Remote Star-End Heating Layout for Subsea Flowlines

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Solution Overview

Problem

Subsea pipelines face challenges in maintaining high temperatures to prevent wax and hydrate deposition, which can lead to pipeline plugs, especially in longer tie-backs, and existing electrical heating systems suffer from power loss and thermal damage due to multiple star-end connections.

Innovation Solution

A subsea electrical heating system with a termination effecting a short-circuit connection between heating cables, located remotely from the pipeline, allowing for extended heating to ancillary structures like spools and manifolds without dedicated power distribution, and featuring a modular star-end connection for easy maintenance and heat dissipation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If multiple star-end connections are made along the pipeline for heating, then heating coverage is improved, but power loss increases and thermal damage occurs

Engineering Contradiction:
Improveheating coverageVSAvoidpower loss
Core Design Contradiction:
TemperatureVSLoss of energy

Solution Approach 1:

The patent moves the star-end termination from the traditional in-line position along the pipeline to a remote offshore location, effectively changing the spatial dimension of the heating system architecture. This allows the heating cables to extend along the pipeline without intermediate star-end connections, reducing power loss while maintaining heating coverage through the extended cable run.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Temperature

If heating cables are extended to ancillary structures like spools and manifolds, then thermal management of external equipment is improved, but device complexity increases

Engineering Contradiction:
Improvethermal management coverageVSAvoidheating system complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The heating cable system is designed to serve multiple functions: it provides thermal management for the pipeline itself and simultaneously extends to ancillary structures such as spools and manifolds. This multi-functional approach allows a single heating system to protect multiple components, reducing the need for separate heating systems for each piece of equipment.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent uses the heating cable as an intermediary element that connects the power supply to both the pipeline and ancillary structures. By extending the cable run to remote locations and using it to trace multiple components, the system simplifies the overall architecture compared to installing dedicated heating systems for each piece of equipment.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of manufacture

If star-end connection is located at the pipeline end, then installation is simplified, but maintenance difficulty increases due to subsea location

Engineering Contradiction:
Improveinstallation easeVSAvoidmaintenance ease
Core Design Contradiction:
Ease of manufactureVSEase of repair

Solution Approach 1:

The patent extracts the star-end termination from its traditional position integrated with the pipeline structure and relocates it to a remote offshore location. This separation allows the termination to be accessed and maintained independently from the pipeline, facilitating easier repair and replacement without requiring intervention along the pipeline route.

Inventive Principle:
Principle #2Taking out (Extraction)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This solution effectively extends electrical heating to external equipment, reduces power loss, and facilitates easier maintenance by locating the star-end connection in a cold-water environment, enhancing thermal management and preventing pipeline plugs.

Implementation Method 1

Heat produced by passing an electric current along the cables is conducted firstly from the cables to the pipe wall and secondly through the pipe wall to the produced fluid flowing within the flowline

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

locating the star-end connection in a cold-water environment, enhancing thermal management and preventing pipeline plugs

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP3938618B1Subsea installations comprising heated conduits
Publication Date: 2024.08.07 ACERGY FRANCE
  • EP3938618B1 patent drawingFigure 1~2
  • EP3938618B1 patent drawingFigure 3~4

AI summary

A subsea installation for the production of hydrocarbons comprises a flowline and a group of heating cables extending along the flowline. A star end termination effecting short-circuit connection between the heating cables of the group is located at a subsea location remote from the flowline. For example, a subsea structure or fluid conduit in fluid communication with the flowline, such as a PLET or a spool, may be interposed between the termination and the flowline. The termination may be a module that is connectable electrically to the heating cables via flying leads and connector hubs.