Abstract: Formation micro-resistivity scanning imaging logging (FMI) can provide visualized and high-resolution images, which has obvious advantages in describing heterogeneous strata containing complicated reservoir spaces. Combined with the core and conventional logging data, FMI images are used to detailedly describe the key intervals of the Ordovician carbonate reservoir in 8 prospecting wells of Tahe oilfield, and a geological interpretation model is established for FMI logging. The model is used in the non-coring intervals and the lithologies of the Ordovician reservoir are identified, which is dominated by calcarenite, sand-clastic micrite, micrite and calcite dolomite; the reservoir spaces are composed by pores, caves and fractures. The sequence unconformity surfaces can be identified by using resistivity difference, reservoir space distribution and lithological and structural markers displayed in FMI images. Based on the single-well facies analysis and well tie correlation, it is considered that the sequence unconformity surface resulted from tectonic movement, karstfication and regressive erosional dissolution controls the development of the reservoir spaces