The Research Of Reservoir Characteristics Of The Chang-2 Member Of The Yanchang Formation In Hezhuang Eara Of Yanchang Oil Field

By using the theory and methods of Petroleum Sedimentology, reservoir geology, mineralogy petrology, and reservoir evaluation,a deep study on formation, structure, Sedimentary Characteristics, physical properties characteristics, petrology,diagenesis, heterogeneous characteristics and comprehensive evaluation of Hezhuang erea in Ordos Basin is carried out. Some related results are obtained.Hezhuang erea is located in the territory of Baota District of Yanan City, It is in the middle of the Yishan slope of the Ordos Basin, The main reservoir in the study area is the Chang-2 member of Yanchang formation,which is subdivided into Chang-21、Chang-22、Chang-23 types.The top zone of the Chang-2 member of Yanchang formation understood by Nanniwan Oil Production Plant at present is divided into the Chang-1 member.Therefore, The Chang-1 and Chang-2 Member of Yanchang Formation can be merged as the target layer series,their tectonic framework is established on this basis, showing that the tectonic setting of the study area is a gently west-diped monoclinic,developing small nose-like structures.The Chang-2 Oil Reservoir found in the study area are located in the nose uplift development area.Through the study of regional geological background and various sedimentary facies marks, identifying that Sedimentary models include meandering river and braided river are developed in the target layer of the study area. sandstone thickness maps and Sedimentary Facies Maps with rate of sand tostratigraphy maps as the background.are drawn for analyzing the the Sedimentary microfacies and distribution of sand bodies of the reservoir.The Chang-2 Member of Yanchang Formation is the main oil layer, According to the core observation and thin section examination, lithology is mainly Fine Particle arkose sandstone, At present the Reservoir has reached stage A of the middle diagenetic phase, the main pore type are dissolved pores between grains and intergranular pore.It is the reservoir with low porosity and the extremly low permeability,and the macroscopic heterogeneity is strong,the reservoir is devided into type Ⅲb、type Ⅳa、typeⅣb and typeⅤ.