A drilling vessel (10) for well operations, which drilling vessel (10) comprises a derrick (20) and a crown assembly (40) on the derrick (20), the arrangement being such that, in use, said crown assembly (40) is movable between a first position and a second position, in which second position said derrick (20) has an overall height less than said first position.

A system compensates for heave induced pressure fluctuations on a floating rig when a drill string or tubular is lifted off bottom and suspended on the rig, such as when tubular connections are made during MPD, tripping, or when a kick is circulated out during conventional drilling. In one embodiment, a liquid and a gas interface moves along a flow line between a riser and a gas accumulator as the tubular moves up and down. In another embodiment, a pressure relief valve or adjustable choke allows the movement of fluid from the riser when the tubular moves down, and a pump with a pressure regulator moves fluid to the riser when the tubular moves up. In other embodiments, a piston connected with the rig or the riser telescoping joint moves in a fluid container thereby communicating a required amount of the fluid either into or out of the riser annulus. The system also compensates for heave induced pressure fluctuations on a floating rig when a riser telescoping joint located below a RCD is moving while drilling.

The present invention generally relates to an apparatus and method for compensating a landing string due to movement of a floating rig platform. In one aspect, a compensation system (100) for use with a landing string is provided. The compensation system includes a slip joint (115) member attachable to the landing string, the slip joint member having an upper portion and a lower portion. The compensation system further includes a first lock assembly (140) configured to connect the upper portion of the slip joint member to a floating rig. Additionally, the compensation system includes a second lock assembly configured to connect the lower portion of the slip joint member to a riser (40) disposed below the floating rig. In another aspect, a method for compensating a landing string due to movement of a floating rig is provided.

The invention relates to a hoisting device (1) for a vessel, comprising a mast (2), on the top side provided with cable blocks; a trolley (10), which is movably fixed on the mast (2), on the top side is provided with cable blocks, and on the bottom side is provided with means (12) for gripping a load; hoisting means, at least equipped with a hoisting cable (16) and a winch (18, 19), said hoisting cable (16) being guided over the cable blocks of both the mast and the trolley, and it being possible to move the trolley (10) relative to the mast (2) with the aid of the hoisting means; and a compensator (21), in the form of a pneumatic or hydraulic cylinder, for damping movements of the vessel (70) as a result of heave and beating of the waves, the hoisting cable (16) being guided over cable pulleys (20) which are connected to the end of the compensator (21), all the above in such a way that force can be exerted upon the hoisting cable (16) with the aid of the compensator.

A system compensates for heave induced pressure fluctuations on a floating rig when a drill string or tubular is lifted off bottom and suspended on the rig, such as when tubular connections are made during MPD, tripping, or when a kick is circulated out during conventional drilling. In one embodiment, a liquid and a gas interface moves along a flow line between a riser and a gas accumulator as the tubular moves up and down. In another embodiment, a pressure relief valve or adjustable choke allows the movement of fluid from the riser when the tubular moves down, and a pump with a pressure regulator moves fluid to the riser when the tubular moves up. In other embodiments, a piston connected with the rig or the riser telescoping joint moves in a fluid container thereby communicating a required amount of the fluid either into or out of the riser annulus. The system also compensates for heave induced pressure fluctuations on a floating rig when a riser telescoping joint located below a RCD is moving while drilling.

A drilling vessel (10) for well operations, which drilling vessel (10) comprises a derrick (20) and a crown assembly (40) on the derrick (20), the arrangement being such that, in use, said crown assembly (40) is movable between a first position and a second position, in which second position said derrick (20) has an overall height less than said first position.

A computer controlled heave compensation wireline logging winch system and method of use that compensates for the effects of wave motion on floating installations performing wireline logging measurements. A wireline winch and wireline cable with a logging measurement tool attached is installed on a floating installation. Vessel vertical movement is measured and is physically compensated for by a change in speed of the wireline cable so that the logging data is obtained at a controlled speed. Any error in this physical compensation is detected by a depth measurement system and is used to adjust the true depth at which the logging tool measurements are being recorded.