The Pennsylvania Department of Environmental Protection (DEP) has given Cabot Oil & Gas Corp. permission to resume drilling at a Marcellus Shale natural gas well pad in Susquehanna County after an investigation found no elevated levels of methane in private drinking water wells.
The DEP and Houston-based Cabot launched an investigation in Lenox Township on Aug. 16 after three private drinking water wells appeared to be impacted by possible methane gas migration and combustible gas was found bubbling from a local pond (see Shale Daily, Aug. 29).
DEP spokeswoman Jamie Legenos told NGI's Shale Daily on Thursday that Cabot was given permission to resume drilling at the Zick well pad "based on the results of the company's survey of nearby homes and drinking water wells that did not document elevated levels of methane." She added that the bubbling at the pond had also ceased.
Cabot spokesman George Stark told NGI's Shale Daily that drilling resumed Aug. 29 at the Zick well pad. The company was in the process of drilling the last of five horizontal wells there when the investigation began.
"We are pleased that the results came back as such around the Zick," Stark said Thursday. "We did a thorough review of the water wells within 2,500 feet of the Zick pad and either found no detection of methane or an amount that was equal to or less than the pre-drill. We did not visually observe any bubbling at the pond and testing did not detect any methane. The DEP had their own likewise data."
Legenos said the DEP's Oil and Gas Program would continue to monitor the area, and the DEP would evaluate isotopic sample results from gas samples collected in the area. She said test results would not be expected for a couple of weeks.
"At this time the department has not made a final determination with regard to what impacts, if any, Cabot's earlier drilling may have had in the area," Legenos said.
Stark said Cabot was still working with the DEP to determine the source of methane that impacted three private drinking water wells near a second well pad, the Stalter. Stark said that pad has three wells -- one vertical and two horizontal -- and only one has been hydraulically fractured.
"When we get a call for an elevated [methane] reading, we want to respond quickly," Stark said, adding that the company has vented the three impacted private drinking water wells, installed methane alarms in each of the three affected homes and is providing drinking water to one of the residents. "We are continuing to work with the DEP around the Stalter. No other areas around the Stalter have had elevated methane readings."
In a settlement with the DEP last December, Cabot agreed to pay $4.1 million after residents in Dimock Township, also in Susquehanna County, had their drinking water supplies contaminated by natural gas (see Shale Daily, Dec. 17, 2010). The company agreed to pay to install whole-house gas mitigation systems for each of the 19 homes affected and to pay the state $500,000 for its two-year investigation into the incident.