DIELECTRIC SPECTROSCOPY FOR FILTRATE CONTAMINATION MONITORING DURING FORMATION TESTING

摘要

An apparatus for estimating a volume fraction of a formation fluid in a sample having a filtrate contaminant includes: a carrier configured to be conveyed through a borehole; a downhole fluid extraction device disposed at the carrier and configured to extract a sample of a formation fluid through a wall of the borehole; and a dielectric spectrometer and configured to transmit electromagnetic energy into the extracted sample at a plurality of frequencies and to measure a plurality of responses to determine a permittivity of the extracted sample fluid as a function of frequency. The apparatus further includes a processor configured to receive the permittivity of the extracted sample as a function of frequency from the dielectric spectrometer and to estimate the volume fraction of the formation fluid using a permittivity at a selected frequency in the plurality of frequencies for the sample as measured by the dielectric spectrometer.