Most of Niger's oil exploration and production activities take place in the Termit Basin. The Paleogene Sokor1 Formation, an important exploration target in the Termit Basin, is a typical sandstone hydrocarbon reservoir. The research presented in this paper used core, water samples and wireline logs, collected in the Dibeilla prospect to determine factors impacting the occurrence of low resistivity oil/gas reservoirs during their diagenetic processes to avoid exploration extra-cost and to recover the total reserves. Cores were analyzed based on thin sections, scanning electron microscopy, X-ray diffraction, and capillary pressure test. Wireline logs were analyzed using the Combined Log Pattern technique. The distributions of all potential influencing factors on porosity and permeability were quantified, making it possible to assess the influence of all potential controls on resistivity logs reading regarding to the fluid type. Diagenetic processes in the Sokor1 oil/gas reservoirs with low resistivity include cementation and dissolution, apart from mechanical compaction. Authigenic clay minerals, pyrite and siderite that account for resistivity controlling factors, occur as pore-filling and pore-lining cements, increase the reservoir conductivity. Sedimentary facies with fine lithological features resulted from relatively weak hydrodynamic deposition conditions induced by irreducible water and dual pore-structure system are the primary causes related to resistivity reduction in oil/gas saturated reservoirs. The low resistivity oil/gas reservoirs identified are the result of mix factors. Results demonstrate the robust application of combining diagenesis and Combined Log Pattern in predicting favorable reservoirs, useful in reducing exploration risk in undrilled areas and oilfields with similar geologic settings.