Method for increasing subsea accumulator volume

Abstract

In a subsea system where subsea devices are operated using a pressurized fluid from one or more accumulators, the method of providing flow of pressurized fluid to operate a device which is greater than the flow from an accumulator providing the flow, comprising discharging the accumulator to drive one or more motors, driving one or more pumps by the one or more motors, the one or more pumps having a larger displacement than the one or more motors such that the one or more pump outputs a greater volume of fluid than the motor consumes, and delivering the output of the one or more pumps to operated the subsea device.

That which is claimed is: 
     
         1 . The method of providing a flow of pressurized fluid from a subsea accumulator to operate a subsea device, comprising:
 discharging the accumulator to drive one or more motors,   driving one or more variable displacement pumps by said one or more motors,   varying the displacement of said one or more pumps to provide a flow rate which is inversely proportionate to the pressure required to operate said subsea device.   
     
     
         2 . The method of  claim 1  further comprising said one or more pumps have variable displacement. 
     
     
         3 . The method of  claim 2 , further comprising said variable displacement of said variable displacement one or more pumps is generally a function of the inverse of the output pressure of said one or more pumps. 
     
     
         4 . The method of  claim 1 , further comprising said one or more motors is variable displacement. 
     
     
         5 . The method of  claim 4 , further comprising said variable displacement of said one or more variable displacement motors is generally an inverse function of the output pressure of said one or more motors. 
     
     
         6 . In a subsea system where subsea devices are operated using a pressurized fluid from one or more accumulators, the method of providing flow of pressurized fluid to operate a device which is greater than the flow from an accumulator providing said flow, comprising:
 discharging the accumulator to drive one or more motors,   driving one or more pumps by said one or more motors,   said one or more pumps having a larger displacement than said one or more motors such that said one or more pump outputs a greater volume of fluid than said motor consumes, and   delivering the output of said one or more pumps to operate said subsea device.   
     
     
         7 . The method of  claim 6  further comprising said one or more pumps have variable displacement. 
     
     
         8 . The method of  claim 7 , further comprising said variable displacement of said variable displacement one or more pumps is generally a function of the inverse of the output pressure of said one or more pumps. 
     
     
         9 . The method of  claim 6 , further comprising said one or more motors is variable displacement. 
     
     
         10 . The method of  claim 9 , further comprising said variable displacement of said one or more variable displacement motors if generally an inverse function of the output pressure of said one or more motors. 
     
     
         11 . In a subsea system for drilling oil and gas wells utilizing pressurized fluid as a power supply to accomplish tasks, comprising:
 storing said pressurized fluid at a first pressure and at a first volume,   using said first pressure and said first volume to generate a second larger volume than said first volume at a second pressure lower than said first pressure,   thereby increasing the volume available to do a desired task while maintaining said second pressure at a level high enough to do said desired task.   
     
     
         12 . The method of  claim 11  further comprising using said first pressure and volume to drive one or more motors to drive one or more pumps to generate said second pressure and volume 
     
     
         13 . The method of  claim 12 , further comprising said one or more pumps have variable displacement. 
     
     
         14 . The method of  claim 13 , further comprising said variable displacement of said variable displacement one or more pumps is generally a function of the inverse of the output pressure of said one or more pumps. 
     
     
         15 . The method of  claim 12 , further comprising said one or more of said one or more motors is variable displacement. 
     
     
         16 . The method of  claim 15 , further comprising said variable displacement of said one or more variable displacement motors if generally an inverse function of the output pressure of said one or more motors.