System and method for an automated subsea testing unit

Abstract

A system to test barrier pressure includes a Christmas Tree (XT) coupled to a wellbore including a downhole pressure barrier. The XT includes a first valve along a flow path and a second valve coupled to the flow path. The system further includes a testing unit that includes a vessel fluidly coupled to the flow path. The testing unit also includes a fluid mover associated with the vessel to draw fluid into or to drive fluid out of the vessel. The testing unit further includes an actuator coupled to the fluid mover to control operation of the fluid mover. The testing unit is configured to draw a volume of fluid out of the XT and to further return the volume of fluid to the XT.

1 . A system to test barrier pressure, comprising:
 a Christmas Tree (XT) coupled to a wellbore, the wellbore including a downhole pressure barrier, the XT comprising:
 a first valve along a flow path; and 
 a second valve coupled to the flow path; 
   a testing unit, comprising:
 a vessel fluidly coupled to the flow path, wherein the second valve is between the vessel and the first valve; 
 a fluid mover associated with the vessel to draw fluid into or to drive fluid out of the vessel; and 
 an actuator coupled to the fluid mover to control operation of the fluid mover; 
   wherein the testing unit is configured to draw a volume of fluid out of the XT in response to a command to perform a pressure test on the at least one pressure barrier, the testing unit to further return the volume of fluid to the XT after completion of the pressure test.   
     
     
         2 . The system of  claim 1 , wherein the fluid mover is a piston arranged within the vessel. 
     
     
         3 . The system of  claim 2 , wherein the actuator is an electrically driven rotary to linear motion device. 
     
     
         4 . The system of  claim 1 , wherein the pressure test is performed on at least one of the first valve or the downhole pressure barrier. 
     
     
         5 . The system of  claim 1 , further comprising:
 a third valve coupled to the flow path, the third valve being fluidly coupled to a fluid source for injecting a second fluid into the XT.   
     
     
         6 . The system of  claim 5 , wherein the fluid source is a carbon dioxide source. 
     
     
         7 . The system of  claim 1 , further comprising:
 a fourth valve positioned within a connecting flow path between the first valve and the second valve.   
     
     
         8 . The system of  claim 1 , wherein the testing unit is fluidly coupled to the XT via a hot stab. 
     
     
         9 . The system of  claim 1 , wherein the testing unit is directly coupled to the XT at one or more of a vent or a port. 
     
     
         10 . The system of  claim 1 , wherein the actuator is configured to be controlled by a subsea control system and the XT is a subsea XT. 
     
     
         11 . A method, comprising:
 determining one or more barriers for pressure testing;   operating one or more valves to isolate the one or more barriers;   causing a fluid mover to draw a quantity of fluid into a vessel;   conducting one or more pressure testing operations; and   causing the fluid mover to drive the quantity of fluid out of the vessel after completion of the one or more pressure testing operations.   
     
     
         12 . The method of  claim 11 , wherein the quantity of fluid is removed from a Christmas Tree (XT). 
     
     
         13 . The method of  claim 12 , further comprising:
 determining the quantity of fluid based, at least in part, on a differential pressure associated with the one or more barriers.   
     
     
         14 . The method of  claim 12 , wherein the quantity of fluid is returned to the XT after completion of the pressure testing. 
     
     
         15 . The method of  claim 11 , wherein the one or more barriers include at least one of a master valve or a downhole safety valve. 
     
     
         16 . The method of  claim 11 , wherein the pressure testing occurs in a subsea environment. 
     
     
         17 . A system to test barrier pressure, comprising:
 a well component including at least a first valve and a second valve arranged along a flow path, the flow path being coupled to a well;   a downhole pressure barrier positioned in the well;   a vessel fluidly coupled to the well component; and   a controllable fluid mover associated with the vessel, the controllable fluid mover configured to decrease a pressure within the vessel to draw a fluid into the vessel along the flow path and to increase a pressure within the vessel to drive the fluid out of the vessel along the flow path.   
     
     
         18 . The system of  claim 17 , wherein the well component is one or more of a Christmas Tree (XT), a manifold, a wellhead, or a combination thereof. 
     
     
         19 . The system of  claim 17 , further comprising:
 a third valve arranged along the flow path, the third value positioned to regulate an inlet flow, into the flow path, from a fluid source.   
     
     
         20 . The system of  claim 17 , wherein the fluid is a gas, liquid, solid, or a combination thereof.