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US 9,869,126 B2Granted
Variable diameter stator and rotor for progressing cavity motor
AssigneeNabors Drilling Technologies USA, Inc.
InventorNigel Evans
Life of this patent
Estimating the term…
Abstract
A mud motor for use in a wellbore may include a stator and rotor. The tolerance between the stator and rotor may be varied along the length of the mud motor to, for example, reduce wear of the stator at predetermined locations. The tolerance may range from an interference fit to a clearance fit. The tolerance may vary multiple times across the length of the mud motor.
Claims12
A mud motor for use in a wellbore, the mud motor comprising:
- a rotor, the rotor including at least one helical rotor lobe extending therefrom;
- a stator, the stator being tubular in shape and including at least two helical stator lobes extending inward from an inner surface thereof, the at least two helical stator lobes interfacing with the at least one helical rotor lobe to create at least one cavity between the stator and the rotor such that the cavity traverses the length of the stator as the rotor eccentrically rotates within the stator;
- wherein the distance between the stator and the rotor at an interface between the at least two helical stator lobes and the at least one helical rotor lobe at a given point along the mud motor defines a tolerance;
- and
- wherein the rotor and the stator are formed such that the tolerance at a first point along the mud motor is wider than the tolerance at a second point along the mud motor, wherein the first point along the mud motor is positioned nearer the upper end of the mud motor than the second point along the mud motor.
2 more elements
A mud motor for use in a wellbore, the mud motor comprising:
- a rotor, the rotor including at least one helical rotor lobe extending therefrom;
- a stator, the stator being tubular in shape and including at least two helical stator lobes extending inward from an inner surface thereof, the at least two helical stator lobes interfacing with the at least one helical rotor lobe to create at least one cavity between the stator and the rotor such that the cavity traverses the length of the stator as the rotor eccentrically rotates within the stator;
- wherein the distance between the stator and the rotor at an interface between the at least two helical stator lobes and the at least one helical rotor lobe at a given point along the mud motor defines a tolerance;
- and
- wherein the rotor and the stator are formed such that:
- the tolerance at a first point along the mud motor is wider than the tolerance at a second point along the mud motor;
- and
- the tolerance at a third point along the mud motor is wider than the tolerance at the second point along the mud motor;
- wherein the second point along the mud motor is positioned between the first point along the mud motor and the third point along the mud motor.
6 more elements
A mud motor for use in a wellbore, the mud motor comprising:
- a rotor, the rotor including at least one helical rotor lobe extending therefrom;
- a stator, the stator being tubular in shape and including at least two helical stator lobes extending inward from an inner surface thereof, the at least two helical stator lobes interfacing with the at least one helical rotor lobe to create at least one cavity between the stator and the rotor such that the cavity traverses the length of the stator as the rotor eccentrically rotates within the stator;
- wherein the distance between the stator and the rotor at an interface between the at least two helical stator lobes and the at least one helical rotor lobe at a given point along the mud motor defines a tolerance;
- and
- wherein the rotor and the stator are formed such that:
- the tolerance at a first point along the mud motor is wider than the tolerance at a second point along the mud motor;
- and
- the tolerance at a third point along the mud motor is tighter than the tolerance at the first point along the mud motor;
- wherein the first point along the mud motor is positioned between the second point along the mud motor and the third point along the mud motor.
6 more elements
Dependencies are inferred from the claim text.