Description Of Yan9 Reservoir In Y66 Area Of Jing'an Oilfield In Ordos Basin

At present,Yan9 reservoir group has become an important oil production replacement layer in Y66 area of Jing'an oilfield.Due to complex pore structure,low stable production rate,relatively weak reservoir geological research and great development difficulty,fine reservoir description of Yan9 reservoir in the study area can provide theoretical basis for improving oil recovery and formulating reasonable development plan.In this paper,the sedimentary facies,petrology,pore structure,reservoir flow unit and reservoir characteristics of Yan9 are systematically studied by using drilling data,logging data,SEM,thin cast sheet,high pressure mercury pressure,NMR and oil-water permeability experiments.The sedimentary facies,petrology,pore structure,reservoir flow unit and reservoir characteristics of Yan9 are systematically studied.The concept of connecting thickness and connectivity coefficient is introduced to Yan9 Finally,petrographic model,structural model and attribute model can be established to reflect the spatial structure of reservoir by using petrel software and stochastic modeling.The results show that:the Yan9 reservoir in the study area is delta plain subfacies,and develops distributary channel and inter channel microfacies.The channel sandstone is mainly feldspathic sandstone,which mainly develops medium porosity medium fine throat type and small hole fine throat type,and belongs to low porosity low permeability reservoir.The three types of flow units in each small layer of Yan9 are the most developed.The reservoir type in the study area is lithologic structural reservoir with well-developed water layer.Through the analysis of sand body superposition type,it can be concluded that the connectivity of Yan 9₁²and Yan 9₂²sublayers is better,followed by Yan 9₁¹and Yan 9₂¹sublayers,and the connectivity of Yan 9₃¹and Yan 9₃²sublayers is poor.In the lithofacies model,sandstone is developed in distributary channel microfacies,and mudstone is developed in inter channel microfacies,which is consistent with the geological research;the attribute model established under facies controlled conditions has good consistency with the lithofacies distribution.