PDC (Polycrystalline Diamond Compact) drill bit cutting tooth and tooth arrangement method

Abstract

The invention discloses a PDC drill bit cutting tooth and a tooth arranging method, the cutting tooth is arranged on a blade of a PDC drill bit, the cutting tooth is provided with a base and a superhard layer located at the top end of the base, the top surface of the superhard layer is a cutting surface, the cutting tooth is installed on the blade according to the angle direction that the cutting surface of the cutting tooth forms an alpha angle relative to the plane of a stratum to be broken, and the tooth arranging method is characterized in that the cutting surface of the cutting tooth is arranged on the blade; and the angle alpha is greater than 90 degrees. By adjusting the tooth distribution position and angle, the working faces of the cutting teeth form obtuse angles with the plane of the well bottom, and the working faces of the cutting teeth are inclined upwards, so that the working states of the cutting teeth are changed, the stress states of rocks to be crushed and the cutting teeth are changed, and original shear crushing is changed into tensile shear crushing; the input work required by the cutting teeth for crushing isovolumetric rocks is reduced, and meanwhile, the drill bit is kept stable at the bottom of the well, so that the aim of increasing the drilling speed is fulfilled.

Description

Technical Field

[0001] The invention relates to a drill bit used in oil exploration and drilling operations in the oil and gas industry, and in particular to a PDC drill bit cutting tooth and a tooth arrangement method. Background Art

[0002] Polycrystalline diamond cutting tooth alloy drill bits (PDC drill bits for short) are commonly used in oil and gas drilling. PDC drill bits consist of drill bit body, blades and cutting teeth. Figure 1 The typical PDC drill bit cutting tooth structure is cylindrical in shape and has a cutting tooth axis. The cylinder is divided into a bottom part and a top part. The bottom part of the cylinder, i.e., the base 2, is usually made of a hard composite material such as tungsten carbide, while the top part, also known as the superhard layer 3, is usually made of a hard wear-resistant material such as polycrystalline diamond (PCD).

[0003] For a typical cutting tooth, the top surface of the superhard layer 3 (also called the cutting surface) is flat and parallel to the bottom surface of the substrate, that is, perpendicular to the cutting tooth axis. The height of any point on the cutting surface relative to the bottom surface of the substrate is equal to the height of the cutting tooth, that is, the thickness of the superhard layer 3 is basically uniform, and the cutting surface angle between the cutting surface and the cutting tooth axis is 90 degrees. However, when the cutting teeth of this traditional structure are working, the drill bit often slips, jumps up, and jumps the drill. The drill bit has poor self-stability, which puts the cutting teeth in an unstable working state at the bottom of the well, accelerates the damage of the cutting teeth of the drill bit, thereby reducing the drilling speed and affecting the drilling efficiency.

[0004] Therefore, the researchers have conducted a lot of research and development and improvements on the cutting structure and cutting teeth of the PDC drill bit. For example, the patent document CN218862539U, a PDC drill bit with composite teeth, discloses that the cutting teeth are bevel teeth, and the plane of the polycrystalline diamond composite sheet on the top surface of the cutting teeth maintains an acute angle of 55 to 85 degrees with the drilling surface as the feed angle when the drill bit is drilling, thereby improving the cutting tooth structure. The patent document CN213330909U, a polycrystalline diamond composite sheet with a conical substrate, discloses that the cemented carbide substrate can be a linear cone, a curved cone, and a stepped cone; the shape of the base is improved. However, the effects of the above improvements are not obvious in practical applications, especially in hard plastic formations. Summary of the invention

[0005] In view of this, the purpose of the present invention is to provide a PDC drill bit cutting tooth. By designing the structure and installation position of the cutting tooth, the working angle of the cutting surface of the cutting tooth is changed, so that the working surface of the cutting tooth tends to be inclined upward, thereby changing the working state of the cutting tooth to solve the technical problems that are difficult to overcome in the above-mentioned prior art, such as drill bit slippage, drill jumping, and poor self-stability, which affect the life of the drill bit.

[0006] Another object of the present invention is to provide a PDC drill bit tooth arrangement method, in which the cutting teeth are installed on the PDC drill bit blade by adjusting the tooth arrangement position and angle, and the blade is reasonably arranged to solve the technical problems in the prior art.

[0007] Specifically, the present invention achieves the above-mentioned invention object through the following technical solutions:

[0008] The present invention relates to a PDC drill bit cutting tooth, which is arranged on the blade of the PDC drill bit. The cutting tooth has a base and a superhard layer located at the top of the base, and the top surface of the superhard layer is a cutting surface. When cutting, the cutting tooth performs cutting work according to the angle α between its cutting surface and the plane of the formation to be broken, and the angle α is greater than 90 degrees. Further, the cutting tooth is installed on the blade in an orientation that the cutting surface is α with the plane of the formation to be broken, and the cutting surface is rotated clockwise or counterclockwise along the central axis of the cutting tooth by a certain angle θ. In some embodiments, the angle θ is 15° to 30°; preferably, the angle θ is 20° to 25°.

[0009] In some embodiments, the PDC drill bit cutting teeth, the superhard layer is an unequal thickness beveled cylinder, the thinnest thickness of the unequal thickness beveled cylinder is not less than 1.2 mm. Further, the thinnest thickness of the unequal thickness beveled cylinder is 1.2-2.4 mm. The top of the unequal thickness beveled cylinder is a bevel, the inclination angle of the bevel relative to the bottom surface of the base is β, and the β is 5° to 30°; preferably, the β is 10° to 20°; further preferably, the β is 10°; the bevel is a cutting surface, the bevel has an inclined low end and an inclined high end, and the inclined high end acts as a main cutting edge on the formation to be broken.

[0010] The present invention also relates to a PDC drill bit tooth arrangement method, using the above-mentioned PDC drill bit cutting teeth, comprising the following steps: S1 at least four blades are arranged on the PDC drill bit, each blade has at least one installation position for the cutting teeth; S2 the cutting teeth are installed in the installation position in an angle orientation of their cutting faces with respect to the plane of the formation to be broken, and the angle α is greater than 90 degrees. Preferably, the cutting teeth are installed in the installation position in an orientation in which their cutting faces form an angle α with respect to the plane of the formation to be broken, and the cutting faces are rotated clockwise or counterclockwise along the central axis of the cutting teeth by a certain angle θ. Preferably, the cutting faces of the cutting teeth on the same blade have the same rotation direction and angle θ.

[0011] Preferably, the number of blades is an even number, and the cutting surfaces of the cutting teeth on at least two blades rotate in different directions from the cutting surfaces of the cutting teeth on the other blades; the blades are symmetrically arranged on the PDC drill bit, and the cutting surfaces of the cutting teeth on the symmetrical blades rotate in the same direction.

[0012] By adopting the above technical solution, the technical effects of the present invention are mainly reflected in the following aspects:

[0013] (1) The present invention adjusts the tooth arrangement position and angle so that the working surface of the cutting teeth forms a right angle or an obtuse angle with the formation plane (or the bottom plane of the well), and the cutting surface of the cutting teeth (i.e., the working surface) is inclined to face obliquely upward, thereby changing the working state of the cutting teeth and the stress state of the rock to be crushed and the cutting teeth, changing the original shear crushing into tensile shear crushing, reducing the input work required for the cutting teeth to crush the same volume of rock, and keeping the drill bit stable at the bottom of the well, thereby achieving the purpose of increasing the drilling speed.

[0014] (2) The cutting teeth of the present invention are not affected by the shape of the drill bit and can be applied to any type of PDC drill bit;

[0015] (3) The present invention takes advantage of the fact that the rock has the lowest tensile strength and can crush the same volume of rock with a smaller input work, thus effectively improving the drilling efficiency.

[0016] (4) The cutting teeth and tooth arrangement method of the present invention are applicable to a wide range of formations, especially in hard plastic formations, and the drill bit can crush rocks more stably; it is suitable for PDC drill bits for drilling oil and gas, hydrogeology, coal, etc. to improve the drilling speed and stability of the drill bit, thereby improving the overall drilling efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the structure and working state of the drill bit cutting teeth in the prior art;

[0018] Figure 2 A front view of a PDC drill bit cutting tooth according to an embodiment of the present invention;

[0019] Figure 3 for Figure 2 Side view of the PDC drill bit cutting teeth;

[0020] Figure 4 for Figure 2 Schematic diagram of the layout method of PDC drill bit cutting teeth Figure 1 ;

[0021] Figure 5 for Figure 2 Schematic diagram of the layout method of PDC drill bit cutting teeth Figure 2 ;

[0022] Figure 6 for Figure 2 Schematic diagram of the layout method of PDC drill bit cutting teeth Figure 3 ;

[0023] Wherein: 1-blade wing, 2-base, 3-superhard layer, 4-plane of formation to be broken, 5-formation to be broken, 6-cutting surface, 61-inclined lower end, 62-inclined high end, 7-PDC drill bit, α-angle between cutting surface and plane of formation to be broken, β-inclination angle of cutting surface relative to bottom surface of base, θ-angle of cutting surface rotating in clockwise or counterclockwise direction along the center axis of cutting tooth. DETAILED DESCRIPTION

[0024] The specific implementation methods of the present invention are further described in detail below in conjunction with the accompanying drawings to make the technical solution of the present invention easier to understand and grasp. In this embodiment, it should be understood that the terms "middle", "upper", "lower", "top", "right", "left end", "above", "back", "middle", etc. indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the present invention, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0025] During the drilling process, the PDC drill bit is placed at the bottom of the wellbore and rotates to cut the inner surface of the wellbore. The cutting teeth on the blade are installed on the blade at an angle α to the plane 4 of the formation to be broken, which is predetermined by the cutting surface. As the drill bit rotates, the PDC cutting teeth cut and shear the rock formation. Figure 1 The state of the cutting surface of a conventional cutting tooth in the prior art when cutting the formation 5 to be broken (rock to be broken) is shown. It is found through research that the cutting surface of the cutting tooth always maintains a certain angle α with the plane 4 of the formation to be broken, and the angle α is usually an acute angle. During the drilling process, when the cutting tooth is working, its cutting surface, i.e., the working surface, performs rock breaking and drilling by shearing. However, since the cutting surface is at an acute angle with the formation plane 4 (bottom of the well), the cutting surface exerts a downward pressure on the rock to be broken during operation, and the corresponding rock exerts an upward reaction force on the cutting tooth. The downward pressure exerted by the cutting tooth on the rock to be broken increases the shear strength of the rock, which is not conducive to the rapid rock breaking of the cutting tooth. At the same time, the upward reaction force exerted by the formation 5 to be broken (rock to be broken) on the working surface of the cutting tooth causes the drill bit to slip and jump, resulting in drill jumping. The drill bit has poor self-stability, which makes the cutting tooth in an unstable working state at the bottom of the well, accelerates the damage of the cutting tooth of the drill bit, and thus reduces the drilling speed.

[0026] The embodiment of the present invention provides a PDC drill bit cutting tooth, such as Figure 2 and 3As shown, the cutting tooth has a base 2 and a superhard layer 3 located at the top of the base 2. The superhard layer 3 is a PDC composite sheet of an unequal thickness beveled cylinder, and the base 2 is a cemented carbide column. The beveled cylindrical PDC composite sheet is connected to the cemented carbide column through a special sintering process (for those skilled in the art, it is common knowledge and can be achieved without any creative labor, so it will not be described separately) to form an integral beveled cylindrical cutting tooth. The thinnest thickness of the unequal thickness beveled cylindrical PDC composite sheet is not less than 1.2mm. Furthermore, the thinnest thickness of the unequal thickness beveled cylinder is 1.2-2.4mm. The top of the unequal thickness beveled cylinder is a cutting surface 6, and the inclination angle of the cutting surface 6 relative to the bottom surface of the base 2 is β, and β is 5° to 30°; preferably, β is 10° to 20°; more preferably, β is 10°. The cutting surface 6 has an inclined low end 61 and an inclined high end 62, and the inclined high end 62 acts as a main cutting edge on the formation 5 to be broken.

[0027] Another embodiment of the present invention provides a PDC drill bit cutting tooth, which adopts the cutting tooth structure of the above embodiment, and the cutting tooth is installed on the blade 1 with its cutting surface 6 at an angle α relative to the plane 4 of the formation to be broken, and the angle α is greater than 90 degrees. The working surface of the cutting tooth forms an obtuse angle with the bottom plane of the well, which changes the stress state of the rock to be broken and the cutting tooth, directly performs rapid shearing and crushing, reduces the input work required for the cutting tooth to crush the same volume of rock, and maintains the longitudinal and lateral stability of the drill bit at the bottom of the well.

[0028] Another embodiment of the present invention provides a PDC drill bit cutting tooth, which adopts the cutting tooth structure of the above embodiment, wherein the cutting tooth has a cutting surface 6 that forms an angle α with the plane of the formation to be broken, and the cutting surface 6 is installed on the blade 1 at a certain angle θ rotated clockwise or counterclockwise along the center axis of the cutting tooth. The angle θ is 15° to 30°; preferably, the angle θ is 20° to 25°. This embodiment not only ensures that the working surface of the cutting tooth forms an obtuse angle with the plane of the bottom of the well, but also ensures that the cutting surface 6 is inclined upward and tilted at a certain angle in the radial direction of the wellbore, thereby changing the stress state of the rock to be broken and the cutting tooth, changing the original shear crushing to tensile shear crushing, reducing the input work required for the cutting tooth to crush an equal volume of rock, and at the same time maintaining the longitudinal and lateral stability of the drill bit at the bottom of the well, extending the service life of the drill bit, thereby achieving the purpose of increasing the drilling speed.

[0029] Another embodiment of the present invention provides a PDC drill bit cutting tooth arrangement method, such as Figure 4-6 As shown, the following steps are included:

[0030] S1: Six blades 1 are arranged on the PDC drill bit 7, and each blade 1 has at least one mounting position for a cutting tooth;

[0031] S2: The cutting tooth is installed in the installation position at an angle α with respect to the plane of the formation to be broken by its cutting face 6, wherein the angle α is an obtuse angle; preferably, the cutting tooth is installed in the installation position of the blade 1 at an angle α with respect to the plane 4 of the formation to be broken by its cutting face 6, and the cutting face 6 is rotated by a certain angle θ in a clockwise or counterclockwise direction along the central axis of the cutting tooth. Preferably, the cutting faces 6 of the cutting teeth on the same blade wing 1 have the same rotation direction and angle θ.

[0032] The number of S3 blades 1 is an even number, and the cutting surfaces 6 of the cutting teeth on at least two blades 1 have a different rotation direction from the cutting surfaces 6 of the cutting teeth on other blades 1; the blades 1 are symmetrically arranged on the PDC drill bit 7, and the cutting surfaces 6 of the cutting teeth on the symmetrical blades 1 have the same rotation direction.

[0033] During tooth arrangement and installation, the beveled cylindrical cutting teeth are installed on the blade 1 of the PDC drill bit 7 by means of an inlay process (this is common knowledge to those skilled in the art and can be achieved without any creative labor, so it will not be described separately). The relative position of the cutting teeth and the blade 1 is adjusted so that the cutting surface (working surface) 6 of the cutting teeth maintains an obtuse angle α with the plane of the formation to be broken (rock surface at the bottom of the well) 4. At the same time, the beveled cylindrical cutting teeth are rotated clockwise or counterclockwise by an angle θ. At this time, the cutting surface 6 of the cutting teeth tends to face obliquely upward, thereby applying an obliquely upward force component to the formation to be broken (rock to be broken) 5, so that the formation to be broken 5 is subjected to forces in both shear and tensile directions at the same time. Since the tensile failure strength of the formation to be broken is the smallest, under the action of the tensile force, the formation to be broken 5 is easier to break than being subjected to shear force only. At the same time, the formation to be broken 5 gives a reaction force obliquely downward to the working surface of the cutting teeth. This reaction force makes the PDC drill bit 7 close to the bottom of the well and limits its lateral movement, ensuring stable cutting of the PDC drill bit 7, thereby achieving the purpose of the present invention.

[0034] Of course, the above are only typical examples of the present invention. In addition, the present invention can also have many other specific implementations. All technical solutions formed by equivalent replacement or equivalent transformation fall within the scope of protection required by the present invention.

Claims

1. A PDC drill bit cutting tooth, arranged on a blade of the PDC drill bit, the cutting tooth having a base and a superhard layer located on the top of the base, the top surface of the superhard layer being a cutting surface, characterized in that: During cutting, the cutting teeth perform cutting work with their cutting faces forming an angle α relative to the plane of the formation to be broken, and the angle α is greater than 90 degrees.

2. The PDC drill bit cutting tooth according to claim 1, characterized in that: The cutting teeth are installed on the blades at an angle α between their cutting faces and the plane of the formation to be broken, and the cutting faces are rotated along the central axis of the cutting teeth by a certain angle θ in a clockwise or counterclockwise direction.

3. The PDC drill bit cutting tooth according to claim 2, characterized in that: The angle θ is 15° to 30°.

4. The PDC drill bit cutting tooth according to claim 1, characterized in that: The superhard layer is an unequal thickness inclined plane cylinder, the top of which is an inclined plane, which is a cutting plane, and has an inclined low end and an inclined high end, which acts as a main cutting edge on the stratum to be broken.

5. The PDC drill bit cutting tooth according to claim 4, characterized in that: The thinnest thickness of the unequal thickness inclined cylinder is not less than 1.2 mm.

6. The PDC drill bit cutting tooth according to claim 4, characterized in that: The inclination angle of the inclined surface relative to the bottom surface of the base is β, and the β is 5° to 30°.

7. A PDC drill bit tooth arrangement method, characterized in that: Using the PDC drill bit cutting teeth as described in any one of claims 1 to 6, comprising the following steps: S1. At least four blades are arranged on the PDC drill bit, and each blade has at least one mounting position for a cutting tooth; S2. Install the cutting teeth in the installation position with their cutting faces forming an angle α relative to the plane of the formation to be broken, wherein the angle α is greater than 90 degrees.

8. The PDC drill bit tooth arrangement method according to claim 7, characterized in that: In step S2, the cutting tooth is installed in the installation position in a direction in which the cutting surface forms an angle α with the plane of the formation to be broken, and the cutting surface is rotated clockwise or counterclockwise along the center axis of the cutting tooth by a certain angle θ.

9. The PDC drill bit tooth arrangement method according to claim 8, characterized in that: In step S2, the cutting faces of the cutting teeth on the same blade have the same rotation direction and angle θ.

10. The PDC drill bit tooth arrangement structure according to claim 8, characterized in that: The number of blades is an even number, and the cutting surfaces of the cutting teeth on at least two blades rotate in a different direction from the cutting surfaces of the cutting teeth on the other blades; The blades are symmetrically arranged on the PDC drill bit, and the cutting faces of the cutting teeth on the symmetrical blades have the same rotation direction.

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