A Field and Modeling Study of Fractured Rock Permeability Reduction Using Microbially Induced Calcite Precipitation

Abstract

Microbially induced calcite precipitation (MICP) offers an attractive alternative to traditional grouting technologies for creating barriers to groundwater flow and containing subsurface contamination, but has only thus far been successfully demonstrated at the laboratory scale and predominantly in porous media. We present results of the first field experiments applying MICP to reduce fractured rock permeability in the subsurface. Initially, the ureolytic bacterium, Sporosarcina pasteurii, was fixed in the fractured rock. Subsequent injection of cementing fluid comprising calcium chloride and urea resulted in precipitation of large quantities (approximately 750 g) of calcite; significant reduction in the transmissivity of a single fracture over an area of several m(2) was achieved in around 17 h of treatment. A novel numerical model is also presented which simulates the field data well by coupling flow and bacterial and solute reactive transport processes including feedback due to aperture reduction via calcite precipitation. The results show that MICP can be successfully manipulated under field conditions to reduce the permeability of fractured rock and suggest that an MICP-based technique, informed by numerical models, may form the basis of viable solutions to aid pollution mitigation.

A revised model for microbially induced calcite precipitation: Improvements and new insights based on recent experiments

“…Models for simulating MICP processes have been developed by a number of authors [ Martinez et al ., ; Barkouki et al ., ; Cuthbert et al ., ; van Wijngaarden et al ., , 2013; Ebigbo et al ., ], each of the models focusing on different processes. Often, the models developed are designed to match a series of experiments.…”

“…In Cuthbert et al . [], a first‐order kinetic model is assumed for ureolysis, and bacterial transport and attachment are modeled. The precipitation rate is assumed to be stoichiometric to the ureolysis rate.…”

Fracture sealing by mineral precipitation: The role of small‐scale mineral heterogeneity

“…However, in many subsurface environments, fluid-rock interactions lead to mineral precipitation, which can significantly reduce fracture permeability. This fracture sealing process can have the desired effect of enhancing the ability of geologic seals to isolate, for example, overpressurized CO 2 [Huerta et al, 2013;Matter et al, 2016], hydrocarbons [Boles et al, 2004], or hydrothermal fluids [Chaudhuri et al, 2012] and may be enhanced by microbial processes in efforts to isolate contaminants [Cuthbert et al, 2013;Mountassir et al, 2014]. On the other hand, precipitation-induced permeability reduction within fault zones limits dissipation of increasing pore pressures, which can result in the undesired effect of more frequent seismic events [Audet and Burgmann, 2014;Yarushina and Bercovici, 2013].…”

Microbially Induced Calcite Precipitation Employing Environmental Isolates

“…However, the rate of calcite precipitation by denitrification was lower than that by the urease process. A field and modeling study to seal the fractured rock were conducted using S. pasteurii , and a significant reduction in permeability was achieved over 17 h of treatment [17]. Furthermore, full-scale grouting of a gravel layer borehole was carried out using a number of technologies developed through laboratory testing [18,19,20].…”