Abstract: A method for division of reservoir petrophysical facies by fuzzy clustering is proposed. Taking Dagang Zaonan oilfield as an example and selecting the parameters of sedimentation and diagenesis, the five types of petrophysical facies featuring the reservoir rocks in this studied area are given by this method. And the relationship between the petrophysical facies and the production indices of the oilfield is analyzed. The study shows that with upgrade of the petrophysical facies level, both of the reservoir genetic parameters and the statistical petrophysical properties gradually change better, so does related reservoir productivity. The conclusion does help to searching for the favorable oil/gas-enriched horizons and remained oil-gas abundant areas. Also, this is as a guide for further regulation and additional potentials in this oilfield.

Key words: fuzzy clustering, petrophysical facies, reservoir rock, composite evaluation