Well logging geology is guided by the theories of geology and well logging which comprehensively uses various well log data to solve problems existing in basic geology and petroleum geology.Well logging geology has been widely used in the various aspects of oil and gas exploration and development in the past decades.With the rise of unconventional hydrocarbons,well logging geology is facing multiple challenges and new explorations,and it is urgent to establish a comprehensive method and theoretical system of well logging for unconventional hydrocarbons.This paper takes the publication of “Well Logging Geology: Second Edition” as an opportunity,and systematically generalizes the origin,development,the main research contents and research method flows.Then it summaries the matching relationships of well log data with seismic data and geological information,and the features of the vertical resolution interval of logging methods with different detecting characteristics are analyzed.Then,the applications of well logging geology in the analysis of borehole structure,sedimentary characteristics research,sequence stratigraphic division,in situ stress direction determination and calculation of in situ stress magnitude,identification and evaluation of wellbore fracture, evaluation of source rocks and “seven properties relationships”of unconventional oil and gas resources.However,due to the limited load capacity,the inconsistency of logging and geological information,and the ambiguity of logging data itself,there are still some problems existing in well logging geology conversion and the fusion of unconventional hydrocarbons logging evaluation and artificial intelligence.Therefore,strengthening the basic petrophysical research and mining the geological information in the logging curves integrated with artificial intelligence will definitely expand the accuracy and width of well logging geology,therefore it can be better applied to the unconventional hydrocarbons evaluation.