Pipeline Engineering - PE Developments in Mechanical Production Cleaning of Pipelines Robin Brinham PPSA Aberdeen Nov. 14th

Agenda Why Pig a pipeline?Why Pig a pipeline? Production Cleaning ProcessProduction Cleaning Process –Data Gathering –Phase 1 Proving Piggability –Phase 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? Pigging is an operation to remove debris or unwanted deposit build up in a pipeline 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 above Wax removed from a 14” line using a dual module tool

Production Cleaning Process Data GatheringData Gathering Develop Pigging Program/Design the ToolDevelop Pigging Program/Design the Tool Implement the Production Cleaning ProgramImplement the Production Cleaning Program –Phase 1, prove piggability –Phase 2, progressive cleaning Solid Works based pig design (computer modelling can be used to help confirm tool can traverse the line)

Data Gathering Effective Production Cleaning depends critically on gathering the appropriate data Nature/quantity of debris Nature/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/Geometry Line Features/Geometry Bends, ‘Y’s’, ‘T’s’, valves, id changes,Bends, ‘Y’s’, ‘T’s’, valves, id changes, Pigging History Pigging History Heat damaged PU cup

Progressive Cleaning Phase 1 For infrequently pigged lines it can be critical to prove piggability. Low density followed by higher density foams of increased diameter Low density followed by higher density foams of increased diameter Risk of wax candle (esp. <12”) Risk of wax candle (esp. <12”) Once plugged d/p may harden wax consistencyOnce plugged d/p may harden wax consistency Consider the use of chemical additives for wax dispersion prior to cleaning Consider the use of chemical additives for wax dispersion prior to cleaning Foams of different diameter and coating

Progressive Cleaning Phase 2 Progressively increasing the “aggressiveness” of the tool minimises the risk of blockage Tool design will generally consist of a metal body with discs and/or cups attached or both Tool design will generally consist of a metal body with discs and/or cups attached or both In the final stages they may have studs, pins, scraper blades or metal plates attached In the final stages they may have studs, pins, scraper blades or metal plates attached The removal of highly abrasive deposits e.g. black powder or sand particularly in gas lines often involves the use of pick up gels The removal of highly abrasive deposits e.g. black powder or sand particularly in gas lines often involves the use of pick up gels Pingers/Transmitters are often used to help confirm tool location Pingers/Transmitters are often used to help confirm tool location The art is to remove enough but not too much of the debris during any one pigging run The art is to remove enough but not too much of the debris during any one pigging run Studded Cups

Factors Affecting Cleaning Tool Design Out of the many factors affecting pig design three are especially critical: Pipe Size Pipe 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 set/static stress..)Weight stress for larger ID tools (friction, compression set/static stress..) Pipe Length Pipe Length Additional friction wear and possible heat build upAdditional friction wear and possible heat build up Bend Radius Bend Radius Pig length, body tube diameter, sealing lengthPig length, body tube diameter, sealing length 56” tools, 54% weight saving using Aluminium.

Factors Affecting Cleaning Tool Design 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 manifolds, pigging loops etcextra sub sea features eg manifolds, pigging loops etc Pig Trap DesignPig Trap Design Dual diameter, unbarred “T’s”…

Designing The Right Cleaning Tool Each pipeline is different, use of ‘standard’ tool designs does not guarantee success In many cases a bespoke approach is required: Gather the data Gather the data Design the tool Design the tool Build the prototype Build the prototype Test Loop trial Test Loop trial Finalise Tool design Finalise Tool design Client witnessed trial Client witnessed trial The overall objective to maximise tool effectiveness and to minimise risk Equal ‘Y’ test loop arrangement with 5D back to back bends

What’s New? Many recent developments are incremental: Towing module for brushes etc Towing module for brushes etc Annular cleaning heads Annular cleaning heads Brush redesigns Brush redesigns A new innovation is the Automatic Multiple Pig Launching System (AMPL) whereby depressurising the launcher will arm the next cleaning tool ready for launchA new innovation is the Automatic Multiple Pig Launching System (AMPL) whereby depressurising the launcher will arm the next cleaning tool ready for launch AMPL pigs in launch cassette

Waxy 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 Extraction Minerals (Zn/Pb) extracted from powdered ore then residue mixed with cement and piped underground 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

Conclusions To effectively clean lines it is essential to gather the requisite informationTo effectively clean lines it is essential to gather the requisite information Using a ‘standard’ pig will frequently give unsatisfactory results (every line different)Using a ‘standard’ pig will frequently give unsatisfactory results (every line different) The potential cost of inadequate pipeline cleaning can be very highThe potential cost of inadequate pipeline cleaning can be very high