Microbially induced calcite precipitation for sealing anhydrite fractures with gouges

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Sang, Guijie and Lunn, Rebecca and Minto, James M. and El Mountassir, Grainne (2022) Microbially induced calcite precipitation for sealing anhydrite fractures with gouges. In: 56th US Rock mechanics/Geomechanics Symposium, 2022-06-26 - 2022-06-29, New Mexico/Online. (https://doi.org/10.56952/ARMA-2022-0277)

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Abstract

Caprock formation forms a natural barrier for geological storage of CO2, nuclear wastes, and hydrocarbon resources. Fault and natural/artificial fractures that crosscut the storage systems represent potential leakage pathways. Sealing of caprock fractures/faults is of great importance to ensure its long-term sealing integrity. In this study, we conduct microbial-induced-calcite-precipitation (MICP) experiments for sealing anhydrite fractures (artificially cut) with gouges. MICP involves a bio-chemical reaction for calcite precipitation using ureolytic microorganism - Sporosarcina pasteurii. The precipitated calcite, which occurs initially from finer pores to larger pores, induces a 10.7% decrease of porosity inside the fracture after the 1st 12 cycles of MICP treatment. After 18-21 cycles of MICP treatment, the fracture permeability of the two fractured core samples effectively decreases by 2-3 orders of magnitude. Our study also indicates that the MICP sealing efficiency could be improved by lowering the injection rate, optimizing fluid chemistry for a better bacteria retention inside the fracture. The study provides a baseline for using MICP technique to seal anhydrite fractures.

ORCID iDs

Sang, Guijie ORCID logoORCID: https://orcid.org/0000-0002-2379-7521, Lunn, Rebecca ORCID logoORCID: https://orcid.org/0000-0002-4258-9349, Minto, James M. ORCID logoORCID: https://orcid.org/0000-0002-9414-4157 and El Mountassir, Grainne ORCID logoORCID: https://orcid.org/0000-0003-4213-8182;
CORE (COnnecting REpositories)