An ongoing federal investigation shows there were warning signs that natural gas was flowing into a well getting drilled in eastern Oklahoma near Quinton before it experienced a blowout that led to an explosion and fatal fire.
What investigators with the U.S. Chemical Safety and Hazard Investigation Board still hope to learn is how those signals were shared with and reacted to by the drilling crew, the on-site well operator and the drilling engineer at the Pryor Trust 0718 1H-9 on Jan. 22.
The most significant clue that natural gas was escaping into the well bore came as a crew operating the Patterson-UTI-owned drilling rig was testing a drill bit it had just replaced.
Data that investigators collected from the rig shows that during a period of in-hole testing lasting about 30 minutes, the rig’s mud pits gained 107 barrels of mud. Agency officials said that can signal that natural gas either had entered or had expanded inside the well bore, pushing the mud back to the surface.
They said the practice of monitoring fluid amounts held by drilling rig mud pits is widely followed within the industry, and that most monitoring systems are programmed to alert on-site personnel of fluctuations in those amounts ranging from five to 10 barrels.
Another sign there was about to be a problem, the investigation shows, is that a Patterson-UTI crew member observed mud flowing out of the well’s open blowout preventer at the same time the driller pulled the drilling bit back to the rig’s floor after completing its testing.
The blowout began one minute later, with an explosion and fire occurring soon thereafter, trapping five workers in the rig’s driller shack. Oklahomans Matthew Smith, Roger Cunningham and Parker Waldridge died in the mishap, as did Josh Ray of Fort Worth, Texas, and Cody Risk of Wellington, Colorado.
Autopsies showed they died of burns and smoke inhalation.
Investigations conducted by the U.S. Occupational Safety and Health Administration after the mishap cited Patterson-UTI drilling and two other companies, Crescent Consulting LLC, and Skyline Directional Drilling LLC, for exposing employees to fire and explosion hazards.
Specifically, OSHA cited Patterson-UTI and Crescent for failing to maintain proper controls while drilling a well, failing to inspect slow descent devices and failing to implement emergency response plans. Those cases remain open.
Skyline was cited along with the other two for failing to ensure that heat lamps in use at the time of the mishap were approved for hazardous locations. Skyline is contesting its violation before the Occupational Safety and Health Review Commission.
The three companies face penalties totaling $118,643, the maximum allowed for violation of the OSHA standards.
Also, numerous civil suits have been filed by victims’ relatives against the driller and the well owner and operator, Red Mountain Energy.
On Thursday, an attorney representing Ray’s widow and Risk’s children welcomed the update from the chemical safety agency, praising its ongoing investigation.
David L. Rumley, of Wigington Rumley Dunn & Blair, contends the well operator was at fault by using a lower-grade mud that wasn’t adequately weighted to control the well.
“It is clear that Red Mountain was more interested in trying to collect more money from investors than drilling the well safely,” Rumley stated in a release.
But Tony Say, president of Red Mountain Energy, responded to Rumley’s contention by stating, “Red Mountain denies it took any action to compromise safety at the Pryor Trust 1H-9.”
The planned vertical well was designed to reach a total depth of 7,615 feet and a total measured depth (including its lateral) of 17,799 feet. The well was targeting the Woodford Shale in the Arkoma Basin in Pittsburg County.
It had been drilled to a measured depth of 13,435 feet when a decision was made to pull the rig’s pipe string out of the hole so that the drilling bit could be replaced.
That process, called tripping, started at 6:48 p.m. the night before the explosion. The investigation notes the crew pumped 46 barrels of heavy mud into the well’s bore after midnight the morning of the explosion to prevent gas from flowing into the well’s bore as the operation continued.
By 6:10 a.m., the tripping operation had been completed. Just before 8 a.m., the driller lowered the new bit into the well’s bore for testing, pulling it back to the floor of the drilling rig at 8:35 a.m. The explosion happened at 8:36 a.m., the investigation shows.
It also states at least two people at the well location tried to close the blowout preventer (which is being tested as part of the investigation) after the mishap had started. The fire was extinguished about 4 p.m. the same day.
Kristen Kulinowski, the chemical safety agency’s interim executive, told reporters at Thursday’s news conference its investigation could last up to 18 months, noting it will attempt to identify lessons that could be learned to prevent future, similar incidents from happening. Unlike OSHA and state investigatory agencies, the agency doesn’t assign blame or issue fines as part of its work, she noted.
“This was a complex operation, and complex investigation, as a result,” Kulinowski said. “There were numerous entities that all worked together in some form or fashion to operate this well.
“So, part of our investigation is going to be looking at the interplay among those different entities, how they communicated with each other, what their procedures were and whether those were working effectively.”
A Patterson-UTI drilling rig burns at the well location near Quinton in eastern Oklahoma on Jan. 22. Five men were killed in the explosion and fire. [Photo provided by the U.S. Chemical Safety and Hazard Investigation Board]
This photo shows the Patterson-UTI rig at the Pryor Trust 0718 1H-9 after it had been consumed by an explosion and fire caused by a well blowout. [Photo provided by the U.S. Chemical Safety and Hazard Investigation Board]
(c)2018 The Oklahoman
Visit The Oklahoman at www.newsok.com
Distributed by Tribune Content Agency, LLC.