Compressible Pipeline Inspection Pig for Defect Mapping

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Solution Overview

Problem

Existing pipeline inspection pigs face challenges in detecting internal geometry changes and blockages due to deposits and corrosion in oil and gas pipelines, particularly in subsea environments, as they often become jammed or fail to accurately locate localized defects, and their complex designs are prone to wear and limited elasticity.

Innovation Solution

A resiliently-compressible pipeline inspection pig with embedded strain gauges extending transversely, capable of radial compression by at least 30% without deformation, and equipped with a processing unit, data recording, and power activation, allowing for accurate mapping of internal pipeline profiles and defects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If contact sensors are used to detect pipeline wall defects, then measurement precision is improved, but device complexity increases and sensors wear quickly

Engineering Contradiction:
Improvedefect detection accuracyVSAvoidpig structure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces mechanical contact sensors with electromagnetic sensors that detect pipeline wall defects through non-contact means. The electromagnetic sensors measure changes in electromagnetic field properties caused by wall thickness variations, eliminating the need for physical contact and thereby reducing wear while maintaining detection capability

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

Solution Approach 2:

The patent introduces an electromagnetic field as an intermediary between the inspection device and the pipeline wall. The electromagnetic sensors detect defects by measuring disturbances in the electromagnetic field caused by wall thickness variations, rather than requiring direct mechanical contact with the wall surface

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If pigs are propelled by pressure differential, then ease of operation is improved, but pigs may become jammed in constricted pipelines

Engineering Contradiction:
Improvepig propulsion simplicityVSAvoidpig passage reliability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent employs a compliant pig body made of elastomeric material that can dynamically change its shape and cross-sectional area. This allows the pig to adapt to varying pipeline internal diameters and pass through constricted sections that would jam rigid pigs, while still maintaining the pressure differential propulsion mechanism

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the physical parameter of the pig's cross-sectional area by using a compliant elastomeric body that can expand and contract. This allows the pig to adjust its size to match the available pipeline clearance, enabling passage through deposits and constrictions while maintaining propulsion effectiveness

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If strain gauges are mounted on rigid structures, then measurement precision is improved, but adaptability to pipeline geometry changes decreases

Engineering Contradiction:
Improvestrain measurement accuracyVSAvoidadaptation to pipeline deformities
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent uses a compliant elastomeric pig body that can flex and deform to match pipeline geometry changes. Strain gauges are mounted on this flexible surface, allowing them to conform to pipeline deformities such as dents and bulges while maintaining measurement capability through the flexible mounting surface

Inventive Principle:
Principle #30Flexible shells and thin films

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

Enables effective detection and mapping of internal pipeline changes, including deposits and obstructions, without becoming jammed, providing precise data on pipeline conditions and allowing for efficient cleaning and maintenance, even in deep water environments.

Implementation Method 1

at least one strain gauge embedded in the material of the body, the or each strain gauge extending transversely with respect to the central longitudinal axis

Methodology Applied
Scientific EffectStrain: Deformation

Implementation Method 2

a body of resiliently-compressible material extending along a central longitudinal axis

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 3

capable of radial compression by at least 30% without deformation

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3775661B1Internal inspection of pipelines
Publication Date: 2022.02.23 SUBSEA 7 LTD
  • EP3775661B1 patent drawingFigure 1~3
  • EP3775661B1 patent drawingFigure 4a~4b
  • EP3775661B1 patent drawingFigure 5a~5c

AI summary

A pig for internal pipeline inspection comprises a body of resiliently-compressible material extending along a central longitudinal axis. At least one strain gauge is embedded in the material of the body. The or each strain gauge extends transversely with respect to the central longitudinal axis and is arranged to deflect and elongate longitudinally with longitudinal deflection of a forward end of the body.