METHOD AND SYSTEM FOR CONTROLLING WELL BORE PRESSURE

Methods and systems are provided for maintaining fluid pressure control of a well bore 30 drilled through a subterranean formation using a drilling rig 25 and a drill string 50, whereby a kick may be circulated out of the well bore and/or a kill fluid may be circulated into the well bore, at a kill rate that may be varied. A programmable controller 100 may be included to control execution of a circulation/kill procedure whereby a mud pump 90 and/or a well bore choke 70 may be regulated by the controller. One or more sensors may be interconnected with the controller to sense well bore pressure conditions and/or pumping conditions. Statistical process control techniques may also be employed to enhance process control by the controller. The controller 100 may further execute routine determinations of circulating kill pressures at selected kill rates. The controller may control components utilized in the circulation/kill procedure so as to maintain a substantially constant bottom hole pressure on the formation while executing the circulation/kill procedure.