U.S. patent application number 14/115313 was filed with the patent office on 2014-03-27 for setting and retrieval device.
This patent application is currently assigned to INTERWELL TECHNOLOGY AS. The applicant listed for this patent is Terje Stormo. Invention is credited to Terje Stormo.
Application Number | 20140083677 14/115313 |
Document ID | / |
Family ID | 46052727 |
Filed Date | 2014-03-27 |
United States Patent
Application |
20140083677 |
Kind Code |
A1 |
Stormo; Terje |
March 27, 2014 |
SETTING AND RETRIEVAL DEVICE
Abstract
A setting and retrieval device includes a first connection
device connected to a first connection interface of a plugging
device and a second connection device connected to a second
connection interface of the plugging device. The device includes a
charging device having first and second fluid chambers, a
displaceable charging piston, a power supplying device included a
fluid pump device for pumping fluid between the first and second
fluid chambers via first and second fluid channels, and a volume
adjusting device including a volume adjusting piston displaceable
into the first fluid chamber. The energy storing device is charged
with potential energy by the charging piston moving in a first
direction by pumping fluid from the first to the second fluid
chamber and the energy stored in the energy storing device is
discharged by movement in a second, axial, direction between the
first and second connection devices.
Inventors: |
Stormo; Terje; (Trondheim,
NO) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Stormo; Terje |
Trondheim |
|
NO |
|
|
Assignee: |
INTERWELL TECHNOLOGY AS
Ranheim
NO
|
Family ID: |
46052727 |
Appl. No.: |
14/115313 |
Filed: |
April 27, 2012 |
PCT Filed: |
April 27, 2012 |
PCT NO: |
PCT/EP2012/057764 |
371 Date: |
December 6, 2013 |
Current U.S.
Class: |
166/181 |
Current CPC
Class: |
E21B 33/13 20130101;
E21B 23/04 20130101; E21B 33/12 20130101 |
Class at
Publication: |
166/181 |
International
Class: |
E21B 33/13 20060101
E21B033/13; E21B 33/12 20060101 E21B033/12 |
Foreign Application Data
Date |
Code |
Application Number |
May 3, 2011 |
NO |
20110689 |
Claims
1. A setting and retrieval device for setting and/or retrieval of a
plugging device in a well, the device comprising: a first
connection device comprising a first connection interface adapted
to be connected to a first plug connection interface of the
plugging device, wherein the first connection device comprises a
substantially sleeve-shaped body; a second connection device
comprising a second connection interface adapted to be connected to
a second plug connection interface of the plugging device, wherein
the second connection device comprises a substantially cylindrical
body, wherein the substantially cylindrical body is located
radially inside the substantially sleeve-shaped body and wherein
the first and second plug connection interfaces are located in a
lower end of the device; a charging device comprising a first fluid
chamber, a second fluid chamber and a displaceable charging piston,
wherein the first and second fluid chambers are separated by a
first separation wall protruding radially inwards from the
substantially cylindrical body; a triggering device adapted for
triggering discharge of potential energy stored in an energy
storing device; a power supplying device comprising a fluid pump
device for pumping fluid between the first and second fluid
chambers via a first fluid channel and a second fluid channel,
respectively; and a volume adjusting device comprising a first
volume adjusting piston displaceable into the first fluid chamber,
wherein the displaceable charging piston comprises a first end
facing towards the second fluid chamber and protruding radially
inwards from the substantially cylindrical body and a second end
facing towards the energy storing device, wherein a volume of the
second fluid chamber can be increased or decreased by movement of
the displaceable charging piston, wherein the first and second
fluid chambers are provided radially between an outer surface of
the substantially cylindrical body and an inner surface of the
substantially sleeve-shaped body, wherein the energy storing device
is charged with potential energy by the displaceable charging
piston moving in a first direction (A) caused by pumping fluid from
the first fluid chamber to the second fluid chamber by the pumping
device, and wherein a relative movement in a second, axial,
direction (B) between the first connection device and the second
connection device is caused by discharging the potential energy
stored in the energy storing device.
2. The device according to claim 1, wherein the displaceable
charging piston is movable in the second direction (B) during
discharge of the energy storing device.
3. The device according to claim 1, wherein the energy storing
device is a spring device.
4. The device according to claim 1, wherein the energy storing
device is configured to be compressed by the displaceable charging
piston.
5. The device according to claim 1, wherein the first fluid channel
is provided between the fluid pump device and the first fluid
chamber and wherein the second fluid channel is provided between
the fluid pump device and the second fluid chamber.
6. The device according to claim 1, wherein the first connection
device is provided radially outside the second connection
device.
7.-9. (canceled)
10. The device according to claim 1, wherein the first volume
adjusting piston is axially displaceable, wherein the axial
displacement of the first volume adjusting piston in a first
direction decreases the volume of the first chamber and axial
displacement of the first volume adjusting piston in a second
direction increases the volume of the first chamber.
11. The device according to claim 10, wherein the first volume
adjusting piston is provided radially between the first and second
connection devices.
12. The device according to claim 10, wherein the volume adjusting
device comprises a second volume adjusting piston comprising a
first end sealing an opening between the first and second
connection devices, wherein a spring device is provided axially
between a second end of the second volume adjusting piston and the
first volume adjusting piston.
13. The device according to claim 12, wherein the volume adjusting
device comprises a movement restraining device fixed to the first
volume adjusting piston for restraining the movement of the second
volume adjusting piston in relation to the first volume adjusting
piston.
14. (canceled)
15. The device according to claim 2, wherein the energy storing
device is a spring device.
16. The device according to claim 2, wherein the energy storing
device is configured to be compressed by the displaceable charging
piston.
17. The device according to claim 3, wherein the energy storing
device is configured to be compressed by the displaceable charging
piston.
18. The device according to claim 2, wherein the first fluid
channel is provided between the fluid pump device and the first
fluid chamber and wherein the second fluid channel is provided
between the fluid pump device and the second fluid chamber.
19. The device according to claim 3, wherein the first fluid
channel is provided between the fluid pump device and the first
fluid chamber and wherein the second fluid channel is provided
between the fluid pump device and the second fluid chamber.
20. The device according to claim 4, wherein the first fluid
channel is provided between the fluid pump device and the first
fluid chamber and wherein the second fluid channel is provided
between the fluid pump device and the second fluid chamber.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a National Stage application of
International Patent Application No. PCT/EP2012/057764, filed on
Apr. 27, 2012, which claims priority pursuant to 35 U.S.C.
.sctn.119(a) to Norwegian Patent Application No. 20110689, filed on
May 3, 2011. Both priority applications are hereby incorporated by
reference in their entirety.
FIELD OF THE INVENTION
[0002] The present invention relates to a setting and retrieval
device for setting and/or retrieval of a plugging device in a
well.
BACKGROUND OF THE INVENTION
[0003] There are known several setting tools for setting a plugging
device into a well, such as an oil and/or gas well. Typically, such
plugging devices are bridge plugs, straddle packers, gauge hangers
etc, which is set or fixed to the inside surface of the well during
a period in which a well operation is performed. In this period,
the setting tool must be removed from the well. Many such plugging
devices are retrievable, i.e. they must be retrieved from the well
after the well operation. A retrieval tool is used for such types
of retrieval operations.
[0004] Plugging devices have a run or retracted state, in which the
outer diameter is smaller than the inner diameter of the well in
order to transport the plugging device into and out from the well.
First, the setting tool is connected to the plugging device and the
plugging device is guided in its run state to the desired location.
Here, the setting tool is bringing the plugging device into its set
state, before the setting tool is disconnected from the plugging
device and removed out from the well. When the plugging device is
to be retrieved, the retrieval tool is guided into the well,
connected to the plugging device, and the retrieval tool is
bringing the plugging device to its run state and then the
retrieval tool together with the plugging device is transported out
from the well. One example of a plugging device is known from U.S.
Pat. No. 7,178,602 (in the name of Bronnteknologiutvikling AS)
[0005] To bring the plugging device from the run state to its set
state, and then from its set state and back to its run state, the
plugging device comprises an actuation interface. Often, this
actuation interface is actuated by moving a first or radially inner
part in an axial direction in relation to a second or radially
outer part. Shear pins are often used in the plugging device to
ensure that the plugging device is in its correct state--i.e. a
predetermined force must break one or several sets of shear pins in
order to actuate the plugging device. This is a common way to avoid
that the plugging device is accidentally brought to its set state
during the transport to and from the desired setting location in
the well. Such shear pins may require a weight of up to ca 2.5 tons
to break.
[0006] The object of the invention is to provide a setting and
retrieval device which gives an accurate and reliable actuation of
the plugging device between its run and set positions.
[0007] Moreover, a safety requirement for some oil and/or gas
companies is that it no pressurized devices are allowed on deck of
platforms and vessels due to the risk of personal injuries. Hence,
one object of the present invention is to provide a setting and
retrieval device which has no internal pressure before the setting
operation, and which has no internal pressure after the retrieval
operation.
SUMMARY OF THE INVENTION
[0008] The present invention relates to a setting and retrieval
device for setting and/or retrieval of a plugging device in a well,
comprising: [0009] a first connection device adapted to be
connected to a first connection interface of the plugging device;
[0010] a second connection device adapted to be connected to a
second connection interface of the plugging device; [0011] a
charging device comprising a first fluid chamber, a second fluid
chamber and a displaceable charging piston comprising a first end
facing towards the second fluid chamber and a second end facing
towards an energy storing device, where the first and second fluid
chambers are provided radially between the first and second
connection devices and where the energy storing device is charged
with potential energy as the charging piston moves in a first
direction by pumping fluid from the first chamber to the second
fluid chamber and where energy stored in the energy storing device
is discharged by providing a relative movement in a second, axial,
direction between the first connection device and the second
connection device; [0012] a power supplying device comprising a
fluid pump device for pumping fluid between the first and second
fluid chambers via a first fluid channel and a second fluid
channel; [0013] a volume adjusting device comprising a first volume
adjusting piston displaceable into the first fluid chamber.
[0014] In one aspect, the charging piston is movable in the second
direction during discharge of the energy storing device.
[0015] In one aspect, the energy storing device is a spring
device.
[0016] In one aspect, the energy storing device is configured to be
compressed by the charging piston.
[0017] In one aspect, the first fluid channel is provided between
the fluid pump device and the first fluid chamber and the second
fluid channel is provided between the fluid pump device and the
second fluid chamber.
[0018] In one aspect, the first connection device is provided
radially outside the second connection device.
[0019] In one aspect, the second connection device comprises a
substantially cylindrical body.
[0020] In one aspect, the first connection device comprises a
substantially sleeve-shaped body.
[0021] In one aspect, the first and second fluid chambers are
separated by a first separation wall protruding radially inwards
from the substantially cylindrical body.
[0022] In one aspect, the first volume adjusting piston is axially
displaceable, where the axial displacement of the volume adjusting
piston in a first direction decreases the volume of the first
chamber and axial displacement of the volume adjusting piston in a
second direction increases the volume of the first chamber.
[0023] In one aspect, the volume adjusting piston is provided
radially between the first and second connection devices.
[0024] In one aspect, the volume adjusting device comprises a
second axially displaceable volume adjusting piston comprising a
first end sealing the opening between the first and second
connection devices, where a spring device is provided axially
between a second end of the second volume adjusting piston and the
first volume adjusting piston.
[0025] In one aspect, the volume adjusting device comprises a
movement restraining device fixed to the first volume adjusting
piston for restraining the movement of the second volume adjusting
piston in relation to the first volume adjusting piston.
[0026] In one aspect, the device comprises a triggering device
adapted for triggering the discharge of the potential energy stored
in the energy storing device.
DETAILED DESCRIPTION
[0027] Embodiments of the invention will now be described with
reference to the enclosed drawings, where:
[0028] FIG. 1 illustrates a cross sectional view of a first
embodiment in a first state;
[0029] FIG. 2 illustrates a cross sectional view of a second
embodiment in a first state;
[0030] FIG. 3 illustrates a cross sectional view of a second
embodiment in a second state;
[0031] FIG. 4 illustrates a cross sectional view of a second
embodiment in a third state;
[0032] FIG. 5 illustrates a cross sectional view of a second
embodiment in a fourth state; and
[0033] FIG. 6 illustrates a cross sectional view of a third
embodiment.
[0034] In the following, the term "plugging device" is used to
describe any type of device which has a run state, in which the
device can be transported through a well, and a set state, in which
the device can be expanded and fixed to the inner surface of the
well.
[0035] The term "well" is used to describe oil and/or gas wells,
oil and/or gas pipes, water wells and/or water pipes, or other
types of wells and pipes in which a plugging device can be set.
[0036] It is now referred to FIG. 1, where a first embodiment of a
setting and retrieval device 1 is illustrated. The setting and
retrieval device 1 can be used for setting and/or for retrieval of
a plugging device in a well. In FIG. 1, the plugging device is only
indicated by its connection interfaces shown to the right in FIG.
1. It should be noted that for most plugging devices, the present
invention can be used for both setting operations and retrieval
operations. However, a plugging device might be designed so that
different tools are needed for their setting operation and their
retrieval operation, and hence, the present invention may only be
used for one of those operations.
[0037] The device 1 comprises a first connection device 2
comprising a first connection interface 2a adapted to be connected
to a first plug connection interface 2b of the plugging device.
Hence, the first connection device 2 itself comprises a second
connection interface 2a for connection to the first plug connection
interface 2b of the plugging device.
[0038] The device 1 also comprises a second connection device 3
comprising a second connection interface 3a adapted to be connected
to a second plug connection interface 3b of the plugging device.
Hence, the second connection device 3 itself comprises a second
connection interface 3a for connection to the second plug
connection interface 3b of the plugging device.
[0039] It should be noted that the design of the first and second
connection devices 2, 3 will of course depend on the design of the
first and second connection interface of the plugging device. Many
different designs for the first and second connection devices 2, 3
are possible with the present invention as long as the first and
second connection devices 2, 3 provide that a relative movement
between the first connection device 2 and the second connection
device 3 causes a relative movement between the first connection
interface and the second connection interface of the plugging
device.
[0040] In the present embodiment, the first connection device 2
comprises a substantially sleeve-shaped body 21 and the second
connection device 3 comprises a substantially cylindrical body 31.
The connection interfaces of the first and second connection
devices 2, 3 are located in the lower end of the device 1, that is,
the right end of the bodies 21, 31 in FIG. 1.
[0041] The first connection device 2 is provided radially outside
the second connection device 3, i.e. the cylindrical body 31 is
located radially inside the sleeve-shaped body 21. In the initial
position, as will be described below, the outer surface of the
first connection device provides the outer surface of the lowermost
part of the device 1.
[0042] A longitudinal or axial direction of the device 1 is defined
by the central axis I-I.
[0043] The device 1 further comprises a charging device 4 and a
main body 5. The main body 5 comprises a power supplying device
adapted to supply energy to the charging device 4. It should be
noted that the main body 5 is only partially shown in the
drawings.
[0044] The charging device 4 comprises a first fluid chamber 41 and
a second fluid chamber 42. The first and second fluid chambers 41,
42 are separated by a separation wall 43. In the present
embodiment, the separation wall 43 is protruding radially inwards
from the substantially cylindrical body 21, and is fixed to the
body 21. Alternatively, the wall 43 could be a part of the body 21
itself.
[0045] In the present invention, the first and second fluid
chambers 41, 42 are provided radially between the first and second
connection devices 2, 3, i.e. radially inside the first connection
device 2 and radially outside the second connection device 3.
[0046] The charging device 4 further comprises a displaceable
charging piston 44 comprising a first end 44a facing towards the
second fluid chamber 42 and a second end 44b facing towards an
energy storing device 45. The second end 44b comprises a radially
protruding stop flange to prevent the energy storing device 45 from
being damaged. Hence, the first end 44a of the charging piston 44
is protruding into the second fluid chamber 42, and by movement of
the charging piston 44, the volume of the second fluid chamber 42
can be increased or decreased.
[0047] The energy storing device 45 may be a spring device
configured to be compressed by the charging piston 44. The spring
device may be a gas spring, a cup or spiral spring etc. In FIG. 1,
the energy storing device 45 is a cup spring, which is supported by
an area 5a of the main body 5. The energy storing device 45 is in a
radial direction located between the second connection device 3 and
an axially protruding element 53 of the main body 5.
[0048] The energy storing device 45 is charged with potential
energy as the charging piston 44 moves in a first direction by
pumping fluid from the first chamber 41 to the second fluid chamber
42. The energy stored in the energy storing device 45 is discharged
by providing a relative movement between the first connection
device 2 and the second connection device 3 in a second, axial,
direction. The axial direction is parallel to the longitudinal
direction or central axis I-I of the device 1.
[0049] In FIG. 1, the first direction is indicated by arrow A and
the second direction is indicated by arrow B. In FIG. 1, the arrow
A is opposite of the arrow B, i.e. the charging movement of the
charging piston 44 is parallel to the second, axial direction.
However, it may also be possible that the movement of the charging
piston 44 in the first direction A is non-parallel to the second,
axial direction B, since it is the fluid flow between the first and
second chambers which provides the relative movement between the
first connection device 2 and the second connection device 3.
[0050] In the present embodiment, the charging piston 44 is also
moved in the second direction B during discharge of the energy
storing device 45.
[0051] It should also be noted that the discharge of the energy
storing device 45 may provide that the first connection device 2 is
moved axially while the second connection device 3 is stationary,
or that the first connection device 2 is held stationary while the
second connection device 3 is moved axially, or that both move
relative to each other in an axial direction. In the present
embodiment, the first connection device 2 is moved axially while
the second connection device 3 is stationary during the discharge
of the energy storing device. The second connection device 3 is
fixed to the structure of the main body 5.
[0052] The main body 5 comprises a fluid pump device 51 for pumping
fluid between the first and second fluid chambers 41, 42 via a
first fluid channel 11 and a second fluid channel 12. In FIG. 1 it
is shown that the first fluid channel 11 is provided inside the
cylindrical body 31 from the fluid pump device 51 to the first
fluid chamber 41, while the second fluid channel 12 is provided
inside the cylindrical body 31 from the fluid pump device 51 to the
second fluid chamber 42.
[0053] The main body 5 further comprises batteries or another type
of power source to supplying power to the fluid pump device 51.
[0054] The device 1 further comprises a volume adjusting device 7
for adjusting the volume of the first fluid chamber 41. The volume
adjusting device 7 comprises a first volume adjusting piston 71
displaceable into the first fluid chamber 41. The piston 71 is
provided radially between the first and second connection devices
2, 3.
[0055] According to the above, the first fluid chamber 41 is
limited by the volume adjusting piston 71, the wall 43, the outer
surface of the body 31 and the inner surface of the body 21. By
pumping fluid into or out from the first fluid chamber 41, the
piston 71 would move axially to the right or left of FIG. 1
respectively, assuming that the first and second connection devices
2, 3 are held stationary with respect to each other. Hence, the
axial displacement of the volume adjusting piston 71 in the first
direction decreases the volume of the first chamber 41 and axial
displacement of the volume adjusting piston 71 in the second
direction increases the volume of the first chamber 41.
[0056] According to the above, the second fluid chamber 42 is
limited by the axially protruding element 53 of the main body 5,
the piston 44, the wall 43, the outer surface of the body 31 and
the inner surface of the body 21. By pumping fluid into or out from
the second fluid chamber 41, the piston 44 will move axially to the
left or right of FIG. 1 respectively, assuming that the first and
second connection devices 2, 3 are held stationary with respect to
each other.
[0057] The device 1 may also comprise a triggering device 6 adapted
for triggering the discharge of the potential energy stored in the
energy storing device 45. The triggering device 6 could for example
be a shear pin which shears off at a predetermined load. In the
present embodiment, the triggering device 6 fixes the first
connection device 2 to an axial protruding element 53 of the main
body 5 and thereby prevents any axial displacement of the first
connection device 2 in relation to the second connection device 3.
Alternatively, the triggering device 6 in the form of a shear pin
may be located on the plugging device instead of the setting and
retrieval device 6.
[0058] The operation of the device of FIG. 1 will now be
described.
[0059] Initially, the first fluid chamber 41 is filled with
hydraulic fluid and the second fluid chamber 42 is empty or nearly
empty. The pressure of the hydraulic fluid in the first fluid
chamber 41 may be equal to the pressure at the surface
(platform/vessel etc). A plugging device which is to be set in the
well is connected to the first and second connection devices 2, 3,
as is known for a skilled person. The plugging device and the
setting and retrieval tool are then lowered to the desired position
in the well and the setting operation can start. During the
lowering process into the well, the volume adjusting piston 71 may
move axially due to the pressure variations.
[0060] First, hydraulic fluid is pumped from the first chamber 41
to the second chamber 42 by means of the fluid pump device 51 via
the first fluid channel 11 and the second fluid channel 12. The
fluid pump device 51 is supplied with power from the power supply
device.
[0061] Hence, as the fluid is pumped out from the first chamber 41,
the volume of the first chamber 41 decreases as the volume
adjusting piston 71 is moving towards the separation wall 43.
[0062] As the fluid is pumped in to the first chamber 42, the
volume of the second chamber 42 increases as the charging piston 44
is moving towards the energy storing device 45 and stores potential
energy in the energy storing device 45. In the present embodiment,
the potential energy is stored by compressing a cup spring.
[0063] When the potential energy has reached a certain level, the
triggering device 6, either of the plugging device or of the
setting and retrieval device 1, is triggered, and an axial movement
of the first connection device 2 in relation to the second
connection device 3 is no longer prevented. Hence, the first
connection device 2 is pressed towards the right of FIG. 1 due to
the energy stored in the energy storing device 45.
[0064] The result is that a controlled axial movement of the first
connection device 2 is achieved in the form of a stroke. The axial
movement is transferred to the plugging device and causes a setting
action of the plugging device, for example by radial expansion of a
packer, an anchor etc.
[0065] The process can then be repeated by pumping more fluid from
the first chamber 41 to the second chamber 42 for charging the
energy storing device 45 again. A second triggering device may then
be provided for triggering the second axial displacement of the
first connection device 2. The second triggering device may be
configured to withstand a higher load before breaking off than the
first triggering device. The process can be repeated as many times
as required, provided that the volume of the first fluid chamber 41
is sufficiently large. If the first axial movement did not move the
first connection device far enough, the fluid pump is used to move
the first connection device axially until the second triggering
device prevents further axial movement. When the plugging device is
set, the first and second connection devices 2, 3 are disconnected
from the plugging device and the device 1 is retrieved to the
surface. The pressure of the first and second fluid chamber 41, 42
can be aligned when there is no well pressure at the right side of
the volume adjusting piston 71 in FIG. 1 to avoid any pressure
inside the device 1 when retrieved to the deck of the platform.
Second Embodiment
[0066] The second embodiment will now be described with reference
to FIG. 2-5.
[0067] The second embodiment has the same features and functions as
the device of the first embodiment, and the same reference numbers
are used for the same features. These features will therefore not
be described here in detail.
[0068] The volume adjusting device 7 of the second embodiment
comprises a second axially displaceable pre-charge piston 72
comprising a first end 72a sealing the opening between the first
and second connection devices 2, 3, where a spring device 73 is
provided axially between a second end 72b of the second pre-charge
piston 72 and the first volume adjusting piston 71. In the present
embodiment, the spring device 72 is a cup spring. The pre-charge
piston 72 is used to pre-charge the charging device 4.
[0069] The volume adjusting device 7 may also comprise a movement
restraining device 74 fixed to the first volume adjusting piston 71
for restraining the movement of the second pre-charge piston 72
pre-charge piston 72 in relation to the first volume adjusting
piston 71.
[0070] The operation of the device of FIGS. 2-5 will now be
described.
[0071] As described, the first and second fluid chamber 41, 42 are
initially filled with hydraulic fluid. The volume of the second
chamber is small, nearly all the hydraulic fluid of the setting
tool is provided in the first fluid chamber 41. The pressure of the
hydraulic fluid in the first and second fluid chambers 41, 42 may
be equal to the pressure at the surface (platform/vessel etc).
Moreover, the positions of the different parts of the volume
adjusting device 7 are as shown in FIG. 2.
[0072] The plugging device and the setting and retrieval tool are
connected to each other and are lowered to the desired position in
the well, thereafter the setting operation can start. Since the
well pressure is larger than the surface pressure, the well
pressure will press the second pre-charge piston 72 towards the
first volume adjusting piston 71 during the lowering into the well,
and hence, the spring device 73 will be compressed, as shown in
FIG. 3.
[0073] In FIG. 4 it is shown that the pumping device has pumped
fluid from the first chamber 41 to the second chamber 42: The
volume adjusting piston 71 has moved towards the separation wall 43
and the charging piston 44 has moved towards the main body 5 and
has started the charging of the energy storing device 45. It should
be noted that the second piston 72 of the volume adjusting device 7
is limited due to the movement of the movement restraining device
74 fixed to the first volume adjusting piston 71. However, the
volume adjusting piston 71 moves in the same direction as the
charging piston 44. When the load threshold for the triggering
device 6 is reached, the potential energy stored in the energy
storing device is released through an axial displacement of the
first connection device 2. This operation can be repeated one or
several times depending of the design of the device 1, as mentioned
above for the first embodiment.
[0074] In FIG. 5 it is shown that the first connection device 2 has
been displaced to the right in relation to the second connection
device 3, and has contributed to a corresponding relative axial
displacement between connection interfaces of the plugging device.
In FIG. 5, the end position for the axial movement is achieved, by
the separation wall 43 abutting against a radially protruding stop
32 of the body 31 of the second connection device 2.
[0075] When the device 1 is to be retrieved, the fluid pressure of
the first and second chamber 41, 42 can be aligned by using the
pumping device actively or by opening a third fluid channel between
the chambers 41, 42. The second piston 72 of the volume adjusting
device 7 will also move and align the pressure inside the device 1
with the surrounding pressure.
[0076] Hence it is achieved that when the device 1 is retrieved
from the well and to the deck of the platform, there is no internal
pressure in the device 1.
Third Embodiment
[0077] A third embodiment is shown in FIG. 6. The third embodiment
has the same features and functions as the device of the second
embodiment, and the same reference numbers are used for the same
features. These features will therefore not be described here in
detail.
[0078] In the third embodiment, the substantially cylindrical body
31 of the connection device 3 comprises a third fluid channel or
bleed off channel 33 between an inner section 34 and an outer
section 35. The inner section 34 is closer to the main body 5 than
the outer section 35. The bleed off channel 33 provides that fluid
may flow between the first and second chambers 41, 42 in order to
bleed off the pressure difference between the first and second
fluid chambers. The bleed off channel 33 may comprise a separate
channel provided in the body 31, as indicated by the dashed line in
FIG. 6, or it may comprise one or several longitudinal grooves in
the body 31.
[0079] Alternatively, it may comprise a tapered area of the body
31, where the inner section 34 has a larger diameter than the outer
section 35. The bleed off channel is closed in the initial state,
but will open when the separation wall 43 is abutting against the
radially protruding stop 32 as shown in FIG. 6, here it is shown
that the separation wall 43 is passing the left opening of the
channel 33, thereby allowing fluid to flow between the first and
second chamber 41, 42.
[0080] Hence, in the state shown in FIG. 6, the fluid pressure is
aligned between the first chamber and the second chamber 41, 42.
Hence it is achieved that when the device 1 is retrieved from the
well and to the deck of the platform, there is no internal pressure
in the device 1.
[0081] It should be noted that the first, second and third
embodiments described above may be used to set and retrieve other
types of well plugging devices or well tools in addition to those
mentioned above. It should also be mentioned that the present
invention may also be used to set and retrieve plugging devices and
tools in other types of wells, such as water wells.
[0082] Moreover, it should be noted that the present invention can
be used for both setting operations and retrieval operations.
However, there might be plugging devices which may need a different
tool for either the setting operation or the retrieval operation.
In this situation, the device according to the invention will be a
setting tool only or a retrieval tool only.
[0083] It should also be noted that in addition to the elements and
parts of the device 1 described above, the device 1 also comprises
seals, O-rings etc for providing that the first and second chambers
41, 42 is tight with respect to fluid. Moreover, the body 31 and
body 21 may comprise several subparts to ease the assembly of the
device 1.
* * * * *