Abstract: The pyrolith reservoir of Honghaoershute sag in Erlian Basin is an important exploration area, where the andesite widely distributed in the third member of Aershan Formation is the main target strata, and it is one of the exploration difficulties to predict the distribution of the pyrolith reservoir effectively. Aiming at the andesite reservoir characteristics and prediction difficulties, the authors predict the spatial distribution patterns and the thickness change of andesite with some measures such as natural gamma analog acoustic wave inversion, natural gamma reservoir parameter inversion, seismic attributes and so on. According to the characteristics of andesite lithofacies, synthesizing the fracture structure, seismic facies, seismic energy, frequency attenuation attributes, the result of andesite inversion prediction and the strata thickness gotten from drilling, the authors predict the andesite facies. It is believed that the development areas of the fracture and the volcano slopes at a middle distance from the volcano center are favorable reservoirs.

Key words: andesite, seismic inversion, seismic attributes, seismic facies, lithofacies, Honghaoershute sag, Erlian Basin