A method for appraising a deepwater well comprising: producing a first quantity of hydrocarbon from an undersea reservoir; transporting the first quantity of hydrocarbon to a floating vessel; off loading the first quantity of hydrocarbon from the vessel; producing a second quantity of hydrocarbon from the undersea reservoir; and transporting the second quantity of hydrocarbon to the floating vessel.

A subsea tubular system comprises extended sections of a first material and interposed sections of a second, different material that aids in damping vibration resulting from subsea dynamic conditions such as current. The vibration damping sections may make up a portion of the overall system significantly less than the sections of the first material. The number, length, and positions of the vibration damping sections may be selected based on factors such as the diameter, overall length, profile, and so forth. The system may be used as a riser or other conduit for the production of minerals such as oil and gas.

A method for reducing emissions from a vessel includes isolating the vessel from a downstream fluid flow line, purging a fluid from the vessel by injecting purging media into the vessel to push the fluid through a check valve of a vent tubing and into the downstream fluid flow line, and draining the purging media from the vessel. A first end of the vent tubing is coupled to the housing of the vessel, and a second end of the vent tubing is coupled to the downstream fluid flow line. Further, the vent tubing includes a check valve disposed between the first end and the second end, and the check valve is configured to allow fluid to flow from the housing to the downstream fluid flow line.

An apparatus, method and system for real-time monitoring of underwater risers, cables, and mooring lines based on a Kalman filter. In an embodiment, the system is formed with sensors configured to sense an inclination of a riser segment between riser nodes of the riser between the upper end and the lower end. A data processing system is configured to employ a Kalman filter algorithm to produce real-time estimates of a deformed shape and a stress of the riser segment using the sensed inclination between the riser nodes.

A disconnectable mooring system for offshore semi-submersible floating structures. A disconnectable buoy has a number of mooring lines which include a buoy chain between the mooring chain and the buoy. The mooring chain and the buoy chain are connected via a three way mooring connector, with the third connection configured to pull the mooring connector to a mooring point on the structure. In a first configuration the buoy is disconnected and supports the mooring chains for recovery at shallow depths to be pulled in. In a second configuration, the mooring lines are pulled in via the mooring connectors thereby providing a spread mooring to the structure with the buoy chain left as a catenary between the buoy and mooring point.

A disconnectable mooring system for offshore semi-submersible floating structures. A disconnectable buoy has a number of mooring lines which include a buoy chain between the mooring chain and the buoy. The mooring chain and the buoy chain are connected via a three way mooring connector, with the third connection configured to pull the mooring connector to a mooring point on the structure. In a first configuration the buoy is disconnected and supports the mooring chains for recovery at shallow depths to be pulled in. In a second configuration, the mooring lines are pulled in via the mooring connectors thereby providing a spread mooring to the structure with the buoy chain left as a catenary between the buoy and mooring point.

A transfer system for transferring a medium between a first facility and a second facility includes a first pipe spool, a compensator, a second pipe spool, a coupling assembly, a transfer skid, and pipe supports. The first pipe spool connects to a manifold on a deck of the first facility and the compensator. The second pipe spool connects to the compensator and a transfer pipe through the coupling assembly. The compensator allows a relative motion between the first and second pipe spools. The transfer pipe is connected to the second facility. The transfer skid includes an inboard assembly on a second deck of the first facility and an outboard assembly with a structural frame and pipe supports. The structural frame includes an inner cross-sectional area with pipe supports that allows passage of the second pipe spool, the coupling assembly, and the transfer pipe.