A pore-scale study of fracture sealing through enzymatically-induced carbonate precipitation (EICP) method demonstrates its potential for CO storage management.

Geological fractures are mechanical breaks in subsurface rock volumes that provide important subsurface flow pathways. However, the presence of fractures can cause unwanted challenges, such as gas leakage through fractured caprocks, which must be addressed. In this study, the dynamics of enzymatically induced carbonate precipitation in rock fractures and their subsequent influence on CO leakage were investigated from a pore-scale perspective for the first time.

An Improved Method for Determining Urease Activity from Electrical Conductivity Measurements.

We present an improved approach to evaluating the activity of urease from electrical conductivity (EC) measurements. In this approach, chemical equilibrium modeling via PHREEQC is used in conjunction with empirical equations for computing EC to develop a function that relates the increase in EC during urea hydrolysis in a closed reactor to the concentration of ammonium species present (and concentration of urea remaining) in the reaction solution. By applying this function to data from continuous measurement of EC during urea hydrolysis, we obtain a profile of the concentration of the urea substrate with time, which is then used to determine the urease activity.

Biocementation of soils of different surface chemistries via enzyme induced carbonate precipitation (EICP): An integrated laboratory and molecular dynamics study.

Biocementation is a ground improvement technique that involves precipitating a mineral (commonly calcium carbonate, CaCO) in the soil pore space to bind soil particles, in turn increasing the strength and reducing the permeability of the soil. Ureolysis (i.e.

Enzyme Induced Biocementated Sand with High Strength at Low Carbonate Content.

Specimens of silica sand treated via enzyme induced carbonate precipitation (EICP) showed surprisingly high strength at a relatively low carbonate content when non-fat powdered milk was included in the treatment solution. EICP is a biologically-based soil improvement technique that uses free urease enzyme to catalyze the hydrolysis of urea in an aqueous solution, producing carbonate ions and alkalinity that in the presence of calcium cations leads to precipitation of calcium carbonate. The strength achieved at less than 1.