In Line Inspection ILI Interval for Cross Country Pipelines

Gurjar, Sahab Singh (Cairn Oil & Gas, Vedanta Limited)


In line Inspection (ILI) Interval are often based on conditions that are assumed constant over long sections of pipeline - perhaps entire pipeline systems. Many pipeline operators are following the fixed ILI Interval based on statuary requirement irrespective of different local corrosion growth conditions prevailing on the particular pipeline system. Scheduling the ILI based on maximum interval defined in statuary requirement may be very unrealistic and pose threats to the integrity of these pipelines. This technical paper discusses the importance of ILI Interval, corrosion growth rate analysis, recent development to determine the ILI Interval, an engineering approach to calculate appropriate ILI-RunInterval, mitigation plan to extend the ILI-RunInterval for particular pipeline system. This technical paper would enhance the awareness among the pipeline operators to appropriately calculate the ILI-Run Interval which would cost beneficial to pipeline operators in long term without any integrity threats.