Ball Valve Sub Flashcards
How does the BVS differ from the Dart Sub?
The BVS uses 4 ball valves that are used to redirect the pressure instead of Darts.
What is the purpose of the Ball Valve Sub?
It is used as a backup to the ROV Panel to redirect pressure from the drill string to set and test the RLSA
What advantages does the BVS have over the Dart Sub?
There is no need to drop darts which could get stuck and which also restrict the ID of the drill string. When finished with the BVS you can also open the 3” ball valve back up to prevent pulling a wet string. It also allows for the use of cement plugs to wipe the ID of the drill string.
What is the sequence for using the BVS to set and test the RLSA?
1 - close the 3” ball valve closing off the drill string below the tool
2 - open the 1” flush valve and flush the line, then close the flush valve
3 - open the 1” set valve and pressure up to 4,500 setting the RLSA
4 - close the 1” set valve
5 - open the 1” test valve and pressure up to 1,000 and hold for 2 minutes
6 - close the 1” test valve
7 - open the 3” ball valve to vent the system
How are the 1” ball valves plumbed to the ROV Panel?
One 1” valve is run to the DRT 1/2” Set port
One 1” valve is run to the DRT 3/8” Test port
How are the hoses compensated or filled when using the BVS?
The BVS doesn’t have compensation ports so the hoses need to be filled during pre-ops or at the rig floor prior to running subsea.
