Integrated Pipeline Integrity Assessment for Life-Extension Decisions

Abstract

Oil and gas transmission pipelines operating beyond their original design life require comprehensive integrity assessments to ensure safe, reliable, and sustainable continued operation. Life-extension decisions should not rely only on asset age but must consider actual degradation conditions, operational risks, structural integrity, and remaining service capability. This study proposes an integrated pipeline integrity assessment framework to support technical decision-making for aging transmission pipelines. The proposed framework combines Failure Mechanism Identification (FMI), Risk Assessment (RA), Fitness-for-Service (FFS), and Residual Life Assessment (RLA) into a structured evaluation process. The methodology was applied to a 10-inch API 5L X52 condensate transmission pipeline located in Jambi, Indonesia. Inspection records, ultrasonic thickness measurements, operational data, and engineering evaluation reports were analyzed to determine the actual integrity condition of the pipeline. The results showed that external corrosion was the dominant degradation mechanism affecting the pipeline system. Risk assessment indicated that most evaluated pipeline segments remained within acceptable risk levels. Fitness-for-Service evaluation confirmed that the pipeline satisfied the required acceptance criteria, with sufficient wall thickness for continued operation. Residual Life Assessment demonstrated adequate remaining service capability beyond the original design life. This study confirms that integrated integrity assessment provides a systematic and technically justified approach for supporting risk-based pipeline life-extension decisions.