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WELL CONTROL EVENT WHILE USING MANAGED PRESSURE DRILLING EQUIPMENT
Incident Date: --- Time: ---
Type of Activity: Drilling, workover, well services
Type of Injury: ---
Drilling deep chalk section of a high-pressure, high-temperature well. Phase drilled with 1.95SG mud effective density exerted (ECD) required at 1.99SG due to increase of gas. Managed pressure drilling (MPD) system in place used for applying back pressure during drilling and at connections. Observed some dynamic losses – perform dynamic formation integrity test (FIT) indicated 2.01eSG maximum permissible. Drilling continued managing ECD ~1.99SG but gas behaviour increased. Dynamic losses resumed, attempted to cure same - observe influx, attempt to control with MPD back pressure then shut well in. 3m3 of gain / downhole crossflow developed between reservoir and thief zone.
What Went Wrong?:
Corrective Actions and Recommendations:
Use of MPD permits drilling phases with very narrow mud weight window, however:
safety alert number: 299
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