Abstract: Lithologic identification is fundamental technology in volcanic reservoir research. Fisher discrimination can be used to represent multiple variances differences into several functions, with algorithm stability, massive information, high accuracy and convenient application, so generally applied to volcanic lithologic identification researches. Base on petrologic characters of volcanic rocks of Carboniferous in Hongshanzui oilfield of Junggar basin and investigation on log responses of three sub-types and nine kinds of rocks, this paper establishes the identification model of those rocks with high recognition rate using Fisher discrimination. Application of this result to 46 wells with regular logging data for lithologic identification is made, laying a foundation for evaluation of difficult-recovery reserves of such a volcanic reservoir in this area.

Key words: Hongshanzui oilfield, volcanic rock, lithologic identification, Carboniferous