BLOWOUT PREVENTER AND LAUNCHER SYSTEM
Field of the Invention
The present invention relates to a blowout preventer for being mounted on a well
head, comprising a plurality of valves arranged in fluid communication with each
other, connected and forming a tubular pipe. Furthermore, the invention relates
to a launcher system, a well intervention module, a well intervention system and
a well system.
Background Art
During production of oil, it may become necessary to perform maintenance work
in a well or to open a production well. Such well work is known as well
intervention. Inside the well, a production casing is placed which in its upper end
is closed by a well head. The well head can be situated on land, on an oil rig or
on the seabed below water.
When a well head is situated on the seabed on deep water, well intervention is
more complicated since visibility below water can be poor. Furthermore, the
weather conditions at sea can interfere with the accomplishment of an
intervention and, in case of a rough sea, interrupt the intervention.
In regard to such subsea intervention operations, it is known practice to perform
these by lowering an intervention module from a surface vessel onto the well
head structure by means of a plurality of remotely operated vehicles (ROVs).
Before mounting the operational intervention module comprising the operational
tool or the like in a lubricator, a blowout preventer is mounted on the wellhead in
order to prevent blowouts. When connecting to an on-shore or terrestrial well
head, i.e. a well head not subsea, no ROV is needed.
A blowout preventer (BOP) is a large device with a series of valves (also referred
to as "rams") placed at the top of a well which can be closed for safety reasons
during drilling or other operations. The rams are designed to close if pressure
from an underground formation causes fluid, such as oil or natural gas, to enter
the wellbore and threaten the rig.
By closing the rams, undesired fluid flow can be prevented, thus making it
possible to regain control of the wellbore. Once the well is closed, the situation is
evaluated to determine the procedure required to return the well to safe
operating status.
A BOP can be installed above ground or under water. BOPs for deepwater wells
are powered and controlled remotely by means of hydraulic actuators. There are
three basic types of valves used in deepwater BOPs: One type of valve is a "ram"
which serves to seal off a pipe of a specific diameter by making a sharp
horizontal motion. Another type seals off pipes of various diameters. A third type
of BOP valve seals off the wellbore itself.
The largest oil spill in recent time, the Horizon Deepwater, occurred despite the
fact that the BOP employed valves of all the three above-mentioned types.
Summary of the Invention
It is an object of the present invention to wholly or partly overcome the above
disadvantages and drawbacks of the prior art. More specifically, it is an object to
provide an improved blowout preventer providing higher safety during deep sea
interventions.
The above objects, together with numerous other objects, advantages, and
features, which will become evident from the below description, are accomplished
by a solution in accordance with the present invention by a blowout preventer for
being mounted on a well head, comprising:
- a plurality of valves arranged in fluid communication with each other, connected
and forming a tubular pipe,
wherein the blowout preventer further comprises a display visible from outside
the blowout preventer.
In one embodiment, the display may be a digital display.
Further, the blowout preventer as described above may comprise a housing
sealing off a space in which the display is arranged.
Moreover, the housing may be made of a material thermally and/or pressuringly
isolating the display from an outside temperature and/or pressure so that the
temperature and/or pressure in the space is maintained within a predetermined
range.
Also, said blowout preventer may further comprise an environmental control
device for controlling the temperature and/or pressure within the housing.
Additionally, the environmental control device may comprise a heat exchanger
device for keeping the temperature of the display within a predetermined
temperature range.
In an embodiment, the environmental control device may comprise a chamber
comprising gas and a valve for letting the gas into the space or from the space
into the chamber.
Furthermore, the environmental control device may comprise an accumulator.
In addition, the housing may have a face plate made of a transparent material.
Moreover, the display may be connected with a processing unit for displaying
information on the display.
Said housing may be filled with liquid for controlling the temperature and/or the
pressure surrounding the display.
In an embodiment, the display may comprise a receiving and/or transmitting unit
so that the display has data transmission capability to a remote operating centre.
The blowout preventer may further comprise a storing device for storing
measurements and received or transmitted signals or recorded data.
The invention furthermore relates to a blowout preventer for being mounted on a
well head, comprising:
- a frame structure, and
- a plurality of valves arranged in fluid communication with each other, forming a
tubular pipe which is fastened to the frame structure,
wherein the blowout preventer further comprises a storing device for storing
measurements, signals or recorded data.
The blowout preventer as described above may further comprise a display.
This display may be a flat display panel, a light-emitting diode display, a vacuum
fluorescent display, a liquid crystal display, an electroluminescent display, a thinfilm
transistor display, a surface-conduction electron-emitter display, or a
nanocrystal display.
Moreover, the blowout preventer may comprise a transparent cover covering the
display or monitor to fluidly seal off the display or monitor.
The cover may be made of glass or plastic.
Furthermore, the blowout preventer may comprise a control unit comprising the
storage device, and a communication unit for communicating with and
transmitting and/or receiving data to and/or from the display or monitor.
The control unit may comprise a receiving and/or transmitting unit enabling the
control unit to transmit data to and from a remote operating centre.
Additionally, the blowout preventer may comprise a sensor for sensing the
temperature and/or well fluid pressure inside the well.
Moreover, the blowout preventer may further comprise a docking station enabling
an operational tool in the well to connect to the blowout preventer and be
charged or recharged, or to upload or download information or signals to and
from the communication unit.
The present invention furthermore relates to a launcher system for launching a
downhole tool through a well head, comprising a lubricator closed off at a first
end by a blind cap, a downhole tool arranged in the lubricator, a lubricator valve
arranged to close off the lubricator at a second end opposite the first end, a
shear ram valve connected with the lubricator valve, and a connector for
connecting the launcher system to a blowout preventer or a well head.
The launcher system may further comprise a second lubricator valve arranged
between the shear ram valve and the connector.
Further, the launcher system according to the present invention may comprise a
digital display arranged inside a fluid-tight housing and visible from outside the
system.
This display may be a flat display panel, a light-emitting diode display, a vacuum
fluorescent display, a liquid crystal display, an electroluminescent display, a thinfilm
transistor display, a surface-conduction electron-emitter display, or a
nanocrystal display.
Furthermore, the launcher system may comprise a disconnection unit arranged
between the lubricator valve and the connector for disconnecting a part of the
launcher system.
Moreover, the launcher system may comprise a docking station arranged at the
first end of the lubricator to enable the tool to connect with the docking station
and be charged, recharged, and/or communicate data to and/or from the tool.
This docking station may comprise a Universal Series Bus (USB) to enable
communication with the tool.
In addition, the blowout preventer may comprise a power unit, such as a battery.
Furthermore, the blowout preventer may comprise a supporting structure.
Additionally, the downhole tool may be wireless and driven only by an internal
power source in the downhole tool.
Furthermore, the tool may comprise an inductive coupling for charging or
recharging power and transmitting and/or receiving information.
Moreover, the tool may comprise a rotating device, such as a turbine, engaged in
the fluid flow during production for charging or recharging power.
The present invention also relates to a well intervention module for performing
well intervention operations in a well, comprising a blowout preventer and a
supporting structure as described above.
Furthermore, the invention relates to a well intervention module for performing
well intervention operations in a well, comprising a launcher system as described
above and a supporting structure.
The well intervention module may further comprise an attachment means for
removably attaching the supporting structure to a structure of a well head or an
additional structure, a navigation means and a well manipulation assembly.
Said well intervention module may further comprise a digital display arranged
inside a fluid-tight housing and visible from outside the system.
In an embodiment, the navigation means may comprise a buoyancy system
adapted for regulating a buoyancy of the submerged well intervention module.
Furthermore, the well intervention module may have a top part and a bottom
part, the bottom part having a higher weight than the top part.
In another embodiment, the supporting structure may be a frame structure.
Furthermore, the frame structure may have an outer form and defines an internal
space containing the well manipulation assembly and the navigation means, the
well manipulation assembly and the navigation means both extending within the
outer form of the frame structure.
In addition, the navigation means may have at least one propulsion unit for
manoeuvring the module in the water.
Furthermore, the supporting structure may be a frame structure having a height,
a length and a width corresponding to the dimensions of a standard shipping
container.
The well intervention module as described above may further comprise a control
system for controlling the well manipulation assembly, the navigation means, the
buoyancy system and the intervention operations.
Furthermore, the supporting structure may be a frame structure having an outer
form and defining an internal space containing a control system, the control
system extending within the outer form of the frame structure.
Additionally, the navigation means may comprise at least one guiding arm for
gripping around another structure in order to guide the module into place.
Moreover, the navigation means may comprise a detection means for detecting a
position of the intervention module.
In an embodiment, the buoyancy system may comprise a displacement tank, a
control means for controlling the filling of the tank, and an expansion means for
expelling sea water from the displacement tank when providing buoyancy to the
module to compensate for the weight of the intervention module itself in the
water.
Moreover, the detection means may comprise at least one image recording
means.
Additionally, the well manipulation assembly may comprise a tool delivery system
comprising at least one tool for being submerged into the well, and a tool
submersion means for submerging the tool into the well through the well head,
and it may furthermore comprise at least one well head connection means for
being connected to the well head, and a well head valve control means for
operating at least a first well head valve for providing access of the tool into the
well through the well head connection means.
Furthermore, the tool delivery system may comprise at least one driving unit for
driving the tool forward in the well.
Additionally, the well manipulation assembly may comprise a cap removal means
for removing a protective cap from the well head.
The well intervention module may further comprise a power system for supplying
power to an intervention operation, such as a cable from the surface vessel, a
battery, a fuel cell, a diesel current generator, an alternator, a producer or
similar power supplying means.
In an embodiment, the power system may comprise a power storage system for
storing energy generated from an intervention operation, such as submersion of
an operational tool into the well.
In another embodiment, the power system may have enough reserve power for
the control system to disconnect the well head connection means from the well
head, the cable for providing power from the power system, the wireline from the
intervention module, or the attachment means from the well head structure.
Furthermore, the supporting structure may, at least partly, be made of hollow
profiles.
Moreover, the hollow profiles may enclose a closure comprising a gas.
The present invention furthermore relates to a well intervention system
comprising a well intervention module as described above and a remotely
operated vehicle for navigating the intervention module onto the well head or
another module.
In an embodiment, the remotely operated vehicle may comprise a camera and/or
a communication device for communicating with a control unit of the blowout
preventer.
The well intervention system may further comprise an intervention module as
described above and a remote operating center for communicating with the
intervention module and a downhole tool in the well.
In an embodiment, the tool may comprise an inductive coupling for charging or
recharging power and transmitting and/or receiving information, e.g. through the
docking station.
Moreover, the tool may comprise a rotating device, such as a turbine, engaged in
the fluid flow during production for charging or recharging power, e.g. through
the docking station.
Furthermore, the well intervention system may comprise a plurality of sensors
arranged in the well for sensing the temperature and/or well fluid pressure inside
the well.
Moreover, the well intervention system may comprise a downhole tool having a
sensing device for sensing the temperature and/or well fluid pressure inside the
well.
In addition, the system may further comprise at least one remote control means
for remotely controlling some or all functionalities of the intervention module, the
remote control means being positioned above water.
Additionally, the well intervention system may comprise at least one autonomous
communication relay device for receiving signals from the intervention module,
converting the signals into airborne signals, and transmitting the airborne signals
to the remote control means, and vice versa, to receive and convert signals from
the remote control means and transmit the converted signals to the intervention
module.
In an embodiment, the intervention module or parts of the intervention module
may be made of a metal, such as steel or aluminium, or a lightweight material
weighing less than steel, such as polymers or a composite material, e.g. glass or
carbon fibre reinforced polymers.
The present invention also relates to a well system for launching a downhole tool
through a well head, comprising:
- a launcher system according to the present invention
- a well comprising a safety valve arranged at least 10 metres down in relation to
the well head,
wherein the well further comprises a docking station enabling connection to an
operational tool in the well for charging or recharging power and transmitting and
receiving information and data, such as control instructions regarding the next
scheduled operation or logging.
The tool, such as a downhole tractor, propelling itself forward in the well, may be
capable of propelling itself up to the surface with a certain amount of data
quantity faster than the same amount of data can be transferred from the tool in
the well to the surface by a communication cable.
Moreover, the docking station may be arranged below the safety valve.
In an embodiment, the tool may comprise an inductive coupling for charging or
recharging power and transmitting and/or receiving information.
Furthermore, the tool may comprise a rotating device, such as a turbine,
engaged in the fluid flow during production for charging or recharging power.
Finally, the present invention relates to the use of the blowout preventer, the
launcher system or a well intervention module as described above for performing
a well intervention.
Brief Description of the Drawings
The invention and its many advantages will be described in more detail below
with reference to the accompanying schematic drawings, which for the purpose of
illustration show some non-limiting embodiments and in which
Fig. 1 shows a blowout preventer mounted on a well head,
Fig. 2 shows an intervention module comprising a launcher system ready to be
mounted on the blowout preventer,
Fig. 3 shows the intervention module of Fig. 2 mounted on the blowout
preventer,
Fig. 4 is a schematic view of an intervention operation,
Fig. 5 is a schematic view of an intervention module according to the invention
docked on a well head,
Fig. 6 is a schematic view of an intervention module according to the invention,
Figs. 7 and 8 are schematic views of two embodiments of buoyancy systems ac
cording to the invention,
Fig. 9 is a schematic view of one embodiment of an intervention module,
Fig. 10 is a schematic view of another embodiment of an intervention module,
Fig. 11 shows one embodiment of a well intervention system,
Fig. 12 shows another embodiment of the intervention system,
Fig. 13 shows yet another embodiment of the intervention system,
Fig. 14 shows a perspective view of the display in a housing,
Fig. 15 shows a cross-sectional view of the diplay, and
Fig. 16 shows a cross-sectional view of another embodiment of the display.
All the figures are highly schematic and not necessarily to scale, and they show
only those parts which are necessary in order to elucidate the invention, other
parts being omitted or merely suggested.
Detailed description of the invention
Fig. 1 shows a blowout preventer 1 mounted to a well head 2 arranged on the
seabed on deep water. The blowout preventer 1 could also be mounted to a well
head 2 arranged on-shore or terrestrially or to a well head arranged above water
on a rig or vessel. In the following, the blowout preventer 1 will primarily be
explained in relation to subsea well heads, but the invention is applicable to all
types of well heads.
The blowout preventer 1 comprises a plurality of valves 3, 4 arranged on top of
each other, and thus in fluid communication with each other. The first valve is an
annular valve 3 and the rest of the valves are rams 4. The valves 3, 4 are
connected and form part of a tubular pipe 14. I n the end closest to the rams, the
tubular pipe is connected with the well head 2, and in the other end, the tubular
pipe may be connected with an intervention module 100.
The blowout preventer 1 is arranged in a supporting structure 110 in the form of
a frame structure, and together with the frame structure it forms an intervention
module 100. Furthermore, the blowout preventer 1 comprises a display 5 on its
outside to enable a diver or a Remotely Operated Vehicle (also called an ROV) to
read the display.
The display is a digital display so that all kinds of information can be displayed at
the screen and the information to be displayed can be changed without changing
any equipment in the display. The well has several sensors which provide
information about the condition of the well, e.g. the safety valves send acoustic
signals to the top of the well regarding their position and concerning whether
they are open or closed. The display may thus be connected with a processing
unit 23 for displaying information on the display, and the processing unit 23 is
thus connected with the control unit 8 comprising the storage device, and a
communication unit 9 for communicating with and transmitting and/or receiving
data to and/or between the display or monitor and the sensors 10 for sensing the
temperature and/or well fluid pressure inside the well. By having a digital display
and a processing unit 23, information can be changed on the display as easily as
on a pc screen on a desktop.
On on-shore, terrestrial or other well heads 2 placed above water, the display 5
comprises a receiving and/or transmitting unit so that the display has data
transmission capability to a remote operating centre. The remote operating
centre may thus be arranged in the nearest town and still be able to control a
park of wells, and thus well heads 2, without viewing the display 5. The blowout
preventer 1 may also comprise a control unit 8 comprising a receiving and/or
transmitting unit enabling the control unit to transmit data to and from a remote
operating centre. Communicating with and receiving and/or transmitting data to
and from the remote operating centre may take place by means of a satellite,
and thus, satellite communication equipment is comprised in the control unit or
the display 5.
The display 5 is arranged in connection with the tubular pipe 14 next to the
valve, also called a ram 4. The display 5 is positioned inside a display housing 15,
and the front of the display is covered by a transparent front plate 16 to fluidly
seal off the display 5. The display housing 15 has been mounted on the tubular
pipe 14 and forms part of the pipe. The display 5 is connected to sensors 10
inside the pipe 14 and displays the measured data of the sensor on the display 5
which is visible from outside the blowout preventer through the transparent front
plate. The sensors measure the condition inside the tubular pipe 14 below the
valve and thus also the conditions of the well fluid inside the well. The sensors 10
sense the temperature and/or the pressure of the well fluid inside the well.
The display 5 is a flat display panel, but may also be another kind of display,
such as a light-emitting diode display, a vacuum fluorescent display, a liquid
crystal display, an electroluminescent display, a thin-film transistor display, a
surface-conduction electron-emitter display, or a nanocrystal display.
In Fig. 2, the blowout preventer 1 comprises a control unit 8 further comprising a
storage device 6 and a communication unit 9 for communicating with the display
5. The storing device 6 is used for storing measurements, signals or recorded
data and is arranged in the display housing 15 behind the display 5. The storing
device 6 stores the data from the sensor measurements and thus functions as a
"black box" so that when an ROV connects to the display housing 15, the data
can be read by the ROV or be read into a communication box of the ROV. When
the ROV emerges to the vessel or the rig, the data can be read into a computer
and analysed. In this way, an approaching failure can be predicted as the signs of
such a failure can be read from the well fluid conditions before it accelerates and
causes damage in the well and a leak of oil mud into the sea.
Some of the main objectives of intervention are to gather information about the
downhole production and the well condition by using data acquisition equipment.
Accurate diagnosis of the well may be necessary in order to determine
unexpected performance as well as to verify the composition and rates from the
different zones open to production. This approach is essential in order to select
the best possible reservoir and the best production management techniques. The
diagnosis is also used as valuable input for future heavier well intervention
operations.
In Fig. 3, the blowout preventer 1 further comprises a power unit 13, such as a
battery, for powering the display 5, the sensors 10 and the control unit 8. In
another embodiment, the display 5, the sensors 10 and the control unit 8 each
comprise a power unit 13. As can be seen in Fig. 3, the power unit 13 is
positioned in a way that enables an ROV to recharge it by connecting to it from
outside the blowout preventer 1.
The transparent front plate in the form of a cover is made of glass or plastic or
similar transparent material.
In one embodiment, the control unit 8 comprises an analysing unit used to
compare a measurement of a sensor to the previous measurement of that
sensor. If the measurement is the same as the previous measurement, the new
measurement replaces the old, and thus the storing device does not store any
useless measurements.
The blowout preventer 1 forms part of an intervention module 100 for performing
well intervention operations in a well. As can be seen in Figs. 1-3, the
intervention module 100 comprising the blowout preventer 1 is connected as the
first intervention module to the well head 2. Subsequently, another intervention
module comprising a launcher system comprising a downhole tool in a lubricator
is connected to the first intervention module comprising the blowout preventer.
Figs. 2 and 3 show a launcher system 210 for launching a downhole tool 171
through a well head 2 subsea. The launcher system 210 comprises a lubricator
(178) which is closed off by a blind cap 211 at a first end. The downhole tool 171
is arranged in the lubricator, and at its other and second end, the lubricator is
closable by a lubricator valve 205. The lubricator valve 205 is connected with a
shear ram valve 206, and a connector 212 for connecting the launcher system to
a blowout preventer 1 or a well head 2 is arranged at the bottom of the launcher
system 210. For security reasons, the launcher system 210 also comprises a
second lubricator valve below the shear ram valve 206. The first lubricator valve
is also called a swap valve, and the second lubricator valve is also called a
hydraulic master valve.
Furthermore, the launcher system 210 comprises a disconnection unit 213
arranged between the first lubricator valve and the first shear ram valve for
disconnecting a part of the launcher system in case of an uncontrollable well
situation. In this way, the launcher system 210 can also be disconnected and
reused for other well intervention operations. Furthermore, a riser-based system
for a light semisubmersible intervention rig can be used for heavy fluid circulation
in the well.
The shear ram valve is part of a control system which can be operated by an ROV
or a diver or from a vessel or rig through an umbilical or by means of WIFI, 3G,
acoustics or wireless communication. The shear ram valve is designed so that it
is able to cut trough a tool and close it off completely to make a fluid-tight seal.
As can be seen in Figs. 2 and 3, the launcher system 210 further comprises a
docking station 211 arranged at the first end of the lubricator so that the tool can
connect with the docking station and be charged, recharged, and/or
communicate data to and/or from the tool. The tool then passes the blowout
preventer 1 and subsequently enters into the lubricator for docking into the
docking station. The docking station 211 comprises a Universal Series Bus (USB)
to enable communication with the tool when it is docked in the docking station.
The downhole tool is wireless and driven only by an internal power source. The
tool has a driving unit for driving the tool forward in the casing and an
operational unit, such as a logging unit, a diagnostic unit, a stroker or similar
operational units.
The docking station 211 may be electronically connected to a second display or to
the display of the blowout preventer so that a diver can send operation
instructions to the tool without having to bring the tool out of the well. The tool
can upload or download information or signals to and from the communication
unit 9 of the control unit 8.
The invention also relates to a well intervention system 200 comprising the
intervention module 100 and the remotely operated vehicle 201 for navigating
the intervention module 100 onto the well head 2 or another module subsea.
As shown in Fig. 1, the remotely operated vehicle comprises a camera 202 and a
communication device 203 for communicating with a control unit 8 of the blowout
preventer 1.
The well intervention system 200 further comprises a plurality of sensors 204
arranged in the well for sensing the temperature and/or well fluid pressure inside
the well.
As shown in Fig. 3, the well intervention system 200 comprises a downhole tool
171 having a sensing device 205 for sensing the temperature and/or well fluid
pressure inside the well. When the tool has been down in the well, it connects to
the docking station, and the data measured by the sensing device is uploaded to
the control unit 8 of the blowout preventer 1 so that the data can be transferred
through the display 5 to the ROV of the diver. The diver and/or the ROV comprise
a communication unit which is able to communicate optically with the display and
obtain information about the condition of the well. Furthermore, the downhole
tool has a turbine 179 connected to one end of the tool for recharging the tool
when being in the well by the well fluid flowing past the tool. Before entering the
blowout preventer, the tool has to enter a safety valve 189 which is typically
located 300 metres down the well from the well head.
The display 5 may also comprise a bar code which is readable by the ROV. The
bar code can be an identification tag of the individual well, and/or it can show the
status of the well. The display 5 can have several bar codes, and the control unit
determines from the measurements of the sensors which bar codes to display on
the display.
Fig. 4 shows a well intervention module 100 for performing intervention
operations on subsea or above sea oil wells 101. The intervention module 100 is
launched from a surface vessel 102, e.g. by simply pushing the module 100 out
into the sea from a deck in the back of the vessel 102 or over a side 103 of the
vessel 102. Due to the fact that launching of the intervention module can be
done just by dumping the module 100 into the water, launching is feasible by a
greater variety of vessels, including vessels which are more commonly available.
Thus, the intervention module 100 may also be launched into the water 104 by
e.g. a crane (not shown).
After launch, the intervention module 100 navigates to the well 101 by means of
a navigation means 105 to perform the intervention as shown in Fig. 4 or by
means of a Remotely Operated Vehicle (also called an ROV).
In another embodiment, the navigation means 105 comprises a communication
means allowing an operator, e.g. located on the surface vessel 102, to remotely
control the intervention module 100 via a control system 126. The remote control
signals for the navigation means 105 and the power to the intervention module
100 are provided through a cable 106, such as an umbilical or a tether, which is
spooled out from a cable winch 107.
A well head 120 located on the sea floor, as shown in Figs. 1-5 and 9-13, is the
upper termination of the well 101 and comprises two well head valves 121 and
terminals for connection of a production pipe line (not shown) and for various
permanent and temporary connections. The valves 121 may typically be operated
mechanically, hydraulically or both. At its top, the well head 120 has a protective
cap 123 which must be removed before proceeding with the other intervention
tasks. Typically, subsea well heads 120 or well heads placed above sea are
surrounded by carrying structures 112 to provide load relief for the well head 120
itself when external units are connected. The carrying structure 112 may be
equipped with two, three or four attachment posts 113. The attachment means
111 of the intervention module 100 must be adapted to the specific type of
carrying structure 112 on the well head 120 which the intervention module is to
be docked onto. The attachment means 111 may simply support the intervention
module on the carrying structure 112 by gravity, or it may comprise one or more
locking devices to keep the module 100 in place on the well head 120 after
docking has taken place.
Docking of the intervention module 100 is performed by remote control. The
intervention module 100 is navigated to the well head 120, rotated to be aligned
with the well head structure, and steered to dock on the structure. This may be
done by an ROV or a navigation means 105 having propulsion means and being
provided in the intervention module 100.
In order to gain good vertical manoeuvrability, the navigation means 105 is
provided with a buoyancy system 117 adapted for regulating a buoyancy of the
submerged well intervention module 100. By controlling the buoyancy of the
intervention module 100 while submerged, the module may be made to sink
(negative buoyancy), maintain a given depth (neutral buoyancy) or rise (positive
buoyancy) in the water 104. By using this principle to provide better vertical
manoeuvrability, even heavy objects may be controlled efficiently as exemplified
by submarines utilising such arrangements. In one embodiment, minor vertical
position adjustments may be performed with a vertical propulsion unit 116
suitably oriented.
Providing the well intervention module 100 with substantially increased buoyancy
has the additional effect that it lowers the resulting force exerted on the well
head by the weight of the module 100. Preferably, the intervention module 100
should be maintained at near neutral buoyancy, i.e. be "weightless". This lowers
the risk of rupture of the well head 120, which would otherwise result in a
massive environmental disaster.
To aid this docking procedure, the navigation means 105 comprises a detection
means 109 for detection of the position of the intervention module 100 in the
water 104.
Having an intervention module 100 which is able to manoeuvre independently in
the water 104 reduces the requirements for the surface vessel 102 since the
vessel 102 merely needs to launch the intervention module in the water 104,
after which the module 100 is able to descend into the water under its own
command, thus alleviating the need for expensive, specially equipped surface
vessels, e.g. with large heave-compensated crane systems (not shown).
Furthermore, the lower part of the intervention module 100 weighs more than
the upper part of the intervention module. This is done to ensure that the module
does not turn upside down when submerging so that the bottom and not the top
of the module 100 is facing the well head structure or another module onto which
it is to be mounted.
The intervention module 100 may be remotely controlled by a combined
power/control cable 106, by separate cables or even wirelessly. Since the
intervention module 100 comprises navigation means 105 enabling the module to
move freely in the water, no guide wires or other external guiding mechanisms
are needed to dock the module onto the well head 120. In some events, the
wireline connection 108, 118 between the surface vessel 102 and the module 100
needs to be disconnected, and in these events, the module of the present
invention is still able to proceed with the operation. Furthermore, there is no
need for launching additional vehicles, such as ROVs, to control the intervention
module. This leads to a simpler operation where the surface vessel 102 has a
larger degree of flexibility, e.g. to move away from approaching objects, etc.
The navigation means may have a propulsion unit 115, 116, a detection means
109 and/or a buoyancy system 117. If the navigation means 105 of the module
100 has both a propulsion unit 115, 116 and a detection means 109, the
propulsion unit is able to move the module into place onto another module or a
well head structure on the seabed. If the module 100 only has a buoyancy
system 117, a remotely operated vehicle is still needed to move the module into
position, however the buoyancy system makes the navigation much easier.
Furthermore, when the bottom part of the module 100 weighs more than the top
part, it is ensured that the module always has the right orientation.
The well intervention module 100, 150, 160 according to the invention is formed
by a supporting structure 110 onto which the various subsystems of the
intervention module may be mounted. The supporting structure 110 comprises
attachment means 111 for removably attaching the supporting structure 110 to a
structure 112 of a well head 120 or an additional structure of the well head.
Thus, the attachment means 111 allows the intervention module 100 to be
docked on top of the well head 120. In another embodiment, the attachment
means 111 of a second intervention module 160 can be docked on top of the first
intervention module 150 already docked on the well head 120. The first module is
used for removing the cap of the well head 120, and the second module is used
in the intervention operation for launching a tool into the well 101.
When one intervention module operates in the well 101, another intervention
module is mounted with another tool for performing a second operation in the
well, also called a second run. When the module for the second run is ready to
use, the module is dumped into the water 104 and waits in the vicinity of the well
head 120 ready to be mounted when the "first run" is finished. In this way,
mounting of the tool for the next run can be performed while the previous run is
performed.
As a result, each module can be mounted with one specific tool decreasing the
weight of the module on the well head 120 since a module does not have a big
tool delivery system 170 with a lot of tools and means for handling the tools.
Furthermore, there is no risk of a tool getting stuck in the tool delivery system
170. In addition, they may be more particularly designed for a certain purpose
since other helping means can be built in relation to the tool, which is not
possible in a tool delivery system 170.
As shown in Fig. 5, the intervention module 100 comprises a well manipulation
assembly 125 enabling the intervention module to perform various well
intervention operations needed to complete an intervention job. Furthermore, the
intervention module 100 has a navigation means 105 with a propulsion unit 115,
116 for manoeuvring the module sideways in the water 104. However, the
propulsion unit 115, 116 may also be designed to move the module 100 up and
down. Additionally, the intervention module 100 has a control system 126 for
controlling the well manipulation assembly 125, the navigation means 105 and
the intervention operations, such as a tool 171 operating in the well 101.
The supporting structure 110 is made to allow water to pass through the
structure, thus minimising the cross-sectional area on which any water flow may
act. Thus, the module 100 can navigate faster through the water by reducing the
drag of the module. Furthermore, an open structure enables easy access to the
components of the intervention module 100.
In another embodiment, the supporting structure 110 is constructed, at least
partly, as a tube frame structure since such a construction minimises the weight.
Thus, the supporting structure 110 may be designed from hollow profiles, such as
tubes, to make the structure more lightweight. Such a lightweight intervention
module results in reduced weight on the well head 120 when the module is
docked onto the same, reducing the risk of damage to the well head.
Furthermore, a lightweight intervention module enables easier handling of the
module 100, e.g. while aboard the surface vessel 102.
The supporting structure 110 could be made from metal, such as steel or
aluminium, or a lightweight material weighing less than steel, such as a
composite material, e.g. glass or carbon fibre reinforced polymers. Some parts of
the supporting structure 110 could also be made from polymeric materials.
Other parts of the intervention module 100 could also be made from metals, such
as steel or aluminium, or a lightweight material weighing less than steel, such as
polymers or a composite material, e.g. glass or carbon fibre reinforced polymers.
Such other parts of the intervention module 100 could be at least part of the at
tachment means 111, the well manipulation assembly 125, the navigation means
105, the propulsion unit 115, 116, the control system 126, the detection means
109, the winch 127 un-coiling an intervention medium, e.g. a local wireline, the
tool exchanging assembly, the tool delivery system 170, the power storage
system 119 or similar means of the intervention module 100.
The supporting structure 110 may also be made of hollow profiles enclosing gas,
providing further buoyancy to the module 100 when submerged into the sea.
Fig. 6 shows how the supporting structure 110 of an embodiment of the
intervention module fully contains the navigation means 105, the control system
126 and the well manipulation assembly 125 within the outer form of the frame.
Thus, the supporting structure 110 protects the navigation means 105, the
control system 126 and the well manipulation assembly 125 from impact with
e.g. the sea floor or objects on the surface vessel 102. Therefore, the
intervention module 100 is able to withstand being bumped against the sea floor
when it descends, and to lay directly on the sea floor, e.g. when waiting to be
docked on the well head 120.
In order to perform a well intervention, a cap of the well head 120 has to be re
moved, and subsequently, a tool is launched into the well 101 as shown in Fig. 9.
Therefore, the first intervention module 150 to dock onto the well head 120 is a
module where the well manipulation assembly 125 comprises means for
removing a protective cap 123. In a next intervention step, a second intervention
160 module comprising means for deploying a tool 171 into the well 101 is
docked onto the first intervention module 150. The first 150 and the second 160
module may, in another embodiment, be comprised in one module as shown in
Figs. 5 and 10.
The detection means 109 uses ultrasound, acoustic means, electromagnetic
means, optics or a combination thereof for detecting the position of the module
100 and for navigating the module onto the well head 120 or another module.
When using a combination of navigation techniques, the detection means 109 can
detect the depth, the position and the orientation of the module 100. Ultrasound
may be used to gauge the water depth beneath the intervention module 100 and
to determine the vertical position, and at the same time, a gyroscope may be
used to determine the orientation of the intervention module. One or more
accelerometers may be used to determine movement in a horizontal plane with
respect to a known initial position. Such a system may provide full position
information about the intervention module 100.
In another embodiment, the detection means 109 comprises at least one image
recording means, such as a video camera. Furthermore, the image recording
means comprises means for relaying the image signals to the surface vessel 102
via the control system 126. The video camera is preferably oriented to show the
attachment means 111 of the intervention module 100 as well as the well head
120 during the docking procedure. This enables an operator to guide the
intervention module 100 by vision, e.g. while the module is being docked on the
well head 120. As shown in Fig. 5, the image recording means may be mounted
on the supporting structure 110 of the intervention module 100 in a fixed
position, or be mounted on a directional mount which may be remotely controlled
by an operator. Evident to the person skilled in the art, the vision system may
comprise any number of suitable light sources to illuminate objects within the
optical path of the vision system.
In another embodiment, the image recording means further comprises means for
analysing the recorded image signal, e.g. to enable an autonomous navigational
system to manoeuvre the intervention module 100 by vision.
To achieve better manoeuvrability of the intervention module 100 while
submerged, it must be able to maintain its vertical position within the water 104,
and simultaneously be able to move in the horizontal plane and be able to rotate
around a vertical axis 114, allowing the attachment means 111 to be aligned with
the attachment posts 113 of the carrying structure 112 of the well head 120 for
docking.
Horizontal manoeuvrability as well as rotation may be provided by one or more
propulsion units 115, 116, such as thrusters, water jets or any other suitable
means of underwater propulsion. In one embodiment, the propulsion units 115,
116 are mounted onto the intervention module 100 in a fixed position, i.e. each
propulsion unit 115, 116 has a fixed thrust direction in relation to the
intervention module 100. In this embodiment, at least three propulsion units
115, 116 are used to provide movability of the module 100. I n another
embodiment, the thrust direction from one or more of the propulsion units 115,
116 may be controlled, either by rotating the propulsion unit itself or by directing
the water flow, e.g. by use of a rudder arrangement or the like. Such a setup
makes it possible to achieve full manoeuvrability with a fewer number of
propulsion units 115, 116 than necessary if the units are fixed to the intervention
module 100.
The intervention module 100 may be remotely operated, be operated by an
autonomous system or a combination of the two. For example, in one
embodiment, docking of the module is performed by a remote operator, but an
autonomous system maintains e.g. neutral buoyancy while the module 100 is
attached to the well head 120. The buoyancy system 117 may furthermore
provide means for adjusting the buoyancy to account for changes in density of
the surrounding sea water, arising from e.g. changes in temperature or salinity.
Figs. 7 and 8 show two different embodiments of buoyancy systems 117.
Generally, the buoyancy system 117 must be able to displace a mass of water
corresponding to the total weight of the intervention module 100 itself. For
example, if the module weighs 30 tonnes, the mass of the water displaced must
be 30 tonnes, roughly corresponding to a volume of 30 cubic metres, to establish
neutral buoyancy. However, not the full volume will need to be filled with water
for the module 100 to descend since this would make the module sink very
quickly. Therefore, a part of the buoyancy system 117 may be arranged to
permanently provide buoyancy to the module while another part of the buoyancy
system 117 may displace a volume to adjust the buoyancy from negative to
positive. The permanent buoyancy of the buoyancy system 117 can be provided
by a sealed off compartment of a displacement tank 130 filled with gas or a
suitable low-density material, such as syntactic foam. The minimum buoyancy
will depend on the drag of the module 100 as it descends. Similarly, the
maximum buoyancy obtainable should be selected to enable the module 100 to
ascend with a reasonably high speed to allow expedient operations, but not faster
than safe navigation of the module 100 mandates.
Fig. 7 shows a buoyancy system 117 comprising a displacement tank 130 which
may be filled with seawater or with a gas, such as air. To increase the buoyancy
of the module 100, gas is introduced into the tank 130, displacing seawater. To
lower the buoyancy, gas is let out of the tank 130 by a control means 131, thus
letting seawater in. The control means 131 for controlling the filling of the tank
with sea-water may simply be one or more remotely operated valves letting gas
in the tank 130 escape. The tank may have an open bottom, or it may completely
encapsulate the contents. In case of an open tank, water will automatically fill up
the tank 130 when the gas escapes, and in case of a closed tank, an inlet valve is
needed to allow water to enter the tank 130.
Fig. 8 shows a buoyancy system 117 comprising a number of inflatable means
140 which may be inflated by expansion means 132. Any number of inflatable
means 140 may be envisioned, e.g. one, two, three, four, five or more. The
inflatable means 140 may be formed as balloons, airtight bags or the like, and
may be inflated to increase buoyancy, e.g. when the intervention module 100 is
to ascend to the sea surface after the intervention procedure. The expansion
means 132 may comprise compressed gas, such as air, helium, nitrogen, argon,
etc. Alternatively, the gas needed for inflation of the inflatable means 140 is
generated by a chemical reaction, similar to the systems used for inflation of
airbags in cars. The inflatable means 140 must be fabricated from materials
sufficiently strong to withstand the water pressure found at the desired
operational depth. Such materials could be a polymer material reinforced with
aramid or carbon fibres, metal or any other suitable reinforcement material. A
buoyancy system 117 as shown in Fig. 8 may optionally comprise means for
partly or fully releasing gas from an inflatable means 440 or even for releasing
the whole inflatable means 140 itself.
In one embodiment, the intervention module 100, 150, 160 has a longitudinal
axis parallel to a longitudinal extension of the well 101, and the module is weight
symmetric around its longitudinal axis. Such symmetric weight distribution
ensures that the intervention module 100 does not wrench the well head 120 and
the related well head structure when docked onto the well head.
In another embodiment, the buoyancy system 117 is adapted to ensure that the
centre of buoyancy onto which the buoyant force acts is located on the same
longitudinal axis as the centre of mass of the intervention module 100, and that
the centre of buoyancy is located above the centre of mass. This embodiment
ensures a directional stability of the intervention module 100.
As shown in Fig. 5, the intervention module 100, 150, 160 comprises a power
system 119 which is positioned on the module. The power system 119 can be in
the form of a cable 106 connected to the surface vessel 102 or in the form of a
battery, a fuel cell, a diesel current generator, an alternator, a producer or
similar local power supplying means. In one embodiment, the power system 119
powers the well manipulation assembly 125 and/or other means of the module
using hydraulic, pressurised gas, electricity or similar energy. By providing a local
power supplying means or a reserve power to the intervention module 100, the
intervention module is able to release itself from the well head 120 or another
module and, if needed, bring up a tool in the well 101. This, at least, enables the
intervention module 100 to self-surface, should such damage or other
emergencies occur. In another embodiment, the local power supplying means
allows the intervention module 100 to independently perform parts of the
intervention procedure without an external power supply.
In some embodiments, the power system 119 comprises a power storage system
133 for storage of energy generated from intervention operations, such as
submersion of an operational tool 171 into the well 101. In one such
embodiment, the power storage system 133 comprises a mechanical storage of
the energy released as the tool 171 is lowered within the well 101, which stored
energy can be used for a later hoisting of the tool. The power storage system 133
may comprise a mechanical storage means being any kind of a tension system,
pneumatic storage means, hydraulic storage means or any other suitable
mechanical storage means. By providing the intervention module 100 with a
power storage system 133, the required capacity of e.g. electrical power needed
for operations is lowered due to the reuse of stored energy. Of course, the
intervention module 100 may comprise any combination of two or more power
supplying means.
Furthermore, the power system 119 of the intervention module 100 may be pow
ered by at least one cable 106 for supplying power from above surface to the
intervention module. The cable 106 is detachably connected to the intervention
module 100 in a connection 108 enabling easy separation of the cable from the
intervention module in the event that the surface vessel 102 needs to move. This
is shown in Fig. 9 where the cable 106 has just been detached. The cable 106
may be adapted to supply the intervention module 100 with electrical power from
the surface vessel 102 and may e.g. be provided as an umbilical or a tether.
Communication with the surface vessel 102 enables the intervention module 100
to be remotely operated and to transmit various measurement and status data
back to the vessel. The intervention module 100 may communicate by wire or
wirelessly with the surface vessel 102 or with other units, submerged or on the
surface. The communication wire may be a dedicated communication line
provided as a separate cable or as a separate line within a power cable, or a
power delivery wire connection, such as a power cable. In another embodiment,
as shown in Figs. 11 and 12, the intervention module 100 comprises wireless
communicational means, such as radio frequency communication, acoustic data
transmission, an optical link or any other suitable means of wireless underwater
communication. Communication may take place directly with the intended
recipient or by proxy, i.e. intermediate sender and receiver units, such as relay
devices 190. The communication means may enable bi or unidirectional
communication communicating such data from the intervention module 100 as a
video feed during the docking procedure, position, current depth reading, status
of subsystems or other measurement data, e.g. from within the well 101.
Communication to the intervention module 100 could e.g. be requests for return
data, manoeuvring operations, control data for the well manipulation assembly,
i.e. controlling the actual intervention process itself, etc.
In one embodiment, the control system 126 comprises both wired and wireless
communicational means, e.g. so that a high-bandwidth demanding video feed
may be transmitted by wire until the intervention module 100 is docked on the
well head 120. When the module has been docked, less bandwidth-demanding
communications, such as communication needed during the intervention itself,
may be performed wirelessly by means of relay devices 190.
If the communication wire, e.g. combined with a power cable, is released from
the intervention module 100, no physical connection is required between any
surface or submerged vessel and the intervention module due to the fact that the
intervention module may still be controlled by the wireless connection 180, 191.
Thus, in one embodiment, the control system 126 comprises disconnection
means 108, for disconnection of the cable for providing power to the system, a
wireline for connection of the intervention module 100 to a vessel 102, or the
attachment means 111. Subsequent to the disconnection, the intervention
module 100 continues to function from its own power supply. When the cable has
been released from the intervention module 100 and recovered on the surface
vessel 102, the vessel is free to navigate out of position, e.g. to avoid danger
from floating obstacles, such as icebergs, ships, etc.
As mentioned, in order to perform the actual intervention tasks, the module 100
comprises a well manipulation assembly 125 which may be a cap removal means
134 or a tool delivery system 170. The tool delivery system 170 comprises at
least one tool 171 for submersion into the well 101 and a tool submersion means
172 for submerging the tool into the well 101 through the well head 120. Having
a tool submersion means 172 of the tool delivery system 170 mounted on the
module 100 makes handling of the tool independent of the surface vessel 102.
This ensures that the well head 120 is not subject to any undue strain or torque
from e.g. a long wire line or guide wires extending from the well head 120 to the
surface vessel 102. Such strain or torque is highly unwanted since it may
ultimately lead to rupture of the well head 120, which could potentially lead to a
massive environmental disaster.
To connect the well manipulation assembly 125 to the well head 120, the
assembly further comprises at least one well head connection means 173 and a
well head valve control means 174 for operating at least a first well head valve
121 for providing access of the tool into the well 101 through the well head
connection means 173. Well heads typically have either mechanically or
hydraulically operated valves. Thus, the well head valve control means 174,
controlled by the intervention module control system 126, comprises means for
operating the valve controls, such as a mechanical arm or a hydraulic connection,
and a system for delivering the required mechanical or hydraulic force to the
valve controls.
The tool submersion means 172 may be a winch 127 uncoiling an intervention
medium, such as a local wireline, a braided line or a lightweight composite cable,
connected to the tool for submerging the tool into the well 101 and coiling the
intervention medium when pulling the tool up from the well.
Well interventions commonly require tools to be submerged into the well 101 by
wireline, coiled tubing, etc. In the event that part of the well 101 is not
substantially vertical, a downhole tractor can be used as a driving unit to drive
the tool all the way into position in the well. A downhole tractor is any kind of
driving tool capable of pushing or pulling tools in a well downhole, such as a Well
Tractor®.
The supporting structure 110 is a frame structure having a height, a length and a
width corresponding to the dimensions of a standard shipping container. A
shipping container may have different dimensions, such as 8-foot (2.438 m) cube
(2.44 mx2.44 mx2.44 m) units used by the United States' military, or later st an
dardised containers having a longer length, e.g. 10-foot (3.05 m), 20-foot (6.10
m), 40-foot (12.19 m), 48 foot (14.63 m) and 53 foot (16.15 m) lengths.
European and Australian containers may be slightly wider, such as 2 inches (50.8
mm).
The connection means 173 typically comprises a lubricator 178 for connecting to
the well head 120 and for taking up the tool when it is not deployed.
Furthermore, the connection means 173 typically comprises a grease injection
head for establishing a tight seal around the tool submersion means 172 while
still allowing the tool submersion means to pass through the sealing for moving
the tool in and out of the well 101. In one embodiment, the control system 126
comprises disconnection means 108 for disconnection of the well head connection
means 173 enabling the lubricator 178 to be disconnected from the well head
120. In case of an emergency, the tool comprises a release device for releasing
the cable from the tool in the event that the tool gets stuck downhole.
In a further embodiment, the power system 119 has an amount of reserve power
large enough for the control system 126 to disconnect the well head connection
means 173 from the well head 120, the cable for providing power from the power
system 119, the wireline from the module, and/or the attachment means 111
from the well head structure. In this way, the intervention module 100 can
resurface even if a cable needs to be disconnected, e.g. due to an oncoming risk
to the surface vessel 102. In one embodiment, the required reserve power may
be provided by equipping the intervention module 100 with a suitable number of
batteries enabling the required operations.
The well intervention module 100, 150 may also comprise two or more tools
which are stored in a tool exchanging assembly while the tools are not deployed.
The tool exchanging assembly, controlled by the control system 126, enables tool
exchange between two or more tools, allowing multiple intervention operations
requiring different tools to be performed by the same module without the need
for the module to resurface, or other outside influence.
A typical intervention operation requires at least one additional configuration of
the well manipulation assembly 125, besides the configuration with a tool. As
mentioned, the additional configuration can be a cap removal assembly 151
comprising a cap removal means 134, as shown in Fig. 9. Such cap removal
means 134 may be adapted to pull or unscrew the protective cap 123 of the well
101, depending on the design of the well head 120 and/or the protective cap
123. Furthermore, the cap removal means 134 may be adapted to vibrate the
cap 123 to loosen debris and sediments which may have been deposited on the
cap.
As mentioned, the cap removal assembly 151 may be mounted on a special intervention
module dedicated to being a cap removal module 150. This cap removal
module 150 may be adapted to allow subsequent intervention modules 100, 160
to be docked in extension to itself when attached to the well head 120. The
module shown in Fig. 9 comprises a receiving means 155 towards the top of the
supporting structure 110 where the receiving means 155 is adapted to receive
the attachment means 111 of a subsequent intervention module 100, 160. In the
embodiment shown in Fig. 9, the cable has now been detached from the module
100 so as to be recovered by the surface vessel 102. The control system of the
cap removal module 150 is now communicationally connected to the surface
vessel 102 by a wireless link.
As shown in Fig. 12, some embodiments of the well intervention system 100
comprise at least one autonomous communication relay device 190 for wirelessly
receiving waterborne signals 180 from the intervention module 100, 150, 160,
converting the signals from the module 100 into airborne signals 191 and
transmitting the airborne signals to the remote control means 192, and vice
versa to receive and convert signals from the remote control means and transmit
the converted signals to the intervention module 100.
In an embodiment, the autonomous communication relay device 190 is designed
as a buoy and has a resilient communication cable 194, 199 hanging underneath.
The communication relay device 190 may be a small vessel, a dinghy, a buoy or
any other suitable floating structure. Preferably, the relay device 190 comprises
navigation means 105 enabling it to be remotely controlled from the surface
vessel 102, e.g. to maintain a specific position. Also, in some embodiments, the
relay device 190 comprises means for detecting its current position, such as a
receiver 193 for the Global Positioning System (GPS).
In Fig. 11, the resilient communication cable 194, 199 hangs underneath the
vessel 102 where the end of the cable has means for communicating with a first
100, 150 and a second 100, 160 module.
Airborne communication to and from the intervention module 100 is relayed
between underwater communicational means and above-surface
communicational means, such as antennas 192, as seen in Fig. 12. Underwater
communication means may be a wire which is connected to the intervention
module 100 (see Fig. 13), or it may be a means for wireless underwater
communication, e.g. by use of radio frequency signals or optical or acoustic
signals. If wireless communication is used, the communicational relay device 190
may be adapted for lowering the underwater communicational means far down
into the water, e.g. to reach depths of 10-100%, alternatively 25-75%, or even
40-60% of the water depth. This limits the required underwater wireless
transmission distance as it may be required to circumvent the excessively large
transmission losses of electromagnetic radiation in sea water. Airborne
communication may take place with the surface vessel 102 or with e.g. a remote
operations centre.
Fig. 13 shows an embodiment where the underwater communication means of
the relay device 190 is a communication wire 199 which is connected to the
intervention module 100, and which may be pulled out from the relay device 190
as the intervention module descends. The relay device 190 may be provided with
means for spooling out the wire 199, or the wire may simply be pulled from a
spool by the weight of the intervention module 100 as the module descends. The
wire 199 may be hoisted either by electromechanical means, such as a winch, or
by purely mechanical means, such as a tension system.
A well intervention utilising intervention modules according to the present
intervention thus comprises the steps of positioning a surface vessel 102 in
vicinity of the well head 120, connecting a well intervention module 100 to a
wireline on the vessel, dumping the well intervention module 100 into the sea
from the surface vessel 102 by pushing the module over an edge of the vessel,
controlling the navigation means 105 on the intervention module 100,
manoeuvring the module 100 onto the well head 120, connecting the module 100
onto the well head 120, controlling the control system 126 to perform one or
more intervention operations, detaching the module 100 from the well head 120
after performing the operations, and recovering the module 100 onto the surface
vessel 102 by pulling the wireline. The surface vessel 102 does not need to be
accurately positioned over the well head 120 since the module 100 navigates
independently and is not suspended from the vessel. Furthermore, the often
critical prior art procedure of deploying the intervention module into the water is
significantly simplified since the module 100 may merely be pushed over the side
103 of the surface vessel 102. This enables deployment of an intervention
module 100 in rough conditions which would otherwise be prohibitive for
intervention operations. Also, since the module 100 is remotely operated, there is
no need for deploying additional vehicles, such as ROVs, thus further simplifying
the intervention operation.
In some embodiments of the intervention method according to the invention, one
or more additional well intervention modules are dumped sequentially after or
simultaneously with the first module. As the first intervention module performs
its designated operations, the next intervention module may be prepared on the
surface vessel 102 and launched into the sea to descend towards the well head
120. When the first intervention module has performed its operations, it may
return to the surface by its own means while the second intervention module
waits in the vicinity of the well head 120 to be docked on the well head. By
having an awaiting second intervention module, a quick change from one
intervention module to the next is possible, compared to a situation where
multiple intervention modules need to be lowered by crane onto the well head,
e.g. via a set of guide wires. In that case, more time is needed to perform the
intervention.
In another embodiment of the well intervention system 200, the system
comprises the intervention module 100 described above as well as a remote
operating centre. This is particularly useful when working with well heads 2
placed above water as it allows for communication to take place without using
bouys and simply through normal air communication means, such as satellites
etc.
The invention further relates to a well system 500 for launching a downhole tool
171 through a well head 2. The well system 500 comprises a launcher system
210 comprising a lubricator 178 closed off at a first end by a blind cap, a
downhole tool 171 arranged in the lubricator, a lubricator valve 205 arranged so
that it closes off the lubricator at a second end opposite the first end, and a
connector 212 for being connected to a blowout preventer or a well head. The
system 210 further comprises a well having a well head and a safety valve
arranged at least 10 metres, preferably at least 100 metres, and more preferably
at least 250 metres down in relation to the well head. The well further comprises
a docking station enabling connection with an operational tool 12 in the well for
charging or recharging power and transmitting and receiving information and
data, such as control instructions regarding the next scheduled operation or
logging.
The well system 500 may further comprise the blowout preventer 1, the launcher
system or the intervention module 100 and a remote operating centre, enabling a
well system having a well head 2 above water to transmit data to and from the
operating centre through the control unit or display to a downhole tool.
The transmission of data to and/or from the remote operating centre may take
place through any form of wired or wireless communication, such as through
satellites, etc.
The downhole tool 171 may comprise an inductive coupling for charging or
recharging power and transmitting and/or receiving information. The docking
station may in the same way comprise an inductive coupling enabling the tool
171 to connect to the docking station for charging or recharging power and
transmitting and/or receiving information.
The downhole tool 171 may also comprise a rotating device, such as a turbine,
engaged in the fluid flow during production for charging or recharging power.
In Fig. 14, the display is shown comprised in a housing 20 which seals off a space
2 1 in which the display is arranged. The housing 20 is made of a material
thermally and/or pressuringly isolating the display from an outside temperature
and/or pressure so that the temperature and/or pressure in the space is
maintained within a predetermined range.
In Figs. 15 and 16, it is shown that the housing comprises a face plate 27 made
of a transparent material which is arranged pressing towards a sealing element
29 to seal off the space 21. In the housing 20, an environmental control device
22 for controlling the temperature and/or pressure is arranged. In Fig. 15, the
environmental control device 22 comprises a heat exchanger device 24 for
keeping the temperature of the display within a predetermined temperature
range by cooling or heating the fluid 28 comprised in the space 21.
In Fig. 16, the environmental control device comprises a chamber 25 comprising
gas and a valve 26 for letting the gas into the space 2 1 to increase the pressure
in the space surrounding the display or letting gas from the space into the
chamber to decrease the pressure within the space 21. The environmental control
device 22 may also comprise an accumulator for accumulating pressure and/or
temperature differences within the housing 20.
As shown in Fig. 15, the housing is filled with liquid 28 for controlling the
temperature and/or the pressure surrounding the display. The liquid may be a
cooling agent which is easy to cool or heat in order to maintain the temperature
and/or pressure within a predetermined range in order to keep the digital display
functioning. The processing unit 23 may be arranged inside the housing and thus
protected from high temperature and/or pressure or high temperature and/or
pressure changes using the same environmental control device as the digital
display.
The display itself may also be filled with the fluid 28 and the elements inside the
display such as the circuit board may be sealed by a sealing wax or lacquer to
electrically isolate the electrical connections in the display.
The display may further comprise a simple keyboard connected with the
processing unit and sealed by means of a rubber cover. Hereby, a field engineer
or diver can press the keys to change screen display in order to get more
information.
The processing unit may be arranged in the blowout preventer, in the
intervention module or in the well and connected to the display for
communicating information such as if the valves are in safe mode. Thus, the
processing unit can serve as a black box known from aeroplanes in connection
with crashes.
In the event of a storm or a hurricane, such as Katrina, the connection to the
operational tool may be disconnected very quickly so that the tool operating
downhole is not yet in the lubricator ready to be disconnected from the well head
or blowout preventer. Thus, the position of the primary barrier is not known
when going down to check on the situation after the hurricane has passed. In
order to avoid a Deep Water Horizon situation, the positions of the valves forming
the "lid" and primary barrier of the well need to be known before entering the
well. By having a display, all kinds of information of the condition of the well can
be read out through the display so that a third-party operation company can
resume the operation without making a catastrophe. The display may have some
kind of recognition or access key so that not all operators are allowed to view
that information.
Other kind of information to be displayed is the position of the tool such as the
downhole tractor 171, the position of the safety valve, the lubricator valves, the
blowout preventer valve/rams, any activated alarms, the time of the last position
or measurement, the battery time of the tool, the operation steps performed by
the tool, etc.
By having a downhole tool 171, such as a downhole tractor propelling itself and
other tools forward in the well, data can be communicated quicker to the surface
than in prior art well communication systems as the downhole tractor is capable
of propelling itself up to the surface with a huge data quantity faster than the
same amount of data can be transferred from the tool in the well to the surface
using known communication systems.
A flat display panel is also called a flatscreen or a CRT screen and examples of
flat display panels are Plasma displays, Liquid crystal displays (LCDs), Organic
light-emitting diode displays (OLEDs), Light-emitting diode displays (LED),
Electroluminescent displays (ELDs), Surface-conduction electron-emitter displays
(SEDs), or Field emission displays (FEDs) also called Nano-emissive displays
(NEDs).
By a light-emitting diode display is meant a display using light-emitting diode for
making readable letters or other information. By a vacuum fluorescent display is
meant a display comprising vacuum fluorescence for displaying information. By a
liquid crystal display is meant a display comprising liquid crystal for displaying
information. By an electroluminescent display is meant a display comprising
electroluminescence for displaying information. By a thin-film transistor display is
meant a display comprising a thin-film transistor for displaying information. By a
surface-conduction electron-emitter display is meant a display comprising
surface-conduction electron-emitter for displaying information. By a nanocrystal
display is meant a display comprising nanocrystal for displaying information.
By fluid or well fluid is meant any kind of fluid that may be present in oil or gas
wells downhole, such as natural gas, oil, oil mud, crude oil, water, etc. By gas is
meant any kind of gas composition present in a well, completion, or open hole,
and by oil is meant any kind of oil composition, such as crude oil, an oilcontaining
fluid, etc. Gas, oil, and water fluids may thus all comprise other
elements or substances than gas, oil, and/or water, respectively.
By a casing is meant any kind of pipe, tubing, tubular, liner, string etc. used
downhole in relation to oil or natural gas production.
In the event that the tool is not submergible all the way into the casing, a
downhole tractor can be used to push the tool all the way into position in the
well. A downhole tractor is any kind of driving tool capable of pushing or pulling
tools in a well downhole, such as a Well Tractor®.
Although the invention has been described in the above in connection with
preferred embodiments of the invention, it will be evident for a person skilled in
the art that several modifications are conceivable without departing from the
invention as defined by the following claims.
Claims
1. A blowout preventer (1) for being mounted on a well head (2), comprising:
- a plurality of valves (3, 4) arranged in fluid communication with each other,
connected and forming a tubular pipe,
wherein the blowout preventer further comprises a display (5) visible from
outside the blowout preventer.
2. A blowout preventer according to claim 1, wherein the display is a digital
display.
3. A blowout preventer according to claim 1, further comprising a housing (20)
sealing off a space (21) in which the display is arranged.
4. A blowout preventer according to claim 3, wherein the housing is made of a
material thermally and/or pressuringly isolating the display from an outside
temperature and/or pressure so that the temperature and/or pressure in the
space is maintained within a predetermined range.
5. A blowout preventer according to claims 2-4, wherein the housing
comprises an environmental control device (22) for controlling the temperature
and/or pressure within the housing.
6. A blowout preventer according to any of the proceeding claims, wherein the
display is connected with a processing unit (23) for displaying information on the
display.
7. A blowout preventer according to any of the preceding claims, further
comprising a storing device (6) for storing measurements and received or
transmitted signals or recorded data.
8. A blowout preventer according to any of the preceding claims, wherein the
display is a flat display panel, a light-emitting diode display, a vacuum
fluorescent display, a liquid crystal display, an electroluminescent display, a thinfilm
transistor display, a surface-conduction electron-emitter display, or a
nanocrystal display.
9. A blowout preventer according to any of the preceding claims, further
comprising a control unit (8) comprising the storage device, and a
communication unit (9) for communicating with and transmitting and/or receiving
data to and/or from the display or monitor.
10. A blowout preventer according to any of the preceding claims, wherein the
control unit comprises a receiving and/or transmitting unit enabling the control
unit to transmit data to and from a remote operating centre.
11. A blowout preventer according to any of the preceding claims, further
comprising a sensor (10) for sensing the temperature and/or well fluid pressure
inside the well.
12. A blowout preventer according to any of the preceding claims further
comprising a docking station (11) enabling an operational tool (12) in the well to
connect to the blowout preventer and be charged or recharged, or to upload or
download information or signals to and from the communication unit.
13. A launcher system (210) for launching a downhole tool through a well head,
comprising:
- a lubricator (178) closed off at a first end by a blind cap,
- a downhole tool (171) arranged in the lubricator,
- a lubricator valve (205) arranged to close off the lubricator at a second end
opposite the first end,
- a shear ram valve (206) connected with the lubricator valve, and
- a connector (212) for connecting the launcher system to a blowout preventer or
a well head.
14. A launcher system according to claim 13, further comprising a digital
display arranged inside a fluid-tight housing and visible from outside the system.
15. A launcher system according to any of claims 13-14, further comprising a
docking station (211) arranged at the first end of the lubricator to enable the tool
to connect with the docking station and be charged, recharged, and/or
communicate data to and/or from the tool.
16. A launcher system according to any of claims 13-15, wherein the downhole
tool is wireless and driven only by an internal power source in the downhole tool.
17. A launcher system according to any of claims 13-16, wherein the tool
comprises an inductive coupling for charging or recharging power and
transmitting and/or receiving information.
18. A launcher system according to any of claims 13-17, wherein the tool
comprises a rotating device, such as a turbine, engaged in the fluid flow during
production for charging or recharging power.
19. A well intervention module (100) for performing well intervention
operations in a well, comprising a blowout preventer according to any of claims
1-12, and a supporting structure (110).
20. A well intervention module (100) for performing well intervention
operations in a well, comprising a launcher system according to any of claims 13-
18, and a supporting structure (110).
21. A well intervention module according to claim 19 or 20, further comprising:
- an attachment means (111) for removably attaching the supporting structure to
a structure of a well head or an additional structure, and
- a well manipulation assembly (105).
22. A well intervention module according to claim 19 or 21, further comprising
a digital display (5) arranged inside a fluid-tight housing (20) and visible from
outside the system.
23. A well intervention system (200) comprising
- a well intervention module (100) according to any of claims 19-22, and
- a remotely operated vehicle (201) for navigating the intervention module onto
the well head or another module.
24. A well intervention system according to claim 23, wherein the tool
comprises an inductive coupling for charging or recharging power and
transmitting and/or receiving information, e.g. through the docking station.
25. A well intervention system according to any of claims 23-24, wherein the
tool comprises a rotating device, such as a turbine, engaged in the fluid flow
during production for charging or recharging power, e.g. through the docking
station.
26. A well intervention system according to any of claims 23-25, further
comprising a plurality of sensors (204) arranged in the well for sensing the
temperature and/or well fluid pressure inside the well.
27. A well intervention system according to any of claims 23-26, further
comprising a downhole tool (171) having a sensing device (205) for sensing the
temperature and/or well fluid pressure inside the well.
28. A well system (500) for launching a downhole tool through a well head,
comprising:
- a launcher system (210) according to any of the claims 13-18,
- a well comprising a safety valve arranged at least 10 metres down in relation to
the well head,
wherein the well further comprises a docking station enabling connection to an
operational tool (12) in the well for charging or recharging power and
transmitting and receiving information and data, such as control instructions
regarding the next scheduled operation or logging.
29. A well system according to claim 28, wherein the tool, such as a downhole
tractor, propelling itself forward in the well, is capable of propelling itself up to
the surface with a certain amount of data quantity faster than the same amount
of data can be transferred from the tool in the well to the surface by a
communication cable.
30. A well system according to claim 28 or 29, wherein the tool comprises an
inductive coupling for charging or recharging power and transmitting and/or
receiving information.
31. A well system according to any of claims 28-30, wherein the tool comprises
a rotating device, such as a turbine, engaged in the fluid flow during production
for charging or recharging power.
32. Use of the blowout preventer according to any of claims 1-12, a launcher
system according to any of claims 13-18 or a well intervention module according
to any of claims 19-22 for performing a well intervention.