Application of improved PICKETT method to identification of low-resistivity pays in Y Oilfield

The analyses of core data (such as porosity,permeability,capillary pressure curve,electrical parameters,relative permeability,thin section,clay mineral),logging,well logs and well testing for low-resistivity pays in Y Oilfield show that the low-resistivity pays are mainly caused by some factors including ① complicated porous structure, especially high irreducible water saturation in micro-porosity system;② high volume clay minerals (kaolinite and illite) adsorbing abundance of irreducible water; ③ high cation exchange capacity;④ deeper invasion of saline mud filtrate. PICKETT method is mainly based on cross-plot of deep laterolog and porosity from well logs and core data. The height of free water level of pay was introduced into the initial PICKETT method to improve the PICKETT method. The improved method has been successively applied to identify the low-resistivity pay in Y Oilfield.