Microwave device for testing formations surrounding a borehole having means for measuring the standing wave ratio of energy incident to and reflected from the formations

Claim 1

IN COMBINATION, A CAPSULE ADAPTED TO BE POSITIONED WITHIN A WELL BORE; A BACKWARD WAVE OSCILLATOR MOUNTED WITHIN SAID CAPSULE FOR GENERATING HIGH FREQUENCY ENERGY; MEANS CONNECTED TO SAID BACKWARD WAVE OSCILLATOR FOR SUPPLYING EXCITATION VOLTAGES TO SAID BACKWARD WAVE OSCILLATOR; MEANS COUPLED TO SAID BACKWARD WAVE OSCILLATOR FOR RADIATING SAID HIGH FREQUENCY ENERGY FROM SAID WELL BORE INTO A SUB-SURFACE PETROLEUM FORMATION; A BIDIRECTIONAL COUPLER BEING MOUNTED WITHIN SAID CAPSULE AND HAVING A FIRST TERMINAL CONNECTED TO SAID BACKWARD WAVE OSCILLATOR AND A SECOND TERMINAL CONNECTED TO SAID RADIATING MEANS, SAID BIDIRECTIONAL COUPLER HAVING FIRST MEANS FOR OBTAINING A FIRST SIGNAL PROPORTIONAL TO THE HIGH FREQUENCY ENERGY INCIDENT ON SAID SUB-SURFACE FORMATION AND SECOND MEANS FOR OBTAINING A SECOND SIGNAL PROPORTIONAL TO THE HIGH FREQUENCY ENERGY REFLECTED FROM SAID SUBSURFACE FORMATION; INDICATING MEANS POSITIONED AT THE SURFACE OF SAID WELL BORE AND RESPONSIVE TO SAID FIRST AND SECOND SIGNALS FOR MEASURING THE VOLTAGE STANDING WAVE RATIO OF SAID INCIDENT AND REFLECTED ENERGY.