A semi-submersible drilling vessel has a deckbox structure and a shaker room. A downward sloping mud return line is provided that passes mud from the diverter to the shaker room. In the shaker room there are one or more shale shaker devices, one or more upstream mud tanks arranged to receive gas cut mud from the one or more shale shaker devices, and a vacuum degasser having an inlet pipe extending into an upstream mud tank, a vacuum tank, a vacuum pump, and an outlet, and a degassed mud tank receiving degassed mud from the outlet of the vacuum degasser. The degassed mud tank has an effective height between the bottom thereof to the operational mud level in said degassed mud tank that is greater than the corresponding effective height of said one or more upstream mud tanks. The degassed mud tank is mounted so that—in operation—the operational mud level in said degassed mud tank is at least 1.5 meter, preferably at least 2 meters, higher than in said one or more upstream tanks with the vacuum degassers self-suction effect causing the mud to be pumped from the upstream tank, via the vacuum degasser, into the degassed mud tank.

A method for predicting heaving motion parameters of a semi-submersible offshore platform based on heaving acceleration includes: in heaving motion of a semi-submersible offshore platform, representing heaving acceleration of the semi-submersible offshore platform based on a linear potential flow theory; considering a noise influence of a heaving motion measurement marine environment, a low-frequency influence caused by a slow change of the environment and an influence caused by a baseline drift error of an acceleration sensor, introducing a noise term, a low-frequency change term and a baseline drift error term, and uniformly representing the noise term, the low-frequency change term and the baseline drift error term by a unified Prony sequence; and removing a drift term from uniformly represented heaving acceleration, establishing a relationship between the heaving acceleration and heaving motion parameters in terms of the remaining Prony sequence with the drift term being removed, and estimating the heaving motion parameters.

An offshore facility evacuation system that includes a submerged-floating pod (SFP) unit adapted to be positioned in a body of water adjacent an offshore facility, and a SFP station of the offshore facility adapted to launch the SFP unit from the facility. The SFP unit including a SFP controller, an SFP escape line to extend between the SFP station and the SFP unit to provide a path for moving persons from the SFP station to the SFP unit while the SFP unit is floating in the body of water, a SFP landing base including an inflatable platform to provide a landing area for persons, a SFP depth control system to regulate submergence of the SFP unit, a SFP location control system to control a location of the SFP unit, and a SFP communication system to provide communication with the SFP unit, and personal evacuation devices (PEDs).

This invention relates generally to geotechnical rig systems and methods. In one embodiment, a rig for sampling, includes, but is not limited to, a frame configured to deploy a drill string; at least one docking base disposed on the frame; at least one carousel with one or more addressed slots to stow one or more components, the at least one carousel being releasably coupled to the at least one docking base; and at least one arm that is configured to controllably retrieve and/or position the one or more components.

An offshore structure for drilling and/or producing a subsea well includes a hull having a longitudinal axis, a first end, and a second end opposite the first end. The hull includes a plurality of parallel elongate columns coupled together. Each column includes a variable ballast chamber positioned axially between the first end and the second end of the hull and a first buoyant chamber positioned between the variable ballast chamber and the first end of the hull. The first buoyant chamber is filled with a gas and sealed from the surrounding environment. The offshore structure also includes an anchor fixably coupled to the second end of the hull and configured to secure the hull to the sea floor. The anchor has an arrow-shaped geometry and a central axis coaxially aligned with the longitudinal axis of the hull. The anchor includes angularly-spaced penetration members extending radially from the central axis of the anchor. In addition, the offshore structure includes a topside mounted to the first end of the hull.

The first aspect of the present invention relates to an offshore drilling system and a method for performing subsea wellbore related activities involving a riser extending between the vessel and a subsea wellbore. The offshore drilling system comprising a drilling vessel with a floating hull, a drilling tower and a tubular string main hoisting device. A vertically mobile working deck with a rig floor slip device is positioned above the moonpool. A telescopic joint and a diverter are provided, wherein the inner barrel of the telescopic joint is secured to the diverter via a flexible joint. Furthermore an integrated heave compensation system is provided such that said travelling block and the mobile working deck move synchronously in heave compensation.

An “outboard pontoon” semisubmersible floating platform for the use of offshore applications has a hull configuration including vertical deck support columns and a horizontally disposed pontoon structure. The vertical columns support the deck structure at upper ends and adjoin pontoon at their lower ends. Under the premise of ensuring platform stability, structural feasibility, and structural cost efficiency, the pontoon is horizontally extrapolated as far as possible radially outward from platform center in the horizontal plan while the elevation of the bottom of columns ranges anywhere from the pontoon bottom to the top surface of the pontoon. The vertical columns are adjoined to the pontoon from its inner periphery and the central vertical axis of each column resides a distance inward from the closest point of the center line of the pontoon. This arrangement makes part of pontoon become the “outboard pontoon” which is the important concept introduced by this invention. The “outboard pontoon” and the raised bottom elevation of the vertical columns will play an important role to reduce the vertical motion response of the platform to the sea waves, which has solid theoretical basis in hydrodynamics. Risers can be supported on the pontoon and columns, be extended to the deck, and the structure can be anchored by mooring lines extending along the outboard face of the outboard columns extending radially outward and downward from their lower ends.

Systems, devices and methods enable generation and monitoring of support platform structural conditions in a manner that overcomes drawbacks associated with conventional approaches (e.g., load cells) for generating and monitoring similar operating condition information. In preferred embodiments, such systems, devices and methods utilize fiber optic strain gauges (i.e., fiber optic sensors) in place of (e.g., retrofit/data replacement) or in combination with conventional load cells. The fiber optic sensors are strategically placed at a plurality of locations on one or more support bodies of a support platform. In preferred embodiments, the fiber optic strain gauges are placed in positions within a hull and/or one or more pontoons of an offshore platform. Such positions are selected whereby resulting operating condition data generated by the fiber optic strain gauges suitably replaces data received by conventionally constructed and located load cells of an offshore platform (e.g., a TLP).

A platform assembly for providing a work area around a well riser is disclosed. The platform assembly comprises a platform configured to be attached to the well riser. The platform assembly further comprises a plurality of tensioning means for supporting the platform relative to a vessel and for supporting the riser. At least part of tensioning means is configured to change in length relative to another part of tensioning means responsive to angular motion of the riser and the vessel.

This invention relates generally to geotechnical rig systems and methods. In one embodiment, a rig for sampling, includes, but is not limited to, a frame configured to deploy a drill string; at least one docking base disposed on the frame; at least one carousel with one or more addressed slots to stow one or more components, the at least one carousel being releasably coupled to the at least one docking base; and at least one arm that is configured to controllably retrieve and/or position the one or more components.