Definition - What does Wireline Log mean?
Wireline Log is used for regular analysis of the formation properties of electrically powered instruments so as to assume the properties and make relevant decisions about production and drilling operations. The measurement of the properties include passive and active nuclear calculations, sonic properties, electrical properties, formation pressure calculations, formation fluid samples, dimensional analysis of a wellbore, etc. When using the logging tool, long cables are required to be dropped into the wellbore to get continuous feedback and measurements such as density and electrical conductivity.
Petropedia explains Wireline Log
In Wireline logging, a logging tool is dropped into an open borehole on a multiple conductor and contra helically protected Wireline cable. The tool-string is allowed to reach the bottom and then the measurements are taken on the way back from the wellbore. Due to the use of this tool one can get regular feedback from the wellbore and also measurements of various properties.
It is used to get the profile of a formation that is to be drilled and the collected data can be used as a part of an operation of deciding when the drilling should be stopped. The logs are useful to geologists as they help them make relevant decisions related to their study.