A PIG is a Pipeline Inspection Gauge. PIG's scrape the inside of the pipeline and perform cleaning maintenance on the wall. Smart PIG's inspect the integrity of the line for any potential problems. Pipelines need to be cleaned regulary to prevent debris or buildup from occuring that may slow down the movement of the fluid inside. PIG launchers and receivers need to be installed at the approperate locations.
Nomenclature & Symbols
Pipeline Pig Types
- In-line inspection tool (ILI)
- Camera for visual inspections
- Geometry for detecting line thickness, sizes, changes in diameter.
- Mapping/ GPS pig
- ILI pigs are used for:
- Burial & coating
- Crack detection
- Internal inspection
- Leak detection
- Metal loss
- Line damage due to construction equipment
- Utility pig
- Utility pigs are used for:
- Batching pig
- Cleaning pig
- Cup pig
- Fill pig
- Gauging pig
- Sealing pig
- Sphere pig
Pipeline Pigging standards
- ASME B16.5 - Pipe Flanges and Flanged Fittings: NPS 1/2 through NPS 24 Metric/Inch Standard
- ASME B16.9 - Factory-Made Wrought Buttwelding Fittings
- ASME B16.47 - Large Diameter Steel Flanges, NPS 26 Through NPS 60
- ASME B16.36 - Orifice Flanges
- ASME B31.4 - Pipeline Transportation Systems for Liquid Hydrocarbons and Other Liquids
- ASME B31.8 - Gas Transmission and Distribution Piping Systems
- NACE ISBN 51316-7023 - Methodology for the Evaluation of Cleaning Pigs on Sludge Deposits from Corrosion Pits
- NACE ISBN 96034 - A Portable Pig Launcher and Receiver to Enable Maintenance and Smart Pigging of Production Pipelines
- NACE ISBN 96035 - Use of Intelligent Pigs to Detect Stress Corrosion
- NACE ISBN 96041 - Smart Pig Philosophy
- NACE ISBN 96048 - Solid Gel Pigs for Cleaning Production
- NACE ISBN 96049 - Intelligent Pigging: Policy, Recent Experience and Needs of a Petroleum Poerator
- NACE SP0102 - In-Line Inspection of Pipelines
- NACE SP0106 - Control of Internal Corrosion in Steel Pipelines and Piping Systems
- NACE SP0204 - Stress Corrosion Cracking (SCC) Direct Assesment
- NACE SP0206 - Internal Corrosion Direct Assesment Methodology for Pipelines Carrying Normally Dry Natural Gas
- NACE SP0208 - Internal Corrosion Direct Assesment Methodology for Liquid Petroleum Pipelines
- MTI Publication No. 14 - Manual on Closure Bolting for the Chemical Process Industries
Pipeline Pigging Glossary
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- Barred Tee - A tee or any fitting with a branch used in pipelines that is pigged and has a restriction bars welded internally preventing the pig from traveling down a branch connection.
- Batching Pig - A utility pig that creates a tight seal as it moves through the pipeline seperating liquids from gasses or other products being transpotred.
- Blanching Line or Equalizer Line - Allows the filling of the launcher from both sides of the pig.
- Bypass Line or Tie-line - This line is connected to the barred tee alowing the allowing the pigging line to continue flowing past the launcher/receiver.
- Bypass Valve or Mainline Bypass Line - Opens and closes the bypass line, on the barred tee branch.
- Camera Pig - A configuration pig with a camera and light source recording the inside of the pipeline.
- Cleaning Pig - A utility pig with brushes, cups, and scrapers for cleaning foreign matter from the inside of the pipeline.
- Cement Lined Pipe - Pipe that is internally coated with a mortar like compound that acts as a barrier between the carbon steel pipe and the process.
- Closure or End Closure - A flange or hinged device connected to the major barrel used to open or close the launcher/receiver for pig insertion or retrival.
- Concrete Coating - A liquid or semi-liquid covering that is applied to the surface of cured concrete to reduce the need for maintenamce and repair.
- Configuration Pig - An instrument pig that collects data of the inner contour wall of the pipe.
- Corrosion - The thinning of a pipe wall that is typically caused by a chemical reaction from a corroding fluid or agent and is limited almost exclusively to metal products.
- Corrosion Allowance - The amount of material in a pipe or vessel that is available for corrosion without affecting the pressure containing integrity.
- Corrosion Inhibitor - A substance that slows down the chemical reaction rate of corrosion on metal that is exposed to the environment.
- Corrosion Mapping - An ultrasonic method that identifies and maps corroded areas in a pipelineby yhe varying material thickness.
- Crack - Cracks can come from fatigue, grith welds, or seam welds.
- Cup Pig - A utility pig with cups made of a hard material making a tight seal against the pipe inside.
- Dewatering - In order to remove all the water from the pipe after hydro testing, a pig needs to be sent through the pipeline, this pushes the water out.
- Drag Force - The drag on a body as is moves through a fluid (gas or liquid).
- Drain Pit - When the closure is opened the sludge and/or liquid can drain into the pit along with the drain line. The pit can be drained by a vacuum ttruck or underground piping. The pit is covered with a removable grilled lid to stand on.
- Drain Line - Used to drain the major and minor barrels after the trap isolation valve in order to insert or remove the pig.
- Drain Nozzle - A flange connected to the major barrel for the kicker valve.
- Drain Valve - A valve at the bottom of the major barrel used to drain the line after the trap isolation valve.
- Flow Rate - Measures the amount of fluid that flows in a given time past a specific point.
- Fluid - A substance that deforms and changes position when put under stress. Fluids can be both liquids and gases.
- Foam Pig - A utility pig used for batching, cleaning, and removing products from the line..
- Fretting Corrosion - Takes place where there is friction between two metal surfaces.
- Gas - Able to be compressed to fit a confined space and expanded when released.
- Gauging Pig - A utility pig that permanently deforms to the shape of the pipeline providing a hands on look at the obstructions in the line.
- Gel Pig - A utility pig made of a thick gelled liquid.
- Geometry Pig - A configuration pig records measurements on the inside of the pipe like angles, gouges, pittings, radius, and any significant corrosion spots.
- Gouging - Mechanical removel of metal from the surface of the pipe.
- Holiday - A discontinuity in painted or coated surfaces.
- Hydro Test - This is a pressure test on pipelines and pressure vessels by filling them full of water, then pressurizing the line to check for leaks. After the test dewatering is performed.
- In-line Inspection - When the pipeline is inspected by examining the interior of the pipe.
- In-line Inspection tool - Devices , also called intelligent pigs or smart pigs, that inspect the interior wall of the line.
- Inhibitor - Can reduce the corrosion rate by presenting a protective film.
- Instrument Nozzle - Flanged or threaded outlets for instrumentation and relief valves on the launcher or receiver. There can be multiple.
- Instrumented Pig - A tool with instruments like recorders and sensors to examine the inside of the pipe.
- Internal Corrosion - The thinning of the interior pipe wall that is typically caused by a chemical reaction from a corroding fluid or agent and is limited almost exclusively to metal products.
- Kicker Line to Launcher - A line from the bypass line/tie-line to the front of the major barrel close to the closure. When the kicker valve is opened, fluid pushes the pig past the trap isolation valve down the pipeline.
- Kicker Nozzle - A flange connected to the major barrel for the kicker valve.
- Kicker Line from Receiver - A line from the bypass line/tie-line to the back of the major barrel close to the eccentric reducer. When the kicker valve is open, fluid passes to the bypass line and away from the launcher.
- Kicker Valve or Upstream Isolarion Valve - Opening into the valve launcher behind the pig. When opened, starts the pig on its way.
- Launcher - Used to launch a pig past the trap isolation valve and down the pipeline.
- Liquid - A specific volume and can hold any shape it is contained within.
- Magnetic Flux - This method can detect wall thickness from corrosion and pitting without affecting the pipe.
- Major Barrel - The pig is inserted or removed from the major barrel and comes after the eccentric reducer. Pipelines less than 8 inches in diameter, 2 inches larger, more than 8 inches in diameter, 4 inches larger than minor pipeline. There is an eccentric reduce, flat on botton, connecting major and minor barrels.
- Mapping Pig - A configuration pig used to produce an elevation and plan view of the pipeline route with collect data that can be analysed from the inertia sensing or some other technology.
- Mass Flow Rate - The average velocity of a mass that passes by a point.
- Minor Barrel - The pipe between the eccentric reducer and the trap isolation valve. There is an eccentric reduce flat on botton connecting major and minor barrels.
- Pig - Devices that are inserted into and travel throughout the length of a pipeline driven by a product flow. They were originally developed to remove deposits which could obstruct or retard flow through a pipeline.
- Pig Signal Detector - A mechanical switch to verify that a pig has left the launcher or has entered the receiver. Can also be placed along the line for locating the pig.
- Pig Trap - A launcher and receiver.
- Pig Trap Isolation Valve - The minor barrel is flanged to the isolation valve. The valve allows the pig to leave the launcher or enter the receiver.
Pigging Efficiency - Is expressed in percentage and always less than 100%.
- Pigging Valve - An alternative to conventional pig launchers. They are capable of launching and receiving foam, steel, and solid cast pigs in both cylindrical and spherical shapes.
- Pitting - A non-uniform corrosion of a metal, not in the form of cracks, whereby a number of cavities, are formed in the surface.
- Porosity - Happens when a contaminent or gas is absorbed into the weld puddle.
- Pressure - It is the force exerted perpendicular to the surface of an object and is expressed as force per unit area.
- Receiver - Used to receive a pig after pasting the trap isolation valve from the pipeline.
- Rectifier - Transformer - A device that uses electromagnetism to convert one current to another current.
- Rupture - There are numerous reasons a rupture can happen, depending on the material: age, brittleness, corrosion, internal pressure, movement, etc.
- Smart Pig - Collects information internally about the pipeline with electronic components.
- Solid Cast Pig - It is between a foam pig and steel pig having cups, disks or both and even brushes.
- Sour Corrosion: Hydrogen Sulfide - It is a flammable, poisonous gas, that occures naturally in some groundwater. It becomes corrosive when dissolved in water.
- Sphere Pig - A utility pig that may be solid or hollow and filled with air or water.
- Stress - The force per unit area of cross-section.
- Stress Corrosion Cracking - The combined effect of tensile stress and a corrosive environment.
- Surge Pressure - See Water Hammer
- Sweet Corrosion: Carbon Dioxide - A weak acidic gas found in condensate, crude oil, natural gas, and produced water and becomes corrosive when dissolved in water.
- Tensile Strength - The maximum stress a material can resist before it starts to elongate.
- Transformer - Rectifier - A device that uses electromagnetism to convert one current to another current.
- Ultrasonic Testing - Used to measure the pipe wall thickness perpendicular to the pipe.
- Upstream Isolarion Valve or Kicker Valve - Opening into the valve launcher behind the pig. When opened, starts the pig on its way.
- Utility Pig - Used to performing pipeline cleaning of debris and unwanted materials.
- Volumetric Flow Rate - The amount of fluid that flows in a given time past a specific point.
- Water Conductivity - The ability of water to conduct an electric current.
- Water Cut - The ratio of water produced to the volume of total liquid produced.
- Water Hammer - Occurs when a valve is suddenly opened or closed.
- Well Integrity - An operation of technical, operational, and organizational solutions to reduce fisk of controlled release of formation fluids throught the life cycle of a well.
- Yield Stress - See Yield Strength