U.S. patent application number 09/793056 was filed with the patent office on 2001-10-18 for auto-extending/retracting electrically isolated conductors in a segmented drill string.
Invention is credited to Chau, Albert W., Mercer, John E..
Application Number | 20010030047 09/793056 |
Document ID | / |
Family ID | 23233085 |
Filed Date | 2001-10-18 |
United States Patent
Application |
20010030047 |
Kind Code |
A1 |
Chau, Albert W. ; et
al. |
October 18, 2001 |
Auto-extending/retracting electrically isolated conductors in a
segmented drill string
Abstract
Arrangements and associated methods are described for providing
an isolated electrically conductive path in a system in which a
boring tool is moved through the ground in a region. The system
includes a drill rig and a drill string which is connected between
a boring tool, or other in-ground device, and the drill. The drill
string is made up of a plurality of electrically conductive drill
pipe sections, each of which includes a section length and all of
which are configured for removable attachment with one another to
facilitate the extension and retraction of the drill string by one
section length at a time. The arrangement associated with each
drill pipe section provides part of at least one electrically
conductive path along the section length of each drill pipe
section, which electrically conductive path is electrically
isolated from its associated drill pipe section and extends from
the boring tool to the drill rig such that the electrically
conductive path is extended by the section length when the drill
string is extended by attachment of an additional drill pipe
section to the drill string at the drill rig and the electrically
conductive path is shortened by the section length when the drill
string is shortened by detaching the additional drill pipe section
from the drill string at the drill rig.
Inventors: |
Chau, Albert W.;
(Woodinville, WA) ; Mercer, John E.; (Kent,
WA) |
Correspondence
Address: |
BOULDER PATENT SERVICE INC
1021 GAPTER ROAD
BOULDER
CO
803032924
|
Family ID: |
23233085 |
Appl. No.: |
09/793056 |
Filed: |
February 26, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09793056 |
Feb 26, 2001 |
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09317308 |
May 24, 1999 |
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6223826 |
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Current U.S.
Class: |
166/378 ;
166/65.1; 166/77.51 |
Current CPC
Class: |
H01R 13/533 20130101;
E21B 47/0232 20200501; E21B 17/003 20130101 |
Class at
Publication: |
166/378 ;
166/65.1; 166/77.51 |
International
Class: |
E21B 029/02 |
Claims
What is claimed is:
1. In a system in which a boring tool is moved through the ground
in a region, said system including a drill rig and a drill string
which is connected between said boring tool and said drill rig and
is configured for extension and/or retraction from said drill rig
such that, when said drill string is extended, the boring tool
moves in a forward direction through the ground and, when the drill
string is retracted, the boring tool moves in a reverse direction
approaching the drill rig, said drill string being made up of a
plurality of electrically conductive drill pipe sections, each of
which includes a section length and all of which are configured for
removable attachment with one another to facilitate the extension
and retraction of the drill string by one section length at a time,
the improvement comprising: an arrangement associated with each
drill pipe section for providing part of at least one electrically
conductive path along the section length of each drill pipe
section, which electrically conductive path is electrically
isolated from its associated drill pipe section and extends from
the boring tool to the drill rig such that the electrically
conductive path is extended by said section length when the drill
string is extended by attachment of an additional drill pipe
section to the drill string at the drill rig and said electrically
conductive path is shortened by said section length when the drill
string is shortened by detaching the additional drill pipe section
from the drill string at the drill rig.
2. The improvement of claim 1 wherein each drill pipe section
includes opposing first and second ends having first and second end
fittings, respectively, such that adjacent drill pipe sections
which form the drill string are attached to one another using one
first end fitting mated with one second end fitting and wherein
said arrangement includes first and second adapters configured for
installation at corresponding opposing ends of each drill pipe
section such that the first and second adapters of adjacent drill
pipe sections mate when the first and second end fittings of
adjacent drill pipe sections are mated to form an electrical
connection as additional drill pipe sections are added to the drill
string in a way which extends said electrically conductive path
along the section length of the additional drill pipe section.
3. The improvement of claim 2 wherein said arrangement further
includes an insulated electrical conductor positioned in said
through hole and in electrical communication with said first and
second adapters such that the electrical conductor forms the part
of said electrically conductive path between the first and second
adapters.
4. The improvement of claim 3 wherein said first and second
adapters each include connector means for attachment to said
insulated electrical conductor.
5. The improvement of claim 4 wherein said attachment means
includes a crimp connection.
6. The improvement of claim 2 wherein said first and second end
fittings include a self aligning configuration which causes
adjacent drill pipe sections to move into an aligned arrangement as
the first end fitting of one of the adjacent drill pipe sections
engages the second end fitting of the other one of the adjacent
drill pipe sections and wherein said first and second adapters of
the adjacent drill pipe sections are configured to engage one
another at a predetermined point when the first and second end
fittings of the adjacent drill pipe sections are partially engaged
and the adjacent drill pipe sections have moved, at least to some
extent, into said aligned arrangement such that engagement of the
first and second end fittings of the adjacent drill pipe sections
serves, at least to some extent, to align the first and second
adapters prior to the first and second adapters engaging one
another to form said electrical connection as the adjacent drill
pipe sections are attached.
7. The improvement of claim 2 wherein said arrangement is
configured such that said electrically conductive path is shortened
by said section length as the drill string is shortened by
separating the first and second adapters which are mated between
the additional drill pipe section and its adjacent drill pipe
section as the additional drill pipe section is detached from the
drill string to break said electrical connection.
8. The improvement of claim 2 wherein each drill pipe section
defines a through hole extending between said opposing ends and
having an opening leading into said through hole at each of said
opposing ends and wherein one of said first or second adapters is
received in said through hole in proximity to the opening defined
at one end of each drill pipe section and the other one of said
first or second adapters is received in said through hole in
proximity to the opening defined at the other end of each drill
pipe section such that the first and second adapters of adjacent
drill pipe sections mate to form said electrical connection when
the first and second end fittings of adjacent drill pipe sections
are mated.
9. The improvement of claim 8 wherein said first end fitting at the
first end of one drill pipe section is a box fitting and said
second end fitting at the other end of the drill pipe section is a
pin fitting and wherein said first adapter installed in the through
hole in proximity to the first end fitting includes a pin
configuration and the second adapter installed in the through hole
in proximity to the second end fitting includes a box
configuration.
10. The improvement of claim 9 wherein the box configuration of
said second adapter defines a contact surface and the pin
configuration of said first adapter includes contact means for
forming an electrical connection with the contact surface as the
first and second ends of adjacent drill pipe sections are attached
to one another.
11. The improvement of claim 10 wherein said contact means includes
at least one contact finger configured for forming said electrical
connection with said contact surface.
12. The improvement of claim 11 wherein said first and second
adapters are configured such that mated first and second adapters,
received in the through holes of a pair of adjacent drill pipe
sections in the drill string, define a through opening between the
through holes of the pair of adjacent drill pipe sections such that
the through holes of the pair of adjacent drill pipe sections are
in communication via the through opening of the mated first and
second adapters and wherein said second adapter is configured
having an inner surface defining a portion of said through opening
and said contact surface is formed on said inner surface such that
said contact finger extends into the portion of the through opening
defined by the second adapter to form said electrical connection
with the contact surface when the first and second adapter are
mated.
13. The improvement of claim 8 wherein said first and second
adapter are affixed in said through hole using an adhesive.
14. The improvement of claim 8 wherein said first and second
adapters each include attachment means and a first or second
adapter body, respectively, said attachment means for holding the
first and second adapter bodies in proximity to the drill pipe
openings.
15. The improvement of claim 14 wherein said attachment means is
selectively connectable with the first and second adapter body such
that the attachment means can be replaced and the first and second
adapter bodies may be used with a different drill pipe section.
16. The improvement of claim 15 wherein said attachment means and
said first and second adapter bodies are configured for threadable
engagement.
17. The improvement of claim 14 wherein the attachment means is
configured to be received by said through hole to hold the first
and second adapters in proximity the drill pipe openings.
18. The improvement of claim 14 wherein said attachment means
includes a barbed arrangement designed to be radially compressed
within said through hole to hold the first and second adapters in
proximity the drill pipe openings.
19. The improvement of claim 18 wherein the drill pipe section at
each opposing end defines an interior thread within the openings
leading into said through hole and said attachment means includes a
threaded arrangement designed to be received by said interior
thread to hold the first and second adapters in proximity to the
drill pipe openings.
20. The improvement of claim 8 wherein said first and second end
fittings include a self aligning configuration which causes
adjacent drill pipe sections to move into an aligned arrangement as
the first end fitting of one of the adjacent drill pipe sections
engages the second end fitting of the other one of the adjacent
drill pipe sections and wherein said first and second adapters of
the adjacent drill pipe sections are configured to engage one
another at a predetermined point when the first and second end
fittings of the adjacent drill pipe sections are partially engaged
and the adjacent drill pipe sections have moved, at least to some
extent, into said aligned arrangement such that engagement of the
first and second end fittings of the adjacent drill pipe sections
serves, at least to some extent, to align the first and second
adapters prior to the first and second adapters engaging one
another to form said electrical connection as the adjacent drill
pipe sections are attached.
21. The improvement of claim 8 wherein said through hole of each
drill pipe section includes an interior surface and an interior
diameter and wherein said first and second adapters include a
locking arrangement having a pre-installation diameter which is
less than the interior diameter of the through hole of the drill
pipe sections such that the first and second adapters are initially
slidably receivable in the through hole and, after the first and
second adapters are positioned at desired locations in said through
hole, said locking arrangement is configured to be expanded
radially against the interior surface of the through hole in a way
which fixes the position of the first or second adapter.
22. The improvement of claim 21 wherein said system is configured
to direct drilling mud from the drill rig to the boring tool
through the drill string using the through holes defined in the
drill pipe sections and wherein said locking arrangement includes
an expandable elastomeric sleeve to lock each adapter in place and
to seal against drilling mud passing between the elastomeric sleeve
and the interior surface of the drill pipe section.
23. The improvement of claim 8 wherein said system is configured to
direct drilling mud from the drill rig to the boring tool through
the drill string using the through holes defined in the drill pipe
sections and wherein said first and second adapters are configured
such that mated first and second adapters, received in the through
holes of a pair of adjacent drill pipe sections in the drill
string, define a through opening between the through holes of the
pair of adjacent drill pipe sections such that the through holes of
the pair of adjacent drill pipe sections are in communication via
the through opening of the mated first and second adapters for the
passage therethrough of said drilling mud.
24. The improvement of claim 8 wherein said first adapter is a box
adapter tube fitting and said second adapter is a pin adapter tube
fitting, the box and pin adapter tube fittings each including a
tubular locking body defining locking edges which cooperate in a
way that maintains circumferential expansion of the locking body to
fix the box and pin adapter tube in position within the through
hole of a respective drill pipe section.
25. The improvement of claim 24 wherein said locking edges are
serrated such that the pin and box adapter tube fittings including
said locking body may be inserted into one of said through holes
with the locking edges disengaged and, thereafter, the locking body
is circumferentially expanded to engage the locking edges with one
another to accomplish a ratcheting action which maintains the
circumferential expansion against the interior surface of the
through hole to fix the locking body in position.
26. The improvement of claim 25 wherein said locking edges extend
partially, circumferentially around the locking body.
27. The improvement of claim 24 wherein said pin and box adapter
tube fittings are integrally formed from tubular stock.
28. The improvement of claim 27 wherein said pin adapter tube
includes a pin head arrangement defining a compression slot such
that certain circumferential forces around the pin head arrangement
will result in the pin head arrangement having a reduced radius and
said box adapter tube fitting includes a box head arrangement
configured to engage the pin head arrangement in a way which
applies force circumferentially around the pin head arrangement to
reduce said diameter so as to insert the pin head arrangement into
the box head arrangement forming electrical contact therewith when
adjacent drill pipe sections are mated.
29. The improvement of claim 24 wherein said pin and box adapter
tube fittings are each inserting into an electrical insulating tube
which is disposed between each pin and box adapter tube fitting and
the interior surface of one of said through holes to provide
electrical isolation of the pin and box adapter tube fittings from
drill pipe sections.
30. The improvement of claim 24 wherein said locking body includes
a length disposed between first and second openings and said
locking edges are defined by a through cut having a predetermined
configuration extending along said length from said first opening
to said second opening.
31. The improvement of claim 1 wherein said arrangement is
configured for providing at least two electrically conductive paths
along the section length of each drill pipe section, which
electrically conductive paths are electrically isolated from the
drill pipe sections and from one another and which extend from the
boring tool to the drill rig such that each electrically conductive
path is extended by said section length when the drill string is
extended by attachment of an additional drill pipe section to the
drill string at the drill rig.
32. The improvement of claim 31 wherein each drill pipe section
includes opposing first and second ends having first and second end
fittings, respectively, such that adjacent drill pipe sections
which form the drill string are attached to one another using one
first end fitting mated with one second end fitting and wherein
said arrangement includes first and second adapters configured for
installation at corresponding opposing ends of each drill pipe
section such that the first and second adapters of adjacent drill
pipe sections mate when the first and second end fittings of
adjacent drill pipe sections are mated to form an electrical
connection corresponding to each electrically conductive path as
additional drill pipe sections are added to the drill string in a
way which extends each electrically conductive path along the
section length of the additional drill pipe section.
33. In a system in which a boring tool is moved through the ground
in a region, said system including a drill rig and a drill string
which is connected between said boring tool and said drill rig and
is configured for extension and/or retraction from said drill rig
such that, when said drill string is extended, the boring tool
moves in a forward direction through the ground and, when the drill
string is retracted, the boring tool moves in a reverse direction
approaching the drill rig, said drill string being made up of a
plurality of drill pipe sections, each of which includes a section
length and all of which are configured for removable attachment
with one another to facilitate the extension and retraction of the
drill string by one section length at a time, in a method of
providing at least one electrically conductive path which is
electrically isolated from the drill pipe sections and which
extends from the boring tool to the drill rig, the improvement
comprising the step of: configuring each drill pipe section such
that said electrically conductive path is extended by one section
length by removably attaching one drill pipe section to an above
ground end of said drill string and said electrically conductive
path is shortened by one section length by detaching said one drill
pipe section from the above ground end of said drill string.
34. In a system in which a boring tool is moved through the ground
in a region, said boring tool including an electronic package, said
system including a drill rig and a drill string which is connected
between said boring tool and said drill rig and is configured for
extension and/or retraction from said drill rig such that, when
said drill string is extended, the boring tool moves in a forward
direction through the ground and, when the drill string is
retracted, the boring tool moves in a reverse direction approaching
the drill rig, said drill string being made up of a plurality of
drill pipe sections each of which includes a conductive pipe body,
each of which includes a section length and all of which are
configured for removable attachment with one another to facilitate
the extension and retraction of the drill string by one section
length at a time, a method of operating said system, said method
comprising the steps of: a) configuring each drill pipe section to
provide at least one electrically conductive path between opposing
ends of each drill pipe section and electrically isolated from said
conductive pipe body; b) attaching one end of an initial drill pipe
section to said boring tool to form an initial portion of the drill
string such that said electrically conductive path of the initial
drill pipe section is in electrical communication with the
electronic package in the boring tool; and c) attaching one of the
opposing ends of a second drill pipe section to the other, above
ground end of the initial drill pipe section in a way which
connects the electrically isolated conductive path of the second
drill pipe section to the electrically isolated conductive path of
the initial drill pipe section to form an overall electrically
isolated conductive path extending between the other, above ground
end of the overall conductive path at the drill rig and the boring
tool.
35. The method of claim 34 including the step of: d) advancing the
boring tool using the drill string made up of the second drill pipe
section and the initial drill pipe section.
36. The method of claim 35 including the step of electrically
energizing said overall isolated electrically conductive path as
the boring tool is advanced.
37. The method of claim 36 wherein said overall isolated
electrically conductive path is electrically energized to provide
electrical power to said electronic package.
38. The method of claim 36 wherein said overall isolated
electrically conductive path is electrically energized to carry a
data signal from said electronic package to the drill rig.
39. The method of claim 35 including the steps of: e) attaching one
of the opposing ends of an additional drill pipe section to the
above ground end of the drill string in a way extends the drill
string and which connects the electrically isolated conductive path
of the additional drill pipe section to the overall isolated
electrically conductive path such that, as the additional drill
pipe section is attached to the drill string, the overall
electrically conductive path is extended by one section length; and
f) further advancing the boring tool using the extended drill
string.
40. The method of claim 39 including the step of successively
repeating steps (e) and (f) until such time that the boring tool
has been advanced by a desired amount.
41. The method of claim 39 including the step of: g) electrically
energizing the overall electrically conductive path as the boring
tool is advanced using the drill string.
42. The method of claim 41 including the step of repeating steps
(e) through (g), in sequence, until such time that the boring tool
has been advanced by a desired amount.
43. In a system in which a boring tool is moved through the ground
in a region using a drill rig, said system including a drill rig
and a drill string which is connected between said boring tool and
said drill rig and is made up of a plurality of drill pipe sections
such that the drill string can be advanced or retracted from said
drill rig to move the boring tool in a forward direction or in a
reverse direction, respectively, through the ground, each drill
pipe section comprising: a) first and second opposing ends and an
elongated body having a length between said opposing ends and
defining a through hole along said length, the opposing ends being
configured for removable attachment with the opposing ends of other
drill pipe sections within the drill string; and b) an arrangement
for providing at least one electrically conductive path along said
length between said opposing ends which electrically conductive
path is electrically isolated from said elongated body and which
arrangement is configured for electrical connection to the
electrically conductive path of another one of the drill pipe
sections such that attaching one of the first or second opposing
ends of a first drill pipe section to the other one of the first or
second opposing ends of a second drill pipe section electrically
interconnects the electrically conductive paths of the first and
second drill pipe sections.
44. The drill pipe section of claim 43 wherein said first and
second opposing ends include first and second end fittings,
respectively, such that adjacent drill pipe sections which form the
drill string are attached to one another using one first end
fitting mated with one second end fitting and wherein said
arrangement includes first and second adapters configured for
installation at corresponding ones of said first and second
opposing ends such that the first and second adapters of adjacent
drill pipe sections mate when the first and second end fittings of
adjacent drill pipe sections are mated to form an electrical
connection as additional drill pipe sections are added to the drill
string in a way which extends said electrically conductive path
along the length of the additional drill pipe section.
45. The drill pipe section of claim 44 wherein said arrangement
further includes an insulated electrical conductor positioned in
said through hole and in electrical communication with said first
and second adapters such that the electrical conductor forms part
of said electrically conductive path between the first and second
adapters associated with each drill pipe section.
46. The drill pipe section of claim 45 wherein said first and
second end fittings include a self aligning configuration which
causes adjacent drill pipe sections to move into an aligned
arrangement as the first end fitting of one of the adjacent drill
pipe sections engages the second end fitting of the other one of
the adjacent drill pipe sections and wherein said first and second
adapters of the adjacent drill pipe sections are configured to
engage one another at a predetermined point when the first and
second end fittings of the adjacent drill pipe sections are
partially engaged and the adjacent drill pipe sections have moved,
at least to some extent, into said aligned arrangement such that
engagement of the first and second end fittings of the adjacent
drill pipe sections serves, at least to some extent, to align the
first and second adapters prior to the first and second adapters
engaging one another to form said electrical connection as the
adjacent drill pipe sections are attached.
47. The drill pipe section of claim 46 wherein an entrance opening
leads into said through hole at each of said opposing ends and
wherein one of said first or second adapters is received in said
through hole in proximity to the opening defined at one end of said
length and the other one of said first or second adapters is
received in said through hole in proximity to the opening defined
at the other end of said length such that the first and second
adapters of adjacent drill pipe sections mate to form said
electrical connection when the first and second end fittings of
adjacent drill pipe sections are mated.
48. The drill pipe section of claim 47 wherein said entrance
opening leading into said through hole at each of said opposing
ends includes a configuration which cooperates with the first and
second adapters to retain the first and second adapters in position
within the through hole.
49. The drill pipe section of claim 48 wherein the configuration of
said entrance opening includes peripheral threads and wherein said
first and second adapters include mating threads configured to
engage said peripheral threads in a way that supports the first and
second adapters in position.
50. The drill pipe section of claim 48 wherein the configuration of
said entrance opening includes an enlarged diameter which is
greater than an overall diameter of the through hole extending
between the entrance opening at opposing ends of the drill pipe
section such that a peripheral shoulder is formed between each
entrance opening and the overall through hole and wherein said
first and second adapters are configured to be received within said
enlarged diameter against said peripheral shoulder.
51. The drill pipe section of claim 47 wherein said first end
fitting at the first end of said length is a box fitting and said
second end fitting at the other end of said length is a pin fitting
and wherein said first adapter installed in the through hole in
proximity to the first end fitting includes a pin configuration and
the second adapter installed in the through hole in proximity to
the second end fitting includes a box configuration.
52. The drill pipe section of claim 47 wherein said first and
second adapters each include attachment means and a first or second
adapter body, respectively, said attachment means for holding the
first and second adapters in proximity to said openings.
53. The drill pipe section of claim 52 wherein said attachment
means is selectively connectable with the first and second adapter
body such that the attachment means can be replaced and the first
and second adapter bodies may be used with a different drill pipe
section.
54. The drill pipe section of claim 52 wherein the attachment means
is configured to be received by said through hole to hold the first
and second adapters in proximity to said openings.
55. The drill pipe section of claim 47 wherein said through hole
along said length is defined by an interior surface and includes an
interior diameter and wherein said first and second adapters
include a locking arrangement having a pre-installation diameter
which is less than the interior diameter of the through hole along
said length such that the first and second adapters are initially
slidably receivable in the through hole and, after the first and
second adapters are positioned at desired locations in said through
hole, said locking arrangement is configured to be expanded
radially against the interior surface of the through hole in a way
which fixes the position of the first or second adapter.
56. The drill pipe section of claim 55 wherein said system is
configured to direct drilling mud from the drill rig to the boring
tool through the drill string using the through hole defined along
said length of each drill pipe section of the drill string and
wherein said locking arrangement includes an expandable elastomeric
sleeve to lock each adapter in place and to seal against drilling
mud passing between each elastomeric sleeve and each interior
surface.
57. The drill pipe section of claim 47 wherein said system is
configured to direct drilling mud from the drill rig to the boring
tool through the drill string using the through hole defined in
each drill pipe section of the drill string and wherein said first
and second adapters are configured such that mated first and second
adapters, received in the through holes of a pair of adjacent drill
pipe sections in the drill string, define a through opening between
the through holes of the pair of adjacent drill pipe sections such
that the through holes of the pair of adjacent drill pipe sections
are in communication via the through opening of the mated first and
second adapters for the passage therethrough of said drilling
mud.
58. The drill pipe section of claim 43 wherein said arrangement is
configured for providing at least two electrically conductive paths
along said length associated with each drill pipe section, which
electrically conductive paths are electrically isolated from each
elongated body and from one another and which extend from the
boring tool to the drill rig such that each electrically conductive
path is extended by said length when the drill string is extended
by attachment of an additional drill pipe section to the drill
string at the drill rig.
59. In a system in which a boring tool is moved through the ground
in a region, said system including a drill rig and a drill string
which is connected between said boring tool and said drill rig and
is configured for extension and/or retraction from said drill rig
such that, when said drill string is extended, the boring tool
moves in a forward direction through the ground and, when the drill
string is retracted, the boring tool moves in a reverse direction
approaching the drill rig, said drill string being made up of a
plurality of electrically conductive drill pipe sections having
opposing first and second ends and a section length therebetween
and all of which are configured for removable attachment with one
another by physically connecting the first end of one drill pipe
section with the second end of another drill pipe section to
facilitate the extension and retraction of the drill string by one
section length at a time, an arrangement for use with each one of
the drill pipe sections, said arrangement comprising: a) opposing
first and second electrically conductive connectors adapted for
connection with the first and second ends, respectively, of an
associated one of said drill pipe sections in an electrically
isolated manner, said first and second electrically conductive
connectors being configured to electrically connect with
cooperating second and first electrically conductive connectors
respectively associated with another one of the drill pipe
sections; and b) an electrically conductive wire extending between
and electrically connected to said first and second electrically
conductive connectors of each drill pipe section so as to provide
an electrically conductive path interconnecting the first and
second connectors and electrically isolated from each drill pipe
section such that physical connection of one drill pipe section
with another drill pipe section forms at least one continuous
electrical path including the electrically conductive wires of the
physically connected drill pipe sections and the first and second
electrically conductive connectors therebetween whereby, when a
series of drill pipe sections are connected together in a drill
string, an overall continuous electrically conductive path is
provided by the cooperation of said arrangement in each of the
connected drill pipe sections which make up the drill string.
60. The arrangement of claim 59 wherein said first and second
opposing ends of each drill pipe section include first and second
end fittings, respectively, such that adjacent drill pipe sections
which form the drill string are attached to one another using one
first end fitting mated with one second end fitting and wherein
said first and second connectors are configured to mate when the
first and second end fittings of adjacent drill pipe sections are
mated to form an electrical connection as part of said continuous
electrical path.
61. The arrangement of claim 60 wherein said first and second end
fittings include a self aligning configuration which causes
adjacent drill pipe sections to move into an aligned arrangement as
the first end fitting of one of the adjacent drill pipe sections
engages the second end fitting of the other one of the adjacent
drill pipe sections and wherein said first and second connectors
associated with the adjacent drill pipe sections are configured to
engage one another at a predetermined point when the first and
second end fittings of the adjacent drill pipe sections are
partially engaged and the adjacent drill pipe sections have moved,
at least to some extent, into said aligned arrangement such that
engagement of the first and second end fittings of the adjacent
drill pipe sections serves, at least to some extent, to align the
first and second connectors prior to the first and second
connectors engaging one another to form said electrical connection
as the adjacent drill pipe sections are attached.
62. The arrangement of claim 60 wherein each drill pipe section
defines a through hole extending between said opposing ends and
having an opening leading into said through hole at each of said
opposing ends and wherein one of said first or second connectors is
received in said through hole in proximity to the opening defined
at one end of said length and the other one of said first or second
connectors is received in said through hole in proximity to the
opening defined at the other end of said length such that the first
and second connectors of adjacent drill pipe sections mate to form
said electrical connection when the first and second end fittings
of the adjacent drill pipe sections are mated.
63. The arrangement of claim 62 wherein said first end fitting at
the first end of said length is a box fitting and said second end
fitting at the other end of said length is a pin fitting and
wherein said first connector installed in the through hole in
proximity to the first end fitting includes a pin configuration and
the second connector installed in the through hole in proximity to
the second end fitting includes a box configuration.
64. The arrangement of claim 62 wherein said first and second
connectors each include attachment means and a first or second
connector body, respectively, said attachment means for holding the
first and second connector bodies in proximity to said
openings.
65. The arrangement of claim 64 wherein said attachment means is
selectively connectable with the first and second connector body
such that the attachment means can be replaced and the first and
second connector bodies may be used with a different drill pipe
section.
66. The arrangement of claim 64 wherein the attachment means is
configured to be received by said through hole to hold the first
and second adapters in proximity to said openings.
67. The arrangement of claim 62 wherein said through hole along
said length is defined by an interior surface and includes an
interior diameter and wherein said first and second connectors
include a locking arrangement having a pre-installation diameter
which is less than the interior diameter of the through hole along
said length such that the first and second connectors are initially
slidably receivable in the through hole and, after the first and
second connectors are positioned at desired locations in said
through hole, said locking arrangement is configured to be expanded
radially against the interior surface of the through hole in a way
which fixes the position of the first or second adapter.
68. The arrangement of claim 67 wherein said system is configured
to direct drilling mud from the drill rig to the boring tool
through the drill string using the through hole defined along said
length of each drill pipe section of the drill string and wherein
said locking arrangement includes an expandable elastomeric sleeve
to lock each connector in place and to seal against drilling mud
passing between each elastomeric sleeve and each interior
surface.
69. The arrangement of claim 62 wherein said system is configured
to direct drilling mud from the drill rig to the boring tool
through the drill string using the through hole defined in each
drill pipe section of the drill string and wherein said first and
second connectors are configured such that mated first and second
connectors, received in the through holes of a pair of adjacent
drill pipe sections in the drill string, define a through opening
between the through holes of the pair of adjacent drill pipe
sections such that the through holes of the pair of adjacent drill
pipe sections are in communication via the through opening of the
mated first and second connectors for the passage therethrough of
said drilling mud.
70. The arrangement of claim 59 configured for providing at least
two continuous electrical paths, which electrically conductive
paths are electrically isolated from each drill pipe section and
from one another and which extend from the boring tool to the drill
rig such that each continuous electrical path is extended by said
section length when the drill string is extended by attachment of
an additional drill pipe section to the drill string at the drill
rig.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates generally to underground
directional boring and more particularly, to automatically
extending and retracting electrically isolated conductors provided
in a segmented drill string. An associated method is also
disclosed.
[0002] Guided horizontal directional drilling techniques are
employed for a number of purposes including, for example, the
trenchless installation of underground utilities such as electric
and telephone cables and water and gas lines. As a further
enhancement, state of the art directional drilling systems include
configurations which permit location and tracking of an underground
boring tool during a directional drilling operation. As will be
seen, the effectiveness of such configurations can be improved by
providing an electrical pathway between a drill rig which operates
the boring tool and the boring tool itself.
[0003] Turning to FIG. 1, a horizontal boring operation is
illustrated being performed using a boring/drilling system
generally indicated by the reference numeral 10. The drilling
operation is performed in a region of ground 12 including an
existing underground utility 14. The surface of the ground is
indicated by reference number 16.
[0004] System 10 includes a drill rig 18 having a carriage 20
received for movement along the length of an opposing pair of rails
22 which are, in turn, mounted on a frame 24. A conventional
arrangement (not shown) is provided for moving carriage 20 along
rails 22. During drilling, carriage 20 pushes a drill string 26
into the ground and, further, is configured for rotating the drill
string while pushing. The drill string is made up of a series of
individual drill string or drill pipe sections 28, each of which
includes any suitable length such as, for example, ten feet.
Therefore, during drilling, drill pipe sections must be added to
the drill string as it is extended or removed from the drill string
as it is retracted. In this regard, drill rig 18 may be configured
for automatically or semi-automatically adding or removing the
drill string sections as needed during the drilling operation.
Underground bending of the drill string enables steering, but has
been exaggerated for illustrative purposes.
[0005] Still referring to FIG. 1, a boring tool 30 includes an
asymmetric face 32 and is attached to the end of drill string 36.
Steering of the boring tool is accomplished by orienting face 32 of
the boring tool (using the drill string) such that the boring tool
is deflected in the desired direction. Boring tool 30 includes a
mono-axial antenna such as a dipole antenna 44 which is driven by a
transmitter 46 so that a magnetic locating signal 48 is emanated
from antenna 44. In one embodiment, power may be supplied to
transmitter 46 from a set of batteries 50 via a power supply 52. In
another embodiment (not shown), to be described in further detail
below, an insulated electrical conductor is installed within the
drill string between the drill rig and the boring tool in order to
carry power to transmitter 46. A control console 54 is provided at
the drill rig for use in controlling and/or monitoring the drilling
operation. The control console includes a display screen 56, an
input device such as a keyboard 58 and a plurality of control
levers 60 which, for example, hydraulically control movement of
carriage 20 along with other relevant functions of drill rig
operation.
[0006] Drill pipe 28 defines a through passage (not shown) for a
number of reasons, including considerations of design,
manufacturing methods, strength, and weight, but also because
typical horizontal directional drilling also requires the use of
some type of drilling fluid (not shown), most commonly a suspension
of the mineral bentonite in water (commonly referred to as
"drilling mud"). Drilling mud, which is generally alkaline, is
emitted under pressure through orifices (not shown) in boring tool
30 after being pumped through the interior passage of drill pipes
28 which make up drill string 26. Drilling mud is typically pumped
using a mud pump and associated equipment (none of which are shown)
that is located on or near drill rig 18. The pressures at which the
drilling mud is pumped can vary widely, with a commonly encountered
range of operation being 100 PSI to 4,000 PSI, depending on the
design and size of the particular drill rig. For proper operation,
pipe connections between drill pipe sections 28 must not only be
sufficiently strong to join the sections against various thrust,
pull and torque forces to which the drill string is subjected, but
they must also form a seal so as to not allow the escape of
drilling mud from these connections which could result in an
unacceptable drop in drilling mud pressure at the orifices of the
boring tool.
[0007] Continuing to refer to FIG. 1, drilling system 10 may
include a portable locator/controller 70 held by an operator 72 for
sensing locating signal 48 in a way which allows the underground
position of boring tool 30 to be identified. Such portable
detectors are described, for example, in U.S. Pat. Nos. 5,155,442,
5,337,002, 5,444,382 and 5,633,589 as issued to Mercer et al, all
of which are incorporated herein by reference. Alternatively, one
or more detectors (not shown) designed for positioning at fixed,
above ground locations may be used, as described in U.S. patent
application Ser. No. 08/835,834, filing date Apr. 16, 1997, which
is commonly assigned with the present application and is
incorporated herein by reference.
[0008] Guided horizontal directional drilling equipment is
typically employed in circumstances where the inaccuracies and lack
of steering capability of non-guided drilling equipment would be
problematic. A typical example is the situation illustrated in FIG.
1 in which the intended drill path requires steering the boring
tool around, in this instance beneath, obstacles such as utility
14. Guided drilling is also important where the intended path is
curved (not shown) or the target destination is more than a short
distance (typically over 50 feet) from the starting point. In the
latter situation, simply aiming a non-guided boring tool at the
target destination from the starting point will seldom result in
maintaining a sufficiently accurate drill path and/or arriving
reasonably close to the target destination.
[0009] While system 10 of FIG. 1 illustrates a "walk-over" type
locating system using a steerable boring tool, it should be
appreciated that "non-walkover" guidance/locating systems (not
shown) are also useful in conjunction with steerable boring tools.
The less commonly used non-walkover systems typically utilize an
instrumentation/sensor package (not shown) located in the boring
tool that is electrically connected directly to console 54 at the
drill rig via the aforementioned insulated electrical conductor
(not shown) located inside the through passage of the drill string.
While batteries 50 may be used in the boring tool to power the
instrumentation/sensor package, the insulated conductor may be used
to supply electrical power to the instrumentation/sensor package,
thus eliminating batteries 50 for reasons which will be seen. At
the same time, data may be transmitted from the
instrumentation/sensor package to console 54 on the insulated
conductor. Data can also be sent to the instrumentation/sensor
package for calibration, signal processing and programming.
[0010] In the instance of both walkover and non-walkover systems,
the objective is to use information obtained from the locating
system as a basis for making corrections and adjustments to the
direction of steerable boring tool 30 in order to drill a bore hole
that follows an intended drill path. Therefore, in most drilling
scenarios, a walkover system is particularly advantageous in since
the origin of the locating signal leads directly to the position of
the boring tool. Typically, the locating signal, in a walkover
system, is also used to transmit to above ground locations encoded
information including the roll and pitch orientation of boring tool
30 along with temperature and battery voltage readings. Battery
powered transmitters often employ one to four replaceable internal
"dry-cell" type batteries as a source for electric power.
[0011] Although internal battery powered transmitters perform
satisfactorily under many conditions, there are a number of
limitations associated with their use, most of which are due to the
relatively low electric power available from dry-cell batteries.
For example, battery life for a self-powered transmitter is
relatively short and, under some circumstances, the exhaustion of
batteries can result in the need to withdraw an entire drill string
for the purpose of replacing batteries in order to complete a drill
run. It should also be appreciated that the low power level
available from dry-cell batteries, from a practical standpoint,
limits the signal strength of locating signal 48. The available
signal strength is of concern in relation to the depth at which the
boring tool may be tracked. That is, the above ground signal
strength of locating signal 48 decays relatively rapidly as depth
increases. The maximum operating depth for reliable receipt of
locating signal 48 using a dry-cell powered transmitter 46 is
limited to approximately 100 feet, depending on the particular
design and characteristics of boring tool transmitter 46 and the
above ground detector(s) used. This distance may decrease in the
presence of passive and active forms of magnetic field
interference, such as metallic objects and stray magnetic signals
from other sources.
[0012] As a result of these limitations, drill head transmitters
for walkover systems have been developed that can be powered by an
above ground external power source via the aforementioned
electrical conductor. That is, the typical electrical conductor for
this external power source is similar to that used with
non-walkover systems, namely a single insulated wire that connects
to the transmitter with the ground return for the electrical
circuit including the metallic housing of boring tool 30, drill
pipe 28 making up the drill string, and drill rig 18. Even in the
case where a locating signal is transmitted from the boring tool,
the electric conductor may be used to send information from boring
tool 30 to the drill rig including, for example, the roll and pitch
orientation of the boring tool, temperature and voltage, using a
variety of data encoding and transmission methods. By using the
insulated electrical conductor, reliable operational depth may be
increased by increasing the output power of transmitter 46 without
concern over depletion of internal battery power. Moreover,
information encoded on the electrical conductor can be received at
the drill rig essentially irrespective of the operating depth of
the boring tool.
[0013] The prior art practice (not shown) for using
externally-powered electronic and electrical devices located in the
boring tool has been to insert a piece of insulated electrical
conducting wire of appropriate length inside each piece of drill
pipe 28 and manually perform a physical splice of the electrical
wire to the wire in the prior section of drill pipe 28 each time an
additional drill pipe section is added to the drill string. The
process typically entails the use of specialized and relatively
expensive crimp-on connectors and various types of heat-shrinkable
tubing or adhesive wrappings that are mechanically secure,
waterproof, and resistant to the chemical and physical properties
of drilling mud. The process of interrupting pipe joining
operations to manually splice the electrical conductor is
labor-intensive and results in significant reductions in drilling
productivity. Care must also be taken by the person performing
splicing to avoid twisting or pinching the electrical wire, and any
failure to properly splice can result in wire breakage and the need
to withdraw the drill string to make repairs. For drill rigs having
the capability of adding/removing drill pipe automatically or
semi-automatically, this otherwise useful time and labor saving
function must be disabled or interrupted to allow a manual splice
of the electric wire. After completing the drill run, a reverse
process of withdrawing the drill string and removing each section
of drill pipe 28 from the ground requires cutting the wire each
time a section of drill pipe is removed, resulting in considerable
waste due to the discard of these once-used electrical wires and
splicing materials.
[0014] The present invention provides a heretofore unseen and
highly advantageous arrangement and associated method which
automatically forms an isolated electrically conductive pathway
between a drill rig and boring tool as the drill string extending
between the drill rig and the boring tool is either extended or
shortened.
SUMMARY OF THE INVENTION
[0015] As will be described in more detail hereinafter, there are
disclosed herein arrangements and an associated method of providing
an isolated electrically conductive path in a system in which a
boring tool is moved through the ground in a region. The system
includes a drill rig and a drill string which is connected between
a boring tool, or other in-ground device, and the drill rig and is
configured for extension and/or retraction from the drill rig such
that, when the drill string is extended, the boring tool moves in a
forward direction through the ground and, when the drill string is
retracted, the boring tool moves in a reverse direction approaching
the drill rig. The drill string is made up of a plurality of
electrically conductive drill pipe sections, each of which includes
a section length and all of which are configured for removable
attachment with one another to facilitate the extension and
retraction of the drill string by one section length at a time. The
improvement comprises an arrangement associated with each drill
pipe section for providing part of at least one electrically
conductive path along the section length of each drill pipe
section, which electrically conductive path is electrically
isolated from its associated drill pipe section and extends from
the boring tool to the drill rig such that the electrically
conductive path is extended by the section length when the drill
string is extended by attachment of an additional drill pipe
section to the drill string at the drill rig and the electrically
conductive path is shortened by the section length when the drill
string is shortened by detaching the additional drill pipe section
from the drill string at the drill rig.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] The present invention may be understood by reference to the
following detailed description taken in conjunction with the
drawings briefly described below.
[0017] FIG. 1 is a diagrammatic elevational view of a drilling
operation being performed in a region in accordance with the prior
art.
[0018] FIG. 2 is a diagrammatic cross-sectional view of adjacent
ends of a pair of drill pipe sections shown here to illustrate a
first embodiment of an arrangement manufactured in accordance with
the present invention for automatically forming a continuous,
isolated electrically conductive path between a drill rig and
in-ground device.
[0019] FIG. 3A is a diagrammatic cross-sectional view of a box
adapter fitting forming part of the arrangement of FIG. 2 shown
here to illustrate details of its construction.
[0020] FIG. 3B is a diagrammatic cross-sectional view of a pin
adapter fitting forming part of the arrangement of FIG. 2 shown
here to illustrate details of its construction and which is
configured to mate with the box adapter fitting of FIG. 3A when the
fittings are installed in adjacent drill pipe sections.
[0021] FIG. 3C is an end view of the pin adapter fitting of FIG. 3B
shown here to illustrate further details of its construction.
[0022] FIG. 4 is a diagrammatic cross-sectional view showing mated,
adjacent ends of the pair of drill pipe sections of FIG. 2
illustrating mated pin and box adapter fittings of FIGS. 3A-3C
which automatically form a continuous, isolated electrically
conductive path in accordance with the present invention.
[0023] FIG. 5 is a diagrammatic partially cut-away view of adjacent
ends of a pair of drill pipe sections shown here to illustrate a
second embodiment of an arrangement manufactured in accordance with
the present invention for automatically forming a continuous,
isolated electrically conductive path between a drill rig and
in-ground device.
[0024] FIG. 6A is a diagrammatic plan view of a box adapter tube
fitting forming part of the arrangement of FIG. 5 shown here to
illustrate details of its construction.
[0025] FIG. 6B is a diagrammatic plan view of a pin adapter tube
fitting forming part of the arrangement of FIG. 5 shown here to
illustrate details of its construction and which is configured to
mate with the box adapter tube fitting of FIG. 6A when the adapter
tube fittings are installed in adjacent drill pipe sections.
[0026] FIG. 6C is an end view of the pin adapter fitting of FIG. 6B
shown here to illustrate further details of its construction.
[0027] FIG. 7 is a diagrammatic cross-sectional view showing mated,
adjacent ends of the pair of drill pipe sections of FIG. 5
illustrating mated pin and box adapter tube fittings according to
FIGS. 6A-6C which automatically form a continuous, isolated
electrically conductive path in accordance with the present
invention.
[0028] FIG. 8 is a diagrammatic cross sectional view of adjacent
ends of the pair of adjacent drill pipe sections shown here to
illustrate a third embodiment of an arrangement manufactured in
accordance with the present invention for automatically forming a
continuous, isolated electrically conductive path between a drill
rig and in-ground device.
[0029] FIG. 9 is a diagrammatic cross sectional view of a tool used
in installing adapter fittings which form part of the embodiment
illustrated in FIG. 8.
[0030] FIG. 10 is diagrammatic cross-sectional view showing mated,
adjacent ends of the pair of drill pipe sections of FIG. 8
illustrating mated pin and box adapter fittings according to the
third embodiment of the invention which automatically form a
continuous, isolated electrically conductive path.
[0031] FIG. 11 is a diagrammatic cross sectional view of adjacent
ends of the pair of adjacent drill pipe sections shown here to
illustrate a fourth third embodiment of an arrangement manufactured
in accordance with the present invention for automatically forming
a continuous, isolated electrically conductive path between a drill
rig and in-ground device.
[0032] FIG. 12 is a diagrammatic cross sectional view of adjacent
ends of the pair of adjacent drill pipe sections shown here to
illustrate a multi-conductor embodiment of an arrangement
manufactured in accordance with the present invention for
automatically forming two continuous, isolated electrically
conductive paths between a drill rig and in-ground device.
DETAILED DESCRIPTION OF THE INVENTION
[0033] Having previously described FIG. 1, attention is immediately
directed to FIG. 2 which illustrates a first embodiment of an
arrangement manufactured in accordance with the present invention
and generally indicated by the reference numeral 100 for
automatically extending and retracting electrically isolated
conductors provided in a segmented drill string. It should be noted
that like reference numbers refer to like components throughout the
various figures. Moreover, dimensions in the figures have been
exaggerated with respect to component sizes and relative spacing
for illustrative purposes.
[0034] Arrangement 100 is configured for use with standard drill
pipe sections such as drill pipe section 28 described above. FIG. 2
illustrates drill pipe sections 28a and 28b having arrangement 100
installed therein. It should be appreciated that arrangement 100
may be provided as an after market kit for installation in
commercially available drill pipe sections which may already be in
service or for installation in new drill pipe sections.
Alternatively, manufacturers may produce new drill pipe sections
having arrangement 100 incorporated therein at the time of
manufacture. Drill pipe sections 28 each define through hole 102,
indicated by the reference numbers 102a and 102b, respectively, for
drill pipe sections 28a and 28b. Through holes 102 include a
diameter D and define an interior surface 103. Drill pipe section
28a includes a threaded pin (male) end fitting 104a while drill
pipe section 28b includes a threaded box (female) end fitting 104b.
As is typical in the prior art, these end fittings are designed to
threadably engage one another, for example, by rotating pin end
fitting 104a of drill pipe section 28a into box end fitting 104b of
drill pipe section 28b during a drilling operation so as to extend
the drill string, as described above with regard to FIG. 1. It
should be appreciated that the configurations of these end fittings
cooperate to produce self alignment as they engage one another, yet
produce a suitably strong connection between the drill pipe
sections once the end fittings are fully engaged with one another.
Moreover, as described with regard to FIG. 1, drilling mud (not
shown) is pumped down the drill string and through holes 102a and
102b. The connection formed between drill pipe sections 28a and 28b
should also prevent the escape of the drilling fluid from the drill
string.
[0035] Referring now to FIGS. 3A and 3B in conjunction with FIG. 2,
arrangement 100 includes a box adapter fitting 108 which preferably
is positioned in through hole 102a of drill pipe section 28a and a
pin adapter fitting 110 which preferably is positioned in through
hole 102b of drill pipe section 28b for reasons to be described
below. FIG. 3A illustrates box adapter fitting 108 while FIG. 3B
illustrates pin adapter fitting 110. While only one pair of end
fittings of adjacent drill pipe sections have been illustrated, it
should be appreciated that each drill pipe section includes
opposing ends having a box end fitting at one end and a pin end
fitting at its other end. Thus, each drill pipe section in an
overall drill string (not shown) receives pin adapter fitting 110
in its box end fitting 104b and box adapter fitting 108 in its pin
end fitting 104. A length of insulated conductor 112 (only
partially shown in FIG. 2) is used to electrically interconnect the
pin and adapter fittings associated with each drill pipe
section.
[0036] Referring primarily to FIG. 3A, box adapter fitting 108
includes a first cylindrically shaped electrically conductive body
114 having a threaded end portion 116, an outwardly projecting
peripheral collar 118, having an outer diameter d1, at its opposing
end defining a step 119 and an outer peripheral surface 120, having
a diameter d2, disposed between peripheral collar 118 and threaded
end portion 116. An electrical connection tab 122 extends outwardly
from an area of peripheral collar 118 for use in electrical
connection with conductor 112 (FIG. 2). The interior surface of
conductive body 114 includes a diameter d3 configured to allow the
passage of drilling fluid and comprises an electrical contact
surface 123. Conductive body 114 may be formed from suitable
electrically conductive materials including, but not limited to
stainless steel or beryllium copper. A cylindrical electrical
insulating sleeve 124 includes a length L and outer diameter D'.
Sleeve 124 includes an inwardly projecting peripheral collar 126
defining an entrance diameter approximately equal to d2. The
remaining extent of length L of sleeve 124 includes an inner
diameter that is slightly greater than d1. Sleeve 124 may be formed
from suitable materials such as, for example, delrin. A compression
collar 130 is captured between peripheral collar 126 of sleeve 124
and a locking ring 132. The latter is designed to threadably engage
threaded end portion 116 of conductive body 114 and is produced
from an electrically non-conductive material such as, for example,
delrin. Alternatively (not shown), locking ring 132 may include a
conductive, threaded inner body surrounded on its exterior by an
electrical insulating material. Compression collar 130 may be
formed from elastomeric materials such as, for example,
polyurethane. Locking ring 132 also includes a pair of opposing
notches 134 (as shown by a dashed line) which may be utilized in
rotating the locking ring relative to conductive body 114. Specific
details regarding the installation and operational use of box
adapter fitting 108 will be provided at an appropriate point
hereinafter following a description of pin adapter fitting 110.
[0037] Turning now to FIG. 3B, pin adapter fitting 110 includes a
second cylindrically shaped electrically conductive body 140 having
threaded end portion 116, peripheral collar 118, including its
outer diameter d1, defining step 119 and outer peripheral surface
120, having a diameter d2, disposed between peripheral collar 118
and threaded end portion 116. Electrical connection tab 122 extends
outwardly from an area of peripheral collar 118. Conductive body
140, like previously described conductive body 114, may be formed
from suitable electrically conductive materials including, but not
limited to beryllium copper and defines a through opening 135 for
the passage of drilling fluid. Installation of cylindrical
electrical insulating sleeve 124, locking collar 130 and locking
ring 132 will be described below.
[0038] Referring to FIGS. 3B and 3C, second conductive body 140
includes a contact finger arrangement 142 formed as an outermost
part of threaded end portion 116. Contact finger arrangement 142
includes an opposing pair of elongated electrical contact fingers
144. Each contact finger includes an elongated contact arm 146 and
an end contact 148. Elongated contact arms 146 are preferably
integrally formed with conductive body 140. End contacts 148 may be
integrally formed with contact arms 146 (not shown) or may be
produced separately and attached by any suitable method (as shown)
such as, for example, welding. Separately produced end contacts may
be formed from suitable electrically conductive materials such as,
for example, stainless steel or high strength copper alloy. FIG. 3C
shows locking ring 132 threadably engaged with second conductive
body 140 using threads 148 of the locking ring and conductive body,
where these threads are indicated diagrammatically by a zigzag
line. It should be noted that the configuration of contact fingers
144 allows the contact fingers to be biased towards one another
such that the contact fingers exert a resilient, outward force
against applied inward biasing forces.
[0039] Referring to FIGS. 2, 3A and 3B, having generally described
the structure of arrangement 100, its installation will now be
described. Each adapter fitting is initially assembled by first
sliding insulating sleeve 124 onto either conductive body 114 of
box adapter fitting 108 or conductive body 140 of pin fitting
adapter 110 such that outwardly projecting peripheral collar 118 is
received against inwardly projecting peripheral collar 126 of
sleeve 124. Compression collar 130 is then positioned on either of
the conductive bodies, as shown. Because compression collar 130 is
generally formed from elastomeric materials, its inner diameter may
be slightly less than d2 so long as the compression collar is
positionable as shown. Following installation of the compression
collar, locking ring 132 is installed with notches 134 exposed for
access thereto.
[0040] Following initial assembly of the adapter fittings,
installation in a drill pipe section may proceed. Outer diameter D'
of box adapter fitting 108 and pin adapter fitting 110 are
configured to be less than diameter D of through hole 102 in one of
drill pipe sections 102. Therefore, the pin and box adapters are
slidably receivable in through hole 102. As illustrated in FIG. 2,
box fitting adapter 108 is preferably installed at pin end fitting
104a of each drill pipe section while pin fitting adapter 110 is
preferably installed at box end fitting 104b of each drill pipe
section for reasons to be described below.
[0041] Installation of the adapters may be performed by first
connecting electrical conductor 112 between connection tabs 122 of
one box fitting adapter 108 and of one pin fitting adapter 110.
Thereafter, for example, pin fitting adapter 110 is inserted,
contact finger arrangement 142 first, into through hole 102 at pin
end fitting 104a of a drill pipe section. Pin fitting adapter 110,
with electrical conductor 112 attached, is allowed to slide in the
through hole until positioned at box end fitting 104b as shown in
FIG. 2. At this point, notches 134 of locking ring 132 the pin
fitting adapter may be engaged using a specifically configured
socket tool (not shown). The locking ring is rotated to compress
compression collar 130 between inwardly projecting peripheral
collar 126 of insulation sleeve 124 and locking ring 124. As the
compression collar is compressed, it expands radially between and
against peripheral surface 120 of conductive body 114 or 140 and
interior surface 102 (FIG. 2) of a drill pipe section 28. The
compression collar is designed to seal against the interior of the
drill pipe in order to achieve a tight and secure fit by this
radial expansion. In addition, compression collar 130 will allow
adapter fittings 108 and 110 to accommodate normal manufacturing
variations in the inside diameter of the drill pipe through hole to
avoid the need for additional precision machining of the drill
pipe. It should be appreciated that use of a threaded engaging
configuration permits the removal and/or replacement of the pin and
box adapter fittings and/or of other components, such as
compression collars 130, by a reverse process and results in a
reusable adapter fitting.
[0042] Following installation of the pin fitting adapter, as
described immediately above, box adapter fitting 108, also
connected to conductor 112, is positioned in pin end fitting 104a
of the drill pipe section and fixed in position in essentially the
same manner as pin adapter fitting 110. It should be appreciated
that this installation technique may be modified in any suitable
manner so long as the illustrated configuration of the adapter
fittings and conductor 112 is achieved in the through hole of the
drill pipe section. For example, box adapter fitting 108 may be
installed first. As another example, conductor 112 may initially be
connected to only the adapter fitting to be installed first and,
after its installation, with the conductor extending through the
drill pipe section, the conductor may be connected to the other
adapter fitting prior to its installation.
[0043] Turning again to FIG. 2, attention is now directed to the
operational use of arrangement 100. FIG. 2 illustrates drill pipe
sections 28a and 28b as these sections are about to be attached
with one another. As can be seen in this figure, pin end fitting
104a of drill pipe section 28a is partially extending within box
end fitting 104b of drill pipe section 28b. In this regard, it
should be appreciated that drill pipe sections 28a and 28b will be
brought into substantial alignment by the box and pin end fittings
prior to pin adapter fitting 110 engaging box adapter fitting 108.
Thus, the possibility of damage to the adapter fittings resulting
from misalignment of the drill pipe sections is greatly reduced.
With regard to avoiding damage to the adapter fittings, it should
be appreciated that installation of pin adapter fitting 110 in box
end fitting 104b of each drill pipe section affords substantial
protection to contact fingers 142 extending outwardly from the
through hole of the drill pipe section. That is, installation of
pin adapter fitting 110 in pin end fitting 104 of the drill pipe
sections (not shown) would cause contact fingers 142 to extrude in
a highly exposed manner from the drill pipe section risking damage
during virtually any handling of the drill pipe section.
[0044] Referring to FIGS. 2 and 4, as attachment of drill pipe
sections 28a and 28b proceeds from the pre-aligned situation of
FIG. 2, pin adapter fitting 110 and box adapter fitting 108 contact
one another at a predetermined point (not shown) when substantial
alignment has already been achieved between drill pipe sections 28a
and 28b. At this predetermined point, contacts 148 of contact
fingers 144 engage electrical contact surface 123 of box adapter
fitting 108. As a result, contact finger arms 146 are resiliently
biased towards one another in a way which maintains electrical
contact between contacts 148 and electrical contact surface 123.
Thus, each time an additional drill pipe section is attached to a
drill string (not shown) electrical contact is formed between the
pin adapter fitting and box adapter fitting, as arranged in the
drill pipe section which defines an above ground end of the drill
string and the end of the additional drill pipe section to be
connected therewith. At the same time, drilling fluid may readily
pass through the central through openings defined by the mated box
and pin adapter fittings in adjacent drill pipe sections. In
accordance with the present invention, arrangement 100 produces an
electrically conductive path between a boring tool and a drill rig
(such as shown in FIG. 1) in an essentially automatic manner.
Arrangement 100 is highly advantageous in this regard since
drilling operations need not be interrupted for purposes of
maintaining an electrical connection with the boring tool.
Therefore, the full advantages attendant to drill rigs configured
for automatically adding drill pipe sections to the drill string
will be realized while still maintaining a continuous, isolated
electrically conductive path between the drill rig and the boring
tool. Moreover, this advantage is realized in retraction of the
drill string as well as in its advancement. That is, removal of a
drill pipe section from the above ground end of the drill string
automatically disconnects arrangement 100 within that drill pipe
section from the overall continuous, electrically conductive path
being maintained between the boring tool and the drill rig.
Arrangement 100 is suitable for any application requiring an
isolated electrical conductive pathway between the drill rig and
the underground end of the drill string. For example, the
arrangement may be used with a boring tool to carry electrical
power from the drill rig to the boring tool and/or carrying data to
and/or from the boring tool. Alternatively, arrangement 100, and
other arrangements described below, are useful in utility pullback
operations during which it may be useful to send data from the
underground end of the drill string to the drill rig. Such
information may comprise, for example, tension monitoring data.
[0045] Referring to FIGS. 3A, 3B and 4, it should be appreciated
that typical drilling fluid (not shown) is pumped down the drill
string and flows in the direction indicated by an arrow 160.
Because the drilling fluid exhibits electrical conductivity, any
direct contact between adapter fittings 108 and the drilling fluid
(which is itself in physical and electrical contact with ground via
the uninsulated interior walls of the drill pipe sections) will
create an electrical pathway to ground and cause loss of power
and/or signal. Hereinafter, this electrical pathway may be referred
to as the drilling fluid ground path. Therefore, insulative,
dielectric coatings (not shown) such as, for example, chromium
oxide should be used on surfaces exposed to the drilling fluid
other than outer faces 150 (see FIG. 3B) of electrical contacts 148
of pin adapter fitting 110 and electrical contact surface 123 (see
FIG. 3A) of box adapter fitting 108. Moreover, extension of
insulator sleeve 124 into the through hole of each drill pipe
section, substantially beyond (not shown) conductive bodies 114 and
140, serves to reduce the drilling fluid ground path.
[0046] Alternatively, pin adapter fitting 110 and tube adapter
fitting 108 may be held in place by a separate, replaceable
single-use barbed fitting 126 which is shown in phantom in FIG. 4.
Barbed fitting 126 may include a threaded end 128 which is designed
to engage pin adapter fitting 110 and tube adapter fitting 108
thereby eliminating the need for locking ring 132, the threads on
the associated conductive bodies and compression sleeve 130. In
this way, the adapter fittings may be removed from one drill pipe
section and threaded onto threaded end of the installed barbed
fitting in another drill pipe section. Alternatively, a broken
barbed fitting may readily be replaced at low cost. The barbed
fitting may be formed from suitable materials such as, for example,
stainless steel. In using a barbed fitting or any other fitting to
be deformably received in a drill pipe through hole, connection tab
122, FIG. 4, should be modified to avoid interference.
Alternatively, conductor 112 may be connected directly to surface
123 of box adapter fitting 108 or to the interior surface of the
pin adapter fitting (neither connection is shown). If barbed
fitting 126 is made from an electrically non-conductive material,
insulating sleeve 124 may also be eliminated. Like insulating
sleeve 124, a non-conductive barbed fitting may extend well into
the drill pipe through hole to reduce the electrical pathway formed
through the drilling fluid between the conductive bodies of the
adapter fittings and ground.
[0047] Attention is now turned to FIG. 5 which illustrates a second
embodiment of an arrangement manufactured in accordance with the
present invention and generally indicated by reference numeral 200
for automatically extending and retracting electrically isolated
conductors provided in a segmented drill string. This figure is a
partial cut away plan view having drill pipe sections 28a and 28b
cut away around arrangement 200 for illustrative purposes.
Likewise, dimensions in the figures have been exaggerated with
respect to component sizes and relative spacing for illustrative
purposes.
[0048] Like previously described arrangement 100, arrangement 200
is configured for use with standard drill pipe sections such as
drill pipe section 28 described above. FIG. 5 illustrates drill
pipe sections 28a and 28b having arrangement 200 installed therein.
Further like arrangement 100, it should be appreciated that
arrangement 200 may be provided as an after market kit for
installation in commercially available drill pipe sections which
may already be in service or for installation in new drill pipe
sections. Alternatively, manufacturers may produce new drill pipe
sections having arrangement 200 incorporated therein at the time of
manufacture.
[0049] Referring now to FIGS. 6A, 6B and 6C in conjunction with
FIG. 5, arrangement 200 includes a box adapter tube fitting 202
which preferably is positioned in through hole 102a of drill pipe
section 28a and a pin adapter tube fitting 204 which preferably is
positioned in through hole 102b of drill pipe section 28b for
reasons to be described below. FIG. 6A illustrates box adapter tube
fitting 202 in detail while FIG. 6B illustrates pin adapter tube
fitting 204 in detail. Even though only one pair of end fittings of
adjacent drill pipe sections have been illustrated, it should be
appreciated that each drill pipe section includes opposing ends
having a box end fitting at one end and a pin end fitting at its
other end. Thus, each drill pipe section in an overall drill string
(not shown) receives pin adapter tube fitting 204 in its box end
fitting 104b and box adapter tube fitting 202 in its pin end
fitting 104a. Insulated conductor 112 (only partially shown in FIG.
5) is used to electrically interconnect the pin and adapter tube
fittings associated with each drill pipe section, as will be
further described.
[0050] First describing pin adapter tube fitting 204 with reference
to FIGS. 6B and 6C, the pin adapter tube fitting includes an
overall cylindrical shape, which is best seen in the end view of
FIG. 6C, having a wall thickness of approximately one-sixteenth of
an inch. Other wall thicknesses are equally useful so long as the
requirements described below are satisfied. In this regard, it
should be appreciated that both the pin and box adapter tubes may
be formed from single pieces of tubing, as will be described.
Alternately, the various portions of the pin and box adapter tubes
to be described can be formed separately (not shown) and
interconnected in any suitable manner such as, for example,
stainless steel. The pin and box adapter tube fittings may be
formed from any suitable material including, but not limited to,
stainless steel or high strength copper alloy.
[0051] Continuing to describe pin adapter tube fitting 204, a
centering ring 206, which is visible in both FIGS. 6B and 6C, a
locking body 208 and a pin head arrangement 210 are provided. An
arcuate shaped electrical connection tab 212 extends outwardly from
centering ring 206 for electrical connection with conductor 112
(FIG. 5). Centering ring 206 and locking body 208 are
interconnected by a first arcuate member 214 extending therebetween
while pin head arrangement 210 is connected with locking body 208
by a second arcuate member 216. When pin adapter tube fitting 204
is formed from an overall single piece of tubing, arcuate members
214 and 216 are integrally formed with those portions of the pin
adapter tube fitting which they serve to interconnect. In
cross-section, arcuate members 214 and 216 appear identical to the
end view of electrical connection tab 212, as illustrated in FIG.
6C. A compression slot 217 is defined by pin head arrangement 210
and second arcuate member 216 such that circumferential forces
around the pin head arrangement will result in a reduced radius.
That is, the circumference of the pin head arrangement,
particularly at its outermost end can be reduced for reasons to be
seen.
[0052] Referring to FIG. 6B, locking body 208 includes a specially
configured locking cut 218 which extends along the entire length of
the locking body and defines two opposing pairs of serrated locking
edges 220. The latter are arranged spaced apart from one another
and extending partially along the circumference of locking body
208. Owing to suitable flexibility of the material from which the
locking body is formed, as well as its thickness, the locking body
may be expanded circumferentially in way which causes serrated
locking edges 220 of each pair of edges to move in opposite
direction directions with respect to one another. During this
movement, the serrated edges of each pair are configured so as to
engage one another, accomplishing a ratcheting action which
maintains circumferential expansion of the locking body.
[0053] Referring to FIGS. 5, 6B and 6C, pin adapter tube fitting
204 includes a diameter D" which is designed to be received in an
overall insulating tube 222 (see FIG. 5) that is, in turn, received
in through hole 102. The pin adapter tube fitting, in combination
with insulating tube 222, includes an outer diameter which is less
than diameter D of through hole 102 of the drill pipe sections.
With serrated edges 220 disengaged, the pin adapter tube fitting
received in insulating tube 222 is slidably receivable in through
hole 102. Insulating tube 222 may be formed from suitable
electrical insulating materials such as, for example, polyurethane
which also exhibit at least a certain degree of deformability, for
reasons which will become evident. During installation, the pin
adapter tube fitting and insulating sleeve are installed within
through hole 102b of drill pipe section 28b such that pin head
fitting 210 extends from the through hole into box end fitting
104b. Thereafter, locking body 208 is circumferentially expanded
against insulating tube 222 to engage locking edges 220 which, in
turn, expands against the interior surface of the through hole and
is captured between locking body 208 and the interior surface of
the through hole. Expansion of locking body 208 to engage serrated
edges 220 may be accomplished, for example, by using a swaging
tool. For reasons to be described, insulating tube 222 should
protrude slightly into box end fitting 104b.
[0054] Referring to FIGS. 5, 6A and 6B, box adapter tube fitting
202 is essentially identical to pin adapter tube fitting 204 with
the exception that pin head arrangement 210 is replaced by a box
head arrangement 224. The latter is cylindrical including outer
diameter D". Thus, as will be further described, pin head
arrangement 210 of the pin adapter tube fitting, through
circumferential compression, may be inserted into box head
arrangement 224 of box adapter tube fitting 202. The latter is
installed in through hole 102b of drill pipe section 28a such that
the outermost end of box head arrangement is generally flush with
the end of pin end fitting 104a. At the same time, insulating tube
222 around box adapter tube fitting 204 should extend slightly from
through hole 102a at pin end fitting 104a, as will be further
described. The box adapter tube fitting and its associated
insulating tube 222 are installed in the same manner as described
previously with regard to pin adapter tube fitting 204 using
locking body 208.
[0055] During operation, with reference primarily taken to FIGS. 5
and 7, pin head fitting 210 of pin adapter tube fitting 204 engages
box head arrangement 224 of box adapter tube fitting 202 at a
predetermined point once box end fitting 104b and pin end fitting
104a have engaged one another and are pre-aligned. As engagement of
the drill pipe sections proceeds, pin head arrangement 210 is
circumferentially compressed by box head arrangement 224 so as to
be inserted within the box head arrangement, forming an electrical
connection therewith. Thus, an electrical pathway is automatically
formed between drill pipe sections as the drill pipe sections are
connected with one another. Like previously described arrangement
100, exposed portions of arrangement 200 which contact drilling mud
may be coated with dielectric materials in order to isolate the
connectors from ground connection via the drilling mud. This
isolation is further enhanced by extending insulating tubes 222
further into the interior of the drill pipe section through holes.
In this regard, insulating tubes 222 associated with the pin and
box adapter tube fitting should extend sufficiently from their
associated through holes such that the ends of the insulating
sleeves are biased against one another as illustrated in FIG. 7. In
this way, electrical conduction to ground is further reduced.
[0056] It should be appreciated that arrangement 200 shares all the
advantages of previously described arrangement 100 with regard to
establishing an isolated electrically conductive path between a
boring tool and drill rig. Moreover, because arrangement 200 may be
produced at low cost from tubular stock, it is designed for a
single use. Locking cut 218 may be cut (not shown), for example,
using a laser with an appropriate shield positioned within the
tubular stock. In fact, both the box and pin adapter tubes may be
cut entirely using a laser.
[0057] FIG. 8 illustrates a third embodiment of an arrangement
manufactured in accordance with the present invention and generally
indicated by reference numeral 300 for automatically extending and
retracting electrically isolated conductors provided in a segmented
drill string. As in previously described embodiments, arrangement
300 is configured for use with standard drill pipe sections such as
drill pipe section 28. FIG. 8 illustrates drill pipe sections 28a
and 28b having arrangement 300 installed therein and with the
adjacent drill pipe sections in partial alignment. Furthermore, it
should be appreciated that arrangement 300 may be provided as an
after market kit for installation in commercially available drill
pipe sections which may already be in service or for installation
in new drill pipe sections.
[0058] Arrangement 300 includes a box adapter fitting 302 which
preferably is positioned in through hole 102a of drill pipe section
28a and a pin adapter fitting 304 which preferably is positioned in
through hole 102b of drill pipe section 28b for reasons described
above with regard to protection of the adapter fittings during
drilling operations. Each drill pipe section in an overall drill
string (not shown) receives pin adapter fitting 304 in its box end
fitting 104b and box adapter fitting 302 in its pin end fitting
104a. Insulated conductor 112 (only partially shown in FIG. 8) is
used to electrically interconnect the pin and adapter fittings
associated with each drill pipe section, as described above.
[0059] In as much as arrangement 300 is similar to arrangement 100
described above, present discussions will be limited primarily to
features of arrangement 300 which differ from those of arrangement
100. These features relate for the most part to the manner in which
the fittings are mounted in the drill pipe section through holes.
Specifically, adapter fittings 302 and 304 each include a
deformable conductive body 306 which, in its undeformed condition,
is initially inserted into the drill pipe through holes and,
thereafter, deformed in a way which squeezes compression sleeve 130
against the interior surface of the drill pipe section through hole
to hold the adapter fittings in position. The deformable conductive
body may be integrally formed (i.e., including contact fingers 144)
from suitable materials such as, for example, stainless steel.
Installation of the adapter fittings into drill pipe sections will
be described below. Another feature incorporated in arrangement 300
is a bellows seal 308 which is attached to pin adapter fitting 304,
for example, by an interference fit. Bellows seal 308 will be
described in further detail at an appropriate point below. For the
moment, it should be noted that the bellows seal feature may be
utilized in any embodiment of the present invention.
[0060] Attention is now directed to FIG. 9 for purposes of
describing the installation of adapter fittings 302 and 304 within
drill pipe sections 28. Specifically, this figure illustrates
installation of pin adapter fitting 304 in drill pipe section 28b.
Installation is facilitated using an installation tool 310.
Initially, pin adapter fitting 304 is assembled and prepared for
installation generally arranged in the manner illustrated, but with
deformable conductive body 306 in an undeformed condition.
Installation tool 310 includes a plug fitting 311 which threadably
engages box end fitting 104b of the drill pipe section. A pulling
arm body 312 of tool 310 extends through plug fitting 311 and
defines opposing, elongated pulling arms 314 having outwardly
extending hook portions 316 at their ends. The pulling arm body is
configured for lateral movement relative to plug fitting 311 by a
threaded arrangement. The pulling arms themselves are configured
such that, in the absence any external forces, hook portions 316
move towards one another (not shown) such that the hook portions
may be inserted into the central through opening of pin adapter
fitting 304 for positioning as illustrated whereby to allow plug
fitting 311 to be threaded into box end fitting 104b. Thereafter, a
T-handle 318 forming part of tool 310 is turned in a way which
engages a ball bearing 320 with locking arms 314 to move the
locking arms radially outwardly such that hook portions 316 are in
position to engage the adapter fitting with lateral movement of the
hook portions. At this point, a locking handle 324, which
threadably engages pulling arm body 312, is turned so as to bias a
washer 326 against plug fitting 311 to move the pulling arm body
and, hence, the hook portions laterally in the direction indicated
by an arrow 328. Sufficient force applied using the locking handle
causes deformable body 306 of the adapter fitting to deform
outwardly against compression sleeve 130, as illustrated, to lock
pin adapter fitting 304 in position. It should be appreciated that
end contacts 148 engage plug fitting 311 as the adapter fitting is
moved in the direction of arrow 322. Therefore, proper lateral
positioning of the adapter fitting is automatically achieved using
tool 310. T-handle 318 is then backed off to disengage ball bearing
320 from locking arms 314 such that tool 310 may be removed from
installed pin adapter fitting 304. Installation of box adapter
fitting 302 is performed in essentially the same manner except that
the configuration of plug fitting 311 is modified (not shown) to
accommodate the use of the tool with pin end fitting 104a of a
drill pipe section and to facilitate automatic positioning of box
adapter fitting 302.
[0061] FIG. 10 illustrates drill pipe sections 28a and 28b mated
and having adapter fittings 302 and 304 installed and mated
therein. It should be appreciated that descriptions above relating
to arrangement 100 are equally applicable to arrangement 300 with
regard to adapter fittings 302 and 304 engaging one another as the
drill pipe sections are joined. Moreover, arrangement 300 shares
all of the advantages described above with regard to arrangement
100. In addition, as the drill pipe sections engage one another,
bellows 308 is compressed between adapter fittings 302 and 304 so
as to lengthen the ground path between the adapter fittings and the
drill pipe sections (via drilling fluid) for purposes described
previously. It should be appreciated that bellows 308 may readily
be used in arrangement 100 described above. Bellows 308 may be
formed from any suitable material including, but not limited to
polyurethane. Mounting of the bellows, as described above, may
advantageously accommodate replacement of the bellows in the event
of damage.
[0062] FIG. 11 illustrates a fourth embodiment of an arrangement
manufactured in accordance with the present invention and generally
indicated by reference numeral 400 for automatically extending and
retracting electrically isolated conductors provided in a segmented
drill string. Once again, arrangement 300 is configured for use
with standard drill pipe sections such as drill pipe section 28.
FIG. 11 illustrates drill pipe sections 28a and 28b having
arrangement 400 installed therein and with adjacent drill pipe
sections in partial alignment. The present embodiment may be
provided as an after market kit for installation in commercially
available drill pipe sections already in field service or for
incorporation by manufacturers producing new drill pipe
sections.
[0063] Arrangement 400 includes a box adapter fitting 402 which
preferably is positioned in through hole 102a of drill pipe section
28a and a pin adapter fitting 404 which preferably is positioned in
through hole 102b of drill pipe section 28b for reasons described
above with regard to protection of the fittings during drilling
operations. Each drill pipe section in an overall drill string (not
shown) receives pin adapter tube fitting 404 in its box end fitting
104b and box adapter tube fitting 402 in its pin end fitting 104a.
Insulated conductor 112 (only partially shown in FIG. 11) is used
to electrically interconnect the pin and adapter tube fittings
associated with each drill pipe section, as described above.
[0064] Because arrangement 400 is similar to arrangements 100 and
300 described above, present discussions will be limited primarily
to features of arrangement 400 which differ from those of
arrangements 100 and 300. Once again, these features relate, for
the most part, to the manner in which the fittings are mounted in
the drill pipe section through holes. Specifically, adapter
fittings 402 and 404 each include a barbed portion 406 defined by
outer peripheral surface 120. Barbed portion 406 engages
compression sleeve 130 in a way which radially forces the
compression sleeve outwardly against the inner surface of each
drill pipe section through hole. It is noted that bellows 308 is
present for purposes described above. The installation process (not
shown) of adapter fittings 402 and 404 in their respective drill
pipe sections may be accomplished, for example, by first inserting
the adapter fitting assembly in a though hole without compression
sleeve 130. Thereafter, the compression sleeve may be inserted such
that compression sleeve 130 is immediately adjacent the opening
leading into the through hole and the remainder of the adapter is
immediately adjacent the compression sleeve but behind the
compression sleeve. Using a tool that is similar to tool 310 of
FIG. 9, but which includes appropriate modifications, adapter
fitting 402 or 406 may then be drawn forward, toward the opening of
the through hole while retaining compression sleeve 130 and bellows
308 in position such that barbed portion 406 engages compression
sleeve 130. The adapter fitting is drawn forward to the extent
required to arrive at the illustrated configuration. For purposes
of brevity, mated drill pipe sections bearing adapter fittings 402
and 406 are not illustrated since these adapter fittings engage in
the manner illustrated in FIG. 4 for arrangement 100 and in FIG. 10
for arrangement 300. It should be appreciated that, arrangement 400
shares all of the advantages described above with regard to
previously described arrangements. An extraction tool can be used
to remove the connection adapters for replacement.
[0065] Attention is now directed to FIG. 12 which illustrates a
multiple conductor arrangement manufactured in accordance with the
present invention and generally indicated by reference numeral 500
for automatically extending and retracting two different (i.e.,
parallel) isolated conductors provided in a segmented drill string.
As in previously described embodiments, arrangement 500 is
configured for use with standard drill pipe sections such as drill
pipe section 28. FIG. 12 illustrates drill pipe sections 28a and
28b having arrangement 500 installed therein and with the adjacent
drill pipe sections attached to one another. Furthermore, it should
be appreciated that arrangement 500 may be provided as an after
market kit for installation in commercially available drill pipe
sections which may already be in service or for installation in new
drill pipe sections.
[0066] Arrangement 500 includes a multi-conductor box adapter
fitting 502 which preferably is positioned in through hole 102a of
drill pipe section 28a and a multi-conductor pin adapter fitting
504 which preferably is positioned in through hole 102b of drill
pipe section 28b for reasons described above with regard to
protection of the adapter fittings during drilling operations. The
two conductive paths established by arrangement 500 will be
referred to as the "inner" and "outer" conductive paths for
descriptive reasons and for purposes of clarity. Adapter fittings
502 and 504 have been named in accordance with the configuration of
the inner conductive path since this configuration will be familiar
to the reader from previous descriptions. Each drill pipe section
in an overall drill string (not shown) receives multi-conductor pin
adapter fitting 504 in its box end fitting 104b and multi-conductor
box adapter fitting 502 in its pin end fitting 104a. Insulated
conductors 112a (only partially shown) are used to electrically
interconnect the components associated with the inner conductive
path while insulated conductor 112b is used to electrically
interconnect the components associated with the outer conductive
path.
[0067] Still referring to FIG. 12, arrangement 500 includes an
insulating sleeve 124a which is similar to previously described
insulating sleeve 124. It is noted that the identification letter
"a" has been appended to the reference number 124 for purposes of
clarity since another similarly configured insulating sleeve is
associated with the inner conductive path. Identification letters
have been appended to reference numbers where appropriate to ensure
clarity. An outer path conductive body 506 engages an inwardly
projecting collar 507a of insulating sleeve 124a using an outwardly
projecting collar 118a. Compression collar 130 is positioned around
outer path conductive body 506 immediately adjacent to insulating
sleeve 124a. Locking ring 132 is threadably engaged with the outer
path conductive body. In this regard, multi-conductor box adapter
fitting 502 is similarly configured using insulating sleeve 124,
compression collar 130 and locking ring 132. It should be
appreciated that installation of adapter fittings 502 and 504
within a drill pipe through hole is accomplished in essentially the
same manner as described previously with regard to arrangement 100
using the locking ring/compression collar configuration.
Arrangement 500 also includes bellows 308 on both the
multi-conductor box and pin adapter fittings for reducing the
drilling fluid ground path. Moreover, dielectric coatings may be
applied to conductive portions of the fittings except, of course,
at electrical contact points. Outer path conductive body 506
defines a through opening which receives an inner path conductive
body 140a and supporting components to be described immediately
hereinafter.
[0068] Continuing to refer to FIG. 12, inner path conductive body
140a is similar in configuration to conductive body 140 in defining
contact fingers 144. Inner path conductive body 140a is received in
outer path conductive body 506 using an inner insulating sleeve
124b having an inwardly projecting collar 507b which engages
outwardly projecting collar 118b formed by the inner path
conductive body. An electrically insulating thread ring 508 bears
both inner and outer threads and may be formed from suitable
materials including, but not limited to delrin. The inner threads
of thread ring 508 are threadably engaged with threads 510 defined
by inner path conductive body 140a so as to bias inner insulating
sleeve 124b against peripheral collar 118b of the inner path
conductive body. Outer threads of thread ring 508 are, in turn,
threadably engaged with inner threads 512 defined by outer path
conductive body 506. An insulating ring 514 bearing only an outer
thread is engaged with the inner thread of outer path conductive
body 506 to minimize contact between the inner path conductive body
and drilling fluid (not shown) whereby to reduce the aforementioned
drilling fluid ground path. Assembly of multi-conductor pin adapter
fitting 504 proceeds by placing inner insulating sleeve 124b onto
inner path conductive body 140a followed by threading on thread
ring 508. This assembly is then threaded into outer path conductive
body 506, as shown. Insulating ring 514 is then passed over contact
fingers 144 and threadably engaged with outer path conductive body
506. Thereafter, outer insulating sleeve 124a is installed,
followed by compression collar 130 and locking ring 132. Bellows
308 may be secured, for example, using an interference fit which
allows for ready replacement of the bellows with operational wear
and tear. Installation of multi-conductor pin adapter fitting 506
in drill pipe through hole 102b is accomplished in the manner
described with regard to arrangement 100, as described above.
Conductors 112a and 112b may be attached, for example, by spot
welding (not shown).
[0069] Having described multi-conductor pin adapter fitting 504, a
description will now be provided of multi-conductor box adapter
fitting 502. The latter includes an outer conductive member 522
that is similar in configuration to conductive body 114 of FIGS. 2
and 3A in that it is configured for receiving insulating sleeve
124, compression collar 130 and locking ring 132 for locking
fitting 502 into position within drill pipe opening 102a. An inner
conductive member 524 is supported within outer conductive member
522 by an electrically insulating sleeve member 526. The latter
extends into drill pipe through hole 102a beyond member 524 in
order to reduce the drilling fluid ground path and defines a lip
526 abutting the inward edge of inner conductive member 524 which
serves to prevent lateral movement of the inner conductive member
into through hole 102a. Inner conductive member 524 may be affixed
within insulating sleeve member 526 to avoid lateral movement in an
opposing direction, for example, by using structural bonding or
interference fitting. Insulating sleeve member 526 further defines
a notch 528 which cooperates with outer conductive member 522 to
prevent relative movement therebetween. Additional components of
fitting 504 include a cylindrical spring 530 and a contact ring 532
which are received within a slot 533 defined between insulating
sleeve member 526 and outer conductive member 522 such that contact
ring 532 is biased in the direction indicated by an arrow 534. A
base loop 535 of spring 530 is attached to outer conductive member
522, for example, by spot welding (not shown) to maintain an
electrical connection therebetween. Spot welding may, in turn, be
used to attach spring 530 to contact ring 532. When adjacent drill
pipe sections are mated, as illustrated, contact ring 532 is
resiliently biased against outer conductive body 506 to maintain
outer path electrical connection between adjacent drill pipe
sections. In an alternative single conductor arrangement, it should
be appreciated that the outer path configuration (i.e., using
contact ring 532, spring 530 and associated components) may
advantageously be utilized in implementing a single, isolated
electrically conductive path between the boring tool and drill
rig.
[0070] Assembly of multi-conductor box end fitting may be performed
by first installing spring 530 and contact ring 532 within outer
conductive member 522 and performing appropriate spot welding.
Insulating sleeve 526 may then be snapped into place using notch
528 as inner conductive member 524 is inserted into and glued
within sleeve 526. Sleeve 124, compression collar 130 and locking
ring 132 may then be installed about the periphery of outer
conductive member 522 followed by bellows 308.
[0071] Operation of arrangement 500 is essentially identical to
that of previously described arrangements 100 and 300 with regard
to the inner conductive path. That is, contact fingers 144 engage
the inner surface of inner conductive member 524 as adjacent drill
pipe sections are mated. Therefore, advantages attendant to
protection of the inner conductive path components during drill
pipe handling and connection are equally applicable. Components
which make up the outer conductive path enjoy similar protection.
Specifically, the configuration used in the outer conductive path,
like that of the inner conductive path, serves to protect its
components while the drill pipe sections are handled and brought
into alignment. As adjacent drill pipe sections are mated, contact
ring 532 engages outer path conductive body 506 to form an
electrical contact therewith only after the adjacent drill pipe
sections are threaded together in substantial alignment.
Thereafter, electrical contact is maintained by spring 530 urging
contact ring 532 toward outer path conductive body 506 such that
the outer paths of adjacent drill pipe sections are automatically
electrically connected as the drill pipe sections are mated.
Considering the overall configuration of arrangement 500, it should
be appreciated that this arrangement is devoid of points at which
accumulation of drilling fluid, once dried out, will affect
subsequent electrical connections from being reliably formed
between both the inner and outer conductive paths of adjacent drill
pipe sections.
[0072] As discussed previously, a single isolated conductive path
may, at once, serve in the transfer of data and for supplying
power. In this regard, it should be appreciated that the dual
conductive path configuration of arrangement 500 is useful for
operation in a "fail-safe" mode in which, for example, the system
may automatically switch from a conductive path which fails or
exhibits instability to the other conductive path. Other
applications of a multiple conductor configuration include, for
example, providing signals and power to multiple electronic modules
and increasing signal bandwidth by separating signal and power
path.
[0073] In other multiple conductive path arrangements (not shown),
a first adapter fitting may be designed to engage electrical
contact surfaces of a second adapter fitting as the first and
second adapters are engaged when adjacent drill pipe sections are
attached to one another. The contact surfaces may be formed on an
inner surface of the first adapter within a through opening defined
for the passage of drilling fluid. When adjacent drill pipe
sections are connected, the contact arrangement of a second adapter
fitting may extend into the first adapter to form an electrical
connection with each contact surface. The contact surfaces may be
arranged in electrically isolated and side by side in a segmented
manner cooperating to circumferentially surround the through
opening in the first adapter. Alternatively, the contact surfaces
may be arranged in an electrically isolated manner as coaxial rings
such that each contact surface extends around the inner surface of
the through opening in the first adapter.
[0074] With regard to production of drill pipe sections in
accordance with the present invention that are configured for
automatically maintaining an electrically isolated electrical
pathway between the boring tool and drill rig, it should be
appreciated that drill pipe sections may be modified during or
after manufacture in a number of different ways (not shown) in
order to accommodate adapter fittings designed to cooperate with
these modifications and manufactured in accordance with the present
invention. For example, the through hole of drill pipe sections may
be threaded immediately adjacent each end of the drill pipe
section. In this way, adapter fittings may be configured with a
mating thread such that the adapter fittings may be installed by
simple threadable engagement in the through openings of drill pipe
sections. As another example, each end of the drill pipe opening
may include a diameter that is enlarged relative to the remainder
of the through opening extending between the ends of the drill pipe
section so as to define a peripheral shoulder surrounding the
entrance to the overall reduced diameter remainder of the through
opening. Adapter fittings manufactured in accordance with the
present invention may be positioned in the enlarged diameter
opening at each end of the drill pipe section received against the
peripheral shoulder. When adjacent drill pipe sections are attached
with one another, adapter fittings therein are "trapped" between
the peripheral shoulders of the respective drill pipe sections.
Such adapter fittings may be retained in the enlarged diameter
using, for example, a suitable adhesive. Moreover, these adapter
fittings, as is the case with all arrangements disclosed herein,
may include arrangements for reducing the drilling fluid ground
path such as an insulating sleeve on each fitting wherein the
insulating sleeves of mated adapter fittings engage one another in
a resilient manner (see, for example, insulating tube 222, FIG. 7
and bellows 308, FIG. 10).
[0075] In that the arrangements and associated methods disclosed
herein may be provided in a variety of different configurations and
modified in an unlimited number of different ways, it should be
understood that the present invention may be embodied in many other
specific forms without departing from the spirit of scope of the
invention. Therefore, the present examples and methods are to be
considered as illustrative and not restrictive, and the invention
is not to be limited to the details given herein, but may be
modified within the scope of the appended claims.
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