We’ve often talked on this blog about the lessons to be learned from safety alerts, and why it’s so helpful to share them. That’s why we’ve decided to feature a few of them here. In this Safety alert! series we’ll be examining some injury incidents and some near misses, to see what we can take away for next time.
This week we start the series with a look at a hazardous gas release on a snubbing operation.
A snubbing crew was working on a producer location in Northern Alberta, and at the time of the incident they were installing the snubbing unit equalizer line and the pumping unit flow line.
The casing valve was assumed to be closed, but in fact it wasn’t properly sealed, due to a build-up of ice. When the operator discovered the ice he sprayed methanol on it, and then tried to break it up with a steel chisel. The snubbing supervisor arrived on the scene just as the ice plug was finally removed, at which time a high pressure flow of wellbore gas and fluid was released. The crew evacuated.
It wasn’t until they met at the safety meeting point that they noticed the supervisor was missing. He was unconscious at the wellhead. The crew went in to retrieve him, and then fully closed the valve.
Why getting the job done shouldn’t always be priority #1
Like all safety alerts, we’ll start by taking a look at what went wrong:
- Cold temperatures caused ice to plug the production casing valve.
- The production casing valve appeared to be fully closed, but no-one confirmed that the correct number of turns had been achieved to fully close it.
- When the ice plug was discovered, the ‘out-of-scope condition’ wasn’t reported to a supervisor.
- The job wasn’t stopped when the ice plug was discovered, and no hazard assessment was conducted.
- Proper tools weren’t used to removed the ice plug.
It’s easy to see that it wasn’t one single mistake that caused the problem. Like so many incidents it was a combination of small safety lapses, culminating in a crisis.
What we learned
The biggest lesson here is that safety processes are there for a reason! Specifically, these are the actions that would have helped prevent this incident:
- Hazard assessment. The potential for ice plugs or other build-up in piping systems should have been explored, as well as the associated trapped pressure hazards.
- Know your equipment. When closing gate-style valves, know the number of turns to open/close, and make sure that number is achieved.
- Look for hidden dangers. Workers should have assumed that a plug within a piping system could contain trapped pressure.
- Stop the job! When out-of-scope conditions are met, stop the job and report to a supervisor.
- Re-assess hazards. When out-of-scope conditions are met, always complete a new, specific hazard assessment to determine the safe course of action.
You can read the full safety alert in ‘Snubbing Operations Gas Release’.
This crew learned some valuable lessons that day, including the importance of process safety and hazard assessments. They also learned that it’s better to stop the job and cause a delay than risk a potentially fatal incident. The common belief that ‘everything will work out fine’ doesn’t always cut it when it comes to safety.
Incidents like these are avoidable, and helping spread the lessons learned is part of the reason we publish safety alerts. It’s also the reason we place such an emphasis on the operationalization of safety culture. Because when safe behaviours become automatic and natural, that’s when safety happens.
Stay tuned as we share more safety alerts in future posts.