Return Flow Control
MPD technique which diverts returned fluid flow away from the rig floor in order to handle any formation fluid influx, thereby avoiding closing of a BOP, with the subsequent well control steps that are customarily required. RFC is drilling with a closed annulus return system (RCD) immediately under the rig floor for complete assurance of the total diversion of any rapidly developing kick.
Source: ABS Guide for Classification and Certification of Managed Pressure Drilling Systems, September 2017. Global Standards