Experimental and numerical investigations into CO2 interactions with well infrastructure and its impact on long term well integrity

Research presented in this paper investigated the sealing behaviour of the microannulus at cement-casing interface under simulated subsurface reservoir pressure and temperature conditions and used the experimental findings to develop a methodology to assess the overall integrity of the wellbore region during CO2 storage. A full scale wellbore experimental test set up was constructed for use under elevated pressure and temperature conditions encountered in typical CO2 storage sites. Three test cases representing different reservoir depth, temperature and brine salinities were analysed through long term experiments with continuous flow of CO2 through the microannulus. Relationships for the reduction in permeability of the microannulus with time were derived from the experimental data for use in reservoir simulations on a realistic reservoir model for all three scenarios to assess the impact of leakage from the wellbore casing and cement interface on integrity of CO2 storage. (C) 2014 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/).