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.
Original language | English |
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Number of pages | 6 |
DOIs | |
Publication status | Published - 29 Jun 2022 |
Event | 56th US Rock mechanics/Geomechanics Symposium: ARMA - New Mexico/Online, US Duration: 26 Jun 2022 → 29 Jun 2022 |
Conference
Conference | 56th US Rock mechanics/Geomechanics Symposium |
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City | US |
Period | 26/06/22 → 29/06/22 |
Keywords
- calcite precipitation
- anhydrite fractures
- gouges
- microbial-induced-calcite-precipitation (MICP)
- sealing