Controlled pressure drilling system with flow measurement and well control

An apparatus for controlled pressure drilling of a wellbore, the apparatus comprising:

• a plurality of flowmeters in parallel fluid communication;
• and
• a distributor in fluid communication between the wellbore and the plurality of flowmeters and operable to selectively direct drilling fluid flow from the wellbore to one or more of the plurality of flowmeters,
• wherein the distributor comprises a plurality of first valves each in fluid communication upstream of a respective one of the flowmeters, and
• wherein each of the first valves is operable to control upstream pressure in the drilling fluid flow.

An apparatus for controlled pressure drilling of a wellbore, the apparatus comprising:

• a plurality of flowmeters in parallel fluid communication;
• a distributor in fluid communication between the wellbore and the plurality of flowmeters and operable to selectively direct drilling fluid flow from the wellbore to one or more of the plurality of flowmeters;
• one or more first valves in fluid communication with the drilling fluid flow;
• and
• a control in operable communication with the flowmeters and the one or more first valves, the control obtaining a reading from the one or more selected flowmeters and controlling, with the one or more first valves, upstream pressure in the drilling fluid flow based at least in part on the obtained reading.

A method of drilling a wellbore with a drilling system, the method comprising:

• obtaining a measurement of drilling fluid flow from the wellbore;
• controlling, with one or more first valves of the drilling system, upstream pressure of the drilling fluid flow in the wellbore based at least in part on the obtained measurement;
• and
• selectively distributing the drilling fluid flow from the wellbore through one or more of a plurality of flowmeters based at least in part on the obtained measurement by comparing a pressure of the obtained measurement to a pressure capacity of each of the flowmeters and determining which of the one or more of the plurality of flowmeters to select for distribution based on the comparison.

An apparatus for controlled pressure drilling of a wellbore, the apparatus comprising:

• a plurality of flowmeters in parallel fluid communication;
• and
• a distributor in fluid communication between the wellbore and the plurality of flowmeters and operable to selectively direct drilling fluid flow from the wellbore to one or more of the plurality of flowmeters, the distributor comprising:
• a plurality of first valves each in fluid communication upstream of a respective one of the flowmeters;
• and
• a plurality of second valves each in fluid communication downstream of a respective one of the flowmeters, each of the second valves being operable to control pressure in the respective one of the flowmeters.

A method of drilling a wellbore with a drilling system, the method comprising:

• obtaining a measurement of drilling fluid flow from the wellbore;
• controlling, with one or more valves of the drilling system, upstream pressure of the drilling fluid flow in the wellbore based at least in part on the obtained measurement by operating at least one first of the one or more valves upstream of at least one of the one or more selected flowmeters to adjust the upstream pressure;
• selectively distributing the drilling fluid flow from the wellbore through one or more of a plurality of flowmeters of the drilling system based at least in part on the obtained measurement;
• and
• adjusting internal pressure at least inside the at least one selected flowmeter using at least one second of the valves downstream of the at least one selected flowmeter in response to the adjustment of the at least one first valve.