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BARRIER VERIFICATION MISSED: OPEN FLUID LOSS VALVE LEADS TO WELL CONTROL INCIDENT
Incident Date: --- Time: ---
Type of Activity: Drilling, workover, well services
Type of Injury: ---
The incident occurred during the final stages of the completion of a horizontal screen producing well.
The installation of lower completion was completed and the liner top packer was successfully set and pressure tested.
The remaining program steps were to place a base oil cushion above the closed fluid loss valve to create an under-balanced condition to support production kick off.
The path for the brine to base oil displacement was from the cement unit, down the tubing string, through a ported sub installed above the completion packer and then up the annulus. Brine returns were discharged overboard until a dyed interface was observed. The intention was to displace the entire well (tubing and annulus volume) above the fluid loss valve to base oil (+/-125m³).
The well displacement to base oil commenced once the tubing hanger was landed, latched, and over-pulled. When displacement was complete, flow was observed to continue from the well. The Driller shut-in at the surface choke and monitored the wellbore pressures on the tubing and annulus. It was estimated that an influx of 23m³ had entered the well.
The influx was bullheaded back into the formation by pumping base oil from the cement unit.
What Went Wrong?:
Corrective Actions and Recommendations:
safety alert number: 274
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