Research On Chang 6 Reservoir Characteristics In Southern Yn Of Ordos Basin

This article is guided by disciplines such as sedimentary petrology,and reservoir geology.Through a variety of analysis and testing methods such as core observation,grain size analysis,thin body casting,scanning electron microscopy,digital logging,and mercury injection experiments,A systematic study of sedimentary characteristics,petrological characteristics,diagenesis,pore structure and reservoir heterogeneity in the study area shows that:The Chang 61 and Chang 62 reservoirs in the Yanchang Formation in the study area belong to the lake delta sedimentary system.They mainly develop delta front subfacies and include various sedimentary microfacies such as underwater diverted channels,estuaries,and diverted bays.Gray-white fine-grained debris feldspar sandstone and fine-grained feldspar sandstone are the main types;reservoir pore space types are mainly composed of intergranular pores,intragranular pores,and feldspar dissolved pores;the main diagenesis of sediments during the burial diagenesis process There are: compaction and compaction,cementation and dissolution.Among them,compaction and compaction and cementation are the main reasons for the compactness of reservoirs in the study area.A large amount of dissolved pores generated by dissolution affect the communication of pore space and improve reservoir storage.Set performance has a positive effect.According to comprehensive analysis of vitrinite reflectance,rock mineral development,inter-particle contact relationship,and reservoir pore type,it is concluded that the reservoirs in the study area reached the middle-diagenetic stage A,and some entered the middle-diagenetic stage B.Reservoir macroscopic heterogeneity is developed through three aspects of in-layer heterogeneity parameters(progression coefficient,variation coefficient,range,etc.),inter-layer heterogeneity parameters(layering coefficient and sandstone density),and planar heterogeneity.Qualitative research,and analyzed and explained that sedimentary facies and diagenesis are the main factors affecting reservoir heterogeneity;comprehensive sedimentary facies,sand body distribution characteristics,pore structure,physical properties,and reservoir heterogeneity In terms of influencing factors,reservoir evaluation criteria for the study area were established,and favorable reservoir distribution areas in the study area were selected.