Page 114 - Pipeline Pigging Technology

A computerized inspection system

Problems with the manual system

In 1985, after eight years of operation of the Frigg Gas Transportation
System, pipeline engineers had increasing difficulties in accessing informa-
tion and performing analyses on the available pipeline inspection data.
Some of the reasons behind these difficulties -were as follows:

(1) The volume of inspection data collected since the commissioning of
the pipelines was huge and increasing rapidly. This was due in part to
improving techniques providing more data and additionally, as many inspec-
tion contractors became computerized, they were able to supply a greater
variety of reports, e.g. the 1986 campaign on Frigg lines produced 4 volumes
of Acoustic Reports and 18 volumes of ROV Reports (a volume being a 4-in A4
ring binder).

(2) The format and contents of reports were not conducive to post-
analysis, being often based on operational considerations such as: dive
references, direction of survey, etc.

(3) ROV surveys, as already mentioned, are only carried out on specific
areas. As a consequence, a lot of effort is required to compile an inspection
"history", to cross reference results and derive trends.

Reasons for considering computerization

Primarily, it was considered that computerization would overcome most
of the difficulties mentioned, or at least reduce their impact, and at the same
time provide additional advantages.
However, bearing in mind the large amount of data and the critical
timescales of the campaigns, apre-requisite of the system was to minimize the
data input effort by capturing data in computer form, e.g. magnetic tapes or
other types of interface for direct loading to the database. Indeed, inputting
data manually would have certainly defeated the purpose of the computeri-
zation, which was to reduce the amount of work.
This meant that the inspection contractors had to be computerized
themselves. In fact, by 1985, the majority of them were already using
computers:
Offshore - automatically to capture positioning and inspection data
such as UTM co-ordinates, kilometre posts, CP potential and sea bed
profile.

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