DRILLING SYSTEM CONTROL

摘要

A method for controlling a drilling system comprising a drive system, drillstring and drill bit. The drive system rotates the drillstring during a drilling process to drill a borehole through an earth formation. The method involves setting a desired rotation speed v0 for the drillstring; receiving property measurements of the drilling system and deriving therefrom the component vup of the rotation speed of the drillstring associated with upgoing rotational energy; determining a rotation speed v for the drillstring by optimizing an expression which reconciles two conflicting objectives of: (i) maintaining a stable rotation speed centred on v0, and (ii) minimizing the downgoing rotational energy, the optimized expression expressing v in terms of v0 and vup; and controlling the drive system to rotate the drillstring at v.

主权项

1. A method for controlling a drilling system comprising a drive system, drillstring and drill bit, wherein the drive system rotates the drillstring during a drilling process to drill a borehole through an earth formation, the method comprising:
setting a desired rotation speed v0 for the drillstring; receiving property measurements of the drilling system and deriving therefrom a component vup of a rotation speed of the drillstring associated with upgoing rotational energy; determining a rotation speed v for the drillstring by optimizing an expression which reconciles two conflicting objectives of: (i) maintaining a stable rotation speed centered on v0, and (ii) minimizing downgoing rotational energy, the optimized expression expressing v in terms of v0 and vup; and controlling the drive system to rotate the drillstring at v.