Viscous vibration damping of torsional oscillation
AssigneeBaker Hughes Oilfield Operations LLC
InventorVolker Peters
Life of this patent
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Abstract
An apparatus for damping vibrations includes an inertial mass disposed in a cavity in a rotatable downhole component, the rotatable component configured to be disposed in a borehole in a subsurface formation, such as a resource bearing formation, the inertial mass coupled to a surface of the cavity by a damping fluid and configured to move within the cavity relative to the downhole component. The apparatus also includes a damping fluid disposed in the cavity between the inertial mass and an inner surface of the cavity, where rotational acceleration of the rotatable downhole component causes shear in the damping fluid to dissipate energy from rotational acceleration of the rotatable downhole component and causing the rotational acceleration to be reduced.
Claims23
An apparatus for damping torsional vibrations in a borehole string, the apparatus comprising:
- a plurality of inertial masses disposed in a cavity in a rotatable downhole component, the rotatable downhole component configured to be disposed in a borehole in a subsurface formation, wherein each inertial mass of the plurality of inertial masses includes a ring or a ring segment, the plurality of inertial masses are coupled to the rotatable downhole component by a damping fluid, and the plurality of inertial masses are free to move relative to the rotatable downhole component such that a full rotation of each inertial mass of the plurality of inertial masses relative to the rotatable downhole component is permitted, wherein the plurality of inertial masses are arrayed along a rotational axis of the rotatable downhole component and are configured to rotate about the rotational axis of the rotatable downhole component;
- wherein
- the damping fluid is disposed in the cavity and between the plurality of inertial masses and the rotatable downhole component, wherein rotational acceleration of the rotatable downhole component causes shear in the damping fluid to dissipate energy from the rotational acceleration of the rotatable downhole component and causes the rotational acceleration of the rotatable downhole component to be reduced.
A method of damping torsional vibrations in a borehole string, the method comprising:
- disposing a rotatable downhole component and a damping assembly in a borehole in a subsurface formation, the damping assembly including a cavity that is rotationally fixed relative to the rotatable downhole component, and a plurality of inertial masses disposed in the cavity and coupled to the rotatable downhole component by a damping fluid disposed between at least one of the plurality of inertial masses and the rotatable downhole component, wherein each inertial mass of the plurality of inertial masses includes a ring or a ring segment, and the plurality of inertial masses are free to move relative to the rotatable downhole component such that a full rotation of each of the plurality of inertial masses relative to the rotatable downhole component is permitted, wherein the plurality of inertial masses are arrayed along a rotational axis of the rotatable downhole component and are configured to rotate about the rotational axis of the rotatable downhole component;
- performing an operation that includes rotating the rotatable downhole component and causing the torsional vibrations of the rotatable downhole component;
- and
- damping at least partially the torsional vibrations of the rotatable downhole component, wherein the damping includes causing rotational acceleration of the rotatable downhole component to be reduced based on shear occurring in the damping fluid due to relative movement between the plurality of inertial masses and the rotatable downhole component.
Dependencies are inferred from the claim text.