The inaccurate delineation of the sand intervals in well logs can significantly affect the porosity, permeability, pore-size geometry and net-to-gross ratio of the reservoir units. This study utilized well log cross-plots to accurately delineate the lithologic units and also used petrophysical evaluation methods to determine the reservoir properties of the sandstone intervals in three wells (L, M, N wells) of the Daura field, Niger Delta. The cross-plots of the gamma ray with density, gamma ray with sonic and gamma ray with depth were generated using the Hampson Russel software. The result of the cross-plot clusters shows two major lithologies of sandstone and shale with occasional intercalation of sand and shale units. Fluid detection analysis shows that reservoirs L3 (well L), M4-M5 (well M), and N2-N3 (well N) were found to contain oil, while reservoir M2 (well M) contains gas. The rest of the reservoir intervals in the three wells contain water, and the average porosity ranges from 14.23 to 28.01%. This study has shown that the cross-plots approach can be used to accurately delineate reservoirs for further formation evaluation. It therefore means that an outright estimation of petrophysical properties on wrongly delineated reservoirs can significantly affect the porosity, permeability, pore-size geometry and net-to-gross ratio of the reservoir units.