Abstract: By study on the characteristics of reservoir petrology and sedimentology in target strata,the authors first expound that the sedimentary environment of the Sha 3 Member is river shore shallow lake environment,the sedimentary system belongs to lakeshore depositional system,and the sedimentary facies of the reservoir are braided river delta facies.This result has very important directive significance for the rolling development of the field and the evaluation of prospect area.