METHOD AND APPARATUS FOR LOGGING INCLINED EARTH BOREHOLES USING THE MEASURED ACCELERATION OF THE WELL LOGGING INSTRUMENT

摘要

In the logging of earth boreholes, problems have been encountered when the logging instrument is lowered through a non-vertical section of borehole. The instrument tends to slow-up or stop, and if the pay out of cable continues at a fast rate, the cable will overrun. In the apparatus described the logging instrument 30' includes an accelerometer 47 which is used to obtain an indication of the instrument velocity. This velocity is compared with the cable 32 velocity measured at the earth's surface, and if the two figures differ by sufficient margin the speed of the cable winch 33 is controlled and/or means on the instrument are activated to speed up the descent of the instrument. The means may comprise electromagnetically movable vanes 40 or an ejector for supplying a friction reducing agent to the area around the instrument. IMAGE