南堡凹陷5号构造沙河街组地层埋藏深度较大，由火山岩与沉积岩构成地层骨架。火山岩的岩性、成份、构造复杂，取心资料、薄片坚定资料及元素测井资料较少，很难满足对全区火山岩分布的认识。首先利用取心井段、薄片鉴定及可靠的录井资料研究层段的火山岩岩性类型，运用交会图将沉积岩与火山岩区分开；再利用M-N交会图对具有不同结构和构造的同类岩性进行识别；然后借助于岩心、薄片、交会图及M-N交会的识别成果作为训练样本，依据单井测井资料的丰富程度，分别建立了10参数、9参数、8参数和6参数识别方程。这一识别方法总体符合率达80%以上，反应了该方法在该地区是适合的。

The Shahejie Formation of the 5th structure in Napu sag is buried deeply. Its stratigraphic skeleton is composed of volcanic and sedimentary rocks. It is hard to recognize the distribution of volcanic lithology owing to its complexity and the lack of core data, thin slice data and elements logging data. This paper firstly uses core data, thin slice and reliable logging data for the research of volcanic lithologic types, used cross plots to separate sedimentary rocks from volcanic rocks, then used the MN cross plot to separate the same type of volcanic lithologic rocks apart which are with different architecture and structure. The results of core data, slices, cross plots and MN cross plots were used as training samples, and equations of 10 parameters, 9 parameters, 8 parameters and 6 parameters were established. The coincidence rate attains over 80%, which shows that the dentification method is feasible in the study area.