This paper describes a low-cost pipeline inspection tool developed by RST Projects, Scotland. The methodology underpinning the operation of the tool is fundamentally different from conventional in-line inspection systems. This emphasis of the present paper is placed on the basis for this approach and an explanation of the advantages in comparison with conventional intelligent pigging methods. A discussion of the necessary technical innovations is given. A brief example, from an offshore pipeline survey, showing how spool pieces can be identified by detection of the weld signature is presented. With the current volatility in the hydrocarbon market it is believed that this lower-cost approach will offer considerable advantage particularly where pipelines are working with low profit margins or in extending the life of older lines.
Offshore and onshore infrastructure now accounts for more than 200,000 kilometre's of pipeline in Europe. A significant proportion of the offshore lines are near to, or have passed, their design life and operators are required to demonstrate continued fitness for purpose to extend their use; much of the present infrastructure in the UK is now reaching its 20–25 year design life. The early identification of factors, such as corrosion or mechanical damage, which will compromise pipeline integrity, is of great concern. The cost effectiveness of each line must also be maintained through the early identification of any condition, such as the build up of wax, which reduces production rate. This is particularly important for older lines that can rapidly become non-economic. These are often producing at low flow rates, where already low margins would be fatally compromised by extensive intelligent pigging programmes. The internal inspection of pipelines is undertaken by a combination of tools - so-called "intelligent" pigs - which can provide information on a variety of pipeline parameters.
