Hareket used four Terex CC 2800-1 crawler cranes to lift and move a 1,241 tonne drilling support module (DSM) in Baku, Azerbaijan. IC reports
Turkey-based crane service company Hareket carried out the work for Amec-Tekfen-Azfen Consortium's West Chirag oil platform (WC-PDQ), part of the Chirag Oil Project.
The drilling support module is the platform's heaviest component. It was lifted 18 m and moved a distance of 51 m, meaning the four cranes had to operate at up to 95% of their lifting capacity. This posed a daunting challenge to machinery and personnel, said Bob Parker, the Amec project manager. "The fact that there were already two CC 2800-1 units being used for assembly work at the drilling platform was yet another good reason to order two additional cranes of the same type for the four-crane lift."
Two of the four units were delivered by DAS Otomotiv, authorised distributor for Terex in Turkey and Azerbaijan and in charge of training Hareket's team for assignments involving the 600 tonne capacity CC 2800-1.
The team spent eight days configuring the cranes, preparing the ground and carrying out the lift. The lift was so ambitious that leveling the ground and ensuring it could support the pressure of the cranes took two days: "In order to make paths that would be sufficiently strong for the cranes, we had to bring in large amounts of fill material on trucks and compact it with road rollers and vibratory plate compactors, which our team did for a full twelve hours each day," explained Bob Parker, BP Heavylift superintendent.
The weather proved problematic too. The lift could not be performed safely unless the wind speeds in the area fell below 8 m/s and the team had to wait two days before meteorologists forecasted a six-hour window for these conditions.
The four CC 2800-1 cranes were set up identically with an SSL configuration, a 60 m main boom and 400 tonnes of counterweight, with one difference: two of the cranes had a Superlift counterweight of 300 tonnes, while the other two had a Superlift counterweight of 250 tonnes.
"The DSM's centre of gravity was not centered, as the module was heavier on one side than on the other," explained a Terex spokesman. "In order to effectively counter this imbalance, the two cranes on the lighter side worked with a smaller counterweight and a steeper boom angle, meaning that they also worked with a smaller radius."
As an additional measure, the team adjusted the pad-eyes on the DSM to prevent it from being skewed in one direction. The cranes were then prepared to lift the 28 m tall module, with a base area of 21 by 19 m. The team kept the load transfer well under the maximum permissible limit of 12 tonnes, at under 3 tonnes for the entire operation.