16” Multi-Set Isolation in the Black Hills

Client requested

Many of our projects involve providing isolation so buried valves can be brought above grade.  Below ground valves pose a greater integrity risk, and are often more difficult to service and maintain. 

Understanding the best solution

On this pipeline there was also a leaking launch valve, so the client requested the IsoTool’s multiset capability be utilized. 

Planning and delivery

.  The “A” Tool was launch out, and quickly achieved set.  The barrel was drained to sump, the old valve was swapped out and the new valve was installed and torqued up. 

The “B” Tool was loaded into the trap while the mechanical work took place.  The sump was pumped back in to fill the trap and the IsoTool technician opened the bypass to equalize. 

The “A” Tool was unset and Integral trackers followed the pigs overnight and parked them straddling a mainline valve. 

Both IsoTools we simultaneously set in less than an hour, and a small volume was drained up, since the valve was at a higher elevation then the IsoTools.  The new riser with valves was welded in, and the oil that was drained up was returned to the pipe. 

The internal bypasses in both tools were opened, and the pressure was equalized before the tools were unset.  The line was returned to Pipeline Control and the pigs were trapped separately and pulled.

Service completion report

By taking advantage of the IsoTool’s ability to perform up to 3 isolations before requiring servicing, 2 projects were completed in a single pig run and a short period of time. 

The client was pleased that they did not have to put full-bore tap fitting on the line, or have to deal with a nitrogen purge, and mentioned that the cost savings and outage reduction was noteable.