Managed pressure drilling — what's in a name? Definition is secondary to technology's applications

In non-technical terms, the simplest yet most compelling definition of managed pressure drilling is “cheating Mother Nature.” As most drillers learn on the first day of their careers, bottomhole pressure is normally maintained above pore pressure by simply controlling the density of the drilling fluid. When density gets too high, the formation begins to drink fluid and it’s time to stop. Casing must be run to isolate the open hole before drilling can continue. This relationship is shown graphically in Figure 1.