Abstract: Igneous rock reservoir has been important explorative target and potential reserve target.In igneous rock evaluation,identifying fractures and hydrocarbon is a key issue.In view of the factors,i.e.conventional well logging is difficult to identify the complicated mineral components and lithology,the characteristics are used that acoustic energy attenuation is very sensitive to the response of natural fractures and that Schlumberger S wave data can be used to calculate the property of energy attenuation of P wave,S wave and stoneley wave,the effective identification to fractures is realized.Under the conditions of physical property and lithology being basically coincident,by means of S and P wave energy overlap,poisson ratio and wave velocity ratio,the gas formation can be identified,the practical application of Karamay igneous rock reservoirs indicates DSI data plays an important role in igneous rock reservoir evaluation,the method explores a new path for igneous rock fracture and hydrocarbon identification.

Key words: igneous rock reservoir, fracture identification, hydrocarbon identification, DSI, energy attenuation