If well kicks while tripping and the well is shut in, wait for instructions from the Drilling Superintendent. All equipment shall be arranged to implement the stripping operation. This means that:
- it shall be possible to accurately measure any mud volume released from the well
- accurate pressure gauges should be available
- pressure regulators on blow out preventers should be in good working order
- the equipment and procedures to be used during volumetric stripping should be understood to at least Driller's level and practised regularly.
Even if stripping cannot for some reason be considered, well control has to be maintained while decisions are made regarding well killing method to be employed. It is therefore essential that rigs are suitably rigged-up to implement the volumetric method.
The annular preventer is usually used for stripping pipe into or out of the hole as it permits the tool joints to pass through the packing element. To minimise wear, the pipe should be well lubricated with grease and the closing pressures on the annular preventer should be kept to the minimum. If leakage does occur, it shall be accurately measured and added to total volume released from the well.
Some types of annular preventers (i.e. Hydril) are more difficult to adjust as the well pressure assists in closing the element around the pipe. As the pressures become higher it will be more difficult to strip the tool joints through the packing element. To reduce this friction, a nitrogen charged bag type accumulator should be installed in the hydraulic closing line as near to the preventer as possible.
Volumetric Stripping Procedures
The detailed procedures and calculations on how to perform a volumetric stripping operation is described in a separate article (see "related articles" on the right column).
A record of pressures and volumes shall be kept throughout the stripping exercise.
Once on bottom, the well should be killed using the “Drillers” or “Wait and Weight” Method.