Comparison study of jack-up drilling unit's dynamic behaviour

Abstract

Jack-up is one of the most excellent drilling rigs in offshore oilfield in water depth shallower than 150 m. As the most critical component of jack-up drilling unit, the leg system will affect the global performance of the platform significantly. This paper mainly deals with the dynamic analysis of a jack-up unit leg system. Analysis of three frequently used truss-type legs is conducted including X-type, reverse (rev) K-type and mixing type. In this study, detailed models are built to simulate the jack-up unit. Multi-point constraint (MPC) elements are used together with the spring elements to deal with the boundary condition. Static response analysis, dynamic response and weight, which are the key technical objects of jack-up legs are analysed and compared for three kinds of different leg through finite element analysis.

Keywords:

• jack-up unit
• leg structure form
• reverse K-type leg
• X-type
• mixing type
• multi-point constraint (MPC)
• key performance target