Method and apparatus for making a dipmeter survey of a borehole

Claim 1

IN AN APPARATUS FOR LOGGING A BOREHOLE TO DETERMINE THE DIP OF AT LEAST ONE STRATUM IN THE EARTH FORMATIONS SURROUNDING THE BOREHOLE, THE COMBINATION OF A DOWNHOLE TOOL INCLUDING AT LEAST THREE SPACED APART SENSING ELEMENTS, MEANS BIASING SAID SENSING ELEMENTS INTO ENGAGEMENT WITH THE WALLS OF THE BOREHOLE, MEANS FOR MOVING SAID TOOL THROUGH THE BOREHOLE SO THAT SAID SENSING ELEMENTS PASS ALONG THE WALLS OF THE BOREHOLE, MEANS FOR DEVELOPING FROM EACH SENSING ELEMENT CHARACTERISTIC SIGNALS REPRESENTING AT LEAST ONE CHARACTERISTIC OF THE EARTH FORMATIONS VARYING FROM STRATUM TO STRATUM, CALIPER MEANS IN SAID TOOL RESPONSIVE TO THE MOVEMENT OF AT LEAST ONE OF SAID SENSING ELEMENTS RESULTING FROM CHANGES IN BOREHOLE DIAMETER FOR DEVELOPING CALIPER SIGNALS INDICATIVE OF THE VARIATIONS IN BOREHOLE DIAMETER, AN INCLINOMETER APPARATUS ON SAID TOOL FOR DEVELOPING INCLINOMETER SIGNALS INDICATIVE OF THE DIRECTION AND INCLINATION OF THE BOREHOLE, SAID SENSING ELEMENTS, SAID CALIPER MEANS AND SAID INCLINOMETER APPARATUS BEING MOUNTED IN FIXED, PREORIENTED POSITIONS RELATIVE TO THE TOOL, MEANS FOR DEVELOPING SIGNALS INDICATIVE OF THE AZIMUTH OF THE TOOL DURING ITS MOVEMENT THROUGH THE BOREHOLE INCLUDING A LIGHT SENSITIVE DEVICE, A MOVABLE LIGHT SOURCE, MEANS FOR CLOSING A CIRCUIT WHEN THE LIGHT SOURCE IS ALIGNED WITH A FIXED REFERENCE POINT ON THE TOOL, AND A COMPASS MEMBER MOUNTED FOR ROTATION UPON THE TOOL BETWEEN THE SOURCE AND THE DEVICE FOR CONTROLLING THE PASSAGE OF LIGHT TO THE DEVICE, MEANS FOR DEVELOPING A COMBINED SIGNAL FROM SAID INCLINOMETER SIGNALS AND SAID SIGNALS INDICATIVE OF THE AZIMUTH OF THE TOOL AND MEANS FOR RECORDING SAID CALIPER SIGNALS, SAID CHARACTERISTIC SIGNALS, AND SAID COMBINED SIGNAL.