Note: Descriptions are shown in the official language in which they were submitted.
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COILED TUBING CONNECTOR
STATEMENT REGARDING FEDERALLY SPONSORED
RESEARCH OR DEVELOPMENT
Not Applicable.
FIELD OF THE INVENTION
The present invention relates generally to devices used to connect lengths of
coiled
tubing and more particularly to devices used to connect lengths of composite
coiled tubing.
Another feature of the present invention relates to providing a mechanical
connection of
sufficient strength so that forces of tension, compression, and torque can be
transferred from
one length of tubing to the other through the connector. Further the
connection between
lengths of tubing is hydraulically sealed so as to separate fluids conducted
inside the tubing
arid the connector from any fluids on the outside of the tubing and connector.
The connector
also permits the fluids inside a length of tubing to flow through the
connector on to the
sequential length of tubing. The connector of the present invention also
provides a
mechanism that permits the lengths of tubing to be connected without imparting
any rotation
on either length of tubing. Additionally, the invention relates to connectors
that will also
allow an electrical connection from the joining of electrical wires, or other
types of signaling
cables, embedded within each mufti-conductor pair of tubing to be joined. The
electrical
connection provides seals and insulation that insulates both wire-to-wire and
wire-to-fluid.
BACKGROUND OF THE INVENTION
Coiled tubing, as currently deployed in the oilfield industry, generally
includes small
diameter cylindrical tubing having a relatively thin wall made of metal or
composite material.
Coiled tubing is typically much more flexible and of lighter weight than
conventional drill
pipe. These characteristics of coiled tubing have led to its use in various
well operations. For
example, coiled tubing is routinely utilized to inject gas or other fluids
into the well bore,
inflate or activate bridges and packers, transport well logging tools
downhole, perform
remedial cementing and clean-out operations in the well bore, and to deliver
or retrieve
drilling tools downhole. The flexible, lightweight nature of coiled tubing
malces it
particularly useful in deviated well bores.
Typically, coiled tubing is introduced into the oil or gas well bore through
wellhead
control equipment. A conventional handling system for coiled tubing can
include a reel
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assembly, a gooseneclc, and a tubing injector head. The reel assembly includes
a rotating reel
for storing coiled tubing, a cradle for supporting the reel, a drive motor,
and a rotary
coupling. During operation, the tubing injector head draws coiled tubing
stored on the reel
and injects the coiled tubing into a wellhead. The drive motor rotates the
reel to pay out the
coiled tubing and the gooseneclc directs the coil tubing into the injector
head. A rotary
coupling provides an interface between the reel assembly and a fluid line from
a pump.
Fluids are often pumped through the coiled tubing during operations. Such
arrangements and
equipment for coiled tubing are well known in the art.
While prior art coiled tubing handling systems are satisfactory fox coiled
tubing made
of metal such as steel, these systems do not accommodate the relatively long
spans or drill
string lengths achievable with coiled tubing made of composites. Such extended
spans of
composite coiled tubing strings are possible because composite coiled tubing
is significantly
lighter than steel coiled tubing. In fact, composite coiled tubing can be
manufactured t~ have
neutral buoyancy in drilling mud. With composite coiled tubing effectively
floating in the
drilling mud, downhole tools, such as tractors, need only overcome frictional
forces in order
to tow the composite coiled tubing through a well bore. This characteristic of
composites
markedly increases the operational reach of composite coiled tubing. Thus,
composite coiled
tubing may well allow well completions to depths of 20,000 feet or more,
depths previously
not easily achieved by other methods.
2o Moreover, composite coiled tubing is highly resistant to fatigue failure
caused by
"bending events," a mode of failure that is often a concern with steel coiled
tubing. At least
three bending events may occur before newly manufactured coiled tubing enters
a well bore:
unbending when the coiled tubing is first unspooled from the reel, bending
when travelling
over a gooseneck, and unbending upon entry into an injector. Such accumulation
of bending
events can seriously undermine the integrity of steel coiled tubing and pose a
threat to
personnel and rig operations. Accordingly, steel coiled tubing is usually
retired from service
after only a few trips into a well bore. However, composite coiled tubing is
largely
unaffected by such bending events and can remain in service for a much longer
period of
time.
Hence, systems utilizing composite coiled tubing can be safely and cost-
effectively
used to drill and explore deeper and longer wells than previously possible
with conventional
drilling systems. Moreover, completed but unproductive wells may be reworked
to improve
hydrocarbon recovery. Thus, composite coiled tubing systems can allow drilling
operations
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into formations that have been inaccessible in the past and thereby further
maximize
recovery of fossil fuels.
However, these dramatic improvements in drilling operations cannot be realized
without handling systems that can efficiently and cost-effectively deploy
extended lengths of
composite coiled tubing. Prior art coiled tubing handling systems do not
readily
accommodate the reel change-outs needed when injecting thousands of feet of
coiled tubing
downhole. Prior art coiled tubing handling systems require a work stoppage to
change out an
empty reel for a full reel.. Because such a procedure is inefficient, there is
a need for a coiled
tubing handling system that more efficiently changes out successive reels of
coiled tubing.
to Composite coiled tubing offers the potential to exceed the performance
limitations of
isotropic metals, thereby increasing the service life of the pipe and
extending operational
parameters. Composite coiled tubing is constructed as a continuous tube
fabricated generally
from non-metallic materials to provide high body strength and wear resistance.
This tubing
can be tailored to exhibit unique characteristics which optimally address
burst and collapse
pressures, pull and compression loads, as well as high strains imposed by
bending. This
enabling capability expands the performance parameters beyond the physical
limitations of
steel or alternative isotropic material tubulars. In addition, the fibers and
resins used in
composite coiled tubing construction make the tube impervious to corrosion and
resistant to
chemicals used in treatment of oil and gas wells.
High performance composite structures are generally constructed as a buildup
of
laminant layers with the fibers in each layer oriented in a particular
direction or directions.
These fibers are normally locked into a preferred orientation by a surrounding
matrix
material. The matrix material, normally much weaker than the fibers, serves
the role of
transferring load into the fibers. Fibers having a high potential for
application in constructing
composite pipe include glass, carbon, and aramid. Epoxy or thermoplastic
resins are good
candidates for the matrix material.
In current practice coiled tubing is often used in conjunction with a bottom
hole
assembly connected to the end of the tubing string. The bottom hole assembly
may include a
variety of downhole tools and devices including sensors, orientation devices,
motors,
3o hydraulic rams, and steering tools. If the tubing is supporting a bottom
hole assembly for
drilling, the bottom hole assembly will include a drill bit and other drilling
equipment.
Sensors and monitoring equipment of other binds may be located upstream of the
drill bit.
One consequence of the variety of equipment used in conjunction with coiled
tubing string is
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the need for some means to conduct electrical power and signals from one end
of the string to
the other. In this way power and signals from the control/operating point on
the surface can
be sent to the bottom hole assembly at the opposite end of the string, and
likewise signals
from the bottom hole assembly can be transmitted to the surface. Thus
composite coiled
tubing may be manufactured with conductors embedded in the wall of the tubing
itself. The
conductors may be electrical wires, optical transmitting cables, or other
forms of cabling that
permit the transmission of energy or data. Electrical conductors within the
coiled tubing can
be connected to the bottom hole assembly at one end of the string; and at the
opposite end of
the string, the conductors can be connected to meters, gauges, control
equipment, computers,
1o and the lilce.
The transmission of signals through composite coiled tubing does present one
problem, however. When two or more lengths of tubing must be joined to provide
the
required overall length for the particular well operation, a connector must be
provided to pass
the energy or data between adjoining lengths of coiled tubing. Such a
connection must first
provide a robust electrical contact between the two lengths of wire to be
joined so that an
uninterrupted signal may pass even in the presence of the shalung and jarring
that occur
during a well operation. In addition the connection must provide insulation.
The connected
conductors must not only be insulated from the fluids and other matter in the
surrounding
well environment but in addition the connected conductors must be properly
insulated from
2o the other conductors within the composite tubing. Materials that are
present in the well
environment can be highly corrosive and destructive of electrical conductors.
A common
shortcoming of the existing methods for connecting composite coiled tubing is
that they do
not adequately meet the need for a robust and well insulated electrical
connection of the
electrical conductors in the joined sets of tubing.
Notwithstanding the foregoing described prior art, there remains a need for a
coiled
tubing connector that combines the features of a strong mechanical connection,
sealing the
fluids within the coiled tubing from the outside environment, and providing a
robust electrical
connection. These and other features and advantages are found in the present
invention.
SUMMARY OF TIDE INVENTION
3o The present invention overcomes the aforementioned deficiencies of the
prior art by
providing a connector that comprises female and male housings which join
together to create
the coiled tubing connection. A rotating ring on the male housing includes
threads that
engage corresponding threads on the female housing. Spindles on the male
housing also
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align with corresponding flutes on the female housing. The female and male
housings each
attach to end portions of coiled tubing through a clamp or threaded
connection.
A first advantage of the connector of the present invention is that it
provides a robust
connection to join successive lengths of composite coiled tubing. In this way
forces of
compression, tension and torque can be passed along the length of composite
drill string.
Another advantage of the connector of the present invention is that it
provides a
hydraulic seal to separate the fluids passing through the interior of the
coiled tubing from
fluids and materials passing externally of the coiled tubing. The connector
also allows fluids
to pass uninterrupted from one length of tubing to the succeeding length of
tubing.
1o Composite tubing may not hold a perfectly round cross-section. The fact
that
composite tubing is flexible allows it to bend to an out-of-round cross-
section. The connector
of the present invention assures that the coiled tubing will be strongly bound
and sealed to the
connector in spite of the tubing's tendency to be out-of-round. The connector
achieves this
advantage by providing hydraulic seals.
A further advantage of the present invention is that the connector may be
assembled
without imparting rotational forces on either length of coiled tubing.
A further advantage of the present invention is that it provides for a strong,
well
protected contact between matched pairs of electrical conductors in adjoining
lengths of
composite tubing. This contact is achieved through matching sets of ring
contacts. The ring
2o contact attached to the male end has a spring back located underneath the
mating surface of
the ring contact. Thus when the male contact ring engages the female contact
ring, the spring
bacl~ firmly engages the contacts.
Another advantage of the electrical contact achieved through the present
connector is
the insulation it provides from the surrounding well environment as well as
between the
neighboring electrical signals from adjacent conductors.
Another advantage of the connector is that many of the parts in the sub-
assembly of
the connector are the same for both the male and female pieces of the
connector. Thus, there
is no need for additional designs, drawings, or inventory. The same part may
be used for
construction of either the male or female housing.
3o Thus, the present invention comprises a combination of features and
advantages that
enable it to overcome various problems of prior art coiled tubing connectors.
The various
characteristics described above, as well as other features, objects, and
advantages, will be
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readily apparent to those skilled in the art upon reading the following
detailed description of
the preferred embodiments of the invention, and by referring to the
accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
For a detailed description of a preferred embodiment of the present invention,
reference will now be made to the accompanying drawings, which form a part of
the
specification, and wherein:
Figure 1 is a cross-sectional view of a connector connecting two lengths of
composite
tubing;
Figure 2 is a cross sectional view of the male housing of the connector;
l0 Figure 3 is a cross-sectional view of the female housing of the connector;
Figure 4 is a cross-sectional view of the clamping sub-assembly of the
connector;
Figure 5 is a cross-sectional view of the female end piece of the connector;
Figure 6 is a cross-sectional view of the male end piece of the connector;
Figure 7 is a cross-sectional view of a split ring wedge.
DES CRIPTION OF THE PREFERRED EMB ODIMENTS
The present invention is susceptible to embodiments of different forms. There
are
shown in the drawings, and herein will be described in detail, specific
embodiments of the
present invention with the understanding that the present disclosure is to be
considered an
exemplification of the principles of the invention, and is not intended to
limit the invention to
2o that illustrated and described herein.
The coiled tubing connector of the present invention includes a female and a
male
housing which join together to create the coiled tubing connection. A rotating
ring on the
male housing includes threads that engage corresponding threads on the female
housing.
Splines on the male housing also align with corresponding grooves on the
female housing.
The female and male housings each attach to end portions of coiled tubing
through a clamp
connection. Passageways or conduits within the female and male housings also
allow
electrical conductors embedded within each piece of coiled tubing to pass to
ring contacts.
Ring contacts on both the female and male housings also align when the
housings are
connected so as to allow electrical energy or signals to pass from one length
of coiled tubing
3o to the next.
Refernng initially to Figure 1, there is shown one preferred embodiment of a
connector 10 for connecting adjacent lengths 12, 14 of composite coiled
tubing. The
connector 10 comprises a male housing 20 and female housing 40.
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Referring now to Figure 2, the male housing 20 is generally in the form of a
hollow
cylinder. Moving generally from right to left in Figure 2, several features of
the male
housing are shown. Splines 28 are machined on or affixed onto an exterior edge
of said male
housing. An inner electrical contact 50 is also positioned on male housing 20.
Inner
electrical contact 50 is generally cylindrical in shape and includes both
electrical contacts or
rings 51 and wiper seals 52. Inner electrical contact 50 generally rests on
the outer radius of
male housing 20. Contact rings 51 are composed of any electrical conductor,
and wiper seals
52 are composed of an electrical insulator.
Still referring to Figure 2, rotating ring 27 is positioned on male housing
20. Rotating
ring 27 rotates freely around the barrel of male housing 20; however rotating
ring 27 does not
slide axially along the length of male housing 20. Rotating ring 27 is
prevented from sliding
along the length of male housing 20 by a lock ring 30 and may be prevented by
conventional
mechanical devices such as splines or stops. Rotating ring 27 also includes
threads 31 on its
exterior surface.
Another feature of male housing 20 and rotating ring 27 is the presence of
seals 29.
In the preferred embodiment of this invention, seals 29 are positioned on the
surfaces of the
male housing 20 and the rotating ring 27, respectively. However, the seals
could also be
positioned on female housing 40. The seals themselves are composed of an
elastomeric
material that will allow a compression seal to form against the hydraulic
pressures
encountered in the well. As shown, seals 29 may be positioned into grooves,
recesses or
rings positioned on the male housing 20 and rotating ring 27.
Referring now to Figure 3, female housing 40 is shown. Like male housing 20,
the
female housing 40 is also generally cylindrical in form. Female housing 40
includes slots or
grooves 48 and receiving threads 41. Female housing 40 also has sealing
surfaces 49 and
outer electrical contact 60, both positioned on the internal diameter of
female housing 40.
Outer electrical contact 60 is generally cylindrical in shape and includes
outer
electrical plates or rings 61. In a preferred embodiment, the outer electrical
contact 60
contains an outer electrical ring 61 for each conductor on the inner
electrical contact 50.
Contact rings 61 may be composed of any conducting material. Outer electrical
rings 61 are
not separated by wiper seals but by a plastic insulator, not shown. Outer
electrical contact 60
is positioned on the inner radius of female housing 40. Electrical rings 61
are connected to
conductors embedded in composite tubing 14 that is joined to female housing
40.
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Both male housing 20 and female housing 40 share many common features. For
ease
of discussion, these common features are identified below together.
Referring again to Figures 2 and 3 there is shown a passage 71 and conforming
seal
72. The conforming seals 72 are composed of an elastomeric material that will
allow a
compression seal to form under hydraulic pressure.
Both male and female housings include axial passageways 73. These passageways
are hollows or grooves, approximately of the diameter or clearance of an
electrical wire. The
passageways may take any of several shapes depending on the ultimate shape of
the
connector 10 and the chosen method of manufacture.
1o In a preferred embodiment, the male housing 20, female housing 40, and
rotating ring
27 have a plurality of apertures 32, 34, and 42 drilled into each member.
Both male housing 20 and female housing 40 include an outer conical housing 43
and
inner skirt 44. Encircling inner skirt 44 on both male and female housings is
split ring wedge
45. In a preferred embodiment, the outer diameter of split ring wedge 45 is
straight and the
inner diameter is tapered. The conical housing 43 has a straight outer
diameter and a tapered
inner diameter. The inner sltirt 44 has a straight inner diameter and a
tapered outer diameter.
The split ring wedge 45 itself is manufactured from a material that shows
strength at high
stress and yet is relatively flexible. Beryllium copper has been used as a
suitable material.
The other components of both the female and male housing 40, 20 are
constructed of any
high strength material, such as steel, and preferably of a material that will
resist corrosion.
Referring still to Figure 2 and 3 there is shown a transition 53, 54 in the
internal
diameter of male and female housings 20, 40.
In a preferred embodiment the inner electrical contact 50 and outer electrical
contact
60 each have four contact plates or rings 51, 61. This number is selected as
it corresponds to
the number of conductors disposed in the typical coiled tubing 12, 14 in use.
A different
number of contact rings may be used. Both inner electrical contact 50 and
outer electrical
contact 60 may contain wiper seals such as seals 52. Wiper seals, formed of an
elastomeric
insulating material, create ridge-like separations between electrical contacts
51, 61. In a
preferred embodiment wiper seals are only present on inner electrical contact
50 and not on
outer electrical contact 60.
Also shown on Figures 2 and 3 are caps 36, 46 positioned on the male and
female
housings. These caps are not part of the assembled connector; however, they
are attached to
each housing during manufacturing to allow for handling and to prevent foreign
matter from
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entering and possibly damaging the housings. In a preferred embodiment, the
structure of
both the male and the female housings 20, 40 may consist of separate parts
that assemble into
the final housing.
Refernng now to Figure 4, a clamping sub-assembly 80 includes pieces of both
the
male and female housing and may be converted into either a male housing or a
female
housing by the assembly of additional parts. A shirt or liner support 81 is
shown as a
separate piece of the clamping sub-assembly 80. The liner support 81 is joined
to the body of
the clamping sub-assembly 80 through a suitable fastener such as a threaded
connection or a
pressed fitting. Joining the clamping sub-assembly 80 to the liner support 81
are metal and
to plastic seals 82, 83, which themselves contain o-ring elastomeric seals 84.
Figure 4 also
shows a stop clamping ring 85 forming a separate part of the clamping sub-
assembly 80. The
stop clamping ring 85 forms an underlying structure upon which the outer
conical housing
43, inner shirt 44, and split ring 45 are mounted.
Referring again to Figure 3, the clamping sub-assembly 80 further includes a
plug 86
and adapter 87. Figure 3 also shows the clamping sub-assembly 80 further
converted to the
final female housing 40 through the addition of a female retainer sleeve 88
and female end
piece 89. Figures 5 and 6 provide a detailed views of female retainer sleeve
88 and female
end piece 89. Similarly, Figure 2 shows the clamping sub-assembly 80 converted
into the
male housing 20 through the addition of male end-piece 90 and rotating ring
27.
2o The assembly of male housing 20 and female housing 40 creates the complete
connector 10. Assembly of the male and female housings 20, 40 begins by
aligning splines
28 located on the male housing 20 with the grooves 48 located on female
housing 40. The
female housing 40 is constructed with an inner diameter at one end, and the
male housing is
constructed with a reciprocal outer diameter, so that said male housing 20 may
sealingly
engage the female housing 40 in assembly.
When male housing 20 is connected to female housing 40, the threads 31 of
rotating
ring 27 engage the receiving threads 41 of female housing 40. Rotating ring 27
is then
rotated so that threads 31 threadingly lock into receiving threads 41. Because
rotating ring 27
freely rotates around the barrel 33 of male housing 20, the male housing 20
and female
housing 40 do not themselves rotate upon the rotation of rotating ring 27. In
this way, the
male housing 20 may be firmly connected to the female housing 40 without
imparting any
twisting or torsional forces on the lengths of composite coiled tubing 12, 14
that are
connected to male and female housings 20, 40.
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The plurality of apertures 31, 34 and 42 drilled into male housing 20, female
housing
40, and rotating ring 27 assist in the connection of male housing 20 to female
housing 40.
Apertures 32, 34, and 42 in housing 20, ring 27 and housing 40, respectively,
include
projections from a connection tool (not shown) used to join the lengths 12, 14
of composite
coiled tubing at the job site. The engagement allows the connection tool to
engage, grasp or
manipulate male housing 20, female housing 40, and rotating ring 27. During
the assembly
step, male housing 20 and female housing 40 are held stationary through use of
apertures 32
and 42. At the same time the rotating ring 27 is rotated, through use of
apertures 34, so as to
join male housing 20 to female housing 40 as described above.
to Although apertures 32, 34, 42 have been described for engaging a connection
tool, it
will be apparent that other methods may be used. For example the apertures 32,
34, 42 may
have various shapes. Likewise, instead of apertures, flats may be machined
onto these
members so as to allow wrenching tools to apply forces at these flats. In
addition, chains or
frictional tools may be applied to non-machined, smooth surfaces on male
housing 20, female
i5 housing 40, and rotating ring 27 to apply the necessary gripping forces.
Seals 29 present on male housing 20 and rotating ring 27 are compressed onto
corresponding sealing surfaces ~49 on female housing 40 when male housing 20
is joined to
female housing 40. In this manner the assembled connector 10 provides a fluid-
tight seal that
isolates fluids in the interior of the coiled tubing 12, 14 from the fluids
around the outside of
20 the coiled tubing 12, 14. Seals 29, 37 are placed on male housing 20 and
rotating ring 27 for
ease of manufacturing and could be equally positioned on female housing 40.
Attachment of the coiled tubing 12, 14 to the connector 10 is similar for both
the male
and female housings 10, 40. Referring again to Figures 2 and 3, there is shown
lengths 12, 14
of composite tubing joined to male housing 20 and female housing 40. Male and
female
25 housing 20, 40 include an outer conical housing 43 and inner shirt 44.
Encircling inner skirt
44 is split ring wedge 45. As can be seen, the end of composite tubing 14 is
fitted around
split ring wedge 45 and inside the inner radius of outer conical housing 43.
As the outer
conical housing 43 is drawn against the inner shirt 44, composite tubing 14 is
compressively
clamped in place against ring wedge 45. Additionally, split ring wedge 45 will
be drawn
30 tightly against the composite tubing 14 as the outer conical housing 43 is
compressed against
inner skirt 44.
In practice it may be advantageous to affix male housing 20 and female housing
40 to
the ends of the composite coiled tubing at the factory, job site, or other
work site. In that way
CA 02403960 2002-09-18
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lengths of coiled tubing that are preassembled with connector ends may then be
shipped to
the job site. At the job site the male and female portions of the connector
may then be joined
as needed.
Frictional forces hold the conical housing 43, inner skirt 44, and composite
tubing
together. In practice clamping forces are achieved such that the strength of
the tubing-to
housing bond exceeds the strength of the coiled tubing itself.
When assembling the conical housing 43, inner slcirt 44, and split ring wedge
45 to
the composite tubing, it is beneficial to cut a taper 56 on the end of the
composite tubing 12,
14. The tapers on the conical housing 43, inner skirt 44, split ring wedge 45,
and the
l0 composite tubing 12, 14 are preferably of approximately the same degree in
order to achieve
a firm connection. A preferred degree of taper is approximately 1 1/z degrees.
Referring now to Figure 7, there is shown a preferred split ring wedge 45 that
is
generally cylindrical in shape. The wall thickness of split ring wedge 45
tapers from one end
to the other. Further the degree of taper is such that when positioned around
inner skirt 44,
the inner surface 47 of split ring wedge 45 will bear at all points of surface
47 against inner
shirt 44. The outer surface 49 of split ring wedge 45 will also press at all
points against
composite tubing 14 so as to clamp composite tubing 14 against the inner
bearing surface of
outer conical housing 43. Split ring wedge 45 does not form a continuous
cylinder shape,
however. A split 46 runs along the length of split ring wedge 45. The split 46
allows split
ring wedge 45 to compress as outer conical housing 43 compresses against inner
skirt 44. An
identical method is used to join the composite tubing to the male housing 20
as that just
described with respect to the joining the composite tubing to the female
housing 40. Thus,
the composite tubing is likewise joined to the male housing 20 through a
friction joint
including an outer conical housing 36, an inner skirt 37, and a split ring
wedge 38.
As previously stated, when the coiled tubing lengths 12, 14 are connected to
female
and male housings 40, 20, it is advantageous to taper the end of the coiled
tubing that is to be
connected. When forming the taper on the end of the coiled tubing, it is also
preferred to
strip out a working length of the embedded conductors. The conductors are
first passed
through axial passageways 73, shaped into the female and male housings 40, 20,
that allow
the conductor to pass from the end of the coiled tubing to the inner
electrical contact 50 and
outer electrical contact 60.
In a preferred embodiment, the conductors from the composite tubing 12, 14 are
not
connected directly to the inner electrical contact 50 or the outer electrical
contact 60. Rather
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the contact plates or rings 51, 61 of both the inner electrical contact 50 and
outer electrical
contact 60 are manufactured with separate conductor leads (not shown). These
leads are
themselves drawn through passageways 73 in male and female housings 20, 40.
During
assembly the conductors originating from the coiled tubing are connected or
soldered to the
lead conductors originating from the contact plates 51, 61. This conductor-to-
conductor
connection is then covered by a pressure boot (not shown). A pressure boot is
essentially an
elastomeric seal that keeps out fluids from the conductor-to-conductor contact
by pressure
means. Pressure boots are known in the industry.
Inner electrical contact 50 and outer electrical contact 60 are positioned on
male and
1o female housings 20, 40, respectively, so that when male housing 20 is
joined to female
housing 40 to form connector 10, the electrical rings 51 of inner electrical
contact 50 match
up and make electrical contact with outer electrical rings 61 disposed on
outer electrical
contact 60. Either or both inner electrical contact 50 and outer electrical
contact 60 may have
a spring back or biasing members that act to hold inner electrical contact 50
and outer
electrical contact 60 in firm contact with each other.
Each contact ring 51, 61 is mounted radially and is positioned to mate with a
corresponding ring S 1, 61. There is an advantage to having the rings 51, 61
mounted in a
radial position in that the electrical contact does not then depend on the
relative radial
positions of male and female housings 20, 40. Rather, it is the relative axial
position of both
2o male and female housings 20, 40 that assures the proper alignment and
contact between each
contact ring 51, 61. Thus, the inner and outer contacts 51, 61 are positioned
to align when in
the axial position that is achieved when male arid female housings 20, 40 are
completely
connected. There is no need to position the housings 20, 40 in a particular
radial position in
order to achieve an electrical contact.
The wiper seals 52 found on the inner electrical contact 50 serve a function
during
assembly. The dimensions of the male and female housing diameters are such
that during
their assembly into the connector 10, wiper seals 52 are partially compressed.
Further,
assembly of male and female housings 20, 40 drag the partially compressed
wiper seals 52
across the electrical contacts rings 61 of outer electrical contact 60. This
dragging action
3o serves to wipe the contact rings 61 clean of any contaminating material,
thus assuring a clean
mating surface for inner and outer electrical contacts 50, 60.
In operation, once male housing 20 is firmly joined to female housing 40, the
assembled connector 10 passes forces of tension and compression up and down
the coiled
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CA 02403960 2002-09-18
WO 01/73331 PCT/USO1/08172
tubing string. In this way successive lengths 12, 14 of coiled tubing may be
drawn into the
well or extracted from the well. When splines 28 are engaged with grooves 48,
torsional
forces in one length of tubing are passed to the connected length of another
tubing.
Additionally, the alignment of splines 28 and grooves 48 allows for a precise
rotational
alignment of male housing 20 and female housing 40. .
The assembled connector IO also provides a sealed passage for the fluids that
are
conducted in the coiled tubing. During assembly, seals 29 sealingly engage
with receiving
surfaces 49. Thus the fluids can pass up and down successive lengths 12, 14 of
coiled tubing,
through the connector 10, without contacting the materials on the exterior of
the coiled
to tubing.
Referring again to Figure 1, transitions 53, 54 in the internal diameter of
male housing
20 and female housing 40 respectively of the connector 10 direct the fluid as
the fluid passes
from one length of the coiled tubing and into the connector 10. The fluid
encounters a
gradual tapered decrease in the internal diameter of the connector 10 as it
enters and as the
fluid passes out of the connector 10 to another length of the coiled tubing,
the internal
diameter gradually increases. Thus the taper assists with fluid flow. The
gradual taper in the
connector 10 reduces turbulence in the flowing fluid. The reduced fluid
turbulence serves the
added benefit of reducing harm or damage to the interior of the connector 10.
Referring again to Figures 2 and 4, inner skirt 81 extends for some distance
along the
2o inner diameter of the coiled tubing. The purpose of the extended length of
the inner shirt 81
is to provide a support on which the coiled tubing can rest. The support will
prevent the
coiled tubing from over flexing and breaking, at the point where the coiled
tubing is attached
to female housing 40. The length of the inner shirt 44 is preferably from
between 1 to 20
times the diameter of the coiled tubing.
Refernng again to Figures 2, 3, and 4, there is shown a passage 71 and
conforming
seal 72. Passage 71 allows fluid communication between the interior of
composite tubing 12,
14 and conforming seal 72. Conforming seal 72 is made of a deformable material
such as
rubber or an elastomer. Thus, when fluid in the interior of the coiled tubing
flows into
passage 71, pressure in the fluid will fill conforming seal 72. In this manner
conforming seal
72 acts to seal coiled tubing against the male and female housings 20, 40.
Electrical signals are transmitted through the conductors embedded in coiled
tubing
I2, 14. These conductors pass through passageways 73 in male housing 20 until
they malce
electrical contact with electrical contact rings 51 of inner electrical
contact 50. At this point,
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CA 02403960 2002-09-18
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the electrical signals, or electrical energy if the cables are energy-carrying
conductors, pass
from inner electrical contact 50 to outer electrical contact 60. The signals
are further
transmitted through the female housing 40 through the passageways 73 in the
female housing
40 and on into the cables of the coiled tubing 14 that is attached to the
female housing 40.
Wiper seals 52 also serve to isolate and insulate the contact rings 61 from
the fluids
and other materials that are either outside the composite tubing 12, 14, or
being conducted
inside the composite tubing 12, 14. Thus wiper seals 52 protect the contact
rings 51, 61 from
chemical corrosion and physical decay. By insulating the metal plates or rings
51, 6l,,wiper
seals S2 also assure that an uninterrupted contact is maintained between the
conducting
conductors of the upper and lower lengths 12, 14 of the coiled tubing. Finally
wiper seals 52
also act to insulate individual electrical rings 51, 61 from each other. Thus
no signal
interference or power loss occurs as a result of crossed or fouled connections
among the
electrical plates.
While a preferred embodiment of the invention has been shown and described,
modifications thereof can be made by one skilled in the art without departing
from the spirit
or teaching of this invention. The embodiments described herein are exemplary
only and are
not limiting. Many variations and modifications of the system and apparatus
are possible and
are within the scope of the invention. Accordingly, the scope of protection is
not limited to
the embodiments described herein, but is only limited by the claims that
follow, the scope of
2o which shall include all equivalents of the subject matter of the claims.
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