Texaco patented and developed the Quantitative Fluorescence Technique (QFT) introduced in the early 1990s as a well-site method to determine the fluorescence of crude oil extracted from the sample. QFT was a substantial improvement over the visual technique for detection of oil in drill cuttings or cores but still provided only a relative measure of oil in the sample.
Further development resulted in an improved method called QFT2™ . QFT2™ involves a two-point fluorescence measurement that yields estimates of both absolute oil quantity (weight % oil) and oil type (API gravity). The speed, accuracy and ease of application make QFT2™ a practical tool for the determination of oil concentration and API gravity at the well-site.