A preliminary assessment of the relationship between the mineralogy and diagenetic history of four argillaceous rocks and their thermomechanical properties

A primary purpose of this study was to develop reproducible, quantitative methods to determine the bulk mineral composition and diagenetic history of argillaceous rocks and to attempt, in a preliminary way, to explain the thermomechanical behavior of several formations that were being measured by others. This report presents the results of several methods of analysis [specific-gravity determinations, water contents, chemical analyses by x-ray fluorescence (XRF) analysis, quantitative mineralogical analyses by x-ray diffraction (QXRD), preferred orientation analyses by x-ray diffraction, and scanning electron microscopy (SEM) of fractured samples] that were used to study selected samples from the Conasauga Group, the Rhinestreet Shale, the Pierre Shale, and the Green River Formation to determine their mineralogical character and the effects of diagenesis on these materials. The results were then related to thermochemical test data that were obtained on samples from the same cores. Specific-gravity determinations on ''as-received'' samples ranged from 2.00 for the Green River Formation to 2.75 for the Rhinestreet Shale. Exposure to the atmosphere resulted in a small net gain (+0.5) in specific gravity for the Conasauga Group samples and a net loss (-0.11) for the Pierre Shale samples. Water contents, determined by heating to 105/degree/C for 1 h, averaged 0.8% by weight for the Conasauga Shale, Rhinestreet Shale, and Green River Formation samples. The water content determined for the Pierre Shale samples was 12.1 wt %