The difference of physical parameters in oil-gas-water are premise that geophysical well log can be used for fluid typing. However

the identification of oil-gas-water layers is also dependent on lithology and pore structure of reservoir rocks. Porosity index M is an important parameter when electrical resistivity is used for the fluid typing of reservoir rocks with complex pore structure. The M value may be estimated by the micro-resistivity imaging logs

combined with conventional porosity logs. Low-resistivity reservoirs are caused by different reasons

therefore the different methods are needed for their fluid typing. The improved data collection pattern is suitable for a thin-interbedded reservoir; the improved interpretation model is suitable for the low-resistivity reservoirs caused by pore structure and mud content. In recent years

some progresses have been made in fluid typing using NMR logs. On the basis of original differential spectra

many new methods

such as time-domain analysis method

mobile spectra method

diffusion-forcing method and diffusion-editing method

have been successively developed and improved.