The gas drilling industry has for decades claimed that hydraulic fracturing (fracking) has never caused water pollution. But The Wall Street Journal reports that some industry officials, government investigators, and environmental critics are now pointing to poorly cemented wells as the primary cause of aquifer water pollution in high-drilling regions of the U.S.. They point out that the wells involved were improperly sealed with cement that allowed contaminants to migrate up the well bores and contaminate aquifers. However, some anti-drilling activists claim that it is the fracking that is causing the water pollution. The drilling industry and some environmental groups are calling for much stronger cementing standards as a cure for as high as 1 in 10 well failures (according to the Environmental Defense Fund). Federal investigators say that a major cause of the Deepwater Horizon well blowout in 2010 was caused by improper cementing of the well.
Cementing is an essential procedure in natural gas drilling procedures, in which steel pipes are threaded into deep bore holes and cement is forced around the pipe, ideally preventing the frack gas, waste water, or natural or man-made chemicals from moving between the case and exposed rock. A poorly cemented well can create a path for contaminants to migrate upward and leech into shallow porous rock aquifers that hold drinking water. A U.S. Energy Department committee in a report last August called for drill companies to run tests on every well to identify inadequate cementing. It also called for more inspections to confirm that operators have promptly repaired defective cementing jobs.
An invesitgation last by the Pennsylvania DEP of the Bradford drinking-water contamination near a drill site concluded that the driller, Chesapeake Energy Company, failed to cement its wells adequately, causing gas to leak from the pipes and contaminate groundwater. The company paid $900,000 in fines and said it plans to use three interlocking pipes in its drilling rather than the standard two.