Offshore ships are designed to perform a wide range of tasks associated with the offshore explorations and production of oil and gas. They are the main mode of transportation to carry equipment, goods and personnel to offshore platforms that operate deep in oceans.
Some of them like drillships can even be used as offshore platforms for oil and gas productions.
Offshore ships can broadly include Platform Supply Vessels (PSV), offshore barges, and all types of specialty vessels including anchor handling ships, drillships, well intervention ships, cable laying ships, ice breaking ships, as well as ships used for seismic researches.
Drillships are marine ships fitted with drilling equipment and the dynamic positioning system, which maintains their positions over oil well. They are primarily used for exploratory drilling and can operate in water depths up to 12,000 ft (3,700 m).
FPSO (Floating Production, Storage and Offloading) is an offshore vessel primarily used for processing and storage of oil and gas. They store the processed oil and gas until it is transferred to tankers or sent through pipelines.
Offshore barges are used for a wide range of marine tasks. They can be equipped with heavy lifting cranes, firefighting system, or can be used for pipe laying (Derrick Barge), or even can serve as an offshore accommodation to personnel.
Offshore Utility Vessels
Like platform supply vessels, these ships are also used to support production at offshore platforms. They are all-purpose supply vessels that support in offshore structure maintenance and low cost general assistance. Utility Vessels play an important part in all offshore oil operations, and may be used for a wide range of other marine work applications.
Platform Supply Vessels
As the name suggests, Platform Supply Vessels (PSV) are used to carry crew and supplies to the oil platform deep inside the oceans, and bring cargo and personnel back to shore. Their size varies from small 20 meter long ship to 100 meters large ship. These vessels are designed to transport a wide range of cargo such as drilling fluids, cement, mud, and fuel in tanks beneath the deck. The open deck on PSVs is normally used to carry other materials like casing, drill pipe, tubing and miscellaneous deck cargo to and from offshore platforms. Platform Supply Vessels are often equipped with firefighting equipment to deal with emergency situations.
Specialised Vessels or Specialty Vessels are used for a wide range of offshore functions such as anchor handling, offshore drilling, cable laying, ice breaking, seismic research, and well stimulation to name a few. They also play a major role in platform maintenance, and provide diving support, FPSO support, ROV support.