The invention involves utilizing variable reluctance measurement technology (“VRMT”) sensors to monitor forces and stresses on drilling risers and riser towers. The tension monitoring system described herein includes an optimized configuration of variable reluctance measurement technology sensors, wherein the sensors have increased wire turns around each end of their C-cores or alternatively are mounted on mechanical amplifiers or both. An array of optimized variable reluctance measurement technology sensors can be configured at multiple points on a riser system. The VRMT sensors may be integrally attached to the risers or flexible joints for the risers, or may be installed on existing riser or flexible joint systems.

A rupture disc assembly and a float tool incorporating the rupture disc assembly is disclosed. The rupture disc assembly may include a rupture disc assembly comprising a rupture disc, an upper tubular portion and a lower tubular portion, and a securing mechanism for holding the rupture disc between the upper and lower tubular portions. A float tool for creating a buoyant chamber in a casing string may include the rupture disc assembly and a sealing device for sealing the lower end of the casing string, the buoyant, sealed chamber may be created there between. In operation, applied fluid pressure causes the rupture disc to move downward. The rupture disc may be shattered by contact with a surface on the lower tubular portion. Full casing internal diameter may be restored in the region where the rupture disc formerly sealed the casing.

A rupture disc assembly and a float tool incorporating the rupture disc assembly is disclosed. The rupture disc assembly may include a rupture disc assembly comprising a rupture disc, an upper tubular portion and a lower tubular portion, and a securing mechanism for holding the rupture disc between the upper and lower tubular portions. A float tool for creating a buoyant chamber in a casing string may include the rupture disc assembly and a sealing device for sealing the lower end of the casing string, the buoyant, sealed chamber may be created there between. In operation, applied fluid pressure causes the rupture disc to move downward. The rupture disc may be shattered by contact with a surface on the lower tubular portion. Full casing internal diameter may be restored in the region where the rupture disc formerly sealed the casing.

Torque tool (200) configured for making up and breaking out joints (1a, 1b) in a riser (100), the tool (200) comprising: a tool body (3) and a tool head (4), the tool head (4) having a socket (4′) configured to receive a head (14) of a bolt (2) and apply a torque on the bolt (2), a torque sensor (20) operable to measure the torque applied on the bolt (2), and a pre-tension sensor (21) operable to measure a pre-tension in the longitudinal extension of the bolt (2) when the bolt (2) is received in the tool head (4). There is also provided a method for pre-tensioning bolted riser joints (1a, 1b) comprising a plurality of bolts (2), a method of managing a plurality of bolts (2) for riser joints (1a, 1b), a method of managing a plurality of bolts (2) for riser joints (1a, 1b), and a riser connector (101).

The present invention provides a system for coupling between a bend stiffener (1) and a bell month (2) comprising a plurality of locking mechanisms (3), wherein each locking mechanism (3) is secured externally to the bell mouth (2) and comprises a movable lug (30) positioned such as to slope downwards, in which the lug (30) accesses the interior of the bell mouth (2) and is actuated by an elastic element (34) designed to exert pressure on the lug (30) in the direction of the interior of the bell mouth (2).

What is provided is a method and apparatus wherein a swivel can be detachably connected to an annular blowout preventer thereby separating the drilling fluid or mud into upper and lower sections and allowing the fluid to be displaced in two stages, such as while the drill string is being rotated and/or reciprocated. In one embodiment the sleeve or housing can be rotatably and sealably connected to a mandrel. The swivel can be incorporated into a drill or well string and enabling string sections both above and below the sleeve to be rotated in relation to the sleeve. In one embodiment the drill or well string does not move in a longitudinal direction relative to the swivel. In one embodiment, the drill or well string does move longitudinally relative to the sleeve or housing of the swivel.

An improved multi-bolt and nut torque wrench for installing and removing bolts or nuts from flanged joints or the like which includes a plurality of torque stations having a plurality of high torque wrenches for engaging the heads of the bolts or nuts during a high torque phase of removal or installation; a plurality of low-torque motors operatively engaged with the wrenches for rotating the bolts or nuts during the low torque phase of removal or installation; a source of hydraulic fluid for driving the low-torque motors during the low-torque phase, and driving the high-torque wrenches during the high torque phase; and a mechanism for switching between the two phases depending on the torque needed.

A control system for controlling disconnection of riser system that extends between a vessel and a subsea location that comprises a wellbore, the riser system configured to receive a string in use, the control system being configured to disconnect the riser system according to a sequence of operations, the sequence of operations comprising disconnecting the riser system prior to or simultaneous with cutting the string and sealing the well bore.

A method for forming a sleeve for wrapping around and insulating a joint of a downhole tubing string is provided. The method includes the steps of providing a mold, applying insulation around the mold, winding an interfacing material around the insulation; and applying a polymer onto the interfacing material to bind to the interfacing material to form the sleeve.

A tubular for downhole use, the tubular including a pipe, an insulation layer surrounding the pipe, and a protective layer around the insulation layer and comprising a polymer. The protective layer can also include a compression layer adjacent to the insulation layer. There may be reinforcement material in the protective layer, for example encapsulated by the elastomer. The tubular may have bare portions at the ends for manipulation of the tubulars to form a tubing string. A sleeve may be provided using the same layer structure to insulate the bare portions which form joints of the tubing string. The sleeve can also include a base layer.