Analysis Of Jurassic Residual Oil Reservoir Genesis And Log Characteristics In Ordos Basin

This thesis is about the study of reservoir of Jurassic Formation Longdong and Jiyuan region in Ordos Basin.As a result of large number of low contrast oil reservoirs in the Jurassic Yanan formation,Oil accumulation mechanism and distribution is unclear,the well log interpretation is relatively low,there still comes the problem about identification of oil and water layers and most of the reservoir interpretation is on the high side.This paper first proposed the oxidized residual oil is the main reason causing difficulties in oil and water layer identification.Because of the reservoir containing oxidized residual oil appears neutron log and density log anomaly characteristics,and part of the layer aquifer resistivity increases.In order to solve the problem,to improve the accuracy of log interpretation in the study area,correctly understand the characteristics of the Jurassic reservoir,this study is focus on the identification and evaluation method,genetic analysis about residual oil reservoir based on well log characteristics.Through the analysis of 166 wells log characteristics,combined with the geochemical research,core analysis data,oil testing conclusion,palaeogeomorphology and reservoir background.These residual oils are related to the structural adjustment and evolution of paleo oil reservoir,reservoir erosion and oxidation,and crude oil migration and alteration.The paleo oil reservoir can be verified by the organic inclusion recognition technique and the particle fluorescence titration technique.And the use of well log data describe residual oil of Jurassic vertical and plane distribution,with Chang 7 source rock thickness distribution of contrast,can basically determine the migration of ancient oil path,recognize the hydrocarbon filling history.