Abstract: Systems and methods are disclosed for deploying one or more anchor piles on the seafloor using submersible line tensioning systems and techniques to achieve tensioning of mooring lines at the seafloor rather than at the conventional vessel deck level. Among other things, the disclosed systems and methods may be advantageously employed for tensioning mooring lines for Mobile Offshore Drilling Units (MODUs) when additional mooring legs must be added to the original complement of MODU legs, as well as and for tensioning mooring lines for vessels having turret mooring systems, each of which have limited space for surface tensioning equipment.

Abstract: Methods and apparatus are disclosed for deploying one or more plate anchors on the seafloor prior to later installation (embedment) of the plate anchors using an installation tool such as a suction follower. The methods and apparatus may be used for batch-setting multiple plate anchors on the seafloor for a drilling vessel mooring in which the plate anchors and an installation tool are subsequently engaged for subsequent suction embedment of the plate anchors to design penetration depth.

Abstract: Methods and apparatus are disclosed for a self-directed (i.e., autonomous), steerable gravity-embedded anchor. This anchor free-falls through the water column, accelerates due to gravity and uses its kinetic energy to embed itself into the seafloor so as to function as an anchor for mooring of both floating vessels and other underwater structures. Unlike existing gravity-embedded plate anchors, this device can steer itself to its intended target location on the seafloor, enhancing placement accuracy and allowing release directly from an installation vessel on the water surface, thereby greatly simplifying installation.

Abstract: Releasable mooring systems and methods for drilling vessels that may be implemented with dockable and releasable mooring buoys to provide for both a quick disconnect of the mooring system from a drilling vessel and for re-connection of the drilling vessel when the vessel returns to the well site.

Abstract: Releasable mooring systems and methods for drilling vessels that may be implemented with dockable and releasable mooring buoys to provide for both a quick disconnect of the mooring system from a drilling vessel and for re-connection of the drilling vessel when the vessel returns to the well site.

Abstract: A depth compensated passive eave compensator comprises a first cylinder connected at its upper end to a vessel. A piston rod extends from a piston located within the first cylinder through the lower end thereof and is connected to subsea equipment. A second cylinder contains a compressed gas which maintains pressure beneath the piston of the first cylinder. The upper end of the first cylinder is connected to the upper end of a third cylinder having a piston mounted therein. A piston rod extending from the piston of third cylinder extends through the lower end thereof thereby applying the pressure of the sea to the piston of the third cylinder.

Abstract: The present disclosure generally provides apparatus and methods for removing a subsea well head. The apparatus may include an embedded shear comprising a pile and a shear cutter integrated into the pile. The shear cutter may be mounted within the pile near a lower end thereof. The pile may include a well head conductor receptacle adapted to receive a subsea well head, and the shear cutter may include a shear blade that extends across the well head conductor receptacle when activated. The method may include providing a pile with a shear cutter integrated therein, lowering the pile over the well head, pumping water out of the pile to drive the pile into the seafloor to a desired cutting depth, activating the shear cutter to cut off a portion of the well head, and pumping water into the pile to drive the pile out of the seafloor.

Abstract: An anchor handling/tug/supply (AHTS) vessel is employed to engage conductor casings with the seafloor. The conductor casings initially penetrate the seafloor to a first depth under their own weight. The conductor casings may optimally be further engaged with the seafloor to a second depth by the application of suction to the interiors thereof or by the use of a drop hammer. The conductor casings are driven to grade by a hydraulic pile driving hammer deployed from the deck of the AHTS vessel the previously deployed conductor casings to grade before being recovered to the deck of the AHTS vessel.