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This book offers readers a comprehensive overview, and an in-depth understanding, of suitable methods for quantifying and characterizing saline aquifers for the geological storage of CO2. It begins with a general overview of the methodology and the processes that take place when CO2 is injected and stored in deep saline-water-containing formations. It subsequently presents mathematical and numerical models used for predicting the consequences of CO2 injection. This book provides descriptions of relevant experimental methods, from laboratory experiments to field scale site characterization and techniques for monitoring spreading of the injected CO2 within the formation. Experiences from a number of important field injection projects are reviewed, as are those from CO2 natural analog sites. Lastly, the book presents relevant risk management methods. Geological storage of CO2 is widely considered to be a key technology capable of substantially reducing the amount of CO2 released into the atmosphere, thereby reducing the negative impacts of such releases on the global climate. Around the world, projects are already in full swing, while others are now being initiated and executed to demonstrate the technology. Deep saline formations are the geological formations considered to hold the highest storage potential, due to their abundance worldwide. To date, however, these formations have been relatively poorly characterized, due to their low economic value. Accordingly, the processes involved in injecting and storing CO2 in such formations still need to be better quantified and methods for characterizing, modeling and monitoring this type of CO2 storage in such formations must be rapidly developed and refined.

Field carbon dioxide injection experiments are necessary for demonstration, increasing the scientific understandingand quantification of the relevant processes occurring during geological storage in deep saline aquifers. As part ofthe large scale EU-FP7 project MUSTANG, a carbon dioxide injection experiment is to be carried out at the Heletzsite, Israel. Estimating the well head conditions is an important part of planning the experiment and an approach ispresented here for determining wellhead conditions needed to ensure that at least a specified flow rate is providedto the formation, given target layer conditions, while still respecting pressure buildup constraints. The main partof the study combines the multiphase flow in the target layer using the well known TOUGH2/ECO2N model, withthe flow in the injection pipe solving the 1D steady, real gas, augmented Euler equation. The Matching is carriedon in a two-stage process.The second part consists of a transient simulation of the combined well-reservoir flowusing the new T2WELL software for the same parameters. Preliminary conclusions of the comparison of the twostrategies are derived. Sensitivity analyses were carried out with respect to target layer properties and to pipe modelassumptions., MUSTANG

Highly controlled field injection experiments are necessary for demonstration, for scientific understanding and for quantification of the relevant processes of CO2 geological storage. The preparation of such an experiment requires reliable information on both the hydraulic, thermal and chemical properties of the target layer and the formation fluid as well as on the injection discharges and their associated pressure build-up in the reservoir. For this, there is a need to determine the state variables of CO2 in the injection tube near the well head, which can produce the desired mass flow rates given the condition at the reservoir, while respecting pressure buildup constraints. A model connecting the multiphase flow and transport processes in the target layer (based on the well-known TOUGH2/ECO2N model) at the vicinity of the injection well with those occurring in the injection tube (solving the one dimensional equations mass, momentum and energy conservation) has been developed. To this model the injection tube is a boundary condition. Once the reservoir pressure build-up resulting from the injection discharge is known, there is a need to determine the necessary injection conditions at the wellhead. For this purpose we apply the 1-D tube model, which provides the solution of the conditions in the injection pipe, given the injection rate and the pressure at the reservoir. These two linked models, the porous medium model and the pipe model, are applied to the planning of the Heletz injection experiment to be carried out in the frame of the EU-FP7 funded MUSTANG project. Sensitivity analyses are carried out with regard to uncertainty in the target layer permeability and the temperature of the injected CO2, which depends on the thermal heat transfer coefficient in the injection tube., Geophysical Research Abstracts, Vol. 13, EGU2011-6101, 2011, MUSTANG