METHOD OF INDUCTIVE LOGGING FROM CASED WELLS AND DEVICE FOR ITS IMPLEMENTATION Russian patent published in 2017 - IPC G01V3/28 

FIELD: oil and gas industry.

SUBSTANCE: low-frequency electromagnetic field is excited in the environment with the help of harmonic currents in the system of two coaxial transmitter coils with opposing moments of different sizes conveyed within the well studied, and host rock electrical resistance value is determined. Location of the system of two transmitting coils and their moments are chosen so that the measured current -antiphase squaring of the magnetic induction (JmBz) axial component, created by the current in the transmitting coils, placed in a conductive casing string in non-conductive medium, was compensated (close to zero). If the host medium is conductive (rocks), the JmBz component of the magnetic induction will be uncompensated (different from zero) by the induction field in the conducting medium. The magnitude and frequency of the JmBz component behavior determine the value of the host rock electrical resistance.

EFFECT: improved accuracy of medium resistance determination in the cased well annulus during geophysical studies.

2 cl, 4 dwg