Abstract: A technique facilitates controlling barrier fluid via a mechanical pressure regulation system which may be coupled with a rotating machine at a subsea location. The mechanical pressure regulation system enables controlled supply of the barrier fluid to the rotating machine and comprises a mechanical valve mechanism. The mechanical valve mechanism automatically maintains a pressure differential between the barrier fluid and a process fluid within a desired range. According to an embodiment, the mechanical valve mechanism is mechanically actuated via pressures applied to a pilot piston so as to provide barrier fluid to the rotating machine when the pressure differential reaches a lower limit and to dump barrier fluid when the pressure differential reaches an upper limit.

Abstract: A contra-rotating compressor includes a first shaft assembly disposed in a housing, the first shaft assembly including an outer shaft, and a first plurality of impellers coupled to the outer shaft, wherein the outer shaft includes a final stage that includes a final impeller of the first plurality of impellers, a second shaft assembly disposed in the housing and rotatable about the longitudinal axis, the second shaft assembly including a second plurality of impellers, a first pair of annular seals between the final stage and an inner surface of the housing, the pair of annular seals being configured to permit relative rotation between the final stage and the housing, and a third annular seal positioned between the outer surface of the final stage and an inner surface of the second shaft assembly, the third annular seal configured to permit contra-rotation between the final stage and the second shaft assembly.

Abstract: A technique facilitates controlling barrier fluid via a mechanical pressure regulation system which may be coupled with a rotating machine at a subsea location. The mechanical pressure regulation system enables controlled supply of the barrier fluid to the rotating machine and comprises a mechanical valve mechanism. The mechanical valve mechanism automatically maintains a pressure differential between the barrier fluid and a process fluid within a desired range. According to an embodiment, the mechanical valve mechanism is mechanically actuated via pressures applied to a pilot piston so as to provide barrier fluid to the rotating machine when the pressure differential reaches a lower limit and to dump barrier fluid when the pressure differential reaches an upper limit.

Abstract: A system for dewatering a subsea gas pipeline includes a pig launcher at the pipeline's upper end, which may be at or near the sea surface, and a pig receiver at the pipeline's lower end, which may be at or near the sea floor. A multiphase pump unit is deployed at the pipeline lower end and is configured to provide sea water suction to aid in a pig train being forced downwards through pipeline. The multiphase pump is configured to handle some amount of gas leaking around the pig train. A choke system may allow sea water to enter the flowline, thereby lowering the gas volume fraction (GVF) and preventing the GVF from exceeding the ability of the multiphase pump. For deeper water applications, a second pump may be provided in series that may be a single pump if positioned downstream of the multiphase pump.

Abstract: A contra-rotating compressor includes a first shaft assembly disposed in a housing, the first shaft assembly including an outer shaft, and a first plurality of impellers coupled to the outer shaft, wherein the outer shaft includes a final stage that includes a final impeller of the first plurality of impellers. The compressor further includes a second shaft assembly disposed in the housing and rotatable about the longitudinal axis that has a second plurality of impellers, a first pair of annular seals between the final stage and an inner surface of the housing that are configured to permit relative rotation between the final stage and the housing, and a third annular seal positioned between the outer surface of the final stage and an inner surface of the second shaft assembly that is configured to permit contra-rotation between the final stage and the second shaft assembly.

Abstract: A flowline dewatering system comprising at least one pump and a pig train supported by a gas pressure enabling suction conditions for the pump. A method to dewater a flowline using the system.

Abstract: In rotating machine having a vertically oriented rotating shaft, a static magnetic force is used to simulate rotor weight and create the desired bearing preload. By installing a magnet the gravity based preload on the shaft journal bearings of a horizontal machine can be simulated for a vertical shaft. This can increase rotor stability, reduce the machine's vulnerability to hydraulically induced imbalance forces and give a more smooth transition through various shaft speeds.

Abstract: A contra-rotating compressor includes a first shaft assembly disposed in a housing, the first shaft assembly including an outer shaft, and a first plurality of impellers coupled to the outer shaft, wherein the outer shaft includes a final stage that includes a final impeller of the first plurality of impellers, a second shaft assembly disposed in the housing and rotatable about the longitudinal axis, the second shaft assembly including a second plurality of impellers, a first pair of annular seals between the final stage and an inner surface of the housing, the pair of annular seals being configured to permit relative rotation between the final stage and the housing, and a third annular seal positioned between the outer surface of the final stage and an inner surface of the second shaft assembly, the third annular seal configured to permit contra-rotation between the final stage and the second shaft assembly.

Abstract: A technique facilitates controlling barrier fluid via a mechanical pressure regulation system which may be coupled with a rotating machine at a subsea location. The mechanical pressure regulation system enables controlled supply of the barrier fluid to the rotating machine and comprises a mechanical valve mechanism. The mechanical valve mechanism automatically maintains a pressure differential between the barrier fluid and a process fluid within a desired range. According to an embodiment, the mechanical valve mechanism is mechanically actuated via pressures applied to a pilot piston so as to provide barrier fluid to the rotating machine when the pressure differential reaches a lower limit and to dump barrier fluid when the pressure differential reaches an upper limit.

Abstract: In rotating machine having a vertically oriented rotating shaft, a static magnetic force is used to simulate rotor weight and create the desired bearing preload. By installing a magnet the gravity based preload on the shaft journal bearings of a horizontal machine can be simulated for a vertical shaft. This can increase rotor stability, reduce the machine's vulnerability to hydraulically induced imbalance forces and give a more smooth transition through various shaft speeds.

Abstract: According to some embodiments, a subsea fluid processing system is described that includes a subsea electric motor that rotates a motor shaft about a central axis. A subsea fluid processing machine driven by a second shaft being rotated about the central axis. A subsea gear train system includes a plurality of gears positioned in one or more at least partially or fully oil-filled volumes. The plurality of gears are configured and arranged to transmit power from the first shaft to the second shaft wherein one revolution of the first shaft causes greater than one revolution of the second shaft. In some examples the gear form an epicyclic gear train arrangement.