A flowline is described for producing hydrocarbons from a subsea well that
is comprised of a substantially neutrally buoyant tubular composite
umbilical. The flowline may possess electrical heating apparatus within
the tubular walls of the tubular composite umbilical to prevent waxes and
hydrates from forming within the flowline and blocking the flowline. The
electrical heating apparatus is comprised of at least one electrical
conductor disposed within the tubular walls of the composite umbilical
that conducts electrical current that is used to heat the tubular
composite umbilical. The tubular composite umbilical that contains any
produced hydrocarbons is substantially neutrally buoyant in the sea water
adjacent to the subsea well. Positively neutrally buoyant tubular
composite umbilical flowlines are also described.