Considerations when lifting large module in different geographical areas

Master's thesis in Offshore technologyThrough the years in the oil and gas industry, the marine operations have been developing, and it continuous to develop. More production facilities offshore are under construction, and the activities offshore seem to increase rapidly. The operations done offshore are more advanced than ever and as a consequence of this, so does the marine operations, e.g. lifting operations. In this thesis, we will present several considerations when it comes to planning and performing a lifting operation. There are several factors to include in the planning and performing phase of a lift operation. Among them are waves, winds and currents, i.e. weather conditions. The weather conditions are also different in different geographical areas you are operating in. Another important factor is the vessel performing the operation. What is the capability of the vessel`s crane? How is the vessel availability? These questions will be discussed in the introduction below. This thesis will be concentrated on two specific areas, The North Sea and Offshore Angola. The reason for choosing these two areas is that they have two completely different sea states. The North Sea is mostly influenced by waves with higher significant heights and wave periods of around 8 to 10s, while offshore Angola has waves with shorter significant wave heights and periods of around 10s to 12s. In this thesis different sea states - , stability - , lifting – and simplified risk analyses will be presented. There will also be presented a simulation with the use of the software OrcaFlex