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.

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

Cased-well Formation Resistivity logging is one of the new well- logging methods which was proposed during the later 90\'s, because of its capability of measuring the formation resistivity in cased borehole, which is very different from the traditional open-hole well logging, it can be used in different stage in oil and gas development.