Tight shale oil and gas producers need to address public concerns more effectively as technological processes help them improve recovery rates and reduce surface disruptions, a speaker told the US Energy Association’s 2016 Energy Supply Forum on Oct. 6.
Of the 10,000 unconventional wells that have been drilled in Pennsylvania, only 32 have had methane migration problems, said hydrogeologist Dave Yoxtheimer, an extension associate at Penn State University’s Marcellus Center for Outreach & Research who also helps advise stakeholders on environmental issues.
“That’s about 99.7% of the wells which haven’t had to deal with methane migration,” Yoxtheimer said. “The real risk is spills at the surface. Better fluids management and secondary containment are part of the answer. But if there are any problems at all, more work needs to done. Pennsylvania’s producers and regulators are doing just that.”
Unconventional wells represent about half of the nation’s total oil and gas production, Yoxtheimer said. Newer ones are much more efficient than their predecessors in several ways, he stated. They take 2 weeks to drill compared with 5-6 weeks. More rigs run on natural gas, which can save up to $1 million/year in drilling costs per rig. Shorter intervals are being hydraulically fractured. Larger laterals also are reducing production costs.
“Obviously, there are seismicity issues in some parts of the country, which means we need to be careful about how we manage fluids disposals,” Yoxtheimer said. “Recycling fluids is ideal, but there are cases where they have to be treated. Sometimes, this can be so effective that the fluids can be released into streams. Other times, they need to be reinjected properly into the formations they came from.”
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