A subsea foundation for installation on a sea floor. The subsea foundation includes a receptacle which receives a wellhead housing, and a conductor pipe which is arranged to extend from the receptacle and which receives a well pipe therethrough. The conductor pipe has a first section and a second section. The first section of the conductor pipe has a first end and a second end. The first section is connected to the receptacle at the first end and is pivotably connected to the second section at the second end so that the conductor pipe has a compact configuration, in which the conductor pipe comprises a bend therein, and an extended configuration, in which the conductor pipe is substantially straight.

A foundation (1) for a structure. The foundation (1) has a body (2) for insertion into a soil in an insertion direction during installation. The body (2) has a toe (8) at its distal end. The toe (2) defines an aperture (11) into an internal cavity (15). Movement of the toe (2) through the soil displaces soil laterally into a displaced soil region within the internal cavity (15). One or more nozzles (10) are provided for directing a fluid to the displaced soil region during installation for transporting soil away from the displaced soil region. A pumping system (24) is also provided for evacuating fluid from the internal cavity (15) during installation for reducing the soil suspension pressure within the displaced soil region.

A foot pad removably attachable to a machine and that supports the machine for operation in a fluid. The foot pad includes a support frame, a skirt coupled to the support frame, a bellows coupled to the skirt, a plenum arranged to move within the skirt, a seal between the plenum and the skirt, and a flexible bellows that allows the foot pad to be secured to, or within, a substrate. The skirt includes an edge that can be embedded in a penetrable substrate. The plenum is configured to pump the fluid into or out of a volume formed by a space below the plenum, the interior of the skirt, and the substrate, thus compressing or decompressing the fluid in the space inside the skirt. The foot pad may also include a rolling, flexible diaphragm to seal the space between the plenum and the skirt, wherein the rolling diaphragm minimized the wear compared to other seal mechanisms. The flexible bellows may include a set of radial ridges that aid in sealing the footpad to the substrate.

In a general aspect, suction anchors are presented for securing structures to an underwater floor. The suction anchors include a tubular body formed at least in part of cementitious materials and having a closed end and an open end. The tubular body 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 port configured to fluidly-couple a cavity within the tubular body to an exterior of the tubular body. The suction anchors additionally include a pad eye extending from an outer surface of the tubular body and configured to couple to a mooring line. In another aspect, methods of manufacturing the suction anchors are also presented.

Suction failure due to a piping effect when installing a suction pile underwater is mitigated by laying at least one substantially impermeable mat on the seabed. An entrance of a piping channel extending under a skirt of the pile from a seabed location to a suction chamber of the pile is identified. The mat is laid to cover the entrance to restrict or block a flow of water entering the piping channel.

A suction anchor has a skirt open at one end and closed at another end to define an interior volume. At least one conduit nested within or adjacent to the skirt, is open at one end and closed at another end to define an inner volume. A suction line is fluidly connected to the interior volume through a first valve. A second valve is fluidly connected between the inner volume and either the suction line or the interior volume. The first valve and the second valve are operable to cause water flow at respective selected rates along both the skirt and the conduit from a body of water when the interior volume and the inner volume are evacuated and the suction anchor is disposed on the bottom of a body of water.