Coring drill bit with replaceable blades

Abstract

The invention belongs to the technical field of geological survey, particularly relates to a blade-replaceable coring drill bit, and aims to solve the problems that a fixed blade coring drill bit is short in service life and poor in adaptability. The drill bit comprises a hollow drill bit base body, wherein a split type replaceable blade is arranged at a tool bit drilling part of the drill bit base body; the blades are detachably fixed to the lower end of the drill bit base body through fastening devices. An inner cavity of the drill bit base body is of a step-shaped expanding structure from the front end to the rear portion. Wherein the blade is provided with a groove matched with the outline of the lower end of the drill bit base body, the blade is connected with the lower end of the drill bit base body through the groove, the blade and the drill bit base body are fastened through a fastening device, and the fastening device comprises a mechanical connecting structure penetrating through the blade and the drill bit base body. The device has the advantages of being simple in structure, rapid to disassemble, long in service life and reliable in work.

Description

Technical Field

[0001] This invention belongs to the field of geological exploration technology, and specifically relates to a replaceable blade coring drill bit. Background Technology

[0002] In geological exploration and drilling engineering, core drill bits are an important tool for obtaining underground rock core samples.

[0003] Traditional core drill bits typically have fixed, non-replaceable blades. Before production, the inner and outer diameters of the core drill bit need to be determined. Once individual blades are worn or damaged, the entire drill bit often becomes unusable.

[0004] Moreover, the fixed blade design is less adaptable to different geological conditions and cannot meet diverse drilling needs.

[0005] Furthermore, when the core drill bit body is made of steel, due to the characteristics of its product structure, it is difficult to machine a hole perpendicular to the axis of the core drill bit at the position of its inner diameter teeth. Usually, a cemented carbide with a poor wear resistance grade is used instead of diamond composite sheets, resulting in poor wear resistance and a correspondingly shorter service life of the core drill bit. Summary of the Invention

[0006] To address the aforementioned problems in the prior art, namely the short service life and poor adaptability of fixed-blade core drills, this invention provides a replaceable-blade core drill, wherein the drill bit base has a split-type replaceable blade at the drill bit entry section.

[0007] The blade is detachably fixed to the lower end of the drill bit body by a fastening device;

[0008] The inner cavity of the drill bit base has a stepped expansion structure from the front end to the rear end;

[0009] The cutter wing is provided with a groove that matches the lower end contour of the drill bit base. The cutter wing is connected to the lower end of the drill bit base through the groove and is fastened to the drill bit base by a fastening device. The fastening device includes a mechanical connection structure that penetrates the cutter wing and the drill bit base. The portion of the cutter wing located inside the drill bit base is provided with an inner diameter protection part, and the inner diameter protection part is provided with inner diameter protection teeth.

[0010] Furthermore, the cutter blade is provided with a groove that matches the lower end contour of the drill bit body, and the fastening device includes:

[0011] The outer diameter protection connection hole is located on the outer diameter protection part of the blade wing;

[0012] The inner diameter protection threaded hole is provided in the inner diameter protection part of the blade wing;

[0013] The base connection hole is provided in the drill bit body;

[0014] The connecting bolts pass through the outer diameter connecting hole and the base connecting hole in sequence and are threadedly fastened to the inner diameter threaded hole.

[0015] Furthermore, retaining rings and nuts are used to tighten the heads of connecting bolts.

[0016] Furthermore, the outer surface of the blade is covered with a wear-resistant weld overlay layer.

[0017] Furthermore, the outer diameter portion is fitted with outer diameter teeth of a diamond composite sheet structure.

[0018] Furthermore, the cutting end of the blade is fitted with cutting teeth of a diamond composite structure.

[0019] Furthermore, the inner diameter portion is fitted with inner diameter teeth of a diamond composite sheet structure.

[0020] Furthermore, the diamond composite sheet structure includes an alloy tooth body and a diamond cutting layer welded to the top of the alloy tooth body.

[0021] Furthermore, the upper inner surface of the drill bit base is provided with an internal thread for connection with the drill rod.

[0022] Furthermore, the cutter wing is an independent single-wing structure, with multiple single-wings distributed circumferentially along the drill bit base.

[0023] The beneficial effects of this invention are:

[0024] (1) The replaceable blade type core drill bit of the present invention has stronger adaptability by setting detachable blades. The core drill bit of the present invention uses a base body and can achieve the technical purpose of changing the drill bit head shape, number of blades, outer diameter and inner diameter by changing the blades, or can achieve the effect of quickly repairing the drill bit by replacing the damaged blades.

[0025] (2) The replaceable blade type core drill bit of the present invention can be a structure of several blades integrated together or a single blade structure. By using the arc-shaped tube wall of the drill bit base combined with the bolt fastening structure, sufficient cutting strength and rigidity can be provided to the detachable blade of the present invention. Attached Figure Description

[0026] Other features, objects, and advantages of this application will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0027] Figure 1 This is a schematic diagram of the replaceable blade type core drill bit of the present invention;

[0028] Figure 2This is a schematic diagram of the drill bit body of the present invention;

[0029] Figure 3 This is a schematic diagram of the replaceable blade.

[0030] Figure label:

[0031] 1-Drill bit body, 2-Cutter blade, 3-Upper part of the body, 4-Lower part of the body, 5-Pipe thread, 6-Body connecting hole, 7-Weld overlay, 8-Cutting tooth, 9-Outer diameter protection part, 10-Outer diameter protection tooth, 11-Inner diameter protection part, 12-Inner diameter protection tooth, 13-Outer diameter protection connecting hole, 14-Inner diameter protection threaded hole, 15-Retaining ring groove, 16-Connecting bolt, 17-Bolt thread end, 18-Nut, 19-Retaining ring, 20-Bolt top. Detailed Implementation

[0032] The present application will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the invention. Furthermore, it should be noted that, for ease of description, only the parts relevant to the invention are shown in the accompanying drawings.

[0033] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0034] This invention provides a replaceable blade type core drill bit.

[0035] like Figure 1 The image shows the replaceable blade type core drill bit of the present invention. Figure 2 This is a schematic diagram of the drill bit base structure. Figure 3 This is a schematic diagram of the blade wing structure.

[0036] The replaceable blade type core drill bit of the present invention includes a drill bit body 1, wherein the drill bit body 1 is provided with a split replaceable blade 2 in the drill bit drilling part;

[0037] The blade 2 is detachably fixed to the lower end of the drill bit base 1 by a fastening device;

[0038] The inner cavity of the drill bit base 1 has a stepped expansion structure from the front end to the rear end;

[0039] The cutter wing 2 is provided with a groove that matches the lower contour of the drill bit base 1. The cutter wing 2 is connected to the lower end of the drill bit base 1 through the groove, and the cutter wing 2 is fastened to the drill bit base 1 by a fastening device. The fastening device includes a mechanical connection structure that penetrates the cutter wing 2 and the drill bit base 1. The portion of the cutter wing 2 located inside the drill bit base 1 is provided with an inner diameter protection part 11, and the inner diameter protection part is provided with inner diameter protection teeth 12.

[0040] The stepped inner cavity of the drill bit body 1 is designed to facilitate the removal of drilled rock cores. The size of the inner cavity gradually increases from the front end to the rear end of the drill bit.

[0041] Specifically, the stepped, enlarging inner cavity forms a gradually widening channel, significantly reducing the frictional resistance between the core sample and the drill bit's inner wall, preventing core blockage or jamming, and ensuring the continuity of the coring process. The stepped transition structure provides expansion buffer space for the core, preventing it from fracturing due to thermal expansion or stress concentration, thus improving the integrity of the core sample and the quality of the coring. The enlarged inner cavity enhances the drilling fluid's backflow efficiency, promptly removing cuttings and cooling the drill bit, reducing blade wear and overheating risks.

[0042] In this embodiment, the upper inner cavity surface of the drill bit base 1 is provided with an internal thread for connecting with the drill rod. The internal thread is also a pipe thread 5. Specifically, the inner tube wall of the upper part 3 of the drill bit base 1 is provided with a pipe thread 5 for fastening connection with the drill rod.

[0043] The fastening device includes:

[0044] The outer diameter protection connection hole 13 is provided on the outer diameter protection part 9 of the blade 2;

[0045] An inner diameter threaded hole 14 is provided in the inner diameter protection part 11 of the blade 2;

[0046] The base connection hole 6 is provided in the drill bit base 1;

[0047] The connecting bolt 16 passes through the outer diameter connecting hole 13 and the base connecting hole 6 in sequence and is threadedly fastened to the inner diameter threaded hole 14.

[0048] In this embodiment, the lower part 4 of the drill bit base 1 is provided with a base connection hole 6 for fastening and connecting the cutter blade 2.

[0049] Specifically, a number of base connection holes 6 are evenly distributed in the circumferential direction of the drill bit base 1, which correspond to the outer diameter protection connection hole 13 and the inner diameter protection threaded hole 14 of the cutter wing 2, and are fastened together by connecting bolts 16.

[0050] In this embodiment, the fastening device further includes a retaining ring 19 and a nut 18 for pressing the head of the connecting bolt 16.

[0051] In this embodiment, the outer surface of the blade 2 is provided with a weld overlay layer 7, and a diamond composite cutting tooth 8 is embedded in the cutting end. An outer diameter protection part 9 is provided on the outer side of the replaceable blade 2, and an outer diameter protection tooth 10 is provided on the outer diameter protection part 9. An inner diameter protection part 11 is provided on the inner side, and an inner diameter protection tooth 12 is provided on the inner diameter protection part 11.

[0052] The basic structure of the replaceable blade 2 can be made of cemented carbide material.

[0053] The cutting tooth 8, the outer diameter protection tooth 10, and the inner diameter protection tooth 12 are preferably composite diamond sheet structure teeth.

[0054] The diamond composite sheet structure in this embodiment includes an alloy tooth body and a diamond cutting layer welded to the top of the alloy tooth body. The alloy tooth body is preferably a cemented carbide tooth body.

[0055] In this embodiment, an outer diameter protection connection hole 13 is provided on the outer diameter protection portion 9 of the blade 2, and an inner diameter protection threaded hole 14 is provided on the inner diameter protection portion 11 to match it. Both the outer diameter protection connection hole 13 and the inner diameter protection threaded hole 14 are matched with the base connection hole 6 on the drill bit base 1.

[0056] During installation, the connecting bolts 16 are sequentially inserted into the outer diameter-protecting connecting hole 13 and the base connecting hole 6, and the threaded end 17 of the bolts is engaged and tightened with the inner diameter-protecting threaded hole 14.

[0057] The outer end of the outer retaining diameter connecting hole 13 is provided with a retaining ring groove 15. During installation, the retaining ring 19 is placed in the retaining ring groove 15 and tightened with the nut 18. The depth of the retaining ring groove 15 should ensure that the outer end of the nut 18 of the connecting bolt 16 is lower than the plane of the outer retaining diameter portion 9. In other words, the top 20 of the bolt is at least on the same plane as the plane of the retaining diameter portion 9.

[0058] The preferred embodiment of the blade 2 of the present invention is a single blade body structure, that is, the blade bodies of a core drill bit are divided into several blades 2. During installation, the blades 2 are installed sequentially on the drill bit base 1. With this single blade body structure, when the blades need to be replaced due to wear or breakage, only the damaged blades can be replaced, which is more economical.

[0059] In this invention, the blade 2 may also consist of two, three, or more blades, with the multiple blades 2 distributed circumferentially along the drill bit base 1. Specifically, they may be evenly distributed circumferentially.

[0060] In this invention, the blade 2 can also be an integrated blade structure, that is, several blades 2 of a core drill bit are an integrated structure. During installation, the lower end of the drill bit base 1 is inserted into the groove of the blade 2, and then fastened in sequence with connecting bolts 16.

[0061] In another embodiment of the present invention, a dynamic control method for a replaceable blade coring drill bit is proposed, the method comprising:

[0062] Step S1: Obtain the geological hardness data of the drilled formation and classify the formation type based on the preset hardness grading rules;

[0063] Step S2: Dynamically configure the number of cutter wings according to the formation type; wherein, the number of cutter wings increases with the increase of formation hardness;

[0064] Step S3: Based on the formation type, and according to the predefined mapping relationship between formation type and drilling speed and pressure, synchronously match the range of drill bit rotation speed and the range of drilling pressure.

[0065] The mapping relationship satisfies the following: the set value of the drill bit rotation speed decreases as the hardness value of the formation increases; the set value of the drill bit drilling pressure increases as the hardness value of the formation increases.

[0066] Step S4: Monitor the mechanical drilling speed decay rate and temperature data of the cutter blade in real time. Trigger a wear warning when any data exceeds the preset safety threshold.

[0067] Step S5: In response to the wear warning, selectively replace the target worn blades to maintain the dynamic balance of the drill bit;

[0068] Step S6: When the local layer type changes, repeat steps S2-S5.

[0069] For step S1, it specifically includes:

[0070] S11. Real-time data on formation compressive strength and rock density are collected using near-bit sensors, acoustic probes, or resistivity meters in the measurement while drilling system.

[0071] S12. Use machine learning algorithms to identify stratigraphic boundaries in the collected data and update stratigraphic type labels at a cycle of 0.5 seconds.

[0072] S13. Hardness classification is performed according to the compressive strength value of the formation: Grade I (<50MPa), Grade II (50-100MPa), Grade III (100-150MPa), Grade IV (150-200MPa), Grade V (>200MPa).

[0073] In this embodiment, during drilling, a measurement-while-drilling system (such as a near-bit sensor, acoustic probe, or resistivity meter) collects parameters such as formation compressive strength and rock density in real time, forming a continuous stream of geological hardness data. The data processing unit, based on preset hardness grading rules (e.g., dividing hardness into grades I-V, where grade I corresponds to soft sandstone <50 MPa and grade V corresponds to hard granite >200 MPa), uses machine learning algorithms to intelligently identify formation boundaries, updating formation type labels every 0.5 seconds. Simultaneously, a formation hardness profile is established to provide a basis for subsequent dynamic control.

[0074] For step S2, the specific steps include: the control system has a built-in cutter wing configuration strategy library, which automatically matches the optimal number of cutter wings according to the formation type: in soft formations of grade I-II, 2-4 sets of cutter wings are used to improve cutting efficiency; in hard formations of grade III, 4-6 sets of cutter wings are switched to balance drilling speed and wear; in hard formations of grade IV-V, only 6-8 sets of cutter wings are deployed to enhance the single tooth penetration depth.

[0075] Step S4: Monitor the mechanical drilling speed decay rate and temperature data of the cutter blade in real time. Trigger a wear warning when any data exceeds the preset safety threshold.

[0076] Specifically, the instantaneous mechanical rate of drilling (ROP) is acquired in real time using a measurement-while-drilling (MWD) tool, and the attenuation rate is calculated as follows:

[0077] Attenuation rate = (current ROP - baseline ROP) / feed length × 100%; wherein, the temperature data is obtained based on a temperature sensor, which is embedded in the inner tube assembly or outer tube of the coring tool near the drill bit.

[0078] In the description of this invention, terms such as "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," which indicate direction or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. These are used merely for ease of description and do not indicate or imply that the device or element 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. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0079] Furthermore, it should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" 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 or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0080] The term "comprising" or any other similar term is intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus / device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent in such process, method, article, or apparatus / device.

[0081] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. A replaceable blade type core drill bit, comprising a hollow drill bit body, characterized in that: The drill bit body has a split, replaceable blade in the cutting section; The blade is detachably fixed to the lower end of the drill bit body by a fastening device; The inner cavity of the drill bit base has a stepped expansion structure from the front end to the rear end; The cutter wing is provided with a groove that matches the lower end contour of the drill bit base. The cutter wing is connected to the lower end of the drill bit base through the groove, and the cutter wing is fastened to the drill bit base by a fastening device. The fastening device includes a mechanical connection structure that penetrates the cutter wing and the drill bit base. The portion of the cutter blade located inside the drill bit body is provided with an inner diameter protection section, and the inner diameter protection section is provided with inner diameter protection teeth.

2. The replaceable blade type core drill bit as described in claim 1, characterized in that: The fastening device includes: The outer diameter protection connection hole is located on the outer diameter protection part of the blade wing; The inner diameter protection threaded hole is provided in the inner diameter protection part of the blade wing; The base connection hole is provided in the drill bit body; The connecting bolts pass through the outer diameter connecting hole and the base connecting hole in sequence and are threadedly fastened to the inner diameter threaded hole.

3. The replaceable blade type core drill bit as described in claim 2, characterized in that: The fastening device also includes a retaining ring and a nut for pressing the head of the connecting bolt.

4. The replaceable blade type core drill bit as described in claim 2, characterized in that: The outer surface of the blade is covered with a wear-resistant weld overlay layer.

5. The replaceable blade type core drill bit as described in claim 2, characterized in that: The outer diameter protection part is fitted with outer diameter protection teeth with a diamond composite sheet structure.

6. The replaceable blade type core drill bit as described in claim 1, characterized in that: The cutting end of the blade is fitted with cutting teeth with a diamond composite structure.

7. The replaceable blade type core drill bit as described in claim 2, characterized in that: The inner diameter protection part is fitted with inner diameter protection teeth with a diamond composite sheet structure.

8. The replaceable blade type core drill bit as described in any one of claims 5-7, characterized in that: The diamond composite sheet structure includes an alloy tooth body and a diamond cutting layer welded to the top of the alloy tooth body.

9. The replaceable blade type core drill bit as described in any one of claims 1, characterized in that: The upper inner surface of the drill bit base is provided with an internal thread for connection with the drill rod.

10. The replaceable blade type core drill bit as described in any one of claims 1, characterized in that: The cutter blade is an independent single-blade structure, with multiple single blades distributed circumferentially along the drill bit base.

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