Source: http://thetimes-tribune.com, July 30, 2014
By: Brendan Gibbons
Five natural gas wells in Bradford County have leaked methane for years because of persistent casing and cement problems, according to state Department of Environmental Protection records.
In May, a DEP inspector found combustible gas flowing through vents connected to the cement between layers of pipe. The department issued a notice of violation for each well in June, saying combustible gas outside the well’s surface casing violates state regulations.
Houston-based EOG Resources Inc. began drilling the wells in Ridgebury and Springfield townships in late 2010 and early 2011. None of them have reported any production.
The wells were not tests and were eventually intended for production, DEP spokesman Dan Spadoni said. An EOG spokeswoman would not answer any questions about the wells.
For four of the wells — Rightmire 2H, Melchionne 1H, Wenger 1H and Miccio 1H — EOG reported its violations to the DEP after its safety inspector measured gas venting from the wells’ annuli in 2011. The company blamed “defective, insufficient or improperly cemented casing.”
The DEP also inspected the Oberkamper 1H well on May 22 after a July 2013 inspection found EOG piped the vents in a way that prevented accurate measurement. The inspector found methane outside the surface casing
The annulus is the space between layers of pipe. Operators fill these layers with cement in part to prevent gas and other fluids from migrating outside the wells.
Each well has four layers of steel pipe. EOG’s inspector found gas flowing from two to three annuli per well, ranging from 709.5 to 1,134 cubic feet per day, cumulatively.
Nothing prevents this methane from flowing into the atmosphere, where it acts as a greenhouse gas. Methane has a global warming potential 21 times more potent than carbon dioxide, according to the U.S. Environmental Protection Agency.
The DEP is not aware of any drinking water contamination from these wells, Mr. Spadoni said.
In March 2012, the company submitted a plan to fix some gas flow from three of the wells “by applying pressure to a pressure-activated sealant.” The company also committed to pumping cement across the Upper Devonian Sands, a rock layer above the Marcellus Shale. This was the only solution EOG proposed for the Wenger well.
The cementing would occur “upon completion of the producing life of the well,” according to EOG’s plan. The time frame varies per well but could mean up to 30 years, according to a recent Penn State University analysis of gas wells across the state.
The DEP did not approve of the EOG’s fix for two of the wells, records state, but EOG went ahead with its plans.
“Although the strategy was not approved by the Department, the surface casing annulus was sealed at the surface in 2012,” the notices of violation for the Melchionne and Miccio wells state.
In June 2013, a DEP inspector returned and found gas flowing from pipes that vented the wells’ annuli. This gas was at 5 percent concentration, the lower explosive limit, in at least one annulus for all four wells. In July 2013, an inspection of the Oberkamper 1H well revealed the vent was piped in a way that prevented accurate measurements.
The DEP did another round of inspections May 22. It found combustible gas outside the surface casing for all five wells. The DEP did not assess any fines, Mr. Spadoni said.
The violation notices required a response within 30 days of receipt. Mr. Spadoni said EOG has not finished addressing any of the wells, but he would not say how the company plans to fix them.
“We are still working through this issue with EOG and are not in a position to summarize their response,” he said in an email.