Saturation Determination and Fluid Identification in Carbonate Rocks Based on Well Logging Data: A Middle Eastern Case Study

In the Middle East, there remain many technical challenges in water saturation evaluation of carbonate rocks and effective identification reservoir fluid properties. The traditional Archie equation is not applicable to reservoirs with complex pore structures varying space distribution, as are obvious “non-Archie” phenomena. this paper, by analyzing experimental data on rock resistivity target formation study area relationship between stratigraphic factors porosity, previous fitting method was modified a result using actual while avoiding cementation index way improve Archie’s formula evaluate saturation. Based improved formula, mathematical differential operation porosity carried out resistivity. calculation results irreducible were used calibrate oil layer, layer calibrated when 100%, allowing for novel property method. This total can effectively identify oil-down-to (ODT) water-up-to (WUT) levels an oil–water system then accurately divide transition zone layer. When applied, good agreement production conclusions test accuracy rate 89.95%. Although use geophysical logging from open-hole wells combined only similar time time, it possible compare different periods construct profiles observe changes ODT over guide development adjust plans. proposed meet requirements block low cost easy implementation, which provides new rapid