Fossil Fuel Bioprocessing projects
Geophysical Characterization of Microbial Activity in Reservoir Rocks
Geophysical monitoring methods can potentially provide data, including the spatial extent of biological activity, which is crucial for microbially enhanced hydrocarbon recovery (MEHR). This project evaluated how bacterial activity alters the rock’s mechanical and/or transport properties and investigated whether such induced property changes are large enough to be measured in the field.
Researchers completed integrated measurements of seismic response and permeability reduction during MEHR treatment using model organism Leuconostoc mesenteroides. Results indicate that rapid clogging by biopolymers generates an increase in seismic attenuation in the ultrasonic regime. This confirms that time-lapse seismic attenuation tomography is the best method for initial field tests requiring the spatial monitoring of biopolymer distribution. Ajo-Franklin’s lab also completed secondary measurements of the seismic response of L. mesenteroides-generated biopolymers in batch systems; lack of response indicated biopolymer/frame interactions are responsible for attenuation.
Researchers developed and tested a system for making 1-2 khz seismic resonance measurements of core samples. The system allows mid-frequency velocity and attenuation measurements on small (1.5” OD) cores during amendment treatment and microbial growth. Ajo-Franklin’s group performed MEHR core-flood experiments during which rapid permeability reduction and an increase in P-wave attenuation were observed. These results suggest that time-lapse Q-tomography may be a viable approach for monitoring field MEHR treatments.
Ajo-Franklin’s group is exploring geophysical questions related to MEHR and working to leverage the resulting high P/T experimental platform to aid other groups within EBI in investigating related systems at in situ conditions.
Published in 2011
Seismic Monitoring of Permeability Reduction Due to Biopolymer Formation in Unconsolidated Materials, Tae-Hyuk Kwon, Jonathan Ajo-Franklin, 2011, SEG Expanded Abstracts, Vol. 30, pp. 2282, doi:10.1190/1.3627663, 2011.