Undercured stator for mud motor
AssigneeSchlumberger Technology Corporation
InventorsAnton Kolyshkin, Lillian Guo, Yuxiang Liu, Miranda Amarante
Life of this patent
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Abstract
A stator for a mud motor and methods for manufacturing and using the same, of which one such method includes obtaining a mud motor having a stator made at least partially from a rubber. At least a portion of the rubber is cured by at most about 90%. The method also includes deploying the mud motor into a well as part of a drill string. The rubber is not further cured prior to deploying the mud motor into the well. The method further includes generating torque using the mud motor by pumping a mud through the stator.
Claims19
A stator for a mud motor, the stator comprising a body made at least partially from a rubber, wherein the rubber has an amount of curing that varies circumferentially along an inner surface and does not vary circumferentially along an outer surface, wherein the amount of curing is between about 50% and at most 90% cured such that a fatigue life of the rubber at the about 50% cured is higher than the fatigue life of the rubber the at most 90% cured, the inner surface further defining a bore through the body wherein the inner surface is configured to cooperate with a rotor and to receive a drilling fluid therethrough.
A method for manufacturing a stator for a mud motor, the method comprising:
- positioning a rubber body in a mold comprising a tube and a core, such that the rubber body defines a helical inner bore about the core, wherein the rubber body is substantially uncured;
- selecting, based at least in part on fatigue life of the rubber body, a curing percentage for at least a portion of the rubber body prior to heating the rubber body;
- curing the rubber body at a temperature and for a time sufficient to cure at least the portion of the rubber body by the curing percentage, wherein the curing percentage is between about 50% and at most about 90%;
- allowing the rubber body to cool so as to maintain the portion of the rubber body at between about 50% and about 90% cured, wherein the rubber body is cured less at an inner bore thereof than at an outer surface thereof, and the inner bore is configured to cooperate with a rotor of the mud motor;
- and
- removing the core of the mold from the rubber body.
A method, comprising:
- obtaining a mud motor having a stator made at least partially from a rubber, wherein at least a portion of the rubber at an inner surface of the stator is cured by between about 50% and at most about 90% selected based at least in part on fatigue life of the rubber, wherein the inner surface defines a bore through the stator;
- deploying the mud motor into a well as part of a drill string, wherein the rubber is not further cured prior to deploying the mud motor into the well;
- and
- generating torque using the mud motor by pumping a mud through the bore of the stator.
Dependencies are inferred from the claim text.