摘要
Based on the sedimentary and petroleum geology theory and through the observation of outcrops,cores,and slices and testing analysis, the authors study the Ordovician organic reefs on the west margin of Ordos Basin.The authors reach out a conclusion that the Ordovician organic reefs on the west margin of Ordos Basin are the coral reefs of the Lower Ordovician Zhuozishan Formation located in Wuhai Zhuozishan in the north,the stromatoporoids-sponge reefs of the Lower Ordovician Kelimoli Formation of Well Qitan 1 in the middle and the coral reefs of the Upper Ordovician Beiguoshan Formation in Shijiezigou in the south.