CNX Resources Corp. continues to investigate how it lost control of a deep, dry Utica Shale well in southwest Pennsylvania late last month, but the company revealed in a regulatory filing that it faulty casing could be to blame.
The company experienced a “pressure anomaly” during hydraulic fracturing operations on Jan. 25 that forced it to stop all operations at the Shaw pad in Westmoreland County. Pressure in nearby shallow conventional wells spiked, requiring CNX to flare gas from them. A well control team successfully killed the well on Feb. 5 and stopped the subsurface flow of gas.
In its annual report filed with the U.S. Securities and Exchange Commission last week, CNX said while it continues to evaluate the cause of the incident, “it appears that the pressure anomalies that the company observed were caused by a casing integrity issue at a depth below approximately 5,200 feet.” The issue allowed gas to travel up the Shaw 1G wellbore and escape into shallower formations, it said. “CNX believes this issue is isolated to this well.”
The company had been flaring nine nearby wells, but spokesman Brian Aiello said just four were still being flared on Monday.
In all, there are four deep, dry Utica wells on the pad that were drilled last year. They’re all shut-in as the investigation continues. Two of the wells are drilled but uncompleted, but another well was also being stimulated at the time of the pressure anomaly on the Shaw 1G, Aiello said.
CNX said in its filing personnel would continue to monitor the Shaw 1G and the shallow oil and gas wells nearby. Aiello added that those efforts would continue around the clock until further notice. The Shaw 1G reaches a depth of more than 13,000 feet and has a lateral of roughly 8,000 feet. There are dozens of deeper unconventional wells in the area, but none were affected by the incident.
CNX in 2014 drilled its first Pennsylvania Utica well in Westmoreland County. The formation is deeper and more pressurized in the state than it is across the border in Ohio. Just to the south of the Shaw pad is CNX’s Bell Point 6 deep Utica well, which has been producing steadily at 21 MMcf/d since October, management recently said during the company’s year-end earnings call.
The Shaw pad in Washington Township is near the Beaver Run Reservoir, which provides drinking water to more than 100,000 people. The well issues caused no injuries or environmental impacts, but the company said in its filing that it continues to work with the local water authority and state regulators as the investigation continues.
The state Department of Environmental Protection has requested a root-cause analysis along with other data and information about the incident, but it’s not clear when the agency might receive all of that, said spokesperson Lauren Fraley.