T.D. Williamson (TDW), a global provider of pipeline equipment and services, announced completion of its first STOPPLE Train pipeline intervention program in the Republic of Georgia.
The isolations were performed on a major export pipeline that transports crude oil through a 522-mile section that extends from the Caspian Sea to the Black Sea. TDW was retained to isolate sections of the line to facilitate replacement of four pig trap isolation valves at two pressure reduction stations in the Georgian countryside.
The STOPPLE Train plugging system links two plugging heads into a “train,” which provides the added assurance of a double seal and bleed port at each isolation point. The linked plugging heads are simply inserted into the pipeline through a single opening. By doing so, one hot tap and fitting produce a double seal with capability to bleed the annulus created between the seals, creating a safe zone in between, without having to insert two separate isolation tools.
To make certain that the line would be successfully isolated, TDW custom-built a 21-inch, 102 bar (1480 psi) STOPPLE Train system. After the system was fully tested and rated, the 21-inch line was tapped. The STOPPLE Train system was then inserted at each of the four valve sites. This effectively created a barrier between work being performed downstream and the line’s internal pressurized contents. The affected sections of the pipeline were then bled down to 0 bar (0 psi) operating pressure.