Array Propagation Resistivity
Definition - What does Array Propagation Resistivity mean?
An Array Propagation Resistivity is a tool that records values by measuring while drilling (MWD). The Array Propagation Resistivity compensated tool consists of an array of receivers and transmitters that receive and transmit signals. The transmitted and received signals are combined by software which provides resistivity logs used to analyze the wellbore properties for target depths of investigation.
Petropedia explains Array Propagation Resistivity
An Array Propagation Resistivity tool typically consists of five transmitters and two receivers as shown in figure below. These transmitters emit a magnetic field at different frequencies which travels through the formation while the receivers continuously measure the change in phase and attenuation of these signals. Multiple depths of investigation are possible by varying the distance between the transmitter and receivers. The phase shifts and attenuation are combined in different ways to produce borehole-compensated logs, which provide resistivity to various strata at different depths.
Various factors influence the measurement of resistivity such as eccentricity, dielectric effects, resolution, bore-hole conductivity and invasion. The main reason for multiple measurements is to determine several parameters simultaneously. In addition to the resistivity measurements, this tool also provides natural gamma ray measurements, annular pressure-while-drilling (APWD) and real-time static pressure.