Electric or magnetic prospecting or detecting Measuring magnetic field characteristics of the earth

GPHYSICS G01Measuring instruments G01VGEOPHYSICS GRAVITATIONAL MEASUREMENTS DETECTING MASSES OR OBJECTS

G01V3/00Electric or magnetic prospecting or detecting Measuring magnetic field characteristics of the earth

G01V3/02operating with propagation of electric current G01V3/04using dc G01V3/06using ac G01V3/08operating with magnetic or electric fields produced or modified by objects or geological structures or by detecting devices G01V3/081the magnetic field is produced by the objects or geological structures G01V3/082operating with fields produced by spontaneous potentials G01V3/083Controlled source electromagnetic [CSEM] surveying G01V3/087the earth magnetic field being modified by the objects or geological structures G01V3/088operating with electric fields G01V3/10using induction coils G01V3/101by measuring the impedance of the search coil; by measuring features of a resonant circuit comprising the search coil G01V3/102by measuring amplitude G01V3/104using several coupled or uncoupled coils G01V3/105forming directly coupled primary and secondary coils or loops G01V3/107using compensating coil or loop arrangements G01V3/108the emitter and the receiver coils or loops being uncoupled by positioning them perpendicularly to each other G01V3/12operating with electromagnetic waves G01V3/14operating with electron or nuclear magnetic resonance G01V3/15specially adapted for use during transport G01V3/16specially adapted for use from aircraft G01V3/165operating with magnetic or electric fields produced or modified by the object or by the detecting device G01V3/17operating with electromagnetic waves G01V3/175operating with electron or nuclear magnetic resonance G01V3/18specially adapted for well-logging G01V3/20operating with propagation of electric current G01V3/22using dc G01V3/24using ac G01V3/26operating with magnetic or electric fields produced or modified either by the surrounding earth formation or by the detecting device G01V3/265Operating with fields produced by spontaneous potentials G01V3/28using induction coils G01V3/30operating with electromagnetic waves G01V3/32operating with electron or nuclear magnetic resonance G01V3/34Transmitting data to recording or processing apparatus Recording data G01V3/36Recording data G01V3/38Processing data G01V3/40specially adapted for measuring magnetic field characteristics of the earth