Microbes have a remarkable ability to adapt to the extreme conditions in fracking wells. Scientists led by researchers at Ohio State University found that microbes consume some of the chemical ingredients commonly used in the fracking process, creating new compounds which in turn support microbial communities below ground. The process allows the microbes to survive in very harsh environments that include very high temperatures, pressures, and salinity.
The work, based on samples from hydraulically fractured wells in Pennsylvania and Ohio, helps scientists understand the complex interactions among microbes -- important for understanding the planet's environment and subsurface. The findings also help scientists understand what is happening in fracking wells and could offer insight into processes such as corrosion.
The team studied microbes in fracking fluid from more than a mile and a half below the ground surface. Researchers measured the metabolic by-products excreted by the microbes, which can tell scientists what compounds the microbes are producing, where they are drawing energy from, and what they need to stay alive.
Using multiple samples drawn from the two wells over a 10-month period, the team identified 31 different microbes in fluids produced from hydraulically fractured shales. The team found that fractured shales contained similar microbial communities even though they came from wells hundreds of miles apart in different kinds of shale formations.
The complex mix -- with some microbes producing compounds that others use or feed upon -- produces some interesting outcomes. One particularly interesting compound, glycine betaine, is what allows the microbes to thrive by protecting them against the high salinity found in the wells. Other microbes can subsequently degrade the compound to generate more food for the bacteria that produce methane. Yet another process may produce substances that contribute to the corrosion of the steel infrastructure in wells.
The scientists even discovered a new strain of bacteria inside the wells which it dubbed "Frackibacter."
For further details see:
Rebecca A. Daly, Mikayla A. Borton, Michael J. Wilkins, David W. Hoyt, Duncan J. Kountz, Richard A. Wolfe, Susan A. Welch, Daniel N. Marcus, Ryan V. Trexler, Jean D. MacRae, Joseph A. Krzycki, David R. Cole, Paula J. Mouser, Kelly C. Wrighton. Microbial metabolisms in a 2.5-km-deep ecosystem created by hydraulic fracturing in shales.Nature Microbiology, 2016; 1 (10): 16146 DOI:10.1038/NMICROBIOL.2016.146
Posted by Dr. Tim Sandle