WO2020005066A1 - Method for installation of an offshore structure using one or more cranes - Google Patents

Method for installation of an offshore structure using one or more cranes Download PDF

Info

Publication number
WO2020005066A1
WO2020005066A1 PCT/NL2019/050398 NL2019050398W WO2020005066A1 WO 2020005066 A1 WO2020005066 A1 WO 2020005066A1 NL 2019050398 W NL2019050398 W NL 2019050398W WO 2020005066 A1 WO2020005066 A1 WO 2020005066A1
Authority
WO
WIPO (PCT)
Prior art keywords
wires
lifting
base
supports
lower supports
Prior art date
Application number
PCT/NL2019/050398
Other languages
French (fr)
Inventor
Leon OVERDULVE
Stefan VAN MIERLO
Thijs NAGTEGAAL
Roel DIEKERHOF
Original Assignee
Holding Oos Ii B.V.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Holding Oos Ii B.V. filed Critical Holding Oos Ii B.V.
Publication of WO2020005066A1 publication Critical patent/WO2020005066A1/en

Links

Classifications

    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02B—HYDRAULIC ENGINEERING
    • E02B17/00—Artificial islands mounted on piles or like supports, e.g. platforms on raisable legs or offshore constructions; Construction methods therefor
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B66—HOISTING; LIFTING; HAULING
    • B66C—CRANES; LOAD-ENGAGING ELEMENTS OR DEVICES FOR CRANES, CAPSTANS, WINCHES, OR TACKLES
    • B66C1/00—Load-engaging elements or devices attached to lifting or lowering gear of cranes or adapted for connection therewith for transmitting lifting forces to articles or groups of articles
    • B66C1/10—Load-engaging elements or devices attached to lifting or lowering gear of cranes or adapted for connection therewith for transmitting lifting forces to articles or groups of articles by mechanical means
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B66—HOISTING; LIFTING; HAULING
    • B66C—CRANES; LOAD-ENGAGING ELEMENTS OR DEVICES FOR CRANES, CAPSTANS, WINCHES, OR TACKLES
    • B66C1/00—Load-engaging elements or devices attached to lifting or lowering gear of cranes or adapted for connection therewith for transmitting lifting forces to articles or groups of articles
    • B66C1/10—Load-engaging elements or devices attached to lifting or lowering gear of cranes or adapted for connection therewith for transmitting lifting forces to articles or groups of articles by mechanical means
    • B66C1/108—Load-engaging elements or devices attached to lifting or lowering gear of cranes or adapted for connection therewith for transmitting lifting forces to articles or groups of articles by mechanical means for lifting parts of wind turbines
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B66—HOISTING; LIFTING; HAULING
    • B66C—CRANES; LOAD-ENGAGING ELEMENTS OR DEVICES FOR CRANES, CAPSTANS, WINCHES, OR TACKLES
    • B66C1/00—Load-engaging elements or devices attached to lifting or lowering gear of cranes or adapted for connection therewith for transmitting lifting forces to articles or groups of articles
    • B66C1/10—Load-engaging elements or devices attached to lifting or lowering gear of cranes or adapted for connection therewith for transmitting lifting forces to articles or groups of articles by mechanical means
    • B66C1/42—Gripping members engaging only the external or internal surfaces of the articles
    • B66C1/44—Gripping members engaging only the external or internal surfaces of the articles and applying frictional forces
    • B66C1/54—Internally-expanding grippers for handling hollow articles
    • B66C1/56—Internally-expanding grippers for handling hollow articles for handling tubes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B66—HOISTING; LIFTING; HAULING
    • B66C—CRANES; LOAD-ENGAGING ELEMENTS OR DEVICES FOR CRANES, CAPSTANS, WINCHES, OR TACKLES
    • B66C1/00—Load-engaging elements or devices attached to lifting or lowering gear of cranes or adapted for connection therewith for transmitting lifting forces to articles or groups of articles
    • B66C1/10—Load-engaging elements or devices attached to lifting or lowering gear of cranes or adapted for connection therewith for transmitting lifting forces to articles or groups of articles by mechanical means
    • B66C1/62—Load-engaging elements or devices attached to lifting or lowering gear of cranes or adapted for connection therewith for transmitting lifting forces to articles or groups of articles by mechanical means comprising article-engaging members of a shape complementary to that of the articles to be handled
    • B66C1/66—Load-engaging elements or devices attached to lifting or lowering gear of cranes or adapted for connection therewith for transmitting lifting forces to articles or groups of articles by mechanical means comprising article-engaging members of a shape complementary to that of the articles to be handled for engaging holes, recesses, or abutments on articles specially provided for facilitating handling thereof
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B66—HOISTING; LIFTING; HAULING
    • B66C—CRANES; LOAD-ENGAGING ELEMENTS OR DEVICES FOR CRANES, CAPSTANS, WINCHES, OR TACKLES
    • B66C23/00—Cranes comprising essentially a beam, boom, or triangular structure acting as a cantilever and mounted for translatory of swinging movements in vertical or horizontal planes or a combination of such movements, e.g. jib-cranes, derricks, tower cranes
    • B66C23/18—Cranes comprising essentially a beam, boom, or triangular structure acting as a cantilever and mounted for translatory of swinging movements in vertical or horizontal planes or a combination of such movements, e.g. jib-cranes, derricks, tower cranes specially adapted for use in particular purposes
    • B66C23/36—Cranes comprising essentially a beam, boom, or triangular structure acting as a cantilever and mounted for translatory of swinging movements in vertical or horizontal planes or a combination of such movements, e.g. jib-cranes, derricks, tower cranes specially adapted for use in particular purposes mounted on road or rail vehicles; Manually-movable jib-cranes for use in workshops; Floating cranes
    • B66C23/52—Floating cranes
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02B—HYDRAULIC ENGINEERING
    • E02B17/00—Artificial islands mounted on piles or like supports, e.g. platforms on raisable legs or offshore constructions; Construction methods therefor
    • E02B17/02—Artificial islands mounted on piles or like supports, e.g. platforms on raisable legs or offshore constructions; Construction methods therefor placed by lowering the supporting construction to the bottom, e.g. with subsequent fixing thereto
    • E02B17/027—Artificial islands mounted on piles or like supports, e.g. platforms on raisable legs or offshore constructions; Construction methods therefor placed by lowering the supporting construction to the bottom, e.g. with subsequent fixing thereto steel structures
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02B—HYDRAULIC ENGINEERING
    • E02B17/00—Artificial islands mounted on piles or like supports, e.g. platforms on raisable legs or offshore constructions; Construction methods therefor
    • E02B2017/0039—Methods for placing the offshore structure
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F03—MACHINES OR ENGINES FOR LIQUIDS; WIND, SPRING, OR WEIGHT MOTORS; PRODUCING MECHANICAL POWER OR A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR
    • F03D—WIND MOTORS
    • F03D13/00—Assembly, mounting or commissioning of wind motors; Arrangements specially adapted for transporting wind motor components
    • F03D13/10—Assembly of wind motors; Arrangements for erecting wind motors
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F03—MACHINES OR ENGINES FOR LIQUIDS; WIND, SPRING, OR WEIGHT MOTORS; PRODUCING MECHANICAL POWER OR A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR
    • F03D—WIND MOTORS
    • F03D13/00—Assembly, mounting or commissioning of wind motors; Arrangements specially adapted for transporting wind motor components
    • F03D13/20—Arrangements for mounting or supporting wind motors; Masts or towers for wind motors
    • F03D13/25—Arrangements for mounting or supporting wind motors; Masts or towers for wind motors specially adapted for offshore installation
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05B—INDEXING SCHEME RELATING TO WIND, SPRING, WEIGHT, INERTIA OR LIKE MOTORS, TO MACHINES OR ENGINES FOR LIQUIDS COVERED BY SUBCLASSES F03B, F03D AND F03G
    • F05B2230/00—Manufacture
    • F05B2230/60—Assembly methods
    • F05B2230/61—Assembly methods using auxiliary equipment for lifting or holding
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

Definitions

  • the present invention relates to a method for lifting a constructional structure of an offshore platform using one or more cranes at an offshore location.
  • a constructional structure is herein defined as a structure that is part of, or is to form part of, the offshore platform, has a weight of at least 100000 kg and comprises a base having a lower side with at least three spaced apart lower supports that are adapted for axially supporting the structure on one or more upper supports of another constructional structure of the platform.
  • Such supports are typically are adapted for, together, substantially completely supporting the weight of the constructional feature on the another constructional feature that has already been installed as part of the offshore platform.
  • the constructional structure may optionally comprise a number of modules that are supported on the base.
  • South-Korean patent application KR 20170048737 describes a method for installation of a top-side module on the top side of an offshore structure, using a marine crane that is provided on an overhead barge.
  • the known top-side module installation method comprises: a step of installing each column having a hollow interior to allow internal lifting tool (ILT) equipment to be inserted into opposing points along the periphery of a topside module to achieve convenient installation of the top side module using the ILT equipment; a step of inserting suspended ILT equipment into each column and then fixing the ILT equipment with the column; a step of lifting the topside module using the marine crane after fixing the ILT equipment with the column to be transferred to the top side of a marine structure and then, setting the correct position of the top side module; and a step of fixing the top side module in such a manner as to be placed on the top side after setting the right position of the top side module on the top side of the offshore structure.
  • the columns are typically fixed to the module while on-shore, and provide reinforced points of attachment that
  • a drawback is that the installation of the columns along opposing points along the periphery of the topside module requires significant amounts of reinforcements to be added to the topside modules.
  • Chinese patent application CN 101468774A describes a hoisting device for assisting in lifting a wind turbine.
  • the hoisting device comprises a holding part and two hanging parts that are fixedly attached at opposite sides of the holding part by means of diagonal bars, and the upper end of each hanging part is provided with lifting lugs into which lifting cables can be inserted.
  • the holding part is further provided with a hydraulic locking device for controlling the opening and closing of the holding part so that the holding part can be clamped around a upper portion of the wind turbine column.
  • the hoisting structure can thus engage an upper part of a column of the wind turbine, for substantially preventing lateral movement of the wind turbine as well as lifting a portion of the weight of the wind turbine.
  • further cables are attached to further lifting lugs that are provided at an upper surface of a base of the wind turbine.
  • the hoisting device is connected to an upper portion of the wind turbine column, and the further cables are connected to the lugs at the upper surface of the turbine's base, the turbine can be lifted in a substantially upright orientation without toppling over.
  • a module is known that can be installed on or removed from a support structure that is erected in a body of water. At an upwardly facing side the module is provided with lifting lugs to which lifting cables can be attached.
  • a drawback of the prior art module and of the prior art hoisting device is that typically significant amounts of reinforcements have to be provided near the locations of the lifting lugs on the object that is to be lifted.
  • the present invention provides a method for lifting a constructional structure of an offshore platform, wherein the constructional structure has a weight of at least 100000 kg, preferably at least 250000 kg, and comprises a base having a lower side with at least three spaced apart lower supports that are adapted for axially supporting the structure on one or more upper supports of another constructional structure of the platform, the base further comprising an upper side which faces away from the lower side, wherein the method comprises the steps of: connecting hoisting wires to or near the lower supports and below the center of mass of the constructional structure, in such a manner that when an axially directed lifting force is applied on the hoisting wires this axially directed force is substantially transferred via the lower supports to the rest of the base, and in such a manner that, while the axially directed lifting force is applied on the wires, the hoisting wires remain spaced apart from distal lower ends of the lower supports; and while the constructional structure is in an substantially upright orientation, lifting the constructional structure by applying an axial lifting force on each
  • the hoisting wires are connected to or near the lower supports, and preferably at the lower side of the base.
  • the lower supports which have as their main function to axially support the constructional structure on top of the another constructional structure, to be used to bear most of the weight of the structure as it is lifted using the cables.
  • the axially directed force for supporting the constructional structure may be substantially transferred via the lower supports to the rest of the base, rather than via the base to the lower supports.
  • the axially directed lifting force exerted on the hoisting wires is substantially completely transferred via the lower supports to the rest of the base, e.g. preferably at least 90% of the total axially directed lifting force exerted on the wires is transferred via the lower supports to the rest of the base.
  • the number of further reinforcement structures for attachment of hoisting wires at points well above the constructional structure center of mass can thus be reduced and may in some cases be zero. This also results in a decrease in amount of material that is used for reinforcement structures which have as their main function to allowing the structure to be lifted. Moreover, no or less time is needed to install reinforcements on the structural construction whose main purpose is to allow lifting thereof, the lifting method may provide more time efficient manner for attaching hoisting cables to a constructional structure. It will be clear that during lifting of a first constructional structure and/or when such a first constructional structure is supported on top of a second, other constructional structure, the lower side of the base of the first constructional structure faces downwards.
  • the method of the invention is particularly suitable for lifting a constructional structure which has already been placed with its lower supports on upper supports of another constructional structure, as it requires no or only a few reinforcement structures to be installed on the upper side of the base prior to lifting to ensure structural integrity of the constructional structure during lifting.
  • the method may thus be used for lifting the constructional structure of the offshore platform vertically upwards from said platform, e.g. when dismantling the platform.
  • the lower supports are preferably formed as columns which extend on the lower side of the base. At the points where the columns are to be supported on the upper supports, the columns are preferably oriented with their principal axes in the vertical direction.
  • the hoisting wires remain substantially parallel to each other during lifting to reduce the risk of sharp angled contact between those portions of the wires which extend above the supports and the structure itself, which would cause the wires the wear and/or damage to the constructional structure. Additionally, the as the wires remain substantially parallel during lifting, the force exerted thereby on the lowers supports will be substantially vertically directed, i.e. parallel to the direction in which the lower supports are typically strongest.
  • the hoisting wires remain spaced apart from the distal lower ends of the lower supports, so that structure can be placed with its lower supports onto the another constructional structure, without being placed on top of the hoisting wires.
  • the distal lower ends of the lower supports are preferably spaced vertically apart from the lower side of the base by a distance of at least 0,5 meter.
  • the constructional structure may for example be a topside with a number of support columns at its lower side which form the lower supports, and the another constructional feature may then be a jacket having an equal number of upper supports on its upper side for axially supporting the lower supports thereon.
  • the hoisting wires will be attached at or near the support columns at the lower side of the base of the topside; as these columns are sufficiently strong to support the weight of the topside they provide excellent points of attachment for the hoisting wires.
  • the hoisting cables are preferably connected to the lower supports in such a manner that, when they are disconnected from the lower supports the hoisting wires can moved away from the constructional feature while the hoisting wires remain substantially parallel to each other.
  • each of the wires deviates no more than 5 degrees from the vertical, and more preferably no more than 3 degrees from the vertical, most preferably no more than 1 ,5 degrees from the vertical.
  • each of the wires remains substantially uncoupled from the structure, except at the ends of the hoisting wires.
  • one end of the hoisting wire is connected at or near the lower supports and the other end is connected to a lifting beam, a lifting frame or a hook of a crane.
  • the wires may thus extend from the locations where the hoisting wires are connected at or near the lower supports, to a lifting beam, a lifting frame or a hook of a crane, in a straight line and without contacting any structure that is coupled, permanently or temporarily, to the constructional structure. Damage to the wires due to lateral contact of the wires with for instance the constructional structure or an element, such as hoisting a clamp or the like, is thus prevented.
  • those portions of the wires which extend above the supports, in particular at the upper side of the base, remain spaced apart from the constructional structure and/or from any element that is in direct contact with the constructional feature.
  • the wires are connected to or near the lower supports at a location below a horizontal plane through the lower side of the base. During lifting, the parallel wires thus extend through the horizontal plane, substantially vertically along the lower supports.
  • One or more wires may be connected to a lower support for instance via an internal lifting tool that clamps against an inner surface of the lower support at a position below the horizontal plane, an external lifting tool that is clamped around the lower support at a position below the horizontal plane, a padeye or trunnion that is welded to the lower support at a position below the horizontal plane, and the like.
  • the sum of axial lifting forces exerted on the hoisting wires is at least 70%, preferably at least 90% of the axial force required for vertically lifting the constructional structure.
  • the greater portion of the weight of the constructional structure is thus borne by the lower supports.
  • the upper supports of the another constructional structure extend above the water surface, wherein the another constructional structure has a lower portion that extends below the water surface.
  • the constructional structure has a center of mass, and, when the structure is lifted while in the substantially upright orientation, the center of mass is arranged at a level above each of the lower supports.
  • a constructional structure of an offshore platform is adapted such that its lower supports span an area within which the center-of-mass is arranged, and such that the lower supports are sufficiently spaced apart from each other that, when the constructional structure is supported on its lower supports, it stably maintains an upright orientation.
  • each of lower supports is spaced apart from the other lower supports by a distance of at least 10 meters.
  • At least two of said hoisting wires are connected to a substantially rigid lifting beam, wherein said at least two said hoisting wires are connected to the lifting beam at points substantially corresponding to the points where said hoisting wires are connected to or near the lower supports. For instance, if the center point of a first lower support is spaced apart by a predetermined distance from the center point of a second lower support, then the distance between wires connecting the rigid lifting beam and the respective first and second lower support will be substantially the same, allowing the wires to run substantially vertically from the points at or near lower supports to the lifting beam during lifting.
  • the points of connection of the hoisting wires with the lifting beam will generally correspond to the center axes of the lower supports in which the lifting tools are inserted. If the hoisting wire is attached to an external surface of a lower support, e.g. via a padeye or trunnion that is welded to the external surface, or via an external clamping tool that is clamped around the external surface, then the points of connection of the hoisting wires with the lifting beam will be offset with respect to the center axes. During lifting the hoisting wires are preferably substantially fixedly connected at said points of the lifting beam.
  • each hoisting wire has a length substantially equal to the vertical distance between the point where the wire is connected to the lifting beam and the point at or near which the wire is connected to its corresponding lower support.
  • at least three of said hoisting wires are connected to a substantially rigid lifting frame, wherein said at least three hoisting wires are connected to the lifting frame at points substantially corresponding to two or more of the lower supports.
  • the hoisting wires are preferably substantially fixedly connected at said points of the lifting frame. In this manner it is ensured that at least the wires connected to the lifting frame are substantially parallel to each other during lifting of the structure.
  • each hoisting wire is connected to a same lifting frame, with the lifting frame, when seen in projection onto a horizontal plane during lifting, spanning all of the at least three lower supports. More preferably, each hoisting wire has a length substantially equal to the vertical distance between the point where the wire is connected to the lifting frame and the point at or near which the wire is connected to its corresponding lower support.
  • the hoisting wires are connected to or near the lower supports in such a manner that the hoisting wires are spaced apart from the base, and in such a manner that, when seen in projection onto a horizontal plane, each of the hoisting wires is connected to or near one of the lower supports within a distance of 3 meters from an outer periphery of said lower support.
  • a hoisting wire may be connected to a trunnion or padeye or other reinforcement structure that has been attached to the lower support, wherein the other reinforcement structure is spaced apart from the base.
  • support extensions are attached to one or more of the lower supports, e.g. by welding, wherein each of the support extensions extends from its corresponding lower support, at least partially through the base, to an upper side of the support, and wherein one of the hoisting wires connected to the support extension.
  • the hoisting wire can be connected to the support extension in the manner as described earlier herein, e.g. using an internal lifting tool, an external lifting tool, or by connecting the hoisting wire to a padeye or trunnion that has been provided on the support extension.
  • Each support extension is preferably attached in such a manner to the lower support that if a lifting force is exerted on the support extension, most of this lifting force is transferred via the support extension to the lower support and subsequently to the rest of the base.
  • the one or more cranes are arranged on one or more vessels, such as one or more barges, which float on the water.
  • all of the hoisting wires are attached, via a single lifting frame, to a single crane.
  • the hoisting wires from separate cranes can be connected to the constructional structure, and each crane can be controlled such that the orientation of the constructional structure remains substantially upright during lifting. This allows very heavy constructional features to be lifted, even if the cranes on the separate vessels move somewhat differently from each other due to waves.
  • one or more of the one or more cranes is arranged on a jack-up vessel, wherein during lifting the jack-up vessel is substantially rigidly supported on the sea floor; and/or one or more of the one or more cranes is arranged on a platform that is fixed to and substantially rigidly supported by the sea floor.
  • the method comprises subsequent steps of: positioning the lifted constructional structure to a position in which the lower supports are substantially axially aligned with the one or more upper supports of the another constructional structure; and lowering the constructional structure until the lower supports are substantially completely supported on the one or more upper supports of the another constructional structure.
  • the constructional structure is first lifted and subsequently lowered with its lower supports onto the upper supports of the another structure. In this manner, the constructional module can be efficiently mounted to form part of the offshore platform under construction.
  • the parallel portions of the wires are arranged within 5 meters from the peripheral edge of the base, and preferably completely within said peripheral edge. Wear and/or shifting of the wires due to contact with the peripheral edge of the base is thus avoided.
  • the parallel portions of the lie within the peripheral edge of the base at a distance of at least 5 meters from the peripheral edge.
  • the area spanned by the lower supports is smaller than or equal to the area spanned by the base in said projection. This is typically the case when the constructional structure is a topside.
  • the area spanned by the lower supports is three fourth or less of the area spanned by the base.
  • each of the lower supports is spaced apart from the peripheral edge of the base by a distance greater than or equal to 4 times a length of said lower support along its principal axis in said projection. For instance, if a lower support has a cylindrical shape with an outer radius of 3,5 meters, then the closest distance of said lower support to the peripheral edge is at least 14 meters.
  • one or more of the wires are directly connected to the lower support surfaces.
  • a hoisting wires can be tied in a knot around the outer surface of its corresponding lower support, or the ends of the wire may be provided with a sling that is arranged around the lower support.
  • the direct connection is achieved by tying said one or more of the wires around the lower support surface on a lower side of the base.
  • the one or more hoisting are connected to the lowers supports such that, during lifting, the wires extend from the lower side of the base, through openings in the base towards the upper side of the base.
  • the constructional module that is to be lifted using the method is a topside or module that is to be arranged on the topside
  • the base of the constructional structure provided with openings which extend from the upper side of the base and debauch on the lower side of the base within the lower supports and/or substantially adjacent to an outer surface of the lower supports.
  • the wire when an internal lifting tool is attached at the end of a wire, then during lifting, the wire may extend through an opening that debauches on the lower side of the base within a corresponding lower support so that the wire may partially extend within the lower support.
  • the opening debauches on the lower side of the base substantially adjacent, e.g. within 5 meters, preferably within 3 meters, of the connection between the lower support to the lower side of the base, then the wire can be attached to an outer surface of the lower support, e.g. via an external lifting tool, by attaching the wire to a padeye or trunnion that is provided on the outer surface of the lower support, or by tying the wire around the outer surface of the lower support.
  • one or more of said lower supports comprises a leg having a substantially cylindrical or conical leg inner surface, wherein one or more of said wires is provided at an end thereof with an internal lifting tool adapted for engaging the leg’s inner surface.
  • one or more of said lower supports comprises a leg having a substantially cylindrical leg outer surface around which an external lifting tool is attached, wherein one or more of said wires is attached to said external lifting tool.
  • one or more of said lower supports is provided with a padeye or or trunnion to which one or more of the wires is attached.
  • the method further comprises, prior to lifting of the constructional structure, welding a reinforcement structure to the lower support, wherein the reinforcement structure is provided with a padeye or trunnion.
  • the constructional structure comprises or is a topside, wherein the one or more lower supports are formed by legs of the topside, and wherein the another constructional structure is a jacket.
  • the constructional structure comprises or is a topside module, wherein the one or more lower supports are formed by formed by legs of the topside module, and wherein the another constructional structure is a topside.
  • topside modules are living quarters for personnel, a helideck module, and a processing module for processing hydrocarbons.
  • the constructional structure comprises or is a wind turbine having a base, a column which extends from the base, a nacelle at the top of the column and provided with a rotor, wherein the wind turbine further comprises at least three spaced apart legs provided at a lower side of the base and which form the lower supports.
  • the constructional structure comprises or is a jacket, wherein the one or more lower supports are formed by lower ends of legs of the jacket, and wherein the another constructional structure is a jacket foundation.
  • the jacket typically has a base that extends substantially horizontally between the jacket legs above the lower ends of the legs.
  • Figs. 1 A, 2A and 3A respectively illustrate how a constructional structure in the form of a top side is lifted according to the method of the invention
  • Figs. 1 B, 2B and 3B respectively show bottom views from horizontal planes indicated by lines l-B, ll-B and lll-B of Figs. 1A, 2A and 3A;
  • Fig. 4 illustrates the method of the invention in which a constructional structure in the form of a top side is lifted using cranes on two separate vessels;
  • Figs. 5A, 5B and 5C respectively illustrate different manners in which the hoisting wires can be connected to a constructional structure in accordance with the method of the invention.
  • Figs. 1 A and 1 B respectively show a schematical side view and a view along direction l-B of Fig. 1 A, which illustrate an embodiment of the method according to the invention.
  • Shown are a barge 100, floating on the water and having a portion 101 below the water surface W and a portion 102 above the waterline.
  • a crane 1 10 is provided on the barge 100, having main wire 1 1 1 at the end of which a hook 1 12 is provided.
  • a further wire 1 13, which runs substantially vertically, is connected to a number of wires 1 14a, 1 14b which in turn are each attached to a corner of a lifting frame 120.
  • Hoisting wires 130a,130b,130c,130d are attached to the lifting frame 120 and extend substantially parallel to each other. At their lower ends, each of the hoisting wires is attached to an internal lifting tool, which clamps against an inner surface of lower supports 164a,164b,164c,164d of topside 160.
  • Constructional structures comprising the topside 160, jackets 170 and 180 form part of an offshore platform 105 together with foundation 190 that is fixed on the sea floor 106.
  • Each of the constructional structures 160,170,180 comprises a substantially horizontal base 161 ,171 ,181 below which lower supports extend in such a manner that distal lower portions of the lower supports are vertically spaced apart from the horizontal base 161 ,171 ,181 .
  • the foundation 190 comprises four upper supports, two of which, 195a, 195b, are shown in Fig. 1 A, and on top of which four lower supports of jacket 180 are axially supported. It will be understood that though the schematical side view of Fig.
  • FIG. 1A shows only two lower supports 164a, 164b, 174a, 174b, 184a, 184b of each of the constructional structures 160,170,180, each of these constructional structure is provided with four such lower supports.
  • the lower supports of each constructional structure are adapted for together substantially completely supporting the weight of the constructional structure.
  • the topside 160 comprises a base in the form of a lower deck 161 , and the lower supports 164 of the topside extend on a lower side of the base 161 .
  • the partially cut away detail of lower support 164a shows an internal lifting tool 131 a which clamps against an inner surface of the lower support and is connected to hoisting wire 130a.
  • the hoisting wire 130a thus extends from an end thereof that is attached to the lifting frame 120, through the base 161 of the topside 160 to an inner space of the lower support 164a, where the wire is connected to the lower support by means of the internal lifting tool 131 a at a position well below the center of mass C of the topside 160.
  • the hoisting wires 130a, 130b, 130c,130d extend in parallel from points below the center of mass C at or near the lower supports, to corresponding points of attachment with the lifting frame.
  • axial force exerted on the hoisting cables is transferred via the lower supports to the base 161 of the topside 160.
  • the combined lifting force that is exerted by the cables, via the lower supports to the base and rest of the topside, is sufficient to lift the topside. That is, the combined axially directed lifting force that is exerted, through the four lower supports, on the topside 160 during lifting will be substantially equal to the mass of the topside times the gravitational acceleration of about 9.80665 m/s 2 .
  • Fig. 1 B schematically shows a bottom view of the topside 160 and lifting frame 120 from the level of the plane indicated by line IB in Fig. 1A in which hollow lower supports 164a, 164b, 164c, 164d at a lower side 162 of the base 161 can be seen.
  • the lifting frame 120 would typically not be visible in the bottom view, it has been indicated using dotted lines to illustrate the points of attachment between the lifting frame 120 and the hoisting wires 130a,130b,130c,130d.
  • the hoisting wires extend through the lower supports along vertical axes indicated by reference numerals 133a,133b, 133c, 133d, and are connected to a corresponding internal lifting tool 131 a,131 b,131 c,131 d that clamps against an inner surface of its corresponding the hollow lower support.
  • the center of mass C is arranged within an area spanned by the lower supports, in order to provide stability when the topside is lifted in an upright orientation.
  • the area spanned by the lower supports 164a-164d is smaller than the area spanned by the bottom side 161 of the base 161 , stability during lifting is improved by spacing each of the lower supports a distance of at least 10 meters apart from the other lower supports.
  • the lower supports are thus also spaced apart from outer peripheral edge E of the base 160.
  • Figs. 2A and 2B illustrates another method for lifting such a topside 160, in which instead of an internal lifting tool an external lifting tool is used which clamps around an outer surface of the lower support 130a, as show in the detail of lower support 130a in Fig. 2A.
  • Fig. 2B schematically shows a bottom view of the topside along the plane indicated by line ll-B in Fig. 2A, again with the lifiting frame 120 shown in dotted lines.
  • the hook 1 12 here is attached directly to wires 1 14a, 1 14b which are connected to the lifting frame 120.
  • the hoisting wires 130a - 130d run, from lifting frame 120, parallel to each other at the exterior sides of the lower supports 130a, 130b to the corresponding external lifting tools.
  • the base is provided with openings 167a-167d which extend through the base 161 , from an upper side 163 thereof to a lower side 162 of the base.
  • each openings is arranged substantially adjacent to a portion of the outer surface of its corresponding lower support, in the present example the center of the opening is within 3 meters of the outer surface of the corresponding lower support.
  • the four hoisiting wires can thus extend substantially in parallel to each other from their points of attachment to the corresponding external lifting tools, and to their points of attachment to the lifting frame 120.
  • Figs. 3A and 3B illustrates another method for lifting a topside 160, in which instead of an internal or external lifting tool, padeyes are used for connecting the lower ends of the hoisting wires to the lower supports.
  • Fig. 3A schematically shows the topside 160 as it is being lifted as well as a detail of hoisting cable 130a that is connected by such at padeye to lower support 164a of the topside 160.
  • Fig. 3B schematically shows a bottom view of the topside 160, with the lifting frame 120 again indicated in dotted lines.
  • the hoisting wires 130a-130d run through openings 167a-167d in the base, wherein the openings are substantially adjacent to their corresponding lower supports.
  • padeyes trunnions or the like may be attached to the outer surfaces of the lower supports, for connecting the hoisting wires to lower supports.
  • Fig. 4 schematically shows the topside 160 as it is lifted using hoisting wires that are connected to two different cranes 1 10, 210 that are provided on two different vessels 100,200.
  • Each crane is connected, via a main wire cable 1 1 1 ,21 1 , hook 1 12,212 and lifting beam 120’, 220, to hoisting wires.
  • crane 210 is connected, via lifting beam 220 to two separate hoisting wires indicated schematically by reference numerals 230a, 230b
  • crane 1 10 is connected, via lifting beam 120’ to two separate hoisting wires indicated schematically by reference numerals 130a, 130b.
  • the hoisting wires are connected to corresponding lower supports of the top side at a position well below the topside’s center of mass C. As the lower supports are already provided for axially supporting the weight of the topside thereon, the lower supports are sufficiently strong to withstand the forces exerted thereon during lifting.
  • Figs. 5A,5B and 5C schematically illustrate different positions where the hoisting wires can be attached to a constructional structure 360 according to the method of the invention.
  • the constructional structure is provided with a base 361 , having a lower side 362 and an upper side 363.
  • the base is arranged below the constructional structure’s center of mass C, and is provided with lower supports 364a-364d which extend at and from the lower side of the base 361 .
  • four hoisting wires 330a-330d run parallel to each other from two separate lifting beams 120’ and to below the lower side 362 of the base where they are connected to the lower supports.
  • the connections are made via internal lifting tools that are arranged within the lower supports.
  • the hoisting wires 330a-330d are attached to the constructional structure 360 by means of padeyes that are welded onto upper side of the base at positions directly above the lower supports 364a-364d lower where the constructional feature is axially supported by the lower supports. At corresponding positions on the lower side of the base the lower supports are fixed to the base, e.g. by welding.
  • the hoisting wires 330a-330d are connected to the padeyes at positions well below the center of mass C.
  • support extensions 374a-374d have been welded onto the lower supports 364a- 364d, wherein internal lifting tools (indicated schematically) have been arranged in the support extensions at a position well below the center of mass C but above the lower side 362 of the base.
  • internal lifting tools indicated schematically
  • support extensions can be used that have a length that smaller than, e.g. half or less, the height of the constructional structure 360.
  • the hoisting wires run parallel to each other and are connected to or near the lower supports at positions well below the center of mass.
  • the lower end point of each hoisting wire thus lies well below the constructional structure’s center of mass C and is attached to a lower support which provided a readily available strong point by which the structure may be lifted.
  • a lifting force is exerted on the cables, a substantial portion of this force is transmitted via the padeyes to the lower supports and subsequently to the base.

Abstract

Method for lifting a constructional structure of an offshore platform, wherein the constructional structure has a weight of at least 100000 kg and a base having an upper side an a lower side with at least three spaced apart lower supports adapted for axially supporting the structure on one or more upper supports of another constructional structure of the platform, the method comprising: connecting hoisting wires to or near the lower supports and below the center of mass of the constructional structure, in such a manner that when an axially directed lifting force is applied on the wires this axially directed force is substantially transferred via the lower supports to the rest of the base and in such a manner that, while the axially directed lifting force is applied on the wires, the hoisting wires remain spaced apart from distal lower ends of the lower supports; and while the constructional structure is in an substantially upright orientation, lifting the constructional structure by using one or more cranes to apply an axially directed lifting force on each of the wires in such a manner that the wires extend substantially parallel to each other.

Description

Method for installation of an offshore structure using one or more cranes Field of the invention
The present invention relates to a method for lifting a constructional structure of an offshore platform using one or more cranes at an offshore location. A constructional structure is herein defined as a structure that is part of, or is to form part of, the offshore platform, has a weight of at least 100000 kg and comprises a base having a lower side with at least three spaced apart lower supports that are adapted for axially supporting the structure on one or more upper supports of another constructional structure of the platform. Such supports are typically are adapted for, together, substantially completely supporting the weight of the constructional feature on the another constructional feature that has already been installed as part of the offshore platform. The constructional structure may optionally comprise a number of modules that are supported on the base.
Background art
When lifting heavy constructional structures for an offshore platform, it is common practice to provide the constructional structure that is to be lifted with some form of reinforcement to which wires can be attached for lifting the constructional structure. For instance, it is known to provide a topside or a topside module, e.g. a living quarters module, for an offshore platform with reinforcement structures at or near its upper side, so that hoisting wires can be connected to the reinforcement structures.
South-Korean patent application KR 20170048737 describes a method for installation of a top-side module on the top side of an offshore structure, using a marine crane that is provided on an overhead barge. The known top-side module installation method comprises: a step of installing each column having a hollow interior to allow internal lifting tool (ILT) equipment to be inserted into opposing points along the periphery of a topside module to achieve convenient installation of the top side module using the ILT equipment; a step of inserting suspended ILT equipment into each column and then fixing the ILT equipment with the column; a step of lifting the topside module using the marine crane after fixing the ILT equipment with the column to be transferred to the top side of a marine structure and then, setting the correct position of the top side module; and a step of fixing the top side module in such a manner as to be placed on the top side after setting the right position of the top side module on the top side of the offshore structure. The columns are typically fixed to the module while on-shore, and provide reinforced points of attachment that may be engaged by the ILT equipment without causing substantial damage to the module.
Though the known method may shorten installation time for various topside modules, a drawback is that the installation of the columns along opposing points along the periphery of the topside module requires significant amounts of reinforcements to be added to the topside modules.
Chinese patent application CN 101468774A describes a hoisting device for assisting in lifting a wind turbine. The hoisting device comprises a holding part and two hanging parts that are fixedly attached at opposite sides of the holding part by means of diagonal bars, and the upper end of each hanging part is provided with lifting lugs into which lifting cables can be inserted. The holding part is further provided with a hydraulic locking device for controlling the opening and closing of the holding part so that the holding part can be clamped around a upper portion of the wind turbine column. The hoisting structure can thus engage an upper part of a column of the wind turbine, for substantially preventing lateral movement of the wind turbine as well as lifting a portion of the weight of the wind turbine. Additionally, for lifting the wind turbine, further cables are attached to further lifting lugs that are provided at an upper surface of a base of the wind turbine. As the hoisting device is connected to an upper portion of the wind turbine column, and the further cables are connected to the lugs at the upper surface of the turbine's base, the turbine can be lifted in a substantially upright orientation without toppling over.
From US 4,744,697 a module is known that can be installed on or removed from a support structure that is erected in a body of water. At an upwardly facing side the module is provided with lifting lugs to which lifting cables can be attached.
A drawback of the prior art module and of the prior art hoisting device is that typically significant amounts of reinforcements have to be provided near the locations of the lifting lugs on the object that is to be lifted.
It is an object of the present invention to provide a method which at least partially overcomes this drawback.
Summary of the invention
To this end, the present invention provides a method for lifting a constructional structure of an offshore platform, wherein the constructional structure has a weight of at least 100000 kg, preferably at least 250000 kg, and comprises a base having a lower side with at least three spaced apart lower supports that are adapted for axially supporting the structure on one or more upper supports of another constructional structure of the platform, the base further comprising an upper side which faces away from the lower side, wherein the method comprises the steps of: connecting hoisting wires to or near the lower supports and below the center of mass of the constructional structure, in such a manner that when an axially directed lifting force is applied on the hoisting wires this axially directed force is substantially transferred via the lower supports to the rest of the base, and in such a manner that, while the axially directed lifting force is applied on the wires, the hoisting wires remain spaced apart from distal lower ends of the lower supports; and while the constructional structure is in an substantially upright orientation, lifting the constructional structure by applying an axial lifting force on each of the wires in such a manner that the wires extend substantially parallel to each other. For such heavy structures it is typically not feasible to loop hoisting wires around the entire lower side of the structure as the force exerted on the loop may cause damage to the wires and/or the structure. Moreover, a lower portion of the loop may become clamped between a lower side of the structure and an upper side of another structure onto which the first structure is to be placed. Instead in the prior art, when very heavy structures are to be lifted, it has been common practise to attach hoisting wires with their distal ends at or near the top of the structure, i.e. above the constructional structure’s center of mass, so that the structure may easily be kept in an upright orientation during lifting and subsequent placement of the structure on another structure. This typically requires attaching significant reinforcements to the structure at positions above a horizontal plane through the structure’s center of mass.
In contrast, according to the present invention, the hoisting wires are connected to or near the lower supports, and preferably at the lower side of the base. This allows the lower supports, which have as their main function to axially support the constructional structure on top of the another constructional structure, to be used to bear most of the weight of the structure as it is lifted using the cables. In this manner, during lifting, as well as when the constructional structure is been placed with its lower supports on one or more upper supports of the another structural, the axially directed force for supporting the constructional structure may be substantially transferred via the lower supports to the rest of the base, rather than via the base to the lower supports. Preferably, during lifting, the axially directed lifting force exerted on the hoisting wires is substantially completely transferred via the lower supports to the rest of the base, e.g. preferably at least 90% of the total axially directed lifting force exerted on the wires is transferred via the lower supports to the rest of the base.
The number of further reinforcement structures for attachment of hoisting wires at points well above the constructional structure center of mass can thus be reduced and may in some cases be zero. This also results in a decrease in amount of material that is used for reinforcement structures which have as their main function to allowing the structure to be lifted. Moreover, no or less time is needed to install reinforcements on the structural construction whose main purpose is to allow lifting thereof, the lifting method may provide more time efficient manner for attaching hoisting cables to a constructional structure. It will be clear that during lifting of a first constructional structure and/or when such a first constructional structure is supported on top of a second, other constructional structure, the lower side of the base of the first constructional structure faces downwards.
The method of the invention is particularly suitable for lifting a constructional structure which has already been placed with its lower supports on upper supports of another constructional structure, as it requires no or only a few reinforcement structures to be installed on the upper side of the base prior to lifting to ensure structural integrity of the constructional structure during lifting. The method may thus be used for lifting the constructional structure of the offshore platform vertically upwards from said platform, e.g. when dismantling the platform.
The lower supports are preferably formed as columns which extend on the lower side of the base. At the points where the columns are to be supported on the upper supports, the columns are preferably oriented with their principal axes in the vertical direction.
The hoisting wires remain substantially parallel to each other during lifting to reduce the risk of sharp angled contact between those portions of the wires which extend above the supports and the structure itself, which would cause the wires the wear and/or damage to the constructional structure. Additionally, the as the wires remain substantially parallel during lifting, the force exerted thereby on the lowers supports will be substantially vertically directed, i.e. parallel to the direction in which the lower supports are typically strongest.
As, during lifting, the hoisting wires remain spaced apart from the distal lower ends of the lower supports, so that structure can be placed with its lower supports onto the another constructional structure, without being placed on top of the hoisting wires. The distal lower ends of the lower supports are preferably spaced vertically apart from the lower side of the base by a distance of at least 0,5 meter.
The constructional structure may for example be a topside with a number of support columns at its lower side which form the lower supports, and the another constructional feature may then be a jacket having an equal number of upper supports on its upper side for axially supporting the lower supports thereon. In such a case the hoisting wires will be attached at or near the support columns at the lower side of the base of the topside; as these columns are sufficiently strong to support the weight of the topside they provide excellent points of attachment for the hoisting wires.
The hoisting cables are preferably connected to the lower supports in such a manner that, when they are disconnected from the lower supports the hoisting wires can moved away from the constructional feature while the hoisting wires remain substantially parallel to each other.
In an embodiment, during lifting, each of the wires deviates no more than 5 degrees from the vertical, and more preferably no more than 3 degrees from the vertical, most preferably no more than 1 ,5 degrees from the vertical.
In an embodiment, during lifting, each of the wires remains substantially uncoupled from the structure, except at the ends of the hoisting wires. Typically, one end of the hoisting wire is connected at or near the lower supports and the other end is connected to a lifting beam, a lifting frame or a hook of a crane. The wires may thus extend from the locations where the hoisting wires are connected at or near the lower supports, to a lifting beam, a lifting frame or a hook of a crane, in a straight line and without contacting any structure that is coupled, permanently or temporarily, to the constructional structure. Damage to the wires due to lateral contact of the wires with for instance the constructional structure or an element, such as hoisting a clamp or the like, is thus prevented.
In an embodiment, during lifting of the constructional structure, those portions of the wires which extend above the supports, in particular at the upper side of the base, remain spaced apart from the constructional structure and/or from any element that is in direct contact with the constructional feature.
In an embodiment the wires are connected to or near the lower supports at a location below a horizontal plane through the lower side of the base. During lifting, the parallel wires thus extend through the horizontal plane, substantially vertically along the lower supports. One or more wires may be connected to a lower support for instance via an internal lifting tool that clamps against an inner surface of the lower support at a position below the horizontal plane, an external lifting tool that is clamped around the lower support at a position below the horizontal plane, a padeye or trunnion that is welded to the lower support at a position below the horizontal plane, and the like.
In an embodiment during said lifting, the sum of axial lifting forces exerted on the hoisting wires is at least 70%, preferably at least 90% of the axial force required for vertically lifting the constructional structure. During lifting, the greater portion of the weight of the constructional structure is thus borne by the lower supports.
In an embodiment the upper supports of the another constructional structure extend above the water surface, wherein the another constructional structure has a lower portion that extends below the water surface.
In an embodiment the constructional structure has a center of mass, and, when the structure is lifted while in the substantially upright orientation, the center of mass is arranged at a level above each of the lower supports. Typically, when mounted and seen in projection onto a horizontal plane, a constructional structure of an offshore platform is adapted such that its lower supports span an area within which the center-of-mass is arranged, and such that the lower supports are sufficiently spaced apart from each other that, when the constructional structure is supported on its lower supports, it stably maintains an upright orientation. By lifting such a constructional structure from its lower supports, it can easily be maintained in a substantially upright orientation during lifting.
In an embodiment, each of lower supports is spaced apart from the other lower supports by a distance of at least 10 meters.
In an embodiment at least two of said hoisting wires are connected to a substantially rigid lifting beam, wherein said at least two said hoisting wires are connected to the lifting beam at points substantially corresponding to the points where said hoisting wires are connected to or near the lower supports. For instance, if the center point of a first lower support is spaced apart by a predetermined distance from the center point of a second lower support, then the distance between wires connecting the rigid lifting beam and the respective first and second lower support will be substantially the same, allowing the wires to run substantially vertically from the points at or near lower supports to the lifting beam during lifting. When internal lifting tools are used, the points of connection of the hoisting wires with the lifting beam will generally correspond to the center axes of the lower supports in which the lifting tools are inserted. If the hoisting wire is attached to an external surface of a lower support, e.g. via a padeye or trunnion that is welded to the external surface, or via an external clamping tool that is clamped around the external surface, then the points of connection of the hoisting wires with the lifting beam will be offset with respect to the center axes. During lifting the hoisting wires are preferably substantially fixedly connected at said points of the lifting beam. More preferably, each hoisting wire has a length substantially equal to the vertical distance between the point where the wire is connected to the lifting beam and the point at or near which the wire is connected to its corresponding lower support. In an embodiment at least three of said hoisting wires are connected to a substantially rigid lifting frame, wherein said at least three hoisting wires are connected to the lifting frame at points substantially corresponding to two or more of the lower supports. During lifting the hoisting wires are preferably substantially fixedly connected at said points of the lifting frame. In this manner it is ensured that at least the wires connected to the lifting frame are substantially parallel to each other during lifting of the structure. Preferably, all hoisting wires are connected to a same lifting frame, with the lifting frame, when seen in projection onto a horizontal plane during lifting, spanning all of the at least three lower supports. More preferably, each hoisting wire has a length substantially equal to the vertical distance between the point where the wire is connected to the lifting frame and the point at or near which the wire is connected to its corresponding lower support.
In an embodiment the hoisting wires are connected to or near the lower supports in such a manner that the hoisting wires are spaced apart from the base, and in such a manner that, when seen in projection onto a horizontal plane, each of the hoisting wires is connected to or near one of the lower supports within a distance of 3 meters from an outer periphery of said lower support. For instance a hoisting wire may be connected to a trunnion or padeye or other reinforcement structure that has been attached to the lower support, wherein the other reinforcement structure is spaced apart from the base.
In an embodiment, support extensions are attached to one or more of the lower supports, e.g. by welding, wherein each of the support extensions extends from its corresponding lower support, at least partially through the base, to an upper side of the support, and wherein one of the hoisting wires connected to the support extension. The hoisting wire can be connected to the support extension in the manner as described earlier herein, e.g. using an internal lifting tool, an external lifting tool, or by connecting the hoisting wire to a padeye or trunnion that has been provided on the support extension. Each support extension is preferably attached in such a manner to the lower support that if a lifting force is exerted on the support extension, most of this lifting force is transferred via the support extension to the lower support and subsequently to the rest of the base.
In an embodiment the one or more cranes are arranged on one or more vessels, such as one or more barges, which float on the water. Preferably, all of the hoisting wires are attached, via a single lifting frame, to a single crane. However, when two or more cranes on separate vessels are used, with at least one crane on each vessel, the hoisting wires from separate cranes can be connected to the constructional structure, and each crane can be controlled such that the orientation of the constructional structure remains substantially upright during lifting. This allows very heavy constructional features to be lifted, even if the cranes on the separate vessels move somewhat differently from each other due to waves.
In an embodiment, one or more of the one or more cranes is arranged on a jack-up vessel, wherein during lifting the jack-up vessel is substantially rigidly supported on the sea floor; and/or one or more of the one or more cranes is arranged on a platform that is fixed to and substantially rigidly supported by the sea floor. In an embodiment the method comprises subsequent steps of: positioning the lifted constructional structure to a position in which the lower supports are substantially axially aligned with the one or more upper supports of the another constructional structure; and lowering the constructional structure until the lower supports are substantially completely supported on the one or more upper supports of the another constructional structure. Thus, the constructional structure is first lifted and subsequently lowered with its lower supports onto the upper supports of the another structure. In this manner, the constructional module can be efficiently mounted to form part of the offshore platform under construction.
In an embodiment when the constructional structure is being lifted in the upright orientation, and when viewed in projection onto a horizontal plane, the parallel portions of the wires are arranged within 5 meters from the peripheral edge of the base, and preferably completely within said peripheral edge. Wear and/or shifting of the wires due to contact with the peripheral edge of the base is thus avoided. Preferably, when viewed in said projection, the parallel portions of the lie within the peripheral edge of the base at a distance of at least 5 meters from the peripheral edge.
In an embodiment when the constructional structure is being lifted in the upright orientation, and when viewed in projection onto a horizontal plane, the area spanned by the lower supports is smaller than or equal to the area spanned by the base in said projection. This is typically the case when the constructional structure is a topside. Preferably, the area spanned by the lower supports is three fourth or less of the area spanned by the base.
In an embodiment when the constructional structure is being lifted in the upright orientation, and when viewed in projection onto a horizontal plane, each of the lower supports is spaced apart from the peripheral edge of the base by a distance greater than or equal to 4 times a length of said lower support along its principal axis in said projection. For instance, if a lower support has a cylindrical shape with an outer radius of 3,5 meters, then the closest distance of said lower support to the peripheral edge is at least 14 meters.
In an embodiment one or more of the wires are directly connected to the lower support surfaces. For instance, a hoisting wires can be tied in a knot around the outer surface of its corresponding lower support, or the ends of the wire may be provided with a sling that is arranged around the lower support.
In an embodiment the direct connection is achieved by tying said one or more of the wires around the lower support surface on a lower side of the base.
In an embodiment the one or more hoisting are connected to the lowers supports such that, during lifting, the wires extend from the lower side of the base, through openings in the base towards the upper side of the base. For instance, when the constructional module that is to be lifted using the method is a topside or module that is to be arranged on the topside, the base of the constructional structure provided with openings which extend from the upper side of the base and debauch on the lower side of the base within the lower supports and/or substantially adjacent to an outer surface of the lower supports. E.g., when an internal lifting tool is attached at the end of a wire, then during lifting, the wire may extend through an opening that debauches on the lower side of the base within a corresponding lower support so that the wire may partially extend within the lower support. Alternatively, then the opening debauches on the lower side of the base substantially adjacent, e.g. within 5 meters, preferably within 3 meters, of the connection between the lower support to the lower side of the base, then the wire can be attached to an outer surface of the lower support, e.g. via an external lifting tool, by attaching the wire to a padeye or trunnion that is provided on the outer surface of the lower support, or by tying the wire around the outer surface of the lower support.
In an embodiment, one or more of said lower supports comprises a leg having a substantially cylindrical or conical leg inner surface, wherein one or more of said wires is provided at an end thereof with an internal lifting tool adapted for engaging the leg’s inner surface.
In an embodiment one or more of said lower supports comprises a leg having a substantially cylindrical leg outer surface around which an external lifting tool is attached, wherein one or more of said wires is attached to said external lifting tool.
In an embodiment wherein one or more of said lower supports is provided with a padeye or or trunnion to which one or more of the wires is attached.
In an embodiment the method further comprises, prior to lifting of the constructional structure, welding a reinforcement structure to the lower support, wherein the reinforcement structure is provided with a padeye or trunnion.
In an embodiment the constructional structure comprises or is a topside, wherein the one or more lower supports are formed by legs of the topside, and wherein the another constructional structure is a jacket. I
In an embodiment the constructional structure comprises or is a topside module, wherein the one or more lower supports are formed by formed by legs of the topside module, and wherein the another constructional structure is a topside. Examples of topside modules are living quarters for personnel, a helideck module, and a processing module for processing hydrocarbons.
In an embodiment, the constructional structure comprises or is a wind turbine having a base, a column which extends from the base, a nacelle at the top of the column and provided with a rotor, wherein the wind turbine further comprises at least three spaced apart legs provided at a lower side of the base and which form the lower supports.
In an embodiment the constructional structure comprises or is a jacket, wherein the one or more lower supports are formed by lower ends of legs of the jacket, and wherein the another constructional structure is a jacket foundation. The jacket typically has a base that extends substantially horizontally between the jacket legs above the lower ends of the legs. Short description of drawings
The present invention will be discussed in more detail below, with reference to the attached drawings, in which same reference numerals refer to the same structures or elements, and in which:
Figs. 1 A, 2A and 3A respectively illustrate how a constructional structure in the form of a top side is lifted according to the method of the invention;
Figs. 1 B, 2B and 3B respectively show bottom views from horizontal planes indicated by lines l-B, ll-B and lll-B of Figs. 1A, 2A and 3A;
Fig. 4 illustrates the method of the invention in which a constructional structure in the form of a top side is lifted using cranes on two separate vessels; and
Figs. 5A, 5B and 5C respectively illustrate different manners in which the hoisting wires can be connected to a constructional structure in accordance with the method of the invention.
Description of embodiments
Figs. 1 A and 1 B respectively show a schematical side view and a view along direction l-B of Fig. 1 A, which illustrate an embodiment of the method according to the invention. Shown are a barge 100, floating on the water and having a portion 101 below the water surface W and a portion 102 above the waterline. A crane 1 10 is provided on the barge 100, having main wire 1 1 1 at the end of which a hook 1 12 is provided. A further wire 1 13, which runs substantially vertically, is connected to a number of wires 1 14a, 1 14b which in turn are each attached to a corner of a lifting frame 120. Hoisting wires 130a,130b,130c,130d are attached to the lifting frame 120 and extend substantially parallel to each other. At their lower ends, each of the hoisting wires is attached to an internal lifting tool, which clamps against an inner surface of lower supports 164a,164b,164c,164d of topside 160.
Constructional structures comprising the topside 160, jackets 170 and 180 form part of an offshore platform 105 together with foundation 190 that is fixed on the sea floor 106. Each of the constructional structures 160,170,180 comprises a substantially horizontal base 161 ,171 ,181 below which lower supports extend in such a manner that distal lower portions of the lower supports are vertically spaced apart from the horizontal base 161 ,171 ,181 . The foundation 190 comprises four upper supports, two of which, 195a, 195b, are shown in Fig. 1 A, and on top of which four lower supports of jacket 180 are axially supported. It will be understood that though the schematical side view of Fig. 1A shows only two lower supports 164a, 164b, 174a, 174b, 184a, 184b of each of the constructional structures 160,170,180, each of these constructional structure is provided with four such lower supports. The lower supports of each constructional structure are adapted for together substantially completely supporting the weight of the constructional structure. The topside 160 comprises a base in the form of a lower deck 161 , and the lower supports 164 of the topside extend on a lower side of the base 161 . The partially cut away detail of lower support 164a shows an internal lifting tool 131 a which clamps against an inner surface of the lower support and is connected to hoisting wire 130a. The hoisting wire 130a thus extends from an end thereof that is attached to the lifting frame 120, through the base 161 of the topside 160 to an inner space of the lower support 164a, where the wire is connected to the lower support by means of the internal lifting tool 131 a at a position well below the center of mass C of the topside 160. When an substantially vertically directed axial force Fa is exerted thereon, the hoisting wires 130a, 130b, 130c,130d extend in parallel from points below the center of mass C at or near the lower supports, to corresponding points of attachment with the lifting frame. Thus, during lifting, axial force exerted on the hoisting cables is transferred via the lower supports to the base 161 of the topside 160. The combined lifting force that is exerted by the cables, via the lower supports to the base and rest of the topside, is sufficient to lift the topside. That is, the combined axially directed lifting force that is exerted, through the four lower supports, on the topside 160 during lifting will be substantially equal to the mass of the topside times the gravitational acceleration of about 9.80665 m/s2.
Fig. 1 B schematically shows a bottom view of the topside 160 and lifting frame 120 from the level of the plane indicated by line IB in Fig. 1A in which hollow lower supports 164a, 164b, 164c, 164d at a lower side 162 of the base 161 can be seen. Though the lifting frame 120 would typically not be visible in the bottom view, it has been indicated using dotted lines to illustrate the points of attachment between the lifting frame 120 and the hoisting wires 130a,130b,130c,130d. The hoisting wires extend through the lower supports along vertical axes indicated by reference numerals 133a,133b, 133c, 133d, and are connected to a corresponding internal lifting tool 131 a,131 b,131 c,131 d that clamps against an inner surface of its corresponding the hollow lower support.
In the view of Fig. 1 B, the center of mass C is arranged within an area spanned by the lower supports, in order to provide stability when the topside is lifted in an upright orientation. Though in the bottom view of Fig. 1 B, the area spanned by the lower supports 164a-164d is smaller than the area spanned by the bottom side 161 of the base 161 , stability during lifting is improved by spacing each of the lower supports a distance of at least 10 meters apart from the other lower supports. The lower supports are thus also spaced apart from outer peripheral edge E of the base 160.
Figs. 2A and 2B illustrates another method for lifting such a topside 160, in which instead of an internal lifting tool an external lifting tool is used which clamps around an outer surface of the lower support 130a, as show in the detail of lower support 130a in Fig. 2A. Fig. 2B schematically shows a bottom view of the topside along the plane indicated by line ll-B in Fig. 2A, again with the lifiting frame 120 shown in dotted lines. The hook 1 12 here is attached directly to wires 1 14a, 1 14b which are connected to the lifting frame 120. The hoisting wires 130a - 130d run, from lifting frame 120, parallel to each other at the exterior sides of the lower supports 130a, 130b to the corresponding external lifting tools. In order to allow the hoisting wires to pass through the base 160, the base is provided with openings 167a-167d which extend through the base 161 , from an upper side 163 thereof to a lower side 162 of the base. In the view shown in Fig. 2B, each openings is arranged substantially adjacent to a portion of the outer surface of its corresponding lower support, in the present example the center of the opening is within 3 meters of the outer surface of the corresponding lower support. During lifting, the four hoisiting wires can thus extend substantially in parallel to each other from their points of attachment to the corresponding external lifting tools, and to their points of attachment to the lifting frame 120.
Figs. 3A and 3B illustrates another method for lifting a topside 160, in which instead of an internal or external lifting tool, padeyes are used for connecting the lower ends of the hoisting wires to the lower supports. Fig. 3A schematically shows the topside 160 as it is being lifted as well as a detail of hoisting cable 130a that is connected by such at padeye to lower support 164a of the topside 160. Fig. 3B schematically shows a bottom view of the topside 160, with the lifting frame 120 again indicated in dotted lines. As in the embodiment of Fig. 2A and 2B, the hoisting wires 130a-130d run through openings 167a-167d in the base, wherein the openings are substantially adjacent to their corresponding lower supports. Though not shown, instead of padeyes, trunnions or the like may be attached to the outer surfaces of the lower supports, for connecting the hoisting wires to lower supports.
Fig. 4 schematically shows the topside 160 as it is lifted using hoisting wires that are connected to two different cranes 1 10, 210 that are provided on two different vessels 100,200. Each crane is connected, via a main wire cable 1 1 1 ,21 1 , hook 1 12,212 and lifting beam 120’, 220, to hoisting wires. Thus, crane 210 is connected, via lifting beam 220 to two separate hoisting wires indicated schematically by reference numerals 230a, 230b, and crane 1 10 is connected, via lifting beam 120’ to two separate hoisting wires indicated schematically by reference numerals 130a, 130b. The hoisting wires are connected to corresponding lower supports of the top side at a position well below the topside’s center of mass C. As the lower supports are already provided for axially supporting the weight of the topside thereon, the lower supports are sufficiently strong to withstand the forces exerted thereon during lifting.
Figs. 5A,5B and 5C schematically illustrate different positions where the hoisting wires can be attached to a constructional structure 360 according to the method of the invention. The constructional structure is provided with a base 361 , having a lower side 362 and an upper side 363. The base is arranged below the constructional structure’s center of mass C, and is provided with lower supports 364a-364d which extend at and from the lower side of the base 361 . In Fig. 5A four hoisting wires 330a-330d run parallel to each other from two separate lifting beams 120’ and to below the lower side 362 of the base where they are connected to the lower supports. In Fig. 5A the connections are made via internal lifting tools that are arranged within the lower supports.
In Fig. 5B, the hoisting wires 330a-330d are attached to the constructional structure 360 by means of padeyes that are welded onto upper side of the base at positions directly above the lower supports 364a-364d lower where the constructional feature is axially supported by the lower supports. At corresponding positions on the lower side of the base the lower supports are fixed to the base, e.g. by welding. The hoisting wires 330a-330d are connected to the padeyes at positions well below the center of mass C. When a vertically directed lifting force is exerted on the parallel hoisting wires 330a-330d, a substantial portion of this force is transmitted via the padeys to the lower supports and subsequently to the rest of the base. In Fig. 5C, support extensions 374a-374d have been welded onto the lower supports 364a- 364d, wherein internal lifting tools (indicated schematically) have been arranged in the support extensions at a position well below the center of mass C but above the lower side 362 of the base. In this manner support extensions can be used that have a length that smaller than, e.g. half or less, the height of the constructional structure 360. When a vertically lifting force is exerted on the parallel hoisting wires, a substantial portion of this force is transmitted via the extensions 374a-374d to the lower supports and subsequently to the base 360.
In each of Figs. 5A,5B and 5C, the hoisting wires run parallel to each other and are connected to or near the lower supports at positions well below the center of mass. The lower end point of each hoisting wire thus lies well below the constructional structure’s center of mass C and is attached to a lower support which provided a readily available strong point by which the structure may be lifted. When a lifting force is exerted on the cables, a substantial portion of this force is transmitted via the padeyes to the lower supports and subsequently to the base.
The present invention has been described above with reference to a number of exemplary embodiments as shown in the drawings. Modifications and alternative implementations of some parts or elements are possible, and are included in the scope of protection as defined in the appended claims. In particular, though the examples illustrated in the figures show lifting of a constructional structure in the form of a topside, the skilled person will understand that the method can be used to lift constructional structures such as a jacket module as well.

Claims

Claims
1 . Method for lifting a constructional structure (160; 170; 180) of an offshore platform (1), wherein the constructional structure has a weight of at least 100000 kg and comprises a base (161 ; 171 ; 181) having a lower side (162) and an upper side (163), the constructional structure further comprising at least three spaced apart lower supports (164, 164b, 164c, 164d; 174a, 174b; 185a, 185b) arranged at the lower side of the base and adapted for axially supporting the structure on one or more upper supports (175a,175b,175c,175; 195a, 195b) of another constructional structure (170) of the platform, characterized in that the method comprises the steps of:
connecting hoisting wires (130a-130d) to or near the lower supports and below the center of mass (C) of the constructional structure, in such a manner that when an axially directed lifting force (Fa) is applied on the hoisting wires this axially directed force is substantially transferred via the lower supports (164,164b, 164c, 164d) to the rest of the base, and in such a manner that, while the axially directed lifting force is applied on the wires, the hoisting wires remain spaced apart from distal lower ends of the lower supports; and
while the constructional structure (160;170;180) is in an substantially upright orientation, lifting the constructional structure by using one or more cranes (1 10,210) to apply an axially directed lifting force (Fa) on each of the wires in such a manner that the wires extend substantially parallel to each other.
2. Method according to claim 1 , wherein the wires are connected to or near the lower supports at a location below a horizontal plane through the lower side of the base.
3. Method according to claim 1 or 2, wherein during said lifting, the sum of axial lifting forces exerted on the hoisting wires is at least 70%, preferably at least 90% of the axial force required for vertically lifting the constructional structure.
4. Method according to any one of the preceding claims, wherein the lower supports are adapted for axially supporting the constructional structure on top of the another constructional structure.
5. Method according to any one of the preceding claims, wherein the lower supports are used to bear most of the weight of the constructional structure as it is lifted using the hoisting wires, and wherein the axially directed lifting force exerted on the hoisting wires is substantially completely transferred via the lower supports to the rest of the base.
6. Method according to any one of the preceding claims, wherein the lower supports comprise or are formed as columns which extend on the lower side of the base, preferably wherein at the points where the columns are to be supported on the upper supports, the columns are oriented with their principal axes in the vertical direction.
7. Method according to any one of the preceding claims, wherein the hoisting wires are connected at or near the lower supports at a location below a horizontal plane through the lower side of the base.
8. Method according to any one of the preceding claims, wherein the hoisting wires are connected to or near the lower supports in such a manner that the hoisting wires are spaced apart from the base, and in such a manner that, when seen in projection onto a horizontal plane, each of the hoisting wires is connected to or near one of the lower supports within a distance of 3 meters from an outer periphery of the lower support.
9. Method according to any one of the preceding claims, wherein during lifting, each of the wires deviates no more than 5 degrees from the vertical, and more preferably no more than 3 degrees from the vertical, most preferably no more than 1 ,5 degrees from the vertical.
10. Method according to any one of the preceding claims, wherein during lifting, each of the wires remains substantially uncoupled from the structure, except at the ends of the hoisting wires.
1 1 . Method according to any one of the preceding claims, wherein at least two of said hoisting wires are connected to a substantially rigid lifting beam, wherein said at least two said hoisting wires are connected to the lifting beam at points substantially corresponding to two or more of the lower supports.
12. Method according to any one of claims 1 -10, wherein at least three of said hoisting wires are connected to a substantially rigid lifting frame (120), wherein said at least three hoisting wires are connected to the lifting frame at points substantially corresponding to three or more of the lower supports.
13. Method according to any one of the preceding claims, wherein the one or more cranes are arranged on one or more vessels (100) which float on the water.
14. Method according to any one of the preceding claims, wherein during said lifting the cranes are arranged on a platform which has a lower side that is in contact with and supported by the sea floor.
15. Method according to any one of the preceding claims, comprising subsequent steps of: positioning (120) the lifted constructional structure to a position in which the lower supports are substantially axially aligned with the one or more upper supports of the another constructional structure (40); and lowering (130) the constructional structure until the lower supports are substantially completely supported on the one or more upper supports of the another constructional structure.
16. Method according to any one of the preceding claims, wherein, when the constructional structure is being lifted in the upright orientation, and when viewed in projection onto a horizontal plane, the parallel portions of the wires are arranged within the peripheral edge of the base.
17. Method according to claim 16, wherein when the constructional structure is being lifted in the upright orientation, and when viewed in projection onto a horizontal plane, the area spanned by the lower supports is smaller than or equal to the area spanned by the base in said projection.
18. Method according to claim 16 or 17, wherein when the constructional structure is being lifted in the upright orientation, and when viewed in projection onto a horizontal plane, each of the lower supports is spaced apart from the peripheral edge of the base by a distance greater than or equal to 4 times a length of said lower support along its principal axis in said projection.
19. Method according to any one of the preceding claims, wherein said step of connecting the hoisting wires comprises, for each of the said hoisting wires, connecting one end of said wire to one of the lower support surfaces.
20. Method according to any one of the preceding claims, wherein one or more of the wires are provided with a sling that is directly connected to the lower support surfaces.
21 . Method according to claim 20, wherein said direct connection is achieved by tying said one or more of the wires around the lower support surface on a lower side of the base.
22. Method according to any one of the preceding claims, wherein the one or more hoisting wires are connected to the lowers supports such that, during lifting, the wires extend from the lower side of the base, through openings in the base towards the upper side of the base.
23. Method according to any one of the preceding claims, wherein one or more of said lower supports comprises a leg having a substantially cylindrical or conical leg inner surface, wherein one or more of said wires is provided at an end thereof with an internal lifting tool adapted for engaging the leg’s inner surface.
24. Method according to any one of the preceding claims, wherein one or more of said lower supports comprises a leg having a substantially cylindrical leg outer surface around which an external lifting tool is attached, wherein one or more of said wires is attached to said external lifting tool.
25. Method according to any one of the preceding claims, wherein one or more of said lower supports is provided with a padeye or trunnion to which one or more of the wires is attached.
26. Method according to claim 25, wherein the method further comprises, prior to lifting of the constructional structure, welding a reinforcement structure to the lower support, wherein the reinforcement structure is provided with a padeye or trunnion.
27. Method according to any one of the preceding claims, wherein the constructional structure comprises one or more of:
a topside, wherein the at least three spaced apart lower supports are formed by legs of the topside, and wherein the another constructional structure is a jacket;
a topside module, wherein the at least three spaced apart lower supports are formed by formed by legs of the topside module, and wherein the another constructional structure is a topside; a jacket, wherein the at least three spaced apart lower supports are formed by lower ends of legs of the jacket, and wherein the another constructional structure is a jacket foundation; a wind turbine having a base, a column which extends from the base, a nacelle at the top of the column and provided with a rotor, wherein the wind turbine further comprises at least three spaced apart legs provided at a lower side of the base and which form the lower supports.
PCT/NL2019/050398 2018-06-28 2019-06-28 Method for installation of an offshore structure using one or more cranes WO2020005066A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
NL2021201 2018-06-28
NL2021201A NL2021201B1 (en) 2018-06-28 2018-06-28 Method for installation of an offshore structure using one or more cranes

Publications (1)

Publication Number Publication Date
WO2020005066A1 true WO2020005066A1 (en) 2020-01-02

Family

ID=63145172

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/NL2019/050398 WO2020005066A1 (en) 2018-06-28 2019-06-28 Method for installation of an offshore structure using one or more cranes

Country Status (2)

Country Link
NL (1) NL2021201B1 (en)
WO (1) WO2020005066A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2021230749A1 (en) * 2020-05-15 2021-11-18 Baggermaatschappij Boskalis B.V. Method for lifting an object, assembly for lifting an object and a guiding structure for use in an assembly for lifting objects

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4744697A (en) 1985-04-29 1988-05-17 Heerema Engineering Service Bv Installation and removal vessel
CN101468774A (en) 2007-12-24 2009-07-01 中国海洋石油总公司 Hoisting supplementary structure of wind-driven generator group
US20130051924A1 (en) * 2010-03-10 2013-02-28 Stewart Willis Offshore structures and associated apparatus and methods
KR20170048737A (en) 2015-10-27 2017-05-10 대우조선해양 주식회사 Top-side module installation method and the boom rest on the top side modules support provided for offshore structures

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4744697A (en) 1985-04-29 1988-05-17 Heerema Engineering Service Bv Installation and removal vessel
CN101468774A (en) 2007-12-24 2009-07-01 中国海洋石油总公司 Hoisting supplementary structure of wind-driven generator group
US20130051924A1 (en) * 2010-03-10 2013-02-28 Stewart Willis Offshore structures and associated apparatus and methods
KR20170048737A (en) 2015-10-27 2017-05-10 대우조선해양 주식회사 Top-side module installation method and the boom rest on the top side modules support provided for offshore structures

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2021230749A1 (en) * 2020-05-15 2021-11-18 Baggermaatschappij Boskalis B.V. Method for lifting an object, assembly for lifting an object and a guiding structure for use in an assembly for lifting objects
NL2025591B1 (en) * 2020-05-15 2021-11-30 Boskalis Bv Baggermaatschappij Method for lifting an object, assembly for lifting an object and a guiding structure for use in an assembly for lifting objects

Also Published As

Publication number Publication date
NL2021201B1 (en) 2020-01-07

Similar Documents

Publication Publication Date Title
US4744697A (en) Installation and removal vessel
JP5736133B2 (en) Floating structure work system, work boat, and floating structure work method
US9896310B2 (en) Load-handling means for a tower or a tower section of a wind turbine and method for erecting a wind turbine
US7112010B1 (en) Apparatus, systems and methods for erecting an offshore wind turbine assembly
CN112771238B (en) Device and method for erecting a tubular element having a longitudinal direction from a support surface at an outer end
EP2171159B1 (en) Device and method for marine tower structure
JP7366119B2 (en) Device and method for erecting a tubular element having a longitudinal direction at its outer end
US20110305521A1 (en) Movable brace frame for self-installing platform
CN101881148B (en) Jacket riser mounting method and special riser component thereof
WO2020085902A1 (en) Installation of a wind turbine blade on a hub of a wind turbine
GB2551379A (en) Upgrading subsea foundations of mooring systems
CA3080105A1 (en) A coupling system, an assembly of a vessel and a coupling system, and an assembly of a coupling system, jacket pile and foundation pile
AU771609B2 (en) Method for removing a jacket of a drilling or production rig and vessel provided with a device therefor
WO2020005066A1 (en) Method for installation of an offshore structure using one or more cranes
CN113825878A (en) Vessel and method for installing a pile suitable for supporting an offshore wind turbine
KR20190104318A (en) Marine crane ship and how it works
JP6713342B2 (en) Installation method of jacket structure
KR20220045208A (en) How to install a floating body based on a tension leg platform
US9139260B2 (en) Tension leg connection system and method of installing
EP3260604A1 (en) Top part of a base construction
WO2012060112A1 (en) Ship for installing offshore wind turbine and method for installing offshore wind turbine using same
EP4286592A2 (en) Method of installing a support for supporting a load structure, such as a wind turbine, on, for instance, a sea bed
JP2023552909A (en) How to assemble a floating offshore wind farm
PL232649B1 (en) Method for installing the TLP-type floating platform on sea, intended for the wind power stations
EP3943380A2 (en) Floatable structure comprising a mooring system for mooring a second floating structure, and method for mooring the second floating structure

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 19749434

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 19749434

Country of ref document: EP

Kind code of ref document: A1