Genisis And Logging Interpretation Of Low Resistivity Reserviors Of Paleogene In Subei Basin

With the deep of oil exploration and development, low resistivity reservoirs’ genesis and their interpretations become more and more important in oil baring formation. In this paper low resistivity reservoirs genesis were analyzed, and also the well logging and interpretation methods were studied in different blocks whit different characters.Based on drilling cores, well logging data, analysis data and understanding of experts at home and abroad, the genesis of low resistivity reservoirs were concluded, which were caused by grain size, clay contents, additional conductivity of clay rocks, high irreducible water saturation, and high formation water salinity. By analyzing hydrocarbon reservoirs and geological characters, the influencing factors of low resistivity reservoirs’ genesis in research area and different reasons of them were studied. Fine particle sizes of rocks were main causes and universal characteristic of low resistivity reservoirs in Subei basin. High clay ratio and high additional conductivity caused low resistivity in Sha-nian, Wa-zhuang oilfield. In Huang-jue and Ma-jia-zui districts, lithological reservoirs and hydrophilic wettability may main causes of low resistivity of reservoirs. Thin interbeds of sandstone and mudstone, and high bound water saturation created the causation of low resistivity in East Biang-tan oilfield.Based on the systematic analysis of the relationship between the oil baring formation of lithology, electric property, porosity, permeability, and hydrocarbon-bearing property, the standards of well-logging, measurements of physical quantities or calculation between the geological physical quantity of high precision, strong applicability of oil, water, dry layers interpretation standards in well-logging in different area and different layers were built up, and those results were applied in mining new reserves and the potential reserves in old oilfields. Using refined logging interpretation charts, formations of E1f3 in 85 old wells in East Bian-tang area, Yang-jia-ba area, Sha-nian area were reviewed, and 193 oil baring layers of 382.2m were interpreted.