Resistivity-based pore pressure investigation using the Waxman-Smits equation in the North Alpine Foreland Basin, SE Germany

The Waxman-Smits equation can be used in combination with careful petrophysical and geological investigation of geophysical well logs to estimate subsurface shale pressures from electrical resistivity logs. The main benefit of this approach is the transferability between different wells, even across an entire sedimentary basin, once the normal compaction trend (NCT) is constrained. The main disadvantage is given by the dependency on a large number of factors, which, in the North Alpine Foreland Basin, might result in overestimation of pore pressures in some areas. Nevertheless, this further highlights the necessity of involving the local and regional geological boundary conditions in pore pressure studies. In the context of deep geothermal exploration in the overpressured North Alpine Foreland Basin in SE Germany, the results of this study are of particular relevance, since finding a reasonable trade-off between data acquisition and cost minimization is key to ensure economic deep geothermal projects. Utilizing data sources, which are already available and measured while drilling, to estimate subsurface pressures in overpressured target areas is therefore an important step forward to safe and economic deep geothermal exploration.