Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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FIELD WELDABLE CONNECTIONS
This application is a divisional of application no. 2,591,619, filed
June 29, 2007 which is a divisional of application no. 2,467,313, filed
May 14, 2004.
FIELD OF THE INVENTION
The subject matter of the present invention relates to communication
lines. More specifically, the subject matter of the present invention relates
to an
apparatus and method of protecting and sealing spliced communication lines.
BACKGROUND OF THE INVENTION
Communication lines are used in a wide range of applications in the
oilfield industry. The communication lines transmit monitored data regarding
downhole conditions such as temperature and pressure to surface
instrumentation. The communication lines can also be used to send information
down the well from the surface. Additionally, communication lines may also be
used to electrically power downhole equipment. Communication lines may include
electrical conduits, optical fibers, and other methods for data or power
transmission.
In environments such as those encountered in downhole wells, the
communication lines are exposed to hostile conditions such as elevated
temperatures and pressures. To protect the fragile communication lines from
the
hostile conditions, the communication lines are generally carried within
protective
tubing that provides an environmental seal. Problems arise when the seal must
be broken during assembly, installation and/or repair
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of the communication line. For example, in downhole applications, in order for
the
communication line to be fed through production equipment such as packers, the
line
must be cut and then spliced with the downstream line. Thus, after splicing,
the
communication line must once again be sealed from the harsh environment.
There exists, therefore, a need for an apparatus and method of splicing
communication lines that provides structural integrity and protects the
communication
line from the surrounding environment.
SUMMARY OF THE INVENTION
An embodiment of the present invention provides a downhole connector assembly
for sealingly attaching a first and a second segment of a control line. The
control line has
an outer housing that encapsulates a polymeric secondary housing having a
communication line therein. The connector assembly comprises at least one weld
coupling welded to the outer housing of the first and second segment of the
control line.
At least one reflective sleeve replaces at least a portion of the secondary
housing such
that the reflective sleeve is located between the communication line and the
welds of the
weld coupling.
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Another embodiment of the present invention provides a method comprising:
protecting against air expansion through a weld pool of a weld coupling of a
weld splice
assembly, wherein the protecting comprises: grinding a region of an outer
surface of an outer
housing of a cable, the region after the grinding having a substantially
uniform outside
diameter; and providing an inner diameter for the weld coupling approximate
the outside
diameter of the region of the cable after the grinding to ensure close contact
between the
welded surfaces.
A further embodiment of the present invention provides a method of protecting
against air expansion within the weld pool of the weld coupling of a weld
splice assembly,
comprising: welding the first end of the weld coupling to the outer housing of
the first cable
with a fillet weld; welding the second end of the weld coupling to the second
cable with a butt
weld; and providing a weld penetration depth that prevents the weld pool from
contacting the
expanding air.
A still further embodiment of the present invention provides a method of
protecting against air expansion within the weld pool of the weld coupling of
a weld splice
assembly, comprising: providing compression fitting on the end of the weld
coupling.
An even further embodiment of the present invention provides a method of
protecting against air expansion within the weld pool of the weld coupling of
a weld splice
assembly, comprising: providing a two-piece weld coupling; welding the first
piece of the
weld coupling to the first cable with a fillet weld; welding the second piece
of the weld
coupling to the second cable with a fillet weld; welding the first and second
piece of the weld
coupling together with a butt weld; and providing a weld penetration
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depth that prevents the weld pool from contacting the
expanding air.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a sketch of a communication cable.
Figure 2 is a sketch of a section of cable that
has been prepared for splicing.
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Figure 3 is a sketch of the welded splice assembly.
Figure 4 is a sketch of another embodiment of the welded splice assembly
having
a pressure housing.
Figure 5 is a sketch of another embodiment of the welded splice assembly
having
Figure 6 is a sketch of another embodiment of the welded splice assembly
having
a plurality of weld couplings.
Figure 7 is a sketch of another embodiment of the welded splice assembly
having
a plurality of weld couplings and a pressure housing.
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Figure 8 is a sketch of another embodiment of the welded splice assembly.
Figure 9 is a sketch of another embodiment of the welded splice assembly
having
a plurality of weld couplings.
Figure 10 is a sketch of another embodiment of the welded splice assembly
attached to a tool.
5 Figure 11 is a sketch of a wellbore completion including a spliced
communication
line.
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Figure 12 provides a sketch of the welded splice assembly used for a hydraulic
or
fluid conduit.
Figure 13 provides a sketch of another embodiment of the welded splice
assembly
of the present invention having a reflective shield.
Figure 14 provides a sketch illustrating another embodiment of the welded
splice
assembly of the present invention.
Figure 15 provides a sketch of yet another embodiment of the welded splice
assembly of the present invention.
Figure 16 provides a sketch of still another embodiment of the welded splice
assembly of the present invention.
Figure 17 provides a sketch of still another embodiment of the welded splice
assembly of the present invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
In the following detailed description of the subject matter of the present
invention,
the apparatus and method of splicing communication lines is principally
described with
reference to downhole well applications. Such description is intended for
illustration
purposes only and is not intended to limit the scope of the present invention.
In addition
to downhole well applications, the present invention can be used with any
number of
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applications such as pipeline monitoring, subsea well monitoring, and data
transmission,
for example. Furtheiniore, the communication lines may comprise electrical
wiring,
which may facilitate transfer of information, power, or both. All such types
of
communication line splicing are intended to fall within the purview of the
present
invention. However, for purposes of illustration, the present invention will
be principally
described as being used in downhole well applications. Further as used herein,
the term
communication line shall refer to those lines comprising electrical lines or
fiber optic
lines, as well as lines including combinations thereof or combinations with
other types of
lines.
Figure 1 provides a sketch of a typical cable 1 useful in the present
invention. The
cable 1 comprises an outer housing 5, a secondary housing 10, and one or more
communication lines 15. The outer housing 5 provides the structural integrity
for the
cable 1 and protects the communication lines 15 from the surrounding
environment.
Further, the outer housing 5 provides structural protection for the
communication lines 15
from damage caused by the cable 1 impacting, or being impacted by, nearby
tools and
equipment. In one embodiment, the outer housing 5 is comprised of a metallic
material
such as steel, or other metallic alloys, for example. The secondary housing 10
resides
within the outer housing 5 and provides protection for the communication lines
15
contained within. In one embodiment, shown in Fig. 1, the secondary housing 10
is made
from a polymeric material.
Figure 2 provides a sketch of a segment of cable that has been prepared for
splicing. The cable 1 has been cut so that the communication line 15 extends
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longitudinally beyond the outer housing 5 and the secondary housing 10.
Afterwards, a
portion of the secondary housing 10 is removed in order to create a void 20,
which Is
defined by the outer housing 5 and the secondary housing 10.
Figure 3 provides a sketch illustrating the communication line splice of the
present invention. In Fig. 3, the two communication lines being spliced are
designated
15a and 15b. Once the cables la, lb have been prepared for splicing, theimal
insulators
25a, 25b are inserted into the void 20 (shown in Fig. 2) so that the
insulators 25a, 25b lie
between the outer housing 5 and the communication lines 15a, 25b. The
insulators 25a,
25b protect the communication lines 15a, 15b from the heat of the welding.
Additionally,
the insulators 25a, 25b prevent the secondary housing from melting and
outgassing,
which can result in poor weld quality. Prior to splicing, a weld coupling 35
is slid over
one of the cables la, lb. The cleaved communication lines 15a, 15b are then
spliced
together by conventional techniques, such that the communication lines 15a,
15b are
operatively connected at the splice 30. The weld coupling 35 is then slid to
cover the ends
of both cables la, lb, and the weld coupling 35 is secured in place by welds
40. In one
embodiment the welds 40 are foimed using an orbital welder. Once welded, the
weld
coupling 35 protects the splice 30 from corrosion, erosion, and physical
damage resulting
from environmental and operational conditions. Additional protection is
provided against
hydrocarbon darkening resulting from contact with conductive fluid.
Figure 4 provides a sketch of another embodiment of the weld assembly. In this
embodiment, a pressure housing 45 fits over the weld coupling 35. The pressure
housing
45 is slid over the same cable la, lb as the weld coupling 35, but is slid
prior to the
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sliding of the weld coupling 35. After splicing and after the weld coupling 35
is secured
in place, the pressure housing 45 is attached to the cables la, lb such that
the weld
coupling 35 is isolated from environmental conditions. For example the housing
may be
attached by welding, ferrules, or elastomeric seals, among other means. A port
50,
located in the pressure housing 45 enables pressure testing of the welded
assembly.
Figure 5 provides a sketch of another embodiment of the weld assembly. In this
embodiment a gel or epoxy material is pumped through the port into a cavity 52
defined
by the pressure housing 45, the cables la, lb, and the weld coupling 35. This
fluid is used
for pressure testing. The fluid is pumped into the cavity 52 at a high
pressure, and the
welded splice assembly is monitored for signs of failure. After pumping, the
port 50 is
plugged to seal in the viscous fluid. When the spliced section of cable is
installed
downhole, the viscous fluid cures and hardens due to the high downhole
temperatures.
The cured material thus provides additional protection for the splice 30
against erosion,
corrosion, and other environmental conditions.
Figure 6 provides a sketch of another embodiment of the weld assembly having a
plurality of weld couplings 35a, 35b. The embodiment shown in Figure 6 shows
two
couplings, but any number can be used and remain within the purview of the
invention.
The first weld coupling 35a is slid over the first cable la and the second
weld coupling
35b is slid over the second cable lb. An additional thermal insulator 25c is
inserted to
protect the splice 30 at the housing junction 55. After the cables la, lb are
spliced, the
first weld coupling 35a is welded to the first cable la and the second weld
coupling 35b
is welded to the second cable lb. The first weld coupling 35a is then welded
to the
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second weld coupling 35b at the housing junction 55, thereby enclosing the
splice 30. In
this manner, both welds near the secondary housing 10 are formed prior to the
weld
couplings 35a, 35b being sealed to the surrounding environment. Thus, any
resulting
outgassing of the secondary housing 10 is able to escape to the environment
and does not
affect the weld quality.
Figure 7 provides a sketch of another embodiment of the weld assembly. In this
embodiment, the pressure housing 45 protects the two weld couplings 35a, 35b
against
erosion and other damaging environmental conditions. The pressure housing 45,
through
its port 50, enables testing of the welded connections with a standard fluid
for pressure
testing, such as hydraulic oil, or by a different viscous fluid, such as a gel
or epoxy
material.
Figure 8 provides a sketch of another embodiment of the pressure housing 45.
In
this embodiment, the pressure housing 45 is attached to the cables la, lb by
means of
fittings 60a, 60b. The first fitting 60a and the pressure housing 45 are slid
over the first
cable la. The second fitting 60b is slid over the second cable lb. After
splicing, the
fittings 60a, 60b and the pressure housing 45 are positioned such that the
weld coupling
35 is contained within the pressure housing 45. The fittings 60a, 60b are then
tightened,
thereby sealing the welded connections inside the pressure housing 45. The
fittings 60a,
60b in this embodiment seal to the cables la, lb through a dual ferrule
systems 65a, 65b.
The fittings 60a, 60b seal onto the pressure housing 45 by means of an
elastomeric seals
70a, 70b. These sealing mechanisms 65a, 65b, 70a, 70b are not the only means
by which
the seals can be made. All mechanisms by which one could sealingly join the
pressure
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housing 45 and the cables la, lb are intended to fall within the purview of
the present
invention.
Figure 9 provides a sketch of another embodiment of the splice assembly_ In
this
embodiment, the fittings 60a, 60b are connected to pressure housing 45 by
means of a
sealing pipe threads 62b, 62c. A removable port 75 is used to pressure test
the welded
splice assembly.
Figure 10 provides a sketch of another embodiment of the splice assembly. In
this
embodiment, communication line 15 is spliced to a downhole tool 80. The weld
coupling
35 is welded to the outer housing 5 on one side and a section of the tool 80
on the
opposite side.
Figure 11 provides a sketch of a wellbore completion including a spliced
communication line. The cable 1 is installed downhole to communicate with or
power a
piece of downhole equipment 85. The equipment 85 may be controlled by a
controller
located at the surface.
Figure 12 provides a sketch of the welded splice assembly used for a hydraulic
or
fluid conduit. In Fig. 12, a weld coupling 35 is secured over the spliced
hydraulic or fluid
conduits 100a,100b by welds 40. Once welded, the resulting spliced hydraulic
or fluid
line can be pressure tested prior to placement downhole.
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Another embodiment of the welded splice assembly of the present invention is
described with reference to Figure 13 that provides a partial sketch of a
segment of cable
1 that has been prepared for splicing. In this embodiment, a small reflective
sleeve 110 is
inserted into the void 20 between the communication line 15 and the outer
housing 5. The
The reflective sleeve 110 and the communication line 15 are centered inside
the
outer housing 5 with the use of centralizers 112. By using the centralizers
112, a
substantially unifolin air gap 114 is created that provides insulation around
the
The communication line 15 is spliced and the weld coupling 35 is welded to the
outer housing 5 of the cable 1 using a welding electrode 42, as described with
previous
During the welding process, the reflective sleeve 110 protects the insulation
16
and conductor 17 of the communication line 15 from the heat of the welding.
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of the communication line 15 from thermal radiation, which can be the primary
means of
heat transfer at extreme high temperatures.
A pressure housing, as detailed in earlier described embodiments (e.g., Figs.
4, 5,
7, 8, and 9) can be provided for pressure testing the splice assembly and for
isolating the
weld coupling from. environmental conditions.
Figure 14 provides an illustrative sketch of an embodiment of the welded
splice
assembly of the present invention that provides a method adapted to protect
the welded
splice assembly against problems associated with having air trapped within the
weld
coupling 35. As discussed above, after the splice 30 is made, the weld
coupling 35 is slid
over the connection and welded to the outer housing 5 of the cable 1. During
the welding
of the first end of the weld coupling 35, the opposite end of the weld
coupling 35 is open
and thus provides a means for equalization of air pressures. However, during
the welding
of the second end of the weld coupling 35, problems associated with trapped
air can arise.
For example, as the electrode 42 moves into the last part of the cross-section
of the weld
coupling 35 and attempts to trap the air, the expansion of the air caused by
the continuous
addition of heat can cause a hole to be formed in the weld pool.
As shown in Figure 14, a grinding or honing wheel 116 is provided to uniformly
remove material off of the surface of the outer housing 5 of the cable 1. The
resulting
cable 1 has a circular cross-section in which the outer housing 5 has a
substantially
uniforin outside diameter. Thus, a tighter fit with a smaller inner diameter
weld coupling
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35 can be achieved. By having very close contact between the two welded
surfaces, the
expansion of air through the last part of the weld pool can be prevented.
Figure 15 provides an illustrative sketch of another embodiment of the welded
splice assembly of the present invention adapted to protect the welded splice
assembly
against problems associated with having air trapped within the weld coupling
35. In this
embodiment, after welding the first end of the weld coupling 35 to the outer
housing 5 of
the first cable la with a fillet weld 40, the second end of the weld coupling
35 is welded
to the outer housing 5b of the second cable lb with a butt weld 44.
At the butt weld 44, the two faces of the weld 44 can have a very tight fit.
Provided the weld penetration is not too deep, the molten weld pool can be
prevented
from contacting the expanding air and causing a defect. The butt weld 44 can
be
perfoiated using facing tools that are commonly used for butt welding
hydraulic tubing
but specially adapted to accommodate and protect the communication line 15
during the
metal removal operation.
Figure 16 provides an illustration of another embodiment of the welded splice
assembly of the present invention adapted to protect the welded splice
assembly against
problems associated with having air trapped within the weld coupling 35. In
this
embodiment, compression fittings such as ferrules 118 are used on the end of
the weld
coupling 35. The ferrules 118 can be of the type used to create metal-metal
seals on small
diameter tubing, for example.
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The ferrules 118 are swaged onto the end of the weld coupling 35, creating a
metal-metal seal between the weld coupling 35 and the ferrules 118 and between
the
ferrules 118 and the outer housing 5 of the cable 1. The swaging nut 120 is
built split to
be removable from the cable 1 after swaging. Provided the weld electrode is
properly
positioned, the entrapped air is isolated from the weld pool 122 by the metal-
metal seal,
preventing the forming of defects. As before, only the second end of the weld
coupling
35 needs to use the ferrules prior to welding.
Figure 17 provides an illustrative sketch of yet another embodiment of the
welded
splice assembly of the present invention adapted to protect the welded splice
assembly
against problems associated with having air trapped within the weld coupling
35. In this
embodiment, a two-piece weld coupling 35 is used. The two ends of the two-
piece weld
coupling 35 are first welded to the cables la, lb with fillet welds 40.
Because the other
end of each half of the two-piece weld coupling 35 is open, no air entrapment
Occurs
during application of the fillet welds 40.
The two halves of the weld coupling 35 are then welded together using a butt
weld 44. The two faces of the halves of the two-piece weld coupling 35 have
the required
finish and geometry to prevent air escape during the welding process. The weld
penetration is selected to be less than full to prevent the weld pool 122 from
coming in
contact with the expanding air. The wall of the weld coupling 35 and the
resultant
penetration are designed so that the resultant assembly has the required
collapse strength.
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It should be noted that the above embodiments described with reference to
Figures 14 through 17 can be used to advantage with any of the earlier
described
embodiments of the welded splice assembly. The methods and apparatus used to
protect
against problems associated with having air trapped within the weld coupling
35 can be
used to advantage in embodiments employing thermal insulators or reflective
sleeves.
The invention being thus described, it will be obvious that the same may be
varied
in many ways. Such variations are not to be regarded as a departure from the
scope of the invention, and all such are intended to be included within the
scope of the
following non-limiting claims:
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