Patent ID: 6543280
Filing Date: 2003-04-08
Classification: E21B,G01V

Abstract:
A probe for traversing a borehole having a plurality of benchmarks located therein at known depths, the probe comprising at least one pressure vessel having a depth reference point and depth determining devices associated with the vessel for enabling determination of depth data corresponding to the instantaneous depth of the depth reference point of the pressure vessel, comprising a clock, computer memory for storing depth information corresponding to the depths of the benchmarks, a first sensor for sensing the benchmarks within the borehole relative to the depth reference point of the pressure vessel and generating output data corresponding to the identity of the sensed benchmarks, a comparator for comparing the sensed benchmark identification data to the stored depth information to match the sensed benchmark identification data to corresponding benchmark depths and generate signals corresponding to the depth data of the depth reference point of the pressure vessel at the time of passage of the depth reference point of the pressure vessel, a second sensor for sensing displacement of the depth reference point of the pressure vessel relative to each benchmark and generating output data corresponding to the displacement of the depth reference point of the pressure vessel relative to the most recently sensed benchmark, and an analyzer for analyzing the depth data of the most recently sensed benchmark and the output data corresponding to the displacement of the reference point of the pressure vessel relative to the most recently sensed benchmark to yield data corresponding to the instantaneous depth of the depth reference point of the pressure vessel.