| Time: |
June 18, 2015 |
| Lecturer: |
Robin Gerlach
Center for Biofilm Engineering, Montana State University, USA |
| Venue: |
Pfaffenwaldring 61, Raum U1.003 (MML), Universität Stuttgart
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| Download as iCal: |
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We recently completed a field-scale demonstration of the biomineralization sealing technology validating that microbially-induced calcium carbonate precipitation can be used to seal fractures in sandstone surrounding wells. This presentation will focus on the successful field demonstration completed in a well at the Gorgas Powerplant in Alabama (USA) but will also provide an overview of the experimental and modeling efforts completed prior to the demonstration. The field test consisted of the creation of perforations and fractures around the well at around 1116 ft below ground surface. Subsequently, a bailer delivery system was used to deliver the biomineralization sealing agents through the 2 7/8" well tubing and fluids were injected using a pulsed injection strategy over 4 days. On day 5, no significant amount of fluid could be injected anymore below the original fracturing pressure. The formation was finally re-fractured at a higher pressure than during the initial fracturing event.Overall, the results indicate that the biofilm-induced mineralization technology, reduced injectivity, increased the re-fracturing pressure and reduced the ability to inject fluids after re-fracturing. The rationale and success of the laboratory and modeling work leading up to the field demonstration will be summarized in the context of the field demonstration. This work consisted of micro- to meso-scale reactors, packed sand columns and core samples of up to 70 cm diameter operated at ambient and elevated pressures (>75 bar). Darcy-, pore network-, and pore-scale reactive transport models have been developed and guided the experimental and field-demonstration efforts. We (and others) have now developed biofilm and mineral precipitation strategies that can be engineered to manipulate porous media. We are in the process of engineering biofilm-induced mineral precipitation for the development of beneficial processes including bioremediation, enhanced oil recovery, abatement of saltwater intrusion, soil stabilization, and maintenance of well integrity.
