Production risers having rigid inserts and systems and methods for using

An apparatus for facilitating a change in diameter of a riser for transporting production fluids from a subsea well to a production facility on a floating structure after an initial period of production, comprising:

• a. a production riser having a topsides end for attaching to a riser hanger assembly on the floating structure, a subsea end for supporting on a pipeline end termination structure located on a seabed and attaching to a subsea pipeline, an outer production riser surface and an inner production riser surface, wherein the inner production riser surface comprises a polished recessed seal face proximate the subsea end for receiving one or more seal elements and a recessed lock groove proximate the polished recessed seal face;
• b. a protective sleeve proximate the subsea end for covering the polished recessed seal face, wherein the protective sleeve has an outer sleeve surface for partially engaging the inner production riser surface and an inner sleeve surface comprising a groove therein for receiving a sleeve removal tool;
• c. a temporary retaining ring in the recessed lock groove in the inner production riser surface for holding the protective sleeve in place during the initial period of production;
• and
• d. an insert riser having an insert riser length, an outer insert riser surface and an inner insert riser surface, for insertion into the production riser following the initial period of production, wherein the insert riser comprises one or more seal elements around the outer insert riser surface for engaging the polished recessed face of the production riser and a locking ring around the outer insert riser surface for fitting into the recessed lock groove of the production riser.