关键词: 测井相, 主成分分析, 最优化, 双孔隙水, 矿化度, 岩电测量

Abstract: The factors leading to low contrast resistivity have been classified into inner and outer causese by analysis of some oil fields' information.The inner causes are the variations of lithology,porosity and permeability,and the outer cause is the variation of non-formation factors,such as the changing of formationm water salinity.The concept of log facies is first used for identifying low contrast resistivity reservoir,and shows satisfactory results.A Dual Porosity Water Model has been put forward and perfected by using core electric measurements with multi-salinity waters for the determination of model parameters,which are obtained by linear regression and theoretical computation.The result of an example shows that the water saturation of low contrast resistivity oil/gas formation is very close to its irreduciable water saturation,and the errors are usually no more than 5%.Furthermore,these methods aimed at common uses have been confirmed effective in a number of oil fields.

Key words: log face, partial component analysis, optimization, dual porosity water model salinity, core electric measurement