Offshore transport and installation simulation for process planning

Abstract

The ocean covers approximately 72% of the planets surface, and 80% of Earths species sustain their lives in the ocean. Ocean supplies not living resources alone but non-living resources: fossil, renewable energy and mineral resources. In this reason, the future prosperity of humanity depends on marine development. Today, about 30% of crude oil is produced from the offshore oil field. The offshore share is increasing gradually because of the advances in exploration technology. Furthermore, the ocean is a huge renewable energy supplier, such as wind, tidal, wave and thermal difference energy. The development of renewable energy has a drawback of low energy efficiency. Nevertheless, related technology is facilitated under the series of the global climatic change convention such as United Nations Framework Convention on Climate Change (UNFCCC), Kyoto Protocol and Paris Agreement. Fixed or floating typed offshore platform is necessary to develop ocean resources. Such platforms are constructed at the coast shipyard and towed to the installation site. The offshore platform requires extra processes such as the construction of the foundation, offshore transportation, installation of the mooring line and submarine cable. This transportation and installation (T&I) process charges 10 to 20% of total project cost and can affect the design and construction process. The T&I process has the risk to delay the entire project schedule in two ways. First, the design and construction schedule may be affected by the T&I planning. Second, the delay of T&I process can affect the project schedule directly. Therefore, effective and safe T&I planning in the early stage is important for the successful project. However, todays T&I planning is relying upon the experience of the related industry. And the planning has following restrictions: (1) Weather data acquisition points are limited as a start point, midpoint, and endpoint. (2) Weather forecasting data is not applied. (3) The physical response of tow is not applied. In this thesis, an offshore T&I simulation system is suggested to overcome these restrictions. The implemented system provides four functions: (1) Transportation planning simulation using a long-range weather history. (2) Transportation route optimization using a medium-range weather forecast. (3) Persistence analysis for installation using a long-range weather history. (4) Installation planning simulation using a medium-range weather forecast. The implemented system is applied to the T&I planning of semi-submersible offshore structure. The transportation route is assumed as the route from Rongcheng, China to the Jeju Island, Korea. The installation site is assumed as the west of Jeju Island where the transportation finishes. The application shows suggest the 1) right timing for transportation, 2) optimal transportation route, 3) persistence analysis result for installation, 4) weather windows for installation.