Prior to cementation, it is recommended to circulate at least 150 % of the casing volume.
During the circulation the circulating pressures at different pumping rates to be recorded for each pump.
Recommended to start circulation at a very low rate and gradually increase in increments of 2bpm.
Prudent to wait 5 min for observing losses and for pressures to stabilize prior recording.
Take the opportunity to ensure all PVT instrumentation are functional and cross check with manual level measurements.
Compare between calculated pump discharges and actual fluid pumped by directing returns to a known volume pill tank.(assuming no losses/gain).
Reduce the pump rate if losses are observed or at max ECD allowable.
Determine the final cement slurry displacement rate and note the circulation pressures at this rate.
The circulation test basically guides one to choose the appropriate circulation rates for cement displacement, pump volumetric efficiencies and the detection of pressure peak on bumping plug(if used) and/or to avoid over displacement.