Coupling Relationship Of Diagenesis Evolution And Pore Evolution Of Thin Interbeded Sandstones Reservoirs Of The Upper Es4 In Lijin Sag

With the exploration and development of oil and gas.The deep clastic reservoir exploration has become a hot spot of mature exploration area.The porosity evolution of low porosity and permeability reservoir,especially the coupling relationship between porosity evolution and diagenetic evolution has become one of the central issue.The target horizon of the study is the thin-interbedded sandstone of upper part of the fourth member of the Shahejie Formation in linjin depression.The author recognized petrologic characteristics of target horizon on the base of a large number of domestic and foreign literature research,by analyzing diagenesis study area on the porosity evolution for the study area characteristics of thin interbedded sand using inversion recovery method and stripping back diagenetic fluid physics experiment simulation.The paper analyses the coupling relationship between different diagenesis stages evolution and pore evolution by quantitative and semi-quantitative method.The main research achievements are as follows:Raval out the petrologic feature of thin interbedded sand in study area,through core description,thin section analysis,SEM analysis and X diffraction of whole rock analysis.The clastic grain of target horizon is in different sizes,mainly siltstone and sandstone.The main type of rock is sandstone and feldspar lithic feldspathic sandstone.Roundness is mainly sub-angular to sub-rounded,medium rounding and sorting.Clastic particles are mostly supported by particles,mainly by point contact and line contact.The main types of cementation are porous cement and contact cement.It is defined that different types and characteristics of sandstone and the impact of different diagenesis and diagenesis stages on the change degree of porosity of upper Es4 in the study area.It is defined that different types and characteristics of sandstone and the impact of different diagenesis and diagenesis stages on the change degree of porosity of upper Es4 in the study area.Compaction is the main reason of the densification of sandstone.To a certain extent,cementation has reduced the porosity of sandstone.But the dissolution pore formed by the dissolution increases the total porosity of sandstone.Study area experienced three diagenesis stages determind by mineral diagenesis chang,which can be divided into early diagenesis stages,intermediate diagenesis stage and late diagenesis stage.By the method of restoring paleofluid physical modeling,The experiment shows the evaluation of two main dissolution dagenesis stage,which can be used to restore the effect of resorption and weaken the effect of compaction and cementation.The result of the experiment shows that the acid fluid,rich in HC₂O₃^-?H⁺?Ca²⁺?Cl^-,can dissolve feldspar,kaolinite and detritus;the alkaline solution,rich in HCO₃^-?OH^-?Na⁺?Cl^-,can dissolve ferrocalcite,the pore effect and increase the numerical aperture before diagenetic evolution finds similar,ankerite and quartz.It proved that different minerals will be dissolved in different solution,which plays an important in the effective reservoir forecasting.