Page 468 - Pipeline Pigging Technology

Pigging research

PIGGING RESEARCH

INTRODUCTION

Pipeline pigs may be broken down into two fundamental groups: conven-
tional pigs, which perform a function such as cleaning or dewatering, and
tntetttgentptgs, which provide information about the condition of a pipeline.
Conventional pigs have been in use for over 100 years, compared to less than
25 years for intelligent pigs.
Few, if any, of the features incorporated in the design of conventional pigs
are the result of fundamental research and development, while intelligent
pigs owe almost everything to concerted R&D programmes.
Millions of dollars have been spent on intelligent pigs because there was
(and is) a clearly-defined need. Conventional pigs have simply evolved.
The reason that they have evolved, rather than being the result of
development programmes, is that specific performance requirements have
never been set.
A pig is considered "Good" if it travels through a pipeline without
problems, preferably arriving in pristine condition. What it has done during
the run is never precisely known. Whether its performance could have been
improved is generally not apparent until a different pig is run. Only then is it
possible to compare such things as the relative difference in pressure drop,
the volume of water or condensates removed, the rate of wear on the cups or
cleaning elements, etc. - but even then, it still provides only a measure of
relative, rather than absolute, performance.
Invariably, when one pig "outperforms" another, a debate ensues as to
why, and certain conclusions are reached. This information is passed back to
the manufacturer, who incorporates it in his subsequent designs, and so the
evolutionary process continues.
The problem with evolution is that it takes a very long time and it doesn't
always work. Modern man may have evolved from the ape - but there are still
a lot of apes around

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