Collision Response Analysis During Spar Upper Module Installation

Now, along with our country’s increasing demand for oil and gas as well as our countryis carrying ocean exploitation stratagem into execution, exploitation for oceanic oil and gasin our country is developing into blue water district. Offshore hoisting is the last dangerengineering before the platform is put into use. Both of the motion of the upper moduleduring the lifting and the collision during the sitting are important facts for hoisting safety.Therefore, it is necessary to research the motion response and collision in the process ofhoisting.In this paper, the offshore hoisting of a Spar platform in South China Sea Liwan3-1gasfield is researched, the content focused on two aspects: analysis of the upper module couplingmotion with the crane and the collision during sitting. The major contents in this paper are asfollows:First of all, the installation scheme is chosen from synopsis of currently offshoreinstallation method, crane, installation technology parameter. At the same time, the keytechnology in construction is summerized.Then, crane and upper module coupling motion response differential equation isestablished by multi-rigid bodies dynamics, a numerical simulation of multi-rigid bodiesmotion response is processing by the AQWA software. The impact of different factors on thecoupling motion response is researched, including the upper module mass, the length oflifting wires and the lifting/sitting velocity. As the same time, a curve of resonance-proof isreceived.Lastly, on basis of explicit non-linear FEM, simplified upper module and Sparplatform’s collision FEA models are established referring to the old examples of simplifiedcollision FEA models, because of the possible collision between upper module and Sparplatform during the setting. The collision process in0.2m/s is analyzed by theANSYS/LS-DYNA software. Further, this paper analyzes that different initial velocities andangles impact on the von Mises stress and collision resultant force during the dockingcollision.This paper can provide reference for the upper module’s offshore hoisting schemedesign and practical construction, from contrasting the numerical simulation results of the parameters influent on multi-rigid bodies motion response and docking collision.