This is a log of measurements along a well bore (a well-log). You could find this abbreviation
P16H in your log evaluation software or any (ASCII) log files provided by the logging company. The official name for this log is
'ARC Phase Shift Resistivity 16 inch Spacing at 2 MHz, Environmentally Corrected'. The usage of this log is well established. This log helps to evaluate the formation resistivity as measured by the phase shift of a high frequency electromagnetic wave (hundreds of KHz to several MHz, 1.1 GHz in the case of Schlumberger's EPT tool); these measurements are typically sharp (good vertical resolution) and have good dynamic range, but their depth of investigation is less than that of measurements based on attenuation.
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: