TDW Offshore Services (TDW) announced another successful pipeline intervention using the SmartPlug pressure isolation tool. This operation, which was carried out for Talisman Malaysia Limited, allowed the safe replacement of a shutdown valve (SDV) on a key section of a gas export pipeline without having to bleed down the line. This allowed Talisman to avoid a costly production shutdown to replace the valve. The operations were carried out on a 24-inch pipeline extending between two platforms located off the coast of Peninsular Malaysia.
Solution: safe isolation of pipeline pressure
When it became apparent the SDV required replacement, Talisman contacted TDW to help them replace the valve as quickly as possible, without disrupting production. TDW formulated a solution that involved using a triple module 24-inch SmartPlug pressure isolation tool to create a double-block isolation against the gas pressure in the affected section, and to perform the post-valve replacement pressure test. After the pipeline was isolated, the isolated section would be depressurized, allowing the SDV to be replaced.
To execute the double-block pressure isolation, the SmartPlug tool was launched and pigged with nitrogen for approximately 20 meters past the valve and into the riser. TDW offshore specialists then set the SmartPlug tool vertically in the riser. The SmartTrack™ system, which uses proprietary electromagnetic and Extremely Low Frequency (ELF) signaling technology, made it possible to track the SmartPlug tool as it traveled along the pigging route, and to monitor pressure throughout the entire operation.
For 11 days, the SmartPlug tool remained in the line, creating a double-block isolation. Pipeline pressure was maintained at 90 bar while Talisman replaced the valve. After the valve was replaced, TDW specialists set the third module of the SmartPlug tool so that a test on the new valve against an operating pressure of 99 bar could be performed. The SmartPlug tool was then unset and pigged back using gas pressure from the pipeline. From mobilization to demobilization, the entire operation was completed in 16 days. Using this technology, Talisman was able to isolate their pipeline and replace the valve, efficiently and safely.
The pressure isolation operation was carried out by TDW personnel based in Stavanger, Norway, and Singapore, and an independent engineering agent of TDW in Malaysia.
This is not the first pressure isolation operation carried out by TDW for Talisman Malaysia. In 2006, TDW performed a pressure isolation operation on the same pipeline and riser attached to the platform in order to facilitate safe installation of an adjacent riser. TDW specialists launched the SmartPlug isolation tool, and pigged it with gas through the riser into the horizontal section of the pipeline on the seabed for approximately 300 meters.
Talisman retains TDW to supply pigs and pigging services
In related news, Talisman Malaysia recently entered into a Master Service Agreement with TDW for the provision of pigging assessment services, pigs, and training in the operation of special pigs, such as the V-Jet® spray pig. The multi-year agreement ensures that Talisman’s pigs are maintained and its pig inventory is properly stocked with the appropriate type of pigs, including bi-directional pigs, foam pigs and special application pigs. To ensure that Talisman is properly supported, TDW maintains Talisman’s spare pig inventory at its facility in Singapore so necessary supplies can be transported promptly. TDW also provides expertise in pigging and feasibility studies, as required.
“With the completion of this recent isolation operation and the new Master Service Agreement for pigging supplies and services, our relationship with Talisman continues to grow,” said Rolf Gunnar Lie, Regional Business Development Manager for TDW in Singapore. “That we continue to work consistently for Talisman and other operators in the region is a reflection of the solid, long-term relationships we have cultivated over the years. It’s what business is all about,” he added.