Effect of moorings drag and inertia on response of spar platform

Abstract

Spar platform is a type of floating structure utilized for oil and gas exploration and production in deep and ultra-deep waters. Coupled analysis in present study considers Spar mooring lines as an integrated system. It incorporates the contribution of drag and inertia forces of mooring lines. A rigid classical Spar cylinder connected by four tensioned catenary mooring lines has been modeled and analysed using finite element approach. Mooring system has been modeled as hybrid beam elements. The Studies cover surge, heave, pitch and mooring line tension responses, highlighting the coupling effect. The non-linearities present in the coupled system leads to irregular behavior under regular sea states. The coupled model noticeably confirms its importance in terms of hydrodynamic damping on mooring system. There is a key variance in behavior found with and without drag and inertia forces on mooring system.