Systems and methods for pressure communication within a hydro-pneumatic cylinder are provided. The hydro-pneumatic cylinder generally includes a rod, a barrel coaxial to the rod, and a piston assembly disposed within the barrel and connected to the rod. The barrel is hollow to define a chamber, and the piston assembly is axially movable within the chamber to stroke the rod relative to the barrel. The hydro-pneumatic cylinder includes: a flow path formed axially through the rod of the cylinder. This flow path may allow for pressure communication between a low-pressure side of the cylinder and a pressure energized lower pin located at a distal end of the rod. The lower pin may be actuated, via this pressure communication to secure the end of the cylinder to a tension ring on a riser.

Systems and methods for pressure communication within a hydro-pneumatic cylinder are provided. The hydro-pneumatic cylinder generally includes a rod, a barrel coaxial to the rod, and a piston assembly disposed within the barrel and connected to the rod. The barrel is hollow to define a chamber, and the piston assembly is axially movable within the chamber to stroke the rod relative to the barrel. The hydro-pneumatic cylinder includes: a flow path formed axially through the rod of the cylinder. This flow path may allow for pressure communication between a low-pressure side of the cylinder and a pressure energized lower pin located at a distal end of the rod. The lower pin may be actuated, via this pressure communication to secure the end of the cylinder to a tension ring on a riser.

A method and apparatus for tapping into a pressurized multiple strings of coaxially situated tubulars for wells and/or platforms which have overturned wherein the tapping occurs underwater via a diver or remotely operated vehicle. The assembly includes a tapping tool connectable to the tubular via a saddle connection and an adjustable tapping clamp with adjustable support/locking feet, compression plate with view ports, and angularly adjustable hot tapping system, along with a drill/saw system.

A method and apparatus for tapping into a pressurized multiple strings of coaxially situated tubulars for wells and/or platforms which have overturned wherein the tapping occurs underwater via a diver or remotely operated vehicle. The assembly includes a tapping tool connectable to the tubular via a saddle connection and an adjustable tapping clamp with adjustable support/locking feet, compression plate with view ports, and angularly adjustable hot tapping system, along with a drill/saw system.

A subsea riser is installed by lowering at least one riser conduit to the seabed when piggybacked to an elongate support that comprises at least one flowline. The elongate support may be a pipeline bundle, which may be attached to one or more towheads in a towable bundle unit. The riser conduit may be in fluid communication with the flowline. At the seabed, a free end portion of the riser conduit is detached from the elongate support by releasing subsea-releasable fastenings. Then, with the elongate support and a root end of the riser remaining at the seabed, the detached free end portion of the riser conduit is lifted away from the elongate support to a riser support, such as a platform, an FPSO (floating production, storage and offloading vessel), or a buoy.

Insulating fluids for use in drilling, production, and other applications are provided, the insulating fluids containing a porous medium (such as a sponge or foam) to limit the mobility of the liquid phase of the insulating fluid. The porous medium in the insulating fluid provides a mechanical means for reducing convective heat transfer, as the small pore spaces within the porous media create tortuous paths for the liquid moving therethrough. Methods include introducing the insulating fluid into an annulus of a drilling, riser, production, packer, or pipeline assembly to reduce heat transfer therethrough.

Insulating fluids for use in drilling, production, and other applications are provided, the insulating fluids containing a porous medium (such as a sponge or foam) to limit the mobility of the liquid phase of the insulating fluid. The porous medium in the insulating fluid provides a mechanical means for reducing convective heat transfer, as the small pore spaces within the porous media create tortuous paths for the liquid moving therethrough. Methods include introducing the insulating fluid into an annulus of a drilling, riser, production, packer, or pipeline assembly to reduce heat transfer therethrough.

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 subsea catenary riser comprises a rigid riser pipe that is suspended from a floating support on the surface and extends through a sagbend to the seabed. A hang-off interface allows rotation or pivoting of the riser pipe relative to the support about mutually orthogonal horizontal axes. A subsea buoy is positioned on the riser pipe above the sagbend. The buoy applies buoyant upthrust force to the riser pipe via an attachment interface that allows rotation or pivoting of the riser pipe relative to the buoy about mutually orthogonal horizontal axes. In response to movement of the support, the riser pipe deflects with S-shaped curvature to vary the inclination, relative to the buoy, of the portion of the riser pipe to which the buoy is attached. The curvature comprises mutually opposed curves respectively above and below the buoy, joined by a region of inflection that coincides with the buoy.

A buoyancy module (10, 12, 14) configured for mounting on an elongate underwater member (16) and provided with a sensor module dock (32) for receiving and releasably retaining a sensor module (30).