| 摘要 |
A hydraulic technique for logging well holes particularly in oil mining environments where the well holes extend upwardly from mining drifts. In the technique, the logging tool is initially positioned within the well hole in a fluid-tight, sealing engagement with the well hole. The tool is connected by a flexible cable to conventional logging instruments located in the drift and to raise the tool, fluid under a first pressure is supplied below the tool within the well hole. Once raised to the desired height within the well hole, the cable is drawn downwardly raising the pressure in the fluid below the tool to a second pressure. Through a disclosed arrangement including a back pressure regulator, the pressure below the tool is maintained at the second pressure as the cable continues to be drawn downwardly. The logging tool is preferably operated as the tool is being lowered and the steady back pressure serves to provide a constant force against the downward withdrawal of the cable and tool so that the travel rate of the tool is relatively uniform. Other disclosed details of the invention include procedures and apparatuses for initially positioning the tool within the well hole and details of a fluid circuit which can be used to both raise and lower the tool.
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