METHOD AND DEVICE FOR DIAGRAPHY FOR THE STUDY OF GEOMETRIC CHARACTERISTICS OF A DRILLING.

摘要

The invention relates to a method and a logging device for the study of geometric characteristics of a borehole. BR/ A first aspect of the device includes an array of current azimuthal electrodes (Aazi) spaced circumferentially from each other on a probe (21) and a current ring electrode (A) longitudinally spaced from the array of azimuth electrodes. . Currents (Here) are emitted between the azimuthal electrodes and the ring electrode (A). BR/ Control electrodes (M, Mazi) are respectively associated with the current electrodes (A, Aazi). The potential difference (DELTAVci) is detected between the annular control electrode (M) and each azimuthal control electrode (Mazi). In response to the detected potential differences, output signals (Rci) indicative of the distances between the probe and the borehole wall in several directions around the probe are constructed. The invention further relates to the application of such a technique to azimuthal resistivity measurements of geological formations traversed by a borehole with a view to correcting these measurements for the eccentricity of the probe and / or for the irregular shape of the section of the borehole. drilling.