Ultra-slim Focussed Induction Probe

A new addition to the RG Ultra-slim probe range, the 25mm focussed induction is designed for boreholes or plastic casings down to 30mm ID. Despite its small size, the probe offers excellent standards of range and repeatability with low thermal drift. The ultra-slim focussed induction probe produces accurate formation conductivity logs even in dry or plastic-lined boreholes. The probe coil spacings are optimised to achieve high vertical resolution and a deep radius of investigation, with minimal borehole influence when logging in conductive-fluid-filled holes.

PRINCIPLE OF MEASUREMENT
An oscillating high-frequency magnetic field from a transmitter coil in the probe induces an alternating electrical current within the surrounding formation proportional to its electrical conductivity. This current, in turn, induces voltages within the receiver coils. These are phase discriminated and measured. These voltages are proportional to the formation conductivity. Additional focussing coils minimise the contribution of the borehole signal.