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    TD Williamson completes hot tap intervention on pipeline

    Projects and Operations // May 31, 2011

    TD Williamson's divers work on the hot tap.

    TD Williamson SA (TDW) has announced that it has completed a subsea hot tap intervention operation to facilitate the successful tie-in of a new gas pipeline to an existing pipeline. 

    The new pipeline forms part of the Burullus Gas Company’s West Delta Deep Marine (WDDM) Phase VII development project in the Mediterranean Sea. 
    The operation was carried out for Technip Norge on behalf of the Burullus Gas Company, which required a tie-in of the new 36in gas export pipeline to an existing 26in gas export pipeline. 

    TDW’s primary objective was to facilitate the tie-in programme without shutting down production. 

    TDW completed two traditional 16in hot tap operations on the 26in gas export pipeline. In addition, an innovative 20in hot tap on the 36in line was executed on a blind weld-neck 'tappable flange' made of duplex stainless steel. 

    To prepare for the hot tap operations that would take place in depths to 95m, TDW carried out extensive engineering, design and preliminary testing at its facility in Nivelles, Belgium. 

    A special hot tap tool known as a cutter that would effectively cut the duplex plate was customized for the operation. This special cutter, which is more rigid than the standard tool, is vibration-free and features a specially manufactured removable cutting teeth system for use on specific duplex tools. 
    For approximately three weeks TDW worked from Technip’s dive support vessel Wellservicer to carry out all three hot taps. The innovative hot tap on the duplex tappable flange required just six days to complete. 

    Throughout the process, a prevailing pressure of 100 bar was successfully maintained in the 26-inch gas export pipeline.


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