The Reservoir Evaluation Of The Chang-2 Member Of The Yanchang Formation In Laocaowan Area Of Zichang Oil Field

Laocaowan area of Zichang oil field is located in Zichang county of shanxi province. It's tectonic location is the Shanbei slope of the east Ordos Basin. The Chang-2 member of the Yanchang formation is the main bed producing oil. According to the characters of lithology, electricity and oiliness, the Chang-2 member of the Yanchang formation is subdivided into Chang-21-1. Chang -21-2,Chang -21-3 and Chang-22 types, and established the unified stratigraphic framework on the basis of contrasting the stratigraphic.The structure of Chang -21 member 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-2 member of the Yanchang formation of Laocaowan 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-21 member of the Yanchang formation.Based on all the research of flakes, core and sample tests show that the reservoir sandstone of Chang-2 member of the Yanchang formation in Laocaowan mainly is feldspar sandstone and intergranular pore.The reservoir sandstone has reached the late diagenesis A period in the study area. Chang-2 member of the Yanchang formation is the reservoir with low pore and low permeability and primary is typeâ…¡and typeâ…¢.And the research shows that the distribution of reservoir is bad and the unhomogenenity is strong.Based on the analysis of cluster which with mass parameters, four types of reservoir flow units in the study area were identified, furthermore,the relationship among lithological, reservoir properties, pore structural features, sedimentary microfacies and oil remaining distribution are discussed.