EnerMech has completed a slew bearing replacement on the North Crane on BP Azerbaijan Exploration’s Chirag 1 platform in Baku.
The mechanical engineering group completed the £500 000 project, including design, build, testing and installation, in less than three months.
Working with BP Baku’s structural team
EnerMech has a long-standing relationship with BP Azerbaijan, providing offshore crane operation, maintenance and inspection services to all of its Caspian platform assets and the Shah Deniz gas development.
Working closely with BP Baku’s structural team, EnerMech designed a crane-specific jacking frame and following a successful FAT test at EnerMech’s Baku yard, all equipment and materials was shipped offshore to meet the tight completion schedule.
The first challenge was to align the jacking frame legs with the pedestal of the crane. Four jacking pads were welded directly onto the pedestal and the underside of the crane chassis and a habitat was built around the frame so that welding could begin.
After the successful completion and MPI of the welds, the final assembly of the jacking frame was constructed with 4x75 t hydraulic jacks placed in to the jacking frame legs. The jacking structure was overload tested to ensure the integrity of the welds and bolts. Once this was successfully completed the 56 t crane chassis was lifting to a height of 500 mm.
The pedestal face and the underside of the crane chassis were checked by lasers for flatness and with readings confirmed as within the acceptable tolerances for the new slew bearing, no machining was required.
The new slew bearing was pulled onto the pedestal of the crane, ensuring that the ‘soft spot’ of the bearing was positioned 90° to the load path of the crane. In a reverse procedure of the jacking operation, the crane chassis was slowly lowered down onto the new bearing, new slew bolts were inserted and torqued to the OEM specifications.
EnerMech Cranes & Lifting Director, John Morrison commented: “After the final commissioning checks, the crane was proof load tested and returned to service. This scope of work was completed safely, on time and on budget, and was a real success for a project of this complexity.”
Adapted from press release by Cecilia Rehn