Advanced in-line inspection of critical pipelines infrastructure in Hungary for MOL Downstream

Authors: Agnes Kovacs, MOL Downstream; Balint Szabo, ROSEN Group

This article outlines the collaboration between MOL Downstream and ROSEN for the inspection of three of their important pipelines in Hungary.

Background

MOL Downstream operates a strategic network of pipelines across Hungary, supplying crude oil and refined products to key industrial consumers across the country. Ensuring pipeline integrity is essential not only for operational continuity but also for environmental protection and public safety, especially in regions near densely populated zones. To address integrity risks and comply with high safety standards, MOL engaged ROSEN Group to perform advanced in-line inspections on selected high-priority pipelines.

Objectives

The inspection program focused on three critical assets with distinct risk profiles. The key objectives were to detect and characterize crack-like defects, assess integrity threats in previously affected pipelines, ensure the safe operation of infrastructure critical to national energy supply, and prioritize maintenance and mitigation strategies based on high-resolution data.

Scope of Work

ROSEN inspected three pipelines using advanced in-line inspection (ILI) technologies. The 8-inch Százhalombatta–Csepel pipeline connects the refinery in Százhalombatta to Csepel. Its primary risk is its proximity to densely populated areas. The inspection was performed using RoCD UT-C (Ultrasonic Crack Detection Survey in Circumferential Direction). This technology inspects circumferentially while detecting crack-like features oriented in the axial direction of the pipeline. The selected approach reflects elevated safety requirements due to potential third-party impact and public exposure.

The 12-inch Kápolnásnyék–Dombóvár transmission pipeline connects Kápolnásnyék and Dombóvár. A known crack field had previously been identified by MOL, and a crack-related failure had already led to a leak. The pipeline was inspected using RoCD UT-C technology, which is optimized for identifying axially oriented crack features. The inspection goal was the reassessment and detailed sizing of crack defects to prevent recurrence.

A section of the 24-inch Friendship (Druzhba) pipeline was also inspected. This pipeline plays a key role in supplying crude oil to the Danube Refinery in Százhalombatta and is considered critical national-level energy infrastructure. The inspection was carried out using RoCD UT-C technology, enabling reliable detection of axial cracking mechanisms in a high-consequence, high-throughput asset. The objective was to ensure long-term integrity.

Applied Methodology

ROSEN deployed advanced in-line inspection tools tailored to each pipeline’s risk profile. RoCD UT-C technology is used to detect axial crack detection and enables high-resolution data acquisition, as well as accurate sizing of crack depth, length, and orientation. An integrity assessment, including fitness-for-service evaluation, was performed based on detected anomalies. All inspections were executed without interrupting pipeline operations, ensuring minimal disruption to supply.

Field Verification

Following the in-line inspection, MOL Group Downstream, together with ROSEN Group, conducted a field verification campaign on the 8-inch Százhalombatta–Csepel pipeline to validate the ILI findings. Multiple non-destructive testing techniques were applied directly on site, including Magnetic Particle Inspection, Ultrasonic Thickness and Lamination Testing, and Phased Array Ultrasonic Testing. The field verification results demonstrated strong correlation between the anomaly depth measured by the ILI tool and the PAUT measurements. All detected features were confirmed as shallow, notch-like anomalies, consistent with the characteristics of pipelines of similar manufacturing type and vintage.

Key Findings

On the 8-inch pipeline, RoCD UT-C technology successfully identified axial linear features, which were subsequently validated through field verification, confirming high data reliability. On the 12-inch pipeline, detailed characterization of the defect growth behavior, enabling targeted repairs and reducing the likelihood of repeat leakage. For the 24-inch pipeline, the inspection confirmed the integrity of a strategically vital crude oil supply line, ensuring continued reliable operation.

Impact and Value

The inspection program delivered significant value to MOL. Safety was enhanced through reduced risk in populated areas. Strong correlation between ILI and field NDT measurements validated the inspection results and increased confidence in the data. Advanced crack detection enabled reliable identification of axial crack features using specialized ultrasonic technology. Early intervention supported effective risk mitigation, while operational reliability and regulatory compliance were strengthened through alignment with stringent safety standards.

Conclusion

Through collaboration with ROSEN Group, MOL Downstream successfully implemented a targeted integrity management program across three critical pipelines. The deployment of RoCD UT-C technology, combined with comprehensive field verification, enhanced defect detection capability, validated inspection accuracy, and ensured the safe and reliable operation of assets vital to Hungary’s energy supply.

Figure 1. Launcher Pipeline MOL

Figure 2. RoCD UT-C tool on-site