Subsea Tie-Back FEED Peer Review

Project Phase

FEED Peer Review

Disciplines

Subsea Multidiscipline
Topside Interface

Location

UKCS

Service

Engineering Consultancy

Summary

Infinity delivered an independent, system-wide FEED peer review of our client’s UKCS located subsea tie-back to their existing asset. We identified 24 optimisation opportunities and up to 10–25% potential CAPEX reduction by challenging design assumptions across the system.

Overview

We were engaged by our client to deliver an independent FEED peer review of TechnipFMC’s proposed design for the subsea tie-back to a UKCS platform.

The objective was to challenge the FEED, confirm readiness for Execute, and critically identify cost-saving and optimisation opportunities with particular focus on the SURF and SPS scopes.

Infinity conducted a comprehensive, multidisciplinary assessment covering pipelines, umbilical, structures, installation, operability and future field considerations.

Objective

The objectives of the peer review were to:

Assess whether the FEED design was suitable to progress to Execute
Identify design optimisation opportunities and potential CAPEX/OPEX reductions
Highlight key technical and operability risks and propose mitigations
Benchmark subsea design choices and costs
Strengthen our client's internal technical assurance and investment decision case

Design Optimisations

10-25%

Percent CAPEX Reduction

£20m

CAPEX Savings

Key findings

While the design was technically workable, it was not considered ready for Execute and was assessed as sub-optimal in several key areas
Opportunities identified included corrosion allowance and wall-thickness optimisation (up to £9M saving), pressure derating (approx. £1.5M saving), and adoption of a HIPPS-protected concept (up to £12M saving). Further savings of ~£1.5M were identified through refinement of upheaval-buckling and rock-dump assumptions
Identified scope to remove unnecessary functionality, reduce system vulnerabilities and shrink associated structural footprints
Midline, UTA and SSIV structures were identified as over-engineered, with significant potential to reduce concrete volumes, fabrication scope and scour protection
The need, configuration and overall scope of the SSIV presented a major opportunity for reassessment and cost reduction

Differentiator

Infinity brought a truly independent, system-wide perspective, challenging embedded FEED assumptions across SURF, SPS and operability. By combining deep subsea engineering expertise with cost and constructability awareness, the review moved beyond assurance to unlock tangible CAPEX value while improving execution readiness.

In order to demonstrate the pipeline design optimisation savings Infinity brought in support from SINTEF to validate on-bottom-stability findings enabling firm recommendation for removal of base case conservatism in wall thickness.

Outcome

Infinity identified 24 optimisation opportunities across the subsea system, with the potential to reduce overall project CAPEX by 10–25% while improving design robustness and executability.

The peer review provided the client with a clear, evidence-based pathway to improve FEED maturity, optimise capital spend and progress the project with increased assurance and execution readiness.

Find Out More

Have questions about this project? Contact us to find out how Infinity can help to manage your subsea assets.

joao.conde@infinity-limited.com