Page 510 - Corrosion Engineering Principles and Practice

CHAPTER 12

Corrosion as a Risk

12.1 Risk Assessment
Industrial risk assessment is a careful examination of potential
hazards that may affect the operation of a system, be it large and
complex or relatively simple. These risks may be associated with the
risks to the safety and integrity of physical assets, risks to the
environment, financial risks from various decisions, and also risks
from corrosion or poor corrosion mitigation procedures. Corrosion-
related failures may be a major source of risk in many industry
sectors. In the offshore oil and gas installations, for example, corrosion
can be a life-limiting cause of deterioration by various corrosion
damage attacks of plant items.
In the offshore processing equipment, vessels and pipework are
fabricated from carbon-manganese steel. This is an economic choice,
based on life-cycle costing at the design stage of a project. The use of
carbon steels means potential hazards are present due to internal
corrosion damage from aqueous produced fluids that contain acidic
gases, carbon dioxide, and hydrogen sulfide [1]. In this industry,
corrosion related failures may result in hydrocarbon releases and
significant loss of production, as well as increased costs for
maintenance, repair, or replacement.
A considerable catalyst to the advancement of corrosion inspection
and monitoring technology has therefore been the exploitation of oil
and gas resources in extreme environmental conditions. Many
techniques that have been accepted in the oil and gas industries for
years are only now beginning to be applied in other industries such
as transportation, mining, and construction. Work in these conditions
has necessitated enhanced instrument reliability and the automation
of many tasks, including inspection.
In addition to the usual uncertainty of the onset or progression of
corrosion of equipment, the oil industry has to face ever changing
corrosivity of processing streams. The corrosivity at a well head, for
example, may oscillate many times during the life of an exploitation
field, between being benign to becoming extremely corrosive [2].

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