An innovative rig repowering collaborative between Wartsila NSD
and Houston Ship Repair, Inc. was recently completed in the U.S. Gulf, involving the installation of new gensets on Semisubmersible Drilling Rig Transocean Amirante of Transocean Sedco Forex. The upgraded Semi, now installed with more than 8.0 generation capacity, was conceptualized in late 1998.
The work required extreme flexibility in scheduling, and included the possibility of a quay side or offshore installation. The project commenced with the carrying-out of a joint on-board survey, and was followed by meetings with Transocean, Wartsila NSD and HSR to specify responsibilities and detailed planning for a successful project.
The existing units were replaced by four Wartsila 12V200 generator sets, rated at 2,100 bKw at 1,200 rpm. Houston Ship Repair carried out the yard work in Mobile, Ala., and mechanical and electrical engineering of auxiliary systems.
To minimize downtime, installation was carried out in three phases; the first two being the change-out of exhaust pipes and silencers and upgrading electrical components such as transformers.
Major work commenced late in 1999 and was completed in five weeks. The third phase involved:
· Removing the old units, redundant piping and equipment;
· Making suitable foundation modifications;
· Installing new common bases, engines and alternators;
· Installing new equipment and piping;
· Installing new power cables, control cables, AVRs, control systems, digital governors and rewiring of some existing electrical and controls systems.