Rotary servo pulser and method of using the same

摘要

A servo pulser used to actuate a pulser valve and create pressure pulses in downhole measurement while drilling tools is described. An electric gearmotor is used to rotate a shaft which in turn operates a servo valve. A facing portion of the shaft is compressed onto the face of a servo seat having passages connected to the inside of a drill collar and the rotating action is used to open and/or obstruct a fluid path through those passages. The shaft may include wear-resistant tips to obstruct the fluid path. Part of the torque-transmitting apparatus between the gearmotor and the shaft can be hydrostatically compensated, and part sealed against the operating environment. A magnetic torque coupler may be used as part of the torque-transmitting apparatus between the gearmotor and the shaft. The servo pulser is coupled to a pulser valve, a power source and a sensor package all of which reside inside a short section of drill pipe near the bottom of well bore being drilled.

主权项

1. A rotary servo valve for actuating a mud pulser in a drilling fluid column, comprising:
a servo valve seat defining one or more drilling fluid passageways therethrough; the rotary servo valve being capable of operating in at least two rotational positions, including a first rotational position in which the rotary servo valve blocks said one or more drilling fluid passageways; and at least one rotational stop defining one of said rotational positions; said at least one rotational stop positioned wholly radially outward of said valve seat; said at least one rotational stop being an extension of a retaining structure for said valve seat; said at least one rotational stop indirectly contacting said valve seat and being in a fixed rotational orientation thereto; and an obstructing portion comprising two or more tips extending axially from said obstructing portion toward the servo valve seat.