Flexible Heated Pipe Cover for Subsea Hydrate Blockage Removal

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Solution Overview

Problem

Current methods for addressing blockages in fluid transport pipes, such as hydrates and paraffins, are inefficient, costly, and risky, often requiring lengthy depressurization, mechanical interventions, or localized heating, which can be impractical and pose risks due to pressure irregularities and the need for specialized equipment.

Innovation Solution

A removable cover with a flexible, elongated body and integrated heating elements, accompanied by temperature sensors, is deployed to heat the pipe and dissolve blockages over a significant length without precise localization, using a surface-based unit connected via a flexible link, allowing for efficient and controlled heating and monitoring.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If depressurization is used to unblock hydrates, then hydrate plugs can dissolve, but the pipe may collapse under external pressure and the process takes several months

Engineering Contradiction:
Improveunblocking effectivenessVSAvoiddissociation time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The invention changes the physical parameter approach from pressure-based (depressurization) to temperature-based (heating) dissociation. By applying thermal energy through heating elements wrapped around the pipe section, hydrates are melted and dissolved without requiring prolonged depressurization, reducing intervention time from months to days while avoiding pipe collapse risk

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The heating system operates in periodic cycles with multiple heating zones that can be activated sequentially or simultaneously. The control unit manages periodic heating pulses and monitors temperature evolution, allowing efficient energy use and progressive hydrate dissolution without sustained high energy input

Inventive Principle:
Principle #19Periodic action

2Ease of manufacture

If localized heating is applied to treat hydrate plugs, then treatment can be targeted, but the location of the plug must be known in advance requiring lengthy investigations

Engineering Contradiction:
Improvetreatment targetingVSAvoidinvestigation time
Core Design Contradiction:
Ease of manufactureVSLoss of time

Solution Approach 1:

The system employs self-diagnostic capabilities through temperature sensors distributed along the pipe that automatically detect hydrate formation zones by monitoring temperature anomalies. This self-detection eliminates the need for separate investigation phases, as the heating and monitoring system identifies plug locations autonomously during operation

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

Temperature sensors provide continuous feedback to the control unit about thermal conditions along the pipe. When a hydrate plug is detected through temperature differential analysis, the system automatically adjusts heating element activation to target the affected zone, enabling responsive treatment without prior location knowledge

Inventive Principle:
Principle #23Feedback

3Reliability

If mechanical systems are introduced to dislodge blockages, then blockages can be removed, but operations are tedious, costly, and require production shutdown

Engineering Contradiction:
Improveblockage removalVSAvoidproduction continuity
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The invention replaces mechanical intervention systems (such as pigs or robots that require pipe entry and physical blockage disruption) with a thermal field-based solution. Heating elements wrapped around the pipe exterior transfer thermal energy through the pipe wall to melt and dissolve hydrates, eliminating the need for production shutdown and mechanical equipment deployment

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

4Productivity

If excessive depressurization is applied, then hydrate dissociation accelerates, but the pipe can collapse under external pressure

Engineering Contradiction:
Improvedissociation speedVSAvoidpipe structural integrity
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The invention transitions from pressure parameter control to temperature parameter control for accelerating hydrate dissociation. By applying controlled thermal energy through heating elements, the system achieves rapid hydrate melting and dissolution without altering the pressure regime, thereby maintaining pipe structural integrity while improving dissociation speed

Inventive Principle:
Principle #35Parameter changes

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 enables effective, rapid, and cost-efficient treatment of blockages along the pipe length, minimizing production interruptions and reducing risks associated with pressure irregularities, while providing comprehensive coverage without the need for precise blockage location.

Implementation Method 1

The cover (32) comprises a flexible, elongated body (40) and at least one heating element (42)... The heating element (42) heats the pipe (16)

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

The elongated body (40) is made of an insulating material... the insulating body reduces heat loss to the surrounding water

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Implementation Method 3

The cover (32) comprises... at least one temperature sensor (44)... the temperature sensor (44) detects the temperature of the pipe (16)

Methodology Applied
Scientific EffectTemperature sensing: Thermocouple

Implementation Method 4

The surface-based unit is connected via a flexible link, allowing for efficient and controlled heating and monitoring

Methodology Applied
Scientific EffectMechanical force transmission: Spring

Data Source

PatentEP3303895B1Removable cover intended for being arranged opposite a fluid-transport pipe submerged in a body of water, associated intervention assembly and method
Publication Date: 2024.11.20 TECH N POWER
  • EP3303895B1 patent drawingFigure 1
  • EP3303895B1 patent drawingFigure 2
  • EP3303895B1 patent drawingFigure 3~5

AI summary

The invention relates to a cover which comprises: an elongate body (40), capable of being applied opposite an outer surface of the pipe (16); and at least one longitudinal element (42, 44) for interacting with the pipe (16), supported by the elongate body (40). The elongate body (40) is reversibly deformable under its own weight, the elongate body (40) having a length of more than 10 m. The cover treats solid build-ups within a fluid-transport pipe in a straightforward and inexpensive manner.