[0001] The present invention relates to a system and a method for providing foundations
for underwater (subsea) structures using one or more tension anchors to fix the structure
to the seabed. Such underwater foundations are required for fixing and supporting
apparatus onto the bed of the sea, river or estuary and are generally disclosed in
US 7 380 614 B1. Such apparatus positioned on the bed of the sea, river or estuary may comprise energy
conversion systems including, but not limited to, tidal stream turbines.
[0002] Reference to the term "seabed" throughout this description is to be understood to
include any underwater floor bed.
[0003] In particular, the present invention relates to methods for the installation of subsea
foundations to the seabed to which a wide variety of subsea apparatus can be attached
and most particularly, the present invention provides post tensioned anchored foundations
installed using submergible robotic equipment.
[0004] The system and method of the present invention can be used with any type of underwater
bed anchorage. However, the present invention will be described and discussed herein
with reference to its main application which is providing foundations for water current
energy conversion systems, such as tidal energy conversion systems and wave energy
conversation systems.
BACKGROUND TO THE INVENTION
[0005] With the continued development and commercialisation of devices designed to recover
energy from marine environments such as tidal stream turbines and wave energy conversion
devices, there is an urgent requirement for the development of new techniques and
equipment to facilitate the quick, safe and cost effective installation of devices
and their foundations on the seabed. This presents particular technical problems in
the marine environments where these devices are to be installed especially in the
areas of strong tidal motion where devices such as tidal stream turbines are installed.
[0006] The installation techniques that have, until now, been used to install the current
single larger scale demonstrator devices fall into two main groups, namely, oil and
gas technology; and marine civil engineering technology. While there is undoubtedly
equipment that can and has been used from the oil and gas industry, the costs involved
are prohibitive for commercial deployment, given commercial return from the energy
output over the life time of the installation.
[0007] In the prior art, when installing subsea structures for the Oil and Gas and Renewable
Energy industries, typically, underwater piled foundations are used and these are
installed by equipment operated from surface vessels. Alternatively, heavily ballasted
structures are used. This requires specialised vessels for long periods of time which
is prohibitively expensive.
[0008] The pile locations have to be accurate to allow prefabricated foundation units to
be installed. This accuracy has to be achieved tens of metres below the sea surface.
[0009] In locations of significant overburden or where the bedrock is weak or fractured,
the pile length and diameter has to be increased, requiring deeper and wider holes
to be drilled into the seabed, and consequentially longer and larger diameter piles.
[0010] Marine civil engineering equipment has been used but this equipment is more suited
for the sheltered coastal environment for which it has been designed. The challenging
environmental conditions prevalent at the locations of the more energetic marine energy
sites have for the most part been avoided, up to now, because of the difficulty and
high cost involved in installing and maintaining infrastructure on these sites. Furthermore,
obtaining good accurate site investigation information from these prospective sites
is both difficult and costly.
[0011] The present invention seeks to overcome the disadvantages of the prior art.
[0012] It is a purpose of the present invention to provide a system for installing a foundation
for a subsea structure as detailed in claim 1. Also provided is a method for installing
foundations in the seabed according to claim 13. Advantageous features are provided
in the dependent claims. The present invention accordingly provides a system for installing
a foundation for a subsea structure, the system for installing a foundation for subsea
structures comprising at least one tension anchor and means for embedding said at
least one tension anchor into the seabed.
[0013] The system for installing a foundation to a subsea structure preferably comprises
a foundation frame which is provided with anchoring means, the foundation frame being
adapted to support and be removably connected with apparatus such as energy conversion
apparatus and the anchoring means, in use, being embedded in the seabed. Preferably,
the system comprises control means wherein the control is carried out remotely from
the installation, the control means being connected to the installation.
[0014] Advantageously, this system for the installation of a subsea foundation comprises
an installation and drilling frame carrying drilling means; the installation and drilling
frame being removably connectable to the foundation frame.
[0015] The present invention provides a system and a method for the installation of a subsea
foundation including at least one tension anchor in the seabed and a foundation frame
to which a wide variety of structures/apparatus can be attached.
[0016] Thus, the foundation frame may be a single tension anchored foundation frame or multiple
tension anchored foundation frame for providing a foundation to subsea structures
which in use, are mounted onto the foundation frame which in turn is anchored into
the seabed by the single or multiple tension anchors provided on the foundation frame.
[0017] To achieve the accurate positioning of the tension anchors, the prefabricated foundation
frame structure itself is used as the locating template for the drilling equipment.
[0018] The tension anchor preferably comprises a hollow self-drilling anchor or a tubular
anchor, preferably incorporating a detachable drill bit. Advantageously, the hollow
anchor also includes a drive means, optionally comprising a drive shoe.
[0019] Furthermore in accordance with the system of the present invention, the tension anchor(s)
is/are installed using robotic underwater installation equipment connected to a support
vessel by umbilical cables.
[0020] Furthermore, the type, diameter and/or length of the anchor bar, the anchoring material
and the bond length into the seabed can be adjusted to suit a wide variety of seabed
conditions.
[0021] Furthermore, an advantage of the system and method of the present invention is that
the integrity of the anchor can be tested, proof loaded and post tensioned with loads
greater than the maximum design load so that the anchor(s) always remain in tension
during its/their service life, thus reducing the cyclic loading on the anchor and
reducing the need for costly onsite investigation or the consequences of failures
during the service life.
[0022] Features of the system, apparatus and method for installing a subsea foundation in
accordance with the present invention are set out in the appended Claims.
[0023] Throughout this specification, reference is made to the preferred embodiment involving
use of grout as a solidifying anchoring material to secure the anchor in the seabed
and the preferred embodiment was grout, pre-installed in grout bags. However, it is
to be understood that any material which changes from a fluid form to a solid form
so as to provide an anchoring material can be used for this function. References to
"grout" are to be interpreted and understood accordingly.
[0024] Furthermore, although the preferred means of pre-installing the solidifying anchoring
material which solidifies around the anchor bar is in grout bags, the invention is
not limited to this means of pre-installation of the solidifying material.
[0025] The present invention will now be described more particularly, by way of example
only, with reference to the accompanying drawings, in which are shown a number of
alternative embodiments of the system of the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] In the drawings:
Figure 1 illustrates the lowering of the installation and drilling frame and system
for installation of a foundation frame from under a barge 38 to the seabed;
Figure 2 illustrates the installation and drilling frame and system for installation
of foundations on the seabed and the recovery of the lifting frame while the system
for installation of foundations remains connected by umbilical cables 50 to a command
and control vessel 37;
Figure 3 illustrates the foundation frame, installation and drilling frame and the
lifting frame on the deck of a deployment vessel; this is not the preferred deployment
method but is shown as an alternative methodology to the preferred embodiment shown
in the other figures and discussed herein below;
Figure 4 illustrates the lowering of the foundation frame, installation and drilling
frame and lifting frame to the seabed;
Figure 5 is a sectional view of the system of the invention for installing a single
tension anchor foundation into the seabed and showing the foundation frame; and installation
and drilling frame being levelled on the seabed;
Figures 6, 7 and 8 are a sectional view of the system of the invention for installing
a single tension anchor foundation and illustrate the drilling of the tension anchor
into the seabed and illustrating the grouting and the application of pre loading/proof
loading to the tension anchor to check the integrity of the installation of the foundation
frame and increase the penetration of the tension anchor into the seabed;
Figure 9 is an enlarged view showing the conductor shoe and grout bags;
Figure 10 is an enlarged view of the anchor head;
Figures 11, 12 and 13 are sectional views showing the system of the invention for
installing the single tension anchor foundation configured to incorporate a down the
hole hammer and detachable drill head for installation of a hollow tubular anchor;
Figure 14 shows a sectional view of the drill carriage on which the drill drifter
or rotary drive head will be mounted, and the ram and pulley arrangements that will
be used to move the drill carriage up and down the drill mast;
Figures 15, 16, 17, 18, 19 and 20 show the sequence of operations for installation
of a foundation frame provided with three tension anchors, on the sea bed using an
under-slinging barge incorporating lifting equipment;
Figures 21, 22, 23, 24, 25, 26, 27 and 28 show the sequence of operations for installing
an electrical connection plate, J-tube and a length of sub-sea export cable on to
the foundation frame using an alignment and installation frame and cable installation
vessel;
Figures 29, 30, 31, 32, 33, 34, 35, and 36 show the installation of a nacelle using
an alignment and installation frame;
Figures 37, 38, 39, 40, 41, 42, 43, 44 and 45 show the installation of a nacelle and
J-tube subsea cabling carried out in a single operation;
Figure 46 is a perspective view of one embodiment of the invention for the installation
of a three anchor foundation, showing the foundation frame and including the installation
and drilling frame land ifting frame with alignment members;
Figures 47, and 48 are sectional views of the means provided for adjusting the length
of the foundation legs showing so that the foundation frame can be levelled and also
so that the foundation legs can be installed and tested and pre-loaded independently
while ensuring that jacking loads are not transferred into the foundation frame.
Figures 49, 50, 51 and 52 show the sequence of operations for using the levelling
legs of the installation and drilling frame to level the foundation frame during drilling
and ensuring that the foundation frame remains level after anchor installation in
the sea bed.
DETAILED DESCRIPTION OF THE DRAWINGS
[0027] In the drawings, the following reference numerals are used to indicate the correspondingly
indicated features:
- 1. Levelling Jack Base Plate
- 2. Levelling Jack and Accumulator
- 3. Anchor Stop block
- 4. Chuck
- 5. Rotary Drifter Head
- 6. Manifold/Valve Block
- 7. Hydraulic flow/return and bleed lines
- 8. Grout Lines
- 9. Grout Flushing Line
- 10. Side Entry Swivel
- 11. Drill Rig Support Housing
- 12. Water Pump
- 13. Drill String/Hollow Anchor
- 14. Mechanical Clamp/Connection
- 15. Alignment Guide
- 16. Foundation frame
- 17. Grout/Manifold/Valve Block
- 18. Decommissioning duct for explosive charge
- 19. Bearing Plate
- 20. Grout Bags
- 21. Conductor Shoe
- 22. Drill String/Anchor Head
- 23. Conductor
- 24. Penetrating Shoe
- 25. Seal
- 26. Arisings Exhaust Duct
- 27. Bleed valve
- 28. Jacking Chamber
- 29. Stressing Stool
- 30. Subsea Structure/Apparatus
- 31. Shear Key
- 32. End Stop
- 33. Aligning guide
- 34. Adjustable Levelling Leg
- 35. Foundation leg shear key
- 36. Grouted Connection
- 37. Command and Control Vessel
- 38. Deployment Barge
- 39. Tug Boat
- 40. Installation and Drilling Frame
- 41. Foundation Frame
- 42. Lifting Frame
- 43. Nacelle/Cable Deployment and/or retrieval frame
- 44. Bend Restrictors
- 45. Sub Sea Export Cable
- 46. Nacelle
- 47. Cable Drum
- 48. Cable Engine
- 49. Shute
- 50. Umbilical
- 51. Cable Installation Vessel
- 52. Top Drive Rotary Head
- 53. Down the Hole Hammer
- 54. Detachable Drill Head
- 55. Tubular anchor/casing
- 56. Casing Drive Shoe
- 57. Drill Carriage
- 58. Drill Carriage wire rope
- 59. Drill Carriage Sheave
- 60. Drill Carriage Ram
- 61. Electrical Connection Plate (wet mate)
- 62. J Tube with articulated joint
- 63. Mechanical Coupling Means
- 64. Alignment Guide members
[0028] Referring initially to Figures 1 and 2, in this preferred embodiment, the foundation
frame, the installation and drilling frame and lifting frame are pre assembled and
brought to site preferably winched underneath the deployment vessel 38, a floating
platform or barge. An additional command and control vessel 37 will remain connected
to the installation and drilling frame by various cables, hoses and load wires to
provide power to operate the drills, hydraulic systems etc. to supply and deliver
the grouts for the operations and to send command and receive feedback signals for
the operation of the installation and drilling frame.
[0029] An alternative but less preferred option, as shown in Figures 3 and 4, the foundation
frame, installation and drilling frame and lifting frame are assembled on the deck
of a deployment vessel 38, which may be a heavy lift barge or a DP vessel with sufficient
deck and crane capacity to lift and lower the foundation frame, the installation and
drilling frame and the lifting frame from the vessel deck to the seabed. In the case
of the DP vessel, the foundation frame could be firstly lowered onto the seabed, then
installation and drilling frame could be lowered and mechanically connected to the
foundation frame so that the capacity of its deck crane could be reduced. The DP vessel
could also be connected to the installation and drilling frame and provide the functions
of the second command, control and power supply vessel.
[0030] As shown in Figures 5 and 46, the assembled installation and drilling frame and foundation
frame have now been lowered onto the seabed preferably by a three point lifting arrangement.
The installation and drilling frame is designed so that the three landing/levelling
jacks contact the seabed before the central drill string 13. The installation and
drilling frame incorporates levelling means (see Figures 47 to 52; such that the installation
and drilling frame can be adjusted to level by remotely operating the hydraulic jacks
built into the installation and drilling frame. The command signals are sent from
the command vessel. Sensors on the drill frame will indicate when the foundation frame
is within tolerance. Any number of drill strings can be installed per foundation frame.
The drill string(s) and foundation frame can be installed at the same time, as for
example, the arrangement shown in Figure 11 which shows a foundation frame with three
drill strings. Shock absorption can be incorporated into the landing/levelling legs
by installing hydraulic accumulators and valves into the hydraulic circuit thereby
reducing shock loads and the requirement for heave compensation on the lowering equipment.
[0031] Using data supplied to the command vessel from sensors installed on the installation
and drilling frame and the foundation frame, the position, level and alignment of
the foundation frame can be verified.
[0032] If the position of the installation and drilling frame/foundation frame is within
tolerance i.e. there is sufficient travel in the jack legs 2 to bring the foundation
frame into level, the lifting frame is disconnected from the installation and drilling
frame/foundation frame and the lifting frame is recovered to the deployment vessel.
[0033] In any case the deployment of the installation and jacking frame and foundation frame
to the sea bed, the disconnection of the lifting frame and it recovery to the installation
vessel must be carried out during one single tidal cycle i.e. during either a flood
or ebb cycle. If for any reason the deployment to the sea bed cannot be completed
in the time allotted the operation will be aborted and if required remobilised for
the next tidal window.
[0034] An alternative but less preferred option would be to use two tugs one upstream and
one downstream, to position the deployment barge, this option would make the marine
operations more complicated but would extend the window for deployment of the equipment
onto the seabed to more than one tidal cycle.
[0035] In any iteration where more than a single foundation frame/drill string is being
installed, a system is incorporated into the foundation frame legs so that the length
of each leg can be adjusted so as to compensate for unevenness or sloping gradient
in the seabed as shown in Figures 47 to 52.
[0036] The deployment vessel can now depart the deployment site and return to port or stand
by until it is required later in the operations.
[0037] The installation and drilling frame and consequently the foundation frame to which
it is connected can now be levelled and if required, lowered until the foundation
leg bearing plate 19 touches the seabed by adjusting the hydraulic pressures in the
three rams built into the installation and drilling frame. Hydraulic oil pressure/flow
can be supplied from either, hydraulic power packs and valves built into the installation
and drilling frame or through umbilical/cables from hydraulic power packs on the command
and control vessel to the installation and drilling frame. The alignment and level
of the foundation frame can also be determined from signals sent from sensors on the
installation and drilling frame to instruments on the command vessel to confirm that
it is within the required specification.
[0038] Referring now to Figures 5 to 10 a drill string comprising a hydraulic rotary drifter
head 5, chuck, side entry swivel 10 for introducing flushing fluid and grout to the
anchor, stop block 3 on the anchor to transfer the jacking loads from the anchor bar
13 to the stressing stool 29, a hollow centre anchor bar 13, a drill bit 22, hydraulic
clamps to grip the anchor and a system to raise and lower the drill string is pre-installed
on the installation and drilling frame as shown in Figure 14. The hydraulic or pneumatic
lines 7, grout lines 8 and flushing line 9 required to operate the drill system can
be marshalled inside the outer casing using retractable cables as shown in Figure
6. Using the rotary percussive drifter head 5, the drill bit 22 forms a hole in the
seabed and concurrently drives the conductor shoe 21 into the seabed until the conductor
shoe reaches its end stop 32. Shear keys 31 in the conductor shoe 21 then break off
or deform allowing the drill bit and anchor to continue forming the anchor hole. As
the anchor is drilled into the seabed, the drill arisings are flushed out of the drilled
hole along the drill conductor and exit through the exhaust duct 26 into the water
column. The flushing medium, preferably sea water, is supplied from a water pump 12
mounted on the installation and drilling frame but alternatively water, weak grout
mix, drilling mud or air from the command and control vessel could also be supplied
for the same function. Drilling continues until the stop block 3 on the anchor bar
contacts the stressing stool top plate 29.
[0039] Preferably, a cementatious grout is introduced into the central channel in the anchor
bar from the command vessel through a grout line.
[0040] Furthermore, although the preferred means of pre-installing the solidifying anchoring
material which solidifies around the anchor bar is in grout bags, the invention is
not limited to this means of pre-installation of the solidifying material.
[0041] Alternatively, instead of using cementations grout, a chemical anchoring material
which solidifies may be used. Thus, for instance, in the embodiment using a chemical
anchoring material, the chemical anchor dosing, mixing, installation equipment with
the associated power packs, pipe work and valves is installed on the installation
and drilling frame instead of grout pre-installed in grout bags.
[0042] Throughout this specification, reference is made to the preferred embodiment involving
use of grout pre-installed in grout bags. However, it is to be understood that any
material which changes from a fluid form to a solid form so as to provide an anchoring
material can be used.
[0043] The quantity and supply pressure of the grout injected during installation can be
monitored and the values used to determine that the anchor bar has been fully grouted.
De-bonding material can be pre-installed over a set length of the upper section of
the anchor bar so that when the anchor bar is pre-loaded, the de-bonded length is
free to stretch.
[0044] Alternatively in locations where there is significant overburden or where the characteristics
of the sea bed or foundation design, preclude the use of a self-drilling anchor, down
the hole drilling techniques can be used to install a hollow tubular anchor.
[0045] Referring now to Figures 11, 12 and 13, the drill string now comprises a top drive
rotary head (52), a chuck (4), a side entry swivel (10) a drill string (13) a "down
the hole" hammer (DTH) (53), a tubular casing/anchor (55) incorporating a casing drive
shoe (56) and a consumable detachable drill bit (54).
[0046] As before, the drill is started and the drill hole progressed. Rotary motion and
vertical pressure is applied through the rotary motion head from the drill carriage.
The flushing medium is supplied through the side swivel and hollow drill string to
the drill bit. Arises are flushed out of the drilled hole and through exhaust duct
26.
[0047] As before, drilling proceeds until end stop 3 contacts the top of the stressing stool
29. Grouting can now take place around the annulus of the anchor as before. On completion
of this grouting process, the drill bit is disconnected and the drill string and DTH
retracted. Further grout can be placed as the DTH is retracted, to fill the centre
of the drill string if required. At this stage the grout lines and DTH can be flushed
out. A non-return/check valve is incorporated into the drill bit to maintain the head
of grout around the anchor bar. On completion of this grouting operation, the DTH
can be retracted and locked in the fully raised position.
[0048] Now referring to Figure 9, following curing, a fluid preferably water is introduced
through grout manifold/valve block 17 into jacking chamber 28. Valve 27 is opened
to bleed off any trapped air. When all air has been expelled, valve 27 is closed and
the pressure in jacking chamber 28 is increased to a predetermined value. This will
have the effect of moving the stressing stool to react against stop block 3 on the
anchor bar and so transfer the load through the anchor bar into the point of fixity
within the seabed. This will have the further effect of forcing the foundation frame
penetrating shoe 24 further into the seabed. The force applied can be controlled by
adjusting the fluid pressure in chamber 28. This pressure can be further adjusted
to set values and timings to load and unload the anchor as required proving the installation.
[0049] The bearing plates 19 determine the maximum amount of penetration of the foundation
frame into the seabed. When testing of the anchor is complete, marker dye followed
by a grout will be introduced into the jacking chamber 28. Valve 27 is partially opened
so that a pre-determined pressure remains in the circuit. When the marker dye flows
out of valve 27, the valve is fully closed and the grout pressure increased so that
a force equal to the projected maximum design load, with an additional appropriate
allowance factor, of safety is now applied to the anchor. Inlet valve 17 is closed
and the pressure monitored.
[0050] Now grout bags 20 preinstalled in the bottom of the foundation frame can be inflated
by pumping grout through grout manifold 17 and so fill any voids between the bottom
of the foundation frame and the seabed. This grout when cured will further resist
any penetration of the foundation frame leg into the seabed, provide scour (erosion)
protection at the base of the foundation frame and resist the shear loads imposed
on the structure.
[0051] In any iteration where more than a single foundation frame/drill string is to be
installed, adjustment of the foundation legs is provided. The procedure is described
as follows.
[0052] Referring to Figures 47, and 48 the inner foundation leg 34 is held in the raised
position by drill string 13, this is in turn held by the drill chuck and carriage.
The foundation frame is placed on the seabed and the foundation levelled as before.
Referring to figure 49 and 50 it can be seen that these inner foundation legs are
held clear of the sea bed after the levelling of the installation and drilling frame.
[0053] The drill carriages are operated and the inner foundation frame leg is free to move
through the foundation frame 41, guides 33 keep the inner leg central with the foundation
frame.
[0054] Following drilling, grouting, testing and pre tensioning of the anchors grouting
of the annulus of the inner foundation leg and foundation frame will take place. Inlet
valve 17 and bleed valve are opened. Marker dye followed by grout is introduced through
inlet valve 17 into the chamber formed between the inner foundation leg and the foundation
frame. When dye and grout are observed by cameras and / or sensors mounted on the
frame, exiting from bleed valve 27 both inlet and bleed valves are closed. The grout
is allowed to cure. Seals 25 exclude water from this chamber and hold the grout under
pressure. Shear keys 31 and 35 or other features are installed to resist the design
loads through the grouted connection.
[0055] Alternately a mechanical connection could be used (not shown)
[0056] The deployment vessel now returns to the deployment site and the lifting frame is
lowered over the installation and drilling frame. Transponders on the installation
and drilling frame, lifting frame and foundation frame can be used to assist in positioning
the individual assemblies.
[0057] The lifting frame incorporates members so that the lifting frame will self align
with the installation and drilling frame during lowering and assembly. Furthermore,
these alignment members can be arranged so that when the lifting frame and the installation
and drilling frame are connected, the alignment members on the lifting frame assist
with the alignment and connection of the installation and drilling frame to the foundation
frame, for instance in the case where the foundation frame is placed first on the
seabed and the installation and drilling frame later, or during decommissioning. The
lifting frame is then mechanically connected to the installation and drilling frame.
Once the lifting frame has been connected, the mechanical coupling means between the
installation and drilling frame and the foundation frame are released and the lifting
frame and installation and drilling frame recovered to the deployment vessel. The
command vessel can marshal the supply lines during these operations. When the installation
and drilling frame and lifting frame have been recovered the vessels can depart the
site.
[0058] When the installation and drilling frame is disconnected from the foundation frame
the installation and drilling frame and the lifting frame can, if required, be used
to install the permanent equipment on the foundation frame.
[0059] If for example the foundation frame is to be used to support a grid connected tidal
stream turbine, the method used would be as follows: Referring to Figures 21 to 28
inclusive, the installation of an electrical connection plate, J-tube and cable will
be described.
[0060] If the lifting frame is not suitable or cannot be easily modified/adjusted for the
proposed operations, the mechanical couplers installed on the lifting frame can be
removed and installed in a purpose designed and fabricate installation and alignment
frame as follows:
The deployment barge will be towed to a suitable load out location. The installation
frame will be lowered to the sea-bed. Mechanical couplers will be operated disconnecting
the installation and drilling frame 40 from the lifting frame 42. The lifting frame
will now be recovered to the barge.
[0061] The mechanical couplers will be removed from the lifting frame 42 and reinstalled
into a purpose designed and fabricated alignment and installation frame Figure 43.
This installation frame will be winched up under the barge as before.
[0062] An electrical connection plate 61, J-tube with articulated joint 62, a length of
export cable with a dry mate connector and bend restricting cable protectors pre-installed
on the shore end will be lifted into the alignment/installation frame see Figure 21.
This assembly will be held in place on the alignment and installation frame by its
self-weight and features on the frame and assembly will prevent lateral movement during
deployment. Sea fastenings/or stop blocks will be provided for transport to the deployment
location.
[0063] The dry-mate connector and cable end will be transferred on to the deck of a suitable
vessel equipped with cabling equipment. This dry-mate connector and cable will be
routed through a cable engine 48 and spooled on to a powered drum 47 on the vessel
as shown in Figure 21. The J-tube is held in a horizontal orientation to reduce the
requirement for a deep water load out berth and a deep water passage to the deployment
site, as would be necessary if it was to be transported in the lowered vertical orientation.
[0064] This deployment spread comprising a tug 39, deployment barge 38, installation frame
with connectors and cable pre-installed, will be towed to the deployment location.
The cabling vessel can travel at a suitable relative position and distance to the
barge 38 necessary to maintain a suitable catenary in the cable and so ensure that
the ratings of the cable are not exceeded.
[0065] Referring to Figure 22, if the tidal and sea and weather conditions at the deployment
location are suitable for the operation and once close to the designated foundation
or at a sheltered location with sufficient water depth for the remaining portion of
the passage, the j-tube will be lowered into the vertical position by a winch on the
barge, as shown in Figure 22.
[0066] Alternatively, the J tube could be partially lowered and the cabling vessel could
control the final lowering of the cable and J tube. The cabling vessel can pay out
cable or move position to keep the required tension catenary in the export cable,
the cable engine will ensure the required tension is maintained.
[0067] The tug will now be positioned close to the foundation and hold station see Figures
21 to 28. The connection plate j-tube and alignment and installation frame will be
lowered to a depth such that the alignment guides can contact the central tower. The
tug will pay out/recover its tow rope and move the barge so that the installation/alignment
frame moves towards the foundation tower. The alignment guides can, if required, use
the central tower as a guide to centralise the connection plate over the foundation
tower.
[0068] Sensors, transducers, cameras, sonar etc. can, if required, be installed on the installation
frame this data can be used to confirm the position of the j-tube and connection plate
relative to the foundation.
[0069] When the connection plate and j-tube are in the correct position, so that the alignment
features on the installation frame contacts the foundation tower, it will be further
lowered and so mate the connection plate and j-tube with the foundation.
[0070] On confirmation that the connection plate and j-tube are correctly aligned and seated
the installation frame is further lowered and so disconnects from the connection plate
and j-tube. The tug can now adjust the tow line to move the barge and so move the
installation frame away from the foundation. Once clear of the foundation the installation
frame can be recovered and sea fastened to the barge.
[0071] The tug and installation vessel can now depart the site. The cabling vessel can be
specified so that it can remain on site throughout the full tidal cycle. If unfavourable
weather conditions are forecast the cabling vessel can lay the remaining cable and
end connector on to the seabed for recovery later and connection to the export cable.
[0072] Alternately, a pre-laid export cable end could be recovered to the vessel deck. The
electrical and mechanical connections can be formed and the cable re-laid on the seabed.
[0073] Furthermore, referring now to 29 to 45, following the same procedures as described
above, a nacelle can be installed on the foundation frame anchored into the seabed.
Referring initially to Figure 29, a nacelle installation and alignment frame are installed
on the deployment barge as shown in Figure 29.
[0074] A nacelle will be lifted from the load out area and placed in the nacelle installation
alignment frame.
[0075] Alternatively a nacelle or a number of nacelles can be loaded onto a flat top barge,
placed in transport frames and transported to an intermediate laydown area at a sheltered
location. This laydown area will have sufficient water depth to give overhead clearance
for the installation barge. Once at the location the nacelles, and transport frames
can be lifted onto the seabed at agreed locations.
[0076] The installation barge will now be towed to this intermediate laydown area and hold
position over a nacelle. The nacelle installation frame will be lowered from the installation
barge and pick up the nacelle from the transportation frame.
[0077] The nacelle and installation frame will then be winched up under the barge and sea-fastened.
The barge will be towed to its foundation location and hold station close to the tower.
Sea-fastenings will now be removed.
[0078] As with the cable connection plate and J tube, this nacelle installation frame will
be lowered to a depth so that the alignment guides on the installation frame may contact
the central tower to act as an installation guide, but not so low that the turbine
blades can contact the tower - see Figure 30.
[0079] The tug will let out or recover the tow line, and so move the barge so that alignment
guides on the installation frame may contact the central tower to guide and centralises
the nacelle over the central tower.
[0080] The nacelle/installation frame will be now lowered so that the nacelle aligns and
seats on the wet-mate connector plate on the on the central tower.
[0081] The installation frame is now further lowered to disengage from the nacelle.
[0082] The tug will recover/let out its tow line to move the barge and so the recovery frame
away from the installed nacelle. Once clear of the nacelle installed on the foundation
frame the installation frame can be recovered to the barge.
[0083] In another embodiment with reference to figures 37 to 44 a nacelle J tube and export
cable could be installed in a single operation. This would have the advantage of removing
the need to provide, install and maintain a wet mate electrical connection, but would
have the disadvantage of requiring significant cabling works to disconnect and handle
the export cable before a nacelle is removed or exchanged.
[0084] These or similar procedures can be used to swap out nacelles or cabling during planned
maintains of the turbine or to effect repairs caused by breakdowns or mechanical damage.
[0085] For removal of the nacelle or other equipment, the alignment and installation frame
will be positioned close to the foundation frame, at a depth so that the frame can
contact the central tower of the foundation frame but pass under the apparatus to
be removed. When the alignment and installation frame contacts the central tower the
deployment vessel will maintain position. The installation and recovery frame can
now be raised and features on the frame and apparatus will guide the installation
frame and engage with the apparatus. Sensors on the alignment and installation frame
will verify that the correct engagement has taken place. The installation frame can
be further raised so removing it from the tower. It can now be raised and sea-fastened
to the deployment vessel.
[0086] At the end of the service life of the foundation frame, all the equipment is removed
using the same methods as described above, to leave the foundation frame as it was
installed. The installation equipment is mobilised and the lifting frame and installation
and drilling frame are once more lowered over the foundation frame. The lifting frame
and installation and drilling frame are mechanically connected to the foundation frame
using mechanical couplings 14. A shaped explosive charge is installed by ROV into
the decommissioning duct 18 and the duct sealed. If required hydraulic pressure is
applied to the jack legs 2 to apply an upward force on the foundation frame. The explosive
charge is detonated remotely and the anchor bars severed. The foundation frame, installation
and drilling frame and lifting frame are then recovered to the decommissioning vessel.
[0087] Thus, features of the system of the present invention are as follows:
- 1. Hollow "self drilling" anchor; by "self drilling" is meant that the anchor is provided
with drilling means which operate to put the anchor under tension.
- 2. Suitable for a variety of sites and foundations.
- 3. Remotely operated so capable of operating in any water depth.
- 4. No fixed anchor length.
- 5. Levelling foot detail cylinder that can roll.
- 6. Can be configured as single drill string, tripod, or multiple drill strings.
- 7. Adjustable jack legs.
- 8. Accumulators to reduce shock loading.
- 9. Accumulators in hydraulic supply lines to absorb back pressure in umbilicals,
- 10. ALL anchors are tested and preloaded so that the anchor loads during their service
life are higher than the maximum design working load so eliminated cyclic loading
and reducing fatigue.
- 11. Grout bags to fill gap between foot and seabed to transfer loads and prevent further
penetration into seabed.
- 12. Grout bags to prevent scour.
- 13. Gussets plates to limit the penetration of the foot into the seabed.
- 14. Self alignment members.
- 15. Duct for explosive charge during decommissioning.
- 16. In an alternative embodiment, a chemical anchor instead of grout can be pre-installed
on the installation and drilling frame.
[0088] The advantages of the system and method of the invention are as follows:
- 1. Tension anchors.
- 2. Installation and drilling frame designed so that it will act as a gravity structure
and keep the foundation frame on the sea bed even before any drilling takes place.
- 3. The installation of self-drilling tension foundations.
- 4. The application of proof loading and pre loading of the tension anchor to prove
the suitability of the anchor and reduced the cyclic loading and so fatigue.
- 5. The ability to apply a load to the anchorage over and above that which it will
experience during its service life.
- 6. The ability to force the foundation frame into rock to provide resistance to shear
loads.
- 7. Smaller diameter anchor holes are achieved thereby resulting in less spoil deposited
in the sea-bed / water column. Since mostly small diameter anchor holes are required,
this brings about the subsequent reduction in arisings from the drilling operation.
The ability to easily change the length and diameter of the anchor rod to suit a wide
variety of seabed and foundations.
- 8. The ability to install tubular hollow section anchors using DHH technology.
- 9. Use the environmental conditions, tidal velocity and direction etc., to assist
with the alignment of the various subassemblies during the operations.
[0089] The system and method of the present invention are particularly advantageous where
the bed comprises a rocky or hard material and levelling of the installation and drilling
frame is particularly problematic combined with technical difficulties of providing
a foundation frame.
- 1. In this embodiment, the foundation frame comprises a three legged foundation frame
provided with a central support column.
- 2. The sequences of operations for deploying the foundation frame are as follows:
- 3. The foundation frame, installation and drilling frame with drill strings preinstalled
is commissioned and lifted onto the seabed at a suitable sheltered location.
- 4. The deliver vessel is positioned over the foundation frame and the installation
and drilling frame and a lifting frame is lowered over the installation and drilling
frame and the foundation frame.
- 5. The lifting frame will "self-align" with the installation and drilling frame. By
the term, "self-align" is meant that the lifting frame is provided with alignment
guide members 64 (as shown in for instance Figure 46) that will, under the weight
of the frame, contact the foundation frame, and rotate and guide the mechanical couplers
63 towards the lifting points on the installation and drilling frame. Additional funnels/guides
on top of the lifting tubes will assist with the final alignment and guiding of the
lifting couplers into place. Now, with the lifting frame aligned with the installation
and drilling frame. The lifting devices are operated so that the installation and
drilling frame and the foundation frame are connected to the barge.
- 6. The three winches on the barge will be operated and the installation and drilling
frame and the foundation frame are raised underneath the barge and sea-fastened.
- 7. The umbilical lines, hydraulic lines and grout lines are transferred from the quayside
and transferred to the command vessel.
- 8. The installation spread will comprise a tug boat for pulling a barge capable of
heavy lifting; the heavy lift barge with the foundation frame, installation and drilling
frame and the lifting frame under-slung and sea-fastened and the command vessel with
the required generators hydraulic power packs and grout batching and pumping equipment.
- 9. The installation spread will be towed to the deployment location. The sea-fastenings
will be disconnected and the foundation frame and the installation and drilling frame
lowered to the seabed using the lifting frame and the three winches on the barge.
- 10. On confirmation that the location, heading, water depth etc. are within tolerances
from data received from sensors attached on the installation and drilling frame, the
mechanical couplings between the lifting frame and the installation and drilling frame
will be disconnected. The lifting frame will then be recovered to the underside of
the barge.
- 11. The tug will then tow the barge away from the deployment site and stand by.
- 12. Using power packs and command and control systems on the command vessel, the installation
and drilling frame will be levelled. Following confirmation from sensors on the installation
and drilling frame, that the installation and drilling frame and the foundation frame
are within tolerance, the plurality of drill head 34 (see Figure 46), in which three
drill heads 34 are shown) will be operated. These drilling operations can be carried
out concurrently or singly dependant on the required time frame and the number and
ratings of the power packs on the command vessel and umbilicals connecting the vessel
to the installation and drilling frame.
- 13. The fluid required for flushing the drill arises from the hole, can comprise air
or water supplied from the command vessel or water supplied from an under-water pump
on the installation and drilling frame. Drilling progress, flushing fluid pressure,
removal of arises and debris can be monitored and adjusted from instrumentation on
the installation and drilling frame receiving information supplied by sensors on the
installation and drilling frame.
- 14. The drilling arises will be expelled through arise exhaust duct 26 to the sea
bed. If required, this exhaust duct can be extended back up to the command vessel
where these arises could be collected for disposal. The function of conductor shoe
21 is to form a path for the arises at the interface between the sea-bed and the rock
and stop arises filling the space between the penetrating shoe 24 and the bottom of
the jacking chamber bearing plate 19. The function of seal 25 is to prevent drilling
arises entering the area above the jacking chamber and possibly preventing good contact
between the anchor head stop block 3 and the stressing stool 29.
- 15. When the anchor head stop block 3 on the drill string makes contacts the top of
the stressing stool 29 on the foundation frame 33, the drilling operation for that
anchor will be complete.
- 16. A predetermined quantity of grout will be introduced from the command vessel,
through valve block 17, grout line 8, side entry swivel 10, the open centre of the
drill string, the drill string anchor head and into the space between the drilled
hole and the drill string. Alternately, epoxy compound could be mixed and placed from
batching equipment mounted on the installation and drilling frame, so reducing the
length of the delivery lines and quantity of chemical anchor required.
- 17. This process is repeated for the remaining drill strings.
- 18. Following sufficient curing of the grout, determined by water temperature rock
temperature grout strength determined by crush tests and required test loads required,
water is introduced into jacking chamber 28 through valve block 17. Bleed valve 27
is then closed and the water pressure increased until the load exerted between the
stressing stool 29 and the anchor stop block 3 has reached the proof load required
for the application. The proof load is the load that the anchor can accept without
damage to the anchor, solidifying material (for example, grout), bond or rock or anything
else in the load path. If an anchor is correctly installed, applying the proof load,
be it 1.5 or 2 times the design working load will not damage the anchor. The water
pressure can be adjusted so that a test cycle for the anchor can be carried out to
the specification. If bleed valve 27 and valve block 17 are both closed, pressure
sensors on the jacking chamber will show that the required loads on the anchors can
be maintained.
- 19. A further effect of stressing the anchors will be to force the penetrating shoe
into the seabed.
- 20. When all anchors have been proof tested, bleed valves 27 will be opened and the
load on the anchors reduced to the designed working load plus a predetermined amount
to ensure the anchor does not become un-stressed during its service life, which could
result in fatigue stresses in the anchors.
- 21. Grout will be introduced into grout bags 20 to fill any gap between the bearing
plate 19 and the seabed.
- 22. Valve block 17 and bleed valve 27 will be opened and grout will be introduced
into jacking chamber 28 forcing the water out of the chamber. A marker dye may be
introduced before the grout to aid confirmation that the complete removal of the water
in the chamber. When dye/grout are confirmed exiting from bleed valve 27 this valve
will be closed and the grout pressure increased so that the load in the anchor reaches
the required figure. Valve block 17 will be closed and the load in the anchor monitored.
- 23. These operations will be repeated for the remaining anchor bars.
- 24. Grout will be introduced into the gap between the telescoping section of the leg
and the foundation frame or a ratchet/threaded section will be operated by a ram on
the installation and drilling frame. More detail and a drawing of this section need
to be done.
- 25. Referring to Figure 46, when all anchor bars have been tested and preloaded the
barge and lifting frame is remobilised to the deployment site, the lifting frame 42
will be lowered over the installation and drilling frames so that mechanical coupling
means 63 engage with their lifting points. The mechanical coupling means 63 are then
engaged and the mechanical coupling means 14 opened. The installation and drilling
frame is winched under the barge leaving the foundation frame connected to the seabed.
The barge will be towed to the load-out location and the next foundation frame/anchors
etc. fitted alternatively, the installation and drilling frame is lowered to the sea-bed
at a suitable location. Mechanical coupling means 63 is operated thereby disconnecting
the installation drilling frame 40 from the lifting frame 42 foundation frame. The
lifting frame will be recovered to the underside of the barge.
- 26. The mechanical coupling means 63 will be disconnected from lifting frame 42 and
installed into nacelle/electrical connection plate alignment/installation frame. The
nacelle installation and drilling frame is winched up under the barge as shown in
Figure 21.
- 27. A wet-mate connection plate, j-tube with articulated joint, and a length of export
cable with a dry mate connector installed on the shore end will be lifted in to the
alignment/installation frame as shown in Figure 21.
- 28. The dry-mate connector and cable end will be passed on to a vessel equipped with
cabling equipment. This dry-mate connector and cable will be spooled on to a powered
drum on the cabling vessel as shown in Figure 21.
- 29. The deployment spread comprising a tug, deployment barge, installation frame connectors
and cable and cabling vessel will be towed to the deployment location. Once close
to the designated foundation frame or in a sheltered local location with sufficient
water depth on route, between this location and the foundation frame, the j-tube will
be lowered to vertical position see Figure 22. The cabling vessel can pay out cable
or move position to keep the export cable in the correct tension. The tug will be
positioned up tide from the foundation frame and hold station. The connection plate
j-tube and alignment and installation frame will be lowered to a depth that the alignment
guides can contact the central tower. The tug will pay out its tow rope and move the
installation frame towards the foundation frame. The alignment guides can use the
central tower to guide and centralise the connection plate over the foundation frame
tower. Sensors, cameras and sonar on the installation frame will confirm the position
of the j-tube and connection plate relative to the foundation frame.
- 30. When the connection plate and j-tube are in the correct position the installation
frame will be lowered installing the connection plate and j-tube on the foundation
frame. The cabling vessel can move position or pay out cable to keep the export cable
in the correct tension.
- 31. On confirmation that the connection plate and j-tube are correctly seated the
installation frame is further lowered and disconnected from the connection plate and
j-tube. The tug can recover tow line to disengage the installation from the foundation
frame. Once clear of the foundation frame the installation frame can be recovered
and sea fastened to the barge.
- 32. The installation barge can be towed to the load out area to collect the next electrical
connection and cabling assembly or demobilised.
- 33. The cabling vessel can now lay the remaining cable on to the seabed or recover
a pre-laid export cable with connector to the vessel deck. The electrical and mechanical
coupling means can be formed and the cable laid on the seabed.
- 34. A nacelle installation and alignment frame will be installed on the deployment
barge as shown in Figure 29.
- 35. A nacelle will be lifted from the load out quay and placed in the nacelle installation
alignment frame.
- 36. Alternatively a nacelle or any number of nacelles will be loaded onto a flat top
barge, placed in transport frames and transported to an intermediate laydown area
at a sheltered location. This laydown area will have sufficient water depth to give
overhead clearance for the installation barge. Once at the location, the nacelles
and transport frames will be lifted on top the seabed at agreed locations.
- 37. The installation barge will be towed to the intermediate laydown area and manoeuvre
over a nacelle and hold station over the nacelle. The nacelle installation frame will
be lowered from the installation barge and pick up the nacelle.
- 38. The nacelle and installation frame will be winched up under the barge and sea-fastened.
- 39. The barge will be towed to its foundation frame location and hold station close
to the tower and sea-fastenings removed.
- 40. The installation and drilling frame will be lowered so that the alignment guides
on the installation and drilling frame are low enough to contact the central tower
to act as an installation guide, but not low enough for the turbine blades to contact
the tower as shown in Figures 32 and 33.
- 41. The installation tug will let out or recover the tow line, connected to the installation
barge, so that alignment guides contact the central tower to guide and centralises
the nacelle over the central tower.
- 42. The nacelle/installation frame will be further lowered so that the nacelle aligns
and seats on the wet-mate connector plate on the on the central tower.
- 43. The installation frame is then lowered and disengaged from the nacelle.
- 44. The tug will recover/let out its tow line to move the barge and so move the recovery
frame away from the installed nacelle. Once clear of the foundation frame/nacelle,
the installation frame 43 can be recovered to the barge.
1. A system for installing a foundation for a subsea structure wherein the system comprises
a foundation frame (16) which is provided with anchoring means comprising at least
one tension anchor and means for fixing said at least one tension anchor into the
seabed; and the system also comprising means for controlling the operation of the
foundation frame; the foundation frame being adapted to support and be removably connected
with apparatus such as energy conversion apparatus, wherein, in use, the anchoring
means is operated to become embedded in the seabed; wherein the system comprises an
installation and drilling frame carrying drilling means; the installation and drilling
frame providing sufficient weight to enable the system to act as a gravity foundation
while the installation is taking place; the installation and drilling frame being
removably connectable to the foundation frame.
2. A system for installing a subsea foundation on the seabed as claimed in Claim 1; wherein
the system comprises means for pre-loading or proof loading to test the suitability
of the anchor; optionally wherein the foundation frame structure is used as the locating
template for the drilling equipment in order to achieve accurate positioning of the
tension anchors.
3. A system for installing a foundation for a subsea structure as claimed in any preceding
Claim wherein the means for embedding said at least one tension anchor comprises the
foundation frame; and the installation and drilling frame; optionally wherein the
foundation frame structure is used as the locating template for the drilling equipment
in order to achieve accurate positioning of the tension anchors; optionally wherein
a single tension anchor or multiple tension anchors are provided; and optionally wherein
the tension anchor comprises a hollow tubular anchor.
4. A system for installing a foundation for a subsea structure as claimed in Claim 3
wherein the at least one tension anchor foundation is configured to incorporate means
for installation of the hollow tubular anchor, said means for installation of the
anchor in the seabed comprising a "down the hole" hammer (53) and a detachable drill
head.
5. A system for installing a foundation for a subsea structure as claimed in any preceding
claim wherein the at least one tension anchor is provided with means for embedding
said at least one tension anchor in the seabed, said means for embedding the at least
one tension anchor comprising drilling means, optionally wherein the drilling means
comprising means for moving a drill carriage up and down a drill mast; optionally
wherein the means for embedding said at least one tension anchor in the seabed further
comprises the drill carriage on which a drill drifter or rotary drive head is mounted;
optionally wherein the means for moving a drill carriage up and down a drill mast
comprises a ram and pulley arrangement used to move the drill carriage up and down
the drill mast; and optionally wherein the diameter and or length of the anchor bar
and of the bond length into the seabed can be adjusted to suit a wide variety of ground
conditions; and optionally wherein the foundation frame is adapted to carry any number
of drill strings (13, 22).
6. A system for installing foundations for subsea structures as claimed in any preceding
claim wherein the system includes a lifting frame (42) with geometrically interlocking
guides for lowering and raising the assembled frames/foundation frame to the seabed;
optionally wherein the lifting frame for lowering and raising the assembled frames/foundation
frame to the seabed comprises a three point lifting arrangement; optionally wherein
the installation and drilling frame incorporates levelling means such that the installation
and drilling frame will be adjusted to level by command signals given from the command
vessel; optionally wherein includes levelling means comprising a plurality of landing
and levelling legs (34) adapted such that the landing and levelling legs touch the
seabed before the drill string carried on the foundation frame; optionally wherein
shock absorption is incorporated into the landing/levelling legs by incorporating
hydraulic accumulators (2) and valves thereby reducing shock loads on the lowering
equipment.
7. A system for installing foundations for subsea structures as claimed in any one of
the preceding claims wherein means are provided in the foundation frame legs for adjusting
the length of each leg so as to compensate for unevenness or slopes in the seabed;
optionally wherein the means provided in the foundation frame legs for adjusting the
length of each leg so as to compensate for unevenness or slopes in the seabed comprise
a mechanical ratchet.
8. A system for installing foundations for subsea structures as claimed in any one of
Claims 3 to 7 wherein the installation and drilling frame and consequently the foundation
frame to which it is connected can be levelled and if required, lowered until the
foundation frame bearing plate (19) touches the seabed by adjusting the hydraulic
pressure flow in the hydraulic rams built into the installation and drilling frame
legs.
9. A system for installing foundations for subsea structures as claimed in any one of
Claims 3 to 8 wherein hydraulic oil pressure/flow can be supplied from either hydraulic
power packs and valves built into the installation and drilling frame or through hoses
from hydraulic power packs on the command and control vessel (37); optionally wherein
the alignment and level of the foundation frame can also be determined from the command
vessel to confirm that it is within the required specification.
10. A system for installing foundations for subsea structures as claimed in Claim 5 wherein
the drilling means comprise a drill string comprising a hydraulic rotary drifter head
(5), an entry port for introducing flushing fluid and solidifying anchors material
to the anchor, a stop means optionally comprising a stop block on the anchor to transfer
the jacking loads from the anchor bar to a stressing stool (29), a hollow centre anchor
bar, a drill bit, hydraulic clamps to grip the anchor and a system to raise and lower
the drill string is pre-installed on the installation and drilling frame; optionally,
the power lines, grout lines (8) and flushing line (9) required to operate the drill
system are marshalled inside the outer casing using retractable cables;
optionally, using the rotary percussive drifter head, the drill bit forms a hole in
the seabed and concurrently drives the conductor shoe (21) into the seabed until the
conductor shoe reaches its end stop (32);
optionally, shear keys (31) in the conductor shoe then break off or deform allowing
the drill bit and anchor to continue with forming the anchor hole;
optionally, as the anchor is drilled into the seabed, the drill arisings are flushed
out of the drilled hole along the drill conductor (23) and exit through the exhaust
duct (26) into the water column;
optionally, the flushing medium, preferably sea water, is supplied from a water pump
(12) mounted on the installation and drilling frame but alternatively water, weak
grout mix, drilling mud or air from the command and control vessel could also be supplied
for the same function; and
optionally, drilling continues until the stop block on the anchor bar contacts the
stressing stool top plate.
11. A system for installing foundations for subsea structures as claimed in any one of
the preceding claims wherein the anchor bar comprises a central channel through which
a solidifying anchoring material can be introduced for flowing through the control
channel and out of the anchor bar into the area surrounding the anchor bar where the
solidifying anchoring material changes from being in fluid form to being in solid
form so as to embed the anchor bar in the seabed, optionally wherein the solidifying
anchoring material comprises cementatitious grout which is introduced into the central
channel in the anchor bar through a grout line; optionally wherein chemical anchor
dosing, mixing, installation equipment with the associated power packs, pipe work
and valves can be installed on the installation and drilling frame.
12. A system for installing foundations for subsea structures as claimed in any preceding
claim wherein the means for embedding the tension anchor in the seabed further comprises
a stop block on the anchor bar and a moveable stressing stool for transferring the
load through the anchor bar into the anchorage point on the seabed effective to force
the foundation frame penetrating shoe (24) into the seabed and means for controlling
the force applied.
13. A system for installing foundations for subsea structures as claimed in Claim 12 wherein
grout bags (20) are preinstalled in the bottom of the foundation frame at mechanical
clamp/connection and means for inflating the grout bags are provided so that in use,
the pre-installed grout bags can be inflated and so fill any voids remaining between
the bottom of the foundation frame and the seabed whereby this grout, when cured resists
any further penetration of the foundation frame foot into the seabed and provide scour
(erosion) protection at the base of the foundation frame.
14. A method for installing foundations in the seabed, the method comprising the following
step:
providing an apparatus for installing foundations to subsea structures with at least
one tension anchor and providing the apparatus with means for embedding said at least
one tension anchor into the seabed, the apparatus comprising a foundation frame which
is provided with anchoring means, the foundation frame being adapted to support and
be removably connected with equipment such as energy conversion apparatus and the
anchoring means, in use, being embedded in the seabed; and providing the apparatus
with an installation and drilling frame carrying drilling means; the installation
and drilling frame being removably connectable to the foundation frame; the means
for embedding said at least one tension anchor comprises the foundation frame; and
the installation and drilling frame; optionally wherein the method also comprises
the following step:
providing the tension anchor as a hollow tubular anchor, wherein the at least one
tension anchor foundation is configured to incorporate a "down the hole" hammer and
a detachable drill head for installation of the hollow tubular anchor in the seabed.
15. A method for installing foundations in the seabed as claimed in claim 14, the method
comprising the following steps:
connecting the foundation frame to the installation and drilling frame;
(a) installing the drill string(s) onto the foundation frame; and the installation
and drilling frame and lifting the foundation frame; and the installation and drilling
frame with drill string(s) installed, onto the seabed at a suitable sheltered location;
(b) manoeuvring/positioning a delivery vessel over the foundation frame; and the installation
and drilling frame;
(c) lowering a lifting frame over the installation and drilling frame and the foundation
frame;
(d) aligning the lifting frame with the installation and drilling frame;
(e) operating lifting devices so that the installation and drilling frame and the
foundation frame are connected to a barge (38) for deploying the installation and
drilling frame and the foundation frame to the desired site;
(f) operating the winches on the barge so as to position the installation and drilling
frame and the foundation frame underneath the barge and sea-fastening the frames underneath
the barge;
(g) transferring the umbilical lines (50), hydraulic lines and grout lines from the
quayside and transferred to the command vessel;
(h) towing the installation and drilling frame and the foundation frame to the deployment
location; and
(i) At the deployment location, disconnecting the sea-fastenings and lowering the
foundation frame and the installation and drilling frame to the seabed by operating
the lifting frame and winches on the barge; optionally carrying out drilling operation
so as to embed in the seabed, the at least one tension anchor provided on the foundation
frame; and optionally the method comprising the following further step: operating
the tug (39) to tow the barge away from the deployment site and having the tug standing
by at a location remote from the deployment location.
16. A method for installing foundations in the seabed as claimed in any one of Claims
14 or 15, the method comprising the following further steps:
introducing a predetermined amount of grouting material to the region around the tension
anchor which is embedded in the seabed;
following sufficient curing of the grout, introducing water into a jacking chamber
(28); and
closing a bleed valve (27) on the jacking chamber and increasing the water pressure
until the load exerted between the stressing stool and the anchor stop block has reached
the predetermined proof load; thereby stressing the or each tension anchor so as to
force the penetrating shoe into the seabed.
17. A method for installing foundations in the seabed as claimed in any one of Claims
14 to 16, the method comprising the following further steps before stressing the or
each anchor so as to force the penetrating shoe into the seabed:
adjusting the water pressure in the jacking chamber by the operating the bleed valve
and carrying out a test cycle for the or each tension anchor;
and when all anchors have been proof tested, opening the bleed valves and reducing
the load on the anchors reduced to the designed working load plus a predetermined
amount to ensure the anchor does not become un-stressed during service, which could
result in fatigue stresses in the anchors; optionally wherein the method comprises
the following further step:
introducing grout into the gap between the telescoping section of the leg and the
foundation frame or a ratchet/threaded section will be operated by a ram on the installation
and drilling frame (40).
18. A method for installing foundations in the seabed as claimed in Claim 16 wherein the
method comprises the following further steps:
when all anchor bars have been tested and preloaded, transporting the barge and lifting
frame to the deployment site;
lowering the lifting frame over the installation and drilling frames so that mechanical
coupling means engage with the lifting points on the installation and drilling frame;
engaging the mechanical coupling means so that the mechanical coupling means are opened;
winching the installation and drilling frame under the barge thereby leaving the foundation
frame connected to the seabed;
towing the barge to the load-out location and fitting the next foundation frame/anchors;
alternatively, lowering the installation and drilling frame to the sea-bed at a suitable
location;
operating the mechanical coupling means thereby disconnecting the installation drilling
frame from the lifting frame foundation frame;
recovering the lifting frame to the underside of the barge;
disconnecting the mechanical coupling means from the lifting frame and installing
the mechanical coupling means into the nacelle/electrical connection plate/alignment/installation
and drilling frame; and
winching the nacelle installation (46) and drilling frame up under the barge.
19. A method for installing foundations in the seabed as claimed in Claim 16 wherein the
method comprises the following further steps:
installing a wet-mate connection plate, j-tube with articulated joint, and a length
of export cable with a dry mate connector installed on the shore end and lifting into
alignment with the installation and drilling frame;
passing the dry-mate connector and cable end on to a vessel equipped with cabling
equipment, with the dry-mate connector and cable being spooled on to a powered drum
on the cabling vessel;
towing the deployment spread comprising a tug, deployment barge, installation and
drilling frame connectors and cable and cabling vessel (51) to the deployment location;
once close to the designated foundation frame or in a sheltered local location with
sufficient water depth on route, between this location and the foundation frame, lowering
the j-tube to vertical position;
paying out cable from the cabling vessel or moving position to keep the export cable
in the correct tension;
positioning the tug up tide from the foundation frame and hold station;
lowering the connection plate j-tube and alignment and installation and drilling frame
to a depth that the alignment guides (15) can contact the central tower;
paying out tow rope from the tug and moving the installation and drilling frame towards
the foundation frame;
operating the alignment guides to guide and centralise the connection plate over the
foundation frame tower; and
confirming the position of the j-tube and connection plate relative to the foundation
frame using sensors, cameras and sonar on the installation and drilling frame.
20. A method for installing foundations in the seabed as claimed in Claim 18 or 19 wherein
the method comprises the following further steps:
when the connection plate and j-tube are in the correct position, lowering the installation
and drilling frame and installing the connection plate and j-tube on the foundation
frame;
keeping the export cable in the correct tension by paying out cable or moving the
position of the cabling vessel;
on confirmation that the connection plate and j-tube are correctly seated, further
powering the installation and drilling frame and disconnecting from the connection
plate and j-tube;
disengaging the installation from the foundation frame;
once clear of the foundation frame, the installation and drilling frame can be recovered
and sea fastened to the barge;
optionally, the installation barge can be towed to the load out area to collect the
next connection and cabling assembly or demobilised; and
the cabling vessel can now lay the remaining cable on to the seabed or recover a pre-laid
export cable with connector to the vessel deck; the electrical and mechanical coupling
means can be formed and the cable laid on the seabed;
installing a nacelle installation and alignment frame on the deployment barge; lifting
a nacelle from the load out quay and placed in the nacelle installation alignment
frame;
optionally, alternatively a nacelle or any number of nacelles will be loaded onto
a flat top barge, placed in transport frames and transported to an intermediate laydown
area at a sheltered location, this laydown area having sufficient water depth to give
overhead clearance for the installation barge; once at the location, the nacelles
and transport frames will be lifted on top the seabed at agreed locations;
towing the installation barge to the intermediate laydown area and manoeuvring over
a nacelle and hold station over the nacelle; lowering the nacelle installation and
drilling frame from the installation barge and picking up the nacelle; and
winching the nacelle and installation and drilling frame up under the barge and sea-fastened;
towing the barge to its foundation frame location and hold station close to the tower
and removing the sea-fastenings;
lowering the installation and drilling frame so that the alignment guides on the installation
and drilling frame are low enough to contact the central tower to act as an installation
guide, but not low enough for the turbine blades to contact the tower;
letting out or recovering the tow line, connected to the installation barge, so that
alignment guides contact the central tower to guide and centralises the nacelle over
the central tower;
further lowering the nacelle/installation and drilling frame so that the nacelle aligns
and seats on the wet-mate connector plate on the on the central tower;
lowering the installation and drilling frame and disengageing from the nacelle; and
the tug will recover/let out its tow line to move the barge and so the recovery frame
away from the installed nacelle; and once clear of the foundation frame/nacelle, the
installation and drilling frame can be recovered to the barge.
1. System zur Installation eines Fundaments für eine Untersee-Struktur, wobei das System
einen Fundament-Gerüstrahmen (16) aufweist, der mit Verankerungsmitteln versehen ist,
die zumindest einen Zuganker und Mittel zum Fixieren des mindestens einen Zugankers
im Meeresgrund aufweisen; und das System auch Mittel zum Steuern des Betriebes des
Fundament-Gerüstrahmens aufweist; wobei der Fundament-Gerüstrahmen dazu bestimmt ist,
eine Apparatur, wie beispielsweise eine Energieumformapparatur zu unterstützen und
mit dieser lösbar verbunden zu sein, wobei zur Anwendung die Ankermittel dazu eingesetzt
sind, im Meeresgrund eingebettet zu werden; wobei das System einen Installations-
und Bohrrahmen aufweist, der Bohrmittel trägt; wobei der Installations- und Bohrrahmen
ein ausreichendes Gewicht vorsieht, um das System dazu zu befähigen, als Schwerkraft-Fundament
zu agieren während die Installation vollzogen wird; wobei der Installations- und Bohrrahmen
lösbar mit dem Fundament-Gerüstrahmen verbindbar ist.
2. System zur Installation eines Untersee-Fundamentes auf dem Meeresgrund gemäß Anspruch
1; wobei das System Mittel zum Vorbelasten oder Probebelasten aufweist, um die Eignungsfähigkeit
des Ankers zu testen; wobei optional die Fundament-Gerüstrahmenstruktur als die Platzierungsvorlage
für die Bohrausrüstung verwendet wird, um eine genaue Positionierung der Zuganker
zu erreichen.
3. System zur Installation eines Fundamentes für eine Untersee-Struktur nach einem vorangehenden
Anspruch, wobei die Mittel zum Einbetten des mindestens einen Zugankers den Fundament-Gerüstrahmen
umfassen; und den Installations- und Bohrrahmen; wobei optional die Fundament-Gerüstrahmenstruktur
als die Platzierungsvorlage für die Bohrausrüstung verwendet wird, um eine genaue
Positionierung der Zuganker zu erhalten; wobei optional ein einzelner Zuganker oder
mehrere Zuganker vorgesehen sind; und wobei optional der Zuganker einen hohlen Rohranker
umfasst.
4. System zur Installation eines Fundamentes für eine Untersee-Struktur nach Anspruch
3, wobei das mindestens eine Zuganker-Fundament dazu konfiguriert ist, Mittel zur
Installation des hohlen Rohrankers einzubeziehen, wobei besagte Mittel zur Installation
des Ankers in den Meeresgrund einen "down-the-hole" Bohrloch-Hammer (53) und einen
abnehmbaren Bohrkopf aufweisen.
5. System zur Installation eines Fundamentes für eine Untersee-Struktur nach einem vorangehenden
Anspruch, wobei der mindestens eine Zuganker mit Mitteln zum Einbetten des mindestens
einen Zugankers in den Meeresgrund versehen ist, wobei besagte Mittel zum Einbetten
des mindestens einen Zugankers Bohrmittel aufweisen, wobei optional die Bohrmittel
Mittel zum Bewegen eines Bohrträgers nach oben und unten eines Bohr-Mast aufweisen;
wobei optional die Mittel zum Einbetten des mindestens einen Zugankers in den Meeresgrund
ferner den Bohrträger aufweisen, auf dem ein Bohrhammer oder ein Rotations-Antriebskopf
montiert ist; wobei optional die Mittel zum Bewegen eines Bohr-Trägers nach oben und
unten eines Bohrmastes ein Fallgewicht und Umlenk-Einrichtung aufweisen, die zum Bewegen
des Bohrträgers auf und ab entlang des Bohrmastes verwendet werden; und wobei optional
der Durchmesser und/oder die Länge der Anker-Schiene und der Ankeranbindungs-Länge
in den Meeresgrund einstellbar sind, um einer großen Vielzahl von Untergrund-Gegebenheiten
zu entsprechen; und wobei optional der Fundament-Gerüstrahmen dazu bestimmt ist, eine
beliebige Anzahl von Bohrsträngen (13, 22) zu tragen.
6. System zur Installation von Fundamenten für Untersee-Strukturen gemäß einem der vorangehenden
Ansprüche, wobei das System ein Hebegerüst (42) mit geometrischen Verriegelungs-Führungen
zum Absenken und Anheben der zusammengesetzten Gerüstrahmen/des Fundament-Gerüstrahmens
an den Meeresgrund aufweist; wobei optional das Hebegerüst zum Absenken und Anheben
der zusammengesetzten Gerüstrahmen/des Fundament-Gerüstrahmens an den Meeresgrund
eine Dreipunkt-Hebeeinrichtung aufweist; wobei optional der Installations- und Bohrrahmen
Nivelliermittel aufweist, derart, dass der Installations- und Bohrrahmen auf ein Niveau
eingestellt wird durch Befehlssignale, die vom Befehlsschiff kommen; wobei optional
die Nivelliermittel eine Mehrzahl an Landungs- und Nivellierbeinen (34) aufweist,
die derart bestimmt sind, dass die Landungs-und Nivellierbeine den Meeresgrund vor
dem vom Fundament-Gerüstrahmen getragenen Bohrstrang berühren; wobei optional eine
Stoßabsorption in den Landungs-/Nivellierbeinen einbezogen ist durch Einbeziehen hydraulischer
Druckspeicher (2) und Ventilen, wodurch Stoßbelastungen auf die Senk-Ausrüstung reduziert
werden.
7. System zur Installation von Fundamenten für Untersee-Strukturen gemäß einem der vorangehenden
Ansprüche, wobei Mittel in den Fundament-Gerüstrahmenbeinen zum Einstellen der Länge
eines jeden Beins vorgesehen sind, um somit Unebenheiten oder Gefälleneigungen in
dem Meeresgrund auszugleichen; wobei optional die Mittel, die in den Fundament-Gerüstrahmenbeinen
zum Einstellen der Länge eines jeden Beins zur Kompensation der Unebenheiten oder
Gefälleneigungen in dem Meeresgrund vorgesehen sind, ein mechanisches Klinkenrad umfassen.
8. System zur Installation von Fundamenten für Untersee-Strukturen gemäß einem der Ansprüche
3 - 7, wobei der Installations- und Bohrrahmen und konsequenterweise der daran angeschlossene
Fundament-Gerüstrahmen nivelliert und bei Bedarf abgesenkt werden können, bis die
Fundament-Gerüstrahmen-Trägerplatte (19) den Meeresgrund durch Einstellen der hydraulischen
Druckströmung in den hydraulischen Druckkolben berührt, die in den Installations-
und Bohrrahmen-Beinen eingebaut sind.
9. System zur Installation von Fundamenten für Untersee-Strukturen gemäß einem der Ansprüche
3 - 8, wobei eine hydraulische Öldruck/- Strömung durch entweder hydraulische Antriebsaggregate
und Ventile, die in dem Installations- und Bohrrahmen eingebaut sind, oder durch Schlauchleitungen
von den hydraulischen Antriebsaggregaten auf dem Befehls- und Steuerschiff (37) vorgesehen
sein kann; wobei optional die Ausrichtung und Nivellierung des Fundament-Gerüstrahmens
auch bestimmt werden kann von dem Befehlsschiff, um zu bestätigen, das sich dieser
innerhalb der erforderlichen Spezifikation befindet.
10. System zur Installation von Fundamenten für Untersee-Strukturen gemäß Anspruch 5,
wobei die Bohrmittel einen Bohrstrang aufweisen, der einen hydraulischen Dreh-Hammerkopf
(5) haben, einen Eingangsanschluss zum Einführen von Spülfluid und Verfestigungs-Ankermaterial
für den Anker, ein Stopp-Mittel, das optional einen Stopp-Block auf dem Anker zum
Übertragen der Eindrück-Lasten von der Anker-Schiene an einen Last-Bodenstein (29),
eine hohle Zentrums-Anker-Schiene, eine Bohrspitze, hydraulische Klammern zum Ergreifen
des Ankers sowie ein System zum Anheben und Absenken des Bohrstranges, vorinstalliert
auf dem Installations-und Bohrgerüstrahmen; wobei optional die Stromversorgungsleitungen,
Injektionsleitungen (8) und Spülleitung (9), die zum Betreiben des Bohrsystems erforderlich
sind, innerhalb des äußeren Gehäuses unter Verwendung von einziehbaren Leitungen eingezogen
sind; wobei optional unter Verwendung des Rotations-Perkussions-Bohrhammer-Kopfes
die Bohrspitze ein Loch in dem Meeresgrund bildet und nachfolgend den Führungsschuh
(21) in den Meeresgrund antreibt, bis der Führungsschuh seinen Endhalt (32) erreicht;
wobei optional eine Schubverzahnung (31) in dem Führungsschuh (21) sodann aufbricht
oder deformiert, was der Bohrspitze und dem Anker ermöglicht, mit der Bildung des
Ankerloches fortzufahren;
wobei optional das Bohrfördermaterial aus dem Bohrloch der Bohrführung (23) ausgespült
wird und durch den Abzugskanal (26) in die Wassertiefe austritt, sowie der Anker in
den Meeresgrund eingelassen wird;
wobei optional das Spülmedium, vorzugsweise Seewasser, aus einer Wasserpumpe (12)
gefördert wird, die auf dem Installations- und Bohrrahmen montiert ist, wobei jedoch
alternativ Wasser, eine dünne Injektions-Mischung, Bohr-Morast oder Luft von dem Befehls-
und Steuerschiff ebenso für denselben Zweck gefördert werden kann; und
wobei ein Bohren optional fortgeführt wird, bis der Anhalteblock auf der Anker-Schiene
die Last-Bodenstein-Oberplatte kontaktiert.
11. System zur Installation von Fundamenten für Untersee-Strukturen nach einem der vorangehenden
Ansprüche, wobei die Anker-Schiene einen Zentralkanal aufweist, durch den ein verfestigendes
Ankermittel eingeführt werden kann, um durch den Kontrollkanal zu strömen und aus
der Anker-Schiene in den die Anker-Schiene umgebenden Bereich, wobei das Verfestigungs-Ankermaterial
von seiner Fluid-Form in eine Festform wechselt, um so die Anker-Schiene in den Meeresgrund
einzubetten, wobei optional das verfestigende Ankermaterial zementartigen Mörtel aufweist,
der in den Zentralkanal in die Anker-Schiene durch eine Mörtelleitung eingeführt wird,
wobei optional eine Ausrüstung zur chemischen Ankermittel-Dosierung, - Mischung, -Installation
mit den damit verbundenen Antriebsaggregaten, der Rohrleitung und den Ventilen auf
dem Installations- und Bohrrahmen installiert sein können.
12. System zur Installation von Fundamenten für Untersee-Strukturen nach einem vorangehenden
Anspruch, wobei die Mittel zum Einbetten des Zugankers in den Meeresgrund ferner eine
Anker-Schiene aufweisen sowie einen bewegbaren Last-Bodenstein zum Übertragen der
Last durch die Anker-Schiene in dem Verankerungspunkt auf den Meeresgrund, um den
Fundament-Gerüstrahmen-Eindringschuh (24) in den Meeresgrund zu drücken, sowie Mittel
zum Steuern der aufgebrachten Kraft.
13. System zur Installation von Fundamenten für Untersee-Strukturen nach Anspruch 12,
wobei Mörteltaschen (20) in den Grund des Fundament-Gerüstrahmens zu mechanischen
Klammer/Anschlüssen vorinstalliert sind, sowie Mittel zum Füllen der Mörteltaschen,
sodass bei Verwendung die vorinstallierten Mörteltaschen gefüllt werden können und
so jeden Leerraum, der zwischen dem Grund des Fundament-Gerüstrahmens und den Meeresboden
verbleibt, gefüllt werden kann, wobei dieser Mörtel beim Durchhärten jeglichem weiteren
Eindringen des Fundament-Gerüstrahmen-Fußes in den Meeresgrund wiedersteht und damit
einen Erosionsschutz (Ausspülung) an der Basis des Fundament-Gerüstrahmens schafft.
14. Verfahren zur Installation von Fundamenten in den Meeresgrund, wobei das Verfahren
folgende Schritte aufweist:
Vorsehen einer Apparatur zur Installation von Fundamenten für Untersee-Strukturen
mit mindestens einem Zuganker und Vorsehen der Apparatur mit Mitteln zum Einbetten
des mindestens einen Zugankers in den Meeresgrund, wobei die Apparatur einen Fundament-Gerüstrahmen
aufweist, der mit Ankermitteln versehen ist, der Fundament-Gerüstrahmen dazu bestimmt
ist, eine Ausrüstung, wie beispielsweise eine EnergieUmformapparatur, sowie die Ankermittel
zu unterstützten und mit dieser lösbar verbunden zu sein, wobei diese bei Verwendung
in dem Meeresgrund eingebettet sind; und Vorsehen der Apparatur mit einem Installations-
und Bohrrahmen, der Bohrmittel trägt, wobei der Installations- und Bohrrahmen abnehmbar
mit dem Fundament-Gerüstrahmen verbindbar ist; wobei die Mittel zum Einbetten des
mindestens einen Zugankers den Fundament-Gerüstrahmen umfassen; und den Installations-
und Bohrrahmen; und wobei optional das Verfahren ferner folgende Schritte umfasst:
Vorsehen des Zugankers als einen hohlen Rohranker, wobei das mindestens eine Zuganker-Fundament
dazu bestimmt ist, einen Bohrloch-Hammer sowie einen lösbaren Bohrkopf zur Installation
des hohlen Rohrankers in den Meeresgrund zu umfassen.
15. Verfahren zur Installation von Fundamenten in den Meeresgrund gemäß Anspruch 14, wobei
das Verfahren folgende Schritte aufweist:
Anschließen des Fundament-Gerüstrahmens an den Installations- und Bohrrahmen;
(a) Installieren des/der Bohrstränge auf dem Fundament-Gerüstrahmen; und des Installations-
und Bohrrahmens und Anheben des Fundament-Gerüstrahmens; sowie des Installations-
und Bohrrahmens mit installiertem Bohrgestänge auf dem Meeresgrund an einer geeigneten
Bauplatzierung;
(b) Manövrieren/Positionieren eines Zuleitungs-Schiffes über den Fundament-Gerüstrahmen;
und den Installations- und Bohrrahmen;
(c) Absenken eines Hebegerüsts über den Installations- und Bohrrahmen und den Fundament-Gerüstrahmen;
(d) Ausrichten des Hebegerüsts mit dem Installations- und Bohrrahmen;
(e) Betreiben von Hebevorrichtungen, sodass der Installations- und Bohrrahmen und
der Fundamentrahmen zum Aufstellen des Installations- und Bohrrahmens und des Fundament-Gerüstrahmens
an der gewünschten Stelle an einen Lastkahn (38) angeschlossen werden;
(f) Betreiben der Winden auf dem Lastkahn, um so den Installations-und Bohrrahmen
und den Fundament-Gerüstrahmen unterhalb des Lastkahns zu positionieren und die Gerüstrahmen
unterhalb des Lastkahns seefest zu machen;
(g) Übertragen der Versorgungsleitungen (50) der hydraulischen Leitungen und der Mörtelleitungen
von der Anlegerstelle und Übertrag an das Befehlsschiff;
(h) Vertäuen des Installations- und Bohrrahmens und des Fundament-Gerüstrahmens an
der Aufstellungsstelle; und
(i) Trennen der Verbindung von Meeresbefestigungen und Absenken des Fundament-Gerüstrahmens
und des Installations- und Bohrrahmens an der Aufstellungsstelle zu dem Meeresgrund
durch Betreiben des Hebegerüsts und der Winden auf dem Lastkahn; optionales Ausführen
von Bohroperationen, um so den mindestens einen Zuganker in den Meeresgrund einzubetten,
der auf dem Fundament-Gerüstrahmen vorgesehen ist; und wobei optional das Verfahren
den folgenden weiteren Schritt umfasst:
Betreiben des Schleppbootes (39), um den Lastkahn weg von der Aufstellungsstelle zu
ziehen und Platzieren des Schleppbootes zur einer der Aufstell-Platzierung fernliegenden
Stelle.
16. Verfahren zur Installation von Fundamenten in den Meeresgrund nach einem der Ansprüche
14 oder 15, wobei das Verfahren die folgenden weiteren Schritte aufweist:
Einführen einer vorbestimmten Menge an Mörtelmaterial in den Bereich um den Zuganker,
der in den Meeresgrund einzubetten ist;
ausreichendes Aushärten des Mörtels unter Einführen von Wasser in eine Rohreinpress-Kammer
(28); und
Schließen eines Entlüftungsventils (27) auf der Einpress-Kammer und Erhöhen des Wasserdruckes
bis die zwischen dem Last-Bodenstein und dem Anker-Halt-Block aufgebrachte Last die
vorbestimmte Prüfungslast erreicht hat; wodurch der oder jeder Zuganker kraftbeaufschlagt
wird, um so den Einführ-Schuh in den Meeresgrund zu treiben.
17. Verfahren zur Installation von Fundamenten in den Meeresgrund nach einem der Ansprüche
14 - 16, wobei das Verfahren die folgenden weiteren Schritte aufweist, bevor der oder
jeder Anker kraftbeaufschlagt ist, um so den Einführ-Schuh in den Meeresgrund zu treiben:
Einstellen des Wasserdrucks in der Einpress-Kammer durch Betreiben des Entlüftungsventils
und Ausführen eines Testzyklus für den oder jeden Zuganker;
und wenn alle Anker den Prüftest durchlaufen haben, Öffnen der Entlüftungsventile
und Reduzierung der Last auf die Anker und zwar reduziert auf die bemessene Arbeitslast
plus einem vorbestimmten Betrag, um sicherzustellen, dass der Anker während seinem
Dienst nicht unbelastet wird, was in den Ankern zu Ermüdungsbelastungen führen kann;
wobei optional das Verfahren ferner den folgenden Schritt aufweist:
Einführen von Mörtel in den Zwischenraum zwischen dem Teleskop-Abschnitt der Beine
und dem Fundament-Gerüstrahmen, oder es wird ein Klinkenrad/Gewindeabschnitt mittels
eines Druckkolbens auf dem Installations- und Bohrrahmen (40) genutzt.
18. Verfahren zur Installation von Fundamenten in den Meeresgrund nach Anspruch 16, wobei
das Verfahren die folgenden weiteren Schritte umfasst:
wenn alle Anker-Schienen getestet und vorbelastet wurden, Transportieren des Lastkahns
und des Hebegerüsts an die Einsatzstelle;
Absenken des Hebegerüsts über die Installations- und Bohrrahmen, sodass die mechanischen
Kopplungsmittel mit den Hebepunkten auf dem Installations- und Bohrrahmen zusammenwirken;
Anklinken der mechanischen Kopplungsmittel, sodass die mechanischen Kopplungsmittel
geöffnet werden;
Winschen des Installations- und Bohrrahmens unter den Lastkahn, wobei die Verbindung
des Fundament-Gerüstrahmens mit dem Meeresgrund verbleibt;
Anbinden des Lastkahns an die Ablageplatzierung und Anbringen des nächsten Fundament-Gerüstrahmens/-Ankers;
alternativ, Absenken des Installations- und Bohrrahmens an den Meeresgrund an eine
geeigneten Stelle;
Betätigen der mechanischen Kopplungsmittel, wodurch der Installations-Bohrrahmen von
dem Hebegerüst Fundament-Gerüstrahmen gelöst wird;
Rückgewinnung des Hebegerüsts an die Unterseite des Lastkahns;
Entkoppeln der mechanischen Kopplungsmittel von dem Hebegerüst und Installieren der
mechanischen Kopplungsmittel in den Maschinenhaus-/elektrischen Anschluss-Platte/Ausrichtung/Installations-
und Bohrrahmen; und
Winschen der Maschinenhaus-Installation (46) und des Bohrrahmens nach oben unter den
Lastkahn.
19. Verfahren zur Installation von Fundamenten in den Meeresgrund nach Anspruch 16, wobei
das Verfahren die folgenden weiteren Schritte umfasst:
Installieren einer Nass-Passungs-Anschlussplatte, j-Rohr mit Gelenk und einer Länge
eines Exportkabels mit einem Trocken-Pass-Anschluss, der auf dem Shore-Ende installiert
ist und Anheben zur Ausrichtung mit dem Installations- und Bohrrahmen;
Überführen des Trocken-Pass-Anschlusses und des Kabelendes an ein Schiff, das mit
einer Kabelausrüstung ausgerüstet ist, wobei der Trocken-Pass-Anschluss und das Kabel
auf einer Antriebs-Trommel auf dem Verkabelungsschiff aufgewickelt sind;
Schleppen des Aufstell-Umfeldes unter Einbezug eines Schlepp-Kahns, eines Aufstell-Lastkahns,
Installations- und Bohrrahmen-Anschlüssen und der Kabel und eines Verkabelungsschiffes
(51) an die Aufstellstelle;
Absenken des j-Rohrs in eine vertikale Position entweder nahe zu dem bestimmten Fundament-Gerüstrahmen
oder in einer geschützten Platzierungsstelle mit einer ausreichenden Wasser-Fahrtiefe
zwischen dieser Lokation und dem Fundament-Gerüstrahmen;
Abrollen von Kabel von dem Verkabelungsschiff oder Ändern der Position, um das Export-Kabel
in der korrekten Spannung zu halten;
Positionieren des Schleppschiffes stromaufwärts zum Fundament-Gerüstrahmen und der
Haltestation;
Absenken des Anschlussplatten-j-Rohres und Ausrichten und Installieren und Bohrrahmen
auf eine Tiefe, dass die Ausrichtführungen (15) den Zentralturm kontaktieren können;
Abwickeln des Vertäuungs-Seiles von dem Schlepper und Bewegen des Installations- und
Bohrrahmens in Richtung zum Fundament-Gerüstrahmen;
Betreiben der Ausricht-Führungen zum Führen und Zentralisieren der Anschlussplatte
über den Fundament-Gerüstrahmen-Turm; und
Bestätigen der Position des j-Rohres und der Anschlussplatte relativ zu dem Fundament-Gerüstrahmen
unter Verwendung von Sensoren, Kameras und Ultraschall auf dem Installations- und
Bohrrahmen.
20. Verfahren zur Installation von Fundamenten in dem Meeresgrund nach Anspruch 18 oder
19, wobei das Verfahren die folgenden weiteren Schritte umfasst:
wenn die Anschlussplatte und das j-Rohr in der korrekten Position sind, Absenken des
Installations- und Bohrrahmens und Installieren der Anschlussplatte und des j-Rohres
auf den Fundament-Gerüstrahmen;
Halten des Export-Kabels in der korrekten Spannung durch Abwickeln von Kabel oder
Ändern der Position des Verkabelungs-Schiffes;
nach Bestätigung, dass die Anschlussplatte und das j-Rohr korrekt eingesetzt sind,
ferner Antreiben des Installations- und Bohrrahmens und Lösen von der Anschlussplatte
und dem j-Rohr
Entkoppeln der Installation von dem Fundament-Gerüstrahmen
nach Abtrennen des Fundament-Gerüstrahmens kann der Installations-und Bohrrahmen rückgewonnen
und an den Lastkahn unter Wasser festgelegt werden;
optional kann der Installations-Schlepper an dem Aufladebereich vertäut werden, um
den nächsten Anschluss mit Verkabelungseinrichtung aufzunehmen oder ihn zu demobilisieren;
und
das Verkabelungsschiff kann nun das verbleibende Kabel auf den Meeresgrund ablegen
oder ein vorabgelegtes Exportkabel mit Anschluss an das Schiffsdeck rückgewinnen;
die elektrischen und mechanischen Verkopplungsmittel können formiert und das Kabel
auf dem Meeresgrund abgelegt werden;
Installieren einer Maschinenhaus-Installation und eines Ausricht-Gerüstrahmens an
dem Vorort-Lastkahn; Anheben eines Maschinenhauses von der Ablade-Anlegestelle platziert
in dem Maschinenhaus-Installations-Ausrichtrahmen; optional alternativ wird ein Maschinenhaus
oder irgendeine Anzahl an Maschinenhäusern auf einen flachen Top-Lastkahn geladen,
platziert in Transportrahmen und an einen Zwischenabladebereich an einer geschützten
Platzierung, wobei dieser Abladebereich eine ausreichende Wassertiefe hat um einen
oberirdischen Zwischenraum für den Installations-Lastkahn zur Verfügung zu stellen;
bei Erreichen der Platzierung werden die Maschinenräume und Transportrahmen oben auf
dem Meeresgrund zu vorbestimmten Stellen gehoben;
Vertäuen des Installations-Lastkahns an den Zwischen-Abladebereich und Manövrieren
über einen Maschinenraum und einer Haltestation über den Maschinenraum; Absenken der
Maschinenrauminstallation und des Bohrrahmens von dem Installations-Lastkahn und Aufnehmen
des Maschinenraums; und
Winden des Maschinenraums und des Installations- und Bohrrahmens unter den Lastkahn
mit einer Unterwasserbefestigung;
Vertäuen des Lastkahns an dessen Fundament-Gerüstrahmenplatzierung und Haltestation
nahe zu dem Tower und Entfernen von Seebefestigungen;
Absenken des Installations- und Bohrrahmens, sodass die Ausricht-Führungen auf dem
Installations- und Bohrrahmen niedrig genug sind, um den zentralen Tower zu kontaktieren,
um so als eine Installationsführung zu wirken, jedoch nicht tief genug, dass die Turbinenklingen
den Tower kontaktieren;
Ablassen oder Rückgewinnung der Vertäuungs-Leitung, angeschlossen an den Installations-Lastkahn,
sodass Ausrichtführungen den zentralen Tower kontaktieren, um den Maschinenraum über
den zentralen Tower zu zentrieren;
ferner Absenken des Maschineraums/der Installation und Bohrrahmen sodass der Maschinenraum
ausgerichtet ist und auf der Nass-Passung-Anschlussplatte auf dem zentralen Tower
sitzt;
Absenken des Installations- und Bohrrahmens und Lösen von dem Maschinenraum; und des
Schleppschiffes Rückgewinnen/Auslassen dessen Vertäuungsleitung zur Bewegung des Schleppkahns
und somit Rückgewinnen des Gerüstrahmens weg von dem installierten Maschinenraum;
und nach Abtrennen des Fundament-Gerüstrahmens/Maschinenraums kann der Installations-
und Bohrrahmen für den Lastkahn zurückgewonnen werden.
1. Système pour installer une fondation pour une structure sous-marine, dans lequel le
système comprend un bâti de fondation (16) qui est prévu avec des moyens d'ancrage
comprenant au moins une ancre de tension et des moyens pour fixer ladite au moins
une ancre de tension dans le plancher océanique ; et le système comprenant également
des moyens pour commander le fonctionnement du bâti de fondation ; le bâti de fondation
étant adapté pour supporter et être raccordé de manière amovible avec l'appareil tel
qu'un appareil de conversion d'énergie, dans lequel, à l'usage, le moyen d'ancrage
est actionné pour être encastré dans le plancher océanique ; dans lequel le système
comprend un bâti d'installation et de forage portant des moyens de forage ; le bâti
d'installation et de forage fournissant le poids suffisant pour permettre au système
de servir de fondation de gravité alors que l'installation a lieu ; le bâti d'installation
et de forage pouvant être raccordé de manière amovible au bâti de fondation.
2. Système pour installer une fondation sous-marine sur le plancher océanique selon la
revendication 1 ; dans lequel le système comprend des moyens pour le pré-chargement
ou la charge d'essai afin de tester le caractère approprié de l'ancre ; facultativement,
dans lequel la structure de bâti de fondation est utilisée en tant que gabarit de
positionnement pour l'équipement de forage afin d'obtenir le positionnement précis
des ancres de tension.
3. Système pour installer une fondation pour une structure sous-marine selon l'une quelconque
des revendications précédentes, dans lequel les moyens pour encastrer ladite au moins
une ancre de tension comprend le bâti de fondation ; et le bâti d'installation et
de forage ; facultativement dans lequel la structure de bâti de fondation est utilisée
en tant que gabarit de positionnement pour l'équipement de forage afin d'obtenir le
positionnement précis des ancres de tension ; facultativement dans lequel on prévoit
une seule ancre de tension ou plusieurs ancres de tension ; et facultativement dans
lequel l'ancre de tension comprend une ancre tubulaire creuse.
4. Système pour installer une fondation pour une structure sous-marine selon la revendication
3, dans lequel la au moins une fondation d'ancre de tension est configurée pour comprendre
des moyens pour l'installation de l'ancre tubulaire creuse, lesdits moyens pour l'installation
de l'ancre dans le plancher océanique comprend un pilon (53) de « fond de trou » et
une tête de forage détachable.
5. Système pour installer une fondation pour une structure sous-marine selon l'une quelconque
des revendications précédentes, dans lequel la au moins une ancre de tension est prévue
avec des moyens pour encastrer ladite au moins une ancre de tension dans le plancher
océanique, lesdits moyens pour encastrer la au moins une ancre de tension comprenant
des moyens de forage, facultativement dans lequel le moyen de forage comprenant des
moyens pour déplacer un chariot de forage vers le haut et vers le bas d'un mât de
forage ; facultativement dans lequel le moyen pour encastrer ladite au moins une ancre
de tension dans le plancher océanique comprend en outre le chariot de forage sur lequel
un perforateur de forage ou tête d'entraînement rotative est monté(e) ; facultativement
dans lequel le moyen pour déplacer un chariot de forage vers le haut et vers le bas
d'un mât de forage comprend un agencement de vérin et de poulie utilisé pour déplacer
le chariot de forage vers le haut et vers le bas d'un mât de forage ; et facultativement
dans lequel le diamètre et/ou la longueur de la barre d'ancrage et de la longueur
de liaison dans le plancher océanique peut être ajusté(e) pour convenir à toute une
variété de conditions de sol ; et facultativement dans lequel le bâti de fondation
est adapté pour porter n'importe quel nombre de garnitures de forage (13, 22).
6. Système pour installer des fondations pour des structures sous-marines selon l'une
quelconque des revendications précédentes, dans lequel le système comprend un bâti
de levage (42) avec des guides se verrouillant de manière géométrique pour abaisser
et lever les bâtis assemblés/bâti de fondation par rapport au plancher océanique ;
facultativement dans lequel le bâti de levage pour abaisser et lever les bâtis assemblés/bâti
de fondation par rapport au plancher océanique comprend un agencement de levage à
trois points ; facultativement dans lequel le bâti d'installation et de forage comprend
des moyens de mise à niveau de sorte que le bâti d'installation et de forage est ajusté
au niveau par des signaux de commande communiqués à partir du navire de commande ;
facultativement dans lequel les moyens de mise à niveau comprenant une pluralité de
jambes d'atterrissage et de mise à niveau (34) adaptées de sorte que les jambes d'atterrissage
et de mise à niveau touchent le plancher océanique avant la garniture de forage portée
sur le bâti de fondation ; facultativement dans lequel un amortisseur est incorporé
dans les jambes d'atterrissage/mise à niveau en incorporant des accumulateurs hydrauliques
(2) et des soupapes réduisant ainsi les charges de choc sur l'équipement d'abaissement.
7. Système pour installer des fondations pour des structures sous-marines selon l'une
quelconque des revendications précédentes, dans lequel on prévoit des moyens dans
les jambes de bâti de fondation pour ajuster la longueur de chaque jambe afin de compenser
l'irrégularité ou les inclinaisons dans le plancher océanique ; facultativement dans
lequel les moyens prévus dans les jambes de bâti de fondation pour ajuster la longueur
de chaque jambe afin de compenser l'irrégularité ou les inclinaisons dans le plancher
océanique comprennent un rochet mécanique.
8. Système pour installer des fondations pour des structures sous-marines selon l'une
quelconque des revendications 3 à 7, dans lequel le bâti d'installation et de fondation
et par conséquent le bâti de fondation auquel il est raccordé, peut être mis à niveau
et si nécessaire, abaissé jusqu'à ce que la plaque de support de bâti (19) touche
le plancher océanique en ajustant l'écoulement de pression hydraulique dans les vérins
hydrauliques encastrés dans les jambes de bâti d'installation et de forage.
9. Système pour installer des fondations pour des structures sous-marines selon l'une
quelconque des revendications 3 à 8, dans lequel la pression/écoulement d'huile hydraulique
peut être amené(e) par des blocs d'alimentation hydrauliques et des valves encastrés
dans le bâti d'installation et de forage ou par le biais de tuyaux flexibles à partir
des blocs d'alimentation hydrauliques sur la navire de commande et de contrôle (37)
; facultativement dans lequel l'alignement et le niveau du bâti de fondation peuvent
également être déterminés à partir du navire de commande pour confirmer qu'il est
dans la spécification requise.
10. Système pour installer des fondations pour des structures sous-marines selon la revendication
5, dans lequel les moyens de forage comprennent une garniture de forage comprenant
une tête de perforateur rotative hydraulique (5), un orifice d'entrée pour introduire
le fluide de rinçage et solidifier le matériau des ancres sur l'ancre, un moyen de
butée comprenant facultativement un bloc de butée sur l'ancre afin de transférer les
charges de vérinage de la barre d'ancrage à un tabouret de mise sous contrainte (29),
une barre d'ancrage creuse, un trépan, des pinces hydrauliques pour saisir l'ancre
et un système pour lever et abaisser la garniture de forage est préinstallé sur le
bâti d'installation et de forage ; facultativement, les conduites d'alimentation,
les conduites de mortier liquide (8) et la conduite de rinçage (9) nécessaires pour
actionner le système de forage sont triées à l'intérieur du boîtier externe à l'aide
de câbles rétractables ;
facultativement, en utilisant la tête de perforateur à percussion rotative, le trépan
forme un trou dans le plancher océanique et entraîne simultanément le sabot conducteur
(21) dans le plancher océanique jusqu'à ce que le sabot conducteur atteigne sa butée
d'extrémité (32) ;
facultativement, des clavettes de cisaillement (31) dans le sabot conducteur se cassent
ou se déforment ensuite, permettant au trépan et à l'ancre de continuer à former le
trou d'ancre ;
facultativement, étant donné que l'ancre est forée dans le plancher océanique, les
gisements de forage sont nettoyés hors du trou foré le long du conducteur de forage
(23) et sortent par le conduit d'échappement (26) dans la colonne d'eau ;
facultativement, le milieu de rinçage, de préférence l'eau de mer, est amené à partir
d'une pompe à eau (12) montée sur le bâti d'installation et de forage mais en variante
de l'eau, un mélange de mortier liquide léger, de la boue de forage ou de l'air provenant
du navire de commande et de contrôle peut également être fourni(e) pour la même fonction
; et
facultativement, le forage continue jusqu'à ce que le bloc de butée sur la barre d'ancrage
soit en contact avec la plaque supérieure de tabouret de mise sous contrainte.
11. Système pour installer des fondations pour des structures sous-marines selon l'une
quelconque des revendications précédentes, dans lequel la barre d'ancrage comprend
un canal central à travers lequel un matériau d'ancrage de solidification peut être
introduit afin de s'écouler à travers le canal de commande et hors de la barre d'ancrage
dans la zone entourant la barre d'ancrage où le matériau d'ancrage de solidification
passe de la forme fluide à la forme solide afin d'encastrer la barre d'ancrage dans
le plancher océanique, facultativement dans lequel le matériau d'ancrage de solidification
comprend un mortier liquide à base de ciment qui est introduit dans le canal central
dans la barre d'ancrage par une conduite de mortier liquide ; facultativement dans
lequel on peut installer un équipement de dosage d'ancre chimique, de mélange, d'installation
avec les blocs d'alimentations associés, la tuyauterie et les valves sur le bâti d'installation
et de forage.
12. Système pour installer des fondations pour des structures sous-marines selon l'une
quelconque des revendications précédentes, dans lequel le moyen pour encastrer l'ancre
de tension dans le plancher océanique comprend en outre un bloc de butée sur la barre
d'ancrage et un tabouret de mise sous contrainte mobile pour transférer la charge
par la barre d'ancrage dans le point d'ancrage sur le plancher océanique de manière
efficace pour forcer le sabot de pénétration de bâti de fondation (24) dans le plancher
océanique et des moyens pour contrôler la force appliquée.
13. Système pour installer des fondations pour des structures sous-marines selon la revendication
12, dans lequel des sacs de mortier liquide (20) sont préinstallés au fond du bâti
de fondation au niveau d'une pince/raccordement mécanique et des moyens pour faire
gonfler les sacs de mortier liquide sont prévus de sorte qu'à l'usage, les sacs de
mortier liquide préinstallés peuvent être gonflés et ainsi remplir les vides restant
entre le fond du bâti de fondation et le plancher océanique, moyennant quoi ce mortier
liquide, lorsqu'il a durci, résiste à toute autre pénétration du pied de bâti de fondation
dans le plancher océanique et fournit la protection contre l'affouillement (érosion)
à la base du bâti de fondation.
14. Procédé pour installer des fondations dans le plancher océanique, le procédé comprenant
l'étape suivante consistant à:
prévoir un appareil pour installer des fondations sur des structures sous-marines
avec au moins une ancre de tension et doter l'appareil de moyens pour encastrer ladite
au moins une ancre de tension dans le plancher océanique, l'appareil comprenant un
bâti de fondation qui est prévu avec des moyens d'ancrage, le bâti de fondation étant
adapté pour supporter et être raccordé de manière amovible à l'équipement tel qu'un
appareil de conversion d'énergie et les moyens d'ancrage, à l'usage, étant encastrés
dans le plancher océanique ; et doter l'appareil d'un moyen de forage portant le bâti
d'installation et de forage ; le bâti d'installation et de forage pouvant être raccordé
de manière amovible au bâti de fondation ; le moyen pour encastrer ladite au moins
une ancre de tension comprend le bâti de fondation ; et le bâti d'installation et
de forage ; facultativement dans lequel le procédé comprend également l'étape suivante
consistant à :
prévoir l'ancre de tension sous la forme d'une ancre tubulaire creuse, dans lequel
la au moins une fondation d'ancre de tension est configurée pour comprendre un pilon
de « fond de trou » et une tête de forage détachable pour l'installation de l'ancre
tubulaire creuse dans le plancher océanique.
15. Procédé pour installer des fondations dans le plancher océanique selon la revendication
13, le procédé comprenant les étapes suivantes consistant à :
raccorder le bâti de fondation au bâti d'installation et de forage ;
(a) installer la (les) garniture(s) de forage sur le bâti de fondation ; et le bâti
d'installation et de forage et lever le bâti de fondation ; et le bâti d'installation
et de forage avec la (les) garniture(s) de forage installée(s), sur le plancher océanique
à un emplacement abrité approprié ;
(b) manoeuvrer/positionner un navire de pose sur le bâti de fondation ; et le bâti
d'installation et de forage ;
(c) abaisser un bâti de levage sur le bâti d'installation et de forage et le bâti
de fondation ;
(d) aligner le bâti de levage avec le bâti d'installation et de forage ;
(e) actionner les dispositifs de levage de sorte que le bâti d'installation et de
forage et le bâti de fondation sont raccordés à une barge (38) pour déployer le bâti
d'installation et de forage et le bâti de fondation sur le site souhaité ;
(f) actionner les treuils sur la barge afin de positionner le bâti d'installation
et de forage et le bâti de fondation sous la barge et fixer en mer les bâtis sous
la barge ;
(g) transférer les conduites ombilicales (50), les conduites hydrauliques et les conduites
de mortier liquide depuis le bord du quai et transférées au navire de commande ;
(h) remorquer le bâti d'installation et de forage et le bâti de fondation à l'emplacement
de déploiement ; et
(i) à l'emplacement de déploiement, déconnecter les fixations en mer et abaisser le
bâti de fondation et le bâti d'installation et de forage vers le plancher océanique
en actionnant le bâti de levage et les treuils sur la barge ; facultativement réaliser
l'opération de forage afin d'encastrer dans le plancher océanique, la au moins une
ancre de tension prévue sur le bâti de fondation ; et facultativement le procédé comprenant
l'étape supplémentaire suivante : actionner le remorqueur (39) pour éloigner la barge
du site de déploiement et avoir le remorqueur en attente à un emplacement à distance
de l'emplacement de déploiement.
16. Procédé pour installer des fondations dans le plancher océanique selon l'une quelconque
des revendications 14 ou 15, le procédé comprenant les étapes supplémentaires suivantes
consistant à :
introduire une quantité prédéterminée de matériau de mortier liquide dans la région
autour de l'ancre de tension qui est encastrée dans le plancher océanique ;
suite au durcissement suffisant du mortier liquide, introduire de l'eau dans une chambre
de vérinage (28) ; et
fermer une valve de purge (27) sur la chambre de vérinage et augmenter la pression
d'eau jusqu'à ce que la charge exercée entre le tabouret de mise sous contrainte et
le bloc de butée d'ancre ait atteint la charge d'essai prédéterminée ; mettant ainsi
sous contrainte la ou chaque ancre de tension afin de forcer le sabot de pénétration
dans le plancher océanique.
17. Procédé pour installer des fondations dans le plancher océanique selon l'une quelconque
des revendications 14 à 16, le procédé comprenant les étapes supplémentaires suivantes
avant de mettre sous contrainte la ou chaque ancre afin de forcer le sabot de pénétration
dans le plancher océanique, consistant à :
ajuster la pression d'eau dans la chambre de vérinage par l'actionnement de la valve
de purge et réaliser un cycle de test pour la ou chaque ancre de tension ;
et lorsque toutes les ancres ont été soumises à des essais, ouvrir les valves de purge
et réduire la charge sur les ancres réduite à la charge de travail conçue plus une
quantité prédéterminée pour garantir que l'ancre ne soit pas détendue pendant le service,
ce qui peut se traduire par les contraintes de fatigue dans les ancres ; facultativement
dans lequel le procédé comprend l'étape supplémentaire suivante consistant à :
introduire le mortier liquide dans l'espace situé entre la section télescopique de
la jambe et le bâti de fondation ou une section à rochet/filetée est actionné(e) par
un vérin sur le bâti d'installation et de forage (40).
18. Procédé pour installer des fondations dans le plancher océanique selon la revendication
16, dans lequel le procédé comprend les étapes supplémentaires suivantes consistant
à :
lorsque toutes les barres d'ancrage ont été testées et pré-chargées, transporter la
barge et le bâti de levage vers le site de déploiement ;
abaisser le bâti de levage sur les bâtis d'installation et de forage de sorte que
les moyens de couplage mécanique se mettent en prise avec les points de levage sur
le bâti d'installation et de forage ;
mettre en prise les moyens de couplage mécanique de sorte que les moyens de couplage
mécanique sont ouverts ;
remonter avec un treuil le bâti d'installation et de forage sous la barge laissant
ainsi le bâti de fondation raccordé au plancher océanique ;
remorquer la barge à l'emplacement de déchargement et monter le bâti de fondation/ancres
suivant(es) ;
en variante, abaisser le bâti d'installation et de forage par rapport au plancher
océanique à un emplacement approprié ;
actionner les moyens de couplage mécanique, déconnectant ainsi le bâti d'installation
et de forage du bâti de fondation de bâti de levage ;
récupérer le bâti de levage de sous la barge ;
déconnecter les moyens de couplage mécanique du bâti de levage et installer les moyens
de coulage mécanique dans le bâti d'installation et de forage/alignement/plaque de
raccordement de nacelle/électrique ; et
remonter avec un treuil l'installation de nacelle (46) et le bâti de forage jusque
sous la barge.
19. Procédé pour installer des fondations dans le plancher océanique selon la revendication
16, dans lequel le procédé comprend les étapes supplémentaires suivantes consistant
à :
installer une plaque de raccordement à couplage humide, un tube en J avec un joint
articulé, et une longueur de câble d'exportation avec un connecteur à couplage sec
installé sur l'extrémité du côté de la rive et lever en alignement avec le bâti d'installation
et de forage ;
faire passer le connecteur à couplage sec et l'extrémité de câble sur un navire équipé
avec un équipement de câblage, avec le connecteur à couplage sec et le câble qui sont
embobinés sur un tambour électrique sur le navire de câblage ;
remorquer le chantier de pose de déploiement comprenant un remorqueur, une barge de
déploiement, des connecteurs et câble de bâti d'installation et de forage et un navire
de câblage (51) jusqu'à l'emplacement de déploiement ;
une fois à proximité du bâti de fondation désigné ou dans un emplacement local abrité
avec une profondeur d'eau suffisante sur voie, entre cet emplacement et le bâti de
fondation, abaisser le tube en J dans la position verticale ;
dérouler le câble à partir du navire de câblage ou changer de position pour maintenir
le câble d'exportation à la bonne tension ;
positionner le remorqueur à marée haute à partir du bâti de fondation et d'une station
de maintient ;
abaisser le tube en J de plaque de raccordement et le bâti d'alignement et d'installation
et de forage à une profondeur dans laquelle les guides d'alignement (15) peuvent être
en contact avec la tour centrale ;
dérouler le câble de remorquage à partir du remorqueur et déplacer le bâti d'installation
et de forage vers le bâti de fondation ;
actionner les guides d'alignement pour guider et centraliser la plaque de raccordement
sur la tour de bâti de fondation ; et
confirmer la position du tube en J et de la plaque de raccordement par rapport au
bâti de fondation à l'aide de capteurs, de caméras et de sonar sur le bâti d'installation
et de forage.
20. Procédé pour installer des fondations dans le plancher océanique selon la revendication
18 ou 19, dans lequel le procédé comprend les étapes supplémentaires suivantes consistant
à :
lorsque la plaque de raccordement et le tube en J sont dans la position correcte,
abaisser le bâti d'installation et de forage et installer la plaque de raccordement
et le tube en J sur le bâti de fondation ;
maintenir le câble d'exportation à la tension correcte en déroulant le câble ou en
changeant la position du navire de câblage ;
suite à la confirmation que la plaque de raccordement et le tube en J sont correctement
installés, alimenter en outre le bâti d'installation et de forage et déconnecter la
plaque de raccordement et le tube en J ;
dégager l'installation du bâti de fondation ;
une fois débarrassé du bâti de fondation, le bâti d'installation et de forage peut
être récupéré et fixé en mer sur la barge ;
facultativement, la barge d'installation peut être remorquée jusqu'à la zone de déchargement
pour collecter le prochain ensemble de raccordement et de câblage ou démobilisée ;
et
le navire de câblage peut maintenant poser le câble résiduel sur le plancher océanique
ou récupérer un câble d'exportation pré-posé avec le connecteur au pont du navire
; les moyens de couplage électrique et mécanique peuvent être formés et le câble posé
sur le plancher océanique ;
installer un bâti d'installation et d'alignement de nacelle sur la barge de déploiement
; lever une nacelle du quai de déchargement et placée dans le bâti d'alignement et
d'installation de nacelle ;
facultativement en variante une nacelle ou n'importe quel nombre de nacelles est chargée(s)
sur une barge plate, placée dans des bâtis de transport et transportée(s) vers une
zone de pose intermédiaire à un emplacement à l'abri, cette zone de pose ayant une
profondeur d'eau suffisante pour donner une hauteur libre pour la barge d'installation
; une fois à l'emplacement, les nacelles et les bâtis de transport sont levés sur
le dessus du fond océanique aux emplacements approuvés ;
remorquer la barge d'installation à la zone de pose intermédiaire et manoeuvrer sur
une station de nacelle et de maintient sur la nacelle ; abaisser le bâti d'installation
et de forage de nacelle depuis la barge et ramasser la nacelle ; et
ramener le bâti d'installation et de forage et de nacelle jusque sous la barge et
le fixer en mer ;
remorquer la barge jusqu'à l'emplacement de bâti de fondation et la station de maintient
à proximité de la tour et retirer les fixations en mer ;
abaisser le bâti d'installation et de forage de sorte que les guides d'alignement
sur le bâti d'installation et de forage sont assez bas pour être en contact avec la
tour centrale pour servir de guides d'installation, mais pas assez bas pour que les
pales de turbine soient en contact avec la tour ;
lâcher ou récupérer la ligne de remorquage, raccordée à la barge d'installation, de
sorte que les guides d'alignement sont en contact avec la tour centrale pour guider
et centraliser la nacelle sur la tour centrale ;
abaisser en outre la nacelle/bâti d'installation et de forage de sorte que la nacelle
s'aligne et s'installe sur le plaque de connecteur à couplage humide sur la tour centrale
;
abaisser le bâti d'installation et de forage et dégager de la nacelle ; et le remorqueur
récupère/lâche la ligne de remorquage pour déplacer la barge et ainsi le bâti de récupération
à distance de la nacelle installée ; et une fois débarrassé du bâti de fondation/nacelle,
le bâti d'installation et de forage peut être récupéré sur la barge.