Recently released data on drilling violations from the PA Department of Environmental Protection show that problems continue with the cemented steel casings that are designed to protect groundwater from methane and the fluids used to frack wells. The violations do not mean methane or fluids escaped into local groundwater aquifers—but the potential exists when a well is not cased properly. So far in 2011, 65 wells have been cited for faulty casing and cementing. Out of the many thousands of wells drilled and fracked each year in Pennsylvania, that’s not a bad ratio, but it’s certainly nowhere near acceptable. As DEP Secretary Michael Krancer has said, “One case of methane migration or well contamination is one case too many.” The industry needs to do better.
In August, DEP inspectors found defective or inadequate casing or cement at eight Marcellus wells, including Hess Corp.’s Davidson well in Scott Twp., Wayne County – the first casing violation found in the county where only a handful of Marcellus wells have been drilled.
During the first eight months of 2011, 65 Marcellus wells were cited for faulty casing and cementing practices – one more than was recorded in all of 2010.
Casing and cementing violations do not necessarily indicate that gas has or will migrate into drinking water supplies, and methane is present in many water wells in Pennsylvania from natural pathways unrelated to gas drilling. But in the three dozen instances when methane has migrated into water supplies from gas wells in Northeast Pennsylvania, cement flaws have been identified by state regulators as a primary pathway for the gas.
The increase in casing and cementing violations reflects the state’s increased attention to the issue, especially since the regulations were updated in February. The steady pace of new violations – an average of eight new wells a month have been cited for casing, cement or leaking gas violations this year – also indicates the complexity of the problem in a state where the geology is neither uniform nor predictable.
Most of the casing and cement violations recorded this summer became evident to inspectors when bubbles rose from between the cemented casing strings in water pooled at the well sites or when combustible gas was detected with meters at the surface, according to notes in the violation reports posted by the department online.
The department considers bubbling or escaping gas at the surface an indication of problems below.
In June, July and August, bubbling or escaping gas was noted during inspections of Marcellus wells in Wayne, Wyoming, Susquehanna, Bradford and Lycoming counties in the northeast and northcentral region. The wells’ operators include Chesapeake, Hess, Exco Resources, Williams Production and XTO Energy.*
*Towanda The Daily Review (Sep 18, 2011) – DEP inspections show more shale well cement problems