GB1378206A - Automatic drilling break alarm and shutdown system - Google Patents

Abstract

1378206 Monitoring drill bit speed DRESSER INDUSTRIES Inc 8 Aug 1972 [22 Oct 1971] 36888/72 Heading G1N [Also in Division E1] A system for monitoring the rate of penetration (ROP) of a drill bit in drilling, comprises means for monitoring the ROP and for generating a signal functionally related to the ROP, and means responsive to this signal for controlling the drawworks associated with the drill bit when the ROP is higher than a predetermined level. An encoder mechanism 45, Fig. 2, converts rotational movement of a wheel 33, linked by means of a wire 31 to the drill, into electrical pulses and the output of the mechanism is coupled to a conventional filter and buffer section 46 and then to a gate circuit 47. The gate output drives a series of electronic counters 49, 50 and 51 which is coupled to an accumulator 52 which drives a diode matrix and buffer circuit 53 which in turn drives a read-out section 54 and a visual drill depth monitor 41. The gate 47 is also connected to a one shot multi-vibrator 60 the output of which is coupled into a filter 61 to drive an amplifier 62. The amplifier is connected to a voltage discriminator 72, Fig. 3, and AND gates 74, 77, 80 and 81 such that firstly, when the output of amplifier 62 exceeds a certain value (which is indicative of ROP) a first alarm 76 is activated, secondly, when this value is maintained over a predetermined drilling depth interval (this information being received from the counter 51) a second alarm 83 is activated, and ultimately, when the value is maintained over a further predetermined depth interval a drawworks control 84 is activated to cease drilling. Alternatively, circuitry, Fig. 4 (not shown), may be provided in which the second alarm and drawworks control are activated after predetermined intervals of time rather than intervals of depth of drilling.