[anthony-wohali]

Hopefully this will help explain the differences:

GEOMETRY PIG: This is an intelligent pig which collects piping shape information (i.e. deformation such as dents, ovality, etc.) and the pipelines physical location in relationship to GPS coordinates. The IMU data from a Geometry Pig can be overlaid onto Google Maps and other software to determine it’s exact positon in relation to the earth. Typically a client will conduct a Geometry survey using a geometry pig prior to inspecting a pipeline or piping system with a MFL , Ultrasound or EMAT intelligent pig to ensure these pigs can make it through the pipeline without becoming lodged inside.

MFL PIG: This is an intelligent pig which applies the Magnetic Flux Leakage (MFL) NDE approach. This is the oldest intelligent pigging approach on the market.
NON TETHERED PIG: This is a pig which has no cables in front (towing) or trailing behind (sending data back to a main computer). Most intelligent pigs on the market today are Non Tethered.

ULTRASONIC PIG: This is an intelligent pig which applies the Ultrasonic (UT) NDE approach. There are both Compression and Shear wave intelligent pigs being applied to inspect pipelines and piping systems.

EMAT PIGS: This is an intelligent pig which applies the ElectroMagnetic Acoustic Transducer (EMAT) NDE approach. This is the newest pigging approach on the market.