Modelling pH evolution in Boom Clay porewater during in situ heating

摘要

During an in situ thermal perturbation on a clayey rock, CO2 production by decomposition of immature, labile kerogen can take place and acidify the porewater. Calculation of pH changes during five years of heating in the CERBERUS project (a demonstration test to study the near-field effects of a high level radioactive waste canister in an argillaceous formation) is carried out, using a coupled production-diffusion model, combined with or without chemical reaction with calcite. Re-equilibration time of the water-rock system is evaluated and perspectives are given for further developments in the frame of research for disposal of heat-emitting waste in a clay formation.