| CPC F16L 53/37 (2018.01) [E21B 17/003 (2013.01); E21B 36/04 (2013.01); E21B 43/01 (2013.01)] | 15 Claims |
|
1. An system for heating fluid transport pipes from at least one subsea well apparatus to a topside or onshore location, said system comprising:
at least one Direct Electric Heating conduit section having a conductive fluid transport pipe, said Direct Electric Heating conduit section arranged between the topside or onshore location and a distance to a subsea well apparatus,
wherein said Direct Electric Heating conduit section is connected to a first electrical power supply, coupled to a topside location having power, is said first electrical power supply being connected to a near end of said conductive fluid transport pipe of said Direct Electric Heating conduit section, and to a far end of the electrically conductive fluid transport pipe via a piggyback cable, mounted on the electrically conductive fluid transport pipe, to form a circuit, such that electrical current circulates first though said piggyback cable and then back through said electrically conductive fluid transport pipe and the surrounding seawater, said electrically conductive fluid transport pipe having a resistance configured to convert electrical current to heat when electrical current is circulated in the circuit,
wherein said system also has a heat traced conduit section, separate from said Direct Electric Heating conduit section, that is arranged between an end of the Direct Electric Heating conduit section and the subsea well apparatus in the longitudinal direction,
wherein the at least one heat traced conduit section is arranged on a second inner most fluid transport pipe and has,
at least one electric heating cable arranged on the outside wall of the second inner most fluid transport pipe starting at said subsea well apparatus and extending to and terminating near said end of said Direct Electric Heating conduit section, the electric heating cable comprising two conducting elements that are enclosed within electrical insulation,
at least one thermally insulating layer arranged to cover the second inner most fluid transport pipe and the at least one electrically insulated electric heating cable, and
a second electrical power supply, coupled with said topside location having power, connected to the at least one electric heating cable through said subsea well apparatus,
wherein said first electrical power supply for said Direct Electric Heating conduit section and said second electrical power supply for said heat trace conduit section are separate electrical paths not connected in series.
|