Wireline Surveying Techniques
Most directional survey tools take surveys at discrete directional survey stations, with manual input of the wireline depth. The standard instrumentation on a wireline unit is the Gearhart Owen wireline speed and length measuring system with a Martin Decker 0-4,550 kg (0-10,000 lbs) weight indicator to measure the cable tension. Typical accuracies are about 0.002 AHD/AHD at best.
The wireline logging companies have more sophisticated measuring heads, usually with tangential wheels and electronic encoders that can provide depth inputs directly into the logging unit computer.
Some . . .