Inertial compensation for a quill oscillator
AssigneeEnsign Drilling Inc.
InventorsJarrod David Chapman, Chiranjit Saha, Sean Timothy Halloran
Life of this patent
Estimating the term…
Abstract
A drilling system configured to reduce friction during slide drilling. The drilling system has a drill string comprising a fluid-driven drill stage such as a mud motor; a variable frequency drive configured to oscillate the drill string via a quill and a sensor array. The sensor array measures the torque applied to the quill and the angular position of the quill. A controller is used to control the variable frequency drive based on the determined applied torque and quill angular position to meet predetermined oscillation turn-around criteria and to reduce the time to reduce the angular velocity of the quill from a maximum rotational speed to zero in an oscillation cycle.
Claims20
A drilling system for oscillating a drill string having a fluid-driven drill stage, the drilling system comprising:
- a top drive comprising a variable frequency drive configured to repeatedly oscillate the drill string via a quill during slide drilling, wherein each oscillation of the drill string includes a clockwise oscillation cycle and a counter-clockwise oscillation cycle;
- a sensor array having a sensor configured to determine a measure of torque applied to the quill;
- a controller configured to receive information from the sensor array and to determine the angular position and speed of the quill and the inertia applied to the quill by the drill string,
- wherein the controller is configured to enable ongoing control of the variable frequency drive while decreasing the angular velocity of the quill from a maximum rotational speed to zero in an oscillation cycle, the zero rotational speed corresponding to a turn-around point in the oscillation where the variable drive stops rotating in one direction and starts rotating in the opposite direction;
- the ongoing control comprising adaptively adjusting control parameters of the variable drive in real time in response to the determined applied inertia and the angular position and speed of the quill, and being configured to reduce the time to decrease the angular velocity of the quill from the maximum rotational speed to zero in the oscillation cycle and to meet predetermined oscillation turn-around criteria.
A method of controlling a drilling system, the drilling system comprising:
- a drill string comprising a fluid-driven drill stage;
- a top drive comprising a variable frequency drive configured to repeatedly oscillate the drill string via a quill during slide drilling, wherein each oscillation of the drill string includes a clockwise oscillation cycle and a counter-clockwise oscillation cycle;
- a sensor array having a sensor configured to determine a measure of torque applied to the quill;
- a controller configured to receive information from the sensor array and to determine the applied torque, and the angular position and the angular speed of the quill,
- wherein the method comprises:
- controlling the variable frequency drive during slide drilling on an ongoing basis while decreasing the angular velocity of the quill from a maximum rotational speed to zero in an oscillation cycle, the zero rotational speed corresponding to a turn-around point in the oscillation cycle where the variable drive stops rotating in one direction and starts rotating in the opposite direction;
- the ongoing control comprising adaptively adjusting control parameters of the variable drive in real time in response to a determined applied inertia and the angular position and speed of the quill and being configured to reduce the time to decrease the angular velocity of the quill from the maximum rotational speed to zero in the oscillation cycle and to meet predetermined oscillation turn-around criteria.
Dependencies are inferred from the claim text.