The mooring and riser system is the most critical part of an ofshore oil terminal.Traditionally,these two parts are designed separately without considering the nonlinear interaction between them.Thus,the present paper...The mooring and riser system is the most critical part of an ofshore oil terminal.Traditionally,these two parts are designed separately without considering the nonlinear interaction between them.Thus,the present paper aims to develop an inte-grated design process for riser systems with a lazy-S confguration and mooring systems in the ofshore catenary anchor leg mooring(CALM)oil terminal.One of the important criteria considered in this integrated design is the ofset diagram and safe operation zone(SAFOP)related to the mooring system and the riser,respectively.These two diagrams are obtained separately by diferent analyses;therefore,codes or standards are available separately for two components.In this methodol-ogy,the diagrams of both risers and mooring lines are incorporated into a single spiral,thus identifying the safe and failure zones of risers and the mooring lines of the oil terminal.This,in turn,leads to substantial benefts in terms of overall system response,cost reduction,and safety to the ofshore oil terminal.To implement this process,three diferent riser lengths with the lazy-S confguration are considered at three diferent sea depths at the terminal installation site.For each condition,the integrated design of the mooring system and riser is executed according to the derived procedure.Then,coupled dynamic models,wherein both buoys and hoses are included,are developed using OrcaFlex.Results show that the criteria of the relevant regulations are not satisfed by reducing the length of the riser relative to the designed size.Further,as water depth increases,this type of riser confguration shows good coupled performance while interacting with the mooring system.In the cross ofset mode,the maximum margin is created between the ofset diagram and the SAFOP diagram,while the most critical dynamic response of the tanker and terminal system occurs in the near and far modes.Therefore,with this method,the best position for the riser direction with the tanker direction is 90°in the best case.展开更多
文摘The mooring and riser system is the most critical part of an ofshore oil terminal.Traditionally,these two parts are designed separately without considering the nonlinear interaction between them.Thus,the present paper aims to develop an inte-grated design process for riser systems with a lazy-S confguration and mooring systems in the ofshore catenary anchor leg mooring(CALM)oil terminal.One of the important criteria considered in this integrated design is the ofset diagram and safe operation zone(SAFOP)related to the mooring system and the riser,respectively.These two diagrams are obtained separately by diferent analyses;therefore,codes or standards are available separately for two components.In this methodol-ogy,the diagrams of both risers and mooring lines are incorporated into a single spiral,thus identifying the safe and failure zones of risers and the mooring lines of the oil terminal.This,in turn,leads to substantial benefts in terms of overall system response,cost reduction,and safety to the ofshore oil terminal.To implement this process,three diferent riser lengths with the lazy-S confguration are considered at three diferent sea depths at the terminal installation site.For each condition,the integrated design of the mooring system and riser is executed according to the derived procedure.Then,coupled dynamic models,wherein both buoys and hoses are included,are developed using OrcaFlex.Results show that the criteria of the relevant regulations are not satisfed by reducing the length of the riser relative to the designed size.Further,as water depth increases,this type of riser confguration shows good coupled performance while interacting with the mooring system.In the cross ofset mode,the maximum margin is created between the ofset diagram and the SAFOP diagram,while the most critical dynamic response of the tanker and terminal system occurs in the near and far modes.Therefore,with this method,the best position for the riser direction with the tanker direction is 90°in the best case.
