Objective

Assessment of the significance of features reported during inspections of pipeline integrity.

Issues

Pipelines can suffer many types of defects throughout their service life. Since these defects can cause permanent damage and thus reduce the integrity of the pipeline, their effect on the integrity of the pipeline must be assessed. Types of defects include corrosion, cracking, denting, gouging, dent/gouge combinations, stress corrosion cracking, and sour gas cracking.

Over the years, FFP methods, for example codes such as ANSI/ASME B31.G, RSTRENG, DNV, etc, have become more widespread resulting in optimized Inspection, Maintenance and Repair (IMR) strategies. Such methods are fully codified and form an integral part of pipeline integrity guidance documents such as API 1160, ASME 31.8S, and general industry best practice . In combination with a risk assessment approach, operators can thereby implement optimized and more cost-effective IMR approaches while improving pipeline safety and reliability.

• Review of the pipeline’s design, construction and operational history
• Damage categorization according to size and pipeline operating conditions
• Assessment of whether further inspection is required (e.g. for more accurate sizing or crack detection at the bottom of gouges)
• Assessment of whether immediate pressure reductions are necessary to avoid the possibility of time-related failure and to avoid stress-related failure while the pipe is being inspected or repaired
• For defects categorized as severe or extreme, defect assessment using the most appropriate method (e.g. RSTRENG, DNV RP-F101 etc)
• Use of results as a basis for repair analysis, remediation assessment or more advanced integrity analysis

Deliverables

An assessment of the technical basis to support repair decision making, feature remediation or more advanced integrity analysis.