This is an acronym for a well log used in the oil and gas industry. The acronym A28H_UNC
can be found in any (ASCII) log files provided by the logging company. ARC Uncorrected Attenuation Resistivity for 28 inch Spacing at 2 MHz
is the full name for this log. This log is not often acquired after (or during) drilling a well. This log can be used to evaluate the formation resistivity as measured by the attenuation of a high frequency (hundreds of KHz to several MHz) electromagnetic wave; these measurements are typically deeper than measurements based on phase shift, but their vertical resolution is less sharp and they often cannot be used reliably in high-resistivity formations.
In general this log thus reflects units of the electromagnetic propagation resistivity. In other words, the formation resistivity as measured by the attenuation or phase shift of a high frequency electromagnetic wave; the frequency range for these measurements is higher than that of induction measurements, typically hundreds of KHz to several MHz, and over 1 GHz in the case of the Schlumberger EPT tool.This log usually has the unit 'Resistivity'
. This is the property of a material which resists the flow of electrical current. The ratio of electric-field intensity to current density. The reciprocal of conductivity.
Data for this log is produced by a tool that uses a electromagnetic logging technique and can be used to investigate the resistivity of the formation. Similar logs are listed below: