Methods Of The Fluid Identification Of Putaohua Oil Reservoir In Cha48Block

Putaohua formation in Cha48block has occupied an important position in thedevelopment of Jilin Qianan oilfield. As there are problems about uncertain undergroundfluids features and imprecise identification of underground fluids,they affect the increasing ofoil reserve and production in this area. Therefore, it is necessary to focus on front line subjectsand hot issues, concentrate on oil and water relationship in study area, and solve the mostdifficult problem, in order to accomplish stable oil production. In the meantime, we canimprove fluid identification technique through research, and increase integrated well logevaluation technique, and prepare for long term development of oil field.This paper is based on core data, testing and well log data of key wells in Cha48block,and through studying reservoir properties and relationship between four attributes of reservoir,established plates of four reservoir attributes. By analyzing well log response properties inPutaohua formation of Cha48block, we can summarize the cause of low resistivity oilformation and high resistivity water formation in this study area. Due to various types of welllogging and the span of well logging, we first use trend surface to correct well logs, improvewell log quality; then we pick gamma, sonic, induction, lateral resistivity logs’ eigenvalues,using regression analysis to build a reservoir interpretation model; Using a variety of methodsto determine lower limit of effective thickness, we can provide a standard for reliable well logprecise interpretation; and then practise this model in Putaohua formation of Cha48block todo a secondary well log interpretation. Use two parameters intersection method anddiscriminate analysis to identify oil-water layer. Through study of typical reservoir sectionbetween wells in study area, we can determine reservoir type and oil-water distribution in thisarea. And by combining sedimentary facies and structure features, we can summarizedistribution of oil and water and its controlling factors.After the research in this area, we believe that main causes of low resistivity oil reservoirare small grain size, poor reservoir quality, clay and high electrical conductivity, developmentof micro-pore structure, trap and pore structure is not quite good. High resistivity water layeris caused by residual oil and content of Calcium. After study typical reservoir section inPutaohua formation, we believe that reservoir types are mainly lithological reservoirs andfault lithological reservoirs, and furthermore, the distribution of water-oil is controlled bystructural and lithology.