The Caliper is a mechanical measurement of the borehole, or casing diameter, using three arms that pivot on a single shaft, providing a measure of minimum diameter. In an open hole, the Caliper helps determine “squeezing” and “wash-out” due to swelling clays, flowing sands, or friable sands. With other open-hole logs, the Caliper is helpful for correlation and understanding log response. Our 3-arm Caliper tool measures borehole or casing diameters from 3″ to 50″.
The log provides a graphic representation of the effective diameter of the borehole as well as total and annular volumes for gravel and cement volume calculations. Annular volume can be calculated for any configuration of casing schedule with varying strings of pipe sizes and lengths. Volumes are presented as a tabular list corresponding with depth and casing schedule (see below).