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Steel Catenary Riser (SCR) flexible joints are used in deepwater operations as a common method of attaching an offshore pipeline or flow line to a deepwater floating oil production platform. The primary function of a flexible joint is to suspend the SCR from the host platform, providing an articulated interface between the host and the SCR pipe. This allows for angular motion between the host platform and the SCR, thus reducing the bending moments in the upper section of the SCR. Preventative maintenance and inspection of the flexible joints is necessary to ensure the highest safety and reliability; however, these tasks are complicated by a number of factors, including disruption to production, challenging locations on the asset, special tools, depth, production processes, awkward geometry, sea state, marine growth, and shallow water remotely operated vehicle (ROV) operations.
The criticality or risk for all scenarios relating to SCR failure modes must be dealt with through periodic inspections. Some failure modes include the following:
* Fatigue due to excessive Vortex Induced Vibrations (VIV);
* Cut or loss of choke control;
* Spool flange leakage;
* Asset exceeds design motions;
* Dropped objects;
* Riser clashing due to VIV;
* Fatigue due to excessive vessel motions;