Electrically Heated Pipe Assembly for Subsea Deposit Control

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing subsea oil well product cooling systems face challenges with deposit formation on pipe walls, leading to blockages and efficiency losses, as current methods like pig-based systems and chemical injection are unreliable and costly, while Direct Electric Heating requires thermal insulation and is not always efficient.

Innovation Solution

A cooling system that periodically heats the pipe walls using electrical currents to prevent deposit formation, allowing the fluid to cool to ambient temperature and carry deposits as solid particles, eliminating the need for insulation and reducing costs, with a modular and flexible design suitable for subsea applications.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If Direct Electric Heating is used to maintain oil well product above deposit forming temperature, then deposit formation is prevented, but thermal insulation is required and efficiency is reduced

Engineering Contradiction:
Improvedeposit preventionVSAvoidheating efficiency
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent applies periodic heating pulses instead of continuous heating to prevent deposit formation. The heating element delivers intermittent thermal energy to the pipe wall, creating temperature fluctuations that prevent deposits from adhering permanently. This periodic action reduces overall energy consumption compared to continuous heating while maintaining effective deposit prevention.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The invention changes the temperature parameter dynamically by applying periodic heating pulses rather than maintaining a constant temperature above the deposit forming point. This parameter variation allows the system to prevent deposit adhesion through temperature cycling, improving energy efficiency while maintaining reliability.

Inventive Principle:
Principle #35Parameter changes

2Object-generated harmful factors

If pig-based systems are used to remove deposits, then deposits are scraped off, but moving parts and complicated piping reduce reliability

Engineering Contradiction:
Improvedeposit removalVSAvoidsystem reliability
Core Design Contradiction:
Object-generated harmful factorsVSReliability

Solution Approach 1:

The patent replaces the mechanical pig-based deposit removal system with a thermal field-based periodic heating system. Instead of using mechanical scrapers with moving parts, the invention uses controlled thermal pulses to prevent deposit adhesion and facilitate their natural detachment, thereby eliminating mechanical complexity and improving reliability.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The periodic heating system enables the pipe wall to self-clean by creating temperature conditions that prevent deposit adhesion and promote their detachment into the fluid flow. The system serves itself by using thermal energy to maintain clean pipe walls without requiring external mechanical intervention.

Inventive Principle:
Principle #25Self-service

3Object-generated harmful factors

If chemical injection is used to remove and prevent deposits, then deposits are dissolved or prevented, but cost increases due to chemicals and additional piping

Engineering Contradiction:
Improvedeposit controlVSAvoidpiping and valve complexity
Core Design Contradiction:
Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The patent replaces chemical injection systems with a periodic thermal heating system. By substituting chemical methods with controlled thermal pulses, the invention eliminates the need for additional chemical storage, injection piping, valves, and regeneration systems, thereby reducing device complexity and operational costs while maintaining effective deposit control.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention uses electricity for periodic heating as a replaceable energy source instead of expensive chemicals that require ongoing procurement, storage, and disposal infrastructure. The energy-based approach provides a simpler, more cost-effective solution for deposit prevention and removal.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

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

The system effectively prevents deposit formation, enhances efficiency, and reduces operational costs by using electrical heating to maintain fluid flow without the need for continuous heating, ensuring reliable and cost-effective operation in subsea environments.

Implementation Method 1

The heating is provided by passing an electric current through the wall of a pipe

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

The temperature of an oil well product on exit from a sea floor varies, but is normally in the range of 60°C to 80°C. It is therefore at a much higher temperature than the surrounding water at the sea floor.

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Data Source

PatentEP3426964B1Method of cooling an oil well product
Publication Date: 2024.05.15 EMPIG
  • EP3426964B1 patent drawingFigure 1
  • EP3426964B1 patent drawingFigure 2A~2B
  • EP3426964B1 patent drawingFigure 3

AI summary

Disclosed herein is a pipe assembly comprising: a pipe with an electrically conductive wall with a thermally conductive outer coating; a first electrical connector that is arranged in electrical contact with the wall of the pipe; and a second electrical connector that is arranged in electrical contact with the wall of the pipe; wherein the first and second electrical connectors are arranged to support the flow of an electrical current through the wall of the pipe to thereby heat the wall of the pipe; and in use, the pipe is arranged to allow cooling of the outer surface of the wall of the pipe by the surrounding environment of the pipe when the outer surface of the wall of the pipe is hotter than its surrounding environment. Advantageously, embodiments provide an effective, efficient and less expensive technique for heating the pipe in order to remove deposits for the inner walls of the pipes. Applications include the subsea application of cooling oil well products for cold flow.