Abstract: The formation and distribution of Chang 2 accumulations in Yanchang Formation in the North Shanxi Slope are considered to be controlled by sedimentary facies and high quality reservoir.Other geological factors such as structure and fracture have a relatively weak effect on the formation of reservoir.The present study shows that the formation and enrichment of Chang 2 reservoir are subject to multiple factors such as:sedimentary facies,high quality reservoirs,the background of noseshaped uplift，regional seal,local seal and migration pathway etc in Panlong Oilfield,among which the nose shaped uplift and local cap rocks are the most important conditions for the formation and enrichment of Chang 2 reservoir because the periclinal structure of nose shaped uplift is rich in hydrocarbon reservoirs and the local cap rocks expand the longitudinal distribution range of oil.Besides lithologic accumulations,structure lithologic composite accumulations are the main types of the Chang 2 accumulations．

Key words: Ordos Basin, Panlong Oilfield, Chang 2 reservoirs, distribution law