US 12,066,135 B2
Heating of subsea pipelines
Meric Pakkan, Stavanger (NO); and Per Moi, Bryne (NO)
Assigned to SUBSEA 7 NORWAY AS, Stavanger (NO)
Appl. No. 17/299,771
Filed by Subsea 7 Norway AS, Stavanger (NO)
PCT Filed Dec. 3, 2019, PCT No. PCT/EP2019/083558
§ 371(c)(1), (2) Date Jun. 3, 2021,
PCT Pub. No. WO2020/115079, PCT Pub. Date Jun. 11, 2020.
Claims priority of application No. 1819751 (GB), filed on Dec. 4, 2018.
Prior Publication US 2022/0018230 A1, Jan. 20, 2022
Int. Cl. F16L 53/32 (2018.01); E21B 43/01 (2006.01); F17D 1/18 (2006.01); F16L 9/19 (2006.01)
CPC F16L 53/32 (2018.01) [E21B 43/01 (2013.01); F17D 1/18 (2013.01); F16L 9/19 (2013.01)] 29 Claims
OG exemplary drawing
 
1. A method of maintaining production of hydrocarbon fluids subsea comprises;
directing a flow of hot production fluid from a subsea well into at least one production flowline pipe that extends toward a processing or storage location;
in a first mode of operation, transporting a flow of service fluid from a source of the service fluid along at least one service fluid pipe that extends along and adjacent to the production flowline pipe and, at least intermittently, injecting the service fluid from the service fluid pipe into the well or into the flow of production fluid upstream of the flowline pipe; and
in a second mode of operation, diverting at least some of the flow of the production fluid into the service fluid pipe to apply heat from the production fluid to the service fluid pipe, and transferring the heat from the service fluid pipe to the flowline pipe.
 
14. A subsea hydrocarbon production system, comprising:
at least one production flowline pipe for transporting a flow of hot production fluid from a subsea well toward a processing or storage location;
at least one service fluid pipe extending along and adjacent to the production flowline pipe for transporting a service fluid from a source of the service fluid toward an injection point upstream of the flowline pipe; and
a flow diverter upstream of the flowline pipe, the flow diverter being configured selectively to divert at least some of the flow of production fluid into the service fluid pipe to apply heat to the flowline pipe via the service fluid pipe.