Selecting NDE Technology for Insulated Subsea Jumpers

Reliability and integrity of subsea equipment are critical for safe and efficient operations within the offshore energy industry. Internal corrosion of hydrocarbon-carrying pipelines and subsea production equipment is a recognized threat. Typical monitoring techniques such as corrosion coupons, probes, corrosion inhibitor (CI) performance, and produced fluid analysis, provide valuable insights into the internal condition of pipelines. However, direct inspection remains vital for data gathering and validating the health of the internal flowpath within the subsea equipment, especially in harsh and challenging environments. Nondestructive examination (NDE) techniques are invaluable in assessing the internal condition of subsea equipment, particularly in insulated piping. This article is a case study describing an approach to identifying critical locations, selection of an applicable NDE tool, and execution of a chosen NDE inspection technique on aging subsea production jumpers.

The subsea production jumpers are located in a field within the Gulf of America and have operated without confirmation of the corrosion allowances established in the original design. This lack of verification presents a critical challenge: the long-term integrity of these components remains uncertain, and the potential degradation could impact operational uptime and reliability. Addressing this gap in corrosion assessment is essential to ensure continued performance. The subsea field has upwards of 20 subsea jumpers that have been in operation for 5 to 10 years, and the internal corrosion threat is driven by sweet CO₂ corrosion and erosion. Based on relevant monitoring parameters, operational data and risk-based assessment output, inspections were deemed necessary to ensure fitness-for-service. However, there was a unique challenge: the majority of the jumpers are well jumpers, which connect the subsea trees to the production manifold, making them unpiggable.

Inspection Locations and Methodology

The subsea jumpers are coated in fusion-bonded epoxy (FBE) and insulated with 2 inches of glass syntactic polyurethane (GSPU), which prevents the application of conventional external ultrasonic testing (UT) techniques. The jumpers are located in water depths of 3,000 feet and have complex physical characteristics such as bends, elbows, and ancillary equipment such as acoustic sand detection (ASD) and multiphase flow meters (MFPM), limiting access in specific locations. An approach to identify reliable NDE tools for project-specific critical locations was evaluated using the flow chart shown in Figure 1.

A methodology for the prioritization of jumper inspection was based on the following criteria:

• Years of service
• Past and future production profiles
• Corrosion inhibitor injection history
• Design margins for wall thickness

Inspection locations were identified based on determining corrosion hotspots using mechanistic corrosion modeling, using well flows for well jumpers and commingled flow for flowline jumpers. The corrosion models were evaluated based on historical and future production rates, water cuts, estimated corrosion rates, and wall loss, as well as the flow regime and water wetting conditions.