WELL BORE PROBE AND METHOD

摘要

1510694 Boring earth &c HOMCO INTERNATIONAL INC 29 April 1975 [29 April 1974] 41701/77 Divided out of 1510693 Heading E1F Apparatus for locating the position 10 (Fig. 1) where a drill pipe P is stuck in a bore hole B comprises a sensor S lowered by a wire W into the pipe P as part of a string of units including a detonator D. When the sensor S is located at the pipe sticking point a tension is applied to the wire W, operating a release mechanism for the sensor to measure relative movement between two parts of the pipe, indicating at surface equipment M that the lower section is stuck. Increasing the tension on wire W operates change over switch contacts 78, 80 enabling a current from control circuit C to be fed via switch K through wire W to a transformer 84 where the current is stepped up sufficiently to ignite the detonator D and release the pipe P.