A coring bit for rapid drilling

Abstract

The present invention belongs to the technical field of geological exploration and discloses a coring bit for rapid drilling. In order to solve the problems of difficult chip removal caused by soil adhesion and reduced cutting progress of cutting teeth when the coring bit drills in soft formations and clay formations. The present invention includes a bit body. The lower end of the bit body has a plurality of cutter wings, and a plurality of cutting teeth are installed on each cutter wing. A coring channel is formed in the middle of the bit body. A main drilling fluid channel is opened on the bit body. The main drilling fluid channel communicates with a first channel and a second channel. The outlet of the first channel faces the direction of the main cutting teeth on the cutter wing. The outlet of the second channel is located at the upper part of the cutter wing, and the outlet of the second channel is opened obliquely downward at the upper part of the cutter wing, and the outlet direction of the second channel is opposite to the rotation direction of the bit body.

Description

Technical Field

[0001] The present invention belongs to the technical field of geological exploration, and particularly relates to a core bit for rapid drilling. Background Art

[0002] A core is a rock sample drilled out by lowering a core-taking tool into a well according to the stratigraphic horizons obtained from the exploration and the designed depth during geological exploration. The core is the most intuitive and practical data for understanding the underground oil layer and the characteristics of the contained fluids. At present, for obtaining cores, basically a core bit is used for drilling, and the cores generated during the drilling process of the core bit generally need to be taken out in blocks by using a special core-taking tool.

[0003] Currently, the drilling fluid channels of core bits generally face the main cutting teeth on the blade (i.e., the lowermost cutting teeth on the blade) to facilitate the impact and cooling of the cutting teeth. However, when the core bit drills in soft formations and clay formations, there is a serious problem of soil adhesion around the cutting teeth. On the one hand, the soil adhesion hinders the discharge of debris. Difficult discharge of debris will lead to debris accumulation, which will aggravate the adhesion of the debris to the cutting teeth under the rotational impact of the core bit, thereby reducing the cutting progress of the cutting teeth. Summary of the Invention

[0004] In order to solve the problems of difficult chip removal caused by soil adhesion and reduced cutting progress of cutting teeth when the core bit drills in soft formations and clay formations, the present invention provides a core bit for rapid drilling, which can adjust the ejection direction of the drilling fluid, so that the drilling fluid can not only wash and cool the cutting teeth, but also impact and break the debris to form smaller debris, thereby facilitating the discharge of debris and achieving the purpose of improving the drilling efficiency.

[0005] In order to solve the technical problems, the technical solution adopted by the present invention is:

[0006] A core bit for rapid drilling, including a bit body. The lower end of the bit body has a plurality of blades, and a plurality of cutting teeth are installed on each blade. A core-taking channel is formed in the middle of the bit body. The bit body is provided with a main drilling fluid channel, and the main drilling fluid channel is communicated with a first channel and a second channel. The outlet of the first channel faces the direction of the main cutting teeth on the blade, the outlet of the second channel is located at the upper part of the blade, and the outlet of the second channel is obliquely downwardly opened at the upper part of the blade, and the outlet direction of the second channel is opposite to the rotation direction of the bit body.

[0007] In some embodiments, a control structure for controlling the on-off of the second channel is arranged on the second channel.

[0008] In some embodiments, the control structure includes a liquid inlet channel and an installation cavity formed in the drill bit body. A piston body is disposed in the installation cavity. There is a through hole between the installation cavity and the second channel. The upper end of the piston body is located in the installation cavity and is in sealing cooperation with the inner wall of the installation cavity. The lower end of the piston body can pass through the through hole and extend into the second channel. A spring is disposed between the top of the piston body and the bottom of the installation cavity. The liquid inlet channel communicates with the lower end of the installation cavity so that when pressure oil is input into the liquid inlet channel, the piston body can be driven to move upward against the force of the spring.

[0009] In some embodiments, an annular cavity is formed at one end of the drill bit body away from the cutter blade. The liquid inlet channel communicates with the annular cavity. The annular cavity is provided with an annular rotating ring. The rotating ring is provided with a connector communicating with the annular cavity. The connector communicates with an external pipeline. The rotating ring is provided with a sealing end cover.

[0010] Compared with the prior art, the present invention has the following beneficial effects:

[0011] During the use of the core drill bit for rapid drilling of the present invention, when drilling in soft formations and clay formations, due to the relatively small cutting force of the cutting teeth on the cutter blade, pressure oil is injected into the annular cavity in the drill bit body. After the pressure oil enters the liquid inlet channel, it enters the lower part of the installation cavity, thereby driving the piston body to move upward against the resistance of the spring, and then driving the lower end of the piston body away from the second channel, so that the second channel is in an open state. On the one hand, the drilling fluid introduced into the main drilling fluid channel continuously flushes and cools each cutting tooth on the cutter blade through the first channel, and at the same time moves upward with the carried debris of the drilling fluid; on the other hand, the drilling fluid is ejected through the outlet in the second channel. Since the inclination direction of the second outlet is opposite to the rotation direction of the drill bit body, the drilling fluid ejected from the second channel collides with the floating debris, thereby crushing the debris again to form debris with a smaller particle size, which is conducive to the timely discharge of the debris, preventing it from adhering to the periphery of the cutter blade and the cutting teeth, and further preventing the problem of debris adhering to the cutter blade and the cutting teeth when drilling in soft formations and clay formations, so as to achieve the purpose of improving the drilling efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a schematic cross-sectional view structure diagram of an embodiment of the present invention;

[0013] Figure 2 is Figure 1 a schematic diagram of a partial enlarged view at A in

[0014] Figure 3 is Figure 1 a schematic diagram of a partial enlarged view at B in

[0015] Markings in the figure: 1. Drill bit body, 2. Blade, 3. Cutting tooth, 4. Core sampling channel, 5. Main drilling fluid channel, 6. First channel, 7. Second channel, 8. Liquid inlet channel, 9. Installation cavity, 10. Piston body, 11. Spring, 12. Annular cavity, 13. Rotating ring, 14. Connector, 15. Sealing end cover. Specific implementation manners

[0016] The present invention will be further described below in conjunction with embodiments. The described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the protection scope of the present invention.

[0017] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present invention; the terms "first", "second", "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance; in addition, unless otherwise clearly defined and limited, the terms "installation", "connection", "connection" 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; it can be directly connected, or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood in combination with specific situations.

[0018] Combined with the attached Figure 1 to the attached Figure 3, the core bit for rapid drilling of the present invention includes a bit body 1. The lower end of the bit body 1 has a plurality of cutter wings 2, and a plurality of cutting teeth 3 are installed on each cutter wing 2. Among them, the cutting teeth 3 include main cutting teeth and secondary cutting teeth. The size of the main cutting teeth is generally larger than that of the secondary cutting teeth. During the drilling process, the main cutting teeth play a major drilling role. The main cutting teeth are located at the lower part of the crown of the lower cutter wing, while the secondary cutting teeth are generally arranged at the upper end of the main cutting teeth (that is, the secondary cutting teeth are closer to the bit body than the main cutting teeth). Those skilled in the art can understand and comprehend this, and will not be elaborated here. A core-taking channel 4 is formed in the middle of the bit body 1. The core-taking channel 4 is mainly used to accommodate the core during the drilling process. A main drilling fluid channel 5 is opened on the bit body 1. The main drilling fluid channel 5 is communicated with a first channel 6 and a second channel 7. The outlet of the first channel 6 faces the direction of the main cutting teeth on the cutter wing 3. The outlet of the second channel 7 is located at the upper part of the cutter wing 2, and the outlet of the second channel 7 is obliquely downwardly opened at the upper part of the cutter wing 2, and the outlet direction of the second channel 7 is opposite to the rotation direction of the bit body 1.

[0019] In some embodiments, a control structure for controlling the opening and closing of the second channel 7 is arranged on the second channel 7.

[0020] Combined with the attached Figure 1 and the attached Figure 2 , in some embodiments, the control structure includes a liquid inlet channel 8 opened on the bit body 1 and an installation cavity 9. A piston body 10 is arranged in the installation cavity 9. There is a through hole between the installation cavity 9 and the second channel 7. The upper end of the piston body 10 is located in the installation cavity 9 and is in sealed cooperation with the inner wall of the installation cavity 9. The lower end of the piston body 10 can pass through the through hole and extend into the second channel 7. A spring 11 is arranged between the top of the piston body 10 and the bottom of the installation cavity 9. The liquid inlet channel 8 is communicated with the lower end of the installation cavity 9 so that when pressure oil is input into the liquid inlet channel 8, the piston body 10 can be driven to move upward by overcoming the acting force of the spring 11.

[0021] Combined with the attached Figure 2 , the piston body 10 is integrally in the shape of a large upper end and a small lower end. Sealing rings are installed at both the upper end and the lower end of the piston body. The sealing effect between the piston body 10 and the installation cavity 9 and between the piston body 10 and the through hole is realized through the sealing rings.

[0022] In the specific processing process, the bit body can adopt a modular structure, that is, first open the installation cavity 9 according to the designed structure, then install the piston body 10 and the spring 11 in the installation cavity, and then perform welding and assembly to form the overall bit body. During the processing and manufacturing, corresponding processing holes can also be opened first, and after the assembly is completed, the processing holes can be blocked, etc.

[0023] In some embodiments, an annular cavity 12 is formed at one end of the drill bit body 1 away from the cutter blade 2. The liquid inlet passage 8 is in communication with the annular cavity 12. The annular cavity 12 is provided with an annular rotating ring 13. A connector 14 communicating with the annular cavity 12 is provided on the rotating ring 13. The connector 14 is in communication with an external pipeline. The rotating ring 13 is provided with a sealing end cover 15. Through the structural design of the annular cavity and the rotating ring, when the core bit rotates, the pipeline outside the drill bit body 1 does not need to rotate therewith. Preferably, the rotating ring can be formed by splicing two semi-circular structures, and finally sealed by the sealing end cover 15. Preferably, wear-resistant sealing rings are provided on the contact surface between the rotating ring 13 and the drill bit body 1, and on the contact surface between the rotating ring and / or the connector 1 and the sealing end cover 15.

[0024] Preferably, grease holes are further provided between the wear-resistant sealing rings, and grease is injected into the grease holes to reduce the friction force during rotation.

[0025] Similarly, the main drilling fluid passage 5 can also adopt a structural design similar to that of the annular cavity 12, which will not be elaborated here.

[0026] During the use of the core bit for rapid drilling according to the present invention, when drilling in soft formations and clay formations, since the acting force during cutting by the cutting teeth on the cutter blade is small, pressure oil is injected into the annular cavity inside the drill bit body. After the pressure oil enters the liquid inlet passage, it enters the lower part of the installation cavity, so as to drive the piston body to move upward against the resistance of the spring, and then drive the lower end of the piston body away from the second passage, so that the second passage is in an open state; on the one hand, the drilling fluid introduced into the main drilling fluid passage continuously flushes and cools each cutting tooth on the cutter blade through the first passage, and at the same time moves upward with the carried debris of the drilling fluid; on the other hand, the drilling fluid is ejected from the outlet in the second passage. Since the inclination direction of the second outlet is opposite to the rotation direction of the drill bit body, the drilling fluid ejected from the second passage collides with the floating debris, so as to crush the debris again to form debris with a smaller particle size, which is beneficial to the timely discharge of the debris, prevent adhesion to the periphery of the cutter blade and the cutting teeth, and further prevent the problem of debris adhesion to the cutter blade and the cutting teeth when drilling in soft formations and clay formations, so as to achieve the purpose of improving the drilling efficiency.

Claims

1. A core bit for rapid drilling, comprising a bit body. The lower end of the bit body has a plurality of cutter wings, and a plurality of cutting teeth are installed on each cutter wing. A core-taking channel is formed in the middle of the bit body, and it is characterized in that, A main drilling fluid passage is provided on the drill bit body. The main drilling fluid passage is communicated with a first passage and a second passage. The outlet of the first passage faces the direction of the main cutting teeth on the cutter blade. The outlet of the second passage is located at the upper part of the cutter blade, and the outlet of the second passage is obliquely downwardly provided at the upper part of the cutter blade, and the outlet direction of the second passage is opposite to the rotation direction of the drill bit body; A control structure for controlling the opening and closing of the second passage is arranged on the second passage; the control structure includes a liquid inlet passage and an installation cavity provided on the drill bit body. A piston body is arranged in the installation cavity. There is a through hole between the installation cavity and the second passage. The upper end of the piston body is located in the installation cavity and is in sealing cooperation with the inner wall of the installation cavity. The lower end of the piston body can pass through the through hole and extend into the second passage. A spring is arranged between the top of the piston body and the bottom of the installation cavity. The liquid inlet passage is communicated with the lower end of the installation cavity so that when pressure oil is input into the liquid inlet passage, the piston body can be driven to move upward by overcoming the acting force of the spring.

2. The coring bit for rapid drilling according to claim 1, characterized in that, An annular cavity is provided at one end of the drill bit body far from the cutter blade. The liquid inlet passage is communicated with the annular cavity. The annular cavity is provided with an annular rotating ring. The rotating ring is provided with a joint communicated with the annular cavity. The joint is communicated with an external pipeline. The rotating ring is provided with a sealing end cover.

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