Standard gamma ray tools can be misled by uranium-rich "hot shales" or radioactive non-shale minerals like feldspar. The NGI’s ability to isolate uranium (CGR) allows for a more precise calculation of shale volume ( Vshcap V sub s h end-sub
Modern versions of the tool can process the density inversion downhole, transmitting only a calibrated density curve and error bar to the surface. This reduces telemetry demands and improves real-time decision-making for intervention crews. schlumberger ngi tool