Technical Committee Reservoir Engineering

Impedance Spectroscopy for Assessing the Wetting Conditions of Reservoir Rocks

The wetting conditions of reservoir rocks influence important reservoir characteristics like relative permeabilities, residual oil or water saturation. In this project we studied, if Impedance Spectroscopy (IS) can provide a characterization of the wetting state.

We first examined numerical model systems of water filled connected pores considering the electrical double layer at the fluid rock interface. The resulting understanding of the system was used to design an experimental study, conducted on a reference system of sintered borosilicate samples. These experiments were conducted in parallel with measurements on reservoir rocks, which conclude our study.

Both the numerical simulation and the measurements on synthetic samples show that qualitative wettability information can be derived from IS data for sufficiently fine pored rock with low saline pore water. The presence of IS effects in low saline environments can be confirmed for reservoir rocks, allowing for an application e.g. in the context of “low salinity flooding”, even though not for high salinity reservoir conditions.