Drill bit special for mudstone drilling

Abstract

The utility model relates to a drill bit special for mudstone drilling, and belongs to the technical field of drilling for geological exploration. According to the technical scheme, the steel body and the tire body are included, the tire body is composed of a plurality of tire blocks (6) evenly arranged at the end of the steel body (1) in the circumferential direction, diamond is contained in the tire body, the space between every two adjacent tire blocks (6) is a main water gap (5), the upper end face of each tire block (6) is a lip face, and each lip face is of a step-shaped structure composed of an inner side face (61) and an outer side face (62). The inner side surface (61) is a fan-shaped annular plane, the plurality of polycrystalline bodies (4) are arranged on the fan-shaped annular plane, the polycrystalline bodies (4) are of conical structures, the outer side surface (62) is a downward inclined plane, and an auxiliary water gap (7) with an outward opening is formed in the tire block (6). The drill bit has the advantages of being easy to manufacture and simple in structure, solving the problem of adaptability of the drill bit to mudstone strata, and reducing the phenomena of collapse and bit pasting.

Description

Technical Field

[0001] This utility model relates to a special drill bit for drilling mudstone, and particularly to a drill bit for drilling mudstone, argillaceous sandstone and other strata in core drilling, belonging to the field of drilling technology for geological exploration. Background Technology

[0002] Conventional diamond core-taking bits can be categorized into alloy bits, composite bits, and diamond bits. Different types of bits are selected for different rock formations. Generally, alloy bits are used for rock formations of grades 1-3, composite bits for grades 2-6, and diamond bits for grades 5-9. Although different bits are designed for different rock formations, core sampling in mudstone and clay layers remains quite challenging. If core sampling is not required, roller cone bits and coreless composite bits are sufficient. However, choosing the right bit becomes crucial when core sampling is involved in soil layers.

[0003] Mud and clay layers. This formation is characterized by its looseness and instability. Drilling in this area is prone to problems such as borehole narrowing, collapse, and drill bit clogging. Generally, composite-blade drill bits with single-tube coring are used in these formations. The coring process is complex and labor-intensive. When using wireline coring, new drill bits often stop advancing or advance very slowly after only 3-5 meters. This is because as the drill bit advances, rock powder and flushing fluid mix, increasing the density of the mudstone at the bottom of the hole. This hinders water circulation, clogging the drill bit's cutting teeth and water passages. This slows down the drill bit's advance and affects drilling costs.

[0004] When a drill bit becomes clogged, the cutting tools and nozzles at the drill bit tip become filled with mud, reducing its cutting effectiveness against the formation. The bit spins in place, decreasing its drilling efficiency. The nozzles also experience reduced water flow capacity and cooling performance. As the drill bit temperature rises, the diamond or cutting tools are rapidly damaged at high temperatures, shortening the drill bit's lifespan. Under high pressure and temperature, the mud layer on the drill bit gradually becomes compacted until the drill bit fails. Therefore, preventing the cutting tools from becoming clogged and ensuring unobstructed flow at the nozzles are crucial for improving drill bit drilling efficiency and lifespan. Utility Model Content

[0005] The purpose of this invention is to provide a special drill bit for mudstone drilling, which improves the adaptability of wireline coring in mudstone or clay layers, increases the drill bit's advance speed, and solves the aforementioned problems in the prior art.

[0006] The technical solution of this utility model is:

[0007] A drill bit for drilling mudstone includes a steel body and a matrix. The matrix is ​​composed of multiple matrix blocks evenly arranged at the ends of the steel body along the circumferential direction. The matrix contains diamond. The space between two adjacent matrix blocks is the main water inlet. The upper end face of the matrix block is a lip face, which is a stepped structure composed of an inner side and an outer side. The inner side is a fan-shaped annular plane, and several polycrystals are arranged on the fan-shaped annular plane. The polycrystals have a conical structure. The outer side is a downwardly inclined slope. The matrix block is provided with an auxiliary water inlet with an opening facing outward.

[0008] Furthermore, the main water inlet is a conical water inlet that is narrow on the inside and wide on the outside, and the bottom surface of the main water inlet is an inclined surface that is high on the inside and low on the outside.

[0009] Furthermore, the end where the steel body connects to the tire body is a frustum-shaped powder discharge groove that is narrow at the top and wide at the bottom.

[0010] Furthermore, the auxiliary water inlet is a through groove structure located at the middle of the outer side of the tire block. The groove of the auxiliary water inlet faces outward, and the top of the auxiliary water inlet is located on the outer side of the upper end face of the tire block. The bottoms of both the auxiliary water inlet and the main water inlet are connected to the frustum-shaped powder discharge groove.

[0011] Furthermore, the polycrystal has a conical structure.

[0012] Furthermore, the longitudinal section of the polycrystal is triangular.

[0013] The positive effects of this invention are as follows: the conical polycrystalline material at the end of the drill bit is equivalent to a plowshare. The sharp end first breaks through the mudstone layer and crushes it. The matrix contains diamond, which then cuts the crushed mudstone, enabling rapid drilling. The auxiliary water inlet not only increases the drainage path, but also reduces the area of ​​the outer surface due to its design, thereby reducing the cutting surface area of ​​the drill bit. This allows the drill bit to advance rapidly and reduces the occurrence of collapse and drill jamming. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the structure of this utility model;

[0015] In the diagram: 1. Steel body; 2. Frustum-shaped powder discharge trough; 3. Bottom surface; 4. Polycrystalline material; 5. Main water inlet; 6. Tire block; 61. Inner side surface; 62. Outer side surface; 7. Secondary water inlet. Detailed Implementation

[0016] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0017] A special drill bit for drilling mudstone includes a steel body 1 and a matrix. The matrix is ​​composed of multiple matrix blocks 6 evenly arranged at the ends of the steel body 1 along the circumferential direction. The matrix contains diamond. The space between two adjacent matrix blocks 6 is the main water inlet 5. The upper end face of the matrix block 6 is a lip face, which is the cutting surface of the drill bit. The lip face is a stepped structure composed of an inner side face 61 and an outer side face 62. The inner side face 61 is a fan-shaped annular plane. Several polycrystals 4 are arranged circumferentially on the fan-shaped annular plane. The polycrystals 4 have a conical structure. The outer side face 62 is a downwardly inclined slope. The matrix block 6 is provided with an auxiliary water inlet 7 with an opening facing outward.

[0018] See attached document Figure 1 In this embodiment, there are six jig blocks 6. The six jig blocks 6 are evenly arranged at the end of the steel body 1 along the circumferential direction. The outer surface 62 of the six jig blocks 6 form a conical surface. When the drill bit is pressurized and advances, the conical surface of the lip has an outward squeezing force, which squeezes the rock and soil adhered to the drill bit surface out of the bottom of the hole through the accumulated pressure of the drill bit and the bottom of the hole to prevent the drill bit from getting stuck.

[0019] Preferably, the number of main water inlets 5 is 6-12, and the width is 6-12mm. In this embodiment, the number of main water inlets 5 is 6.

[0020] Because the inner width of the main water inlet 5 is smaller than the outer width, and the bottom surface 3 of the main water inlet 5 is a sloping surface with an inner higher surface and an outer lower surface, the main water inlet 5 becomes a conical water inlet. The design of the conical water inlet prevents rock powder at the bottom of the hole from clogging the main water inlet and thus stopping the drill bit from advancing.

[0021] The end where the steel body 1 connects to the matrix is ​​a frustum-shaped powder discharge groove 2 that is narrow at the top and wide at the bottom. The outer wall of the frustum-shaped powder discharge groove 2 has an inclination angle of 5-15 degrees. The purpose of adopting a frustum-shaped design at the contact end between the steel body 1 and the matrix is ​​to accelerate the removal of rock powder from the bottom of the hole and reduce the impact on the drill bit.

[0022] The auxiliary water inlet 7 is a through-groove structure located in the middle of the outer side of the jig block 6, with a depth of 5-10mm. The groove of the auxiliary water inlet 7 faces outward, and the top of the auxiliary water inlet 7 is located on the outer side 62 of the upper end face of the jig block 6. The bottoms of both the auxiliary water inlet 7 and the main water inlet 5 are connected to the frustum-shaped powder discharge groove 2. The auxiliary water inlet 7 not only increases the drainage path, but also reduces the area of ​​the outer side 62 due to its design, thereby reducing the cutting surface area of ​​the drill bit and enabling the drill bit to advance quickly.

[0023] The polycrystalline material 4 has a conical structure and is a 4*4*5mm high-consumption-ratio polycrystalline material, ensuring rapid drill bit advance.

[0024] The drill bit of this utility model adopts an enlarged outer diameter design, increasing the original 75mm diameter drill bit by 5-10mm. The purpose is to increase the gap between the hole diameter and the drill rod, which is beneficial for the removal of rock powder.

[0025] The steel body 1 is made of 42CrMo steel to increase its wear resistance. The matrix is ​​sintered using a carbide alloy, and diamond with a particle size of 30 / 60 is placed inside the matrix. This invention uses automatic medium-frequency sintering to bond the matrix and the steel body 1, and then slowly cools down after reaching the sintering temperature.

[0026] This invention employs a "ploughing" principle to break rock before cutting. In mudstone drilling, the "ploughing" principle is similar to tilling land with a plow. In this invention, the conical polycrystalline material at the drill bit's end acts as a plowshare; the sharp tip first breaks through the mudstone layer, fracturing it. The matrix contains diamond, which then cuts the broken mudstone, enabling rapid drilling. The drill bit features an external conical surface design, which reduces drilling resistance and increases drilling speed when drilling through mudstone.

[0027] In this invention, the two adjacent blocks 6 are completely disconnected, and the space between the disconnected blocks is the main water inlet 5. The water passage gap between the rock layer and the block is larger, which is conducive to the rapid removal of broken particles by the water flow, thereby preventing drill jamming and achieving rapid drilling.

[0028] In this invention, the polycrystalline material 4 is a large-grained square polycrystalline material. With its conical surface facing outwards, it is placed only at the very front of the drill bit. When drilling into mudstone formations, it acts like a plowshare, cutting and segmenting the mudstone to ensure rapid drill bit advance. The main water inlet 5, as shown in the figure, is a conical inlet that is narrower on the inside and wider on the outside. This shape helps the cleaning fluid quickly remove mudstone from the bottom of the hole during mudstone drilling; the enlarged design of the main water inlet 5 serves this purpose.

[0029] Through actual testing on the machine, this utility model demonstrates that this type of drill bit has excellent drilling performance in core samples taken from mudstone and clay layers, greatly reducing drilling costs. It also reduces the frequent up-and-down drilling of the drill bit in mudstone formations, thereby improving drilling efficiency and lowering drilling costs.

Claims

1. A drill bit specifically designed for drilling mudstone, characterized in that: It includes a steel body (1) and a matrix. The matrix is ​​composed of multiple matrix blocks (6) evenly arranged at the ends of the steel body (1) along the circumferential direction. The matrix contains diamond. The space between two adjacent matrix blocks (6) is the main gate (5). The upper end face of the matrix block (6) is a lip surface. The lip surface is a stepped structure composed of an inner side surface (61) and an outer side surface (62). The inner side surface (61) is a fan-shaped annular plane. Several polycrystals (4) are arranged on the fan-shaped annular plane. The polycrystals (4) are conical structures. The outer side surface (62) is a downward inclined surface. The matrix block (6) is provided with an outward-facing auxiliary gate (7).

2. The drill bit for drilling mudstone according to claim 1, characterized in that: The main water inlet (5) is a conical water inlet that is narrow on the inside and wide on the outside, and the bottom surface (3) of the main water inlet (5) is an inclined surface that is high on the inside and low on the outside.

3. A special drill bit for mudstone drilling according to claim 1 or 2, characterized in that: The end of the steel body (1) connected to the tire body is a frustum-shaped powder discharge groove (2) that is narrow at the top and wide at the bottom.

4. A special drill bit for mudstone drilling according to claim 3, characterized in that: The auxiliary water inlet (7) is a through groove structure located in the middle of the outer side of the tire block (6). The groove of the auxiliary water inlet (7) faces outward, and the top of the auxiliary water inlet (7) is located on the outer side (62) of the upper end face of the tire block (6). The bottoms of the auxiliary water inlet (7) and the main water inlet (5) are connected to the frustum-shaped powder discharge groove (2).

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