4 Petroleum production
4.4 Getting petroleum ashore
Most offshore oil and all offshore gas are transported to shore by pipelines; the safest, most cost-effective and environmentally friendly solution to transporting large volumes of petroleum without interruption. Pipelines may be buried if the seabed conditions are suitable or they may rest on the seabed and be covered with rock and gravel to provide protection.
Where seabed topography makes pipelines vulnerable or where they cannot be justified on economic grounds, tankers transport oil from production platforms or storage systems. Storage systems may be within massive fixed platforms or in floating ‘spar’ type offshore terminals. More commonly, storage is provided within tankers themselves and these are known as floating, production, storage and offloading (FPSO) vessels (see Section 4.2). FPSOs may remain on location at a single field for many years, offloading stabilised crude to a shuttle tanker at regular intervals. Alternatively the FPSO can move between one or more fields and the shore terminal, and be redeployed as each field is abandoned.