RU2298077C1 - Crown bit - Google Patents

Abstract

FIELD: rock-cutting tools, particularly drilling bits with diamond cutting structure for well drilling along with core taking.

SUBSTANCE: drilling bit comprises body and matrix separated into sectors with flushing grooves. The sectors are provided with hole-forming, central and core-forming inserts made of superhard alloy and with protective members for hole-forming and core-forming insert protection. The protective members for hole-forming and core-forming inserts are made as bushes with conical apexes and eccentric channels, which are open in outer surface of protective bush. The inserts are arranged in bush interior and are made of wear-resistant material having hardness decreasing from center to periphery thereof.

EFFECT: increased advancing and mechanical drilling speed due to improved protection of inserts against vertical loads acted on drilling bit during bit lowering and due to prevention of tear-outs and ships during rock drilling.

4 cl, 5 dwg

Description

The invention relates to the field of rock cutting tools, namely to drill bits with diamond weapons for drilling wells with coring.

Drill bits are known that include a housing and a matrix divided by flushing grooves into separate sectors reinforced with synthetic diamond inserts (see ed. St. USSR No. 1020565, class E 21 B 10/48, 1983).

The disadvantage of this crown is the rapid wear of the matrix, which leads to the exposure of diamond inserts and, as a consequence of this, to their cleavage and loss to the face.

The closest to the proposed technical essence and the achieved result is a drill bit, comprising a housing and a matrix, divided by flushing grooves into separate sectors, equipped with bore-forming, central and core-forming inserts of superhard material and protective elements for bore-hole and core-forming inserts (see ed. St. USSR No. 625016, class E 21 10/48, 1978).

This crown only partially eliminates the disadvantages of the analogue. This is explained by the presence of a gap between the inserts and the protective elements, as even in the ideal case, cylindrical inserts and protective elements in the form of rods contact each other along a line. Another disadvantage of the analogue and prototype is the likelihood of chips inserts when lowering the crown into the well.

In connection with the stated technical objective of the invention is to increase the efficiency of the crown by increasing the penetration and mechanical drilling speed due to better protection of the inserts from chips and tears.

The stated technical problem is solved in that in the drill bit, comprising a housing and a matrix, divided by flushing grooves into separate sectors, equipped with bore-forming, central and core-forming inserts of superhard material and protective elements for borehole and core-forming inserts, according to the invention, protective elements for borehole and core-forming inserts are made in the form of bushings with an eccentric channel intersecting the outer surface of the bush with the formation of a longitudinal groove oriented calibrating matrix side surface, the insert has channels in eccentric bushings. The solution of the problem also contributes to the fact that:

- protective sleeves are made of wear-resistant material, the hardness of which decreases from the center towards the periphery;

- protective elements are installed in height ahead of the inserts;

- the upper end of the protective sleeve is made in the form of a straight truncated cone.

The invention is illustrated in 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 and figure 3-5 is a view of the protective element, respectively, in the frontal plane, in plan and in perspective view.

The proposed drill bit contains a cylindrical body 1 with a connecting thread 2 and a matrix 3, divided by flushing grooves 4 into separate sectors 5. Each sector is reinforced with bore-forming 6, central 7 and core-forming 8 rock-cutting inserts. The borehole and core-forming inserts 6 and 8 are equipped with protective elements made in the form of bushings 9 with an eccentric channel 10 intersecting the outer surface of the sleeve 9 with the formation of a longitudinal groove 11 oriented toward the gauge surface of the matrix 3, and the inserts 6 and 8 are placed in the eccentric channels 10 bushings 9. The eccentricity ε of the channel 10 is chosen equal to at least the thickness δ of the wall of the sleeve 9, determined by the formula: δ = 0.5 (D-d), where D and d are the outer diameter of the sleeve 9 and the diameter of the channel 10. this protective e the elements 9 of the well-forming inserts 6 are oriented by the grooves 11 towards the outer surface of the matrix 3, and the grooves 11 of the bushings 9 of the core-forming inserts 8 are oriented toward the inner surface of the matrix 3. Due to the eccentric arrangement of the channel 10 and the presence of the groove 11, the outer surface of the well-and core-forming inserts 6 and 8 goes beyond the dimensions of the protective sleeves 9 and is directly involved in the calibration of the walls of the borehole and core, which ensures high penetration to the crown due to the exclusion of "loss" of diameter. Protective elements (bushings) 9 are made of wear-resistant material, the hardness of which decreases from the center of the sleeve 9 along the radius towards the periphery. A predominantly hard alloy is used as a protective material. In a longitudinal section, the upper end of the protective elements 9 is made in the form of a straight cone 12, and the cone 12 is located in height ahead of the rock cutting inserts 6, 7 and 8.

The principle of operation of the crown is as follows. When the drilling tool is lowered together with the crown into the well, a sharp contact of the end face of the crown with the bottom of the well is possible. In this case, brittle inserts 6, 7 and 8 of artificial diamonds will be protected from chipping due to the fact that they are displaced in height relative to the protective elements 9, which absorb the entire load. During the running-in of the crown, alignment of the height of the protective elements and rock-cutting inserts takes place. In order to reduce the exposure time of the inserts 6 and 8, the upper end of the protective elements is made in the form of a straight truncated cone. Under the action of axial load and torque, the rock cutting inserts 6, 7 and 8 together with the protective elements 9 (at the initial moment of the crown operation) produce rock destruction. Moreover, due to the greater wear resistance of the rock cutting inserts 6, 7 and 8 compared with the protective elements 9, the latter wear out faster and thereby expose the inserts from artificial diamonds, which carry out the main work to destroy the face. This also contributes to the fact that the wear resistance of the protective elements 9 decreases from the center of the bushings 9 towards the periphery. Due to this, anticipatory wear of the peripheral part of the protective elements occurs, and the part of them that directly adjoins the inserts 6 and 8 protrudes above the rest of the matrix 3, providing a small contact surface of the protective elements 9 and inserts 6, 7 and 8 with the rock and, as a result of this, significant unit loads. The latter factor is crucial for increasing the mechanical drilling speed. The implementation of the protective elements in the form of bushings 9 protects the inserts 6 and 8 from tearing as a result of wear of the matrix 9 behind the inserts and serves as a support for them, protecting them from loosening and falling out. This factor is crucial for increasing penetration to the crown.

In general, this makes it possible to increase the technical and economic performance of the crowns, namely, the penetration and drilling speed, both by improving the design of the crowns and by protecting the inserts from artificial diamonds from chipping and tearing during the installation of the crown on the bottom of the well and during drilling.

Claims (4)

1. The drill bit, comprising a housing and a matrix, divided by flushing grooves into separate sectors, equipped with bore-forming, central and core-forming inserts of superhard material and protective elements for borehole and core-forming inserts, characterized in that the protective elements for borehole and core-forming inserts are made in the form of bushings with an eccentric channel intersecting the outer surface of the sleeve with the formation of a longitudinal groove oriented towards the gauge surface of the matrix, at m inserts arranged in eccentric bushings channels. 2. The drill bit according to claim 1, characterized in that the protective sleeve is made of wear-resistant material, the hardness of which decreases from the center towards the periphery. 3. The drill bit according to claim 1, characterized in that the protective elements are installed in height ahead of the inserts. 4. The drill bit according to claim 1, characterized in that the upper end face of the protective elements is made in the form of a truncated cone.

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