In contingency situations when logging in open hole is not possible or too risky, cased hole logs are often considered as an alternative to evaluate the reservoirs in the San Jorge Gulf basin (CGSJ). Cased logs together with mud logs allow appraising the multi-layered reservoirs in the Bajo Barreal and Castillo units.The formation water low salinity makes difficult discriminating oil from water just using resistivity. The situation does not change if cased hole logs are used to emulate resistivity from the thermal cross capture section (Sigma), known in the basin as Pseudo logs, which can be utilized for inter-well correlations, but often are inconclusive for assessing hydrocarbon potential. In this contribution we propose an alternative evaluation methodology using advanced Pulsed Neutron logs (PNL) featuring high resolution gamma ray spectroscopy, which measure the Carbon concentration in the formation for a reliable estimation of the Total Organic Carbon (TOC), directly associated to the hydrocarbon.The development of modern PNL tools equipped with high resolution detectors allows measuring the elemental concentrations from the capture and inelastic gamma ray spectroscopy, and from this information evaluate lithology and TOC at acceptable logging speeds considering the zone of interest long intervals, typically between 1000 and 1500 meters long. The proposed methodology was tested with two new-generation PNL tools. The first device was originally intended for openhole logging and is equipped with a single large detector for high-quality spectroscopy analysis. The second device is a multiple-detector slim PNL tool, which besides the TOC and other spectroscopy outputs also provides sigma, neutron porosity and measures a new property, the fast neutron cross section (FNXS), useful to detect and quantify gas. The case studies presented correspond to examples in new wells logged as contingency and old wells logged during workovers. The candidate intervals were previously identified using correlations from the static geological model and complemented with the mud logging information. In all cases we achieved good correlation between the zones with TOC, the static model, and well test results.This experience illustrates the adaptation and application of new technologies to the development of mature fields where conventional openhole resistivity-based analysis is ambiguous. Future tasks include adjusting the technique for quantitative analysis and its use in deeper, more challenging unconventional reservoirs in the basin.