SIANJIA FLOW CONTROL

Gas Valve Upgrade Project on Deepwater Pipeline Network Carried Out Safely While Hydrocarbon Pressure

Author：CVVT.SIANJIA FLOW CONTROL PublicTime：2014-11-13 Views：2130

Oil and gas activity in the Gulf of Mexico remains high, as does the commitment to operational and process safety. Every procedure involving a pipeline, platform or asset is closely scrutinized, which means pipeline operators are under considerable pressure to meticulously maintain their networks by regulatory bodies. This being so, increasingly efficient valve replacement has become a top priority. Executing a valve upgrade program is a complex operation, in and of itself, as it must be completed safely, with minimal disruption to production. However, additional care must be taken to ensure that the sections of pipeline in need of new valves are securely isolated from pressure in the pipeline so that they can be safely replaced.
 
When a major operator set out to execute a gas valve upgrade project on a deepwater gas export pipeline offshore New Orleans in the Gulf of Mexico, it turned to pipeline services specialist T.D. Williamson (TDW). Working in a strategic partnership with this operator, TDW provides pipeline pressure isolation services under the terms of a global pipeline isolation and intervention services contract entered into in 2012. TDW uses its remote-controlled SmartPlug® tool to isolate pressure in specific sections of pipelines and risers so that repairs or interventions can be carried out safely.
 
Initially, TDW was required to isolate a 16-inch gas riser connected to a major subsea gas pipeline network in order to replace a valve, so it carried out engineering work, assembled the pressure isolation tool, and completed all factory acceptance testing (FAT) in mid-2012. Plans changed when the operator decided to postpone replacement of the single valve so that three additional valves could be installed, and a launcher extension added to facilitate inline inspection tool runs. In the event that the original valve did not meet the regulatory function requirements, TDW shipped the SmartPlug tool and FAT rig to Houston where they remained on stand-by for a rapid response during this interim period. In early 2014, TDW was advised that the planned isolation would commence in May 2014.
 
To ensure that this high profile isolation operation would go to plan and achieve first-time run success, TDW re-verified the project engineering, performed additional communication and pull tests, and executed a new in-depth FAT. In addition, a comprehensive range of risk and peer reviews internally and with the client were carried out. Working in cooperation with the operator’s team, 3,500 hours were invested in preparing for the isolation.


Reducing risk, protecting people

When the teams mobilized to the platform, they were fully prepared to execute the isolation. With personnel safety as the top priority, all non-essentials were transferred from the platform during the launch and setting of the SmartPlug isolation tool. With only essential personnel working on the platform, the SmartPlug tool was pigged for 18.28m (60 ft.) into the riser toward its set location. TDW used its remote-controlled SmartTrack™ tracking and monitoring system to track the tool’s progress, control its speed, and monitor conditions in real-time. Upon reaching its set location, the tool was set into position. By 11 p.m. that night, the isolation was confirmed and certified. The riser was securely isolated against a pressure of 118 bar (1711 psi) for 79 days. During this 11-week period, the three valves were replaced and the launcher extension installed, which would greatly enhance future inline inspections of the line. Upon completion of these tasks, the SmartPlug tool was safely retrieved.
 
“Because we worked in such close cooperation with this strategic partner, we developed an extremely high level of communication and understanding, which was essential to making the isolation a first-time run success,” said Bjørn-Olav Gilje, Project Manager for TDW. “As a result, the complex valve upgrade project and launcher extension installation were completed with minimal downtime, without disrupting production or supply to millions living on the Gulf Coast. A continuous flow through the multiple downstream connections was maintained throughout the duration of the project. The fact that it was achieved safely, without affecting the surrounding environment in any way makes it all the more satisfying,” he added.
 
For TDW, this high-profile operation represents a milestone in terms of preparation, dedication to the highest levels of safe working practices, and teamwork, as reflected by the company’s participation in the numerous workshops hosted by the operator for all contractors involved in the project. The recent pipeline isolation executed in the Gulf of Mexico illustrates the many benefits of the SmartPlug pipeline pressure isolation method, and how it offers a cost-effective, reliable method of executing maintenance and upgrade works, safely and efficiently, with minimal - or no - impact upon production and the interests of downstream operators.