Acoustic bore hole logging systems and apparatus

Claim 1

A SYSTEM FOR MEASURING THE ACOUSTIC VELOCITY OF EARTH FORMATIONS ADJACENT A BOREHOLE, WHICH COMPRISES A DOWNHOLE INSTRUMENT MOVABLY POSITIONED IN SAID BOREHOLE AND INCLUDING AN ACOUSTIC PULSE TRANSMITTER MEANS GENERATING AND TRANSMITTING TO SAID FORMATIONS A TRAIN OF ACOUSTIC PULSES AND CONCURRENTLY GENERATING A TRAIN OF SYNCHRONIZING PULSES, SAID DOWNHOLE INSTRUMENT FURTHER INCLUDING A PLURALITY OF ACOUSTIC ENERGY RECEIVERS IN FIXED POSITIONS SPACED LONGITUDINALLY OF THE BOREHOLE FROM SAID TRANSMITTER MEANS, EQUIPMENT ABOVE GROUND INCLUDING MEASURING MEANS MAKING ACOUSTIC VELOCITY MEASUREMENTS RESPONSIVE TO SIGNAL OUTPUTS OF SAID RECEIVERS, SAID MEASURING MEANS INCLUDING A PLURALITY OF INPUT CIRCUITS, CONDUCTOR MEANS PROVIDING AT LEAST ONE CONDUCTOR PAIR EXTENDING THROUGH THE BOREHOLE AND CONNECTING SAID DOWNHOLE INSTRUMENT TO SAID ABOVE GROUND EQUIPMENT, SAID EQUIPMENT INCLUDING SWITCH MEANS ABOVE GROUND CONNECTING SAID CONDUCTOR PAIR IN SUCCESSIVE SEQUENCE TO SAID INPUT CIRCUITS OF SAID MEASURING MEANS, SWITCH MEANS IN THE DOWNHOLE INSTRUMENT RESPONSIVE TO SAID SYNCHRONIZING PULSES AND INDEPENDENT OF SAID ABOVE GROUND EQUIPMENT CONNECTING SAID RECEIVER OUTPUTS IN SUCCESSIVE SEQUENCE TO SAID CONDUCTOR PAIR FOR TRANSMISSION TO THE RESPECTIVE INPUT CIRCUITS OF SAID MEASURING MEANS, AND MEANS FOR DELAYING THE OPERATION OF SAID DOWNHOLE SWITCH MEANS FOLLOWING EACH SYNCHRONIZING PULSE FOR A PERIOD OF TIME SUFFICIENT TO PERMIT THE MEASURING MEANS TO MEASURE THE OUTPUT OF THE RECEIVER CONNECTED TO SAID CONDUCTOR PAIR AT THE INSTANT OF GENERATION OF THE SYNCHRONIZING PULSE.

Claim 2

A SYSTEM FOR MEASURING THE ACOUSTIC VELOCITY OF EARTH FORMATIONS ADJACENT A BOREHOLE, WHICH COMPRISES A DOWNHOLE INSTRUMENT MOVABLY POSITIONED IN SAID BOREHOLE AND INCLUDING AN ACOUSTIC PULSE TRANSMITTER MEANS GENERATING AND TRANSMITTING TO SAID FORMATIONS A TRAIN OF ACOUSTIC PULSES AND CONCURRENTLY GENERATING A TRAIN OF SYNCHRONIZING PULSES, SAID DOWNHOLE INSTRUMENT FURTHER INCLUDING A PLURALITY OF ACOUSTIC ENERGY RECEIVERS IN FIXED POSITIONS SPACED LONGITUDINALLY OF THE BOREHOLE FROM SAID TRANSMITTER MEANS, EQUIPMENT ABOVE GROUND INCLUDING MEASURING MEANS MAKING ACOUSTIC VELOCITY MEASUREMENTS RESPONSIVE TO SIGNAL OUTPUTS OF SAID RECEIVERS, SAID MEASURING MEANS INCLUDING A PLURALITY OF INPUT CIRCUITS, CONDUCTOR MEANS PROVIDING AT LEAST ONE CONDUCTOR PAIR EXTENDING THROUGH THE BOREHOLE AND CONNECTING SAID DOWNHOLE INSTRUMENT TO SAID ABOVE GROUND EQUIPMENT, SAID EQUIPMENT INCLUDING SWITCH MEANS ABOVE GROUND CONNECTING SAID CONDUCTOR PAIR IN SUCCESSIVE SEQUENCE TO SAID INPUT CIRCUITS OF SAID MEASURING MEANS, SWITCH MEANS IN THE DOWNHOLE INSTRUMENT RESPONSIVE TO SAID SYNCHRONIZING PULSES AND INDEPENDENT OF SAID ABOVE GROUND EQUIPMENT CONNECTING SAID RECEIVER OUTPUTS IN SUCCESSIVE SEQUENCE TO SAID CONDUCTOR PAIR FOR TRANSMISSION TO THE RESPECTIVE INPUT CIRCUITS OF SAID MEASURING MEANS, AND MEANS FOR DELAYING THE OPERATION OF SAID DOWNHOLE SWITCH MEANS FOLLOWING EACH SYNCHRONIZING PULSE FOR A PERIOD OF TIME SUFFICIENT TO PERMIT THE MEASURING MEANS TO MEASURE THE OUTPUT OF THE RECEIVER CONNECTED TO SAID CONDUCTOR PAIR AT THE INSTANT OF GENERATION OF THE SYNCHRONIZING PULSE.