Igneous reservoirs are characterized by diversity of eruption patterns and lithology geneses

and variation in mineralogy assemblage.It is really difficult to identify lithology in details

which in turn will greatly hinder the correct calculation of reservoir parameters

as well as subsequent hydrocarbon development strategies.Therefore

the study took a case study of the carboniferous igneous reservoirs in Chunfeng oilfield

Junggar Basin.The lithological categories of the reservoirs are basalt

basaltic andesite

andesite

tuff and volcanic breccias.A combination of core

thin section and other tests' data were used in the study.Then the logging response characteristics of different lithologies were clarified.The tuff and volcanic breccia were identified with the cross plot technique and "progressive stripping" concept.For the hard-to-identify volcanic lava

we used the empirical mode decomposition algorithm to convert the conventional logging data into multiple band sets of intrinsic mode functions

and attained the energy entropy of empirical mode function of various logging parameters for lavas.Then the precise identification of igneous lithologies was realized by using the discriminant algorithm.In applying the method to the block

we found that the overall matching rate of the proposed method is 93.7%

which has greatly improved the accuracy of lithological identification.