STATS were required to isolate a 38” gas pipeline using a Remote Tecno Plug™ to facilitate the removal of a corroded 2” bypass branch connected to a 38” ESDV. The pipeline STATS isolated was operating at 85 barg and produced a gas service with 0.7% concentration of H2S. Prior to pigging the Remote Tecno Plug™ to position, a 38” high differential Bi-Di pig was deployed a distance of 1km to provide a water barrier between the Remote Tecno Plug™ and the pipeline gas.
During pigging operations the Tecno Plug™ position was tracked and confirmed using STATS extremely low frequency through-wall communication system. With the isolation confirmed, the operator then carried out the maintenance to remove and blind the 2” branch from the 38” ESDV. Before the Tecno Plug™ was unset and removed from the pipeline, the client required a pressure test of the modified line to confirm integrity. This was achieved by equalising the pipeline and receiver side pressures to 90barg while the Tecno Plug remained in a fully ‘set’ condition. This reverse pressure test operation created a 90 barg test boundary to confirm the newly installed weld. With the maintenance successfully completed the Remote Tecno Plug™ and Bi-Di pig were reverse pigged back to the launcher and demobilised.
This successful project provided a safe and cost effective double block and bleed isolation, resulting in no interruption to plant production and preventing a costly shutdown. The safe and efficient workscope was a result of advanced planning, dedication and team work between STATS and client personnel.
Gas pipeline isolation facilitates removal of 2” bypass branch connected to a 38” ESDV