PH como variável indicadora em águas subterrâneas de vazamentos provenientes de sequestro geológico de carbono

Abstract

Carbon geological sequestration has been pointed out as an important alternative for reducing atmospheric CO2 emissions. However, potential leaks from the storage formation can reach shallow freshwater aquifers and compromise their quality. The development of techniques for CO2 leak detection in shallow aquifers can assist in the prompt adoption of mitigation measures. The use of geochemical parameters as CO2 leakage detection can be a viable technique since groundwater may suffer significant variations in some geochemical parameters at very early stages of its contact with the CO2 . Thus, the aim of this work was to determine hydrogeochemical variables indicative of the interaction between CO2 and a limited reactivity aquifer to detect leaks from geological sequestration. To accomplish this purpose, a field leak simulation was performed through the controlled release of CO2 in the saturated portion of a limited reactivity aquifer. Groundwater was monitored by multilevel wells and physicochemical analyses. The results showed that pH variations can be indicative of leakage of CO2 from geological sequestration in limited reactivity aquifers and may be utilized in Measurement, Monitoring and Verification programs (MMV) of geologically sequestered CO2