Sediment Provenance Study of the Marcellus Shale: An Analysis Between the Organic-Rich Facies and Their Depositional Histories
Currently, no geological model exists to explain the variability and distribution of organic-rich facies in the Marcellus Shale. Within the central Appalachian basin, there are two “sweet spots”, one in Northeast Pennsylvania and another in Southwest Pennsylvania/North- Central West Virginia. In these areas, the Marcellus Shale contains thick accumulations of organic matter and are highly productive for natural gas. In contrast, many studies and production reports have shown that in other areas, the Marcellus Shale is relatively organic- poor. One possible explanation for the lower organic content is that detrital dilution was greater in these areas compared to surrounding productive regions. This hypothesis will be tested by analyzing the provenance of inorganic detritus in the Marcellus Shale. Recent study of the MSEEL (Marcellus Shale Energy and Environmental Laboratory) well in north-central West Virginia revealed input from the Superior Craton decreased and input from the Acadian mountains increased as TOC in the Marcellus decreased up-section. This suggests detrital dilution of organic matter should exert a decreasing influence southward along the basin axis. To examine this idea further, a comparison will be made between the MSEEL well and two wells located in other areas of the basin. Facies classifications and provenance interpretations will be made in the Marcellus Shale intervals based XRD mineralogy and XRF/ICP-MS major/trace element geochemistry. These data will be combined with Sm-Nd analysis analysis to further constrain provenance. Raman spectral analysis will be used to evaluate thermal maturity and its relationship to organic richness of Marcellus facies. Ultimately, these data will be used to model the depositional environments, sediment provenance, and thermal maturity to explain the variation in organic matter content in the central Appalachian basin.
AAPG Datapages/Search and Discovery Article #90335 © 2018 AAPG 47th Annual AAPG-SPE Eastern Section Joint Meeting, Pittsburgh, Pennsylvania, October 7-11, 2018