Marine riser, drilling riser. A string of specially designed steel pipe which extends from a drill ship or platform to the subsea wellhead. Marine risers are used to provide a return fluid-flow conductor between the well bore and the drill vessel and to guide the drill string to the [[wellhead]] on the ocean floor. The riser is made up of several sections including flexible joints and a telescoping joint to absorb the vertical motion of the ship or platform caused by wave action.

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