Characteristic of Mesozoic Volcanic Rock and Analysis of Reservoir Controlling Factors in the Honghaoershute Sag of Erlian Basin

Based on core observation,thin section identification and integration of well log and seismic data of the Honghaoershute Sag,the distribution pattern of Mesozoic volcanic rock in the Honghaoershute Sag of Erlian Basin was distinctly defined.This study proposed that the Mesozoic volcanic rock developed mainly within the Aershan Formation lower segment,Aershan Formation upper segment and Tengger Formation first segment,and consists of andesite,tuff and volcanic breccia.xplosive facies,effusive facies and eruptive sedimentary facies can be identified,with effusive facies well developed and widely distributed.The Mesozoic volcanic rocks are distributed mainly along faults and superimposed by multiple volcanic eruptions.Three cycles and fourteen periods of volcanic eruption have been identified.The reservoir porosity is versatile,and stomata and fractures are predominant.Reservoir accumulation is controlled mainly by petrology,lithofacies and tectonic action as well as diagenesis.