Shale varies much and interpretation for shale is difEcult.

Analysed are different functions of the clays and shales in reservoir conductivity and their effects on log interpretations.

Research on rock mechanic characteristics of slight weather argillaceous sandstones in Sichuan Basin;

But the clean sand model through which we can calculate for- mation water resisitivity is unsuitable for argillaceous sandstone.

The argillaceous sandstone reservoir has a large distributed area in Linnan oilfield.

A comparative electric petrophysical experimental study by oil displacement method on artificial pure sandstone samples and natural samples with low resistivity concluded that no matter what kind of sample is,one of important factors causing low resistivity pay is the high irreducible water saturation which is determined by the shale content and the complication of pore structure in the rock.

Then necessity and feasibility of determining clay content and shale content are studied with different logging response curves.

At present based on GR inversion of lithologic recognition,shale content inversion is used to predict the channel sandstones with satified result.

Some viewpoints including the maintainence of the metabolic capability of functional bacteria in pit mud was the important base for pit mud quality and could ensure high-quality liquor-making etc.