A PDC drill bit with dual flow channel structure

Abstract

The present invention discloses a PDC drill bit with a dual-channel structure, belonging to the technical field of drilling equipment. The PDC drill bit with a dual-channel structure of the present invention includes an integrated drill body, blades, a gauge guard and an isolation blade. Several blades are distributed on the top circumference of the drill body, the lower part of the blades are connected with a gauge guard, the upper part of the blades are provided with cutting teeth that are beneficial to cutting rocks, and a chip removal channel is formed between two adjacent blades. The dual-channel isolation blade is in the shape of a three-dimensional curved surface structure and is installed in the gauge guard section of the channel groove. The blade divides the channel groove into an inner channel and an outer channel. The outer channel has a wide inlet and a narrow outlet, and gradually shrinks; the inner channel has a narrow inlet and a wide outlet, and gradually expands. The outer channel can effectively block heavy rock chips and crush large rock chips at the outlet end, which can enhance the outer ring jet lifting force, enhance the inner ring flow rate, improve drilling efficiency, and reduce the probability of drill jamming accidents caused by rock chips falling into the chip removal groove during the rock breaking process of the PDC drill bit.

Description

Technical Field

[0001] The invention belongs to the field of drilling technology such as petroleum and natural gas engineering, rock and soil and foundation engineering, underground mining engineering, etc., and specifically relates to a PDC drill bit with a double flow channel structure. Background Art

[0002] The drill bit is a tool used to break rocks to form a wellbore in drilling projects. Currently, the drill bits commonly used in drilling projects include three-cone drill bits, PDC drill bits, and cone-PDC composite drill bits. Among them, the PDC drill bit is the most commonly used drilling tool in oil drilling projects.

[0003] PDC drill bit (Polycrystalline Diamond Compact Bit) is a cutting drill bit made of polycrystalline diamond composite sheets embedded in the drill bit steel body (or welded to the drill bit matrix). It uses polycrystalline diamond composite sheets as cutting edges and crushes rocks by negative rake angle shearing. Existing PDC drill bits are all blade-wing drill bits, with a number of blades distributed circumferentially on the drill bit body, and PDC cutting teeth welded on the blades. A chip discharge channel is formed between two adjacent blades. During the drilling process, if the lifted rock cuttings fall into the well, they are easily stuck in the chip discharge groove, affecting the lifting and discharge of the rock cuttings, and further affecting the rock breaking efficiency of the drill bit.

[0004] After a long period of operation, blade-type PDC drill bits have problems such as nozzle clogging and difficulty in chip removal, which affect the rock breaking ability of the drill bit and reduce the rock breaking efficiency. Therefore, improving the chip removal ability at the bottom of the well is of great significance to improving drilling efficiency. In the structural design of the drill bit, improvements are made to the shape and size of the chip groove, such as widening the chip groove and reducing the length of the chip groove, which can alleviate the chip removal problem to a certain extent. Reducing the number and thickness of blades can increase the width of the chip groove. However, the number of blades determines the density and number of cutting teeth, which needs to be designed according to drilling conditions and geological conditions. Reducing the thickness of the blade will affect the strength of the drill bit, and reducing the thickness of the blade will easily lead to blade breakage during drilling. Reducing the length of the blade and the gauge section can reduce the length of the chip groove, but the length of the blade also needs to be designed according to drilling conditions and geological conditions. The gauge section is connected to the blade, and the gauge can increase the life of the drill bit and play a role in maintaining the wellbore diameter, so the shape and size of the gauge strip or gauge block also need to be designed according to drilling conditions and geological conditions. Summary of the invention

[0005] The purpose of the invention is to propose a PDC drill bit with a dual flow channel structure to address the above-mentioned problems, thereby reducing the probability of large rock chips falling into the chip groove to hinder the discharge of rock chips and even causing the drill bit to get stuck during the rock breaking process, thereby effectively improving the rock breaking efficiency of the drill bit.

[0006] In order to achieve the above-mentioned purpose, the present invention specifically adopts the following technical solutions:

[0007] The PDC drill bit with a dual-channel structure of the present invention comprises a drill bit body, blades, a gauge guard and an isolation blade, and is characterized in that: the drill bit, blades, gauge guard and isolation blade are an integral whole, a plurality of blades are distributed on the top circumference of the drill bit body, the lower parts of the blades are connected with gauge guards, the upper parts of the blades are provided with cutting teeth which are beneficial to cutting rocks, a chip removal channel is formed between two adjacent blades, the isolation blade is in the shape of a curved surface, is arranged in the channel, is connected with two adjacent blades, the upper part of the isolation blade is close to the top of the drill bit body, and the lower part is close to the end face of the gauge guard section, and the whole blade has a certain inclination angle in the channel.

[0008] In the above scheme, the isolation blade is a curved surface, one end of which is located at the blade shoulder and the other end is located at the diameter-keeping section. The upper end surface is a curved structure, which does not affect the loading and unloading of the nozzle and does not hinder the normal operation of the nozzle. The lower end is connected to two adjacent diameter-keeping sections.

[0009] The isolation blade is entirely located in the chip groove, with the upper portion of the blade close to the top of the drill body and the lower portion close to the outer end surface of the gauge section, dividing the chip groove into two inner and outer flow channels, thereby playing a role in diverting cuttings.

[0010] The transverse curved surface of the isolation blade is streamlined, which can effectively reduce the resistance when the fluid passes through.

[0011] The thickness of the lower section of the isolation blade is greater than that of the upper section, so that it has greater strength to cope with the extrusion of large rock chips.

[0012] The isolation blades are tempered to increase their hardness, and diamond or cemented carbide particles are embedded on the outer curved surface to effectively crush rocks during the fluid extrusion process.

[0013] In the process of rock breaking by the drill bit, due to the centrifugal force, the heavy cuttings tend to the outer circle of the chip groove, while the light cuttings tend to the inner circle of the chip groove. Therefore, the chip groove is designed with inner and outer double channels, so that the light cuttings are discharged from the inner channel and the heavy cuttings are discharged from the outer channel. The outer channel has a wide entrance and a narrow exit, so that the heavy cuttings will be crushed in the channel, forming a pressure difference at the exit of the channel groove, so that the fluid in the channel groove forms a compression-injection-expansion pressurization and depressurization process, which increases the outer circle injection lifting force and the inner circle fluid flow rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The present invention will be further described by way of the accompanying drawings and specific embodiments, in which:

[0015] Figure 1 It is a schematic diagram of the structure of the PDC drill bit of the present invention.

[0016] Figure 2 It is a schematic diagram of the installation position of the isolation blade of the present invention.

[0017] Figure 3 It is a schematic diagram of the double flow channel structure of the present invention.

[0018] Figure 1 , Figure 2 Middle marking: 1-drill body, 2-blade, 3-gauge guard, 4-isolating blade, 5-cutting tooth, 6-chip groove. Figure 3 Marking 301-inner flow channel, 302-outer flow channel. DETAILED DESCRIPTION

[0019] In order to more clearly demonstrate the purpose, technical solution and advantages of the present invention, the present invention is further explained below in conjunction with the accompanying drawings and embodiments. It is particularly noted that the described embodiments are used to explain the present invention and are not limited to this embodiment.

[0020] Figure 1 The structure of the PDC drill bit with a dual-channel structure of the present invention is shown, including a drill body 1, blades 2, a gauge 3 and an isolation blade 4, and is characterized in that: the drill body 1, blades 2, gauge 3 and isolation blades 4 are a whole, a plurality of blades 2 are distributed on the top circumference of the drill body, the lower parts of the blades 2 are connected with gauges 3, the upper parts of the blades 2 are provided with cutting teeth 5 which are beneficial to cutting rocks, and a chip groove 6 is formed between two adjacent blades 2. The isolation blade 4 is in the shape of a curved surface, is arranged in the chip groove 6, is connected to two adjacent blades 2, its upper part is close to the top of the drill body, and its lower part is close to the end face of the gauge section, and the whole blade has a certain inclination angle in the channel.

[0021] Figure 2 The installation position of the isolation blade 4 of the dual-channel PDC drill bit of the present invention is shown. The installation positions of the isolation blades 4 in the chip groove 6 are basically the same. The left and right sides of the blades are distributed on two adjacent blades 2, but the upper end heights are inconsistent, forming a curve at the upper end. The isolation blades are streamlined, which can reduce the resistance of the structure in the fluid and does not affect the normal rock breaking efficiency.

[0022] Figure 3The display shows the inner and outer flow channels of the dual-channel structure PDC drill bit of the present invention. The isolation blade 4 is a curved surface, which divides the chip groove into two inner and outer flow channels. The inner flow channel 301 has a narrow entrance and a wide exit, so that small-mass cuttings can be discharged normally. The outer flow channel 302 has a wide entrance, which can effectively separate large-mass cuttings, so that large-mass cuttings can enter the outer flow channel as much as possible. The exit of the outer flow channel 302 gradually narrows, and the large-mass cutting fluid undergoes a compression process in the outer flow channel, so that the large-mass cuttings are crushed and finally ejected at the exit of the outer flow channel 302. Moreover, under the pressure difference at the exit of the chip groove, the flow rate of the fluid in the inner flow channel 301 will also increase, effectively reducing the probability of cuttings falling into the chip groove during the drilling process of the drill bit and causing a drill jam.

[0023] What is described above is a preferred embodiment of the present invention, but the present invention is not limited to the specific details of the above embodiment. Within the technical concept of the present invention, the technical solution of the present invention can be appropriately modified or multiple equivalent transformations can be made, and these modifications are all included in the protection scope of the present invention.

Claims

1. A PDC drill bit with a dual flow channel structure, comprising a drill bit body (1), a blade (2), a gauge guard (3) and a spacer blade (4), characterized in that: The drill body (1), blade (2), gauge guard (3) and isolation blade (4) are integrated into a whole. A plurality of blades (2) are distributed on the top circumference of the drill body. The lower parts of the blades (2) are connected to the gauge guard (3). The upper parts of the blades (2) are provided with cutting teeth (5) that are beneficial to cutting rocks. A chip removal groove (6) is formed between two adjacent blades (2). The isolation blade (4) is in the shape of a three-dimensional curved surface, is arranged in the chip removal groove (6), and is connected to two adjacent blades (2). The upper part of the isolation blade (4) is close to the top of the drill body, and the lower part is close to the end face of the gauge guard. The entire blade has a certain inclination angle in the flow channel. The outer end face of the isolation blade (4) is a curved surface, and one end of the left and right ends is higher than the other end. The end is low, so that the upper end of the isolation blade (4) is a curved structure, which does not affect the loading and unloading and operation of the nozzle, and the transverse surface of the isolation blade (4) is streamlined; the isolation blade (4) has a certain inclination angle, which divides the chip groove (6) into two inner and outer flow channels, the inner flow channel has a narrow inlet and a wide outlet, and the outer flow channel has a wide inlet and a narrow outlet. In view of the three-dimensional curved surface structure of the isolation blade (4), the axial inclination angle α of the blade at the inlet section of the flow channel should be set at 30°-45°, and the axial inclination angle β of the blade at the outlet section of the flow channel should be set at 15°-30°, to ensure that the isolation blade can cover the entire chip groove; the cross-sectional thickness of the isolation blade (4) gradually increases from the inlet end to the outlet end, that is, the blade cross section is a variable cross section.

2. The PDC drill bit with a dual flow channel structure according to claim 1, characterized in that: The isolation blade (4) is tempered to increase the hardness of the blade, and diamond or hard alloy particles are embedded in the outer surface of the blade.

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