All Electric Subsea Boosting System

Abstract

The present invention relates to an all electric subsea boosting system for well fluid boosting by compressing hydrocarbon gases and/or pumping hydrocarbon liquids where said system comprises one or more subsea boosting stations and one or more long step-out power supplies.

1 - 12 . (canceled) 
   
   
       13 . A subsea boosting system for a subsea installation, for boosting well fluid pressure when compressing hydrocarbon gasses and pumping hydrocarbon liquids, said system comprising at least one long step-out power supply and at least one subsea boosting station, each boosting station comprising at least one separator for separating gas and liquid phases, at least one gas compressor and at least one liquid pump, both arranged after said separator, the system further comprising inlet and outlet Manifolds and at least one high voltage electric system, and each long step-out power supply terminating in a power umbilical termination head attached to a main transformer in a boosting station, said system being characterized in that each subsea boosting station further comprises electrically actuated valves, an all electric utility power system and an all electric control system. 
   
   
       14 . The system of  claim 13 , characterized in that at least one of said subsea boosting stations further comprises circuit breaker modules and a barrier system. 
   
   
       15 . The system of  claim 14 , characterized in that said at least one subsea boosting station further comprises at least one inlet cooler and an inlet sand trap. 
   
   
       16 . The system of  claim 13 , characterized in that said at least one subsea boosting station comprises at least one compressor module, at least one compressor VSD, at least one anti-surge valve and actuator, at least one anti-surge cooler, at least one separator and/or scrubber module, at least one pump module, at least one pump VSD, remotely and manually operated valves, interconnection piping and control system including control modules. 
   
   
       17 . The system of  claim 13 , characterized in that each long step-out power supply comprises a subsea main transformer with pressure compensation system, high voltage penetrators, an umbilical termination head and a power and control umbilical including main electrical supply, utility power, and fibre optic lines for control signals. 
   
   
       18 . The system of  claim 16 , characterized in that each compressor module comprises at least one compressor which is directly driven by a variable speed controlled (=VSD) high-speed electric motor with magnetic bearings, said motor being cooled by hydrocarbon gas. 
   
   
       19 . The system of  claim 16 , characterized in that said anti-surge cooler is designed for heat transfer by convection with the sea water. 
   
   
       20 . The system of  claim 16 , characterized in that said separator and/or scrubber module is designed to absorb liquid slugs, ensure sufficient gas and liquid levels for safe operation of compressor and pump modules by level control, and prevention of internal solid buildups by possible re-circulation of liquid. 
   
   
       21 . The system of  claim 16 , characterized in that said liquid pump(s) is designed to be solid tolerant and can be operated either with variable speed by means of a variable speed drive or operated on fixed speed with control of discharge flow and pressure by a regulating valve, said valve discharging liquid back to the separator/scrubber module. 
   
   
       22 . The system of  claim 21 , characterized in that said liquid pump(s) is designed with an electrical motor cooled by hydrocarbon gas or a liquid. 
   
   
       23 . The system of  claim 18 , characterized in that said control system including control modules is designed for control and monitoring of at least one subsea compression train, further for control of all other functions on the boosting station, and to include direct communication with a receiving facility and any local closed loop required to operate the boosting station in a safe and operational friendly manner.