This is a well log used in the oil and gas industry. The acronym A22H_UNC
is a unique identifier to recognize this particular log and can be encountered in your log evaluation software or your corporate datastores. The official name for this log is 'ARC Uncorrected Attenuation Resistivity for 22 inch Spacing at 2 MHz'
. This log is not used too often in the industry. This log helps 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.
Furthermore, this can be explained by looking at the electromagnetic propagation resistivity. This is a measure of 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: