Abstract: The lower No.3 section of Hetaoyuan formation of Paleogene in Anpeng oilfield is a major horizon for exploration, its sedimentary facies study is of significant guidances for exploration and development of this field. Based on core lab, well log and geological logging data and analysis of the depositional characteristics, it is believed that the No.3 section of Hetaoyuan formation belongs to a near-source fan deltaic deposit with fan delta front and pro-fan delta subfacies, except for fan delta plain. The fan delta front is furthermore divided into the near-source and the far-source underwater distri butary channels, the mouth bar, the far bar sand, frontal sheet sand and inter-tributary channel. The sedimentary microfacies study reveals its effect on the reservoir quality, confirming the relationship between the microfacies and petroleum distribution. The results show that there exist apparent differences of reservoir quality and petroliferous feature in different sedimenrary facies. The far-source underwater distributary channel and mouth bar are good in reservoir quality, being the main facies for petroleum accumulation; the frontal sheet sand and far bar sand are relatively poor.

Key words: Biyang sag, palecgene, sedimentary characteristic, fan, delta