Abstract: Disclosed is a separated multi-core transmitting device based on a ground transient electromagnetic method, comprising: a rectangular transmitting coil enclosed by a cable I, a cable II, a cable III, and a cable IV. Each of the cable I, the cable II, the cable III, and the cable IV is provided with N wires. Two ends of each of the N wires is provided with a sub connector and a female connector, respectively. The sub connectors and the female connectors are detachably connected through sub connector interfaces and female connector interfaces. A first wire of the female connectors of the cable I is led out to serve as a positive electrode of a transient electromagnetic instrument transmitter, and a last wire of the sub connectors of the cable IV is led out to serve as a negative electrode of the transient electromagnetic instrument transmitter.

Abstract: A time domain electromagnetic tensor based logging method, relating to the field of induction logging. A transmitting coil system Tx and a receiving coil system Rx are each composed of three orthogonal direction coils, and the transmitting coil system and the receiving coil system form a borehole probe; a time domain electromagnetic field is excited by means of two orthogonal transmitting coil systems Tx, and a secondary field signal is received by two orthogonal receiving coil systems Rx located above transmitting coils and having a distance D; during each measurement, three directions are used for transmitting, nine component data is received at the same time, and each component is a series of induction potentials in one-to-one correspondence with measurement time sequences, and a potential or resistance change, from near to far, of the rock stratum where a measurement point is located is obtained after time-depth conversion.

Abstract: A time domain electromagnetic tensor based logging method, relating to the field of induction logging. A transmitting coil system Tx and a receiving coil system Rx are each composed of three orthogonal direction coils, and the transmitting coil system and the receiving coil system form a borehole probe; a time domain electromagnetic field is excited by means of two orthogonal transmitting coil systems Tx, and a secondary field signal is received by two orthogonal receiving coil systems Rx located above transmitting coils and having a distance D; during each measurement, three directions are used for transmitting, nine component data is received at the same time, and each component is a series of induction potentials in one-to-one correspondence with measurement time sequences, and a potential or resistance change, from near to far, of the rock stratum where a measurement point is located is obtained after time-depth conversion.