Abstract: A method of controlling pressure in a wellbore can include determining a desired position for a choke, the determining being based on a Cv curve for the choke, and adjusting the choke to the desired position, thereby producing a desired backpressure. A wellbore drilling system can include a choke which variably restricts flow of fluid from the wellbore, and a control system which compares actual and desired wellbore pressures and, in response to a difference between the actual and desired wellbore pressures, adjusts the choke to a predetermined position which corresponds to a desired Cv of the choke. A method of controlling pressure in a wellbore can include comparing an actual wellbore pressure to a desired wellbore pressure and, in response to a difference between the actual and desired wellbore pressures, adjusting a choke to a predetermined position, the predetermined position corresponding to a desired Cv of the choke.

Abstract: A well drilling system and method to balance multiple equivalent circulating density (“ECD”) targets along a wellbore during drilling.

Abstract: A method of controlling pressure in a wellbore can include determining a desired position for a choke, the determining being based on a Cv curve for the choke, and adjusting the choke to the desired position, thereby producing a desired backpressure. A wellbore drilling system can include a choke which variably restricts flow of fluid from the wellbore, and a control system which compares actual and desired wellbore pressures and, in response to a difference between the actual and desired wellbore pressures, adjusts the choke to a predetermined position which corresponds to a desired Cv of the choke. A method of controlling pressure in a wellbore can include comparing an actual wellbore pressure to a desired wellbore pressure and, in response to a difference between the actual and desired wellbore pressures, adjusting a choke to a predetermined position, the predetermined position corresponding to a desired Cv of the choke.

Abstract: A well drilling method can include sensing at least one of audio and optical signals, generating a parameter signature during a drilling operation, the parameter signature being based at least in part on the sensing, and detecting a drilling event by comparing the parameter signature to an event signature indicative of the drilling event. A well drilling system can include a control system which compares a parameter signature for a drilling operation to an event signature indicative of a drilling event, the parameter signature being based at least in part on an output of at least one audio and/or optical sensor, and a controller which controls the drilling operation in response to the drilling event being indicated by at least a partial match between the parameter signature and the event signature.

Abstract: A method of controlling pressure in a wellbore can include determining a desired well pressure setpoint, adding an offset to the setpoint in response to an actual well pressure deviating from the setpoint by a predetermined amount, and adjusting a flow control device, thereby influencing the actual well pressure toward the setpoint plus the offset. A well system can include a flow control device which variably restricts flow from a wellbore, and a control system which determines a desired well pressure setpoint, compares the setpoint to an actual well pressure, and adds an offset to the setpoint in response to a predetermined amount of deviation between the setpoint and the actual well pressure, whereby the control system adjusts the flow control device, and thereby influences the actual well pressure toward the setpoint plus the offset.