LOGGING-WHILE-DRILLING USING A DIRECTIONAL SONDE

摘要

A directional instrument for measuring the electrical conductivity of earth formations which may be employed during the drilling of a borehole includes an array of coils set into a pocket in a support element (for example a drill collar) and electronics for processing the measurement into a form suitable for data storage and/or for transmission to surface by known means. The measurement is of the type known as an induction measurement, employing relatively low frequency (10kHz to 200kHz) alternating magnetic fields. The radial response of the measurement can provide information about the radial distribution of formation conductivity, thus facilitating geosteering.