Talisman Energy Inc. temporarily shut down all hydraulic fracturing (fracking) operations in North America while it investigated a well control incident that occurred Jan. 17 at a Talisman natural gas well on state forest land in Tioga County, PA, the Pennsylvania Department of Environmental Protection (DEP) said Tuesday. DEP is conducting a separate investigation of the incident.

Talisman’s “voluntary fracking stand down” has ended and the company is “continuing full operations right now,” a company spokesman told NGI’s Shale Daily Tuesday afternoon.

Fracking fluids and sand “discharged from the well into the air” during the incident, according to DEP, which said “it does not appear that any significant amount of natural gas was released and there was no fire or explosion.”

Talisman said it discovered “a water-based fluid release” at a well it operates in Tioga County at 12:10 p.m. Jan. 17. DEP Oil and Gas and Emergency Response program staff responded to the scene and Talisman contacted CUDD Well Control to assist with gaining control of the well, which was successfully shut in about 3:35 p.m. that day.

“Our investigation is ongoing and we are providing information to the DEP,” Talisman said. “Our preliminary findings indicate the cause of the incident was due to a mechanical issue on the well site. As a result, we have modified our component design to prevent this from reoccurring.”

Inspections conducted by DEP staff have verified that the fluids were contained to the lined well pad. The fluids were cleaned up by a contractor and further sampling will be conducted to determine if any contaminated soil needs to be removed, DEP said. Soil samples from beneath the well pad liner were collected by Oil and Gas Program staff.

“This was a serious incident that could have caused significant environmental harm had it not been brought under control,” said DEP North-central Regional Director Nels Taber. “DEP is conducting a thorough investigation to determine why this incident occurred.”

Talisman “has been cooperating fully with the department,” and voluntarily shut down its fracking operations while investigating the cause of the incident, DEP said.

DEP sent a notice of violation letter Monday that requires Talisman to submit a sampling plan for the site, information on any fluids released, an analysis of the main cause of the incident and changes to be implemented in all of its Marcellus operations as a result of the incident.

Last year DEP fined EOG Resources and a contractor after they lost control of a well while performing post-fracturing well cleanout activities (see Daily GPI, July 14, 2010). That blowout in Clearfield County, PA, was caused primarily by untrained personnel and a failure to use proper well control procedures, according to DEP. EOG was fined $353,400 and C.C. Forbes $46,600, and both were ordered to take corrective actions to avoid a repeat of the incident.