Patent ID: 7278496

Claim:
A system for operating a well having a fluid flow path defined by an injection line ( 14 , 22 ) through which an inlet stream flows and a return line ( 27 ) through which an outlet stream flows, the system including, a pressure containment device ( 26 ) applied to the wellbore so that while the well is being drilled with a drill string ( 1 ) having a drilling liquid circulated therethrough, the well is kept closed from atmosphere at all times, means ( 10 , 11 , 15 , 16 , 28 a , 28 b ) in said injection line ( 14 , 22 ) and said return line ( 27 ) for measuring actual mass or actual fluid flow rate of liquid in the inlet and outlet streams to obtain actual mass or fluid flow signals, at least one pressure sensor ( 9 , 17 , 24 , 28 c ) in said fluid flow path to obtain an actual pressure signal, a central data acquisition and control system ( 18 ) which receives said actual mass or fluid flow signals and said actual pressure signals, software installed in said central data acquisition and control system ( 18 ) which determines a real time ideal signal during drilling of the well, a control device ( 12 ) arranged and designed to apply backpressure to the wellbore, said software further arranged and designed to make a comparison between said real time ideal signal and a corresponding actual signal, said comparison yielding any discrepancy between said real time ideal signal and said corresponding actual signal, said software converting said discrepancy to a command value signal, and means for applying said command value signal to said control device ( 12 ) to adjust backpressure in the wellbore so that said actual signal is restored to said ideal signal, said software further arranged and designed to provide identification of an influx or loss event and, based on such identification, pre-emptively send a signal to said control device, thereby pre-emptively adjusting backpressure to immediately control the event without interruption of drilling operations.