Petroleum Chemistry

Onshore/Offshore Support

Offshore drilling is a mechanical process where a wellbore is drilled below the seabed. It is typically carried out in order to explore for and subsequently extract petroleum which lies in rock formations beneath the seabed. Most commonly, the term is used to describe drilling activities on the continental shelf, though the term can also be applied to drilling in lakes, inshore waters and inland seas.

Offshore drilling presents environmental challenges, both from the produced hydrocarbons and the materials used during the drilling operation. Controversies include the on-going US offshore drilling debate.

There are many different types of facilities from which offshore drilling operations take place. These include bottom founded drilling rigs (jackup barges and swamp barges), combined drilling and production facilities either bottom founded or floating platforms, and deep water mobile offshore drilling units (MODU) including semi-submersibles and drillships. These are capable of operating in water depths up to 3,000 metres (9,800 ft.). In shallower waters the mobile units are anchored to the seabed, however in deeper water (more than 1,500 metres (4,900 ft.) the semisubmersibles or drillships are maintained at the required drilling location using dynamic positioning.

Based largely on development of the reserves of the North West Shelf and other onshore hydrocarbon basins, the industry extracts crude oil, condensate and natural gas from petroleum reservoirs deep beneath the Earth's surface. A large plant located at Withnell Bay near Dampier, produces liquefied natural gas (LNG) for export to Asian customers. Crude oil and most petroleum liquids are exported, and Australia's largest petroleum refinery at Kwinana in WA's south-west, produces petrol and diesel for local consumption. Natural gas is processed at plants located on islands off the WA coast and onshore, and then transported by pipelines to gas users throughout the state.