Pipeline Engineering - PE

Developments in Mechanical Developments in Mechanical Production Cleaning of PipelinesProduction Cleaning of Pipelines

Robin BrinhamRobin Brinham

PPSA Aberdeen Nov. 14thPPSA Aberdeen Nov. 14th

AgendaAgenda

• Why Pig a pipeline?Why Pig a pipeline?• Production Cleaning ProcessProduction Cleaning Process

– Data GatheringData Gathering– Phase 1 Proving PiggabilityPhase 1 Proving Piggability– Phase 2 Progressive CleaningPhase 2 Progressive Cleaning

• Factors Affecting Cleaning Tool DesignFactors Affecting Cleaning Tool Design• Designing the Right Cleaning ToolDesigning the Right Cleaning Tool• Case StudiesCase Studies• ConclusionConclusion

Why Pig A Pipeline?Why Pig A Pipeline?

Pigging is an operation to remove debris or Pigging is an operation to remove debris or

unwanted deposit build up in a pipelineunwanted deposit build up in a pipeline

Build up of deposit can:Build up of deposit can:• restrict fluid flow/increase pressurerestrict fluid flow/increase pressure• damage pumpsdamage pumps• prevent chemicals accessing pipe wallprevent chemicals accessing pipe wall• encourage corrosionencourage corrosion• prevent assessment of pipeline integrityprevent assessment of pipeline integrity

Planned pigging program is essential to overcome the abovePlanned pigging program is essential to overcome the above

Wax removed from a 14” line using a dual module tool

Production Cleaning Production Cleaning ProcessProcess

• Data GatheringData Gathering• Develop Pigging Program/Design Develop Pigging Program/Design

the Toolthe Tool• Implement the Production Implement the Production

Cleaning ProgramCleaning Program– Phase 1, prove piggabilityPhase 1, prove piggability– Phase 2, progressive cleaningPhase 2, progressive cleaning

Solid Works based pig design (computer modelling can be used to help confirm tool can traverse the line)

Data GatheringData GatheringEffective Production Cleaning depends critically on Effective Production Cleaning depends critically on gathering the appropriate datagathering the appropriate data

• Nature/quantity of debrisNature/quantity of debris• Handling eg NORM, black powder etcHandling eg NORM, black powder etc

• Line Conditions:Line Conditions:• temperaturetemperature

• pressurepressure

• flow ratesflow rates

• product chemistryproduct chemistry

• Line Features/GeometryLine Features/Geometry• Bends, ‘Y’s’, ‘T’s’, valves, id changes, Bends, ‘Y’s’, ‘T’s’, valves, id changes,

• Pigging HistoryPigging History

Heat damaged PU cup

Progressive CleaningProgressive CleaningPhase 1Phase 1

For infrequently pigged lines it For infrequently pigged lines it can be critical to prove can be critical to prove piggability.piggability.

• Low density followed by higher density Low density followed by higher density foams of increased diameterfoams of increased diameter• Risk of wax candle (esp. <12”)Risk of wax candle (esp. <12”)

• Once plugged d/p may harden Once plugged d/p may harden wax consistencywax consistency

• Consider the use of chemical additives Consider the use of chemical additives for wax dispersion prior to cleaningfor wax dispersion prior to cleaning

Foams of different diameter and coating

Progressive Cleaning Progressive Cleaning Phase 2Phase 2

Progressively increasing the Progressively increasing the “aggressiveness” of the tool “aggressiveness” of the tool minimises the risk of blockage minimises the risk of blockage

• Tool design will generally consist of a metal body Tool design will generally consist of a metal body with discs and/or cups attached or bothwith discs and/or cups attached or both• In the final stages they may have studs, pins, In the final stages they may have studs, pins, scraper blades or metal plates attachedscraper blades or metal plates attached• The removal of highly abrasive deposits e.g. The removal of highly abrasive deposits e.g. black powder or sand particularly in gas lines often black powder or sand particularly in gas lines often involves the use of pick up gelsinvolves the use of pick up gels• Pingers/Transmitters are often used to help Pingers/Transmitters are often used to help confirm tool locationconfirm tool location• The art is to remove enough but not too much of The art is to remove enough but not too much of the debris during any one pigging runthe debris during any one pigging run

Studded Cups

Factors Affecting Factors Affecting Cleaning Tool DesignCleaning Tool Design

Out of the many factors affecting pig design Out of the many factors affecting pig design three are especially critical:three are especially critical:

• Pipe SizePipe Size• Effectiveness of attachments eg brushes in small ID’sEffectiveness of attachments eg brushes in small ID’s

• Higher frictional resistance on the PU for small ID toolsHigher frictional resistance on the PU for small ID tools

• Weight stress for larger ID tools (friction, compression Weight stress for larger ID tools (friction, compression set/static stress..)set/static stress..)

• Pipe LengthPipe Length• Additional friction wear and possible heat build upAdditional friction wear and possible heat build up

• Bend RadiusBend Radius• Pig length, body tube diameter, sealing lengthPig length, body tube diameter, sealing length

56” tools, 54% weight saving using Aluminium.

Factors Affecting Factors Affecting Cleaning Tool DesignCleaning Tool Design

Other factors include:Other factors include:• Medium used to propel toolMedium used to propel tool• ID changesID changes• Valves, Y’s, T’s etcValves, Y’s, T’s etc• Subsea or Cross CountrySubsea or Cross Country

• extra sub sea features eg extra sub sea features eg manifolds, pigging loops etcmanifolds, pigging loops etc

• Pig Trap DesignPig Trap Design Dual diameter, unbarred “T’s”…

Designing The Right Designing The Right Cleaning ToolCleaning Tool

Each pipeline is different, use of ‘standard’ Each pipeline is different, use of ‘standard’ tool designs does not guarantee successtool designs does not guarantee success

In many cases a bespoke approach is In many cases a bespoke approach is required:required:

• Gather the dataGather the data

• Design the toolDesign the tool• Build the prototypeBuild the prototype• Test Loop trialTest Loop trial• Finalise Tool designFinalise Tool design• Client witnessed trialClient witnessed trial

The overall objective to maximise tool The overall objective to maximise tool effectiveness and to minimise riskeffectiveness and to minimise risk

Equal ‘Y’ test loop arrangement with 5D back to back bends

What’s New?What’s New?

Many recent developments Many recent developments are incremental:are incremental:

• Towing module for brushes etcTowing module for brushes etc

• Annular cleaning headsAnnular cleaning heads

• Brush redesignsBrush redesigns

• A new innovation is the Automatic A new innovation is the Automatic Multiple Pig Launching SystemMultiple Pig Launching System (AMPL)(AMPL) whereby depressurising the whereby depressurising the launcher will arm the next cleaning launcher will arm the next cleaning tool ready for launchtool ready for launch

AMPL pigs in launch cassette

Waxy Crude OilWaxy Crude Oil

Large trunk line with heavy wax deposits

• Cleaning to be affected along considerable length and at elevated temperature

• Substantial sand inclusion

• Tool needed to be robust with careful choice of PU grade

Cleaning tool after receipt, low flow,

check valves..

Mineral ExtractionMineral Extraction

Minerals (Zn/Pb) extracted from powdered ore Minerals (Zn/Pb) extracted from powdered ore then residue mixed with cement and piped then residue mixed with cement and piped underground for mine roof supportunderground for mine roof support

• 4.5km, 8” line used intermittently • Residue paste settled/set restricting line• Used progressive macerating pigs to remove hard sludge (5” to 6.5” in 0.5” increments).• Sludge removed in sections (too much to remove all at once)• Complete removal of all sludge achieved

Metal ‘cutters’ to break up sludge

Sludge layer breaking up

ConclusionsConclusions

• To effectively clean lines it is essential to gather the requisite To effectively clean lines it is essential to gather the requisite informationinformation

• Using a ‘standard’ pig will frequently give unsatisfactory Using a ‘standard’ pig will frequently give unsatisfactory results (every line different)results (every line different)

• The potential cost of inadequate pipeline cleaning can be The potential cost of inadequate pipeline cleaning can be very highvery high