U.S. patent application number 11/141222 was filed with the patent office on 2006-11-30 for directable nozzle for rock drilling bits.
Invention is credited to Roy Estes.
Application Number | 20060266557 11/141222 |
Document ID | / |
Family ID | 37461978 |
Filed Date | 2006-11-30 |
United States Patent
Application |
20060266557 |
Kind Code |
A1 |
Estes; Roy |
November 30, 2006 |
Directable nozzle for rock drilling bits
Abstract
A directable nozzle assembly 100 for a rotary drill bit 10 is
disclosed, having a nozzle 110 comprising a generally spherical
body 112, and having an extension 114 extending from the body 112.
A passage 116 extends through the body 112 and extension 114
portions. A seal 130 is provided for sealing the nozzle 110 to the
nozzle boss area 14 of the rotary drill bit 10. A removable
retainer 140 is provided having a hollow interior, an angle limiter
surface 146, and an interior compression surface 150. In another
embodiment is a wear resistant sleeve 160, having a collar 162 with
a nozzle seat 164 and a body 170, inserted into a flow port 12 of
rotary drill bit 10.
Inventors: |
Estes; Roy; (Weatherford,
TX) |
Correspondence
Address: |
STORM LLP
BANK OF AMERICA PLAZA
901 MAIN STREET, SUITE 7100
DALLAS
TX
75202
US
|
Family ID: |
37461978 |
Appl. No.: |
11/141222 |
Filed: |
May 31, 2005 |
Current U.S.
Class: |
175/340 ;
175/393 |
Current CPC
Class: |
E21B 10/18 20130101;
E21B 10/60 20130101 |
Class at
Publication: |
175/340 ;
175/393 |
International
Class: |
E21B 10/18 20060101
E21B010/18; E21B 10/60 20060101 E21B010/60 |
Claims
1. A directable nozzle assembly for a rotary drill bit, comprising:
a nozzle comprising: a generally spherical body; an extension
extending from the body; and, a passage extending through the body
and extension; a seal; and, a removable retainer comprising: a
hollow interior; a nozzle boss connection means; a limiter surface;
and, an interior compression surface.
2. The directable nozzle assembly of claim 1, further comprising:
wherein interference between the limiter surface and the extension
limits the angular disposition of the nozzle passage relative to
the retainer.
3. The directable nozzle assembly of claim 1, the nozzle further
comprising: a first portal formed at the intersection of the
passage and the body; and, a second portal formed at the
intersection of the passage and the extension.
4. The directable nozzle assembly of claim 2, further comprising:
the limiter surface preventing location of the first portal beyond
a flow port in a rotary drill bit.
5. The directable nozzle assembly of claim 1, wherein the nozzle
boss connection means further comprises a threaded external
surface.
6. The directable nozzle assembly of claim 1, the retainer further
comprising: the limiter surface being frustum shaped.
7. The directable nozzle assembly of claim 1, the retainer further
comprising: the interior compression surface being spherically
shaped.
8. The directable nozzle assembly of claim 1, the retainer further
comprising: a wrench receptacle on a first end.
9. The directable nozzle assembly of claim 1, the retainer further
comprising: a second end seal surface; and, wherein the seal
surface restricts expansion of a packing seal.
10. A directable nozzle assembly for a rotary drill bit,
comprising: a nozzle comprising: a generally spherical body; an
extension extending from the body; a passage extending through the
body and extension; a first portal formed at the intersection of
the passage and the body; a second portal formed at the
intersection of the passage and the extension; and, a hollow sleeve
comprising: a collar having a seat receivable of the nozzle body; a
body insertable into a flow port of a rotary drill bit; and, a
seal; and, a removable retainer comprising: a hollow interior; a
nozzle boss connection means; a limiter surface; and, an interior
compression surface.
11. The directable nozzle assembly of claim 10, the sleeve further
comprising: wherein the collar of the sleeve is receivable in a
seal groove of a rotary drill bit.
12. The directable nozzle assembly of claim 10, further comprising:
wherein the outside diameter of the body is receivable in close
tolerance fit within a flow port of a drill bit.
13. The directable nozzle assembly of claim 10, further comprising:
wherein the outside diameter of the body is receivable in
interference fit within a flow port of a drill bit.
14. The directable nozzle assembly of claim 10, the sleeve further
comprising: a taper at the end of the body opposite to the
collar.
15. The directable nozzle assembly of claim 10, the sleeve further
comprising: a seal slot located in the collar.
16. The directable nozzle assembly of claim 10, further comprising:
wherein interference between the limiter surface and the extension
limits the angular disposition of the nozzle passage relative to
the retainer.
17. The directable nozzle assembly of claim 10, further comprising:
the limiter surface preventing location of the first portal beyond
a inside diameter of the sleeve body.
18. The directable nozzle assembly of claim 1, wherein the nozzle
boss connection means further comprises a threaded external
surface.
19. The directable nozzle assembly of claim 10, further comprising:
wherein the sleeve is made of a material having a hardness greater
than the hardness of a flow port of a rotary drill bit in which the
sleeve is installed.
20. The directable nozzle assembly of claim 10, further comprising:
wherein the sleeve is made of tungsten carbide or titanium
carbide.
21. A rotary drill bit, adapted for use with a directable nozzle
assembly, comprising: a flow port; a nozzle boss connected to the
flow port; a retainer connection means; a groove for receiving a
seal; and, a spherical segment shaped nozzle seat adapted for
complementary engagement with a spherical nozzle body.
22. The rotary drill bit of claim 22, further comprising: the
nozzle seat being in the shape of a spherical section.
23. The rotary drill bit of claim 22, the retainer connection means
further comprising: an internally threaded portion.
24. The rotary drill bit of claim 22, further comprising: a bore
relief; and, a packing seal located in the bore relief.
25. A rotary drill bit, comprising: a flow port; a nozzle boss
connected to the flow port; a retainer connection means; a groove
for receiving a seal; a spherical segment shaped nozzle seat; a
seal located in the groove; a nozzle comprising: a spherical body
complementarily engaged with the nozzle seat; an extension
extending from the body; and, a passage extending through the body
and extension; and a removable retainer comprising: a hollow
interior; a nozzle boss connection means connected to the retainer
connection means; a limiter surface through which the extension of
the nozzle extends; and, a spherical segment interior compression
surface complementarily engaged with the nozzle body.
26. A rotary drill bit, comprising: a flow port; a nozzle boss
connected to the flow port; a retainer connection means; a bore
relief; a groove; a seal located in the bore relief; a nozzle
comprising: a generally spherical body; an extension extending from
the body; a passage extending through the body and extension; a
hollow sleeve made of wear resistant material, comprising: a collar
located in the groove of the nozzle boss; a spherical segment
shaped nozzle seat on the collar; a body located in the flow port;
and, a hollow interior; a nozzle boss connection means connected to
the retainer connection means; a limiter surface through which the
extension of the nozzle extends; and, a spherical segment interior
compression surface complementarily engaged with the nozzle body.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] None.
BACKGROUND OF THE INVENTION
[0002] 1. TECHNICAL FIELD
[0003] The present invention relates generally to drilling bits
used for drilling earth formations. More specifically, the present
invention relates to a novel design for a directable jet nozzle for
rock bits, which works in combination with a retaining system which
defines limits of angular orientation.
[0004] 2. DESCRIPTION OF RELATED ART
[0005] In the exploration of oil, gas, and geothermal energy,
drilling operations are used to create boreholes, or wells, in the
earth. These operations normally employ rotary and percussion
drilling techniques. In rotary drilling, the borehole is created by
rotating a tubular drill string with a drill bit secured to its
lower end. As the drill bit deepens the hole, tubular segments are
added to the top of the drill string. While drilling, a drilling
fluid is continually pumped into the drilling string from surface
pumping equipment. The drilling fluid is transported through the
center of the hollow drill string and into the drill bit. The
drilling fluid exits the drill bit at an increased velocity through
one or more nozzles in the drill bit. The drilling fluid then
returns to the surface by traveling up the annular space between
the borehole and the drill string. The drilling fluid carries rock
cuttings out of the borehole and also serves to cool and lubricate
the drill bit.
[0006] One type of rotary rock drill is a drag bit. Early designs
for drag bits included hard facing applied to steel cutting edges.
Modern designs for drag bits have extremely hard cutting elements,
such as natural or synthetic diamonds, mounted to a bit body. As
the drag bit is rotated, the hard cutting elements scrape against
the bottom and sides of the borehole to cut away rock.
[0007] Another type of rotary rock drill is the roller cone bit.
These drill bits have rotatable cones mounted on bearings on the
body of the drill bit, which rotate as the drill bit is rotated.
Cutting elements, or teeth, protrude from the cones. The angles of
the cones and bearing pins on which they are mounted are aligned so
that the cones roll on the bottom of the hole with a controlled
amount of slippage. One type of roller cone cutter is an integral
body of hardened steel with teeth formed on its periphery. Another
type has a steel body with a plurality of tungsten carbide or
similar inserts of high hardness that protrude from the surface of
the body. As the roller cone cutters roll on the bottom of the hole
being drilled, the teeth or carbide inserts apply a high
compressive load to the rock and fracture it. The cutting action of
roller cone cutters is typically a combination of crushing,
chipping and scraping. The cuttings from a roller cone cutter are
typically a mixture of moderately large chips and fine
particles.
[0008] When drilling rock with a roller cone cutter, it is
imperative to remove the cuttings from the bottom of the hole.
Failure to remove the cuttings from the hole-face will result in
redrilling the cuttings. Redrilling rock cuttings substantially
reduces the rate of penetration and causes premature failure of the
roller cone drill bit. Roller cone drill bit cutting structures and
bearing systems are both susceptible to premature failure when
cuttings are not promptly removed from the hole-face when drilling.
As an example, cutting structures may begin to track in a pattern
that prevents normal progressive drilling. Build-up of cuttings or
grindings of rock may quickly erode the metal surrounding the
inserts, reducing the area of retention. This may allow inserts to
be released in a catastrophic failure of the drill bit. Similarly,
cuttings and grinds may build-up behind journal shirttail sections
causing erosion and exposure of ball-plugs and seals, also
resulting in catastrophic failure of the drill bit.
[0009] The importance of optimizing drilling hydraulics in oil and
gas exploration has long been known. Drill bit manufacturers
provided plastic slide rules to operators and contractors for many
years, allowing them to calculate the various hydraulic components.
In the late 1970's, Field Engineers used programmable calculators
for the same purpose. In 1980, Reed Rock Bit.RTM. introduced an
interactive microcomputer program for Field Engineers planning well
drilling and hydraulics programs. A goal of these calculations,
however made, was the proper selection of nozzles for the drill
bits.
[0010] Various theories of hydraulics optimization have been
advanced in oil and gas exploration. One popular theory relies upon
maximization of a calculated numeric known as Hydraulic Horsepower.
Another popular theory relies upon maximization of a calculated
numeric known as Jet Impact Force. Both theories depend upon
calculation of the pressure losses in the drilling system and
allocating the optimum amount of remaining available pressure loss
through the nozzles. Utilization of the theoretical optimum
available pressure loss is achieved, in part, by increasing or
decreasing the velocity through the nozzles. The velocity is
adjusted by changing the cross-sectional area of the nozzle through
which the fluid flows. Since nozzles in conventional drilling bits
are interchangeable, this is easily accomplished.
[0011] Coincident to the practice of optimizing jet nozzle
selection, it is known that the distance between the nozzle exit
and the hole-face is an important factor in optimizing drilling
hydraulics, and thus rate-of penetration. The closer the nozzle
exit to the hole-face, the better the bottom hole cleaning
properties. As the nozzle exit approaches the hole-face, there is
less intervening turbulent flowing drilling fluid to interfere with
the cleaning action of the fluid flowing from the nozzle.
Conventional drill bits are limited by manufacturing practices as
to how far up nozzle bosses can be manufactured, and still allow
journals to be turned on machine centers. There is also a
counterbalancing constraint requirement to provide sufficient
return area across the drill bit for drilling fluid and cuttings to
navigate the drill bit geometry in transit to the annulus of the
well bore.
[0012] In addition to proximity to the hole-face, it has been
determined that the angularity with which the fluid strikes the
bottom of the hole can have a substantial impact on the hydraulic
cleaning of the hole-face, and thus rate-of penetration. Drill bits
and formations have different physical characteristics, leaving the
optimum angle of nozzle direction relegated somewhat to
experimentation between drill bits and formations. Additionally,
the practice of high-speed drilling in which drill bits are rotated
in excess of 100 rpm can change the optimum angle of nozzle
direction. There is a counterbalancing constraint in which
excessive angular disposition of the nozzle may contribute to cone
erosion or seal exposure.
[0013] Numerous attempts have been made to provide a commercially
practical directable nozzle design, as well as extended nozzle
designs. U.S. Pat. No. 6,585,063 issued to Larsen discloses a
multi-stage diffuser nozzle for rolling-cutter bits. The nozzle may
comprise two or more portions, including a diffuser upstream of the
nozzle outlet and a multi-outlet nozzle. The nozzle must be
oriented as it is inserted and fixed in a given orientation.
[0014] U.S. Pat. No. 6,571,887 issued to Nguyen et al. discloses a
nozzle retention body welded to the bit body between adjacent bit
legs. The nozzle retention body may be of differing configuration
and orientation, but it retains a generally conventional
nozzle.
[0015] U.S. Pat. No. 6,390,211 issued to Tibbitts discloses a
ball-mounted nozzle for a fixed-cutter bit or a rolling-cutter bit.
The nozzle body is spherical and seats in a spherical receptacle. A
retainer ring is used to secure the nozzle against rotation in the
seat. U.S. Pat. No. 6,186,251 issued to Butcher discloses modifying
the nozzle size or orientation with the intention of modifying the
force balance.
[0016] U.S. Pat. No. 5,992,763 issued to Smith et al. discloses a
nozzle having an indentation adjacent the nozzle opening or exit to
enhance the flow of drilling fluid entrained near the face of the
nozzle. U.S. Pat. No. 5,967,244 issued to Arfele discloses an
"indexed" nozzle for fixed-cutter bits. The nozzle has a grooved
exterior with corresponding grooves in a lock ring.
[0017] A primary disadvantage of several of the known art designs
is that they are difficult and expensive to manufacture. Several of
the designs are not compatible with the nozzle boss on standard
rock bits having interchangeable nozzles. When modifications to the
bit itself are required, the several costs associated with
non-standard designs, such as tooling and machine set-ups, further
increase the cost.
[0018] Another disadvantage of several of the known art designs is
the time required for assembly of the drill bits. In the drilling
industry, drill bit selection decisions are often made while
drilling, in response to the drilling rate achieved and the
condition of the dull bit removed from the hole. Several of the
known art designs require welding operations which have proven to
be an impediment to their acceptance in the drilling industry.
[0019] Another disadvantage of several of the known art designs is
that they are not reusable. Sintered tungsten carbide nozzles are
expensive, and operators expect to be able to reuse them. When dull
drill bits are removed from the well, nozzles are removed and
reused or recycled.
[0020] A significant disadvantage of the known art directable
nozzle designs is that they are capable of being aligned in a
manner that creates excessive turbulence around the nozzle boss and
seal areas, resulting in hydraulic erosion of the steel around the
nozzle boss, known-as "wash-outs," and premature failure of the
drill bit.
[0021] Another significant disadvantage of the known art directable
nozzles is that they are capable of being aligned in a manner
detrimental to the hydraulic performance of the drill bit. Still
another significant disadvantage of the known art directable
nozzles is that they are capable of being aligned in a manner which
can result in improper alignment and premature bit failure from
erosion of cones and/or exposure of journal bearing seals.
[0022] Thus it can be seen that, collectively, the known art fails
to resolve the issue of a need for a directable nozzle that is
inexpensive to manufacture, that is cost effective, that is easy to
install, that is reusable, that has a restricted range of
disposition, that avoids wash-outs, and that avoids poor hydraulic
performance from misalignment.
SUMMARY OF THE INVENTION
[0023] The present invention is a significant improvement over that
described in the above enumerated known directable nozzle designs.
References to the present invention are intended to refer to one of
more of the various embodiments disclosed of which can be inferred
from the disclosure contained herein.
[0024] A principal advantage of the present invention is that it
provides a nozzle system that has a designed restricted
directability. As a result of this feature, rig floor assemblies by
untrained personnel can be completed without risk of various
problems associated with known directable nozzle designs. A benefit
of this feature is that the present invention prevents excessive
nozzle angularity resulting in internal turbulence around the
nozzle boss and seal areas, hydraulic erosion and premature failure
of the drill bit. Another benefit of this feature is that the
present invention prevents excessive nozzle angularity resulting in
inefficient hydraulic performance of the drill bit. Another benefit
of this feature is that the present invention prevents excessive
nozzle angularity resulting in improper alignment and premature bit
failure from erosion of cones and/or erosion of shirttail regions
and exposure of journal bearing seals.
[0025] Another advantage of the preferred embodiment of the present
invention is that it is inexpensive and easier to manufacture than
conventional designs. The design is compatible with the nozzle boss
on standard rock bits having interchangeable nozzles. Another
advantage of the present invention is the time required for
assembly of the drill bits. No welding is required, and nozzle size
selections can be made at the rig floor, immediately prior to
connecting the drill bit to the drill string. This is critical as
optimization of the nozzle selection requires knowledge of the
drilling fluid and hydraulic system parameters at the time and
depth the previous drill bit is removed from the wellbore.
[0026] Another advantage of the present invention is that it is
reusable. Other advantages of the present invention will become
apparent from the following descriptions, taken in connection with
the accompanying drawings, wherein, by way of illustration and
example, an embodiment of the present invention is disclosed.
[0027] In carrying out principles of the present invention, in
accordance with a preferred embodiment thereof, a directable nozzle
assembly for a rotary drill bit is disclosed, having a nozzle
comprising a generally spherical body, and having an extension
extending from the body. A passage extends through the body and
extension portions. A seal is provided for sealing the nozzle to
the nozzle boss area of the rotary drill bit. A removable retainer
is provided having a hollow interior, a threaded external surface,
an angle limiter surface, and an interior compression surface.
[0028] In another preferred embodiment, the angle limiter surface
is frustum shaped. In another preferred embodiment, the interior
compression surface is spherically shaped. In another preferred
embodiment, the retainer has a wrench receptacle on a first end. In
still another preferred embodiment, the retainer has a second end
seal surface which restricts expansion of a packing seal. In the
preferred embodiment, the limiter surface of the retainer prevents
misalignment between a first portal of the nozzle body and the flow
port of a rotary drill bit.
[0029] In an alternative preferred embodiment, the nozzle has a
first portal on the spherical body and a second portal on the
extension portion. An erosion resistant hollow sleeve is provided,
having a collar portion with a spherical seat for receiving the
nozzle body. The sleeve also has a hollow cylindrical body portion.
A seal is provided for sealing the sleeve to the nozzle boss area
of the rotary drill bit. In a more preferred embodiment, the body
has a tapered end. In the preferred embodiment, the angle limiter
surface of the retainer prevents misalignment between the first
portal of the nozzle body with the hollow center of the sleeve.
Additional features are presented in detail herein below.
BRIEF DESCRIPTION OF THE DRAWINGS
[0030] FIG. 1 is an isometric view of a rotary drill bit having a
directable nozzle assembly installed in accordance with a preferred
embodiment of the present invention.
[0031] FIG. 2 is a top view of the rotary drill bit of FIG. 1,
illustrating multiple directable nozzle assemblies installed in
accordance with a preferred embodiment of the present
invention.
[0032] FIG. 3 is a side-sectional view of a known art
interchangeable nozzle assembly installed in a rotary drill
bit.
[0033] FIG. 4 is an exploded side-sectional view of the components
of a directable nozzle assembly in accordance with a preferred
embodiment of the present invention, as shown in reference to a
rotary drill bit.
[0034] FIG. 5 is a side-sectional view of the preferred embodiment
disclosed in FIG. 4, illustrating the nozzle directed in an axis
parallel to the axis of the flow port of the rotary drill bit.
[0035] FIG. 6 is a side-sectional view of the preferred embodiment
disclosed in FIGS. 4 and 5, illustrating the nozzle directed in an
axis of maximum angular relation to the axis of the flow port of
the rotary drill bit.
[0036] FIG. 7 is a side-sectional view of a directable nozzle
assembly, installed in a rotary drill bit, and utilizing an erosion
resistant sleeve in accordance with another preferred embodiment of
the present invention.
[0037] FIG. 8 is a side-sectional view of an extended directable
nozzle assembly, installed in a rotary drill bit, utilizing an
erosion resistant sleeve in accordance with another preferred
embodiment of the present invention.
[0038] FIG. 9 is a side-sectional view of a directable nozzle
assembly, installed in a rotary drill bit, utilizing an erosion
resistant sleeve, and having a seal disposed within the sleeve, in
accordance with another preferred embodiment of the present
invention
DETAILED DESCRIPTION OF THE INVENTION
[0039] FIG. 1 is an isometric view of a rotary drill bit 10 having
a directable nozzle assembly 100 installed in accordance with a
preferred embodiment of the present invention. FIG. 2 is a top view
of rotary drill bit 10 of FIG. 1, illustrating multiple directable
nozzle assemblies 100 installed in accordance with a preferred
embodiment of the present invention.
[0040] FIG. 3 is a side-sectional view of a known art
interchangeable nozzle assembly 200 installed in a nozzle boss 14
of rotary drill bit 10. In the view, it is seen that a nozzle 210
is non-directable. Nozzle 210 is secured in fixed alignment with a
flow port 12 in rotary drill bit 10. A seal 130 is located in a
groove 16 to prevent drilling fluid from bypassing nozzle 210.
Drilling fluid passes through flow port 12 of rotary drill bit 10
and then through a nozzle passage 216 of nozzle 210. The drilling
fluid enters a first portal 218 and exits a second portal 220,
which is significantly smaller in diameter than first portal 218.
Nozzle 210 is secured in position by a retainer 240. Retainer 240
has a nozzle boss connection means for securing retainer 240 to
rotary drill bit 10. Most conventional nozzle boss connection means
incorporate threaded external surfaces 244 which is thread
connectable to a threaded portion 22 of nozzle boss 14 to hold
nozzle assembly 200 in place.
[0041] FIG. 4 is an exploded side-sectional view of the components
of directable nozzle assembly 100 in accordance with a preferred
embodiment of the present invention, as shown in reference to
rotary drill bit 10. A nozzle 110 is provided, having a spherical
body portion 112. An extension portion 114 extends from body 112. A
nozzle passage 116 extends throughout body 112 and extension 114.
Nozzle passage 116 has a first portal 118 located on body 112. A
second portal 120 is located on extension 114.
[0042] A retainer 140 is provided, having a functionally unique
structure. Retainer 140 has a nozzle boss connection means 144. In
the preferred embodiment, nozzle boss connection means 144 is a
threaded external surface 144. Retainer 140 may have a wrench
receptacle 142 on its top surface, and a limiter surface 146
extends downward and inward from the top of retainer 140. In the
preferred embodiment, limiter 146 is contoured for complementary
engagement with extension 114. In a more preferred embodiment,
limiter 146 forms a frustum, or conic section, for engagement with
a generally cylindrical extension 114.
[0043] A contoured compression surface 150 extends downward from
limiter 146. In a preferred embodiment, compression surface 150 is
contoured for complementary engagement with nozzle body 112. In a
more preferred embodiment, compression surface 150 forms a
spherical segment. Also in a preferred embodiment, a small chamfer
148 is located between limiter 146 and compression surface 150.
[0044] As with conventional rotary drill bits previously described,
rotary drill bit 10 has a flow port 12. A nozzle boss 14 is formed
on rotary drill bit 10 for receiving nozzle assembly 100. In the
preferred embodiment, nozzle boss 14 has a retainer connection
means 22. In the preferred embodiment, retainer connection means is
a threaded portion 22 for threaded coupling to retainer 140. A
groove 16 is receivable of a seal 130. A bore relief 20 may
separate threaded portion 22 from groove 16. A base 18 is formed at
the bottom of groove 16. A nozzle seat 24 is formed below base 18.
In the preferred embodiment, seat 24 is contoured for complementary
engagement with nozzle body 112. In a more preferred embodiment,
seat 24 forms a spherical segment.
[0045] FIG. 5 is a side-sectional view of nozzle assembly 100
installed in rotary drill bit 10, illustrating nozzle 110 directed
in an axis coincident to the central axis of flow port 12, in a
manner similar to the orientation of conventional nozzle
assemblies, as illustrated in FIG. 3. FIG. 6 is a side-sectional
view of nozzle assembly 100 installed in rotary drill bit 10,
illustrating nozzle 110 directed in an axis of maximum angular
relation to the central axis of flow port 12.
[0046] FIG. 7 is a side-sectional view of an alternative preferred
embodiment of directable nozzle assembly 100, shown installed in
rotary drill bit 10. In this embodiment, nozzle assembly 100
further includes an erosion resistant sleeve 160. As seen in FIG.
7, sleeve 160 is insertable into nozzle boss 14 below nozzle 110.
Sleeve 160 has a collar 162. Collar 162 engages base 18 of nozzle
boss 14, and resides in groove 16 in place of, or in conjunction
with, seal 130. A nozzle seat 164 is formed on collar 162. In the
preferred embodiment, seat 164 is contoured for complementary
engagement with nozzle body 112. In a more preferred embodiment,
seat 164 forms a spherical segment.
[0047] Sleeve 160 has a body portion 170 that extends into flow
port 12 beyond first portal 118 of nozzle 110. In a more preferred
embodiment, a taper 172 is inscribed on the inside diameter of body
170. In this embodiment, a seal 180 is located in bore relief 20 of
nozzle boss 14 to prevent drilling fluid from bypassing nozzle 110.
In a more preferred embodiment, seal 180 is a packing seal.
[0048] FIG. 8 is a side-sectional of an alternative preferred
embodiment of directable nozzle assembly 100, shown installed in
rotary drill bit 10. In this embodiment, extension 114 of nozzle
110 is significantly extended. The significant extension of
extension 114 is compatible with all embodiments of the present
invention.
[0049] FIG. 9 is a side-sectional view of another preferred
embodiment of directable nozzle assembly 100, shown installed in
rotary drill bit 10. In this embodiment, sleeve 160 further
includes a seal groove 168 for accommodation of a seal 190. In the
preferred embodiment, seal 190 is an o-ring seal. As shown in FIG.
9, another o-ring seal 130 can be located in groove 16 to seal with
collar 162 of sleeve 160. However, the use of seal 190 is also
compatible with the embodiments disclosed in FIGS. 7 and 8, in
which seal 180 is located in bore relief 20.
[0050] The foregoing detailed description is to be clearly
understood as being given by way of illustration and example, the
spirit and scope of the present invention being limited solely by
the appended claims. In particular, and by way of example and not
limitation, it is well known to use alternative nozzle boss
connection means to retain nozzles in rotary drill bits other than
retainers with threaded connections. Conventional nozzle assemblies
alternatively include nozzles having circumferential grooves and
nozzle bosses with holes. In these assemblies, a "nail" is driven
into the hole in the nozzle boss, for intersection with the
circumferential groove to retain the nozzle. It would be readily
apparent to anyone of ordinary skill in the art that the presently
disclosed inventive embodiments can be incorporated into such
assemblies. For example, the top to nozzle boss 14 can be modified
to function as limiter surface 146, and multiple grooves can be
formed on the surface of nozzle body 112 to accept the nail at
various positions.
OPERATION OF THE INVENTION
[0051] FIG. 2 is a top view of rotary drill bit 10, illustrating
multiple directable nozzle assemblies 100 installed in accordance
with a preferred embodiment of the present invention. In this view,
it can be seen that second portals 120 are angled toward the
leading surface of the cutting structures of rotary drill bit 10.
This capability is a principal objective of the present invention.
However, excessive angularity may subject the cutting structure and
bearing system to erosion resulting in premature failure. Likewise,
excessive angular orientation can result in misalignment of flow
ports 12 and first portals 118, generating turbulence and erosion
inside rotary drill bit 10, resulting in premature failure. For
these reasons and others, another principal objective of the
present invention is to provide a predetermined, restricted range
of angular orientation of directable nozzle assemblies 100.
[0052] FIG. 4 is an exploded side-sectional view of the components
of directable nozzle assembly 100 in accordance with a preferred
embodiment of the present invention, as shown in reference to
rotary drill bit 10. As seen in the preferred embodiment
illustrated, nozzle 110 has a spherical body portion 112 that
enables multidirectional rotation of nozzle 110. This capability is
best seen in reference to FIG. 5 and FIG. 6.
[0053] Still referring to FIG. 4, extension 114 of nozzle 110
serves a dual purpose. First, extension 114 positions second portal
120 closer to the object of delivery of the drilling fluid. This is
well known and documented to improve hydraulic cleaning of the
bottom of the hole. Secondly, extension 114 provides an index for
engaging limiter 146 of retainer 140 to provide a predetermined,
restricted range of angular orientation of directable nozzles 110.
This is best seen in FIG. 6.
[0054] In the preferred embodiment, retainer 140 may have wrench
receptacle 142 on its top surface and threaded external surface 144
for threaded and removable assembly in conventional rotary drill
bits 10. Unique to the present invention, limiter surface 146
extends downward and inward from the top of retainer 140. In the
preferred embodiment, limiter 146 is contoured for complementary
engagement with extension 114. In a more preferred embodiment,
limiter 146 forms a frustum, or conic section, for engagement with
a generally cylindrical extension 114. The engagement with
extension 114 with limiter 146 defines the maximum obtainable
angular orientation of directable nozzles 110. This relationship is
illustrated in FIG. 6.
[0055] Nozzle passage 116 extends throughout body 112 and extension
114, with first portal 118 located on body 112 for entrance of the
drilling fluid, and second portal 120 located on extension 114 for
exit of the drilling fluid. Second portal 120 is generally smaller
in diameter than first portal 118. The flow of the drilling fluid
is thereby accelerated through nozzle passage 116, obtaining the
desired high-velocity necessary to improve the performance of the
rotary drill bit 10.
[0056] Referring again to FIG. 4, retainer 140 has a contoured
compression surface 150 extending downward from limiter 146. In a
preferred embodiment, compression surface 150 is contoured for
complementary engagement with nozzle body 112. In a more preferred
embodiment, compression surface 150 forms a spherical segment.
[0057] Similarly, in the preferred embodiment, rotary drill bit 10
has a nozzle seat 24 formed in nozzle boss 14 below base 18. In the
preferred embodiment, seat 24 is contoured for complementary
engagement with nozzle body 112. In a more preferred embodiment,
seat 24 forms a spherical segment.
[0058] The geometric orientation of seat 24 is inverse to that of
compression surface 150. In this configuration, as retainer 140 is
progressively threaded into nozzle boss 14 of rotary drill bit 10,
nozzle body 112 is compressed between compression surface 150 of
retainer 140 and seat 24 of rotary drill bit 10. The compressive
force on nozzle body 112 maintains nozzle 110 in place, while
resisting the high outward force generated in nozzle passage 116 by
the flow of the drilling fluid. The force against nozzle 110 is
distributed in the threaded engagement between external threads 144
of retainer 140 and threaded portion 22 of nozzle boss 14.
[0059] As with conventional rotary drill bits previously described,
nozzle boss 14 has a threaded portion 22 for threaded coupling to
retainer 140, and a groove 16 for location of a seal 130, such as
an o-ring seal. This advantageously allows convenient
interchangeability between directable nozzle assembly 100 and
conventional nozzle assembly 200 in rotary drill bit 10.
[0060] FIG. 5 illustrates nozzle 110 directed in an axis coincident
to the central axis of flow port 12, in a manner similar to the
orientation of conventional nozzle assemblies, as illustrated in
FIG. 3. FIG. 6 illustrates nozzle 110 directed in an axis of
maximum angular relation to the central axis of flow port 12. As
seen in this view, the maximum angular relation is predefined by
interference between limiter 146 and extension 114.
[0061] A principal advantage of the present invention is that by
predefining the range of angular orientation of directable nozzles
110, catastrophic failure of rotary drill bit 10 can be avoided.
This is particularly important because nozzles 110 can be easily
assembled on the floor of the drilling rig by persons unfamiliar
with the risk of improper orientation. Another advantage of this
relationship is that retainers 140 can be provided which have
different limiter 146 settings, and whereas retainers 140 are
identified by the angle obtained with extension 114 engaging
limiter 146. This can be used to obtain the specific angular
orientation desired. The desired angle may be determined by
drilling parameters and experimentation. Personnel can then select
a retainer 140 identified to provide the angle, without the need
for special alignment tools and gauges and training on their
use.
[0062] As seen in the preferred embodiment disclosed in FIG. 6,
limiter 146 restricts angular orientation of nozzle 110, and
contains first portal 118 within alignment of flow port 12.
Additional angularity would position first portal 118 of nozzle 110
substantially out of alignment with flow port 12, with flow port 12
substantially blocked by nozzle body 112. This causes at least
three significant problems. First, the turbulence generated would
subject nozzle boss 14 to rapid erosion from the flow of the
drilling fluid. Seals 130 would fail, resulting in retainer 140
erosion, and premature failure of rotary drill bit 10. Retainers
140 are traditionally made of steel, and are quickly eroded if
exposed directly to the drilling fluid flow stream inside rotary
drill bits 10. Second, this configuration effectively reduces the
orifice size of first portal 118, disrupting the designed fluid
dynamics of nozzle 110's design, and causing an increase in the
pressure loss in the system. Third, additional turbulence is
generated by the misalignment of first portal 118 and flow port 12,
causing an increase in the pressure loss in the system. These
second and third affects result in a possible requirement to reduce
the pump speed at the drilling rig floor to manage the pressure in
the system, reducing the system flow rate, and resulting in poor
performance of rotary drill bit 10.
[0063] FIG. 7 is a side-sectional view of an alternative preferred
embodiment of directable nozzle assembly 100. In this embodiment,
nozzle assembly 100 further includes an erosion resistant sleeve
160, designed to prevent erosion from turbulence inside flow port
12 that is unique to directable nozzle assembly 100. Sleeve 160 is
insertable into conventional nozzle boss 14 below nozzle 110.
[0064] As with conventional rotary drill bits previously described,
nozzle boss 14 has a threaded portion 22 for threaded coupling to
retainer 140, and a groove 16 for location of a seal 130, such as
an o-ring seal. This advantageously allows convenient
interchangeability between directable nozzle assembly 100 and
conventional nozzle assembly 200 in rotary drill bit 10.
[0065] As seen in FIG. 6, as nozzle 110 is directably positioned,
first portal 118 increases in proximity to one side of flow port
12, and decreases in proximity to the opposite side of flow port
12. Where first portal 118 is in close alignment with flow port 12,
flow is efficient and turbulence is minimized. Where first portal
118 is not in alignment with flow port 12, a discontinuity in the
flow path exists, and turbulence is generated where drilling fluid
engages nozzle body 112, instead of entering first portal 118. This
results in erosion of flow port 12.
[0066] The above described turbulence will occur even though portal
118 is maintained within flow port 12 by engagement of limiter 146
with extension 114. Over time, the turbulence will subject nozzle
boss 14 to erosion. Seals 130 are therefore at increased risk of
failure, as are retainer 140 and rotary drill bit 10. Sleeve 160
provides an erosion resistant channel that will tolerate the
turbulence generated within flow port 12.
[0067] Referring again to FIG. 7, sleeve 160 has a body portion 170
that extends into flow port 12 beyond first portal 118 of nozzle
110. The outside diameter of body 170 of sleeve 160 fits in close
tolerance or slight interference fit with the inside diameter of
flow port 12. In a more preferred embodiment, a taper 172 is
inscribed on the inside diameter of body 170. Taper 172 permits a
smooth transition for drilling fluid in flow port 12 entering
sleeve 160.
[0068] Sleeve 160 has a collar 162 that engages base 18 of nozzle
boss 14, and resides in groove 16 in place of, or in conjunction
with, o-ring seal 130. As rotary drill bits 10 are normally
inverted for nozzle installation, this configuration allows collar
162 to suspend sleeve 160 in position while nozzle 110 is fitted
into place.
[0069] A nozzle seat 164 is provided on collar 162, providing the
function and benefit of nozzle seat 24 inside nozzle boss 14. In
the preferred embodiment, seat 164 is contoured for complementary
engagement with nozzle body 112. In a more preferred embodiment,
seat 164 forms a spherical segment.
[0070] The geometric orientation of nozzle seat 164 is inverse to
that of compression surface 150. In this configuration, as retainer
140 is progressively threaded into nozzle boss 14 of rotary drill
bit 10, nozzle body 112 is compressed between compression surface
150 of retainer 140 and nozzle seat 164 of sleeve 160. The
compressive force on nozzle body 112 maintains nozzle 110 in place,
while resisting the high outward force generated in nozzle passage
116 by the flow of the drilling fluid. The compressive force on
nozzle body 112 further secures sleeve 160 in place, compressed
between nozzle 110 and base 18.
[0071] In the preferred embodiment, nozzles 100 and sleeves 160 are
made of a hard metal, such as tungsten carbide, or titanium
carbide. The hardness of the hard metal nozzles provides wear
resistance to the abrasive forces associated with the high-velocity
flow of the drilling fluid through the constricted diameter of
nozzles 100, and the turbulence generated in the vicinity of
sleeves 160.
[0072] In the preferred embodiment disclosed in FIG. 7, an
alternative seal configuration is also disclosed. In this
embodiment, a seal 180 is located in bore relief 20 of nozzle boss
14 to prevent drilling fluid from bypassing nozzle 110. In a more
preferred embodiment, seal 180 is a packing seal.
[0073] FIG. 9 discloses another seal configuration for use with
this embodiment. In this embodiment, sleeve 160 further includes a
seal groove 168 for accommodation of a seal 190. In the preferred
embodiment, seal 190 is an o-ring seal. As shown in FIG. 9, another
o-ring seal 130 can be located in groove 16 to seal with collar 162
of sleeve 160. However, the use of seal 190 is also compatible with
the embodiments disclosed in FIGS. 7 and 8, in which seal 180 is
located in bore relief 20.
[0074] FIG. 8 is a side-sectional view of directable nozzle
assembly 100, in which extension 114 of nozzle 110 is significantly
extended. The significant extension of extension 114 is compatible
with all of the disclosed embodiments of the present invention.
[0075] The foregoing detailed description is to be clearly
understood as being given by way of illustration and example, the
spirit and scope of the present invention being limited solely by
the appended claims.
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