Aug. 16–Chemical safety board officials said massive mud gains were a “strong indication” of gas influx leading to the Patterson 219 rig explosion this year.
During a Thursday news conference, U.S. Chemical Safety Board officials released investigation details regarding the Jan. 22, 2018 explosion at the Patterson 219 rig in Quinton that left five men dead.
“Based on our investigation to date, we can confirm today that the blowout occurred shortly following the removal of drill pipe from the wellbore — an operation called ‘tripping,'” CSB Interim Executive Dr. Kristen Kulinowski said.
But she said the investigation is “far from over” as the board targets completing each of its investigations within 12-18 months of the incident date.
Red Mountain Energy, LLC, was the lease holder, and Red Mountain Operating, LLC, was the operator of the well. RMO hired Patterson-UTI Drilling Company, LLC, as the drilling contractor and the Patterson Rig 219 drilled the well. Well 1H-9 was a lateral well planned to reach a true vertical depth of 7,615 feet and measured depth of 17,799 feet.
According to the CSB, there were two Patterson drilling crews for Rig 219 working two different shifts on each hitch — a 14-day working period. Each crew included a driller, a derrick hand, a motor man and floor hands, with one working 6 a.m. to 6 p.m. and the other working from 6 p.m. to 6 a.m. Onerig manager worked parts of each shift and the “two crews had been on-hitch” since Jan. 10.
The report states there were two company men working each hitch that were contracted by RMO, which also contracted the drilling engineer.
Crews stopped drilling Jan. 21 to “remove the drill pipe from the well bore to change the drill bit,” aka tripping out, according to the report.
During the tripping out process, Patterson crew members turned on the mud pumps at 8:09 a.m. — however, the mud pits had gained 107 barrels of mud between 7:57 a.m. and 8:35 a.m.
CSB lead investigator Lauren Grim said this is an indication of gas influx and most companies have systems in place to alarm employees of the potential hazard.
She said companies generally set alarm systems for gains of 5-10 barrels.
“The gain is a strong indication of potential gas influx into the well bore for the crew members,” Grim said. “Oftentimes, when a gain like that is seen, general guidance suggests you stop operations.”
A Patterson drilling crew member witnessed mud flowing out of the open blowout preventer stack at 8:35 a.m., according to the report.
CSB officials said rig data indicates “conditions existed that could have allowed a gas influx into the wellbore beginning during the tripping operation,” and will be explained in the final report.
One minute later, mud blew up out of the well as “the motor man and a floor hand, who were on the rig floor, entered the driller’s shack” and the gas and oil-based mud ignited, causing the fire on the rig.
Grim said the board is still investigating several potential ignition sources and communication procedures at the site.
Two workers tried to close the blowout preventer, but the blind rams did not fully close, the report states.
CSB officials said the BOP stack is located under the rig floor and investigators are looking into the equipment’s maintenance history.
A well control services company and RMO personnel manually closed the BOP blind rams and stopped the fire at 4 p.m.
Five workers died in the event, including Matt Smith, 29, of McAlester, Oklahoma; Josh Ray, 35, of Fort Worth, Texas; Cody Risk, 26, of Wellington, Colorado; Parker Waldridge, 60, of Crescent, Oklahoma; and Roger Cunningham, 55, of Seminole, Oklahoma.
The CSB report states the five “were in the driller’s shack or ran into the driller’s shack during the blowout and fire” and included an RMO employee, a Skyline Directional Drilling directional driller, a Patterson driller, a Patterson floor hand, and a Patterson motor man.
Attorneys have filed lawsuits on behalf of the families or estates of the five workers and District 18 District Judge James Bland granted a motion on May 9 to consolidate the five lawsuits for discovery and pretrial litigation.
Patterson 219 began drilling well 1H-9 on Jan. 11 and reached a measured depth of 13,435 feet — a true vertical depth of 7,643 feet — by Jan. 21, the report states.
The Patterson drilling crew stopped drilling at 3:36 p.m. on Jan. 21 “so that they could remove the drill pipe from the well bore to change the drill bit” — aka tripping. Crew members began tripping the well at 6:48 p.m.
Patterson crew members performed a calculated fill, aka a force fill or volumetric fill, a method involving closing an isolation vale in the mud return flow line, or the orbit valve.
The report states this method was decided upon by the drilling engineer and the two company men before being consented to by the Patterson drilling crew and RMO.
Patterson-UTI Drilling, Crescent Consulting LLC, and Skyline Directional Drilling LLC were cited by the federal Occupational Safety and Health Administration for allegedly “exposing employees to fire and explosion hazards” in the Jan. 22 incident that left five men dead.
All three companies were cited for failing to ensure that heat lamps in use were approved for hazardous locations, according to OSHA documents. OSHA also cited Patterson-UTI and Crescent Consulting for “failing to maintain proper controls while drilling a well, inspect slow descent devices, and implement emergency response plans.”
CSB officials said the board’s investigation is independent of OSHA.
The CSB report states the Patterson crew at 12:35 a.m. on Jan. 22 pumped a 46-barrel, 10-pound-per-gallon weighted pill intended to prevent gas influx into the well.
Crew members continued tripping drill pipe with the continuous fill method at 1:12 a.m. and the orbit valve was open for this operation, the report states. The CSB noted that the drill pipe being removed near the beginning of the operation had not drained and contained mud. The crew tried to pump a weighted slug into the drill pipe to push out the mud, but was unable to pump the slug into the drill pipe because the drill pipe was plugged, according to CSB.
“The crew therefore had to trip drill pipe the rest of the way out of the wellbore with the removed piping sections containing mud,” the report states.
According to the report, the next shift of Patterson crew members finished removing the drill string and bottom hole assembly and the driller closed the blowout preventer blind rams at 6:10 a.m.
The driller opened the blowout preventer blind rams at 7:58 a.m. and the driller lowered a new bottom hole assembly into the wellbore one minute later, the report states.
CSB reported the explosion occurred at 8:36 a.m.
Kulinowski said the next step in the ongoing investigation is to determine the causes of the blowout. She added the investigators continue analyzing rig data from days leading up to the incident, interviewing personnel, and assessing documentation.
Details and recommendations will be provided in the CSB’s final report.
Contact Adrian O’Hanlon III at email@example.com
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