METHOD OF ELECTRICAL LOGGING OF CASED WELLS Russian patent published in 2010 - IPC G01V3/20 

FIELD: mining.

SUBSTANCE: there used is multipole sonde performed in a form of consecutive and equally spaced measurement units arranged along well axis that consist of three measuring electrodes. There are two current electrodes installed symmetrically to sonde centre beyond measuring electrodes. Sonde current electrodes by turns generate bipolar rectangular pulses of direct current. There performed is measurement and digitisation of electrical potential and its first differentials. All digitised signal quanta are correspondingly processed, filtered and on their basis in every measurement unit there defined is electrical resistivity of rock beds surrounding the cased columns in several points along the well axis.

EFFECT: increase of recording speed, reduction of interferences, increase of differential-input range.

2 dwg