Shale from Rock Springs

Figure 9. Chromatogram of shale oil from Rock Springs No. 9, a true in situ experiment. The alkene/alkane ratios are very low (coking) and the naphthalene content are very high (combustion and associated cracking). The naphthalene/methylnaphthalene ratios are high compared with the...

The crude shale oil used in this study was obtained from an in situ combustion retorting experiment at Rock Springs, Wyo. (I, 2), during the last week of the experiment and is considered a representative steady state oil. Properties of the in situ crude shale oil are shown in Table I. 

Procedure. Green River site 1 was located 5 mi west of the Rock Springs sites 4 and 5. The oil shale zone of interest, at approximately 346-385 ft, was selected after studying the analysis of cores cut from an earlier well. As determined by Fischer assay, oil yield of the cored section averaged about 21.0 gal/ton. 

Figure 4 Sulfur isotope summary for black shales from the Pierre Shale of the Cretaceous Western Interior, North America (Gautier, 1986, 1987), and the Jurassic Posidonienschiefer and Jet Rock (Raiswell et al., 1993). For comparison, the maximum fractionation observed in the Posidonienschiefer by Fisher and Hudson (1987) is also shown. The isotopically uniform and strongly S-depleted pyrites of the Jurassic shales and the Cretaceous Sharon Springs Member of the Pierre Shale—like the sediments of the modern Black Sea and Cariaco Basin (Figure 7)—are diagnostic of euxinic (water-column) pyrite formation (see Section 7.06.3.4.2). By contrast, the Cretaceous Gammon Shale shows the S enrichments and broad range of 6 S values possible under oxic depositional conditions (Gautier, 1986, 1987).

The through-flow zone has so far been described in a simplified mode, assuming all the hosting rocks are homogeneously permeable. Deviations from the simplified L-shape of the flow path are caused by the presence of hydraulic barriers, such as clay and shale, that may in certain places block the downflow and create local perched water systems and springs (Fig. 2.16) or cause steps in the path of the lateral flow zone. But the overall L-shape is generally preserved, as the water of perched systems finds pathways to resume the vertical downflow direction. 

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