pig tracking by transmitter and EPD

Pig tracking tools : EPD and Geophone

PIG Tracking tools

During my job assignment in pipeline inspection, the most difficult work is monitoring and lead ILI or PIG Inspection. In general, we have 2 types i.e. cleaning pig and smart pig. Cleaning pig consist of low density foam pig, medium density foam pig, high density foam pig, cup pig and brush pig. After the pipeline is cleaned and meet the cleanliness criteria, we launch caliper and MFL or we called smart pig or ILI to inspect the physicals pipeline condition.

criss cross foam pig for cleaning pig
criss cross foam pig for cleaning

During the pig operation, the pig is likely to be stuck, stall or blocked by the elbow, deformed pipelines and other pipeline accessories. Thus, the pipeline ILI / pig inspection needs the use transmitter to track the position of the PIG in real time. Transmitter is installed on the pig, and pig operator use EPD – Electronic Pig Detector – to track the pig position. In field work, there are many conditions that caused pig unable to be tracked. This condition we called as UNTRACKING. Some time, the pig operator use another tool called Geophone to track the pig position.

ILI Transmitter and EPD Geophone tools detection
ILI Transmitter and EPD
EPD transmitter geophone
EPD (Electronic Pig Detector) detect transmitter signal

In simple terms, the geophone uses a mass wrapped around a wire that is in a magnetic field. When the sound waves that arise from the friction of the pig with the pipe travel to the pipe and hit the geophone sensor, a vibration will occur. These vibrations move the masses inside the geophone. When the mass moves at a certain speed, it will produce an electromotive force which can be read with a simple voltmeter. It can be seen that the value read on the voltmeter will be proportional to the mass movement speed (v) when the sensor vibrates. For people who are not accustomed to using a geophone, it will be difficult to distinguish the sound of a pig traveling in a pipe or the sound of a fluid.

geophone for pig tracking
geophone for pig tracking

When the pig operator uses low density foam pig, it is impossible to mount the transmitter and tie it inside the foam pig. So the only way to do pig tracking is to use a Geophone or manually, which is to listen to the low density foam pig friction in the pipe with your ear without the aid of tools. For pig operators with decades of experience, it is very easy to detect the pig passing in the pipe (above ground pipeline). Unfortunately, it will be very difficult to do if the pipe is located underground or the location of the pipe is close to a highway, market, near a train station or airport.

Here are some tips and tricks for PIG tracking

  1. Calculate the estimated pig speed and time required for the pig to run in the pipe.
  2. Make sure the battery used in the transmitter is new
  3. Do a test on the work function of the transmitter and EPD
  4. Determine the tracking points. for example every 1 km or every 500 m. the pig tracking location interval is adjusted to the pig speed.
  5. Prepare a spare battery for the EPD
  6. Adjust the gain of EPD as appropriate, depend on pig speed and pipeline location
  7. If there is an UNTRACKING condition, immediately do pig hunting. calculate the estimated volume of fluid (flowrate) that has entered the pipe during the pigging process and use this data to calculate the estimated pig location.

related article

  1. ILI inspection
  2. Guided wave inspection

You can also read transmitter specification made by ROSEN in this url : https://www.rosen-group.com/global/solutions/products/instruments.html

ITX 806 EX TRANSMITTER.

ITX 806 EX is capable of negotiating 1.5D bends and greater and available for all pipe sizes > 8 inches.  This transmitter has maximum operating time approximately 500 hours.  ITX 806 EX has a signal range of up to 20 meters (65 feet).

Key advantages:

Accurate, robust and reliable
Mounts on any 8″ or larger ILI or cleaning tool
Designed for all products and media
500 hours of continuous operation, runs with a rechargeable battery
Internal ON / OFF switch
ATEX certified according to ATEX Directive 94 / 9/ EC (II 2G Ex px[i] IIB T4), Zone 1 and 2
Also available on demand: ITX 804 Ex Transmitter.

Pig operator frequently faced pig stuck inside the pipeline. To solve this problem, they will launch “a rescue pig” to kick the first pig. There fore they usually bring additional pig and additional transmitter to the field.

 

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