A free-standing riser system connects a subsea source to a surface structure. The system
includes a concentric free-standing riser comprising inner and outer risers defining an
annulus there between. A lower end of the riser is fluidly coupled to the subsea source
through a lower riser assembly (LRA) and one or more subsea flexible conduits. An upper
end of the riser is connected to a buoyancy assembly and the surface structure through an
upper riser assembly (URA) and one or more upper flexible conduits, the riser also …

(60) Provisional application No. 61/392.443, filed on Oct. cally connected to a buoyancy
assembly that applies upward 12, 2010, provisional application No. 61/392,899, tension to
the riser. The riser may be insulated for flow assur filed on Oct. 13, 2010. ance, either by a
flow assurance fluid in the annulus, insula tion of the outside of the outer riser, or both. The
system may (51) Int. Cl. include a hydrate inhibition system and/or a Subsea dispersant E2IB
(7/01(2006.01) system. The Surface structure may be dynamically posi E2IB 36/00(2006.01) …