Note: Descriptions are shown in the official language in which they were submitted.
Docket CH-6019
DRI LL TOOL FOR DEEP WELLS
The subject of the invention is a rotary drill
tool for deep wells consisting of a threaded stud for
a connection with a drill string or with a steel connect-
ing body including a similar rotary drive, whose head is
5 provided with c~tting members, which extend from the base
region of the head into its retracted central region,
which are collected in projecting row or strip-l;ke groups
over the exterior surface of the tool and are supported
in a bonding substance.
In known rotary drill tools of this typ~, the
cutting members of natural or synthetic diamond or poly-
crystalline diamond are supported in a matrix bonding
substance which is mounted on the steel connecting body.
Usually tungsten carbide alloyed with copper is used as
15 the bond in the matrix bonding substance. This material
possesses a high erosion and abrasion resistance but is
very expensive due to its cemented carbide content.
In spite of this, a great layer thickness is
required to absorb the thermal stresses which arise in
20 the manufa~turing process to prevent crack formation, so
that the amDunt of expensive and scarce matrix material
required is attributable as a disadvantage of known rotary
~ drill tools.
`~ The task which is basic to the invention consists,
25 with a rotary drill tool of the above-named type, of arrang-
ing the matrix bonding compound in such a way that the pro-
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portion of expensive material can be reduced w;thout reduc-
ing the mechanical properties of the tool.
This task is solved in a rotary drill tool of the
above-named type by the fact that the arrangement of the
5 matrix bonding substance in the region of the protruding
strip or row-like groups with cutting members or cutting
coatings is reduced, that the matrix bonding substance is
formed as a layer, and that the space between the above-
named layer and the steel connecting body is provided with
10 a filler, e.g., steel.
The web or rib-like construction of the blades
which surroun~ the matrix bonding subtance has as a conse-
quence that thermal stresses can appear at the circumfer-
ence only partially. Therefore, no addition to the share
15 of thermal stress ensues and the dreaded layer cracks
are avoided. The thickness of the matrix bonding layer
itself can be reduced with the above-mentioned construction
of the blades if the compound is replaced ~y filler in
the core region. Saving of matrix material thus occurs
20 in twofold consideration~
Steel, for example is a suitable filler, wlth
which the space between the matrix bonding compound layer
and the steel connecting body is filled and subse~uently
bonded by means of a sintering process.
A special advantage of this intermediate layer
lies in the buffering effect relative to the steel connect-
ing body which expands against the graphite mold during
the heating process.
The matrix bonding compound may be applied to
30 the surface as a uniformly thick layer in a tangential
direction and orthogonal to it if it is expected that
the formation of uniform abrasion will occur in the appli-
cation of the rotar~ drill tool or also adjuste~ according
to the degree of the abrasion and erosion forces occurring
at various locations ~f the t~l during drilling. In
addition, a choice of various abrasion-resistant material
may be made taking the expected wear ~orces into consider-
a~ion.
In all the above-mentioned design forms, preformed
wear-resistant supportin~ bodies may be inserted into the
matrix b~nding compound or into the filler, onto which
diamond layer cutting elements (e.g., sintered polycrystal-
line diamond) may be s~ldered after the man~facturing pro-
- 10 cess of the tool body.
Similarly, man-made or natural diamonds may be set
into the surface of the matrix layer or small caliber dia-
monds may be împregnated directly into the matrix bonding
compound. Beyond this, combinations of the ab~ve-mentioned
15 cutting materials are possible.
The nozzles or g~tters, with passage channels to
a eentral hole which are usual for removal of ~rîll cuttings
and cooling the cutting, may be înserted into the matrix
material or shaped out of the matrix substance and, if
2D desired, out of the filler.
In a special design form of the nozzles, the
passage channels are directed out to the surface vf the
tool with a constant cross-section, and, preferentially~
have a relationship of diameter to length in the region
25 between 0.5 and 0.1.
If, in the case of certain blade proportions,
the surface area of the steel connecting ~ody usuable
for bonding must be enlarged, ridges can be welded ~nto
the connecting body in the region of the blades or studs
30 may be recessed as projections during ~achining of the
steel body.
Ridges or ribs are required when the relationship
of blade circumferential width to blade radial height
is unity or less than unity. Wear protection of the
base material between the ribs,
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which becomes necessary due to the tool geometry or drill-
ing conditions may be achieved b~ jacketting the base
material with an anti-wear lining of suitable materials
by welding, flame or plasma spraying onto the steel con-
5 necting body.
Additional characteristics and advantages of
the invention are shown in the claims and in the following
description in connection with ~he drawing, in which con-
struction examples of the sub~ect of the inventi~n are
10 illustrated. In the drawing are shown:
Fig. 1 a graphic representation of a ~irst rotary drill
tool with blades which are formed as studs and
which carry preformed cutting layers fastened
to supports. The flushing fluid is conducted
1~ through nozzles.
Fig. 2 a second rotar~ drill tool, whose blades are
formed as those in Fig. 1, but in wh;ch the
flushing liquid is conducted by way of gutters.
Fig. 3 a third rotary drill tool with flat studs,
whose tangential surface contains cutting
particles and form a cutting layer and which
are perforated by waterways according to a
defined configuration.
Fig. 4, 5 show cross-sections through various construction
~designs of a rotary drill tool according to
Fig. 1.
Fig. 6, 7 show cross-sections through various construction
& 8 designs of a rotary drill tool according to
Fig. 2.
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Fig. 9,10 show cross-sections through various constr~c-
tion desi~ns of a rotary drill tool according
to Fig. 3~
In Fig. 1, a rotary drill tool is represented
5 which includes a steel connecting body 7 and three stud
shaped blades which, at times, extend from the outer radius
of the tool to the center. The blades have preformed
cutter tips with polycrystalline sintered diamond which
are fastened to the supports which are partially inserted
10 into the stud and the whole designated as 1.
Inside the steel connecting body 7, a central
drilled hole and passage channels for the flush are pro-
vided to supply the tool with flushing liquid. These
flow into nozzles 5.
The blades inside the nozzles are exposed to
strong abrasive forces during drilling and have an abra-
sion and erosion-resistance surface made of matrix bonding
: substance 3. The remainder of the steel body is unprotected
or provided with an anti-wear lining 6 by welding, flame or
20 plasma spraying a suitable material onto the connecting
body.
For visualization of the buildup of a stud, cross-
sections through a stud according to ~he design of Fig~ 1
are represented in Fig. 4 and 5. A stud with a blade part,
25 the whole designated as 1, is arranged on a steel connecting
body 7. The stud consists of an outer layer of matrix bond-
ing compound 3, ~hich, as described above, is very abrasion
and erosion-resistant through the addition of a wear-resis-
tant material, e.g., a carbide. On the other hand, an
30 inner core 4 is composed of steel which i5 bonded by means
of sintering processes with or without ~he addition of
binder. - - -
In addition to main use as a mount and support forthe blade members.l, the matrix bonding compound 3 or the
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steel core 4 serves also to protect the nozzles 5, ~hich
convey the flushing liquid. The remainder of the steel
connecting body can be provided with an armored coating 6,
which as already described above, can be applied by welding,
5 flame or plasma spraying a suitable material ~nto the con-
necting body.
The difference between the stud illustrated in
Fig. 5 and the ~ne in Fig. 4 consists o~ its greater height.
This stud has a strip 8 to enlarge the usable area for bond-
10 ing to the steel connecting body 7, which, for example, waswas welded onto the steel connecting body 7 or was recessed
as a projection during manufacture.
Examples of how a partially produced matrix bonding
substance 3 with steel core 3 is also suitable for the pro-
15 duction of other tool ~hapes are given in the second toolillustrated in Fig. 2 as well as in the appropriate cross
sections of Fig. 6, 7, 8. While maintaining the blade
members 1 described in connection with Fig. 1, 4 and 5
open gutters~9) are provided on the outside instead of
20 nozzles. The gutters are inser~ed or shaped into the
matrix bonding substance and which flow into the passa9e
channels connecting with the central hole in the interior
of the tool. The outer, abrasion resistant, layer of the
gutters 9 is co-drawn into the interior following the outer
25 contour, so that approximately equal thickness of abrasion
resistant material is encountered on all the surface loca-
tions of the stud including the inserted gutters. A strip
8 according to Fi~. 7 is provided when the height of the
stud is greater, which fulfills the same purpose as ~hat
30 described in connection with the design in Fig. 5.
Fig. 8 shows a design of a stud of low height,
where a recess exists-in the steel connecting body 7 to
receive the matrix bonding subs~ance 3 and the steel core
12.
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In a third drill tool, accord~ng to Fig. 3, instead
of prefabricated, precisely positionea blade members, layers
made of a cutting material with, for example, natural dia-
monds bonded into the matrix bonding subtance are formed as
5 the outer tangential surface of the ribs and form a cutting
coating 2. This cutting coating ~ is interrupted and passed
through in a kind of tire tread profile by gutters 9, into
which, as described with the second rotary drill tool
(Fig. 2) the channels connecting with the central hole
10 fl~w.
The design represented in cross-section in
Fig. 9, 10, on the other hand, corresponds to the remain-
ing design shapes which have been dealt with, with respect
to the arrangement of the matrix bonding substance 3 and
15 the steel core 4.
