An Integrated CCS Model Chain

Abstract

Two major CCS projects, PORTHOS and ARAMIS, in The Netherlands are progressing towards final investment decision. CO2 captured from industrial clusters connected to a pipeline network will feed CO2 into multiple offshore depleted gas reservoirs with multiple wells in the Dutch sector of the North Sea.

Feasibility studies have matured the transport and storage system and demonstrated the challenges of injecting cold CO2 into hot deep and low pressure (depleted) reservoirs. CO2 properties change dramatically over small changes in pressure and temperature in the reservoir, well and pipeline exacerbated by Joule-Thomson cooling. Undesired effects in the near wellbore zone could be hydrate formation diminishing injectivity, geomechanical effects induced by thermal stresses leading to fracturing causing an increase in injectivity or possible threats to well integrity. In the far field there may be effects on fault stability (depleted gas fields are often fault-bounded). Understanding the physics, the links between transport and storage, as well as the uncertainties are required when assessing safety of operations. It is clear that coupled-simulations involving fluid flow, heat transport, geomechanical effects in pipelines and wells and porous media are necessary.

Operating such a complex multi-element system with complex behavior and honoring uncertainty in the various elements requires a clear workflow and a modelling strategy and toolbox, i.e. an integrated CCS model chain (ICCSMC). Such a toolkit should provide all relevant models honoring their links and uncertainties (e.g. through a large model ensemble) to support storage operations and strategic CCS operator decisions.

Here we present a schematic/workflow concept that represents this ICCSMC and show how its elements can be selected to drive a model chain to obtain from given input outcomes that support specific decisions. Four examples are shown for the processes of optimisation, data assimilation, conformance assessment and a-priori conformance assessment for monitoring design.

Keywords: integrated CCS workflow, model chain, model applications