Note: Descriptions are shown in the official language in which they were submitted.
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APPARATUS FOR CONNECTING DOWNHOLE TOOLS TO A WIRELINE
The present invention relates to an apparatus for connecting downhole tools to
a
wireline or other electrical conductor and more particularly to an apparatus
that allows
the relatively quick connection and disconnection between different downhole
tools.
BACKGROUND
After an oil or gas well is drilled, further completion services must be
performed
on the well before it can be used to produce oil or gas. Completion of the
well typically
involves running in tubing and associated downhole tools for cementing casing
in the
well, logging the well, perforating the casing, stimulating the surrounding
production
zone, etc.
Many of these completion services use a wireline as an electrical conductor.
Wireline is used in wireline and workovers and typically comprises a single or
multi-
strands. It can be used both for well intervention and formation evaluation
operations
prior to perforation.
Two completion services that are typically done before a well can be used to
produce oil or gas are: logging and perforating. Logging is performed by
lowering an
electrical cable (typically a wireline) connected to a tool containing sensors
down the
well bore to obtain and transmit data about the well bore back to the ground
surface. This
data can include resistivity, conductivity, formation pressure, sonic
properties and well
bore dimensions.
Perforating is carried out to create small holes or perforations in the well
casing so
that oil or gas can pass through the casing, through the perforations and into
the well
bore. To perforate the casings, first a perforation gun is lowered down the
well bore to a
desired location in the well bore. This location will typically be a
production zone where
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oil or gas from the reservoir will enter the well bore through the casing and
is typically
determined using the data obtained from the logging of the well bore. The
perforating
gun uses formed explosives to perforate the well casing. Typically, the
perforating gun is
set off by an electrical signal sent from the ground surface through a
conductor running
down the well bore to the perforating gun.
Both logging and perforating on horizontal wells are typically done by
conveying
an electrical conductor (such as a wireline) into a well bore and the
electrical conductor is
typically conveyed into the well bore using coiled tubing. To convey an
electric
conductor into a wellbore with coiled tubing, first the electrical conductor
is typically
inserted coaxially into the coiled tubing. After insertion of the electric
conductor into the
coiled tubing, one end of the electric conductor is connected to a cable head.
The cable
head is used to provide a mechanical and electrical connection from the
electrical
conductor to the down-hole tool that will be attached.
Like any process operation, there are many logistical problems associated with
well drilling and completion. Whether it is the electric conductor breaking or
a drill bit
wearing out, a pipe or tool falling accidentally into the bottom of the well;
or the
reconnections of the down hole tools while changing from logging to
perforation, it all
leads to down time. Anything that can be done to lessen these down times can
be greatly
beneficial.
One logistical problem that can occur that can result in significant downtime
is
the breaking of the electrical conductor in the wireline while the tool and
wireline is
being run downhole. The cable head that the wireline is connected to is
affixed to the
coiled tubing in such a way that the motion of the coiled tubing as it
traverses the
wellbore is transmitted to the down-hole tools. As these tools are lowered
into the
wellbore attached to the end of the coiled tubing using the cable head,
tension is exerted
on the tool and the electrical conductor, which, if pulled to tight, may
damage or break
the electrical conductor in the wireline and initiate tool failure.
Additionally, any pulling
of the electrical conductor and the wireline can result in the electrical
conductor being
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torn off and a loss of electrical connection. The integrity of the electric
conductor and its
probability of breaking in perforating and logging activities is a rate
controlling step.
This problem can become acute whenever the down hole tool, wireline and coiled
tubing
is to be directed through a horizontal or highly deviated well.
If the electrical conductor is damaged or broken, the coiled tubing must be
withdrawn from the well and the electrical connection remade before the coiled
tubing
with the down hole tool on the end, can be re-lowered down the well. It can
also require
the cable head to be fished out of the well before it can be repaired and
reconnected to the
coil tubing. Initiation of fishing operation involves shutting down the
activities,
sometimes for days; all the while the operator continues to be liable for
operational fees.
Delay can also occur from having to switch the components from logging to
perforating components. Coiled tubing used to push tools down highly deviated
or
horizontal well bores is hamstrung by a large set-up time for assembly of
various
components during interchanging between the operations of logging and
perforating the
wells. Logging and perforating use different types of down-hole tools; with
the logging
operation using a tool containing a number of sensors and the perforating tool
being a
collar locator attached to the top of a perforating gun. Typically, changing
the
components requires the electrical conductors to be switched, different cable
heads
attached to electrical conductors, different tools to be attached, etc. This
can result in
significant set up time loss (time to prepare for operations) while shifting
between the
assemblies (perforating & logging). This is a time consuming process typically
involving
cutting & re-connection of the electric conductor and the coiled tubing.
SUMMARY OF THE INVENTION
A quick disconnect assembly device is provided that allows various downhole
tools to be
relatively quickly connected to the quick disconnect assembly device and an
electric
wireline without having to disconnect the wireline from a cablehead.
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In one aspect, the quick disconnect assembly device can have an upper pack off
assembly, a pack off rubber and a lower pack off assembly that is connectable
to an end
of coiled tubing while a wireline passes through a bore of these components. A
logging
barrel can then be attached to the lower pack off assembly. To connect a
logging tool to
the quick disconnect barrel, a split receiver can be placed around a cable
head and
connected to the logging barrel. To connect another type of downhole tool,
such as a
perforating gun, to the quick disconnect assembly device, the split receiver
can be
removed and a perforating barrel slid over the cable head and attached to an
end of the
logging barrel without disconnecting the cable head from the wireline.
DESCRIPTION OF THE DRAWINGS
A preferred embodiment of the present invention is described below with
reference to the
accompanying drawings, in which:
Fig. I is a schematic view of a system for providing completion services for a
well;
Fig. 2 is an exploded schematic view a quick disconnect coupling device
configured to connect to a logging tool; and
Fig. 3 is an exploded schematic view of the quick disconnect coupling device
of
Fig. 2 configured to attach to a collar locator and perforating gun.
DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS
Fig. I illustrates a completion services system 10 for logging and perforating
a
well 20. The completion services system 10 can include a wireline unit 30 for
running
wireline 32 and a coiled tubing unit 40 for providing coiled tubing 42 to be
run down a
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bore 22 of a well 20. Wireline 32 provided by a wireline unit 30 can be
inserted into a
bore of the coiled tubing 42 and the coiled tubing 42 and wireline 32 can then
be inserted
down the bore 22 of the well 20. The wireline 32 will comprise at least one
electrical
conductor and typically outer cabling to give the wireline 32 tensile
strength.
The completions services system 10 can include a quick connect coupling device
100 that allows a tool 50, such as a logging tool, perforating tool, etc., to
be quickly
transferred on the distal end 24 of the coiled tubing 42 down the bore 22 of
the well 20
while maintaining the integrity of the wireline 32.
Referring to Fig. 2 an exploded view of the quick connect coupling device 100
is
shown. The quick disconnect coupling device 100 allows a data logging tool
(not shown)
to be connected to a cable head 110 and a wireline 32 that passes through a
bore 46 of the
coiled tubing 42. The wireline 32 can comprise an electrical conductor 36 with
one or
more support wires 38 provided around the electrical conductor 36 to increase
the tensile
strength of the wireline 32. The end 34 of the wireline 32 is connected to the
cablehead
110 with the support wires 38 mechanically connected to the cablehead 110 and
the
electrical conductor 36 electrically connected to the cable head 110.
The quick disconnect coupling device 100 can be used to securely connect the
cablehead 110 to the distal end 24 of the coiled tubing 20 and can include: a
sealing
assembly 118 having an upper pack-off assembly 120, a pack-off rubber 130 and
a lower
pack-off assembly 140; a logging barrel 150; and a split receiver 160.
The upper pack off assembly 120 can connect to the distal end 44 of the coiled
tubing 42 and can be designed to prevent leakage of fluid into the bore 46 of
the coiled
tubing 42 through its distal end 44. A first end 121 of the upper pack off
assembly 120 is
configured to form a seat 123 for the pack-off rubber 130 and a second end 122
of the
upper pack off assembly 120 is designed to be inserted into the bore 46 at the
distal end
44 of the cable tubing 46. The second end 122 of the upper pack off assembly
120 can be
provided with an outer diameter substantially equal to the inner diameter of
the bore 46
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of the coiled tubing 42. The second end 122 of the upper pack off assembly 100
can
contain a number of grooves 124 for holding sealing elements 125 such as
elastomeric o-
rings. The sealing elements 125 can form a seal with an inner surface of the
bore 46 of
the coiled tubing 42 when the second end 122 of the upper pack off assembly
100 is
inserted into the distal end 42 of the coiled tubing 42.
The first end 121 of the lower pack off assembly 100 can be provided with
threads 126 on the outer surface of the first end 122.
An inner bore 128 can be provided in the upper pack off assembly 120, running
coaxial through the upper pack off assembly 100, to allow the wireline 32 to
pass through
the upper pack off assembly 120, through the inner bore 128.
The pack off rubber 130 can be used to act as another seal to prevent fluid
from
the bore 22 of the well 20 from entering the bore 46 of the coiled tubing 42.
The pack off
rubber 130 can have an inner bore 132 running through the pack off rubber 130
to allow
the wireline 32 to pass through the pack off rubber 130.
In one aspect, the pack off rubber 130 can be made of an elastomer material.
The lower pack off assembly 140 can have a first end 141 and a second end 142.
The second end 142 of the lower pack off assembly 140 can be configured to
form a seat
143 for the pack off rubber 130. The second end 142 of the lower pack off
assembly 140
can be provided with threads 144 on an inner surface of the second end 142.
These
threads 144 can be sized to mate with the threads 126 on the outer surface of
the first end
121 of the upper pack assembly 120. In this manner, the pack off rubber 130
can be
inserted between the second end 142 of the lower pack off assembly 140 and the
upper
pack off assembly 120 and then the upper pack off assembly 140 and the lower
pack off
assembly 120 can be threaded together.
The first end 141 of the lower pack off assembly 140 is connectable to the
logging
barrel 150. The first end 141 can have an outer diameter that is sized to be
inserted into
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an inner bore 155 of the logging barrel 150 and be provided with a groove 145
running
circumferentially around the outer diameter of the first end 141 of the lower
pack off
assembly 140. The groove 145 can be used to receive shear screws (not shown)
that are
used to connect the logging barrel 50 to the first end 141 of the lower pack
off assembly
140.
The lower pack off assembly 140 can have an inner bore 146 passing coaxially
through the lower pack off assembly 140 to allow the wireline 32 to pass
through the
lower pack off assembly 140. The inner bore 146 of the lower pack off assembly
140,
the inner bore 132 of the pack off rubber 130 and the inner bore 128 of the
upper pack off
assembly 120 can be positioned so that they are all aligned with one another
when the
lower pack off assembly 140, pack off rubber 130 and the upper pack off
assembly 120
are all connected together, allowing the wireline 32 to pass through the lower
pack off
assembly 140, the pack off rubber 130 and the upper pack off assembly 120.
The logging barrel 150 can be used to adapt the coiled tubing 42 and wireline
32
to the logging tool, perforating gun or other downhole tool. The logging
barrel 150 can
have a first end 151, a second end 152 and an inner bore 155. A series of
apertures 153
can be positioned circumferentially around the second end 152 of the logging
barrel 50.
The first end 151 of the logging barrel 150 can have threads 154 on the inside
surface of
the inner bore 155.
The logging barrel 150 can be connected to the lower pack off assembly 140 by
sliding the second end 152 of the logging barrel 150 over the first end 141 of
the lower
pack of assembly 140. With the second end 152 of the logging barrel 150 in
place over
the first end 141 of the lower pack of assembly 140 and the apertures 153 in
the logging
barrel 150 aligned with the groove 145 on the first end 141 of the lower pack
of assembly
140, shear screws (not shown) can be inserted through the apertures 153 and
extending
into the groove 145 on the lower pack of assembly 140.
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The logging barrel 150 and the lower pack off assembly 140 can be made to
swivel by connecting the logging barrel 150 and the lower pack of assembly 140
with the
shear screws (not shown), if the shear screws are not fully tightened. This
can be used to
allow the logging barrel 150 to rotate relative to the coiled tubing 42 to aid
in the
connection of a tool to the quick disconnect coupling device 100. This can
increase the
ease with which the tool is connected, i.e. allowing a tool to be easily
threaded onto the
quick disconnect coupling device 100.
Once the tool is connected, the shear screws can be tightened to prevent the
logging barrel 150 from rotating relative to the lower pack off assembly 140
when the
tool is pushed downhole.
The shear screws allow the logging barrel 150 to be sheared from the lower
pack
off assembly 140. The amount of shear that can be withstood before the logging
barrel
150 and the lower pack off assembly 140 separate can be adjusted by changing
the
number of shear screws used to connect the logging barrel 150 to the lower
pack off
assembly 140, the material making up the shear screws or the cross-sectional
area of the
shear screws. Referring again to Fig. 1, in the event that the downhole tool
50 becomes
stuck in the bore 22 of the well 20, the logging barrel 150 can be sheared
from the lower
pack off assembly 140 to disconnect the coiled tubing 44 from the downhole
tool 50.
Referring again to Fig. 2, the wireline 32 can be run through the inner bore
155 of
the logging barrel 150.
The split receiver 160 can be used to connect the cable head 110 and a logging
tool (not shown) to the quick disconnect assembly device 100 and the coiled
tubing 42.
The split receiver 160 can comprise two portions 164A, 164B that when mated
together
can fit over the cable head 110 and hold the cable head 110 securely in placed
between
the two portions 164A, 164B of the split receiver 160. Each portion 164A, 164B
of the
split receiver 160 can have a first end 161 and a second end 162 with threads
163
provided on the second end 162 of the two portions 164A, 164B. These threads
163 can
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be on the outer periphery of the split receiver 160 when the two portions
164A, 164B are
positioned against one another over the cable head 110.
An inner passage 165 of the two halves 160A, 160B of the split receiver 160
can
be configured to match the shape of the cable head 110. In one aspect, the
cable head
110 can be shaped so that with a fish head, etc. so that the inner passage 165
can hold the
cable head 110 preventing the cable head 110 from moving axially relative to
the split
receiver 160. In one aspect, the cable head 110 can have an neck 112 that
mates with a
protrusion 168 in the inner passage 165, so that the protrusion 168 extends
into the neck
112 of the cable head 110 when the two portions 164A, 164B are positioned
around the
cable head 110.
When the two portions 164A, 164B of the slit receiver 160 are positioned
around
the cable head 110, the second ends 162 of the two portions 164A, 164B can be
inserted
into the first end 151 of the logging barrel 150 with the threads 163 threaded
into the
threads 154 on the inner surface of the inner bore 155 of the logging barrel
150 to secure
the split receiver 160 to the logging barrel 150. In this manner, when the
tool and the
coiled tubing 42 is pushed or pulled when being inserted or withdrawn from the
well 20,
substantially all the force is transferred from the tool through the quick
disconnect
assembly device 100 to the coiled tubing 42, rather than the wireline 32.
In operation, the quick disconnect assembly device 100 can be used with a
wireline or other electrical conductor to connect a down hole tool to the
wireline. The
quick disconnect assembly device 100 can be connected on the distal end 44 of
a piece of
coiled tubing 42 with a wireline 32 inserted through the bore 46 of the coiled
tubing 42
for use. The wireline 32 can be passed through the bore 128 of the upper pack
off
assembly 120, the bore 132 of the pack off rubber 130 and the bore of the
lower pack off
assembly 140 so that the end 34 of the wireline 32 extends out of the lower
pack off
assembly 140. The wireline 32 will need to extend some distance out of the
distal end 44
of the coiled tubing 42 so that the it can pass through the different
components of the
quick disconnect assembly device 100. The lower pack off assembly 140 and the
upper
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pack off assembly 120 can then be connected together with the rubber pack off
130
secured between them. The assembly of the lower pack off assembly 140, the
rubber
pack off assembly 130 and the upper pack off assembly 120 can then be
connected to the
distal end 44 of the coiled tubing 42 by inserting the second end 122 of the
upper pack off
assembly 120 into the coiled tubing 42 allowing the sealing elements 125 to
seal against
the inner surface of the bore 46 of the coiled tubing 42.
The logging barrel 150 can then be inserted over the wireline 32 so that the
wireline 32 passes through the inner bore 155 of the logging barrel 150 and
the logging
barrel 150 attached to the lower pack off assembly 140. The second end 152 of
the
logging barrel 150 can be placed over the first end 141 of the lower pack off
assembly
140 so that the apertures 153 in the second end 152 of the logging barrel 150
are provided
over the groove 145 in the first end 141 of the lower pack off assembly 140.
Shearing
screws (not shown) can then be inserted through the apertures 153 and
extending into the
groove 145 on the lower pack off assembly 140 to connect the logging barrel
150 and the
lower pack off assembly 140.
With the logging barrel 150, the lower pack off assembly 140, pack off rubber
130 and the upper pack off assembly 120 connected to the coiled tubing 42, the
end 34 of
the wireline 32 can be connected to the cable head 110. The necessary
mechanical
connections and electrical connections can be made so that the wireline 32 is
connected
to the cable head 110. The support wires 38 can be mechanically connected to
the second
end 34 of the cable head 110, while the electrical conductor 36 can be
mechanically
connected to the cable head 110 by a wireline shear 109 and electrically
connected to the
cable head 110.
To attach a logging tool (not shown) to the quick disconnect assembly device
100,
the split receiver 160 can be placed around the cable head 110 by placing each
portion
164A, 164B around the cable head 110 and threading the second end 162 of the
split
receiver 160 into the logging barrel 150. With the split receiver 160 in place
securing the
cable head 110 inside the inner passage 165 formed between the two portions
164A,
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164B, the split receiver 160 can operatively and fixedly connect the cable
head 110 to the
quick disconnect device 100.
With the logging tool in place, connected to the quick disconnect assembly
device
100, the logging tool can be run downhole on the distal end 44 of the coiled
tubing 42 to
log the well.
The quick disconnect assembly device 100 allows down hole tools besides
logging tools to relatively quickly be attached to the distal end 44 of the
coiled tubing 42
and the wireline 32 without disconnecting the wireline 32 and its electrical
conductor 36
from its electrical connection with the cable head 110. Fig. 3 illustrates the
quick connect
coupling device 100 configured for attaching to a perforating or other
downhole tool (not
shown). In this configuration, the upper pack off assembly 120, the rubber
pack off 130,
the lower pack off assembly 140 and the logging barrel 150 are used. However,
the split
receiver 160 is not used, but rather, a perforating barrel 200 is used in
place of the split
receiver 160 to allow other types of tools, such as perforating guns, bridge
plugs, etc.
The perforating barrel 200 can be used to run additional types of tools such
as
perforating guns, bridge plugs, etc. down hole and can have a first end 202
and a second
end 204. The second end 204 of the perforating barrel 200 can have threads 206
that will
mate with the threads 154 on the first end 151 of the logging barrel 150. The
logging
barrel 150 can have an inner bore 209 that is sized large enough to
accommodate the
cable head 110 within the inner bore 209. The first end 202 of the logging
barrel 150 can
be provided with threads 208 that can mate with a down hole tool (not shown)
such as a
perforating gun. In one aspect, the end 104 of the cable head 110 can also be
provided
with threads 105.
In operation, the perforating barrel 200 can be used to connect a different
downhole tool to the quick disconnect device assembly 100 without
disconnecting the
electrical or mechanical connection between the wireline 32 and the cable head
110. If a
logging tool (not shown) is connected to the end of the quick disconnect
device assembly
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100, as shown in Fig. 2, the quick disconnect assembly device 110 and the
logging barrel
200 can be used to relatively quickly attach a different down hole tool such
as a
perforating gun to the coiled tubing 42. First, the split receiver 160 can be
removed from
the quick disconnect assembly device 100 by unthreading it from the logging
barrel 150
and removing it from the cable head 110 without disconnecting the wireline 32
or the
electrical conductor 36 from the cable head 110. With the split receiver 160
removed, the
logging barrel 150 can be positioned over the cable head 110 with the cable
head 110 in
positioned in the inner bore 209 of the perforating barrel 200. The
perforating barrel 250
can then be connected to the rest of the quick connect assembly device 100 by
threading
the second end 202 of the perforating barrel 200 into the first end 151 of the
logging
barrel 150. To attach a downhole tool to the perforating barrel 200, the first
end 202 of
the perforating barrel 200 and the first end 104 of the cable head 110 can be
connected to
a casing collar locator (not shown) which in turn can be connected to various
downhole
tools which are adaptable to the casing collar locator. The casing collar
locator can
secure the perforating barrel 200 and the cable head 110 relative to one
another so any
force placed on the downhole tool is transferred through the quick disconnect
assembly
100 to the coiled tubing 42 and vice versa. The downhole tool can then be
lowered down
the bore 22 of the well 20 on the distal end 44 of the coiled tubing 42 to the
desired depth
and the downhole tool activated using the electrical conductor 36 and the
wireline 32.
The foregoing is considered as illustrative only of the principles of the
invention.
Further, since numerous changes and modifications will readily occur to those
skilled in
the art, it is not desired to limit the invention to the exact construction
and operation
shown and described, and accordingly, all such suitable changes or
modifications in
structure or operation which may be resorted to are intended to fall within
the scope of
the claimed invention.
