CN101748974A - A polycrystalline diamond composite sheet for drilling rock-breaking tools - Google Patents

Abstract

The invention discloses a polycrystalline diamond composite sheet used for drilling rock-breaking tools. The composite sheet is a cylinder and includes a polycrystalline diamond layer (1) and a matrix (2) composited therewith. The matrix of the composite sheet It is composed of the remaining part after obliquely cutting by a convex curved surface, and the cut side is composed of the original cylindrical surface (2a) and the new convex curved surface (3), so that the composite sheet body has two ends, large and small, One end with the polycrystalline diamond layer (1) is a big end, and the other end is a small end. Compared with the traditional structure, the present invention reduces the chance of the side of the composite sheet being in contact with the rock (7), and in addition, when the composite sheet wears during the cutting of the rock (7), it can reduce the bearing pressure on the wear surface of the PDC composite sheet The area increases the specific pressure on the rock that interacts with the wear surface of the PDC composite sheet, which is beneficial to enhance the ability of the composite sheet to penetrate into the formation and improve the rock-breaking efficiency of the drill bit.

Description

A polycrystalline diamond composite sheet for drilling rock-breaking tools

technical field

The invention belongs to the technical field of drilling equipment, and relates to a polycrystalline diamond composite sheet used as a rock-breaking tool for drilling.

Background technique

Polycrystalline diamond compact is a cutting element used in drilling tools in drilling engineering, especially polycrystalline diamond compact drill bits (ie PDC drill bits) and other rock breaking tools, referred to as composite chips or PDC teeth for short. As shown in FIG. 8 , the polycrystalline diamond compact is usually a cylinder, and is composed of a polycrystalline diamond layer 5 and a matrix 6 (the matrix material is usually cemented carbide). The outer surface of the base body 6 includes a side surface and a bottom surface, the side surface is usually a cylindrical surface, and the bottom surface is usually a plane. The extremely high hardness of the polycrystalline diamond layer makes it very resistant to wear. At the same time, because the hardness of the polycrystalline diamond layer is much higher than that of the matrix material, the wear rate of the polycrystalline diamond layer is lower than that of the matrix during the cutting of the rock by the composite sheet, so the composite sheet has good wear self-sharpening Function. The outer end surface of the polycrystalline diamond layer is the most important cutting surface on the composite sheet, so it is called the cutting surface or cutting surface of the composite sheet. The intersection line between the working surface and the side of the composite sheet is the contour line of the cutting edge of the composite sheet (when the edge chamfering of the working surface of the composite sheet is ignored, it is the contour line of the outer end surface of the diamond layer).

As shown in FIG. 10 , rock-breaking tools such as PDC bits usually use multiple polycrystalline diamond composite sheets 8 as cutting elements, and each composite sheet 8 is connected to the drill bit body 4 by means of welding or the like. When the drill bit is drilling, multiple composite sheets 8 work simultaneously to realize cutting of the rock 7 by the drill bit.

In the actual drilling process, in addition to the rotary drilling motion of the drill bit, there are usually various complex vibrations, and the shape of the bottom rock 7 is very complicated. Therefore, not only the diamond working plane of each composite sheet will be in contact with the rock 7 , but also the side surfaces of the composite sheet may be in contact with the rock 7 . Usually, the contact between the sides of the PDC teeth and the rock 7 should be avoided as much as possible. Because the contact between the side surface of the PDC tooth and the rock 7 will reduce the effective WOB acting on the working plane of the PDC tooth, thereby weakening the ability of the PDC tooth to eat into the rock 7 .

On the other hand, as shown in Fig. 11, with the continuation of the drilling process of the drill bit, the PDC teeth are constantly worn. The most typical wear mode is to grind out a plane or close to plane area at the contact part of the PDC tooth and the rock 7, which is generally called the wear plane or wear surface of the PDC tooth. With the formation and continuous expansion of the wear surface of the PDC tooth, the area of the wear surface becomes larger and larger, more and more WOB is borne by the wear surface of the PDC tooth, and the effective rock-breaking WOB acting on the PDC tooth becomes more and more The smaller the size, the worse the ability to eat into the formation.

Contents of the invention

The purpose of the present invention is to provide a polycrystalline diamond composite sheet to reduce the possibility of contacting the side of the composite sheet with the rock, and reduce the area of the wear surface of the composite sheet, so as to enhance the ability of the composite sheet to eat into the formation and improve the drill bit. The purpose of rock breaking efficiency.

Technical scheme of the present invention is as follows:

A polycrystalline diamond composite sheet used for drilling rock-breaking tools, the composite sheet is a cylinder, including a polycrystalline diamond layer and a matrix composited with it, and the matrix of the composite sheet is obliquely cut by a convex curved surface The remaining part is composed of the side after cutting, which is composed of the original cylindrical surface and the new convex surface, so that the composite sheet body has two ends, one end with the polycrystalline diamond layer is the big end, and the other end is the small end. head end.

As shown in Figure 9-1 and 9-2, with the above structure, compared with the traditional cylindrical composite sheet, the wear surface area obtained at the same wear height is smaller than that of the conventional composite sheet. Under changing conditions, the contact surface between the PDC tooth and the rock becomes smaller, the pressure becomes larger, and the eating ability is significantly enhanced. At the same time, after a part of the matrix of the composite sheet is obliquely cut off by a convex curved surface, the distance between the points on the side of the matrix and the rock increases, reducing the chance of contact between the side of the composite sheet and the rock, which is conducive to increasing the effective WOB , improve the rock-breaking efficiency of the drill bit.

The convex curved surface is a conical surface.

The convex curved surface is a cylinder.

The bottom surface of the base body is in the shape of a crescent.

Beneficial effects: Compared with the traditional structure, the present invention reduces the chance of the side of the composite sheet being in contact with the rock 7. In addition, when the composite sheet is worn during the process of cutting the rock 7, the bearing area of the wear surface of the PDC composite sheet can be reduced , increase the specific pressure on the rock that interacts with the wear surface of the PDC composite sheet, which is beneficial to enhance the ability of the composite sheet to penetrate into the formation and improve the rock-breaking efficiency of the drill bit.

Description of drawings

The invention will be illustrated by way of example with reference to the accompanying drawings, in which:

Fig. 1 is the perspective view that the convex curved surface of the present invention is a conical surface;

Fig. 2 is the front view of Fig. 1;

Fig. 3 is the top view of Fig. 1;

Fig. 4 is the right view of Fig. 1;

Fig. 5 is the front view that the convex curved surface of the present invention is a cylindrical surface;

Figure 6 is a top view of Figure 5;

Fig. 7 is the right view of Fig. 5;

Fig. 8 is a schematic structural view of the original polycrystalline diamond composite sheet in the background technology;

Figures 9-1 and 9-2 are comparison diagrams of the wear surfaces before and after improvement;

Fig. 10 is a schematic structural view of the present invention installed on the drill body;

Figure 11 is a diagram of the use state of the present invention;

Detailed ways

Embodiment: as shown in Figures 1, 2, 3, 4, 5, 6, and 7: a polycrystalline diamond composite sheet for drilling and rock-breaking tools, the composite sheet is a cylinder, including a polycrystalline diamond layer 1 and Composite with it matrix 2, the matrix of this composite sheet is formed by the remaining part after oblique cutting of a convex curved surface, and the side after cutting is composed of the original cylindrical surface 2a and the new convex curved surface 3, so that all The body of the composite sheet has a large and a small end, wherein one end with the polycrystalline diamond layer 1 is a large end, and the other end is a small end. The convex curved surface 3 is a conical surface or a cylindrical surface. The bottom surface of the base body 2 is in the shape of a crescent.

The key of the present invention is to cut off a piece on the original cylindrical base, so that the side of the base has an inclined convex curved surface. As can be seen from the perspective view Fig. 1, it is guaranteed that the inclined direction of the inclined convex curved surface is from the left Slope to the right and down, that is, the cut composite sheet has a polycrystalline diamond layer 1 with a large end at one end and a small end at the other end. At the same time, the bottom surface of the substrate 2 obtained after cutting in this oblique direction must be in the shape of a crescent (as shown in FIG. 4 or 7 ). In order to meet the shape requirement, besides the above-mentioned conical surface or cylindrical surface, other kinds of curved surface forms can also be selected for the convex curved surface, such as a compound curved surface composed of a conical surface and a cylindrical surface.

Claims (4)

1. A polycrystalline diamond composite sheet for drilling and rock-breaking tools, the composite sheet is a cylinder, comprising a polycrystalline diamond layer (1) and a matrix (2) composited therewith, characterized in that: the composite sheet The matrix is formed by the remaining part after oblique cutting of a convex curved surface, and the side after cutting is composed of the original cylindrical surface (2a) and the new convex curved surface (3), so that the composite sheet body has two ends, large and small. end, wherein one end with the polycrystalline diamond layer (1) is a large end, and the other end is a small end. 2. A polycrystalline diamond compact for drilling and rock-breaking tools according to claim 1, characterized in that: the convex curved surface (3) is a conical surface. 3. A polycrystalline diamond compact for drilling and rock-breaking tools according to claim 1, characterized in that: the convex curved surface (3) is a cylindrical surface. 4. A polycrystalline diamond composite sheet for drilling and rock-breaking tools according to claim 1, 2, 3, characterized in that: the bottom surface of the base (2) is in the shape of a crescent.

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