Formation Characterization in a Different Perspective: Drill Cuttings Analysis Revisited

For years, drill cuttings have been the first contact with real subsurface formation material in drilling operations. They also have been restricted to an information element used by mud loggers and some specific geologic purposes such as microfossil studies. Once used for these purposes, they usually disappear from the scenario of exploration and production upstream activities. Conventional procedures on sample preparation and advanced visualization analysis techniques (Scanning Electron Microscopy, X-ray Dispersive Energy Spectroscopy, Backscattered Electron Imaging and Digital Image Processing and Analysis) enable drill cuttings to supply important information for different end users, including petrophysicists, reservoir engineers and drilling engineers. This paper presents some examples of the analysis of field samples, showing the wide range of data possible to obtain: modal mineralogy and chemical analysis, lithological classification and provenance, log correlation, textural analysis and pore geometry determination, inorganic mud additives, and metal debris evaluation from wear of BHA. Though less precise in terms of depth origin, the sample supplies a significant amount of information making this approach a valid option when economic restrains cannot consider coring operations but formation characteristics are needed for field development and working fluids design.