WELL BORE DATA-TRANSMISSION APPARATUS WELL BORE DATA-TRANSMISSION APPARATUS

摘要

1436455 Liquid immersed siren; slip clutches; control of A.C. motors SCHLUMBERGER INLAND SERVICES Inc 15 June 1973 [15 June 1972 (3)] 28619/73 Heading G5J [Also in Division H2] To transmit from the bottom of an oil well to the surface sonic tones, frequency or phase modulated to indicate the value of physical variables at the well foot, a siren interrupting the downward flow of drilling mud is driven by a two-phase induction motor, itself supplied variably via a control unit from a mud-driven turbo-generator, all situated at the foot of the well. Mud passes through longitudinal rotor slots 136 alternately aligned with-or-opposed to stator slots 130. If debris locks the rotor while the slots are obstructed, increased pressure differential causes oil from elastomeric bar 153 to force the stator 127 downward against spring 151, allowing debris to clear. Simultaneously, whether the slots are obstructed or not, slippage or torque clutch 41, with three balls 142 in cam recesses 139, 140, causes rotor 133 to move upward, again allowing debris to clear. In other embodiments the rotor, below the stator, is withdrawn by excess differential pressure only (Fig. 2, not shown) or by excess pressure differential and by excess torque by means of helical grooves (Fig. 5, not shown). If the separation of the rotor and stator fails to clear the obstruction, the circuit of Fig. 9 detects the discrepancy between intended and actual speed, and initiates count 262 of supply cycles. When a preset munber is reached, one phase of the motor supply is reversed 225; causing the torque to reverse, at the same time resetting the counter. Alternate torque reversals continue until the debris is cleared and normal working resumes.