The Challenge
A re-development at this scale is a routing and interface problem before it is an engineering problem. 300 km of pipelines, 150 km of umbilicals and 110 km of high-voltage subsea power cables share a congested Arabian Gulf seabed with existing infrastructure, crossings, shipping lanes and shallow-water constraints.
The shore approach was the critical decision. HDD, micro-tunnelling and open-cut each carried different cost, schedule, environmental impact and failure-mode profiles, and the choice would shape both the construction programme and the permitting case.
Our Approach
Three shore-crossing methods, developed to the same level of definition — so the comparison meant something.
VORYX team members led the subsea scope through FEED, covering route selection, crossing design, stability and burial requirements, and the interface between the pipeline, umbilical and power cable corridors.
The three shore-crossing methods were carried in parallel to a common level of definition and then compared on constructability, ground and geotechnical risk, environmental footprint, schedule and cost — so the selection was made on comparable evidence rather than on the option that happened to be developed furthest.
A CO₂ pipeline study was carried within the same FEED, addressing dense-phase transport requirements and how a CO₂ system would coexist with the hydrocarbon and power infrastructure in the same corridor.
What We Delivered
- Subsea FEED across 300 km of pipelines and 150 km of umbilicals
- 110 km high-voltage subsea power cable routing and installation basis
- Route selection, crossing design and seabed intervention strategy
- On-bottom stability and burial requirement assessment
- Shore-crossing option study — HDD, micro-tunnelling and open cut
- CO₂ pipeline study within the same corridor
- Installation methodology, vessel selection and constructability review
The Outcome
- FEED-level definition across the full subsea corridor
- Shore-crossing method selected on a like-for-like evidence base
- Installation strategy validated against available vessel capability
- CO₂ transport pathway assessed alongside the hydrocarbon scope
Standards Applied
- DNV-ST-F101
- DNV-RP-F109
- DNV-RP-F110
- DNV-RP-F401
- DNV-RP-F104
- IEC 63026
Operator and project names are anonymised for confidentiality and disclosed on request. Experience described is that of VORYX team members.
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