T.D. Williamson SA (TDW) 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 a portion of the Burullus Gas Company’s West Delta Deep Marine (WDDM) Phase VII development project located in the Mediterranean Sea. Carried out on behalf of the Burullus Gas Company for Technip Norge AS, this operation required a tie-in of the new 36in gas export pipeline to an existing 26in gas export pipeline. TDW’s main task was to facilitate the tie-in program without halting production. In addition, an innovative 20in hot tap on the 36in line was performed on a blind weld-neck tappable flange comprised of duplex stainless steel. TDW carried out extensive engineering, design and preliminary testing at its facility in Nivelles, Belgium to prepare for the hot tap operations; a special hot tap tool referred to as a cutter was also developed to effectively cut the duplex plate for the operation.