Lithology and logging identification of the Carboniferous volcanic rocks in the Chunfeng Oil Field, Xinjiang

The volcanic rocks with different lithological characteristics are quite different in reservoir quality. The identification of volcanic rock types is thus critical for the study of volcanic reservoirs. The Carboniferous volcanic rocks in the Chunfeng Oil Field, Xinjiang vary in rock types and transitional types, and may be classified, with the aid of core observation, thin section examination and geochemical data, into two types:volcanic lavas and volcaniclastic rocks. The former consist of basalt, andesitic basalt, basaltic andesite and andesite, whereas the latter contain tuff and volcanic breccias. The cross plots and star charts are developed in the present paper to study the logging responses of volcanic rocks and the identification of volcanic rock types according to identified lithological calibration and well logs.