Definition(s)
Mudline Suspension System
A casing suspension system that allows a well to be drilled using a surface BOP, surface wellhead and surface drilling equipment. The mudline suspension equipment provides for individual casing hangers to be installed with each casing string that interconnects with each other at a preset point below the mudline. The mudline suspension casing hangers do not provide a pressure barrier. After the well is drilled and cemented, these casing hangers allow for the removal of the casing string between the casing hanger and the surface wellhead. After these strings are removed, a cap can be placed over each casing string, isolating each casing string and the annular space between it and the previously capped casing string inside, at the casing hanger interface. These wells are tied back prior to the well completion in one of two methods: 1. Individually connecting two or more tie back casing production riser strings back to a surface casing head, tubing head/tubing hanger, and christmas tree (mudline surface well). Each string has its own tie-back connector, which provides a structural and pressure-containing connection between the casing strings below the mudline and the tie-back casing production riser string from the seafloor up to the surface. See Figure 13.1.3 in Appendix C. 2. Individually connecting two or more tie-back casing strings back to a subsea tubing head, using individual tie back connectors, followed by the installation of a subsea tubing hanger and subsea tree (mudline conversion well or mudline subsea well). See Figures 13.4.1 through 13.4.9 in Appendix C.
Source: API RP 90, Annular Casing Pressure Management for Offshore Wells, Upstream Segment. First Edition, August 2006. Global Standards
Mudline Suspension System
Drilling system consisting of a series of housings used to support casing strings at the mudline, installed from a bottom-supported rig using a surface BOP.
Source: API SPEC 17D, Design and Operation of Subsea Production Systems—Subsea Wellhead and Tree Equipment, Upstream Segment, Second Edition May 2011 (Errata September 2011). Global Standards
Mudline Suspension System
A casing suspension system that allows a well to be drilled using a surface BOP and wellhead. The mudline suspension equipment provides for individual casing hangers to be installed with each casing string that interconnect with each other at a preset point below the mudline. The mudline suspension casing hangers do not provide a pressure barrier.
Source: API STD 65 – Part 2, Isolating Potential Flow Zones During Well Construction, Upstream Segment, Second Edition, December 2010. Global Standards