MPD is an enabling technology focused mainly on applying the benefits of performance drilling to offshore drilling applications. The intent is not to invite a true state of underbalanced conditions; rather, it is to more precisely manage/control/contain annulus returns. MPD may be accomplished by many means including combinations of backpressure, variable fluid density, fluid rheology, circulating friction, and hole geometry.
Containment used in this context means that MPD is focused not on
creating a pressure draw down across formations, which may produce
hazardous flow products, but instead to contain any flow incidental to
the operation.
LEA has recently completed on behalf of Shell EPE the successful
introduction of MPD to their Shell Gannet Alpha Asset – the first such
operation to be undertaken in the UKCS.