Insights

Jee Extends Life of North Sea Subsea Infrastructure with Advanced Integrity Management

Written by Jee Ltd | Jul 21, 2025 1:21:20 PM

Jee Ltd, a leading subsea engineering consultancy, has successfully completed a life extension (LTE) assessment for two critical subsea flowlines in the North Sea, reinforcing its position as a trusted partner in offshore integrity management.

As the global energy sector evolves to meet decarbonisation targets and extend the lifecycle of offshore assets, integrity management has become essential to safe and sustainable operations. Jee’s latest project highlights how strategic engineering can unlock continued production from ageing infrastructure while deferring costly decommissioning.

Project Overview

The project involved two 10-inch looped flowlines connected to a floating production storage and offloading (FPSO) unit. Originally designed for a 10-year service life, the pipelines were approaching the end of that period. With production still active and further economic recovery possible, the operator engaged Jee to assess the feasibility of extending the system’s operational life.

Standards-Led Approach

Jee’s assessment was guided by internationally recognised standards, including:

  • ISO/TS 12747 – Integrity management of pipelines for extended use
  • NORSOK Y-002 – Life extension of subsea production systems
  • DNV-RP-F116 – Integrity management of submarine pipeline systems

The evaluation followed a five-stage methodology: defining LTE requirements, reviewing operational history, identifying degradation mechanisms, conducting risk-based assessments, and recommending inspection and monitoring strategies.

Key Findings and Outcome

Jee developed a comprehensive Basis of Analysis (BoA) and conducted a detailed integrity review using Pipeline Integrity Management System (PIMS) data. A tailored Risk-Based Inspection (RBI) strategy was implemented to address threats such as internal corrosion and mechanical damage.

The assessment concluded that both flowlines could safely operate until 2030, contingent on the implementation of specific mitigation measures. Internal corrosion was identified as the life-limiting factor for one pipeline, with conservative assumptions guiding the extension decision.

A Model for Responsible Offshore Operations

“This project exemplifies how rigorous, standards-driven integrity management can extend the life of critical subsea infrastructure,” said a spokesperson for Jee Ltd. “By combining technical depth with real-world operability, we help operators maximise asset value while maintaining safety and environmental stewardship.”

As operators across the UK Continental Shelf (UKCS) and beyond seek to optimise existing infrastructure, Jee continues to deliver clarity and confidence through its lifecycle extension services.

For more information, visit www.jee.co.uk/integrity-management

To contact our Head of Integrity Management, Graham Wilson, email graham.wilson@jee.co.uk, or call +44 (0)1732 371 371.