The present invention relates to a motion compensation system for an element hanging from a mobile unit, the system comprising two blocks, at least two articulated arms, a compensation cylinder and a cable. According to the invention, at least one characteristic length of the articulated system (for example: the length of a link or the distance between two sheaves of two articulated arms) is adjusted according to the motion to be compensated for.

The compensating device has a through passage that goes to the borehole tool. There is a lateral passage to a piston housing. Through the use of a differential piston area on the outer housing, a net uphole force results from backpressure as a result of flow pumped through a section mill that mills in an uphole direction. If the vessel goes down the mill is just pushed away from the tubular being cut. If wave action takes the vessel up fluid is displaced back into the mandrel but the constant force up that is dependent on the existing backpressure in the tubing keeps a steady uphole force on the mill. The tool can be reversed for applications that require a net down force during milling. Rotational locking between the mandrel and the outer housing can be used. Ports are sized to prevent damping responses.

The system for inserting a tubular member from a surface into a subsea well includes a riserless vessel, a surface injector being mounted on the vessel at the surface and delivering tubular member, such as coiled tubing, to the subsea well from the surface, a subsea snubbing jack releasably engaged to the tubular member, a subsea hydraulic power unit connected to the snubbing jack, and a device to maintain tension of the tubular member between the surface injector and the snubbing jack. The dynamic control of the subsea snubbing jack provides either active additional force for pipe light and pipe heavy conditions or passive support of the tubular member for equilibrium conditions without a riser. The method is responsive to transitions between well conditions. A riserless system without a subsea injector can more efficiently and reliably insert coiled tubing under various well conditions and during changes in the well conditions.

The system for inserting a tubular member from a surface into a subsea well includes a riserless vessel, a surface injector being mounted on the vessel at the surface and delivering tubular member, such as coiled tubing, to the subsea well from the surface, a subsea snubbing jack releasably engaged to the tubular member, a subsea hydraulic power unit connected to the snubbing jack, and a device to maintain tension of the tubular member between the surface injector and the snubbing jack. The dynamic control of the subsea snubbing jack provides either active additional force for pipe light and pipe heavy conditions or passive support of the tubular member for equilibrium conditions without a riser. The method is responsive to transitions between well conditions. A riserless system without a subsea injector can more efficiently and reliably insert coiled tubing under various well conditions and during changes in the well conditions.

An offshore drilling rig including a drill floor deck having one or more holes, each defining a well center; one or more masts upwardly extending relative to the drill floor deck, and one or more hoisting systems, each supported by at least one of the one or more masts and configured for hoisting and lowering tubular equipment through at least one of the one or more well centers; a storage area for accommodating marine riser joints in upright orientation side by side in respective upright storage positions; a riser handling apparatus, different from the hoisting systems, adapted to move at least one of said marine riser joints along a movement path between its upright storage position and a prostrate maintenance/transfer position on a maintenance/transfer area, which movement path does not intersect any of the well centers.

The invention is a system for controlling the relative movement of a load P, comprising at least one main damper having a longitudinal action of stroke C and two ends with one end being connected to a frame and the other being connected to the load. A compensation device is included having at least one secondary damper of longitudinal action with two ends with one end being secured to the frame and the other end is connected to the end of the main damper connected to the load The secondary damper is arranged so that, at one point of stroke C, the secondary damper has an action orthogonal in direction to the direction of the movement.

The invention is a land drilling rig (10) having a drilling mast (12), a top drive (14) movable in the drilling mast (12) along the vertical axis of the drilling mast (12), and a crown bearing (18) at an upper end (16) of the drilling mast (12), the crown bearing (18) being movable by means of a positioning device (24), and a method of operating such a drilling rig (10) and a method of operating a top drive (14) in the drilling mast (12) of such a drilling rig (10).

An offshore production system includes a surface vessel, a tubular tendon extending between the surface vessel and a lower connection system disposed at a seabed, the riser coupled to the surface vessel with an upper connection system, and an electrical cable extending through a central passage of the tubular tendon, wherein the upper connection system comprises a connector that physically supports the electrical cable.

A coiled tubing string may be moved into and/or out from water by deploying an open water coiled tubing control system at sea such as via a vessel. The open water coiled tubing control system comprises a reel configured to accept a coiled tubing string, a surface injector, a reel tensioner configured to control an arch formed by the coiled tubing string between the reel and the surface injector, a controller, a subsea assist jack, and a predetermined set of a predetermined set of sensors. Motion of the surface injector and the subsea assist jack are used in part to move the coiled tubing string accepted by the reel into and/or out of a subsea well by receiving various information at the controller from the predetermined set of sensors and using the controller to resolve the received information to move the coiled tubing string into or out from the subsea well at a predetermined desired speed to achieve an outcome commanded by a single input from an operator.

A coiled tubing string may be moved into and/or out from water by deploying an open water coiled tubing control system at sea such as via a vessel. The open water coiled tubing control system comprises a reel configured to accept a coiled tubing string, a surface injector, a reel tensioner configured to control an arch formed by the coiled tubing string between the reel and the surface injector, a controller, a subsea assist jack, and a predetermined set of a predetermined set of sensors. Motion of the surface injector and the subsea assist jack are used in part to move the coiled tubing string accepted by the reel into and/or out of a subsea well by receiving various information at the controller from the predetermined set of sensors and using the controller to resolve the received information to move the coiled tubing string into or out from the subsea well at a predetermined desired speed to achieve an outcome commanded by a single input from an operator.