Note: Descriptions are shown in the official language in which they were submitted.
CA 02722642 2010-11-17
DRILL PIPE HAVING AN INTERNALLY
COATED ELECTRICAL PATHWAY
This application is divided from Canadian Patent
Application Serial Number 2,494,871 filed October 23, 2002.
FIELD OF THE INVENTION
The present invention relates generally to a drill pipe
for an oil or gas well and more particularly to a drill pipe
having an internally coated conductive material for providing
an electrical pathway for electronic data obtained down hole
to be efficiently transmitted to the surface of an oil or gas
well.
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BACKGROUND OF THE INVENTION
Currently there exist tools in the oil and gas well
industry that are specifically designed to obtain drilling and
geological parameters downhole, near the drill bit. In some
instances, the information obtained by these tools is stored
in memory devices. In such cases, the stored information can
be retrieved when the memory devices are returned to the
surface of the well. This system, however, produces an
undesirable lag time between the initial collection and
storing of the downhole information and the retrieval of the
downhole information at the surface of the well.
As an alternative, the downhole information can be
transmitted to the surface of the well using pressure pulses
in the drilling fluid. However, this method also produces an
undesirable lag time caused by the time a pressure pulse takes
to reach the surface. Accordingly, a need exists for a method
and a system of transmitting data instantaneously and
efficiently to the surface of a well.
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SUMMARY OF THE INVENTION
In one embodiment, the present invention provides a drill
pipe for an oil or gas well comprising: a generally cylindrical
hollow drill pipe having a length; a first conductive coating
connected to the drill pipe to define an electrical pathway that
extends along at least a portion of the length of the drill
pipe; and a second conductive coating connected to the drill
pipe to define a second electrical pathway that extends along at
least a portion of the length of the drill pipe.
The present invention also provides a drill pipe for an oil
or gas well comprising: a generally cylindrical hollow drill
pipe having a length; a conductive coating connected to the
drill pipe to define an electrical pathway that extends along at
least a portion of the length of the drill pipe; and wherein the
conductive coating is connected to an inner diameter of the
drill pipe.
In a further aspect, the present invention provides a
method of communicating to downhole oil or gas well equipment
comprising: providing a generally cylindrical hollow drill pipe
having a length; applying a first conductive coating connected
to the drill pipe to define an electrical pathway that extends
along at least a portion of the length of the drill pipe; and
further applying a second conductive coating on the drill pipe
to define a second electrical pathway that extends along at
least a portion of the length of the drill pipe.
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BRIEF DESCRIPTION OF THE DRAWINGS
These and other features and advantages of the present
invention will be better understood by reference to the
following detailed description when considered in conjunction
with the accompanying drawings wherein:
FIG. 1 is a cross-sectional view of a lower end of a
first drill pipe and a cross-sectional view of an upper end of
a second drill pipe;
FIG. 2 is a cross-sectional view of the drill pipes of
FIG. 1 threadingly connected, wherein each drill pipe has a
conductive coating electrically connected by a connector;
FIG. 3 is a cross-sectional view of the drill pipes of
FIG. 1 threadingly connected, wherein each drill pipe has a
first conductive coating and a second conductive coating, and
wherein the corresponding first conductive coatings and the
corresponding second conductive coatings are electrically
connected by a connector;
FIG. 4A is a longitudinal cross-section of the connector
of FIG. 2;
FIG. 43 is a transverse cross-section of the connector of
FIG. 2, taken from line 4B-4B of FIG. 4A;
FIG. 5 is a cross-sectional view of the drill pipes of
FIG. 1 threadingly connected, wherein each drill pipe has a
conductive coating electrically connected to an upper and a
lower conductive sleeve and wherein a lower conductive sleeve
of the fist drill pipe is connected to the upper conductive
sleeve of the second drill pipe by the connector of FIGs. 4A
and 43; and
FIG. 6 is a cross-sectional view of the drill pipes of
FIG.
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1 1
threadingly connected, wherein each drill pipe has a first
conductive coating electrically connected to a first upper and
a first lower conductive sleeve and a second conductive coating
electrically connected to a second upper and a second lower
conductive sleeve, and wherein the first sleeve and the second
sleeve are electrically connected by a connector.
DETAILED DESCRIPTION OF THE INVENTION
As shown in FIGs. 1-6, the present invention is directed a
drill pipe having an internally coated conductive material for
forming an electrical pathway from an upper end of the drill pipe
to a lower end of the drill pipe. The drill pipe of the current
invention allows for communication between a well head and
downhole equipment in an oil or gas well so that drilling
parameters and geological parameters may be obtained downhole and
transmitted to the well head for analysis.
FIG. 1 shows a lower end 10 of a first drill pipe 12 and an
upper end 14 of a second drill pipe 16. Although omitted for
clarity, the first drill pipe 12 comprises an upper end that is
similar to the upper end 14 of a second drill pipe 16 and the
second drill pipe 16 comprises an lower end that is similar to
the lower end 10 of the first drill pipe 12. As such, reference
to the lower end 10 and the upper end 14 in the following
description is to be understood to apply equally to the first
drill pipe 12 and to the second drill pipe 16. In addition, the
first drill pipe 12 and the second drill pipe 16 are shaped and
formed similarly, such that reference to a drill pipe 22 in the
following description is to be understood to apply equally to the
first drill pipe 12 and to the second drill pipe 16.
As depicted in FIG. 1, the drill pipe 22 comprises a body
portion 20 that is generally cylindrical in shape and has a
hollow center defined by an inner diameter 24. The upper and
lower ends 10 and 14 of the drill pipe 22 each comprise threads
18. The threads 18 allow the upper end 10 of one drill pipe 22
to be connected to the lower end 14 of another drill pipe 22.
Drill pipes 22 that are connected in this way (as is shown in
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1
FIGs. 2-3 and 5-6) are typically collectively referred to as a
drill string 26. Although FIGs. 2-3 and 5-6 show the drill
string 26 as having only two drill pipes 22, the drill string may
comprise any number of connected drill pipes 22.
In an exemplary embodiment, the threads 18 are special
tapered threads that, when engaged, provide a connection that is
almost as strong as the body portion 20 of the drill pipe 22 and
also provides a very reliable pressure seal for drilling fluids
that are pumped through the drill string 26 during the drilling
process.
. In
one embodiment, as depicted in FIG. 2, each drill pipe
22 in the drill string 26 comprises an outer insulative coating
28 attached to the inner diameter 24 of the drill pipe 22, a
conductive coating 30 attached to the outer insulative coating
28, and a inner insulative coating 32 attached to the conductive
coating 30. As such, the outer insulative coating 28, the
conductive coating 30 and the inner insulative coating 32 of each
drill pipe 22 together form an insulated electrical pathway from
the upper end 14 of the drill pipe 22 to the lower end 10 of the
drill pipe 22, i.e. the outer insulative coating 28 insulates the
conductive coating 30 from the body 20 of the drill pipe 22,
which is typically comprised of a metal material, and the inner
insulative coating 32 insulates the conductive coating 30 from
the drilling fluids.
As shown in FIGs. 2-3 and 5-6 when two drill pipes 22 are
connected, a small gap 34 exists between the lower end 10 of one
drill pipe 22 and the upper end 14 of the adjacent drill pipe 22.
In one embodiment, a connector 36 is attached to the drill string
26 in the small gap 34 between adjacent drill pipes 22 to
electrically connect the insulated electrically pathways of the
adjacent drill pipes 22. For example, in the depicted embodiment
of FIG. 2, the connector 36 comprises a protruding section 38
that has a larger diameter than the inner diameter 24 of the
drill pipes 22, such that when the connector 36 is disposed
between the lower end 10 of one drill pipe 22 and .the upper end
14 of the adjacent drill pipe 22 and the drill pipes 22 are
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connected, the connector 36 is trapped in the small gap 34
between the drill pipes 22.
In one embodiment, the protruding section 38 of the
connector 36 comprises a protruding shoulder 40 that mates with
or abuts against a shoulder 42 in the upper end 14 of the drill
pipe 22 to secure the connector to the drill string 26 when the
connector 36 is disposed between the lower end 10 of one drill
pipe 22 and the upper end 14 of the adjacent drill pipe 22.
To establish the electrical connection between the insulated
electrically pathways of the adjacently connected drill pipes 22,
the connector 36 comprises a conducting material 44 that has a
body portion 45, an upper conducting contact 46 and a lower
conducting contact 48. When the connector 36 is disposed between
the lower end 10 of one drill pipe 22 and the upper end 14 of the
adjacent drill pipe 22, the upper conducting contact 46
establishes an electrical connection 50 with the conductive
coating 30 in the lower end 10 of one drill pipe 22 and the lower
conducting contact 48 establishes an electrical connection 52
with the conductive coating 30 in the upper end 14 of the
adjacent drill pipe 22. As such, an electrical pathway is
established from the conductive coating 30 in the lower end 10
of one drill pipe 22, to the upper conducting contact 46, then
to the connector conducting material body portion 45, then to the
lower conducting contact 48, and then to the upper end 14 of the
adjacent drill pipe 22.
In one embodiment, the connector 36 is comprised of an
insulative material, such that the electrical pathway from the
upper conducting contact 46, to the conducing material body
portion 45, to the lower conducting contact 48, is insulated.
For instance, the connector 36 may be formed in a molding
process, such as injection molding, with the conducting material
44 being molded into the insulative material of the connector 36.
In one embodiment, the conducting material 44 is elastic, such
that the upper conducting contact 46 and the lower conducting
contact 48 compress when the electrical connections 50 and 52 are
established between the adjacent drill pipes 22.
CA 02722642 2010-11-17
The connector 36 may also comprise an upper annular groove
54 and a lower annular groove 56. For
instance, in the
embodiment depicted in FIG. 2, the upper annular groove 54 is
disposed above the upper conducting contact 46, and hence above
the electrical connection 50, while the lower annular groove 56
is disposed below the lower conducting contact 48, and hence
below the electrical connection 52. Disposed within each annular
groove 54 and 56 is an elastomeric o-ring 58. The o-ring 58 in
the upper annular groove 54 creates a seal against the conductive
coating 30 in the lower end 10 of one drill pipe 22 to prevent
the drilling fluids from contaminating the electrical connections
50 and 52 from above, while the o-ring 58 in the lower annular
groove 56 creates a seal against the conductive coating 30 in the
upper end 14 of the adjacent drill pipe 22 to prevent the
drilling fluids from contaminating the electrical connections 50
and 52 from below.
The connector 36 may comprise one conducting material 44,
or, as depicted in FIGs. 4A and 4B, the connector 36 may comprise
a plurality of conducting materials 44. For instance, in the
depicted embodiment of FIGs. 4A and 4B, the connector 36
comprises six conducting materials 44, each attached to the
connector 36 and forming the electrical connections 50 and 52 as
described above.
The drill string 26 may comprise a plurality of adjacently
connected drill pipes 22, wherein each adjacently connected drill
pipe 22 has a the connector 36 disposed therebetween as described
above, such that each connector 36 electrically connects the
conductive coating 30 of one drill pipe 22 to the conductive
coating 30 of its adjacent drill pipe 22 to establish an
insulated electrical pathway from an upper end of the drill
string 26 to a lower end of the drill string 26.
As depicted in FIG. 3, each drill pipe 22 in the drill
string 26 may comprise a second conductive coating 60 attached
to the inner insulative coating 32, and a second inner insulative
coating 62 attached to the second conductive coating 60, such
that the inner insulative coating 32, the second conductive
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coating 60 and the second inner insulative coating 62 together
form a second insulated electrical pathway.
In such an embodiment, the connector 36 may have an inwardly
stepped section 63, containing a second conducting material 64
having a body portion 65, an upper conducting contact 66 and a
lower conducting contact 68. The second conducting material 64
may be formed and attached to the conductor 36 as described above
with respect to the conducting material 44.
When the connector 36 is disposed between the lower end 10
of one drill pipe 22 and the upper end 14 of the adjacent drill
pipe 22, the upper conducting contact 66 establishes an
electrical connection 70 with the conductive coating 60 in the
lower end 10 of one drill pipe 22 and the lower conducting
contact 68 establishes an electrical connection 72 with the
conductive coating 60 in the upper end 14 of the adjacent drill
pipe 22. As such, an electrical pathway is established from the
conductive coating 60 in the lower end 10 of one drill pipe 22,
to the upper conducting contact 66, then to the connector
conducting material body portion 65, then to the lower conducting
contact 68, and then to the upper end 14 of the adjacent drill
pipe 22. As described above and as shown in FIGs 4A and 4B, the
connector 36 may comprise one second conducting material 64, or
the connector 36 may comprise a plurality of second conducting
materials 64.
The drill string 26 may comprise a plurality of adjacently
connected drill pipes 22, wherein each adjacently connected drill
pipe 22 has the connector 36 disposed therebetween as described
above, such that each connector 36 electrically connects the
conductive coating 60 of one drill pipe 22 to the conductive
coating 60 of its adjacent drill pipe 22 to establish a second
insulated electrical pathway from an upper end of the drill
string 26 to a lower end of the drill string 26. 0-rings may be
used, as described above, to prevent the drilling fluids from
contaminating the electrical connections 70 and 72.
Each drill pipe 22 in the drill string 26 may comprise a
plurality of conductive coatings and each connector may comprise
CA 02722642 2010-11-17
1 a corresponding plurality of inwardly stepped sections and
conducting materials, such that the drill string 26 comprises a
plurality of insulated electrical pathways from an upper end of
the drill string 26 to a lower end of the drill string 26.
In one embodiment, as depicted in FIG. 5, the lower end 10
and the upper end 14 of each drill pipe 22 in the drill string
26 comprises a lower annular recess 76 and an upper annular
recess 78. In such an embodiment, the outer insulative coating
28 is attached to the inner diameter 24, the upper annular recess
78 and the lower annular recess 76 of each drill pipe 22. An
upper and a lower conducting sleeve 82 and 80 are attached to the
outer insulative coating 28 in the upper annular recess 78 and
the lower annular recess 76, respectively. For instance, the
upper and lower conducting sleeves 82 and 80 may be press fit
into the upper and lower annular recesses 78 and 76,
respectively.
In this embodiment, the conductive coating 30 is attached
to the outer insulative coating 28 and to the upper and lower
conducting sleeves 82 and 80 to establish an electrical pathway
from the upper end 14 to the lower end 10 of each drill pipe 22.
The inner insulative coating 32 is attached to the conductive
coating 30 such that the conductive coating 30 is insulated.
As described above, to establish an electrical connection
between the insulated electrically pathways of the adjacently
connected drill pipes 22, the connector 36 is disposed between
the lower end 10 of one drill pipe 22 and the upper end 14 of the
adjacent drill pipe 22. When so positioned, the upper conducting
contact 46 establishes an electrical connection 90 with the lower
conducting sleeve 80 and the lower conducting contact 48
establishes an electrical connection 92 with the upper conducting
sleeve 82, such that an insulated electrical pathway is
established from the conductive coating 30 in the lower end 10
of one drill pipe 22, to the lower conducting sleeve 80, then to
the upper conducting contact 46, then to the connector conducting
material body portion 45, then to the lower conducting contact
48, then to the upper conducting sleeve 82, and then to the upper
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1 end 14 of the adjacent drill pipe 22.
The conducting sleeves 80 and 82 provide a more robust
contact surface than the conductive coating. Hence the addition
of the conducting sleeves 80 and 82 produces more secure
electrical connection 90 and 92 with the connector 36. 0-rings
may be used, as described above, to prevent the drilling fluids
from contaminating the electrical connections 90 and 92. In
addition, rather than extending the outer insulative coating 28
into the upper and lower annular recesses 78 and 76, the contact
sleeves 82 and 80 may each comprise an insulative material on its
outer surface.
In the embodiment depicted in FIG. 6, each drill pipe 22 in
the drill string 26 comprises a second lower annular recess 86
and a second upper annular recess 88. In this embodiment, a
second lower conducting sleeve 100 and a second upper conducting
sleeve 102 are attached to the second lower annular recess 86 and
the second upper annular recess 88, respectively, such as by
press fitting. The second conductive coating 60 is attached to
the inner insulative coating 32 and to the second upper and lower
conducting sleeves 102 and 100 to establish a second electrical
pathway from the upper end 14 to the lower end 10 of each drill
pipe 22. The second inner insulative coating 62 is attached to
the second conductive coating 60 such that the second conductive
coating 60 is insulated.
In this embodiment, the connector 36 may comprise the
inwardly stepped portion 63 comprising the second conducting
material 64, such that the upper conducting contact 66 and a
lower conducting contact 68 establish electrical contacts 110 and
112, respectively, with the second lower conducting sleeve 100
and the second upper conducting sleeve 112.
Each drill pipe 22 in the drill string 26 may comprise a
plurality of conductive coatings and a plurality of corresponding
upper and lower conducting sleeves; and each connector may
comprise a corresponding plurality of inwardly stepped sections
and conducting materials, such that the drill string 26 comprises
a plurality of insulated electrical pathways from an upper end
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of the drill string 26 to a lower end of the drill string 26.
In each of the embodiments described above, each coating
may have a thickness in the range of approximately .006 inches
to approximately .030 inches. In addition, each insulative
coating may comprise a plastic polymer such as an epoxy,
phenolic, teflon, or nylon. The insulative coatings may be spray
applied. The conductive coatings may comprise a metal material,
such as copper, aluminum, silver or gold, or a mixture of metal
particles and a polymer. The conductive coatings may be applied
by plating or spraying.
The preceding description has been presented with
references to presently preferred embodiments of the invention.
Persons skilled in the art and technology to which this
invention pertains will appreciate that alterations and changes
in the described structures and methods of operation can be
practiced. Specifically, although drill strings having only one
or two conductive pathways are described herein, it should be
understood that the principles of the invention may be applied
to form drill pipe and therefore drill strings having any
arbitrary number of conductive pathways. Accordingly, the
foregoing description should not be read as pertaining only to
the precise structures described and shown in the accompanying
drawings, but rather should be read as consistent with and as
support for the following claims, which are to have their
fullest and fairest scope. The scope of the claims should not be
limited by the preferred embodiments set forth in the examples,
but should be given the broadest interpretation consistent with
the description as a whole.
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