| 摘要 |
<p>For use with a wireline supporting a tool in a well borehole, length measuring apparatus is disclosed. In the preferred form, the length measuring apparatus comprises a housing around the wireline locus, rollers clamping the wireline, and helix following wheels. The wheels track the helix of the wireline around the wireline, rotating on a bearing assembly, and driving a chain. The chain drives an encoder to record length of the wireline in the well borehole.</p> |
