The oil, gas and chemical industries rely primarily on underground structures to transport and contain
their products. These structures include large underground transport pipelines, underground pipelines
and storage tanks, both at operating / production sites and at petrol retail stations. There is a constant
need to assess the integrity status to reduce risk of leaks and predict remaining lifetime expectance. A
reliable assessment of corrosion probability helps to define inspection programs, cathodic protection
system checks and maintenance programs.
A risk-based approach is used to assess corrosion probability and corrosion risk of underground
pipelines and storage tanks. A novel soil corrosion assessment method has been developed, as the
existing methods appeared to be inaccurate and/or inflexible. One of the innovations in the new method
involves the application of electrochemical measurement methods to assess soil corrosivity, replacing
the traditional pH and resistivity and salt content (e.g. chlorides) measurements. Used together with
other soil and structure related parameters, this measured soil corrosivity is used to assess corrosion
probability and the integrity risk (corrosion probability times consequences) for underground structures.
This paper outlines the soil corrosivity assessment method and application examples.