ETAP Subsea Flowline

The ETAP project for Shell involved designing and installing a 48 km, 12″/16″ pipe-in-pipe (PIP) system operating in 90 m water depth. Therefore, the high-pressure (600 bar) and high-temperature (155°C) conditions required a custom solution that could handle  thermal expansion, transients, and fatigue. Additionally, the insulation needed to meet stringent performance criteria while maintaining a compact design.

ITP developed a tailored solution for the ETAP project, incorporating several key features to address the high-pressure (600 bar) and high-temperature (155°C) challenges: 

• Compact Design: The system was designed to be compact while meeting Shell’s insulation requirements, utilizing Izoflex pipeline insulation to achieve a U-value of 1.2 W/m².K, optimizing space without compromising thermal performance. 
• Tulip Inserts for Strain Coupling: The custom tulip insert design was incorporated to ensure distributed strain coupling, effectively managing thermal expansion and transient loads throughout the pipeline. 
• Field Jointing for HP/HT: Advanced field jointing techniques, including full-penetration outer pipe welding, were used to ensure the integrity of the pipeline and enable the system to handle the extreme thermal expansion and fatigue demands of the HP/HT environment. 
• Local Fabrication: The system was fabricated in Scotland, ensuring high-quality manufacturing with a focus on local content and expertise. 

This integrated approach provided a reliable, high-performance pipeline solution for Shell’s demanding offshore field. 

As a result, this solution ensured safe and efficient oil transportation under challenging subsea conditions. 

The project’s success stemmed from innovative engineering solutions, including the use of Izoflex insulation and a robust welding approach that met Shell’s high standards. Moreover, the custom tulip design ensured effective strain management and enhanced system reliability under extreme HP/HT conditions. Collaboration with Shell and adherence to stringent insulation and performance requirements further ensured the pipeline’s performance.