are dispatched through
pipelines to perform
inner wall of the pipeline.
the line free of liquids.
the line during testing
internally gauge the line
inspect the line for internal
product separation - in
with on line maintenance programs.
the form of two, three, or
cups which are mounted on a mandrel.
Multi-section mandrels - for
purposes, poly pigs, cast urethane pigs, or
pig is introduced into a
are uncertainties as to its whereabouts. Many
of the problems
with pipeline operations, or maintenance may
be attributed to pigging
becomes lost, or jammed, the
is the location of the pig with a high degree
last decade, there have been
who have produced devices which are intended
to assist in tracking pigs
in both land and marine operations. These
devices take various forms:
devices will work given
the correct circumstances.
called a "pinger" as this
acoustic signals. It has many benefits
in offshore pipelines for
the pig's passage through a general
area. Its success has been limited
for the following reasons:
is battery operated, and
therefore has a limited
Acoustics echo in all directions,
and is therefore very difficult to
a liquid interface and
therefore cannot be utilized
in a dry line i.e. gas pipeline.
be utilized in land
vibration / shock
use correct frequencies.
amount of overburden over the
pipeline will prevent
the passage of audio signals.
battery operated unit which is
attached to the pig.
In order to
penetrate the pipe wall,
which is a natural
screen against radio signals, the
chosen frequency has to be extremely
low. The resultant signal through the
pipe wall is minute, and in
the receiving unit has to be ultra
difficulties with this
is battery operated
therefore has a limited
to operate in high
electrical interference areas.
/ leap froging.
remote signaling facilities.
encapsulated in a small container
housed within the
body of the pig.
method is not recommended for
the following reasons:
contamination of the
a high level of
material to be effective, handling
not allow for remote
monitoring, or systemization.
acceptable in most
countries in the world.
probably the earliest form of pig
requires either a cam type device or a
metal chain which makes a noise
as the pig travels through the
method cannot be recommended
for the following reasons:
device is primitive, and
not conductive with modern
order to detect its passage,
it requires labor to lay
with an ear to the ground or vent
post to listen for the pig
the event that the pig does
become stuck, it cannot be
Pigging Magnetic Pig Systemconsists
Pipeline Magnetic Pig
Magnetometer or Static.
gate Gradiometer - Search
The pig is designed as a magnetic
circuit with a field strength
to saturate the wall of the pipe
through which it is traveling. The
normally comprises of a steel body
which houses the magnetic section,
urethane cups, urethane spacers, a
nose plate designed to take shock,
a rear locking plate. The Magnetic
circuit may take the form of the
pig body, as in small size pigs or a
collar in larger diameter pigs.
collar is made up of two mild steel
discs with independent magnetic
around the center-line of the
circle. The magnetic circuit may be
in conjunction with cast urethane
pigs, poly pigs, or spherical pigs.
us we're always ready
The station or static magnetometers are remote
field passage indicators
which allow the operator to track the pig
through sections of line.
units not only indicate the pig's arrival at
that point, but indicate
the time of the event. An output from the unit
can also give a relay
thus providing for any number of ancillary
devices, i.e. radio
sona-alert (audio alarm), or input into the
clients' SCADA network.
indication is facilitated by high intensity
strobing beacon which can
seen from long distances especially from the
air, and at night. The
indicators may take the form of either
portable or permanent
or in marine applications, be sub sea or buoy
mounted. Add to this
communications and this unit will give our
clients all the flexibility
instrument provides a very essential part of
the total system, it is
to locate the whereabouts of a pig should it
become lost in a line. The
gradiometer may take the form of a portable
hand held unit, a "fish"
offshore location of pipelines or magnetic
pigs, or be used in
with an R.O.V. or with an airborne vehicle .
The Flux Gate Gradiometer
is designed to sense magnetic fields which
exist around all magnetic
These steady magnetic fields penetrate soil
and water, and so indicate
the presence of magnetic objects which may be
buried, or hidden from
sensors are contained within
a sensor tube
with a spacing of typically of one half meter
and are aligned
to within two seconds. The sensor tube can
either be detached, or
directly to an electronics housing which also
consists of a display.
difference in the magnetic field between the
two sensors is presented
the display which may take the form of either
a meter movement, or a
display, and also can be used to drive a
remote display or recorder.
device lends itself to interfacing with
and receive alert. This instrument complements
the system as it was
to be used with or without the other station
devices and is sold as a
alert device which will respond to the arrival
or departure of a pig
a small magnetic collar or spacer. The unit,
as its name suggests is
portable, and can be used on any line size. It
has the unique feature
being intrusive free, and not prone to
corrosion either internally or
as are other signaling devices. This
instrument not only signals the
or departure of a pig, but can count the
number of pigs and times.
will ensure that the unit
be activated, recording the times of the
event, until it is physically
turned off. In the auto re-set mode the unit
will re-set itself
20 seconds to await the arrival of further
pigs. Port-A-Sig signals, by
high intensity strobing beacon and also
provide a relay closure for
into automatic systems i.e., opening /closing
powered by 12 volts and can be
lithium batteries or solar power.
operation, alignment sheets
should be studied
in order to choose the best practical location
of the static
Where possible, areas of accessibility are the
obvious location to site
the stations. However, vulnerable places such
as road crossings, bends,
rivers, and railroad tracks should be
addressed. The static
are normally spaced at intervals of typically
one mile or convenient
From alignment sheets one can obtain the exact
linear location of
Dependent on whether the propellant is a
liquid, gas, or air, it should
be possible to work out an estimated time for
the pig's arrival at each
of the static
magnetometers is a very
simple operation. The line is located using a
pipe locator or
and a depth measurement noted. A small 2" hole
is augured just off the
line of pipe, as it is not necessity to make
direct contact with the
The sensor tube is installed normally 2-4 ft.
above the line, and made
firm, then the static head is attached and the
unit turned to the on
noted that in areas where the
line is buried
deeply it is not practical to use the static
magnetometers, and these
should be monitored by the Gradiometer.
magnetometers have been
pig may be launched. It will first pass the
Port-a-Sig which is sited
the pipe directly before it enters the ground.
This ensures a
launch. The Port-a-Sig will immediately
respond by signaling the
of the pig.
will then keep constant
recordings of line
pressure at both ends of the line. As the pig
passes each static,
will be given allowing the ETA of the pig's
arrival at the next station
to be up-dated.
the pig becomes stuck,
the first indication
will be an increase in pressure at the launch
trap and a decrease in
at the receiving trap. By timing the operation
this against known speed of the pig, it is
possible to calculate the
of the obstruction to within 100 ft.
an operator using a flux
will go to the area, locate the line, and
conduct the search for the
The Gradiometer will respond both on the
visual display and by its
audio system. By excavation, the defect
usually becomes apparent and
more skill on the part of
both during setup procedures, and positive
location of the defective
The operation is basically the same for
offshore as it is on land.
should be buoyed at strategic
the marine magnetometer sensors installed with
obtain valuable information
on how the pig
is running, it is advisable to set up two
points near to the launch.
will provide a key as to how the pig is
traveling which may be used to
assist in the event the pig gets jammed.
the pig does stick, a diver
a marine gradiometer can be used to determine
the exact location of the
pig. In deeper water, an R.O.V. mounted with
gradiometer can be used to
locate the pig.
Pipeline Systems & Servicein
Katy Texas. U.S.A.
a unique brand of services
to the World-Wide
Pipeline Industry. The uniqueness of StarTrak
stems from its in-house
of equipment, the specialist training of
employees, the quality control
of work and the sheer desire to provide
clients with a higher standard
of workmanship than any of the competition.
provided services and
throughout many parts of the world for both
land and marine pipeline
the extensive field
services combined with
research and development, which has been
carried out by StarTrak's
staff, the company is able to present a line
of products which will
a new technical dimension to the industry.
Profiling - Computerized
mapping of all buried
pipeline and utility networks on land and
Surveys - Full Profile
- Electronic Utilizing
StarTrak "One-Pass" system
Operations - Land
and Marine. StarTrak
"Pathfinder" magnetic pigging system
pipeline intrusions and
Computerized System Location
of areas with poor wrapping
Back to Technical Papers
Pigs - Cleaning - Gauging
Instruments - Magnetic
Sensing Equipment - Flux gate
Pig Monitoring Systems
Non intrusive Pig