The heterogeneity characteristics of the Paleozoic tight sandstone reservoirs in Gaoqiao area of Ordos Basin are studied in detail in this paper by using core data

logging data

and test data.The results show that there is a close relationship between heterogeneity and sedimentation of the Shanxi Formation and Xiashihezi Formation sandbodies.The sandbodies formed by vertical accretion show vertical positive rhythm or flanges positive rhythm with no obvious trend.In contrast

those sandbodies formed by lateral accretion show strong vertical positive rhythm.Sandbodies formed by progradation have apparent vertical anti-rhythm.Sandbodies of overland flow deposition display little change or a slight vertical counter-rhythm.He8 and Shanxi Fm reservoirs show strong intralayer heterogeneity.The heterogeneity of Shan2 segment is stronger than that of Shan1

while the heterogeneity of lower He8 segment is stronger than that of upper He8 segment.Among these four sub-layers

the upper He8 segment is most homogeneous.Interlayer heterogeneity significantly varies among different layers.He8 segment and Shanxi Formation also show strong lateral reservoir heterogeneity in Gaoqiao area.