Abstract:
A method of installing a subsea pipeline having a direct tie-in between a first section of the pipeline and a subsea structure, wherein, after installation, the first section is located at a tie-in position. The method comprises: laying at least a portion of the pipeline from a laying vessel, the at least a portion of the pipeline including the first section and a second section of the pipeline, such that the first section is beyond the tie-in position in the laying direction, and the first section and the tie-in position are beyond the second section in the laying direction; either before, during or after said laying, configuring the second section such that bending will be preferentially induced in the second section of the at least a portion of the pipeline when the first section is pushed or pulled back to the tie-in position; pushing or pulling the first section back to the tie-in position, wherein, responsive to said pushing or pulling, bending is preferentially induced in the second section.
Abstract:
A pipe-in-pipe bulkhead assembly has inner and outer rings spaced in concentric relation to define a thermally-isolating gap in the annulus between them. Interlocking formations project into the annulus from each of the rings, presenting confronting faces where they overlap radially. The gap extends between the longitudinally-spaced faces. A thermally-insulating spacer is interposed between the faces in the gap to carry axial mechanical loads between the inner and outer rings. Heating elements outside the inner ring extend longitudinally beyond the gap between the faces and along a longitudinal passageway that passes through or beside an interlocking formation of the inner ring. The spacer may be positioned before or after the outer ring is placed, for example as a discrete element or as an injected mass. An additional sealing mass may also be positioned in the annulus, for example by injection, to promote a gas-tight seal.
Abstract:
A method of installing an electrically-heatable subsea flowline includes launching the flowline with at least one electric power cable attached in piggybacked relation. After landing the flowline with the piggybacked cable on the seabed, a free end portion of the, or each, cable having a length greater than the water depth is released from the flowline. This allows a free end of the, or each, cable to be recovered to the surface to be spliced to one or more power supply conductors. After lowering the, or each, cable and the, or each, connected conductor beneath the surface, the free end portion of at least one cable is reattached to the flowline on the seabed in piggybacked relation. To perform the method, a subsea flowline assembly includes subsea-releasable fastenings spaced along the cable and the flowline to attach at least an end portion of the cable releasably to the flowline.
Abstract:
A system and method for laying an underwater pipeline is provided. The present invention includes a plurality of pipe support rings connected together by tension cables. The tension cables are secured to a S or J laying ship by a winch. The plurality of pipe support rings form a pipe channel sized to guide the underwater pipeline. The present invention further includes a sea water pipe having a distal portion and a proximal end. The proximal end is fluidly connected with a pump on board the ship. The distal end includes a plurality of nozzles. The sea water pipe is disposed underneath the plurality of pipe support rings. The underwater pipeline is fed through the plurality of pipe support rings while the nozzles form a trench on a sea bed.
Abstract:
A support for an underwater pipeline, in particular configured to elevate an underwater pipeline on a bed of a body of water, with a connecting frame configured to fit to a portion of underwater pipeline extending along a longitudinal axis; and at least two legs, which are hinged to the connecting frame, and movable between a contracted configuration and an extended configuration in which they extend crosswise to the underwater pipeline to rest on the bed of the body of water.
Abstract:
A method of installing a plurality of pin piles into a seabed including at least the steps of: (a) lowering a pin pile apparatus comprising a first pin pile and an attached clump weight towards the seabed; (b) allowing the first pin pile to self-penetrate the seabed based on self-weight of the pin pile apparatus and the momentum from step (a) until the clump weight reaches the sea bed; (c) disconnecting the clump weight from the first pin pile; and (d) recovering the clump weight for use with a second pin pile and repeating steps (a)-(c). In this way, the pin piles are easily installed from their descent to the seabed with the clump weight, which can then be removed and applied to the next pin pile in an easy and repeatable operation without requiring a suction apparatus or hammer or drill.
Abstract:
Pipeline segments can contain cables, such as communication cables (e.g., fiber optic cables) within insulation material surrounding the pipeline segments. Cables can be embedded within the insulation material, run through conduits embedded within the insulation material, placed in channels formed in the insulation material, or otherwise. Channels containing one or more cables can be filled with supplemental insulation material, thus securing the cables within the channels. Pipelines created as disclosed herein can enable data transfer between distant points without the need to lay fiber optic cable in addition to the pipeline. Further, fiber optic cable embedded thusly can be used to sense conditions in the pipeline, such as leaks, seismic activity, strain, and temperature information.
Abstract:
A method of transporting a rigid tie-in connection across a body of water for installation underwater is disclosed. The method includes the step of supporting the tie-in connection in the water by buoyancy acting on a frame that supports the tie-in connection until installation. The buoyancy-supported frame is lowered and the tie-in connection into a sub-surface transit configuration. The method further includes in the transit configuration, towing the buoyancy-supported frame and the tie-in connection behind a towing vessel toward an installation site. Also disclosed is a system for implementing the method. The system includes a towable frame arranged to support the tie-in connection until installation and an external buoyancy attached to the frame by an extensible suspension link arranged to suspend the frame from the buoyancy in water in use. The link is extensible to lower the frame from a raised surface-tow configuration into a lowered sub-surface transit configuration.
Abstract:
Apparatus and methods related to pipeline freespan support are described. For example, some embodiments may contain an upper structure, which contains at least four legs connected to one another by a number of bracing members, and a number of attachment points through which the upper structure can be lifted, and a lower structure, which contains at least four posts that can be connected to, and disconnected from as needed, the four legs of the upper structure, two spaced mud mats on which the posts stand, and at least two horizontal arms that can be attached to the posts, rotate about the posts, connect to and be locked with the posts on the other mud mat, and be lifted to an appropriate height to provide suitable support at the pipeline freespan location.
Abstract:
A ship for laying flexible undersea lines at sea, the ship having a deck including a cavity receiving said turntable and a motor-driven device for rotating the turntable and fastened to the carrier structure of the hull of the ship, also known as the “hull girder”. The top face of the circular turntable does not project significantly above the plane of the deck that is juxtaposed therewith. The turntable presents attachment elements for attaching a modular storage and handling device for storing and handling flexible lines by winding and unwinding the flexible lines.