Chesapeake Energy Corp. has agreed to allow the Environmental Protection Agency (EPA) conduct extensive tests at one of its drilling sites as part of the federal agency’s ongoing investigation into the safety of hydraulic fracturing (fracking). Range Resources Corp. also may allow EPA to work at one of its drilling sites.

The Chesapeake tests, which would involve water sampling at an undisclosed drilling site before and after the project is conducted, would serve as a cornerstone of EPA’s study to determine whether fracking poses a risk to water supplies. EPA issued an interim update on the study in late December; a draft report is expected in 2014 (see Shale Daily, Dec. 24, 2012).

Last month EPA said it had begun five case studies in the Marcellus, Barnett and Bakken shale, as well as the Raton Basin, on the impact of fracking on drinking water sources (see Shale Daily, Dec. 31, 2012). Five retrospective case studies were planned to investigate reported drinking water resource contamination reports where fracking had occurred.

Prospective case studies — with industry partners — also were announced last month at sites where fracking would be used after research begins to allow EPA to sample and characterize the site before, during and after drilling, fluid injection, flowback and gas production.

Chesapeake, the second largest U.S. gas producer after ExxonMobil Corp., and EPA are said to be “very close” to choosing a location and a start date.

Range may participate as well, but an agreement with EPA has been delayed by researcher liability concerns, a spokesman said.

The retrospective studies may include drilling projects by Pioneer Natural Resources Co., Denbury Resources Inc. and Cabot Oil & Gas Corp. (see Shale Daily, March 19, 2012). EPA still is working on a study of gas drilling in Pavillion, WY, after Encana Corp. and state agencies challenged a draft report that suggested a drilling link to water contamination in the area (see Shale Daily, Jan. 14).

However, some of the most important work would be based on before-and-after water testing, and Chesapeake’s participation gives the agency access to an active drilling project.

Chesapeake CEO Aubrey McClendon and other gas executives long have said water testing at drill sites would prove natural gas drilling doesn’t contaminate water supplies.

“The value of these tests is that they are really the first independent review of what’s happening from start to finish,” said Natural Resources Defense Council scientist Briana Mordick.