- significantly advance our knowledge of specific processes that could influence the long-term fate of geologically stored CO2
- yield validated tools for predicting long-term storage site performance.
ULTimateCO2, a four-year collaborative project financed by the 7th Framework Programme and coordinated by BRGM, aims to shed more light on the long-term processes associated with the geological storage of CO2.
ULTimateCO2 unites 12 partners (research institutes, universities, industrialists) and a varied panel of experts (NGOs, national authority representatives, IEAGHG, ….).
Based on a multidisciplinary approach, and bringing together laboratory experiments, numerical modelling and natural analogue field studies, ULTimateCO2 will increase our understanding of the long-term effects of CO2 Capture and Storage (CCS) in terms of hydrodynamics, geochemistry, mechanics of the storage formations and their vicinity.
Understanding long-term processes at storage-site scale
The project considers the three crucial elements of a storage site:
- Reservoir: All processes of multiphase flow and associated geochemical reactivity are studied through laboratory experiments and digital modelling in order to assess CO2 trapping mechanisms (structural, dissolution, residual, mineral), based on both hypothetical and real data.
- Caprock: A shaly caprock, potentially faulted or fractured, is studied in detail based on i) previous data on gas reservoirs in the North Sea that have shown leakage, ii) laboratory tests on shale cores altered by geochemical acidification, and iii) numerical modelling coupling geochemical alteration of shale and behaviour mechanics.
- Wellbore: The wellbore vicinity is a crucial zone for possible leakage compromising the long term efficiency and safety of a storage site. The project is undertaking a true scale experiment in the underground rock laboratory of Mont Terri in Switzerland to reproduce conditions of a well bottom in contact with brine acidified by dissolved CO2 during one year, with fluid sampling and continuous monitoring of permeability of the shale-cement-casing interface. Overcoring and extraction of the entire system will then enable detailed identification of any potential leakage paths and geochemical interactions of the interfaces.
Integration of storage-site results at basin scale
- impact studies on basin hydrogeology and brine displacement with construction of a 3D model of the Paris Basin and the Southern part of the North Sea Bunter Sandstone Formation,
- numerical modelling of fault reactivation,
- characterisation of the impact of CO2 leakage through wells,
- development of upscaling methods for numerical simulations of large-scale geometries.
The study of such highly complex processes on time scales stretching to several thousands of years must be accompanied by an assessment of the associated uncertainties. The predictions resulting from the numerical models will be analysed using different approaches (epistemic or bayesian) in order to accurately estimate the errors associated with the simulations carried out to predict the long-term behaviour of a CO2 storage reservoir.
Guidelines and dissemination
The project will draw up a set of guidelines on the long-term performance of a storage site, particularly aimed at operators and legislators. The scientific findings will also be disseminated to a variety of target audiences including the scientific community, national authorities, storage developers, investors and NGO’s and the general public, so as to increase understanding and build confidence in this technology to fight against climate change by reducing our greenhouse gases.
The project considers in detail the 3 crucial elements of a storage site: the reservoir, caprock and wellbore vicinity
These results are then merged and transposed to a 3D model at basin scale to take into account the entire CO2 storage complex
Dernière mise à jour le 13.10.2015