Adoption of managed pressure drilling (MPD) technologies of the applied surface backpressure type in deepwater environments have mainly involved a rotating control device (RCD) to create a closed drilling system where flow out of the well is diverted towards and backpressure regulated using an automated MPD choke manifold with a high-resolution mass flow meter that increases sensitivity and reaction time to kicks, losses and other unwanted drilling events.
This integration of MPD equipment into floating drilling rigs to provide it with MPD capabilities, including the capacity to perform pressurized mud cap drilling (PMCD) and riser gas mitigation (RGM), has not only produced improvements in terms of drillability and efficiency, but most importantly, in terms of process safety.
Case histories on how MPD has performed will be presented on the following:
• allowed drilling to reach target depth in rank wildcat deepwater wells that have formations prone to severe circulation losses and narrow mud weight windows;
• increased drilling efficiency by minimizing non-productive time associated with downhole pressure-related problems and by allowing for the setting of deeper casing seats;
• enhanced operational and process safety by allowing for immediate detection of kicks, losses and other critical downhole events.
• provided riser gas mitigation capabilities that can detect a gas influx once it enters the drilling fluid stream, and not after it has already broken out above the rig blow-out preventers (BOPs).