Offshore Energy & Rigging
3 July, 2017
Let’s begin with some basic definitions: Currently, the term offshore means “off the coast”. Business wise, offshore is “the relocation of a business process from one country to another.” Offshore originally meant “islands in the open sea belonging to a country.” In oil and gas extraction, offshore refers to “the development of oil fields and natural gas deposits under the ocean.” Offshore, when used relative to hydrocarbons, refers to an oil, natural gas or condensate field that is under the sea, or to activities or operations carried out in relation to such a field.
Offshore construction is the installation of structures and facilities in a marine environment, usually for the production and transmission of electricity, oil, gas and other resources. In the wind energy sector, offshore is the use of wind farms constructed offshore, usually on the continental shelf, to harvest wind energy to generate electricity.
Offshore Energy: Offshore Crude Oil Extraction
Oil rigs are used for the offshore exploration and production of crude oil. Crude oil deposits in the ocean that permit underwater drilling and extraction are developed and exploited using oil rigs. The drilling platforms used for development are subsequently replaced in part by production platforms. 25 percent of the proven oil deposits worldwide are expected to be found in offshore deposits.
Offshore Energy: Offshore Natural Gas Extraction
Offshore rigs are also used for the underwater exploration and production of natural gas. In order to develop and exploit natural gas deposits under the ocean, drilling platforms are erected and later in part replaced by production platforms.
What does Offshore Rigging Mean?
Offshore Rigging is a mechanical process conducted when a maritime floating vessel is installed and used to drill an oil well under the sea bed. Since the oil or gas reservoir can be found in the sea as well, offshore rigs play an important role in the exploration phase for the oil production. Offshore Rigging is accomplished through a drilling rig which may be an offshore floating platform or a fixed platform in the sea bed.
These include bottom founded drilling rigs (jackup barges and swamp barges), combined drilling and production facilities either bottom founded or floating platforms, and deepwater 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. These units are installed on the offshore drilling rigs and are used by the drilling crew to drill a borehole in the sea bed. When an oil reservoir is found, the production phase starts and that is referred to as Offshore Rigging. Usually, floating storage and offloading (FSO) and production vessels are used to store and transport the drilled hydrocarbons.
Offshore energy production is more challenging than land-based installations due to the remote and harsher environment. Much of the innovation in the offshore petroleum sector concerns overcoming these challenges, including the need to provide very large production facilities. Production and drilling facilities may be very large and a large investment. Offshore drilling also presents environmental challenges, both from the produced hydrocarbons and the materials used during the drilling operation.