Volumetric Drift Catcher - Drifting pipe with health and safety in the hole Risk Assessment drift in derrick or elevators BHA connection

Safer liner cementing with pump stroke calibration whilst drifting

Summary

Run Drift Catcher sub as normal
At TD pump the wiper drift instead of sleeve
Burst disc will release pressure spike to surface
Drift and volume confirmed simultaneously

Pumping the volumetric drift will provide an accurate indication of the number of strokes that will be required to displace the cement through the drill pipe volume. This will be vital information for cementing job if no bump(s) observed to indicate landing of the plugs at the liner foot.

Under-displacement is the safe option but if left too short a void zone outside the liner will compromise productivity and milling of the excess internal cement will be required during the cleanout.

Worst case scenario is that over-displacement leaves a void interface into payzone because accurate pump volumes were not known.

Method

Pump down wiper drift accessory
Observe disc bursting on landing
Reference volume to pump strokes

Benefits

Reduced risk of over-displacement
Reduced risk of under displacement
Pressure confirmation of drift at surface