CO2RINACopyright: © LIH
Funding: Federal Ministry of Education and Research, DFG
Program: Special Program Geotechnologies
Project term: 2011 to 2014
Risk-assessment of underground CO2 storage is often based on expert knowledge in order to evaluate individual storage-scenarios. Depending on personal expertise, events and processes may pose safety risks, environmental threats or health dangers. The disadvantage of this methodology is given by the subjectivity of the decision maker. Stochastic methodologies offer a more future oriented strategy. They support the reduction of complex models under use of process modelling and lay the foundations for Monte-Carlo simulations. The main task of the present project thus focuses the development of stochastic methodologies for CO2 storage relevant space scales under integration of the following main sub aspects:
● pressure regime and mass flow in storage formations
● migration of fluids from storage formations into overlying layers via different pathways
● impact of CO2 injections on the surrounding groundwater regime
● atmospheric CO2 emissions
The present project aims at the development and numerical implementation of a broad applicable risk analysis tool for CO2 storage in deep reservoirs. Independency of site-specific boundary conditions and flexibility for individual target-sites mark major objectives within the development of this tool. The present approach thus respectively focuses on a better process-transparency, which is needed for both, proper site selection as well as approval procedures.
The challenge of CO2 risk analysis is given by the problem to assess the probability of a single / coupled process contribution to bulk CO2 migration into near surface layers as well as to bulk atmospheric CO2 emissions. In this context conceptual uncertainties (main control processes), parameter uncertainties (process parameters and parameter variabilities bear an inherent fuzziness as a result of the natural heterogeneity of geological subsoils) and parameter variabilities have to be considered as potential control factors. Many of these factors need to be analysed under use of deterministic approaches. With regard to the overall risk analysis tool however a probabilisitic procedure is inevitable to validate the parameter variabilities and uncertainties.
In view of previous existing international risk approaches the current approach highlights a strict modular hierarchical structure under use of predefined interfaces. This strategy offers the possibility to couple and integrate previous site specific models into the present risk assessment tool development. Single modules feature the possibility to be extended separately and can be interchanged with other modules if necessary.