Page 14 - Reliability and Maintainability of In service Pipelines

Introduction 3

Twenty percent of Russia’s oil and gas system is almost at the end of its
design life and it is expected that in 15 years time, 50% of their pipelines will be
at the end of their design life (Mahmoodian and Li, 2017).
In Canada, there are 34,000 km of oil pipelines and 26,000 km of gas pipelines
where the prevention of corrosion-related failures at reasonable costs is also the
main concern (Sinha and Pandey, 2002).
“The Water Infrastructure Network” reported the annual cost for maintenance
and operation of the US national drinking water system at US$38.5 billion per
year, which includes corrosion costs of US$19.25 billion (WIN, 2000). A study
undertaken by The Water Services Association of Australia reveals that aggre-
gated annual corrosion cost to the Australian urban water industry is approxi-
mately US$736 million (WSAA, 2009).
In the United Kingdom there are approximately 310,000 km of sewer pipes
with an estimated total asset value of d110 billion (OFWAT, 2002). The invest-
ment for repair and maintenance of this infrastructure is approximately d40 bil-
lion for the period of 1990 2015 (The Urban Waste Water Treatment Directive,
91/271/EEC, 2012). It has been known that sewer collapses are predominantly
caused by the deterioration of the pipes. For cementitious sewers, sulfide corro-
sion is the primary cause of these collapses (Pomeroy, 1976; ASCE (69), 2007).
In Los Angeles, USA, approximately 10% of the sewer pipes are subject to
significant sulfide corrosion, and the costs for the rehabilitation of these pipelines
are roughly estimated at d325 million (Zhang et al., 2008). As an example of a
European country, in Belgium, the cost of sulfide corrosion of sewers is estimated
at d4 million per year, representing about 10% of total cost for wastewater collec-
tion and treatment systems (Vincke, 2002).
These statistics indicate that pipeline networks are faced with high emergency
repair and renewal costs, and frequent charges arising from increasing rates of
deterioration worldwide. On the other hand, budget limitations are significantly
restricting pipeline networks and reducing their capabilities in terms of addressing
these needs. Large investments are required for building new pipelines networks.
It is unlikely to be able to replace the existing pipe infrastructure completely over
a short period of time. Therefore to eliminate the high costs associated with pipe-
line failures, pipe network managers need to generate proactive asset management
strategies and prioritize inspection, repair, and renewal needs of pipelines by
utilizing reliability analysis. The failure assessment and reliability analysis of
pipelines can help asset managers to provide an improved level of service and
publicity, gain approval and funding for capital improvement projects, and man-
age operations and maintenance practices more efficiently (Grigg, 2003; Salman
and Salem, 2012).
It is also well known that the consequence of the failure of pipelines can be
socially, economically, and environmentally devastating, causing, for example,