There is no doubt that greenhouse gas emissions, particularly CO2, needs to be reduced to mitigate the effects of climate change. While carbon management can be achieved through a number of technological and engineering approaches ranging from energy efficiency (i.e., highly energy integrated system and process intensification) to renewable energy (wind, solar, hydrogen), CO2 capture & storage (CCS) has been identified as having a key role in the energy transition.
Captured anthropogenic CO2 can be permanently stored in saline aquifers and depleted reservoirs. Saline aquifers (normally unsuitable for industrial or human exploitation) offer the largest storage capacity; however, there is, usually, lack of geological characterization leading to high risks due to large uncertainty. On the other hand, depleted gas fields, close to economical life cessation, are deemed an excellent alternative as safe and long-term storage is already proven and immense geological characterisation has been gathered during production life. Moreover, there is great potential to repurpose the existing offshore infrastructure (pipelines, platforms, and wells) as to minimize capital expenditure and delaying decommissioning costs. Repurposing existing production systems can also be an efficient way to achieve rapid deployment of CCS at large scale.
In this paper, we present the key engineering challenges, risks, and opportunities in the re-use of existing oil and gas offshore infrastructure for CO2 transport and injection. We highlight the complex operational constraints and interactions between different components of the transportation network. The design and operation of the transportation network is governed by the following drivers:
Robust and flexible operation
Minimize cost (or delay expenditure as long as possible)
Minimize emissions of greenhouse gases associated to the operation of the transport network (i.e., energy efficiency)
Start operation with minimum modifications