Well logging

Claim 1

A WELL LOGGING SYSTEM COMPRISING AN ELONGATED EXPLORING UNIT ADAPTED TO BE PASSED THROUGH THE BORE OF A WELL, MEANS FOR GENERATING AN ELECTRICAL PULSE AT A CONSTANT REPETITION RATE, A FIRST ONE-SHOT MULTIVIBRATOR RESPONSIVE TO SAID ELECTRIC PULSE FOR PRODUCING A SQUARE WAVE, A FIRST DIFFERENTIATOR COUPLED TO THE OUTPUT OF SAID FIRST ONE-SHOT MULTIVIBRATOR FOR PRODUCING A FIRST PULSE AT THE LEADING EDGE OF SAID SQUARE WAVE AND A SECOND PULSE AT THE TRAILING EDGE OF SAID SQUARE WAVE, MEANS RESPONSIVE TO THE FIRST PULSE FROM SAID FIRST DIFFERENTIATOR FOR TRANSMITTING AN ACOUSTIC PULSE THROUGH A SUBSURFACE FORMATION TRAVERSED BY THE WELL BORE BETWEEN TWO SPACED APART POINTS ON SAID UNIT, THE REPETITION RATE OF SAID ELECTRIC PULSE BEING SUCH THAT THE TIME INTERVAL BETWEEN SUCCESSIVE ELECTRIC PULSES REPRESENTING THE TIME OF A CYCLE OF OPERATION IS AT LEAST SEVERAL TIMES LONGER THAN THE EXPECTED LONGEST TIME INTERVAL REQUIRED FOR THE ACOUSTIC PULSE TO TRAVEL BETWEEN SAID TWO POINTS THROUGH THE SUBSURFACE FORMATION, MEANS FOR PRODUCING SIGNALS IN THE EXPLORING UNIT INDICATIVE OF THE VELOCITY OF SAID ACOUSTIC PULSE IN THE FORMATION BETWEEN SAID TWO POINTS, A SINGLE TRANSMISSION LINE, MEANS FOR APPLYING SAID VELOCITY SIGNALS TO ONE END OF SAID SINGLE TRANSMISSION LINE, MEANS FOR PRODUCING SIGNALS IN SAID EXPLORING UNIT INDICATIVE OF THE WELL BORE DIAMETER, A FIRST GATE DISPOSED BETWEEN SAID BOREHOLE DIAMETER SIGNAL PRODUCING MEANS AND THE ONE END OF SAID SINGLE TRANSMISSION LINE, A SECOND ONE-SHOT MULTIVIBRATOR RESPONSIVE TO THE SECOND PULSE FROM SAID FIRST DIFFERENTIATOR FOR PRODUCING A SQUARE WAVE AT THE OUTPUT THEREOF TO OPEN SAID FIRST GATE, THE TIME INTERVALS OF EACH OF THE SQUARE WAVES PRODUCED BY SAID FIRST AND SECOND ONE-SHOT MULTIVIBRATORS BEING A SMALL PORTION OF THE CYCLE OF