Risks Mitigation and Performance Optimization of CCS Projects Through Integrated Production Modelling and Life of Field Simulations

Abstract Carbon Capture and Storage (CCS) projects often entail transport of captured effluent gases through long distances to offshore storing sites. In upcoming, planned projects in the North Sea and worldwide, this is achieved through transport in subsea trunklines that can cover hundreds of kilometers. To achieve the flow required, large compression stations are installed upstream of the trunkline inlet to compress the CO2 mix to dense phase. However, the expected size and complexity of these projects, involving several industrial emitters, shipping and terminal operators, and various operators of the offshore platforms in charge of injecting the fluid into subsurface stores, combined with a different operator of the offshore trunkline, presents unprecedented challenges. We analyze the performance of a hypothetical configuration of such a project and test its resilience against potential scenarios, including upsets such as the shutdown of one or more emitters or the temporary unavailability of one or more storage platforms. Through a life of the field integrated production model, combining surface facilities and subsurface storage, we explore how the variations of the turndown, induced by varying nominations and allocations to different emitters and storing sites, may affect the operating envelope over time. This gives a clear view of the feasibility of the operations various scenarios. Through a detailed compositional modelling approach, we look at the risks associated with the occurrence of liquid dropout, corrosion, formations of solid phases, and explore the thermal constraints to test the optimal operating conditions and their modifications, over the life of the asset. We demonstrate that, to mitigate the risks of unexpected upsets, the delicacy of the network balance, and the complexity of the project, a careful analysis of the impacts of each engineering and operating choice is required. At the same time, our study also shows how the high-fidelity analysis of the upset requires the adoption of an integrated, life of field, modelling approach, due to the tight thermohydraulic coupling of the subsurface storage with the network transport facilities, and the continuous evolution of the operating conditions, determined by the filling up of the reservoirs.