram of the local method at point C;

[0022] Figure 4 for Figure 1 A magnified view of a portion of point B in the diagram;

[0023] The markings in the diagram are: 1. Drill bit body, 2. Cutting blade, 3. Cutting teeth, 4. Core channel, 5. Drilling fluid channel, 6. Vertical channel, 7. Horizontal channel, 8. Mounting groove, 9. Cutting teeth, 10. Elastic locking pin, 11. End cap, 12. First spring, 13. Piston, 131. Second channel, 132. First channel, 14. Second spring, 15. Limiting block, 16. Through hole, 17. Annular cavity, 18. Rotating ring, 19. Connector, 20. Sealing end cap. Detailed Implementation

[0024] The present invention will be further described below with reference to embodiments. These embodiments are merely some, not all, of the embodiments of the present invention. Other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are all within the protection scope of the present invention.

[0025] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. The terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Furthermore, unless otherwise explicitly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention in conjunction with the specific circumstances.

[0026] Combined with appendix Figure 1 To be continued Figure 4The present invention discloses a self-cutting core drilling bit, comprising a drill bit body 1, on which at least three blades 2 are mounted, and multiple cutting teeth 3 are mounted on the blades 2. A core channel 4 is formed in the middle of the drill bit body 1. A drilling fluid channel 5 is also provided on the drill bit body 1, through which drilling fluid is continuously input to cut the cutting teeth 3 and to lift the cutting debris generated during drilling. A pressure oil channel is provided on the drill bit body 1. At least one mounting groove 8 is radially formed on the inner wall of the core channel 4. Cutting teeth 9 for cutting the core are installed in the mounting groove 8. A first spring 12 is provided between the mounting groove 8 and the cutting teeth 9 to drive the cutting teeth 9 out of the mounting groove. One end of the first spring 12 is fixedly connected to the bottom of the mounting groove 8, and the other end is connected to the cutting teeth 9. A locking pin hole is provided on the inner wall of the mounting groove 8, and a useful tool is installed in the cutting teeth 9. The elastic locking pin 10 is adapted to the locking pin hole. The cooperation between the elastic locking pin 10 and the locking pin hole is prior art, which can be understood by those skilled in the art. For example, the elastic locking pin 10 is composed of a locking pin and a spring, which will not be described in detail here. A piston 13 is installed in the pressure oil channel. Under the pressure in the pressure oil channel, the piston 13 can slide and squeeze the elastic locking pin 10, causing the elastic locking pin 10 to separate from the locking pin hole. This allows the cutting teeth 9 to extend out of the mounting groove 8 and into the core channel 4 to cut the core.

[0027] In this invention, the locking pin hole penetrates the mounting groove 8 and the pressure oil passage for mounting the piston 13, thereby allowing the elastic locking pin 10 to extend into the pressure oil passage for mounting the piston 13. When the piston moves, the compression action on the elastic locking pin 10 ensures that the cutting teeth 9 are not affected by the positioning of the elastic locking pin and the locking pin hole.

[0028] In the specific implementation process, the mounting groove 8 is equipped with an end cap 11. After the cutting tooth 9 with the elastic locking pin 10 and the first spring 12 are installed in the mounting groove 8, they are then fixed by the end cap 11. Preferably, the cutting tooth has a small end and a large end. The large end is used to fit against the inner wall of the mounting groove 8 and to position the movement of the cutting tooth 9; the small end is used to pass through the mounting groove 8 to cut the rock core in the core channel 4. Naturally, the end cap 11 also limits the cutting tooth to prevent the cutting tooth 9 from popping out of the mounting groove 8 as a whole. Preferably, the end cap 11 has a through hole in the middle for the small end of the cutting tooth 9 to pass through.

[0029] In some embodiments, the pressure oil channel includes a vertical channel 6 and a horizontal channel 7. The vertical channel 6 is arranged along the length of the drill bit body 1. The vertical channel 1 and the horizontal channel 7 are perpendicularly connected to each other. The horizontal channel 7 is arranged parallel to the mounting groove 8, and the piston 13 is installed in the horizontal channel 13. A second spring 14 is provided between the piston 13 and the end of the horizontal channel 8. The second spring 14 is used to maintain the initial position of the piston 13, prevent the piston from accidentally unlocking the elastic locking pin 10, and ensure the normal drilling of the core drill bit.

[0030] In some embodiments, the vertical channel 6 is connected to two horizontal channels 7, which are located on the upper and lower sides of the mounting groove 8, respectively. That is to say, each horizontal channel 7 is equipped with a piston 13 and a second spring 14. One piston 13 is used to control one elastic locking pin 10. In other words, there is an elastic locking pin 10 in the vertical direction on each of the cutting teeth 9, and each elastic locking pin 10 is triggered by a piston 13.

[0031] In some embodiments, the piston 13 has a first channel 132 at the end opposite to the second spring 14, and a second channel 131 communicating with the first channel 132 is provided inside the piston. The drill bit body 1 has a through hole 16 for connecting the transverse channel 7 and the mounting groove 8. When the piston 13 contacts and compresses the elastic locking pin 10, the second channel 131 is aligned with the through hole 16 and pressurized oil is introduced into the mounting groove 8. By introducing pressurized oil into the mounting groove 8, the cutting teeth 9 can maintain a certain strength when cutting the rock core. When the preload provided by the first spring 12 is insufficient, pressurized oil can be used to supplement it to ensure that the cutting teeth 9 can provide sufficient force to the rock core, thereby ensuring that the cutting teeth 9 can cut the rock core smoothly.

[0032] In some embodiments, a limiting block 15 is fixedly installed on the side of the piston 13 facing the second spring 14. When the limiting block 15 contacts the bottom of the transverse channel 7, the second channel 131 of the piston is aligned with the through hole 16. The limiting block 15 restricts the movement position of the piston 13, thereby ensuring the communication between the through hole 16 and the second channel 131.

[0033] In some embodiments, a through hole 16 can be directly provided between the mounting groove and the transverse channel. The position of the piston and the through hole can be designed so that pressurized oil can be injected into the through hole. For example, when there is no pressurized oil in the transverse channel 7, the piston 13 can block the through hole 16 under the action of the second spring 14. When the piston overcomes the force of the second spring 14 and squeezes the elastic locking pin of the cutting tooth 9 under the action of pressurized oil, the piston 13 can expose the through hole 16, thereby making the transverse channel 7 and the mounting groove 8 interconnected, so as to inject pressurized oil into the mounting groove 8.

[0034] In practice, both piston 13 and cutting tooth 9 are equipped with sealing rings to prevent leakage of pressurized oil.

[0035] In some embodiments, an annular cavity 17 is formed at one end of the drill bit body 1 away from the cutter blade 2. A pressure oil channel communicates with the annular cavity 17. The annular cavity 17 is equipped with a ring-shaped rotating ring 18. A connector 19, which communicates with the annular cavity 17, is formed on the rotating ring 18 and communicates with an external pipeline. Through the structural design of the annular cavity and the rotating ring, the pipeline outside the drill bit body 1 does not need to rotate when the core drill bit is rotating. Preferably, the rotating ring can be formed by splicing two semi-circular structures and finally sealed by a sealing end cap 20. Preferably, the contact surface between the rotating ring 18 and the drill bit body 1, and the contact surface between the rotating ring and / or the connector 19 and the sealing end cap 20, have wear-resistant sealing rings.

[0036] Preferably, a grease hole is also provided between the wear-resistant sealing rings, and grease is injected into the grease hole to reduce the friction during rotation.

[0037] During the use of the self-cutting core drill bit of the present invention, when the core drill bit is in normal drilling, no pressure oil is supplied to the annular cavity and pressure oil channel. The cutting teeth are held in the mounting groove by the cooperation of the elastic locking pin and the locking pin hole (i.e., the cutting teeth do not extend out of the core), thus preventing the cutting teeth from contacting and damaging the core in the core channel. After the core drill bit has retrieved the core (i.e., the desired core has been obtained from the core channel), pressure oil is supplied to the annular cavity through a pipe. The pressure oil enters the transverse channel through the vertical channel. Overcoming the resistance of the second spring, the pressure oil slides in the transverse channel and squeezes the elastic locking pin in the locking pin hole. The cutting teeth, losing the locking effect of the elastic locking pin, extend out of the mounting groove and enter the core channel under the pushing action of the first spring to contact the core. The core drill bit continues to rotate (without pressing down), causing the cutting teeth to rotate, thereby cutting the core. After cutting, the cutting teeth act as a support for the core, preventing it from falling out of the core channel; finally, it can be pulled out of the drill bit together with the core drill bit.

[0038] In this invention, during the cutting process of the rock core, the pressure oil in the annular cavity, vertical channel and horizontal channel is drawn in reverse through the pipeline. The piston is reset under the action of the second spring, thereby disconnecting the second channel from the through hole. This allows the cutting tooth to maintain a certain strength under the oil pressure of the first spring and the pressure oil.

[0039] During normal drilling, the piston of the core drill bit of the present invention will move away from the second spring under the action of centrifugal force. Therefore, the piston will not contact the elastic locking pin of the cutting tooth under the action of centrifugal force and the force of the second spring. At the same time, the centrifugal force of the first spring and the cutting tooth will also offset part of the elastic force of the first spring. Therefore, the cutting tooth will not extend out of the mounting groove during normal drilling, thereby ensuring the normal drilling of the core drill bit.

[0040] In summary, compared with the existing method of installing coring tools to cut rock cores, the present invention can shorten the coring time and improve the coring efficiency because it does not require reinstalling the coring tools and can complete the self-cutting of the rock core by controlling the cutting teeth.

Claims

1. A self-breaking core drilling bit, comprising a drill bit body, wherein at least three cutter wings are mounted on the drill bit body, and multiple cutting teeth are mounted on the cutter wings; a core channel is formed in the middle of the drill bit body, characterized in that, The drill bit body has a pressure oil channel, and the inner wall of the core channel has at least one mounting groove in the radial direction. A cutting tooth for cutting the core is installed in the mounting groove. A first spring is provided between the mounting groove and the cutting tooth to drive the cutting tooth to extend out of the mounting groove. A locking pin hole is provided on the inner wall of the mounting groove. An elastic locking pin is installed in the cutting tooth to match the locking pin hole. A piston is installed in the pressure oil channel. Under the pressure in the pressure oil channel, the piston can slide and squeeze the elastic locking pin to separate the elastic locking pin from the locking pin hole, thereby causing the cutting tooth to extend out of the mounting groove and into the core channel to cut the core. The pressure oil channel includes a vertical channel and a horizontal channel. The vertical channel is arranged along the length of the drill bit body. The vertical channel and the horizontal channel are perpendicularly connected to each other. The horizontal channel is parallel to the mounting groove, and the piston is installed in the horizontal channel. A second spring is provided between the piston and the end of the horizontal channel. A first channel is opened at the end of the piston away from the second spring. A second channel is opened inside the piston and is connected to the first channel. A through hole is opened on the drill bit body to connect the horizontal channel and the mounting groove. When the piston contacts and compresses the elastic locking pin, the second channel is aligned with the through hole and pressure oil is input into the mounting groove. By inputting pressure oil into the mounting groove, the cutting teeth can maintain a certain strength when cutting the rock core.

2. The self-breaking core drilling bit according to claim 1, characterized in that, The vertical channel connects to two horizontal channels, which are located on the upper and lower sides of the mounting groove, respectively.

3. The self-breaking core drilling bit according to claim 1, characterized in that, A limiting block is fixedly installed on the side of the piston facing the second spring. When the limiting block contacts the bottom of the transverse channel, the second channel of the piston is aligned with the through hole.

4. The self-breaking core drilling bit according to claim 1, characterized in that, The drill bit body has an annular cavity at one end away from the cutter blade. The pressure oil channel is connected to the annular cavity. The annular cavity is equipped with a rotating ring in the shape of an annular ring. The rotating ring has a connector that is connected to the annular cavity. The connector is connected to an external pipeline.

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