Case Study

Storing CO2 in depleted gas reservoirs beneath the North Sea

3D illustration of an underwater gas pipeline.

How we delivered a safe and feasible design for Porthos (Port of Rotterdam CO2 Transport Hub and Offshore Storage). Porthos will transport CO2 from industries in Rotterdam to depleted gas fields beneath the North Sea. The project will store around 37 million tons of CO2 with the aim to inject 2.5 million t/year over a 15-year lifespan.

Storing CO2 beneath the sea is a method to prevent large amounts of CO2 from getting into the atmosphere in the short term at relatively low costs.

Under the Porthos consortium, EBN, Gasunie and Port of Rotterdam Authority plan to transport and store CO2 from various industrial emitters in the Port of Rotterdam area.

Expertise in offshore pipelines to deliver a safe and feasible design

Our Intecsea and Worley teams completed the conceptual and pre-FEED studies for the project. This involved selecting the main equipment for the onshore compressor station and the offshore pipeline system, including mechanical design and flow assurance. We also delivered the FEED for the offshore pipeline that will transport CO2 to storage.

The interface between pipeline design and injection well/reservoir management was a key challenge. Our design had to address complexities around injecting CO2 into low-pressure reservoirs beneath the seabed by focusing on preventing ductile fractures in the pipeline.

From feasible design to implementation

Our design will help transport the CO2 via a low-pressure pipeline before pressurizing it in a compressor station so that it can travel 20 km offshore in a high-pressure pipeline. The CO2 will arrive at a platform where it's injected into depleted gas fields, more than 3 km below the North Sea seabed. The Porthos infrastructure is expected to be operational from 2024.

With an integrated approach, alignment and collaboration with our client we delivered a cost-effective design. We’re now serving as Owner’s Engineer as the project moves forward to implementation.

It’s a pleasure to support this first-of-a-kind project. Capturing CO2 is an important step to reaching net-zero targets and a key component of the Netherlands’ decarbonization strategy.

Ping Liu - Managing Director, Intecsea

Learn more about the Porthos project here.