The Compass Positive Stepper Pulser generates a sequence of pressure increment pulses in the circulating system, enabling the transmission of MWD data recorded downhole to surface.

compass stepper pulser

The tool is fully retrievable and replaceable, which saves rig time by eliminating pipe trips for directional equipment.

The Compass Pulser Module consists of 3 main sections: pulser driver, oil fill, and helix end. The pulser allows mud flow to be restricted, creating a pressure differential by way of a main orifice poppet/orifice assembly. The movement of the main poppet in and out of the orifice creates an increase in pressure. The two factors that greatly affect poppet movement are the operation of the electrical section of the module and the fluid pressure on the compensation membrane.

The Compass pulser is designed to “drop-in” place of the Tensor solenoid pulser and therefore operates similar to the design. The Compass pulser uses a stepper motor as the driver to actuate the servo poppet in the creation of the mud pulse.  A stepper motor is designed to rotate in “steps” as energy is pulsed to it during operation.  A small capacitor stores energy to be sent to the motor in measured sequences and amounts.  These energy transmissions allow the motor to rotate precisely.  The energy transmissions are controlled by a small processor to ensure the exact timing and amount of rotation.  This control allows the mechanism to rotate the shaft connected to the servo poppet an exact amount to allow the servo poppet to open at a precise measure and allow flow through the servo orifice.  The stepper motor is then reversed with the same precise actuation to close and complete the pulse sequence.

compass pulser motor


    • Simple to operate under a wide range of flow rates
    • Operable in lost circulation material concentrations of 30-50 lb/bbl medium nut plug
    • Servo technology for faster data rates, stronger signal, and superior anti-jamming capabilities for reliable data transmission in difficult drilling
    • Exceptionally power-efficient with battery life of up to 420 hoursstepper pulser driver
Length 86" (2.18 m)
Weight 35 lb (15.9 kg)
Min Flow Rate 35 gpm (8 L/sec)
in water
Max Flow Rate 1,100 gpm (67 L/sec) in water
Max Operating Temp 175°C (350°F)
Max Hydrostatic Pressure 20,000 PSI (137.9 MPa)
Operating Voltage 20-29 V
Nominal Current 12 mA
Shock 1,000 g / 0.5 ms
Vibration 25g RMS 30-500 Hz Random

30g 50-300 Hz Sine
Mud Sand Content <1% recommended
Poppet Push Force >100 lbs