Modeling the Dual Crane Lift of Maersk BD Module

McDermott Middle East, Inc. executed the Maersk Oil Qatar Project in 2009, Offshore Qatar. The project involved the installation of one of the heaviest lifts in the region — the 3283 MT BD Module. The deciding factor for the offshore installation methodology was the restriction on the lift capacity of the derrick barge. The execution strategy, therefore, involved utilizing two derrick barges, a semi-submersible and a mono hull barge, in tandem for the lift operation (Dual Lift). This paper discusses the engineering studies and the simulation model for a Dual Lift with insight into the technical complexities and the analytical strategy used for the study. On site adherence to the engineering analyses was achieved by a system of pre-installed motion sensors and instruments capable of delivering real time data of the key parameters required for the lift. The engineering and operations experience presented in this paper covers the Dual Lift operation with focusing on two main engineering aspects, the engineered lift study of BD Module and the multi-body mooring analysis compromising six floating bodies connected together by means of lashing and/or mooring lines.