Casing strings rising from the seafloor to the wellhead (fixed platforms) or casing strings attached to
the subsea wellhead rising from seafloor to a surface wellhead (hybrid wells).
Source: ISO 16530-1:2017, Petroleum and natural gas industries — Well integrity – Part 1: Life cycle governance, First Edition, March 2017. Global Standards
The portion of a pipeline extending from the seafloor to the surface is termed a riser. The function of a riser is to provide conduit(s) for the conveying of produced fluids and/or injection fluids between the seafloor equipment and the production host. Such risers are generally known as production risers in order to distinguish them from other types of risers such as marine drilling risers and completion/workover risers.
Source: API RP 17A, Design and Operation of Subsea Production Systems—General Requirements and Recommendations, Fourth Edition, Reaffirmed 2011. Global Standards
The casing string(s) rising from the seafloor to the wellhead on fixed platforms or the casing string(s) attached to the subsea wellhead rising from the seafloor to the surface wellhead on hybrid wells.
Source: API RP 90, Annular Casing Pressure Management for Offshore Wells, Upstream Segment. First Edition, August 2006. Global Standards
Source: API STD 65 – Part 2, Isolating Potential Flow Zones During Well Construction, Upstream Segment, Second Edition, December 2010. Global Standards