OMAE, San Diego -- Rigs tied down with bolted friction clamps on floating production systems in the Gulf of Mexico did not prevent lateral movement in hurricanes. This is one of the findings of a study drafted by Skip Ward (Offshore Technology Research Center) and J.M. Gebara (Technip), said Gebara at OMAE in San Diego on Tuesday.
Rig clamps are used to prevent it from sliding on its host platform and for easy relocation. Data compiled for the study was taken from a review of deepwater platforms during past hurricanes. One bolt in clamp holding down the rig on Murphy-operatedMedusa spar sprung and tore from the rig skidding during a hurricane, Gebara said. The other clamp failure he pointed out was on Shell-operated Ram Powell TLP which revealed a skidding failure.
Gebara noted that some of the floating production systems that tied down their rigs with rack and pinion or hydraulic wedged pins faired well in hurricanes. The challenge ahead is in relying on clamps for preventing platform rig sliding and overturning, he concluded. Proper balance in bolt tension and friction in a clamp must be considered to mitigate risk of failure.