There are several kinds of offshore vessels which are being used for oil explorations: FSO: the most common is FSO, floating, storage and off-loading unit(FSO or FSU), is essentially a storage tanker in which processed oil is pumped from the fixed platform(o semi-submersible FPS) which has no storage capacity, the oil is offloaded from FSU to refinery. FPS: The floating production system is used to describe a production vessle which is connected to the sub-sea pipeline, rather than one which has capability to discharge oil into shuttle tankers. FPSO: like FPS, floating, production, storage and offloading vessel replaces a convetional platform. It is connected sub-sea pipeline. The oil is extracted FPDSO:is fitted with driiling derricks, floating, production, drilling, storage and off-loading vessels, FPDSO