Water in natural environments consists of many ions. Ions are electrically charged and exert electric forces on each other. We discuss whether the electric forces are relevant in describing mixing and reaction processes in natural environments. By comparing our computer simulations to lab experiments in literature, we show that the electric interactions between ions can play an essential role in mixing and reaction processes, in which case they should not be neglected in numerical modeling.

Fluid injection in a geologic layer shifts pressure and stress conditions and may trigger the reactivation of pre-existing faults. We present an approach to describe changes in the stress-field upon such an induced seismic event by applying characteristic stress-drop terms based on reported literature values for a great variety of earthquakes, even at very different magnitudes. The article illustrates exemplary results and discusses also the effect of permeability on expectable seismicity.

In the context of hydraulic fracturing we constructed a comprehensive FEP database and applied it to six key focused scenarios defined under the scope of FracRisk project (www.fracrisk.eu). The FEP database is ranked to show the relevance of each item in the FEP list per scenario. The main goal of the work is to illustrate the FEP database applicability to develop a conceptual model for regional-scale stray gas migration.

Stakeholder participation in numerical modeling of brine migration due to injection of CO₂ into deep saline aquifers is tested in this work. Part 1 reports the process of participatory modeling in the development of a numerical model and Part 2 discusses essential technical findings obtained through this model, showing that notable increases in salt concentrations are confined to regions where they were already high a priori and where barrier layers are discontinuous.

Stakeholder participation in numerical modeling of brine migration due to injection of CO₂ into deep saline aquifers is tested in this work. Part 1 reports the process of participatory modeling on the development of a numerical model and Part 2 discusses essential technical findings obtained through this model showing that notable increases in salt concentrations are confined to regions where they were already high a priori and where barrier layers are discontinuous.