Page 283 - Pipeline Pigging Technology

Pipeline Pigging Technology

Vertical displacement - electronic monitoring of the tool movement can
plot changes in the vertical plane of the pipeline. This data is used to
determine sag or heave, which can be related to the earth movement caused
by ocean currents, unsupported spans in wash outs, frost heave or thaw,
earthquake, landslide, etc. Pipeline movement of this nature is nearly always
accompanied by deformation of the pipeline. Degrees of angle change in
slope is computable.
Horizontal displacement-very similar to sag or heave, only in a different
plane.
Bend location - monitoring tool movement on the vertical and horizontal
axes gives the ability to define pipeline bends as over, under, left or right. In
addition, the degree of this change of direction can be computed.
Orientation - the tool position related to pipeline o'clock position is
recorded. Orientation information allows the identification of the transverse
location of the anomaly.
Product temperature - continuous temperature profile of the pipeline.
Temperature data is used in determining such things as:

coating performance;
assigning risk priority to certain pipeline area in material degradation
studies, such as SCC attack;
efficiency studies for heated lines;
defining areas of concern for solids' suspension drop-out, such as
paraffin, asphaltines, NGL liquids, etc.;
determining efficiency and amounts of certain types of inhibitor pro-
grammes.

Product pressure - continuous pressure profile of the pipeline is used
primarily in efficiency studies affecting pumps and/or compressors. Studies
such as this can help determine the need for changes in HP requirements or
location of future pumping or compressor locations.
Above-ground markers - location of areas along the pipeline is accom-
plished by a lightweight, compact, weatherproof and accurate AGM system.

INFORMATION AND DATA HANDLING

The data derived from the sensing system listed above is stored on
magnetic tape and can be processed by several methods. The foremost of
these is by computer.

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