Taking the practice of electric logging in Jinta Basin as an example, the characteristics of resistivity of salt water and fresh water in the aquifers with different lithologic property are summarized, the relation between inflow of water and thickness of aquifer, the relation between salinity and resistivity of aquifer are expounded.

In waterflood-production oilfields, formation water resistivity of water-flooded zone is not only the basic parameter for water-flooded zone evaluation but also the "bottle neck" which restrict water-flooded zone evaluation.

Based on large number of core experiment data, a method for quantitatively deriving formation water salinity (formation water resistivity) and capacity of cation exchange of the theoretical model of spontaneous potential and induced polarization potential is established.

Study on logging response mechanism shows that,reservoir with high mud and irreducible water saturation,thin layer and interlayer are main causes for forming low-resistivity oil layer,while being tight and containing calcareous and residue oil are main factors of forming high-resistivity water layer.

Modeling for computing resistivity of formation water;

Secondly, the relation between resistivity of formation water, spontaneous potential(SP), mud resistivity, and shale content is characterized by water analysis and SP data.

Rw,the resistivity of formation water used in the Archie formula,should be strictly applied.

Analysis and application of characteristic parameters of normal probability frequency distribution map of apparent formation water resistivity