STATS Group deployed a custom-designed 56-inch Tethered Tecno Plug to replace a scraper trap valve, while ensuring safety and compliance through rigorous testing and monitoring

STATS Group has successfully completed a 56-inch inline isolation of a crude oil pipeline in Saudi Arabia to enable a scraper trap valve replacement without halting production.

A major client in Saudi Arabia required the replacement of a 56-inch scraper trap valve, with the critical condition that the work be completed without shutting down, purging, or flushing the entire pipeline.

STATS was approached to engineer a solution whereby an isolation tool could be deployed to allow the safe replacement of the scraper trap valve.

Following a comprehensive engineering study and detailed site survey, STATS proposed a custom-designed 56-inch Tethered Tecno Plug®, tailored specifically for this application and to overcome challenges with some non-standard scraper trap features.

Jijo George, Middle East - Manager of Projects at STATS Group, says: "This is the largest Tecno Plug in the history of STATS, highlighting a remarkable milestone in our capability to deliver safe, innovative and large-scale isolation solutions for critical pipeline infrastructure."

He adds: "This successful project provided a safe and cost-effective double block isolation, resulting in no interruption to production and preventing a costly shutdown. The safe and efficient workscope was a result of advanced planning, dedication and teamwork between STATS and client personnel."

STATS Tethered Tecno Plug isolation system featured two integrated isolation modules, engineered to deliver a safe and controlled pipeline isolation.

56-inch Tethered Tecno Plug and Door Plug deployment

The first module, known as the Door Plug, replaces the scraper trap door and provides the primary isolation.

Once primary isolation is confirmed, the second module — The Tecno Plug — is advanced to its designated set location immediately downstream of the 56-inch scraper trap receiver valve.

Both modules are designed to deliver a fail-safe double block and monitored isolation.

Each isolation plug features dual elastomer seals and taper locks, the annulus void between the seals can be pressure tested to confirm seal integrity before breaking containment.

The inline isolation tool is DNV Type Approved and fully certified ensuring compliance with the highest industry standards.

RIGOROUS TESTING & DEPLOYMENT

Prior to mobilisation, a comprehensive Factory Acceptance Test (FAT) was carried out on all 56-inch equipment at STATS’ Abu Dhabi facility.

The test replicated site conditions and validated equipment performance under maximum isolation pressure.

To further ensure integrity, an additional leak test was conducted at STATS’ Dammam facility before final deployment at site.

Both test phases were witnessed by client representatives, ensuring full alignment to stringent operational and safety standards.

Following thorough pre-deployment inspections, the deployment tray holding the isolation plugs was positioned in front of the pipeline scraper trap door.

The client then depressurised the scraper trap and opened the door, enabling safe loading of the 56-inch Tethered Tecno Plug and Door Plug.

Using stem bars, both the isolation plugs were pushed on wheels into the scraper trap and advanced into the pipeline until the front isolation plug was in the minor barrel.

Pipeline isolated and valve removed

Once in position, the rear Door Plug was hydraulically activated, causing the taper locks and dual seals to radially expand against the pipe wall.

Seal testing was performed to verify the integrity of the primary and secondary seals, with both seals independently tested and monitored.

The Door Plug replaces the scraper trap door and allows access for the tether (Hydraulic control and monitoring lines) to pass through, enabling the pipeline to remain pressurised and operational, without replacing or modifying the original scraper trap door.

After confirming the double block isolation, a leak-test of the scraper trap was performed and the 56-inch scraper trap valve was opened, allowing the Tethered Tecno Plug to be pushed downstream of the valve location.

The compact design of the Tethered Tecno Plug allowed the isolation plug to be set in the short section of pipework upstream of the production tee maintaining uninterrupted production.

With primary and secondary seal tests completed and double block isolation verified, the isolation certificate was issued and the client unbolted the existing scraper trap valve. The stem bar was hydraulically disconnected, allowing removal of the old valve.

During valve replacement operations, a remote monitoring module maintained continuous surveillance of the dual seals, relaying pressure readings in real time back to the STATS isolation technician.

The Tecno Plug and Door Plug remained leak-tight and stable under monitored conditions throughout the remedial works, effectively isolating downstream pressure (55 bar) without halting production.

Following installation of the new 56-inch scraper trap valve, the stem bar was reconnected hydraulically and the valve fully torqued. Communication systems were verified, and a flange joint leak test was conducted.

Upon successful testing, the Tecno Plug isolation certificate was withdrawn, and pipeline product was reintroduced into the section between the Tecno Plug and the Door Plug to equalise pressure and prepare for the isolation plug removal sequence.

The Tecno Plug was then unset and retracted to its initial deployment position. After closing the new scraper trap valve, a pressure build-up test was performed to confirm valve integrity.

Finally, the Door Plug was unset and both the Tecno Plug and Door Plug were retracted to the original deployment tray, marking the successful completion of the operation.