The Reservoir Evaluation Of The Chang-2Member Of Theyanchang Formation In Hezhuang Area Of Nanqu Oil Field

Hezhuang area of Nanqu oil field is located in Yan’an city of shanxi province.It’s tectonic location is the Yishan slope of the east Ordos Basin. The Chang-2member of the Yanchang formation is the main bed producing oil.According to characters of lithology, electricity and oiliness,the Chang-2member of the Yanchang formation is subdivided into Chang-21、Chang-22、Chang-23types, and established the unified strati graphic framework on the basis of contrasting the stratigraphic.The structure of Chang-21member of the Yanchang formation is a gently west-dipped monocline, and developing small nose-like structures.Based on the analysis of the facies signs, such as sedimentary background, the distribution pattern of the sandstone in plane, the facies marks and the logging curve, the analysis of the facies shows that the Chang-2member of the Yanchang formation of Hezhuang is a delta plain sedimentary system. And further analysises the type of sedimentary micro facies and the sand distribution pattern of each sub-bed in Chang-21member of Yanchang formation.Based on all the research of flakes, core and sample tests show that the reservoir sandstone of Chang-21member of the Yanchang formation in Hezhuang mainly is feldspar sandstone and Corrosion intergranular pore、intergranular pore. The reservoir sandstone has reached the middle diagenesis B period in the study area. Chang-21member of the Yanchang formtion is the reservoir with especially low pore and especially low permeability and primary is type Ⅱ a and type Ⅲb. And the research shows that the distribution of reservoir is bad and the unhomogenenity is strong.