A system for cutting an underwater structure, the system comprising: a cutting head, said cutting head comprising: an abrasive water jetting nozzle; a cryogenic nozzle; said abrasive water jetting nozzle and cryogenic nozzle mounted in fixed spaced relation; said cutting head arranged to position tips of the nozzles proximate to a cutting surface, and arranged to form a cutting zone defined by the nozzle tips and cutting surface; wherein a water repelling shield is located about said cutting zone and arranged to hinder water entering said cutting zone.

A system for cutting an underwater structure, the system comprising: a cutting head, said cutting head comprising: an abrasive water jetting nozzle; a cryogenic nozzle; said abrasive water jetting nozzle and cryogenic nozzle mounted in fixed spaced relation; said cutting head arranged to position tips of the nozzles proximate to a cutting surface, and arranged to form a cutting zone defined by the nozzle tips and cutting surface; wherein a water repelling shield is located about said cutting zone and arranged to hinder water entering said cutting zone.

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 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 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 wellbore is plugged using a bismuth alloy. The wellbore is arranged so that a liquid bismuth alloy sets with an excess pressure of the plug relative to the borehole fluid pressure along a desired seal height distance.

A wellbore is plugged using a bismuth alloy. The wellbore is arranged so that a liquid bismuth alloy sets with an excess pressure of the plug relative to the borehole fluid pressure along a desired seal height distance.

A ball valve is provided. The ball valve includes a housing, a ball seat arranged in the housing, a ball member mounted within the housing and being rotatable relative to the ball seat between open and closed positions, the ball seat and ball member defining respective through bores, the ball member including a sealing surface, a bore surface and a leading edge surface extending between the sealing surface and the bore surface, the leading edge surface being configured to cut a body extending at least partially through the valve upon closure of the ball member, wherein said leading edge surface is truncated. The ball member may include a relief region proximate the leading edge surface.