To avoid problems with under gauge hole and BHA changes it is important to ensure the following to reduce the riskof stuck pipe:
- bits and stabilisers shall always be gauged after each trip
- if the bit pulled is undergauge, the whole of the section drilled by that bit is reamed unless torque records clearly show the point at which the bit gauge became worn
- BHA’s of increased stiffness are not tripped into the hole rapidly - reaming is recommended
- if the hole is suspected to be undergauge, extreme caution is applied when tripping into the hole (if in doubt, reaming shall be carried out)
- the hole is reamed prior to picking up LWD or changing to a stiffer BHA/LWD, (this is unnecessary if the hole is to be drilled with the same BHA as used from the start).