The Study On Chang 9 Reservoir Logging Evaluation Of Y176 Wellblock In Jiyuan Oil District

Chang 9 reservoir of Y176 well area,JiYuan area is typical extra-low permeability oil layer.At present,owing to the complicated oil-water relationship of Chang 9 oil layer,the accuracy of logging evaluation is low.The description of the fine reservoir characteristics is restricted.Therefore,it is necessary and urgency to carry out low porosity and low permeability reservoir logging evaluation in this area.This thesis takes Triassic Chang 9 reservoir of Y176 well area,JiYuan area as the main object of study.Based on geological data,core data,logging data and dynamic production data of Y176 well area,the research of fine stratigraphic classification and correlation,sand body distribution and sand top micro structure characteristics,sedimentary micro facies characteristics,reservoir characteristics,“four-property relationship” and the logging interpretation model of reservoir parameters,second logging data interpretation,distribution characteristics of reservoir parameters and reservoir heterogeneity is carried out.Finally,static database of reservoir geological parameters of Y176 well area is established.It lays a good geological foundation for the comprehensive evaluation of reservoir.The research shows that Chang 9 reservoir of Y176 well area can be divided into Chang 91 and Chang 92(not drill,not study).Chang 91 reservoir can be further divided into Chang 911 and Chang 912.Sediments of delta front occurred in the study area.Sedimentary microfacies are mainly underwater distributary channel,underwater natural levee and underwater distributary bay.The river channel presents from north-east to south-west.And the river channel grows wider to the north-east.The overall structure is simple,and presents the northeast high and the southwest low.Besides,the successive small nose-like uplift develops.The sand body distributes in band from north-east to south-west,better extensibility and connectivity in plane.The thickness of north-east area sand body is large and thickness of others is much thinner.Among them,the thickness of Chang 911 is the largest,high oil potential.It is the main oil layer of the study area.The porosity,permeability and oil saturation of Chang 911 and Chang 912 presents similar distribution in plane.On the whole,the north-east area is better and the south-west area is worse.And there is certain succession between the two small layers.The diagenesis of this area is mainly compaction,cementation,metasomatism and dissolution.The Chang 911 reservoir presents strong heterogeneity,and the Chang 912 reservoir presents intermediate heterogeneity.The relationship of lithology,physical property and oil content is analyzed and revealed by electrical characteristics.The result shows that there is a linear relationship between the reservoir physical properties and the sand body thickness,sedimentary microfacies and reservoir heterogeneity.In this paper,the research in this area as reservoir development technology policy makers have some guiding significance.