Are Steel Tubes Contributing to Tainted Water in Shale-Gas Areas?

Recent studies have emerged placing blame on steel tubes and bad cement for tainted drinking water in shale-gas areas.  Hydraulic fracturing was previously suggested to be the cause for water contamination in areas where natural gas is produced.  A new analysis published in The Proceedings of the National Academy of Sciences has confirmed what many have believed as of late.  The analysis proclaims, “there is no evidence that fractured shale led to water contamination” near several natural gas drill sites in Pennsylvania and Texas.   Fault lies with, for the time being, improperly built wells which lead to gas leaking up the wells into aquifers.

            The first step in the extraction of natural gas is carried out by gas producers who drill a deep vertical well which extends horizontally in several different directions.  Picture these expansion shafts as spokes protruding from a center hub.  A combination of steel pipe and cement are then used to line and seal the outside of the vertical wells.  What happens next is referred to as hydraulic fracturing or fracking.  Fracking involves injecting water and chemicals at high pressures into the “spokes”, creating fissures and releasing the natural gas trapped within the shale.  Why hydraulic fracturing was initially thought to cause gas to migrate into drinking water aquifers is a plausible explanation.  However, researchers concluded that fissures created by fracking are not long enough to affect aquifers. 

Thus, attention was focused on the next possible cause, gas leaking out of the steel lined and cement sealed vertical well.  Unfortunately, well integrity is a widespread problem in the oil and gas industry.  Scott Anderson, who deals with energy production issues for the Environmental Defense Fund, revealed that “15% of all cement sealing of wells may be imperfect”.  Mr. Anderson believes that improvements in well integrity could eliminate environmental problems caused by gas leaks.  He even offers suggestions that gas producers could us in taking steps towards eliminating leaks.  For example, ensure the proper cement and steel tubing is used as well as monitor pressures during well construction and while gas is flowing. 

Could imperfect wells be related to smaller companies with a lack of drilling experience in some shale-gas areas?  There are statistics that show a correlation between larger companies drilling better wells.  Although, according to Scott Anderson, this may not necessarily be true.  “Some of the best wells, from a technical standpoint, are drilled by the smallest operations.”

Now that the cause of the issue at hand has been determined, will the government implement changes to the process of natural gas production?  What steps will gas companies implement in order to prevent leaks from occurring in the future?  Hopefully imperfect wells are not the result of pure negligence by gas companies and there really are improvements that can be made towards improving well integrity.