This is a well log used in the oil and gas industry. You might have encountered this acronym
TCMR_MW in your log evaluation software or any (ASCII) log files provided by the logging company. The abreviatin stands for
'Total CMR Porosity - Multi Wait'. Usage of this log is not high and encountering it is a rare occasion. This log displays readings of the apparent formation porosity as measured with an nuclear magnetic logging device. At a more general level these values are measures of the apparent porosity. This is a measure of the initial estimate of porosity, normally from logs, not corrected for the (often large) effects of clays, gas, etc. Such estimates should only be used for qualitative interpretation of clean, gas-free intervals.
In general this log thus reflects units of the volume fraction. Better said, the ratio of the volumes occupied by two components, or by one component to the total volume of the system.This log usually has the unit
'Porosity'. This is the pore volume per unit gross volume. Porosity is determined from measurements on cores or interpreted from logs.
Data for this log is produced by a tool that uses a nmr logging technique and can be used to investigate the porosity of the formation. Similar logs are listed below: