RU2493351C2 - Diamond pilot drill bit - Google Patents

Abstract

FIELD: mining.

SUBSTANCE: diamond pilot drill bit comprises a diamond-containing matrix with a pilot, separated by end, internal and external side, inclined and additional cylindrical washing channels into sectors and a body with an external circular bore. Additional cylindrical washing channels reaching into end washing channels are arranged perpendicularly to the working end of the bit and displaced along the radius to the periphery of the matrix pilot, and the diameter of the additional cylindrical channel is determined in accordance with the established dependence, at the same time the total area of transverse sections of inner side washing channels of the bit is found from the rated ratio. Besides, inlet edges of additional cylindrical channels are made as conical with a sharp angle at the top of the cone, and the inclined washing channels are arranged with alternating capacity, which increases towards the external circular bore of the bit body.

EFFECT: increased mechanical speed of drilling, bit resistance, increased core integrity.

2 dwg

Description

The invention relates to drilling equipment and, in particular, to drill bits reinforced with natural and artificial diamonds for drilling deep wells, including with the use of shells with removable core receivers in conditions of difficulty in obtaining a conditional core output.

Known diamond drill bit, comprising a housing and a diamond-containing matrix with additional cylindrical and side and inclined flushing channels, characterized in that the additional cylindrical channels are radially offset to the center of the pilot (see US Patent No. 3026952, 175-330).

The disadvantage of this crown are:

- irrational layout of the outputs of the longitudinal cylindrical channels on the end of the matrix, as a result of which the core is exposed to side flows of the washing fluid and is destroyed;

- not the optimal diameter of the additional cylindrical channel, which does not ensure the formation of the hydro-monitor effect of the jet;

- the implementation of inclined flushing channels with a constant capacity;

- the presence of sharp input edges in additional cylindrical channels.

These disadvantages cause the use of such a crown low mechanical drilling speed and durability and a decrease in core safety.

The closest in technical essence and the achieved result to the proposed one is a diamond stepped drill bit, including a diamond-containing matrix with a pilot, divided by end, inner and outer side, inclined and additional cylindrical flushing channels into sectors and a body with an outer ring groove (see. Description of the utility model “Diamond step crown. Certificate for utility model No. 10767 of 08.16.1999, Russia).

The disadvantage of this crown are:

- irrational layout of the outputs of the additional cylindrical channels of the matrix and the non-optimal diameter of these cylindrical channels, as well as not a rational ratio of the cross-sectional areas of the internal side washing channels and additional cylindrical washing channels.

The proposed technical solution is directed:

- to increase the mechanical drilling speed and crown resistance due to the rational layout of the outputs of the longitudinal cylindrical flushing channels and the optimal design of these channels, as well as the inclined flushing channels and increasing the core safety by preventing erosion of the side flow of flushing fluid on the core due to the rational choice the ratio of the cross-sectional areas of the internal side washing channels and additional cylindrical washing ka als.

The problem is solved in that in a diamond stepped drill bit, including a diamond-containing matrix with a pilot, divided by end, inner and outer side, inclined and additional cylindrical flushing channels extending into the end flushing channels, into sectors and a body with an external annular groove, the total area the cross sections of the inner side flushing channels of the crown is found from the ratio

S = (0.1 ÷ 0.3) S _n ,

where S is the total cross-sectional area of the inner side flushing channels of the crown;

S _n - the total cross-sectional area of the additional cylindrical washing channels;

wherein additional cylindrical washing channels are located perpendicular to the working end of the crown and are radially offset to the periphery of the matrix pilot, and the diameter of the additional cylindrical washing channel is determined by the dependence

$$d=2\sqrt{\frac{Q}{\pi \epsilon nV}},$$

where d is the diameter of the additional cylindrical washing channel;

Q is the flow rate of flushing fluid;

V is the flow rate of the washing fluid;

ε is the compression ratio of the jet (ε = 0.62 ÷ 0.64);

n is the number of additional cylindrical flushing channels in the diamond crown,

in addition, the input edges of the additional cylindrical washing channels are conical with an acute angle α at the apex of the cone, and the inclined washing channels are made with a variable capacity, increasing towards the outer annular groove of the crown body.

Due to the fact that the total cross-sectional area of the inner side flushing channels of the crown is found from the ratio

$$\text{S}=\text{(0}\text{,one}÷\text{0}{\text{, 3) S}}_{\text{n}},(\mathrm{one})$$

where S is the total cross-sectional area of the inner side flushing channels of the crown;

S _n - the total cross-sectional area of the additional cylindrical washing channels,

during drilling, such a distribution of the flow of flushing fluid in the diamond stepped drill bit at the bottom of the borehole in which most of it passes through additional cylindrical flushing channels without washing the core, and a smaller part seeps through the narrow internal lateral flushing channels, with a weakening head and only washes the core without its intense erosion. This leads to an increase in the safety of the selected rock core.

Due to the fact that additional cylindrical flushing channels are located perpendicular to the working end face of the crown and are shifted along the radius to the periphery of the pilot of the matrix, the destruction efficiency of the angular portion of the bottom of the well increases.

Diamond drilling studies carried out at Tula NIGP OJSC established (Yu. E. Budyukov, VI Vlasyuk, VI Spirin, “Diamond rock cutting tools” - Tula: IPP “Grif and K”, 2005. - 288 s ., ill.) that the section of the interface zone of the bottom with the wall of the well has a higher energy intensity of destruction compared to the rest of the bottom. Therefore, the liquid jets emerging from the additional cylindrical channels and directed to the angular section of the bottom of the well, which is destroyed when drilling by the periphery of the pilot of the matrix, will reduce the energy intensity of the destruction of this part of the bottom.

Due to the fact that the diameter of the additional cylindrical channel is determined by the dependence

$$d=2\sqrt{\frac{Q}{\pi \epsilon nV}},(2)$$

where d is the diameter of the additional cylindrical washing channel;

Q is the flow rate of flushing fluid;

V is the flow rate of the washing fluid;

ε is the compression ratio of the jet (ε = 0.62 ÷ 0.64);

n is the number of additional cylindrical flushing channels in the diamond crown,

in addition, the inlet edges of the additional cylindrical washing channels are conical with an acute angle at the apex of the cone, and the inclined washing channels are made with a variable capacity increasing towards the outer annular groove of the crown body, a compact jet with a high hydro-monitor effect is formed in each additional cylindrical washing channel, which allows to increase the efficiency of rock destruction at the bottom, its rapid removal from the destruction zone, thereby increasing the mechanical speed growth of diamond drilling crown and crown durability.

The flow rate of the washing liquid from the additional cylindrical washing channel can be determined by the well-known Toricelli formula (P.P. Chugaev. Hydraulics. - L .: Energoizdat, 1982 - 672 p.)

$$V=\sqrt{2gh},(3)$$

where V is the flow rate of the washing liquid from the additional cylindrical washing channel;

g is the acceleration of gravity;

h is the pressure of the flushing fluid.

A correction, called the velocity coefficient φ, is usually introduced into the Toricelli formula. When this amendment is taken into account, the flow rate of the flushing fluid will be

$$V=\varphi \sqrt{2gh},(\mathrm{four})$$

where V is the flow rate of the washing liquid from the additional cylindrical washing channel;

g is the acceleration of gravity;

h is the pressure of the flushing fluid;

φ is the velocity coefficient.

The volumetric flow rate of the flushing fluid flowing from the additional cylindrical channels of the diamond crown can be determined by the well-known formula (IL Povkh. Technical hydromechanics. L. “Mechanical Engineering” 1976-504 p.)

$$Q=\varphi \epsilon \cdot S\sqrt{2gh},(5)$$

where Q is the flow rate of the flushing fluid;

φ is the velocity coefficient (φ = 0.94 ÷ 0.99);

ε is the compression ratio of the jet (ε = 0.62 ÷ 0.64);

S is the total cross-sectional area of the additional cylindrical flushing channels of the diamond crown;

g is the acceleration of gravity;

h is the pressure of the flushing fluid.

The total cross-sectional area of the additional cylindrical flushing channels in the diamond crown is determined by the dependence

$$S=\frac{\pi d^2}{\mathrm{four}}n,(6)$$

where S is the total cross-sectional area of the additional cylindrical flushing channels of the diamond crown;

d is the diameter of the additional cylindrical washing channel;

n is the number of additional cylindrical flushing channels in the diamond crown.

Solving equation (5) taking into account expressions (4) and (6) with respect to diameter d, we find

$$d=2\sqrt{\frac{Q}{\pi \epsilon nV}},(7)$$

where d is the diameter of the additional cylindrical washing channel;

Q is the flow rate of flushing fluid;

V is the flow rate of the washing fluid;

ε is the compression ratio of the jet (ε = 0.62 ÷ 0.64);

n is the number of additional cylindrical flushing channels in the diamond crown.

The diamond stepped drill bit consists of a housing 1 with an outer annular groove 11, a diamond-containing matrix 2 with a pilot 7, divided into sectors 10 by flushing channels: end - 5, side internal 6 and external 3, inclined 4, additional cylindrical channels 8 with input edges 9 (figure 1, 2).

The diamond stepped drill bit works as follows: when creating circumferential and axial forces, the rock is destroyed by the crown, while the flushing fluid inside the crown body 1 is divided into two unequal volumes of flow: a smaller volume seeps through the narrow internal side flushing channels 6, cools the internal cutting diamonds, loses part of the pressure and only washes the core without erosion. A larger flow passes through additional cylindrical channels 8, is formed in them into a compact stream and, thanks to the hydromonitoring effect, intensively destroys the face rock weakened by diamond cutters, the destroyed parts of which are completely removed from the face, including large ones, which excludes the possibility of their secondary grinding.

Due to this embodiment of the diamond stepped drill bit, the axial and circumferential forces transmitted to it ensure effective destruction of the rock and its removal from the bottom with minimal wear of the working part of the crown, maximum drilling speed and high core safety.

The technical and economic efficiency of the proposed technical solution is to increase the operational stability and mechanical speed of rock drilling with high core safety.

The economic effect on one diamond crown with a diameter of 76 mm is 4000 rubles.

Claims (1)

Diamond stepped drill bit, including a diamond-containing matrix with a pilot, separated by end, inner and outer side, inclined and additional cylindrical flushing channels that exit into the end flushing channels, into sectors and a body with an outer ring groove, characterized in that the total cross-sectional area of the inner the side flushing channels of the crown is found from the relation S = (0.1 ÷ 0.3) S _n , where S is the total cross-sectional area of the internal side flushing channels of the crown ; S _n - the total cross-sectional area of the additional cylindrical washing channels; wherein additional cylindrical washing channels are located perpendicular to the working end of the crown and are radially offset to the periphery of the matrix pilot, and the diameter of the additional cylindrical washing channel is determined by the dependence $$d=2\cdot \sqrt[]{\frac{Q}{\pi \epsilon nV}},$$

where d is the diameter of the additional cylindrical washing channel; Q is the flow rate of flushing fluid; V is the flow rate of the washing fluid; ε is the compression ratio of the jet (ε = 0.62 ÷ 0.64); n is the number of additional cylindrical washing channels in the diamond crown, in addition, the input edges of the additional cylindrical washing channels are made conical with an acute angle at the apex of the cone, and the inclined washing channels are made with a variable capacity that increases towards the outer annular groove of the crown body.

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