Depending on the method and timing of the riser installation, a situation may exist where the SCR FlexJoint^® must be laid down on the seabed for an extended period of time to await final installation.

At seabed conditions, the cold subsea temperatures and hydrostatic pressure of the seawater work in concert to induce tensile loads on the elastomeric flex element contained in the SCR FlexJoint^®. Elastomers are able to sustain their greatest load carrying capability under compression but the effects of thermal shrinkage and external hydrostatic pressure can remove the compressive preload during a laydown situation.

Under selected conditions, detailed design and machining of the internal centering ball can provide adequate restraint to protect the flex element. At the deepwater conditions present in many of the more recent Gulf of Mexico (GOM) applications, a temporary mechanical restraint in the form of a laydown tool may be necessary.

A laydown tool clamped to the SCR FlexJoint^® extension applies a predetermined preload to the flex element using a pre-tension ring on the tool. A laydown collar or integral external ring machined into the extension is required as a seat for the laydown tool.

The laydown tool assures proper compression is maintained on the flex element, while also limiting over-rotation during laydown or pickup operations. After retrieving the SCR FlexJoint^®, the laydown tool is removed prior to final installation.

The laydown tools are available for lease by the customer. Oil States will provide a project specific document that delineates the recommended tools and procedures to field removal of the laydown tool.

 
SCR FlexJoint® Laydown Tool