Wednesday, September 12, 2012

Water pollution from oil and gas drilling can be expected in karst regions, federal expert says

More and more drilling applications have been filed during the natural-gas boom for karst regions, with "a type of geology made of rocks that dissolve in mildly acidic water over time," and and oil and gas wells do fail over time in karst regions, which provide easy geologic pathways for pollution, says James Goodbar, head of the Bureau of Land Management's caves and karst resources program, reports Gayathri Valdyanathan of Energy and Environment News.

Scientists worry that contamination will increase if drilling increases in these regions. If drilling is properly done, with the correct amount of steel and cement casings, not much casing is needed in most geologic structures. But when well bores intersect with caves, drilling can pose greater risks. The cement and metal can corrode and leak over time because it's not surrounded by rock. "Threats to the springs and the wildlife that depend on them may be significant," Valdyanathan reports.

The BLM updated requirements for karst drilling in 2006, requiring at least three layers of high-grade steel and cementing, and plugging from the lowest karst zone when abandoning a well. But those standards aren't applicable on non-federal karst lands, or on older wells. (Read more)

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