System and method for delivering material to a subsea well

Abstract

A system and method for delivering a material from a vessel at a surface facility to a subsea location and into a subsea well are provided. The system generally includes a first-stage pump that is located at the surface facility and is configured to receive the material from the vessel. A tubular member extends from the first-stage pump to the subsea location. A second-stage pump is located at the subsea location and connected to the tubular member. The first-stage pump is configured to deliver the material through the tubular member to the second-stage pump at a first pressure, and the second-stage pump being configured to receive the material from the tubular member and inject the material into the well at a second pressure higher than the first pressure.

What is claimed is: 
     
         1 . A system for delivering a material from a vessel at a surface facility to a subsea location and into a subsea well, the system comprising:
 a first-stage pump located at the surface facility and configured to receive the material from the vessel;   a tubular member extending from the first-stage pump to the subsea location; and   a second-stage pump at the subsea location and connected to the tubular member, the first-stage pump being configured to deliver the material through the tubular member to the second-stage pump at a first pressure, and the second-stage pump being configured to receive the material from the tubular member and inject the material into the well at a second pressure higher than the first pressure.   
     
     
         2 . A system according to  claim 1  wherein the tubular member is a flexible umbilical, the umbilical defining a first tubular passage for receiving and delivering the material, and a second tubular passage having at least one conductive cable for communicating between the surface facility and the subsea location. 
     
     
         3 . A system according to  claim 2  wherein the conductive cable is configured to provide at least one of an electrical signal for controlling the operation of the second-stage pump and electrical power for powering the operation of the second-stage pump. 
     
     
         4 . A system according to  claim 1  wherein the second-stage pump is disposed on the seafloor. 
     
     
         5 . A system according to  claim 1  wherein the second-stage pump is disposed as part of a tree at a head of the subsea well. 
     
     
         6 . A system according to  claim 1  wherein the vessel is configured to provide a scale squeeze treatment chemical adapted to inhibit scaling and the second-stage pump is configured to inject the chemical into the well to perform a scale squeeze treatment of the well. 
     
     
         7 . A system according to  claim 1  wherein the tubular member is a flexible tube formed of a thermoplastic material. 
     
     
         8 . A method of delivering a material from a vessel at a surface facility to a subsea location and into a subsea well, the method comprising:
 operating a first-stage pump located at the surface facility to pump the material from the vessel through a tubular member extending from the first-stage pump to the subsea location; and   operating a second-stage pump at the subsea location and connected to the tubular member to inject the material from the tubular member into the well.   
     
     
         9 . A method according to  claim 8 , further comprising providing a flexible umbilical as the tubular member, wherein operating the first-stage pump comprises pumping the material through a first tubular passage of the umbilical, and further comprising providing at least one conductive cable in the umbilical in communication with the surface facility and the subsea location. 
     
     
         10 . A method according to  claim 9 , further comprising communicating an electrical signal from the surface facility to the subsea location via the conductive cable to control the operation of the second-stage pump. 
     
     
         11 . A method according to  claim 9 , further comprising providing electrical power from the surface facility to the subsea location via the electrically conductive cable to power the operation of the second-stage pump. 
     
     
         12 . A method according to  claim 8  wherein operating the first-stage pump comprises providing the material to the tubular member at a pressure that is greater than a pressure drop that occurs through the tubular member and less than a sum of the pressure drop that occurs through the tubular member and a pressure required for injecting the material into the well. 
     
     
         13 . A method according to  claim 8 , further comprising providing the second-stage pump at the seafloor. 
     
     
         14 . A method according to  claim 8 , further comprising providing the second-stage pump as part of a tree at a head of the subsea well. 
     
     
         15 . A method according to  claim 8  wherein operating the first-stage pump and the second-stage pump comprises injecting a scale squeeze treatment chemical into the well to thereby perform a scale squeeze treatment of the well and inhibit scaling in the well. 
     
     
         16 . A method according to  claim 8 , further comprising providing a flexible tube as the tubular member, the flexible tube being formed of a thermoplastic material.