RU2489563C1 - Crown bit - Google Patents

Abstract

FIELD: mining.

SUBSTANCE: crown bit comprises a crown ring, the end of which is divided by washing slots into sectors, reinforced with well and core forming cutters. The feature of the crown bit is the fact that well and core forming cutters are made in plan as rectangular trapezoids, the smaller bases of which are turned towards rotation of the crown. At the same time their inclined sides facing each other are made as concave or in the form of a straight line and are displaced in the radial direction one from another. At the same time side faces of well and core forming cutters in plan are serrated.

EFFECT: increased efficiency of crown bit operation.

4 cl, 5 dwg

Description

The invention relates to a rock cutting tool, namely to crowns intended for drilling wells with coring.

A drill bit is known that includes a body with rock cutting inserts consisting of a support plate, core, core and borehole cutters with a stepwise arrangement and with a shift of the core and core and borehole cutters in the radial plane (see ed. St. USSR No. 530941, class E21B 10/02, 1976).

The disadvantages of this crown include the difficulty of mounting the inserts in the housings, which inevitably reduces the quality of the products and reduces their technical and economic indicators.

The closest to the proposed technical essence and the achieved result is a drill bit containing a core ring, the end of which is divided by flushing grooves into sectors reinforced with borehole and core forming tools (see Kornilov N.I. et al. Rock-cutting tool for exploration wells. M Subsoil, 1079 g, p. 163, Fig. 11.14).

The disadvantage of this crown is the low efficiency in operation associated with the high energy intensity of the process of destruction of the rock and, as a consequence, to increased wear of the cutters and the failure of the crown.

In connection with the stated technical result of the invention is to increase the efficiency of the crown by creating additional outcrop planes.

The specified technical result is achieved by the fact that in the drill bit containing the crown ring, the end of which is divided by flushing grooves into sectors reinforced with borehole and core forming cutters, according to the invention, the borehole and core forming cutters are made in plan in the form of rectangular trapeziums, the smaller bases of which are turned into the side of rotation of the crown, and their inclined lateral sides facing one another, are made concave or in the form of a straight line and are displaced in the radial direction from one another, while s hand and skvazhino- kernoobrazuyuschih incisors plan have a sawtooth shape.

The solution of the problem also contributes to the fact that:

- the tops of the sawtooth protrusions on the side faces of the borehole and core-forming incisors for soft and medium rocks are directed in the direction of rotation of the crown, and for harder rocks in the opposite direction;

- the front face relative to the direction of rotation of the crown of the borehole - and core-forming incisors has a sawtooth plan with symmetrically located side faces;

- that the vertices of the sawtooth protrusions on opposite lateral faces of the borehole and core-forming cutters in the plan are shifted one relative to the other in the circumferential direction.

The invention is illustrated by the drawing, in which figure 1 depicts a General view of the crown, figure 2 is a view of the crown from the side of the working end; figure 3 - two options for performing carbide cutters in plan on an enlarged scale; in Fig.4 - nodes 1 and 11 in Fig.3 on an enlarged scale and in Fig.5 - node 111 in Fig.3 on an enlarged scale.

The drill bit includes a core ring 1 with a connecting thread 2, flushing grooves 3, dividing the crown end into sectors 5, reinforced with borehole and core forming cutters 6 and 7. Cutters 6 and 7 have a plan view of rectangular trapezoid with bases 9 and 10, smaller bases 9 of which are turned in the direction of rotation of the crown. Their inclined sides facing one another are made of a concave shape 8 (the left part in FIG. 3) or in the form of a straight line 4 (the right part in FIG. 3) and are radially offset from one another. In this case, the lateral faces of the borehole and core forming cutters 6 and 7 in the plan have a sawtooth shape. Moreover, the vertices 11 and 12 of the sawtooth protrusions on the lateral faces of the borehole and core forming cutters 6 and 7 for soft and medium rocks are directed in the direction of rotation of the crown (left side in figure 4), and for harder rocks - in the opposite direction (right side on figure 4). In this case, the vertices 11 and 12 of the sawtooth protrusions are shifted in plan in the circumferential direction on the inner and outer side walls of the trapezoid by an amount of -h, which reduces the likelihood of cleavage of carbide cutters 6 and 7 due to the exclusion of stress concentrators in the body of the cutters. The front face (relative to the direction of rotation of the crown) (the smaller base of the trapezoid 9) of the borehole and core forming cutters 6 and 7 also has a sawtooth shape with symmetrically located side faces 13 (see Fig. 5).

The principle of operation of the crown is as follows. Under the action of axial load and torque, borehole and core-forming cutters 6 and 7 penetrate into the rock and destroy it. The destroyed rock is carried out from the bottom to the surface by flushing fluid pumped through the drill string and core ring 1. During the drilling process, an annular protrusion is formed between the borehole and core forming cutters 6 and 7, which centers the crown and thereby reduces its radial runout and vibration . Moreover, to increase the efficiency of calibration of the walls of the borehole and the destruction of the annular protrusion of the rock under the end face of the crown ring 1, the front and side walls of the cutters 6 and 7 are made in a sawtooth plan. Moreover, the tops of the teeth 11 and 12 on the lateral sides of the incisors are directed in the direction of rotation of the crown - for soft and medium rocks and in the opposite direction - when drilling harder rocks. The teeth on the front face of the cutters 6 and 7 are made with symmetrically located side faces 13.

This performance of the crown helps to increase the efficiency of its work by reducing the energy intensity of the process of rock destruction, which in turn is achieved by creating additional outcrop planes.

Claims (4)

1. A drill bit containing a crown ring, the end of which is divided by flushing grooves into sectors reinforced with borehole and core forming cutters, characterized in that the borehole and core forming cutters are made in plan in the form of rectangular trapezoid, the smaller bases of which are turned in the direction of rotation of the crown, and their inclined lateral sides facing one another, are made concave or in the form of a straight line and are shifted in the radial direction from one another, while the side faces of the borehole and core forming cutters in plan and eyut sawtooth shape. 2. The drill bit according to claim 1, characterized in that the vertices of the sawtooth protrusions on the lateral faces of the borehole and core forming cutters for soft and medium rocks are shifted in the direction of rotation of the crown, and for harder rocks in the opposite direction. 3. The drill bit according to claim 1, characterized in that the front relative to the direction of rotation of the crown, the face of the borehole and core forming cutters has a sawtooth plan with symmetrically located side faces. 4. The drill bit according to claim 1, characterized in that the vertices of the sawtooth protrusions on the opposite side faces of the cutters in the plan are offset one relative to the other in the circumferential direction.

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