Reservoir Characteristics And Accumulation Of Oil And Gas For Fuxian Formation In Jihuang 32-Xiaojianzi Block,Ordos Basin

Jihuang 32-Xiaojianzi Block is located in the central and eastern part of Ordos Basin,covering an area of about 234.4km~2.With the development of Fuxian Formation oil reservoirs,the production of single well decreases and water cut increases,the reserve succession of Fuxian Formation becomes a major problem.Taking this problem as the center,the logging data of 501Wells in the study area and the core thin section data of adjacent areas are used to focus on the study of reservoir characteristics and hydrocarbon accumulation.The achievements are as follows:The optimal segmentation method is used to accurately identify the unconformable surface at the bottom of Fuxian Formation,and an accurate sequence stratigraphic framework is established.On this basis,the sedimentary palaeogeomorphology of Fuxian Formation was recovered by imprint method,which can be divided into three geomorphic units:highland,slope and valley.On the basis of provenance analysis,comprehensive analysis of core and well logging,combined with the characteristics of sand body thickness and sand-to-ground ratio distribution of the Fuxian Formation,it is determined that the Fuxian Formation belongs to restricted fluvial facies,and there are three microfacies including channel filling,channel margin and flood plain.Through the analysis of core and well logging data,reservoir rock types in order to clear the rich county group of lithic arkose,pore types are mainly intergranular pore and dissolution pore,diagenesis mainly compaction and dissolution,four relationships,combined with reservoir microfacies and reservoir property model,determine the rich county group of channel lateral microfacies is favorable reservoir distribution zone.Combined with previous studies and the profile characteristics of Fuxian reservoir,it is clear that the main controlling factors of Fuxian reservoir composition are palaeogeomorphologic slope and small nose structure.According to the relationship between structure and reservoir physical properties and the disposition of sedimentary microfacies,three favorable exploration and development targets are selected.