| The distribution characteristics of sedimentary facies are the main controlling factors of hydrocarbon accumulation,the pore-throat structure of the reservoir rock is characterized by the main factors that determine the fluid flow,hydrocarbon migration and hydrocarbon productivity in microscopic pore-throat.Therefore,it is of great significance to study the sedimentary system,sedimentary microfacies characteristics and microscopic pore-throat,and for the future generations to study the region to bring some reference value.This paper takes Chang 8-1 oil layer of Yanchang Formation of Maling Area as research object;and selects petroleum geology,sedimentary petrology,reservoir geology as a theoretical guide;combined with core,logging and other basic geological data and mercury injection data,cast thin section,scanning electron microscopy and other analysis assay,then analyzed distribution of sand body,sedimentary microfacies and the microscopic pore-throat structure of Chang 8-1 reservoir in the study area.Finally,the following results are obtained:In the sedimentary microfacies,the reservoir sand-bodies of Chang 8-1 are mainly distributary channel sediment,mouth bar sediment,channel margin sediment;the non-reservoir sand-bodies are mainly interdistributary bay sediment.In the microscopic pore-throat structure,the pore types of the Chang 8-1 reservoir are mainly intergranular pores,feldspar pores,and their combination;the throat type is mainly sheets or bent sheet throat,necking throat,and tube-shaped throat;the combination of pore and throat is mainly large-med pore and micro-throat type.The pore and throat of the study area was fine,and the porosity was positively correlated with the permeability;the larger throat has a great contribution to the seepage of oil and water in low or ultra-low permeability reservoir.The factors that affect the micropore throat structure are mainly sedimentary facies and diagenetic facies. |
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