RU2517656C2 - Rock drill bit tooth for drilling of impermeable rocks - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to rock crushing equipment, particularly, to rock drill bit teeth. Drill bit bucket-shape tooth comprises flow grooves at rear side extending to tooth working edges. Said grooves make fluid channels between tooth rear side and face non-destructed rock to communicate rock destruction zone with bore hole.

EFFECT: higher efficiency of impermeable rock crushing owing to equalising hydrostatic pressure ahead of the tooth.

5 dwg

Description

The invention relates to weapons of rock cutting tools used in well drilling, namely to the teeth of cone bits.

Known cone bit, including roller cutters with weapons, made in the form of wedge-shaped teeth with a blunted working edge. Such a tooth is intended for deep penetration into soft and medium hardness rocks [1] (analogue). The teeth under consideration are mounted in the crowns of the chisel bits.

The design of the bit provides for slipping along the face of the rims of the main weapon, in contrast to the peripheral one, which enhances the destructive ability of the bit. The freer introduction of the main armament into the breed to some extent is hindered by the flat profile of the incident face of the tooth.

Partially, this drawback is eliminated in the teeth, in which the incident face is made with a radial selection. These are the so-called bucket-shaped teeth. The shape of the tooth improves the rise of cuttings of cuttings from the holes [2] (prototype). Such teeth do not simply shift the rock when they are introduced into the massif, but form a fracture in the rock in front of the working edge of the teeth and tear the rock from the bottom.

The disadvantage of the bucket-shaped tooth in this case is that when drilling impermeable rocks, the hydrostatic pressure of the borehole is substantially opposed to the opening of the cracks and the rock fragments separated from the bottom are poorly removed.

The aim of the invention is to increase the efficiency of the destruction of impermeable rocks by equalizing the hydrostatic pressure in the fracture zone of the rock in front of the tooth.

This goal is achieved by the fact that on the back side of the tooth contains flowing grooves extending to the working edges of the tooth, which, when the bit is operated, form hydraulic channels between the back side of the tooth and the rock not affected by rock destruction, connecting the rock destruction zone to the well cavity.

Figure 1 presents the bucket-shaped tooth with a flowing groove on its back side. Figure 2 - clove with a flowing groove on the back side in section. Figure 3 shows a bucket-shaped tooth of a larger diameter with two grooves, for example, mounted in bits for drilling in soft rocks or bits of large sizes. In Fig. 4, the claimed tooth is in contact with the rock at the beginning of the act of introducing and forming the crack A, when hydrostatic pressure prevents the crack faces from opening. In Fig. 5, the tooth is at the end of the introduction act, when the hydrostatic pressure is aligned in the crack B through the hydraulic channel formed by the unaffected destruction by the face array and the groove on the back of the tooth.

The mechanism of rock destruction occurs as follows. Due to the fact that the tooth on the back side contains flowing grooves extending to the working edges of the tooth, which during operation of the bit form hydraulic channels between the back side of the tooth and the rock not affected by rock destruction, connecting the rock destruction zone to the well cavity, the hydrostatic pressure is equalized in the fracture zone impermeable rock in front of the tooth. At the beginning of the interaction of the tooth with the rock, it is introduced with a shift, which is accompanied by the formation of a crack A in Fig. 4 in front of the working edge of the tooth, where a vacuum is created due to the impossibility of penetrating into this region of the flushing fluid located in the well. Hydrostatic pressure prevents crack opening. These two circumstances contribute to filling the crack A in Fig. 4 through the hydraulic channel from an unaffected by the destruction of the face array and the grooves on the back of the tooth, equalizing the pressure between the cavity of the crack and the well. Further introduction of the claimed clove easily pushes the edges of the crack B in FIG. 5, replenishing the increasing volume of the crack through the same hydraulic channel with flushing fluid. The groove, coupled with unaffected destruction by the face array, serves as a reliable hydraulic channel between the well and the fracture, since the surface of the face rock is formed (smoothed) by a part of the working edge of the tooth.

As part of an undeclared decision, it should be noted that peripheral armaments in the form of a wedge-shaped or spherical clove, in which slip is not provided, must be performed with a groove on the working edge of the clove or a spherical recess for forced expansion of the fracture by the borehole fluid.

Information sources

1. Roller bits and drill bits. Catalog. - Ed. TSINTIHIMNEFTEMASH, M., 1990 .-- 93 p. (see pages 25, 27 and 28).

2. Maslennikov I.K. Drilling tool. Directory. - M .: Nedra, 1989 .-- 430 p. (see page 84 fig. 2.1.32, c, h, and).

Claims (1)

A bucket-shaped chisel tooth, characterized in that in order to increase the destruction efficiency of impermeable rocks by equalizing the hydrostatic pressure in the rock fracture zone in front of the tooth, the tooth contains flow grooves on the back that extend to the working edges of the tooth, which form hydraulic channels between the back of the tooth and the rock not affected by the destruction of the face, connecting the zone of destruction of the rock with the cavity of the well.

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