Natural gas pipeline intervention record in Australia

T.D. Williamson (TDW) has announced that it recently performed the highest ever STOPPLE® Train pipeline pressure intervention in company history in Australia. An operating pipeline pressure of approximately 1480 psi (102 bar) was maintained throughout the operation, which made it possible to safely remove and replace a natural gas pipeline valve in a remote desert in North West Australia.

Production flows, safety enhanced

TDW was retained to use the STOPPLE Train intervention method for a number of reasons. The operator wanted to make certain that the affected section of the pipeline could be tapped, plugged and safely isolated without shutting it down, which would have resulted in a halt in production. This method uses field-proven plugging technology to temporarily block sections of live pipelines. It is the only system of its kind that links two plugging heads to form a ‘train’ that effectively provides double-block and bleed isolation. With its double-block and bleed design, it is possible to insert two plugging heads through a single fitting. This method is preferable because it allows a technician to install two barrier surfaces (including a bleed port for pressure and product evacuation) between work (such as welding or pipe cutting) being performed downstream and the line’s internal pressurised contents.

Prior to the operation, TDW custom-built a fully-rated 1480 psi (102 bar) STOPPLE Train system at its manufacturing plant in Tulsa, Oklahoma. Following a program of rigorous testing of the system to make certain that the job could be completed through the spool and fittings, Technicians travelled through the desert to the remote compressor station. Working in the early morning hours to avoid the 95 °F (35 °C) mid-day heat, the TDW team used a pressure-balanced tapping machine to hot tap the 16 in. pipeline, and the specially-engineered STOPPLE Train system to plug it. For two days, the affected section of the pipeline was isolated while the valve was replaced and production flowed. The entire operation – including set-up, hot tapping, STOPPLE Train plugging, valve replacement, and setting the LOCK-O-RING® completion plug – was completed in just seven days.

“By using the STOPPLE Train plugging method to isolate the pipeline, the customer was able to pack the pipeline and continue to supply to its downstream customers, without having to depressurise a substantial amount of the pipeline, and incur the cost of a considerable amount of lost natural gas,” said Joe Buttigieg, Global Hot Tap & Plugging Technical Specialist for TDW. “In addition, because the system requires just one STOPPLE fitting instead of two, it meant that fewer fittings were required and, therefore, less excavation, non-destructive testing, and hydrotesting. Associated costs with these were effectively reduced by 50%,” he added.

Pipeline interventions on the rise

To date, TDW has carried out STOPPLE Train intervention operations for nearly every major operator in the US. In 2010, the company began to offer this service globally. Since then, TDW has carried out successful STOPPLE Train interventions in Italy, Belgium, Kazakhstan, and, most recently, Australia.

Adapted from press release by Cecilia Rehn

Read the article online at: https://www.worldpipelines.com/business-news/01082013/natural_gas_pipeline_intervention_record_in_australia/