Method and device for downhole measurement of depth of borehole

摘要

The process registers borehole depth and comprises the transmission of data into a downhole computer. The data includes length measurements of the tubular drill string (5) sections (3) to be added, together with the initial depth of the borehole (8). This information is stored in the computer, together with data defining the proposed course of the borehole. Before introduction, or on reaching the initial depth, the computer detects the number of drillstring sections added, using a sensor, as the borehole is sunk. This enables a programme in the computer to calculate the depth reached. Also claimed is the corresponding apparatus.