title: Detecting Microbially Induced Calcite Precipitation in a Model Well-Bore Using Downhole Low-Field NMR.
abstract: Microbially induced calcite precipitation (MICP) has been widely researched recently due to its relevance for subsurface engineering applications including sealing leakage pathways and permeability modification. These applications of MICP are inherently difficult to monitor nondestructively in time and space. Nuclear magnetic resonance (NMR) can characterize the pore size distributions, porosity, and permeability of subsurface formations. This investigation used a low-field NMR well-logging probe to monitor MICP in a sand-filled bioreactor, measuring NMR signal amplitude and T2relaxation over an 8 day experimental period. Following inoculation with the ureolytic bacteria, Sporosarcina pasteurii, and pulsed injections of urea and calcium substrate, the NMR measured water content in the reactor decreased to 76% of its initial value. T2relaxation distributions bifurcated from a single mode centered about approximately 650 ms into a fast decaying population (T2less than 10 ms) and a larger population with T2greater than 1000 ms. The combination of changes in pore volume and surface minerology accounts for the changes in the T2distributions. Destructive sampling confirmed final porosity was approximately 88% of the original value. These results indicate the low-field NMR well-logging probe is sensitive to the physical and chemical changes caused by MICP in a laboratory bioreactor.
authors.affiliation: Center for Biofilm Engineering, Montana State University , Bozeman, Montana 59717, United States.|Department of Chemical and Biological Engineering, Montana State University , Bozeman, Montana 59717, United States.
authors.forename: Catherine M
authors.initials: CM
authors.lastname: Kirkland
authors.affiliation: Center for Biofilm Engineering, Montana State University , Bozeman, Montana 59717, United States.
authors.forename: Sam
authors.initials: S
authors.lastname: Zanetti
authors.affiliation: Vista Clara Inc. , 12201 Cyrus Way Ste. 104, Mukilteo, Washington 98275, United States.
authors.forename: Elliot
authors.initials: E
authors.lastname: Grunewald
authors.affiliation: Vista Clara Inc. , 12201 Cyrus Way Ste. 104, Mukilteo, Washington 98275, United States.
authors.forename: David O
authors.initials: DO
authors.lastname: Walsh
authors.affiliation: Center for Biofilm Engineering, Montana State University , Bozeman, Montana 59717, United States.|Department of Mechanical and Industrial Engineering, Montana State University , Bozeman, Montana 59717, United States.
authors.forename: Sarah L
authors.identifier: 0000-0003-3859-8565
authors.initials: SL
authors.lastname: Codd
authors.affiliation: Center for Biofilm Engineering, Montana State University , Bozeman, Montana 59717, United States.|Department of Civil Engineering, Montana State University , Bozeman, Montana 59717, United States.
authors.forename: Adrienne J
authors.initials: AJ
authors.lastname: Phillips
mesh_terms: D002119:Calcium Carbonate / Q000737:chemistry*; D008279:Magnetic Resonance Imaging; D009682:Magnetic Resonance Spectroscopy; D016062:Porosity; D058644:Sporosarcina / Q000378:metabolism*
chemical_list: D002119:Calcium Carbonate