Patent ID: 9016381
Filing Date: 2015-04-28
Classification: E21B,Y10T

Abstract:
1. A system for controlling flow in a subsea wellhead comprising: a blowout preventer (BOP) on the wellhead having an axial bore that receives a drill string; an annular space defined between the drill string and an inner surface of the BOP and through which mud exiting the wellhead selectively flows; a sensor in the annular space for sensing a parameter of the mud; a valve comprising a ram block in the BOP that selectively moves into and out of the annular space; an actuator for moving the ram block; and a controller that estimates a degree of opening the valve, and that controls operation of the actuator that regulates the flow of the mud based on the values acquired by the sensor having the ram blocks moved into the annular space to reduce the flow of mud through the BOP and having the ram blocks moved out of the annular space to increase the flow of mud through the BOP.