COMPENSATED ELECTROMAGNETIC LOGGING DEVICE DURING SLIM HOLE DRILLING Russian patent published in 2010 - IPC G01V3/30 

FIELD: physics; geophysics.

SUBSTANCE: invention relates to geophysical survey in slim hole wells and geonavigation during drilling. The device has a metal pipe on which there are at least two receiving and two transmitting antenna units. Each antenna unit has cavities on the outer surface of the metal pipe for placing a collet consisting of two identical parts. On each part of the collet there are narrow through longitudinal slots. On the inner surface of each part of the collet there is a triangular ring shaped cavity. At the centre of the cavity on the inner surface of the metal pipe there is triangular ring-shaped cavity. In the cavity on the outer surface of the metal pipe there are narrow longitudinal slots in which there are ferrite inserts. At the centre of the antenna channel formed by triangular ring shaped cavities, there is an antenna wire which is insulated from the metal pipe and centred in the antenna channel by a ceramic layer deposited on the surface using a plasma technique. The antenna wire is connected through sealed leads to a resonance capacitor lying inside the metal pipe.

EFFECT: interchangeability of antenna units, increased reliability and mechanical strength.

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