From EurekAlert! Science News:
Researchers have found that the microbes inhabiting a hydraulically fractured shale formation produce toxic, corrosive sulfide through a poorly understood pathway. The team's findings, published this week in mSphere®, an open-access journal of the American Society for Microbiology, reveal that the oil and gas industry may need new ways to monitor and mitigate sulfide-producing bacteria in fractured shales.
"This is a pretty inhospitable environment of high pressure, salinity and temperature some 2,000 meters underground. You'd think that microbes introduced during the fracturing process would die, but some of them make a good life for themselves," says Mike Wilkins, an environmental microbiologist at The Ohio State University in Columbus and senior researcher on the study. "The industry spends a fair amount of money trying to keep microbes out of these systems."
Hydraulic fracturing, also known as "fracking," involves the high-pressure injection of water, sand, and chemicals into shale formations to create fracture networks that release oil and gas, which are pumped back to the surface and recovered. Practiced for only the last decade, not much is known about the microbial ecosystems in the fracture networks.
Sulfide-producing microbes cause multiple problems for drilling operations. Hydrogen sulfide can "sour" a well and must be separated from oil and gas in an expensive process. Sulfides can be toxic to the workers on the drilling pad and can also corrosively degrade metal pipelines. The microbes themselves can gum up the extraction process by filling in the tiny fractures with either biomass or excreted precipitates.Read more by clicking here.
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