Safety rules of snubbing operation are :
- Personal climbing to or working at a height from which a fall could be dangerous, should wear safety hardness or other equivalent equipment.
- The work basket should be equipped with an emergency escape system which will enable personal to reach the ground at some distance from the well but not at a dangerous speed.
- Periodic escape routes should be simple.
- If snubbing unit is rigged up on a well, where stripper only is being used, each BOP should be opened / closed at least once every three days to prevent corrosion or formation of deposits around the rams.
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| Safety First |
- In a gas well situation, the following additional equipment is highly recommended :
- Guide tubes for all the necessary size if workstring to prevent buckling during the light phase.
- Injection of grease between the 2 rubbers of the stripping bowl lubricates the workstring allows to work in a safer way and reduces the time spent in snubbing with the ram to ram technique.
- There must be a hole open between lower stripper and BOP to prevent pressure build up at stripper.
- A choke (usually 1/4") is to be fitted in equalizing loop to reduce the stress encountered during the operation.
- All BOP wing valves should be doubled, the second ones is for back up.
- BOP stack must include shear and blind rams.
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- If a job cannot be terminated before night, the following procedure should be implemented to keep the snubbing unit and well "safe" overnight.
- Positive mechanical locking of the BOP rams after they have been closed hydraulically.
- Bleed off pressure between BOP's.
- Bleed off pressure from stripper bowl only the stripping BOP will be closed, locked and bled off as above. The safety BOP will only be used in case of a leak through the stripping BOP.
- Close all slips bowl and mechanically lock using an appropriate system.
- Periodically check and grease (special bitumen grease) the cables.
- Never use stripper rubber when using stripping BOP's.