1. Field of the Disclosure
This disclosure relates generally to apparatus for use in wellbore operations that utilize progressive cavity power devices.
2. Background of the Art
To obtain hydrocarbons, such as oil and gas, boreholes or wellbores are drilled by rotating a drill bit attached to a drill string end. A large number of the current drilling activity involves drilling deviated and horizontal boreholes for hydrocarbon production. Current drilling systems utilized for drilling such wellbores generally employ a motor (commonly referred to as a “mud motor” or “drilling motor”) to rotate the drill bit. A typical mud motor includes a power section that includes a rotor having an outer lobed surface disposed inside a stator having a compatible inner lobed surface. The power section forms progressive cavities between the rotor and stator lobed surfaces. Also, certain pumps used in the oil industry utilize progressive cavity power sections. The rotor is typically made from a metal, such as steel, and includes helically contoured lobes on its outer surface. The stator typically includes a metal housing lined inside with an elastomeric material that forms helical contours or lobes on the inner surface of the stator. For high temperature applications, metal rotor and metal stator motors have been proposed. Pressurized fluid (commonly known as the “mud” or “drilling fluid”) is pumped into the progressive cavities formed between the rotor and stator lobes. The force of the pressurized fluid pumped into the cavities causes the rotor to turn in a planetary-type motion.
The disclosure herein provides progressive cavity devices, such a mud motors and pumps, that include serially coupled independent power sections or stages.