A 2018 drilling rig fire in Oklahoma killed five people and destroyed the rig. - Screencapture Via YouTube

A 2018 drilling rig fire in Oklahoma killed five people and destroyed the rig.

Screencapture Via YouTube

Two families will split a $20 million award in a wrongful death lawsuit stemming from a January 2018 oil rig fire in Oklahoma that the U.S. Chemical Safety Board called the deadliest drilling accident since the 2010 Deepwater Horizon rig explosion.

The families of Josh Ray of Fort Worth, Texas, and Cody Risk of Wellington, Colorado, two of the five people killed in the fire, sued Red Mountain Energy, Crescent Consulting, Patterson UTI and National Oilwell Varco as responsible for the January 21, 2018 accident near Quinton, Oklahoma.

“Failure to accept any responsibility for the explosion meant a jury verdict was required for these families, and justice was served,” trial attorney Jeff Wigington said.

The CSB determined the incident occurred shortly after drilling crew members removed the drill pipe from the well in a process known as “tripping.” The report established the following timeline related to the blowout and fire:

Jan. 21, 2018: Crew members from the Patterson-UTI Drilling Company had been drilling a gas well for over a week. Activities were being overseen by the operator of the well, Red Mountain Operating, LLC (or RMO) in Pittsburg County, Oklahoma. 

At 3:36 pm, the Patterson crew stopped drilling to remove the drill pipe from the well and change the drill bit.  

At 6:48 pm, crew members began the process of removing the drill pipe from the well. The Patterson crew pumped mud into the well during the removal of the drill pipe with the intent to keep the well full of mud. That operation involved closing an isolation valve to prevent mud from flowing out of the well.  By 10:30 pm, the end of the drill pipe reached the top of the curve in the well.

Jan. 22, 2018: At 12:35 am, the crew pumped fluid also referred to as a “weighted pill” above the top of the curve to prevent gas influx into the lateral portion of the well. 

At 1:12 am, the crew began removing the drill pipe from the vertical section of the well. For this portion of the operation, the Patterson crew performed a “Continuous Fill” tripping method. Mud was continuously circulated in the wellbore using the Trip Tank pumps to keep the well full by replacing the volume of the drill pipe removed with drilling mud. The isolation valve was open for this operation.

At the start of this procedure, the drill pipe started pulling 'wet' —  meaning the drill pipe being removed had not drained and still contained mud. The Patterson crew was aware that the pipe was plugged. At this point the Patterson crew attempted to pump a volume of mud also referred as a "slug" into the drill pipe to push the mud that remined in the drill pipe out, but this was not successful as the drill pipe was plugged. Therefore, the drill pipe in the vertical section was removed while it still contained mud. 

By 6:10 am, the drill pipe and drill bit were completely removed from the well. At that time, the driller closed the blind rams on the well’s blowout preventer.

At 7:57 am, the driller opened the blowout preventer blind rams so that a new piece of drilling equipment called a bottom hole assembly could be lowered into the well. At 8:09 am, mud was pumped through the bottom hole assembly to test the new equipment.

While the rig crew tested the bottom hole assembly equipment, the mud pits gained 107 barrels of mud. Mud pit gains are an indication of a possible gas influx in the well. Data obtained by the CSB indicates that conditions existed that could have allowed a gas influx into the wellbore during the tripping operation. 

At 8:35 am, with testing complete, the bottom hole assembly was lifted out of the wellbore. At 8:36 am, mud blew upwards out of the well. The mud and gas from the well subsequently ignited causing a large fire.

The final report issued by CSB in June 2019 blamed the accident on poor barrier management; operations performed without proper planning, procedures or needed equipment; signs of influx either not identified or inadequately responded to; an alarm system turned off and flow checks not conducted.

Twenty-two workers were at the well site at the time of the blast. The fatalities, ranging in age from 26 to 60, made their homes in Oklahoma, Texas and Colorado.