When pH and alkalinity increase, calcite frequently precipitates and hence modifies the petrophysical properties of porous media. The complex conductivity method can be used to directly monitor calcite precipitation in porous media because it is sensitive to the evolution of the mineralogy, pore structure and its connectivity. We have developed a mechanistic grain polarization model considering the electrochemical polarization of the Stern and diffuse layers surrounding calcite particles. Our complex conductivity model depends on the surface charge density of the Stern layer and on the electrical potential at the onset of the diffuse layer, which are computed using a basic Stern model of the calcite/water interface. The complex conductivity measurements of Wu et al. on a column packed with glass beads where calcite precipitation occurs are reproduced by our surface complexation and complex conductivity models. The evolution of the size and shape of calcite particles during the calcite precipitation experiment is estimated by our complex conductivity model. At the early stage of the calcite precipitation experiment, modelled particles sizes increase and calcite particles flatten with time because calcite crystals nucleate at the surface of glass beads and grow into larger calcite grains. At the later stage of the calcite precipitation experiment, modelled sizes and cementation exponents of calcite particles decrease with time because large calcite grains aggregate over multiple glass beads and only small calcite crystals polarize.

Wettability is a critical interface property for two-phase flow and reactive transport process in porous media. Wettability alteration is considered as the dominated mechanism for enhanced oil recovery during low salinity waterflooding. The conventional characterization of wettability by contact angle at a single substrate and Amott method at core are limited. In this minireview, we introduce recent improvements in characterization of the electrochemical properties of an interfacial layer formed at the mineral-water interface, and review the application of surface potential (i.e., zeta potential) as an invasive and reliable technique to characterise the wetting behaviour of sample core across different geochemistry conditions. In order to resolve the puzzle of the wettability alteration in an oil-brine-rock system, experimental studies combined with numerical simulations across multiscale and variable geochemistry conditions are required for the future investigation.