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What happened?
Contractor A finalised maintenance on the valves of a well production tree and left the well closed.
Contractor B performed a pneumatic test on the well testing lines, which failed due to flaws in the packing of the hammer unions.
System was depressurised through the desander (BBS) bleed orifice as there weren’t enough parts available to fix all the flawed unions.
Production engineering decided to open the well through the contingency line during the night while Contractor B finished repairing the flawed hammer unions.
Two workers in the day shift continued the repairs and decided to check the filter inside one of the de-sander’s spheres.
They checked for pressure build-up – verifying the position of the valves that isolated the filter and checking for noise when opening a needle valve.
When unscrewing the sphere's cap with a J wrench, a sudden pressure release occurred, forcing the cap into the air.
The cap fell 7m(23ft) away from the de-sander. Luckily, no workers were injured.
The pressure build-up was calculated to be 850psi.
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Why did it happen?
The valves used to isolate the desander were defective – allowing pressure build-up within the equipment.
No pressure gauges were installed on the filter spheres to allow for pressure verification.
Cap thread was too tight, which workers did not identify.
Handover was not performed during the shift turn.
No hazard analysis or pre-job meeting was conducted, even though applicable procedures requested so.
Verification of the desander's filters was not part of the planned work scope.
Investigation report revealed that the desander filter cleaning operation was not carried out in the recommended sequence.
The two workers in the day shift were inexperienced, with no training record for the relevant procedures (hazard identification, LOTO, and de-sander cleaning).
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What did they learn?
Pre-job safety talks are crucial for all workers to understand the scope of work.
If the scope changes, stop the work and reassess the hazards.
Ensure shift-change procedures are in place and adhered to.
All workers should be trained and competent for the tasks.
- Review and develop a training plan for new and existing employees.
- Consider incorporating trainers/experienced personnel in high pressure gas operations in field crews.
Review and update applicable procedures for lockout tagout (LOTO) and desander cleaning (where applicable). Communicate to all personnel.
Write a procedure for shift changes and specify formats to register pre-job meetings.
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Ask yourself or your crew
What are the steps in our LOTO procedure?
What is the recommended sequence for (desander) filter cleaning operations?
What should you do if an additional task comes up while you are performing your planned task?
What do you have to do when changing shifts (handover, paperwork, etc.)?
How can we improve communication between the teams working on our site?
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What happened?
Contractor A finalised maintenance on the valves of a well production tree and left the well closed.
Contractor B performed a pneumatic test on the well testing lines, which failed due to flaws in the packing of the hammer unions.
System was depressurised through the desander (BBS) bleed orifice as there weren’t enough parts available to fix all the flawed unions.
Production engineering decided to open the well through the contingency line during the night while Contractor B finished repairing the flawed hammer unions.
Two workers in the day shift continued the repairs and decided to check the filter inside one of the de-sander’s spheres.
They checked for pressure build-up – verifying the position of the valves that isolated the filter and checking for noise when opening a needle valve.
When unscrewing the sphere's cap with a J wrench, a sudden pressure release occurred, forcing the cap into the air.
The cap fell 7m(23ft) away from the de-sander. Luckily, no workers were injured.
The pressure build-up was calculated to be 850psi.
Why did it happen?
The valves used to isolate the desander were defective – allowing pressure build-up within the equipment.
No pressure gauges were installed on the filter spheres to allow for pressure verification.
Cap thread was too tight, which workers did not identify.
Handover was not performed during the shift turn.
No hazard analysis or pre-job meeting was conducted, even though applicable procedures requested so.
Verification of the desander's filters was not part of the planned work scope.
Investigation report revealed that the desander filter cleaning operation was not carried out in the recommended sequence.
The two workers in the day shift were inexperienced, with no training record for the relevant procedures (hazard identification, LOTO, and de-sander cleaning).
What did they learn?
Pre-job safety talks are crucial for all workers to understand the scope of work.
If the scope changes, stop the work and reassess the hazards.
Ensure shift-change procedures are in place and adhered to.
All workers should be trained and competent for the tasks.
- Review and develop a training plan for new and existing employees.
- Consider incorporating trainers/experienced personnel in high pressure gas operations in field crews.
Review and update applicable procedures for lockout tagout (LOTO) and desander cleaning (where applicable). Communicate to all personnel.
Write a procedure for shift changes and specify formats to register pre-job meetings.
Ask yourself or your crew
What are the steps in our LOTO procedure?
What is the recommended sequence for (desander) filter cleaning operations?
What should you do if an additional task comes up while you are performing your planned task?
What do you have to do when changing shifts (handover, paperwork, etc.)?
How can we improve communication between the teams working on our site?
Repair work was being carried out on hammer unions in a well. Workers were checking the desander sphere when pressure forced the sphere’s cap into the air. The cap fell 7m(23ft) away from the desander. No workers were injured.
