초록 ▼

A downhole tool containing instruments and a pulser is landed within a string of drill pipe. The pulser has a pulser body and an orifice on a lower end. A piston slides within a bore in the body and has a signal poppet on a lower end. In an extended position, the signal poppet extends into and obstr

A downhole tool containing instruments and a pulser is landed within a string of drill pipe. The pulser has a pulser body and an orifice on a lower end. A piston slides within a bore in the body and has a signal poppet on a lower end. In an extended position, the signal poppet extends into and obstructs the orifice to reduce the flow of drilling fluid. In an open position, the signal poppet does not obstruct the orifice to increase the flow of drilling fluid. A bidirectional solenoid valve is located above the piston and has upper and lower electromagnetic coils and an axially moveable rod. The rod is movable between a closed position in an opening in the body and an open position away from the opening. The rod is moved to both positions in response to the instruments which sends signals to the coils. The mud pulser also has an on/off flow switch which is actuated by the commencement of mud circulation. Initially, the rod is in the closed position. The instruments take various measurements which are communicated through the pulser to the surface in the form of mud pulses. A mud pulse is generated when a coil is energized to move the rod to the open position. This forces the piston and signal poppet into the extended position to restrict mud flow. The rod is moved to the closed position when the other coil is energized. The signal poppet creates pulses which are detected at the surface.

대표청구항 ▼

[ I claim:] [1.] A downhole mud pulser for creating pressure pulses in a stream of drilling fluid being circulated through a drill string, the mud pulser responding to electrical signals provided by a measuring instrument coupled to the mud pulser, the mud pulser comprising:a pulset body adapted to

[ I claim:] [1.] A downhole mud pulser for creating pressure pulses in a stream of drilling fluid being circulated through a drill string, the mud pulser responding to electrical signals provided by a measuring instrument coupled to the mud pulser, the mud pulser comprising:a pulset body adapted to be connected into the drill string so as to define a main flow passage for the passage of drilling fluid;an orifice adapted to be mounted in the drill string through which drilling fluid from the main flow passage is adapted to flow;a tubular signal poppet having an annular piston reciprocally carried within the body and having a lower end which extends into the orifice to restrict flow and create a mud pulse while in an extended position, and which moves upward from the orifice to increase flow while in an open position;an inner passage in the body extending through the piston and the signal poppet for the passage of drilling fluid from the main flow passage;a port in the body leading from the main flow passage to a point below and in communication with the piston for supplying pressure from the drilling fluid;an upward facing servo seat in the inner passage;an axially movable servo poppet in the inner passage which moves between a closed position in engagement with the seat for blocking flow through the inner passage and an open position for allowing flow through the inner passage; anda bi-directional solenoid having a first coil, a second coil, and a rod extending within the coils, the servo poppet being connected to the rod for movement therewith, the coils being adapted to be electrically connected to the instrument, wherein the first coil, when engerized by one of the signals, moves the rod and the servo poppet to the open position which causes the signal poppet to move to the extended position for creating a mud pulse, and the second coil, when energized by another one of the signals, moves the rod and the servo poppet to the closed position which causes the signal poppet to move to the open position.