What are the best ways to maintain aging pipelines?

Inspection should be risk based approach. For aging pipeline, especially pipeline that has exceed design life, will require extra precaution. The treat does not comes only from fully utilized corrosion allowance, but the external coating may have deteriorate significantly which cause the coating breakdown factor increase thus increase the cathodic protection current demand. The sacrificial anode may have been fully consumed. External CP survey to check is then required. Another failure mode is fully utilization of the fatigue life, where crack start to develop. Crack inspection, especially small hairline crack is difficult to be inspected. It require advance tool with high precision and accuracy.

Employing advanced inspection techniques at regular intervals is essential for maintaining aging pipelines. Utilize cutting-edge inspection technologies like magnetic flux leakage (MFL) and guided wave ultrasonic testing (GWUT) to assess pipeline integrity. Like an oil pipeline operator conducts periodic MFL and GWUT inspections to detect internal and external corrosion, ensuring timely maintenance and prolonging the lifespan of aging pipelines.

The inspection interval does not need to be seven years for using smart pigs. It could be shorter depending on the condition of the pipeline (e.g. corrosion rate, crack propagation growth rate, etc.).

If a pipe joint is replaced, then its mechanical properties must be verified. Also, when new girth welds are made they should be checked for both weld overmatch requirements, and fracture toughness values could be determined, where all these properties could be measured nondestructively in-situ using the Automated Ball Indentation (R) test.

Prompt repair is not just for aging pipeline. Even new pipeline requires prompt repair to avoid further deterioration. Delay in rectification may incur higher risk of failure which escalates the consequence.

Implement a real-time monitoring system using sensors to track key parameters like pressure, temperature, and flow rates along the pipeline route. A natural gas pipeline operator employs a network of sensors to detect anomalies in pressure levels, allowing for immediate response and preventive maintenance to mitigate potential risks.

Challenges with old or aging pipeline is that the monitoring technology used at that pipeline may have obsolete or difficult to get replacement which cause difficulties in continuous monitoring. Refurbishment, rejuvenation or rejuvenation by using latest technology may require significant investment. The cost benefit analysis versus the requirement for safety, reliability and integrity shall be evaluated in holistic manner to get the optimum solution.

Continuous monitoring is paramount in pipeline maintenance. Leveraging my experience in automation and SCADA integration, I advocate for robust data acquisition and analytics. This enables real-time assessment of pipeline conditions, facilitating predictive maintenance strategies. By continuously monitoring variables like pressure, temperature, and flow rates, potential issues can be identified early, minimizing downtime and optimizing pipeline performance.

This involves replacing outdated components with modern materials or technologies to enhance reliability and longevity. For example, replacing old cast iron pipes with corrosion-resistant materials like PVC or upgrading outdated valves with newer, more durable models can significantly improve the pipeline's integrity and performance over time.

This is where early warning system is very important. Even though retrofitting new system into aging outdated pipeline may be difficult, it can be done by performing data analytic and trending of previous recorded operation and incident data.

Regular corrosion inhibitors injections, with calculating hydrocarbons stripping velocities limit to assure protection film is intact, also through sacrificial anodes, monitoring through coupons, propes, and regular UT thickness measurements.

The upgrade program MUST include determining the grade of the undocumented pipelines in order to verify the maximum allowable operating pressure. It is alarming for the safety of gas transmission pipelines to know that out of US 301,000 miles there is 169,000 miles without documentation (unknown or missing grade documents) as documented in the 2019 US regulations.

Regular fit for service assessment shall be conducted. Within certain year prior to design life expiry, pipeline life extension study shall also be conductes.

In addition to whatever mentioned above, I recommend the following based on my experience 1. Check CP current trend as well as confirm the effectiveness of CP based on the magnitude of impressed current in the case of submerged pipelines 2. Deploy leak detection system 3. Use smart piggging for for cleaning the internals of the pipeline 4.