Control factors of Chang 4+5 reservoir characteristics in Baihe area,Ordos Basin

Reservoir of Chang 4 + 5 is composed of Chang 4 + 52 and Chang 4 + 51 sublayers,is an important oil reservoir in Baihe area in Ordos Basin. Make clear control factors and the reservoir characteristics have great significances. Based on petrological and physical features,study characteristics of Chang4 + 5 oil reservoir set,evaluated reservoir properties and reservoir heterogeneity. Result shows that the reservoir sandstone is compose of light grey oily fine-grained arkose,fine-grain arkose and grain arkose;the pore types are mainly intergranular pores,dissolved pores and microfracture,indicates that Chang 4+ 5 oil reservoir belongs to low porosity,low permeability reservoir. Sedimentation and diagenesis are the main factors. Sedimentation controlled the distribution of reservoir. Compaction and cementation decreased the primary pores,dissolution has positive effects on pore construction. Based on lithology and physical properties,the reservoir is heterogeneity in the space,and the Chang 4 + 52 reservoir performance is significantly better than Chang 4 + 51.