A foundation for a subsea assembly is provided. The foundation includes connection points. The connection points permit other components to be connected to the foundation and permit loads to transfer from the other components into the foundation. The foundation may be a suction anchor. A method of converting an exploration well using the foundation to a production well is also provided.

A method includes mounting a platform deck block to a tower. The platform deck block (500) includes a first frame (515) defining a deck, a plurality of first conductor tubes (505) connected to the first frame, a first plurality of releasable connectors (520) coupled to the first conductor tubes, and a plurality of docking receptacles (800A,800B,800C) defined in the deck. The tower includes a second frame (415), a plurality of second conductor tubes (405) connected to the second frame, and a second plurality of releasable connectors (420) coupled to the second conductor tubes and engaging the first plurality of releasable connectors coupled to the first conductor tubes. The method further comprises mounting a first production block (600) to one of the plurality of docking receptacles.

Disclosed is a pile-cylinder-truss composite offshore wind turbine foundation. The pile-cylinder-truss composite offshore wind turbine foundation includes a truss structure, a suction cylinder and a pile foundation. The suction cylinder is connected to a bottom portion of the truss structure, and an embedded sleeve for mounting the pile foundation is provided on the suction cylinder. The embedded sleeve is located inside, at an edge of or outside the suction cylinder. The present invention also provides a construction process of the pile-cylinder-truss composite offshore wind turbine foundation.

In a general aspect, suction anchors are disclosed that include a tubular body formed at least in part of cementitious materials. The tubular body has a closed end, an open end, and a perimeter wall. The perimeter wall defines a shape of the tubular body and is former at least in part of the cementitious materials. The tubular body also includes a channel internal to the perimeter wall defining a spiral around a longitudinal axis of the tubular body. The tubular body additionally includes an edge defining an opening for the open end. The edge is configured to penetrate the underwater floor. The suction anchors also include a post-tensioning device through the channel in a tensioned state and a port configured to fluidly-couple at least part of a cavity within the tubular body to an exterior of the tubular body.

The present invention relates to a method for installing an offshore wind turbine at a target location at sea with an installation vessel, the vessel comprising:—a nacelle support structure for temporarily supporting a nacelle comprising a hub having a plurality of root end connectors to which the root ends of the blades are to be connected, the nacelle support structure comprising:—a support tower extending upwardly from a deck of the installation vessel,—a support platform configured to temporarily support the nacelle,—one or more lifting devices configured for:—lifting the nacelle onto the support platform,—lifting a nacelle assembly including the blades onto a wind turbine mast located adjacent the vessel, wherein the method comprises: a) lifting the nacelle onto the support platform, and securing the nacelle to the support platform, b) orienting a root end connector of the hub of the nacelle in a direction facing a guide path of the blade moving system, c) connecting the root end of the first blade to the corresponding first root end connector of the hub, d) repeating steps b) and c) for subsequent blades and root end connectors until all blades are connected to the hub of the nacelle, thereby providing a RNA, e) lifting the RNA from the nacelle support structure and positioning the RNA onto a wind turbine mast located adjacent the vessel.

A method includes mounting a platform deck block to a tower. The platform deck block (500) includes a first frame (515) defining a deck, a plurality of first conductor tubes (505) connected to the first frame, a first plurality of releasable connectors (520) coupled to the first conductor tubes, and a plurality of docking receptacles (800A,800B,800C) defined in the deck. The tower includes a second frame (415), a plurality of second conductor tubes (405) connected to the second frame, and a second plurality of releasable connectors (420) coupled to the second conductor tubes and engaging the first plurality of releasable connectors coupled to the first conductor tubes. The method further comprises mounting a first production block (600) to one of the plurality of docking receptacles.

A method includes mounting a first jacket connector block (400) to an apparatus. The first jacket connector block includes a first frame (415), a plurality of first conductor tubes (405) connected to the first frame, a first plurality of releasable connectors (420) coupled to first ends of the first conductor tubes, and a second plurality of releasable connectors (420) coupled to second ends of the first conductor tubes and engaging the apparatus.

A method includes providing a lower platform block (300) including a first frame (315), a plurality of docking tubes (305) connected to the first frame, and a plurality of first conductor tubes (310) connected to the first frame. At least a first jacket connector block (400) including a second frame (415) and a plurality of second conductor tubes (405) connected to the second frame is releasably coupled to the lower platform block to align the second conductor tubes with the first conductor tubes. A platform deck block (500) including a third frame (515) defining a deck and a plurality of third conductor tubes (505) connected to the third frame is releasably coupled to the first jacket connector to align the third conductor tubes with the first conductor tubes.

A cofferdam is disclosed that includes an open frame structure having double walls defining a hollow space within each double wall, with each double wall having an open bottom end and a closed top end. Each of the double walls are configured to act as suction piles allowing liquid to be removed from the space within each double wall to thereby induce negative pressure when the cofferdam is installed in a sub-sea configuration. Each of the double walls may include a plurality of partitions respectively defining a plurality of suction piles, the suction piles fluidically coupled by a manifold that may allow liquid to be removed from the suction pile to thereby drive the cofferdam structure into the subsea surface due to the induced negative pressure. A further embodiment cofferdam structure includes an open frame structure and one or more suction piles attached to the open frame structure.

An unmanned wellhead platform (1) (UWP) comprising a jacket (10) designed and adapted to be supported on the seabed and projecting above the sea level is shown. The unmanned wellhead platform (1) includes a topside installed on top of the jacket (10). The topside is designed as a standardized base concept tailored for repetitive future topside constructions (3). Each topside construction (3) is adapted to the number of wells to be developed. The topside construction (3) is made up by a number of different but standardized sections (4). Each standardized section (4) is dedicated for a particular and predetermined purpose and location in the topside construction (3).