摘要
自升式钻井平台在插桩、升船、预压载或降船作业等工况下,当遇到环境载荷过大、海底地质不佳等情况,会引起桩腿RPD(齿条相位差)值偏大,甚至有可能造成巨大的经济损失及人员伤亡.在介绍了RPD的定义、分类、计算原理、受力分析、测量方法、成因、超标危害等基础上,对某平台RPD超标进行详细的分析,描述了案例平台RPD设定值、定位插桩过程、桩腿受损调查、RPD值超标的原因分析、平台的修理等.最后指出,平台在定位插桩、升船、降船、预压载作业时应做好海调报告、地调报告、插桩压载方案、RPD超标风险控制预案等工作;平台插桩遇到"鸡蛋壳"地层时,压载作业应采用单桩多组压载或漂浮压载,做好存在穿刺风险的桩腿倾斜RPD超标、平台倾斜超标的应对措施.
Abstract
Excessive legrack phase difference(RPD)value of jack-up drilling platform can lead to huge losses and casualties,due to excessive environmental load and poor seabed geological conditions under the working conditions of pile insertion,jacking,pre-ballast or jacking down.Based on introducing the definition,classification,calculation principle,force analysis,measuring method,causes,and over-standard hazard of RPD,this paper analyzed the over-standard RPD of a platform in detail and illustrated RPD setting value,positioning and pile insertion process,leg damage investigation,cause analysis of over-standard RPD value,and repairment of a case platform.At last,it was pointed out that the marine investigationreport,geologic investigationreport,pile insertion,and ballast scheme,as well as RPD risk control plan should be done before the platform was in positioning and pile insertion operation,jacking,jacking down,or preloading.In the case of"egg-shell"formation,single leg and multiple ballast or floating ballast should be adopted in ballast operation.Besides,effective measuresshould betaken about punch-through risk caused by excessive leginclination RPD and excessive platform inclination.
NETL
NSTL
万方数据